HgMnTe > HgZnTe. As table 1 shows the measured photoconductor lifetimes are comparable to those obtained on high-quality samples converted by the conventional anneal in mercury vapour."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002271_robot.1988.12256-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002271_robot.1988.12256-Figure3-1.png",
+ "caption": "Fig. 3 Finger Structure of UCSB HAND: Five Bar Closed Link Mechanism",
+ "texts": [
+ "2 shows the UCSB HAND developed in the Center for Robotic Systems in Microelectronics, University of California Santa Barbara. The robot hand has three 3 DOF fingers driven by nine DC servo motors. This hand was developed to research coordinative manipulation by multiple robotic mechanisms [8]. Since precise force control of each finger is required, simple gear reduction and transmission system were adopted. The reduction ratio of each motor is only sixteen. By using the five bar closed link mechanism and a special transmission, the finger structure was simplified as shown in Fig.3, and all the motors were located in the wrist portion. The transmission is shown in Fig.4. The dynamics of the closed link finger mechanism was computed using the computational scheme proposed in section 2. The coordinate frames and the corresponding open link tree structural mechanism are shown in FigS. The coordinate frames were defined according to the Denavit-Hartenberg notation [9]. O i indicates the rotational angle along the z axis of the (i-1)-th coordinate frame. e,, e,, and O3 axes are the actuated joints"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000704_a:1008228120608-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000704_a:1008228120608-Figure2-1.png",
+ "caption": "Figure 2. The failure locus in the plane X1\u2013X2. Global stick phases are represented as straight lines parallel to the bisection line of the first quadrant. A slip phase starts when a trajectory reaches the failure locus.",
+ "texts": [
+ " The dynamics of the mechanical system of Figure 1 are described through the time histories of positions and velocities of the blocks which have been defined in a non-dimensionalised form [7]: X1 and X2 are the displacements of the first and the second block, respectively, relative to the configuration where the three springs are simultaneously unstretched, V1 and V2 are the velocities of the first and the second block. The limit conditions that indicate the passage from the stick-motion to the slip-motion and vice versa are given by the equations: X1 + (X1 X2) = 1; (3a) X2 + (X2 X1) = : (3b) Equations (3) define the failure locus in the plane of the variables (X1;X2) (Figure 2). When the blocks are pulled by the belt their velocity is constantly equal to that of the belt; when the blocks slip their motion is described by the equations: X1 +X1 + (X1 X2) = 1=(1 + jV1 Vdrj); (4a) X2 +X2 + (X2 X1) = =(1 + jV2 Vdrj): (4b) In Equations (3) and (4) is the ratio between the stiffness of the coupling spring and the stiffness of the two other springs, is the ratio between the maximum static friction force acting on the second block and the same force acting on the first block, is the shape coefficient of the dynamic friction law, Vdr is the (non-dimensionalised) velocity of the belt, which is constant",
+ " The dynamics of the stick-slip system generate a one-dimensional map of the variable d [4], the so-called event map, that is the main object of this paper and will be indicated by f ; Figures 4 and 5 show two important features of the one-dimensional map: its graphical representation is in general much simpler than that of the global motion and it is a single valued function. The second property of the map was found in all the numerical examples that were taken into consideration. If the driving velocity is small the points lying on the line AC into the failure locus represent all the transient motions once the possible global slip phases have ceased [7]. The stretch length d may vary between 0:6764 and 0.6764 which correspond to the points C and A, respectively, of the failure locus of Figure 2. Choosing a grid of initial conditions on this line, it is possible to investigate the global dynamics of the system. Figure 6 is an illustration of the global dynamic behaviour of the system by means of the one-dimensional map. In Figure 6 the thin lines indicate the transient behaviour whereas the thick lines are composed by points belonging to the steady state behaviour of the system. There exist (at least) two attractors, indicated by the numbers \u20181\u2019 and \u20182\u2019, so that the interval CA, where the map is defined, is divided in two basins of attraction; the two sub-intervals B1 and B2 constitute the basin of the attractor \u20182\u2019, the other sub-intervals are the basin of attraction of the attractor \u20181\u2019"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002148_rob.4620110104-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002148_rob.4620110104-Figure3-1.png",
+ "caption": "Figure 3. Deformation by comparing B and %.",
+ "texts": [
+ " This is done by defining a deformation vector field A from the intrusion vector field. We can write * where h is the homeomorphism from S\"-' to R and 0 is the deformation vector field transforming B into 8. The function a is a normalizing function ensuring that E is still an imbedding of Sn-'. Figure 2 summarizes these different concepts for the 2-D world. The interaction component 8 can be chosen as a deadband value for the information boundary 8. In this case, E is deformed if and only if the information boundary manifold B is \"smaller\" than E (Fig. 3). Thus, the normalizing function a works as a trigger. From relations (2) and (3), the formal expression of Q can be written: = 0 otherwise (4) We have to note that possible discontinuities of the information boundary are finite and thus can be easily deleted. For instance, such is the case of the central observation of a polygonal room (Fig. 4). 2.4. Control loop The first cause of the interaction component deformation is the information intrusion due to the prox- imity of moving obstacles. The second cause is the internal control El, = p ( r ) of the robot for compensating this intrusion"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003231_491596-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003231_491596-Figure7-1.png",
+ "caption": "Fig. 7.\u2014Diagram of the twisted disk model showing the relevant parameters. The disk is viewed at elevation obs \u00bc 0 . Inset: The same disk viewed at obs \u00bc 90 , showing the disk twist angle tw.",
+ "texts": [
+ " We seek to test this possibility by comparing the observed hard- and soft-pulse profiles to a relatively simple model, in which a warped, twisted inner accretion disk is illuminated by a rotating X-ray pulsar beam. 5.1. Illuminated Disk Model Our model does not describe the entire disk but only the region close to the magnetosphere where the bright reprocessed component must be emitted. The disk model consists of a series of concentric circles with varying tilt and twist relative to each other with distance from the center (see Fig. 7). A similar shape has been inferred for the large-scale structure of the disk in Her X-1 from changes in the pulse profiles with superorbital phase (Scott et al. 2000; Leahy 2002). Warped and twisted structures have also resulted from numerical simulations of warped disks (Wijers & Pringle 1999) and of gas-magnetosphere interaction (Romanova et al. 2003). In our calculations we place this surface (we refer to it simply as the \u2018\u2018disk\u2019\u2019) at roughly the location of the magnetosphere ( 108 cm) and test if precession of such a surface around the disk axis can create changing soft-component profiles similar to those observed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002927_fuzzy.1992.258722-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002927_fuzzy.1992.258722-Figure4-1.png",
+ "caption": "Figure 4: Nonlinearity of the output function of FCMAC suppresses noise. Three fuzzy weights Wi(i = 1 ,2 ,3 ) are used to generate the response fuzzy set. Suppose pw;(y + e ) = pw,(y) for some e > 0. Because of the nonlinearity of the defuzzification, the new fuzzy centroid will be less than B + e .",
+ "texts": [
+ " Note especially that f ( x ) of CMAC is a linear function of weights; however, f(x) of FCMAC is a nonlinear function of fuzzy weights. Linear functions make computation and analysis comparatively easy. But linear functions do not suppress noise, and thus they are not robust. Noise due to mapping collisions, producing an undesirable generalization between distant inputs, will be suppressed by the defuzzification process. Nonlinearity of f ( x ) increases FCMAC's computational richness and makes it robust in the case of mapping collisions (see Figure 4). The cost of nonlinearity is the extra computational burden in defuzzification process. In particular, computing the fuzzy centroid in the centroid defuzzification scheme requires division. Since FCMAC extends CMAC by including fuzziness in the system architecture and the mathematical data, the following question is naturally raised: Can a FCMAC module be reduced to a CMAC module? The answer is yes, as presented by the following theorem. Theorem: For a FCMAC module, if all sensors of S are crisp and all weights are nonfuzzy singletons3, then the FCMAC module functions as a CMAC module"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002310_1.2831616-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002310_1.2831616-Figure1-1.png",
+ "caption": "Fig. 1 Apparatus",
+ "texts": [
+ " The purpose of this study is to design and make an apparatus that can measure the surface separation and normal force accu rately and to measure fluid lubrication film thicknesses less than 10 nm using the new apparatus. Results of experiments are compared with the conventional lubrication theory considering the van der Waals force and the meniscus force. Contributed by tlie Triboiogy Division for publication in the JOURNAL OF TRIBOLOQY. Manuscript received by the Triboiogy Division May 4, 1995; revised manuscript received October 17, 1995. Associate Technical Editor: C. Cusano, Apparatus and Specimens A new apparatus that the authors developed is shown sche matically in Fig. 1. Lubricated surfaces are in a crossed cylinder configuration, which is geometrically equivalent to the configu ration between a sphere and a plane (Israelachvili, 1992). Opti cally polished glass lenses are used as the two cylindrical sur faces, and one of the lenses is supported by a rigid arm, the other by a flexible double cantilever spring. When certain forces act between these surfaces, the cylindrical surface supported by the cantilever spring is displaced, then the normal displacement is measured by a high resolution non-contact capacitive dis placement sensor",
+ "35 mPa-s\" d:(Hom and Israelachvih, 1981), e:(Israelachvili, 1992), ** denotes the measured value. Experimental Procedure Square sheets of mica with a size of 10 X 10 mm are cleaved to a thickness of 10~30 jim and then glued on the cylindrical optical lenses with cyanoacrylate paste. Curvature radius, R, of the cylindrical surface is measured by a surface roughness tester (R = 10.15 \u00b1 0.15 mm). Mass of the cylindrical lens and plates, which are attached to the end of the double cantilever spring (see Fig. 1), is measured by a electric balance. The two cylindri cal surfaces are then set to the apparatus. The free vibration frequency of the resulting spring-mass system is measured by FFT analyzer, and the spring constant, fcj, of the double cantile ver spring is calculated from the measured natural frequency of the spring and the mass by a one-degree-of-freedom lumpedmass/spring model (ks = 132.5 \u00b1 2.5 N/m). Parallel sliding of the elastic stage 1 is ensured to less than 7 nm (perpendicular to the sliding direction)/100 fxm (sliding distance)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003927_1.1828069-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003927_1.1828069-Figure3-1.png",
+ "caption": "Fig. 3 Schematic diagram of the friction measurement rig",
+ "texts": [
+ " The Rq parameter for this artificial roughness was 71 nm. For the isotropic rough surface tests, a rough AISI 52100 steel ball, manufactured by early withdrawal from the ball-finishing process, was used, with roughness parameter Rq579 nm. A 3D plot of the surface of the rough steel ball obtained with an interference microscope is shown in Fig. 2. 2.2 Friction Measurement. Friction measurements were carried out using a minitraction machine ~MTM!. A schematic diagram of the testing rig is shown in Fig. 3. A lubricated contact is formed between a steel ball and a steel disk, which are driven independently by electric motors at any desired combination of 224 \u00d5 Vol. 127, JANUARY 2005 rom: http://tribology.asmedigitalcollection.asme.org/pdfaccess.ashx?url= sliding and rolling. A load cell connected to the ball shaft enables the friction force to be monitored continuously. For each entrainment speed, the friction force is measured with the disk moving faster than the ball and vice versa at the same entrainment speed and slide roll ratio"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003217_tmag.1985.1064247-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003217_tmag.1985.1064247-Figure2-1.png",
+ "caption": "Fig. 2. Determination of the electromagnetic torque in the machine.",
+ "texts": [
+ " For example, between nodes d and e, the constant value of radial f lux density is given by The nodal value for node e is then given by a weighted average o f the radial components on either side of the node, thus Br(ee) = b e - e f ) Br(de) + (8d - e,) Br(ef) ( 6 ) ed - ef With a reasonable discretisation, the degree o f accuracy by both methods is approximately equal, and, hence, results presented later in this paper have used the simpler second method for economy. CALCULATION OF TORQUE The conventional method of determining instantaneous torque in an electrical machine is to compute the force on individua1:stator conductors by a Maxwell stress integration F- = 4 B.H ds f (7) about an arbitrarily defined contour enclosing the conductors in each slot, for instance contour C shown i n Fig. 2. This has two disadvantages: f i rst the l ine integral calculation when performed for a machine with many slots over a range of operating conditions will require a considerable amount of central processor time and, secondly, for accurate results a fine discretisation along the contour is required, since the values o f B and H are both derivatives of the solution potential. 2431 As an efficient alternative to this, the azimuthal force on the conductor (and hence the torque) can be determined using Fe = Br 1, I (8) Tests have shown that the average value of radial flux density over one slot p i tch on a surface lying midway between the rotor radius and the stator bore (surface S in Fig. 2) gives a satisfactory value for 8,. This value is easily computed from the total flux per slot pitch obtained by a Simpson's rule integration over each slot p i tch and interpolating the radial component of f lux density a t each point from nodal values using the shape functions of the elements. FLUX DENSITY AND .TORQUE CALCULATIONS SYNCHRONOUS MOTOR FOR A HIGH FIELD PERMANENT-MAGNET Figure 3 shows the transverse cross-section o f a high field 4 pole permanent-magnet synchronous machine. The configuration shown with non-radial rare-earth permanent-magnets has many advantages, particularly that the rotor flux per pole exceeds the flux passins through any one magnet"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000595_1.2828771-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000595_1.2828771-Figure1-1.png",
+ "caption": "Fig. 1 A scliematic drawing of 6-axis CNC hobbing machines",
+ "texts": [
+ " The general gear mathematical model can also be applied to the design and manufacturing of spur, helical, worm gears and noncircular gears. Results shown in this study also provide the industry an important software for design, analysis, and manufacturing of various types of gears. A 6-axis CNC hobbing machine can be used to manufacture different types of gears owing to the movement of its axes with multi-degree of freedom. The generation process of gears by applying a CNC hobbing machine is quite complex. Figure 1 presents a schematic drawing of a 6-axis CNC hobbing machine, where axes X, Y and Z are the radial axis, the tangential axis, and the axial axis, respectively; axes A, B and C are the hob swivel axis, the hob spindle axis and the work table axis, respec tively. However, in today's CNC hobbing machines, axes A and Y are for set-up only and rotational ratio between axes B and C is a constant. Some machines allow an interrelationship between axes X and Z; therefore, today's CNC hobbing machines are 3- axis machines"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003564_05698190490500743-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003564_05698190490500743-Figure5-1.png",
+ "caption": "Fig. 5\u2014Face with single-row spiral grooves.",
+ "texts": [
+ "0 \u00b5m, and p3 = 2.02 MPa. That means, with the sealing-oil pressure disturbance, this seal can keep the radius r\u2217 of the interface between oil and gas nearly unchanged by means of adjusting the oil-film thickness and peak pressure. Therefore, this double-row spiral groove seal is very stable under oil-pressure disturbance. Wang, et al. (7) present another kind of noncontacting, zeroleakage face seals with single-row spiral grooves. The face with single-row spiral grooves and two annular dams is shown in Fig. 5. The pressure distribution of oil film over the interface and the axial force balance of the primary ring are shown in Fig. 6. Now the theoretical analyses aimed at Fig. 6 are carried out, in which the D ow nl oa de d by [ U ni ve rs ity o f C al if or ni a Sa nt a C ru z] a t 2 1: 31 1 0 O ct ob er 2 01 4 Fig. 6\u2014Pressure distribution of oil film over the interface and axial force balance of primary ring. assumptions are the same as those for the face seals with doublerow spiral grooves in a splay pattern"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003802_chicc.2006.280612-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003802_chicc.2006.280612-Figure1-1.png",
+ "caption": "Fig. 1 Quarter-car model for active suspension control design. The motion equations of the system are",
+ "texts": [
+ "ey Words: Active suspension, Quarter-car model, LQR, Backstepping suspension analysis and design. The simplified quarter-car model is depicted in Fig. 1. Suspension system is a complex dynamic system. To improve the performance of suspension system is the main way to dissipate the road disturbance and improve the ride and safety. Passive suspension system being used prevalently in traditional cars can only store and receive outside energy but not be able to adapt the variance of the road condition and outside stimulating, so the improvement of the car performance is restricted greatly. Since Dr. Federspiel-labrosse brought forward the idea of active suspension firstly in 1955, a long list of research papers were published in this area"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001423_s1350-4533(99)00095-8-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001423_s1350-4533(99)00095-8-Figure7-1.png",
+ "caption": "Fig. 7. The model of the common insertion (white ellipse) of the lumbrical (LUM) and radial interosseous (rIOSS) on the EDL hood (gray shell) is illustrated. A portion of the proximal phalanx is omitted for clarity. The instantaneous location of the insertion is approximated as the sum of",
+ "texts": [
+ " Point p \u2192 lat,union gives coordinates of the union of the lateral bands on the terminal extensor slip with respect to coordinate-system-3. Flexion of the distal joint qDIP is assumed to translate this point along the middle phalanx in the direction of x \u2192 3. coordinates of lumbrical origin (p \u2192 LUMo,straight) may be estimated with respect to the metacarpal bone (coordinate-system-0). Flexion of the finger joints {qMCPf, qPIP, qDIP} allows excursion of the tendon as determined previously (Fig. 4). This excursion is assumed to translate the lumbrical origin proximally by (Dp \u2192 LUMo). the EDL (Fig. 7). For simplicity, the kinematics of the extensor hood are initially calculated with respect to the first phalanx, coordinate-system-2. In this frame of reference, it is reasonable to assume the portion of the EDL central slip in contact with the first phalanx does not translate due to flexion or abduction of the MCP joint. When the finger is straight, a point on the extensor hood is given by ( 2p \u2192 hood,straight). Flexion of the PIP and the DIP joints can drag this point distally along the proximal phalanx"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001031_oceans.2003.178583-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001031_oceans.2003.178583-FigureI-1.png",
+ "caption": "Fig. I . Foimation configuration",
+ "texts": [
+ " Horizontal following 4. Dive to the source 5. Marking the source Additionally several other discrete states are defined for the maneuver. These are fault condition or malfunction (in one, various vehicles or in the formation control); intermediate formation establishment (necessary to redefine the formation ) and return to survey. This last state corresponds to the return to the survey either after the 1. Survey 50 The state of the formation in three phases of the mission is depicted in the next figure. In the initial Survey state, the ASV executes a \u201csweeping\u201d pattem. The 3 AUVs follow the surface vehicle at a small fixed depth and maintain the vertical projection of the boat at the middle of the triangle formed by them. Upon the trace detection of the phenomenon by one of the A W s , this AUV reduces velocity and changes direction to a perpendicular to its previous movement. If the plume is confirmed the formation distortion introduced by the detecting vehicle is perceived by the others. This change of formation can also be reflected in the increase of acoustic pings since the navigation system adapts itself to the global dynamics (with the previous very steady state movements there is no need for faster update rates)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002293_an9962101489-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002293_an9962101489-Figure1-1.png",
+ "caption": "Fig. 1 Optical arrangement for measurements with the flow-through cell: D, detector; FC. flow-through cell; MI, mirror; MC, monochromator; SM, sensor membrane consisting of the polymer support and the nitrite sensitive coating; S, sample solution.",
+ "texts": [
+ " Apparatus Fluorescence excitation and emission spectra a s well as response curves of the sensing membranes were measured on an Aminco (Rochester, NY, USA) SPF 500 spectrofluorimeter equipped with a 250 W tungsten halogen lamp as a light source and linked to an HP 98 15A desk calculator (Hewlett-Packard, Avondale, PA, USA) and a red sensitive detector. Response curves were recorded by placing the membranes in a flowthrough cell to form one wall of the cell. Excitation light hit the sensor membrane from outside (after passing the glass wall of the flow cell and the polyester support), and fluorescence was detected at an angle of 55\" relative to the incident light beam (Fig. 1). Buffer solutions and buffered sample solutions were pumped through the cell at a flow rate of I .S ml min-1. When studying the response of the sensing membranes, excitation and emission wavelengths were set to 550 and 590 nm, respectively. The absorption spectra of the sensor membranes were measured on a Shimadzu (Kyoto, Japan) UV-2 10 1 -PC photometer. All experiments were performed at 22 f 2 \"C. The sensing scheme used in this work is based on the use of lipophilic derivatives of rhodamine B which dissolve very well in polymeric matrices because of their high solubility in organic Table 1 Composition of anion seiisor membranes MI-M5 Metnbrane Dye Polymer BPP Plasticizer M1 KBOE PVC 200 mol% NPOE M2 RBOE PVC 100 mol% NPOE M3 RBOE PVC 40inol% NPOE M4 RBOE PVC 40mol% DOS MS KBOE PVC-Co 40tnol% NPOE solvents, plasticizers, and plasticized polymers"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001429_robot.1989.100102-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001429_robot.1989.100102-Figure2-1.png",
+ "caption": "Figure 2. Graphical Simulation Model for the DIGITS System (Version 1).",
+ "texts": [
+ " I11 EXAMPLE MECHANISM In order to demonstrate the significance of the Compact-Dual LP method, in this section, the Original LP, Compact-Primal LP, and Compact-Dual LP methods are applied to solve the force distribution problem of the DIGITS System. A brief description of the DIGITS System will be presented first, followed by the approach taken to obtaining the known components of the equations of the force distribution problem. Simulation results and computation times for each of the three L P methods will be highlighted and compared at the end of this section. A. The DIGITS System As shown in Fig. 2, the DIGITS System (Version 1) has 4 fingers, each with 3 degrees of freedom as is slightly larger than the human hand. All of the joints are revolute with each driven by a brushless DC motor and belt-drive system, which is under development at OSU. This system is targeted for loads of a few pounds. The maximum joint torque limits of each finger are approximately: (32) (33) (34) -0.9 nt-m 5 5 0.9 nt-m, -1.8 nt-m 5 r2 5 1.8 nt-m, -1.8 nt-m 5 r3 5 1.8 nt-m. For simplicity of presentation only two fingers are first used to manipulate a very dense 2 lb"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002581_robot.1996.503837-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002581_robot.1996.503837-Figure1-1.png",
+ "caption": "Figure 1: An experimental planar five-link walking biped.",
+ "texts": [
+ " Kajita and his coworkers [6, 71 built a series of bipedal robots with control algorithms that minimize excursions of the robots\u2019 bodies, but their goal was to simplify the dynamics of the system, rather than create a smooth walk. Blajer and Schiehlen [8] have examined impact-free walking of a complex biped from a theoretical point of view. None of the foregoing studies have aimed a t the the development of smooth walking over uneven ground. 0-7803-2988-4/96 $4.00 0 1996 IEEE 578 2 Experimental hardware We believe that experimental verification of our cont,rol strategies is essential, and consequently, we have constructed a planar bipedal robot to serve as the test bed for our research. Figure 1 shows the machine's basic structure, which consists of a pair of legs joined to a body. Each leg pivots on a rotary hip joint at the body and contains a prismatic lower leg joint which acts to change the leg length. Pneumatic cylinders drive the extension and retraction of the lower legs. We selected pneumatic cylinders for this application because of their favorable force to weight ratio. Unfortunately, continuous control of pneumatic syskms is notoriously difficult (see [9], for example), and we found it necessary to implement a nonlinear observer-based cont,rol scheme to obtain reasonable performance under walking conditions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000497_a:1008966218715-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000497_a:1008966218715-Figure6-1.png",
+ "caption": "Figure 6. Determination of the local map.",
+ "texts": [
+ " Each obstacle region Mk is included in the present local map, if the following condition is satisfied: |pc \u2212 m\u0304k | < dc + \u03bbd , where pc is the center position of the mobile robot, \u03bbd = \u03bb\u03041k cos1\u03b8 if 1\u03b8 < tan\u22121 \u03bb\u03042k \u03bb\u03041k \u03bb\u03042k sin1\u03b8 otherwise , and 1\u03b8 = |\u03b8\u0304k \u2212 6 (mk \u2212 pc)|. \u03bbd here represents the span of the obstacle region from m\u0304k along the direction of the vector pc \u2212 m\u0304k and 1\u03b8 represents the orientation difference between the major axis of Mk and the vector pc\u2212m\u0304k . Consequently, if1\u03b8 is zero degree, then the obstacle region is completely aligned with the vector pc\u2212 m\u0304k and \u03bbd becomes equal to \u03bb\u03041k . On the other hand, if 1\u03b8 is 90\u25e6, then \u03bbd becomes equal to \u03bb\u03042k . As shown in Fig. 6, if the above condition is satisfied, then all or part of the obstacles included in Mk may be located inside the active circle. Then, each obstacle region in the local map is put to the test in Step 3 to determine which of Mk\u2019s are associated with the present clustered regions. Whereas the clustered regions are newly defined every sampling time, the obstacle regions are created, updated or deleted depending on whether each obstacle region is associated with any of the clustered regions. Consequently, Step 3 determines which obstacle regions are associated with the current clustered regions and update their parameters accordingly"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000895_(sici)1097-4563(199603)13:3<177::aid-rob5>3.0.co;2-p-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000895_(sici)1097-4563(199603)13:3<177::aid-rob5>3.0.co;2-p-Figure1-1.png",
+ "caption": "Figure 1. Configuration of a 4-link planar mechanism in singular posture (dead point), in this case dI2 = 0.",
+ "texts": [
+ " In the example of a 3-DOF planar RRR manipulator, there exist three virtual 2- DOF manipulators. The determinates of each virtual 2-DOF manipulator Jacobian matrix are given by where For 3-DOF manipulator, where the manipulator end-effector position is given, 1-DOF of redundancy will change arm configuration through self-motion (homogeneous part of solution), just as with a 1-DOF 4-link planar mechanism. For a 4-link planar mechanism there exists a singular posture depending upon each link length. The singular posture, called Dead point, occurs at the arm configuration shown in Figure 1. In the case of dead point of the arm configuration, one of the dI2, d23, d,, must be zero. The 1-DOF of redundancy in the 3-DOF manipulator is lost in this case, thus the minimization of joint torques cannot be performed through self-motion, and only the manipulator end-effector demand will be guaranteed. Velocity-minimization can be executed even in this singular posture to guarantee the manipulator end-effector demand. Thus, in the case of no extra DOF in the redundant manipulator, the weighting 300 $ 200 100 0 - I \u2018 0 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003893_0301-679x(83)90004-x-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003893_0301-679x(83)90004-x-Figure3-1.png",
+ "caption": "Fig 3 Testing set-up for (a) fiat and (b) spherical laminates. 1-rollers; 2-cage; 3-hardened steel plate; 4-spherical laminate; 5-double-convex adapter; 6-concave supporting plates",
+ "texts": [
+ " Standard extensometer amplifiers were used with the testing machines to give resolutions of 0.25/am actual displacement per mm on graph paper. Signals from two transducers (Fig 2Co)) were averaged to reduce the adverse influence of machining errors and of the asymmetry of motion of the left and right driving screws of the testing machines. The shear stiffness of the flat samples were measured under variable compression. To alleviate friction effects, a standard set of rollers in a cage and hardened and ground end plates (Fig 3(a)) were used to apply compression force Pz. In measuring shear ka and torsional k~/stiffness of the spherical samples, two identical samples with intermediate solid double-convex lens-shaped block were used for a similar purpose (Fig 3(b)). Compression load on the spherical samples was applied through solid concave lens-shaped blocks. When the double-sample set was used, as in Fig 3, the measured value of compression stiffness was kz]2, and of shear and torsional stiffness, 2k= and 2k7, respectively. Experimental results Compression stiffness Compression stiffness versus specific compression load Pz = Pz]A, where A is the surface area of the sample, is shown in Fig 4 in a double4ogarithmic scale. Compression stiffness is expressed in terms of differential (local) = Hardness was measured on standard cylindrical samples (2.54 cm diameter, 1.27cm high) made from a given rubber"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003927_1.1828069-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003927_1.1828069-Figure1-1.png",
+ "caption": "Fig. 1 Map of model rough ball surface measured with an optical profiler",
+ "texts": [
+ " In the SLIM method a similar disk was used, but with a much thinner silica layer, of thickness 130 nm. For the smooth surface tests, two types of ball were studied. The majority of tests employed highly polished AISI 52100 steel ball, with root mean square roughness, Rq of 12 nm, but a smooth steel ball coated with chromium was also studied, having similar roughness. The thickness of the chromium layer was 1\u20132 mm. Model rough surfaces were prepared by sputtering a series of parallel, chromium ridges on the surface of a smooth steel ball. The ridges, shown in Fig. 1, were of approximately sinusoidal shape, about 165 nm high, had a wavelength of 60 mm, and were oriented transverse to the rolling direction. The Rq parameter for this artificial roughness was 71 nm. For the isotropic rough surface tests, a rough AISI 52100 steel ball, manufactured by early withdrawal from the ball-finishing process, was used, with roughness parameter Rq579 nm. A 3D plot of the surface of the rough steel ball obtained with an interference microscope is shown in Fig. 2. 2.2 Friction Measurement"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001925_84.388115-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001925_84.388115-Figure9-1.png",
+ "caption": "Fig. 9. one-half hour of operation. Photograph of the rotating shaft near the bearing after approximately",
+ "texts": [
+ " The vibration resulted form the asymmetry of the stator and the clearance between the wheel shaft and the chassis and it generated an elliptical movement. Fig. 8 shows the track of the wheel contact point that was measured by a noncontact, 2-dimensional displacement meter. The short diameter (5 pm) of the elliptical track was equivalent to the bearing clearance. This elliptical movement moved the microcar in one direction. IV. DISCUSSION The car ran at a maximum speed of 100 \"/sec, which does not seem fast, but it may be too fast for a 1/1OOOth scale car. Therefore, wear of the rotating parts could be quite severe. Fig. 9 shows the condition of the rotating shaft near the bearing after approximately one-half hour of operation. The contact point of the shaft is damaged because of the wear of the bearing. Lubrication, bearings, and other means of reducing the friction are difficult to apply to micro-systems. To study the effect of lubricant for micro-rotating wheel bearings, an experiment was conducted using a high speed video camera. Fig. 10 shows the experimental setup. Lubricant was supplied to the bearing while the wheels were rotating"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003067_bf00126072-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003067_bf00126072-Figure1-1.png",
+ "caption": "Fig. 1. Start Circular path with vertical forces.",
+ "texts": [
+ " It should be pointed out that any torques and forces to be realized at the gripper modify only the Ci (s)-terms, which for free trajectories contain only gravitational forces and, for force or torque controlled trajectories, contain additional contact forces or torques. ~1 76 I ~r Q 0 ~ (D 0 C ~ ,0 0 .2 0 .4 0 .6 0 .8 1 ,0 ~ .2 ;, 4 Sq ua re o f pa th v el oc it y (~ 2) ~0 0 .2 0~ 4 0~ 6 0 .8 l. O 1 ,~ 1 .4 0 .2 0 .4 0 .6 0 .8 1 .0 1 .2 1 .4 -n i! i 2 9 > r, > > Z Z The path planning optimization as presented above has been applied to various cases with forces at the gripper. Figure 1 gives an example for a circular path parallel to the y - z plane, being tracked by a manipulator with five revolute joints. Figure 2 shows the results of the time-optimization applying the method of [9]. The zero force case (F = 0) includes three critical points (saddle points). The maximum velocity curve as well as the time optimal curve are symmetrical with respect to the s = 0.5 point. Applying a negative force, which means pushing down the gripper (Figure 1), results in the manipulator starting very slowly due to the load of the additional force ( - F). Only one critical point remains, and the deceleration is performed as slowly as the acceleration. On the other hand, lifting the gripper with ( + F ) (Figure 1) allows for a large acceleration and deceleration because a positive force aids a steep slope at the start of the trajectory by partly compensating the gravity forces. But such a force in the upward direction brings down the velocity at the highest path point for s = 0.5. Figure 3 gives an illustration of the joint torques necessary to realize the timeoptimal trajectories of Figure 2. Each block of six diagrams contains the torques of the five joints in the first five diagrams and the time-minimum solution of Figure 2 in the sixth diagram"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003926_1.338581-Figure30-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003926_1.338581-Figure30-1.png",
+ "caption": "FIGo 30 First-order transition curveso",
+ "texts": [],
+ "surrounding_texts": [
+ "Numerical Methods Dan Bloomberg, Chairperson\nThe Preisach model and hysteretic energy losses I. D. Mayergoyz and G. Friedman Electrical Engineering Department and Institute for Advanced Computer Studies. University of Maryland. College Park, Maryland 20742\nUsing Preisach's model, general expressions for hysteretic energy losses are derived. These expressions are valid for arbitrary (not necessarily periodic) variations of magnetic field. Moreover, these expressions are given in terms of Preisach's function as well as in terms of experimentally measured \"first-order transition curves.\" A formula is also found which relates the hysteretic energy losses for arbitrary field variations to the losses ocurring for certain periodic variations of magnetic field. This formula allows for easy measurement of hysteretic losses occurring for arbitrary field variations.\nINTRODUCTION\nA hysteresis phenomenon is associated with some ener gy dissipation which is often referred to as hysteretic energy losses. The problem of determining hysteretic energy losses is a classical one. The solution to this problem has long been known for the case of periodic (cyclic) variations of magnet ic field. In that case, the hysteretic energy losses are equal to the area enclosed by a hysteresis loop resulting from a peri odic field variation. However, energy dissipation is a contin uous process, and it occurs for arbitrary (not necessarily periodic) variations of magnetic field. The problem of com puting hysteretic energy losses for the above general case has remained unsolved. A solution to this problem would be of both theoretical and practical importance. From the theo retical point of view, the solution of the above problem will allow for the calculation of internal entropy production, I which is a key point in the development of irreversible ther modynamics of hysteretic media. 2 It will also lead to the expression for the energy stored in the magnetic field which eventually may help to find electromagnetic forces in hyster etic media. 3 From the practical viewpoint, the solution of the problem may bring new experimental techniques for the measurement of hysteretic energy losses occurring for arbi trary field variations.\nIt should not be surprising that the solution of the prob lem has been known only for the case of periodic variations of magnetic field. The reason is that for cyclic field variations the expression for energy losses is easily derived using only the energy conservation principle; no knowledge of actual hysteresis mechanisms is required. The situation is much more complicated when an arbitrary variation of magnetic field is considered. Here, the energy conservation principle alone is not sufficient and an adequate model of hysteresis should be employed in order to arrive at the solution of the problem. It turns out that Preisach's hysteresis model is very well suited for this purpose.\nIn this paper, Preisach's model is used to derive general expressions for hysteretic energy losses. These expressions are given in terms ofPreisach's function as well as in terms of experimentally measured \"first-order transition curves.\"\nFurthermore, a formula is found which relates the hysteretic energy losses occurring for an arbitrary field variation to the losses occurring for certain periodic field variations. This formul.a leads to a simple technique for the measurements of hysteretic losses occurring for arbitrary variations of mag netic field.\nIt has been emphasized before4-7 that Preisach's model is purely phenomenological and can be used for the math ematical description of hysteresis of any physical nature. For this reason, the expressions for hysteretic energy losses de rived in this paper are quite general and valid regardless of the physical nature of hysteresis. The only requirement is that such hysteresis can be described by Preisach's model.\nEXPRESSIONS FOR HYSTERETIC ENERGY LOSSES\nTo make the exposition more or less self-contained, the main facts concerning Preisach's model will be briefly re viewed. The detailed information on this subject can be found in Refs. 4--8. For the sake of generality, we shall de scribe Preisach's model in a purely mathematical form. In this form, any hysteresis nonlinearity can be characterized by an input u(t) and an output J(t). In magnetic applica tions u (t) is the magnetic field, while f( t) is the magnetiza tion.\nConsider an infinite set of operators r a{3 which are rep resented by rectangular loops on the input-output plane (Fig. 1). Along with these operators, consider a weight fune-\n3910 J. Appl. Phys. 61 (8),15 April 1987 0021-8979/87/083910-03$02.40 \u00ae 1987 American Institute of Physics 3910 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37",
+ "tiontt (a,p) which is often called Preisach's function. Then, Preisach's model is given by\nf(t) = J J fl (a,/J)r afJ u(t)dad{J. (1)\na>{3\nFor hysteresis nonlinearities with closed major loops the functiontt{a,p) has a finite support within some triangular area T on the a-{3 plane.\nThere is a one-to-one correspondence between opera tors YaP and points (a,/J) on the half-plane a>p. Using this fact, it can be found that, at any instant oHime, the triangle T is subdivided into two sets (Fig. 2): S + (t) and S - (t) con ~isting of points (a,/3) for which Yapu(t) = 1 and YaP u(t) = - 1, respectively. The interface L(t) between S + (I) andS - (t) isa staircase line the vertices of which have a and {3 coordinates coinciding with local maxima and mini ma of u (t) at previous instants of time. The final (attached to the line a = f3) link of L(t) is horizontal and moves up when the input increases, and it is vertical and moves from right to left when the input decreases. For any given hystere sis nonlinearity, Preisach's function tt(a,{3) can be found from the set of \"first-order transition (reversal) curves\" at tached to the limiting ascending branch (Fig. 3). The appro priate formulas are\nF(a,/J) = fa -laP' (2)\n( ,{3) - 1 a2F(a,fJ) fla ---\n2 8a8p (3)\nIt turns out (see Refs. 5 and 8) that the integral in Eq. (1) can be directly expressed in terms of F(a,/J) as follows:\n1 n\nlet) = -2F (ao,/3o) + k~l [F(ak,Pk_d - Fad 3k)]'\n(4)\nwhere {ak} and {Pk} are decreasing and increasing se quences of a and /3 coordinates of interface vertices, respec tively, and n is the number of horizontal links of L (t) .\nIt has been proved in Ref. 6 that two properties consti tute necessary and sufficient conditions for the representa tion of a hysteresis nonlinearity by Preisach's model. These properties are the \"wiping-out property\" and the \"con gruency property.\" For the discussion of those properties see Refs. 6 and 7. In the sequel, we shall assume that these prop erties are satisfied, and Preisach's model is valid.\nNow we are equipped to proceed to the derivation of expressions for hysteretic energy losses. We begin with the case when a hysteresis nonlinearity is represented by a rec-\n3911 Jo AppL Phys., Vol. 61. Noo 6, j 5 April 1967\ntangular loop shown in Fig. 1. If a periodic variation of input is such that the whole loop is traced, then the hysteretic energy loss for one cycle equals the area 2(a - [3), enclosed by the loop. It is dear that the horizontal links of the loop are fully reversible and, for this reason, no energy losses occur when these links are traced. Thus, it can be concluded that only \"switching-up\" and \"switching-down\" result in energy losses. It is apparent (on the physical grounds) that there is symmetry between these two \"switchings\" and, consequent ly, the same energy losses (equal to a - {3) occur for each of these switchings. The product f.i (a,/3) Ya/3 can be construed as a rectangular loop with output values equal to \u00b1 /-L (a,/3). For this reason, switchings up or down of such a loop win result in energy loss p(a,{3)(a - /3). According to Prei sach's model (1), any input variation is associated with swi tchings up or down of some rectangular loop f.i (a ,/3) Yap. Thus, the energy loss occurring for an arbitrary input vari ation is naturally equal to the sum of energy losses resulting from the switchings of rectangular loops during this input variation, Since we are dealing with a continuous ensemble of rectangular loops, the above summation should be re placed by integration. Thus, if n denotes the region of points (a,p) for which the corresponding rectangular loops were switched during some input variation, then the hysteretic energy loss Q for this input variation is given by\nQ = I f j.l(a,f3)(a - {3) da d[3. (5)\nII\nA typical shape of the region n is shown in Fig. 4. It is clear from this figure that n can be always subdivided into a trian gle and some trapezoids, The trapezoids, in turn, can be rep resented as differences of triangles. Thus, if the integral (5) can be evaluated for any triangular region, then this integral can be easily determined for any possible shape of fto It makes sense to compute the values of integral (5) over var-\nI. 00 Mayergoyz and G. Friedman 3911 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37",
+ "ious triangles. Using these values, hysteresis losses can be easily found for any variation ofinput. In the case when n is a triangle, the integral (5) can be easily evaluated in terms of F(a,{:J) , which is related to the \"first~order transition curves\" by formula (2). The derivation proceeds as follows: It can be verified that\n(j2 --[F(a,{:J) (a - {J) ] (ja8p\n= a 2F(a,p) (a _ (3) + aF(a,{:J) oa a/3 ap\n_aF~(:.....-a.:!....J3.:.-) . (6) da\nUsing Eqs. (3) and (6), we find\n2jt(a,/3) (a _ (3) = 8F(a.{3) _ aF(a,/J) 8P oa\n(j2 - -- [F(a.{3)(a - {3) ]. (7)\naa 8{3\nNow, consider a triangle T(u+,u_) swept (see Fig. 5) dur~ ing the input increase from u _ to u +. According to Eq. (5), such input variation is associated with the losses\nQ(IL,U+) = f f p,(a,/3)(a - (3)da d/3 T(,,+,u ,.)\n= i~+ ([ jt(a,{J)(a - /3) d/3 )da\n= iU ,+ (Lu + p(a,/3)(a -fJ)da )d/3. (8)\nSubstituting Eq. (7) into Eq. (8), performing the integra tion and taking into account that F(a,a) = 0, after simple transformations we find 1 rru , lU' Q(u_,u+) = - 2\" Uu_ F(a,u_ )da + \"_ F(u+.{3)d{3\n- (u+ - u_ )F(U+,U_\u00bb) . (9)\nIt can be shown that the derived expressions for hysteretic energy losses are consistent with the classical result: the hys teretic energy losses for any cyclic input variation equal the area enclosed by the loop resulting from the cyclic input\n3912 J. Appl. Phys., Vol. 61, No.8, 15 April 1987\nvariation. The proof is omitted. Consider a cyclic variation of input from u _ to u + and back to u _. During the monotonic increase of input from u_ to u+, the final horizontal link of L(t) sweeps the triangle T( u + ,u ._ ). On the other hand, during the monotonic de crease of input from u + to u _, the final vertical link of L (t) sweeps the same triangle. Thus, it can be concluded that, for any loop, the hysteretic losses occurring along ascending and descending branches are the same:\n(10)\nNext, we shall use expression (10) to find the formula which relates hysteretic energy loss occurring for an arbi trary monotonic input variation to certain cyclic hysteretic losses. Suppose that the input u(t) increases monotonically from some minimum value u_ and reaches successively some values uland U2, (u2>u I). We are concerned with the hysteretic loss Q( u I,U2 ) occurring during the input variation between U I and u2\u2022 For the above input variation, we have: n = T(u2,u_) - T(ul,u_). Consequently,\nQ(ul,UZ) = Q(U_,U2) - Q(u_,u 1). (11)\nUsing Eq. (10), losses Q(u_,u 2 ) and Q(u_,u 1 ) can be ex~ pressed in terms ofcycliclosses Q(u_,u l ) = ~Q(U_,Ul) and Q(U_,U2) = ~Q(U_,U2)' where Q(u_,u j ) and Q(u_,u2) are cyclic losses for periodic input variations between u_ and U 1, u_ and U z, respectively. Using this fact, from Eq. (11) we find\n(12)\nThe last formula can be useful from the experimental point of view because it is much easier to measure cyclic losses than losses occurring for nonperiodic input variations.\nACKNOWLEDGMENTS\nThe reported research was motivated by the question raised by Professor H. A. Haus during the talk given by the first author at MIT. This research is supported by the U.S. Department of Energy, Engineering Research Program (contract no. DE-AS05-84EH13145).\n11. Prigogine, Introduction to Thermodynamics of Irreversible Processes, 2nd edition (Wiley, New York, 1961). 2J. S. Cory and J. L. McNicols, J. Appl. Phys. 58, 3282 (1985). 'P. Penfield, Jr. and H. A. Haus, Electrodynamics of Moving Media (MIT, Cambridge, MA, 1967). 4M. Krasnoselskii and A. Pokrovskii, Systems with Hysteresis (Nauka, Moskow, 1983). 51. D. Mayergoyz, J. Appl. Phys. 57, 3903 (1985). \"T. Doong and I. D. Mayergoyz, IEEE Trans. Magn. MAG-21, 1853 (1985). 71. D. Mayergoyz, Phys. Rev. Lett. 56,1518 (1986). 81. D. Mayergoyz, IEEE Trans. Magn. MAG-22, 603 (1986). 9J. A. Barker, D. E. Schreiber, B. G. Huth, and D. H. Everett, Proc. R. Soc. London Ser. A 386,251 (1983).\nI. D. Mayergoyz and G. Friedman 3912 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003019_ajassp.2005.626.632-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003019_ajassp.2005.626.632-Figure5-1.png",
+ "caption": "Fig. 5: Experimental Device Components, where; (1)",
+ "texts": [
+ " 4), is the resultant of vertical components of the elementary forces due to pressure, by integrating the normal force it gives: n max maxF p cos dp p r cos d 2p r sin \u03b3 \u03b3 \u2212\u03b3 \u2212\u03b3 = \u03a6 = \u03a6 \u03a6 = \u03b3 (3) Where, db rd / cos= \u03c6 \u03c6 and - is the half of the central angle of the deformed zone. Also from the same figure, we can obtain: 2 3 4 2 (D d )b sin 1 2r 16r \u2212 \u03b3 = = \u2212 (4) The friction force due to ring deformation at assembly is: Ff=\u00b5 D3Fn (5) Replacing equations (2,3,and 4) in equation number (5), we get the developed expression of the friction force: 2 3 4 3 4 3 2 D d (D d ) Ff 2 D rE 1 1 4r 16r \u2212 \u2212 = \u03c0 \u2212 \u2212 (6) The validity of expression 6 ( 2 3 4 3 4 3 2 D d (D d ) Ff 2 D rE 1 1 4r 16r \u2212 \u2212 = \u03c0 \u2212 \u2212 ) was tested with an experimental device (Fig. 5), which was used for obtaining the experimental results. The Ram has five different sizes of sockets or grooves to increase the possibility of testing different number of O-ring sizes (Fig. 5). Each groove is designed for a specific diameter, The ram and cylinder geometry is characterized by the values of the diameters, both diameters are clearly shown in Fig. 3 and 4, in our case the cylinder diameter D3 = 28.03 mm, the inside ram diameter d4 having five different sizes, in our case (d4 = 21.41, 21.45, 21.59, 21.74 and 22.10 mm), all of these sizes were tested and the obtained results are indicated in Fig. 7 (in absence of the pressure), in which each size has its proper value of friction, Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003587_1.2125971-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003587_1.2125971-Figure1-1.png",
+ "caption": "Fig. 1 The TriVariant robot",
+ "texts": [
+ " As a result, all configurations can be found by solving the end polynomial equation 1\u20137 . The complexity of the polynomial approach depends upon the geometry of the object and proper choice of elimination techniques. The numerical approach can be used to find the solutions close to the initial estimate using root search algorithms or optimization techniques 8 . This paper deals with the forward position analysis of the 3-DOF parallel mechanism module which forms the main body of a newly invented hybrid robot named TriVariant Fig. 1 9 . The research interests will be focused on finding the number of its forward position solutions in comparison with the corresponding results of the Tricept 10\u201312 . As shown in Fig. 1, the module consists of a base and a mobile platform connected by three kinematic chains limbs . Two are identical UPS limbs and the other is a UP limb whose output link is fixed with the mobile platform. Here, U, P and S represent the universal, prismatic, and spherical joints respectively, and P denotes that the corresponding joint is active. The TriVariant can be considered as a simplified version of the Tricept robot, achieved by integrating one of the three active limbs into the passive one while keeping the required type and degrees of freedom"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002460_63.85913-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002460_63.85913-Figure5-1.png",
+ "caption": "Fig. 5. Current space vector\\ and control error stripe for phase R",
+ "texts": [
+ " Therefore one can only give a continuous power density spectrum for them which could be obtained by a Fourier transform of the auto correlation function. However, in this paper the analysis in the frequency domain is not persued further. Besides the mathematical advantages of the space vector representation a very clear description of the system behavior is made possible. E.g., the deadbands around the phase current reference values are transformed into stripes lying perpendicular to the respective phase axis (see Fig. 5 , there shown for phase R). The common area of these stripes (i.e., the control errors of all three phases are smaller than the deadband width) results in a hexagon being characteristic for three-phase ON-OFF controllers (see Figs. 7, 17). The tip of the reference value space vector lies in the center of the hexagon. Basically one could define arbitrary areas instead of the hexagon if the control concept is based on a space vector representation of the control error (e.g. , such as in [2]). Contrary to such areas only the hexagon guarantees the full use of the allowable phase current control error"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003979_s10035-005-0210-5-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003979_s10035-005-0210-5-Figure2-1.png",
+ "caption": "Fig. 2 Schematic view of a light ray consisting of numerous refractions propagating through the granular medium",
+ "texts": [
+ " The autocorrelation function is then given by [13,14]: gE(t1, t2) = \u221e\u2211 n=1 P(n) < exp(j ( n(t2) \u2212 n(t1))) > (16) where P(n) is the fraction of the total scattered intensity in the light paths involving n scattering events. This quantity is related to the geometry of the experiment. The quantity n(t2) \u2212 n(t1) is the phase difference of the scattered electric field between the time t1 and t2, associated with a given path involving n scattering events. The average < ... > is calculated over all the paths involving n scattering events. Figure 2 is a simplified geometrical view of the random walk of a photon across the different beads, composed of travels across beads, intersticial media, and refraction or reflection.Any displacement of matter will contribute to a variation of the optical length between t1 and t2. This could include not only the displacement of the centers r\u03bd of the spheres, but also rotations of nonspherical beads or deformations of the beads. For the sake of simplicity, we will ignore such effects in the following discussions, although they are not expected to be systematically negligible"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001376_s0967-0661(99)00084-2-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001376_s0967-0661(99)00084-2-Figure7-1.png",
+ "caption": "Fig. 7. The scheme of the developed gyrodine with 5-DOF electromagnetically suspensed rotor, the #exible gyroshell's preloaded ball bearings, a gear stepping drive and an electromagnetic damper on the gyrodine precession axis.",
+ "texts": [
+ " The mathematical model of manoeuvring spacecraft takes into account: f the controlled orbital motion of the spacecraft mass center; f the spatial angular motion of the spacecraft frame as a carrying rigid body; f movements of #exible solar array panels (P 1 , P 2 ) and receiving}transmitting antennas (A 1 , A 2 ), see Fig. 2, about the spacecraft body by means of 2-DOF suspension with the gear stepping drives; f movements of the moment dyrocomplex in the form of the `2-SPEEDa-type minimum-excessive scheme, see Fig. 5; moreover, the model of each gyrodine describes } the nonlinear dynamics of the control laws for current loops in the gyrorotor's 5-DOF electromagnetic suspension, see Fig. 7; } the proper gyrorotor rotation dynamics with regard to its static and dynamic unbalance; } the #exibility of gyroshell's preloaded ball bearings; } the #exibility, dead band and kinematic defects in the gear; } the dynamics of a stepping motor with a breaking up the step and an electromagnetic damper on the gyrodine precession axis that takes into account the dry friction torque; f the moment gyrocomplex \"xation on the spacecraft body by means of a vibration-absorbing frame; f external torques * aerodynamic, gravitational and magnetic; f the #exible-viscous \"xation of the optical telescope construction (in Ritchey}Chretien's optical scheme) on the spacecraft body, by means of a vibration-absorbing frame P, see Fig",
+ " Some results, obtained by the software system DYNAMICS, on the vibrational analysis of the image motion dp z (t) onto the light detector Pi, while being sub- jected to the rotation frequency of all four statically unbalanced gyrodine's rotors in ball bearings and without a vibro-absorbing frame for the moment gyrocomplex \"xation on the body of the spacecraft, are given in Fig. 9. The vibration amplitude on velocity dQ p z of this image at the gyrorotor's nominal rotation frequency is equal to &0.4 arcsec/s. The use of the gyrorotor's 5-DOF electromagnetic suspension (see Fig. 7) in each gyrodine and the placement of the moment gyrocomplex on the spacecraft body by means of a vibro-absorbing frame made it possible for a vibration amplitude of&0.005 arcsec/s to be attained at this rotation frequency for all gyrorotors. Let the spacecraft's spatial rotation manoeuver in an inertial reference frame be de\"ned by the vector of Euler}Krylov's angles a(t)\"Ma i (t)N\"Ma x (t), a y (t), a z (t)N in sequence M3-1-2N, in addition to the quaternion K(t). The concrete problems of the precise control of the spacecraft's spatial rotation manoeuver and control of the process of the opto-electronic observation are formulated as follows: f to transfer the attitude control system's state vector precisely along a program from the position ai\"a(t i ) (a quaternion Ki), xi and bi, which is given at initial time t i \"0: ai\"M"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003895_j.1749-6632.1985.tb18426.x-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003895_j.1749-6632.1985.tb18426.x-Figure8-1.png",
+ "caption": "FIGURE 8. Anticipated mechanism of oxaloacetate-CO, exchange by coupling to the transport of Na' ions over the membrane.",
+ "texts": [
+ " One would expect, therefore, that the decarboxylases are reversible systems, as well, if the same principles of vectorial energy coupling were valid. Decarboxylation reactions are completely irreversible when catalyzed by the soluble en~ymes.~'.]' These systems, however, do not imitate in full the physiological situation where the decarboxylation is coupled to the transport. Since this coupling could be essential, we have studied the reversal of decarboxylation reactions with the decarboxylases reconstituted into proteoliposomes (unpublished results). A schematic view of this kind of system is shown in FIGURE 8. When oxaloacetate is decarboxylated to pyruvate and CO,, a Na' ion gradient is developed over the membrane which in the reverse reaction could drive the carboxylation of pyruvate to oxaloacetate. The carboxylation was demonstrated by the incorporation of I4CO, into oxaloacetate. This incorporation was strictly dependent upon the Na+ gradient since no [\"C] oxaloacetate was formed in the presence of the Na' ionophore monensin. Similar observations have also been made with methylmalonyl-CoA decarboxylase containing proteoliposomes which catalyzed the isotopic exchange between ''C0, and malonyl-CoA by mediation of a Na' gradient"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003151_j.triboint.2004.10.004-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003151_j.triboint.2004.10.004-Figure2-1.png",
+ "caption": "Fig. 2. Schematic of a journal bearing.",
+ "texts": [
+ " Consequently, the problem mentioned above can be summarized as the following optimization problem in discrete: Min: J\u00f0p\u00de Z 1 2 fpg\u00bdK fpgK fpgT\u00f0\u00bdB \u00f0fuagC fubg\u00de C \u00bdF flgK \u00bdW f _hgK fqg\u00deK fmgTfpg (11a) s:t: \u00bdC fpgK \u00bdM flgC fdgK fng Z 0 (11b) flgTfng Z 0; flgR0; fngR0 (11c) fmgTfpg Z 0; fpgR0; fmgR0 (11d) where {m} is the Lagrangian multiplier vector. Letting dJ(p)/dpZ0 in Eq. (11a) and making use of Eqs. (11b) and (11d), the following complementary problem is obtained: \u00bdK fpgK \u00f0\u00bdB \u00f0fuagC fubg\u00deC \u00bdF flgK \u00bdW f _hg K fqg\u00deK fmg Z 0 (12a) \u00bdC fpgK \u00bdM flgC fdgK fng Z 0 (12b) flg T fng Z 0; flgR0; fngR0 (12c) fmgTfpg Z 0; fpgR0; fmgR0 (12d) The problem described by Eqs. (12a) and (12d) can be solved by many methods. In the present paper, the Lemke method is used. A journal bearing rotating with velocity u is shown in Fig. 2, where qZx/R, cZR0KRi/R0ZR., 3Ze/c. The unit length load support in the x and y directions are: wy ZK \u00f0qout 0 pR cos w dw (13a) wx Z \u00f0qout 0 pR sin w dw (13b) The total film load support is: w Z ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi w2 x Cw2 y q (14) and the load support angle is: f Z tanK1 wx wy (15) . (a) T0aZT0bZ6; (b) T0aZT0bZ5; (c) T0aZT0bZ2; (d) T0aZT0bZ0.5; (e) In the present paper, we use the dimensionless parameters: PZpc2/(huR2), HZh/c, T0aZt0ac/(huR), TLaZ tLac/(huR), TaZtac/(huR), UaZua/U, KaZkaR/c, L\u00f0i\u00de a Zl\u00f0i\u00dea =U \u00f0iZ1; 2; aZa; b\u00de, TZtU/R, QZqs/(cU), where UZuaCub"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000595_1.2828771-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000595_1.2828771-Figure5-1.png",
+ "caption": "Fig. 5 Heiipoid gears' tooth surface",
+ "texts": [
+ " In equation (39), parameter p is the screw parameters of the worm. Parameters u determines the location of current point A (or A') on the generating line; where u = \\MA\\ (or M = | M ' A ' | for the generating line II) as shown in Fig. 4. By applying the general gear mathematical model developed here, the Helipoid gears' tooth surface can be specified. By substituting equations ( 3 7 ) - (40) into Eqs. ( 4 ) - ( 6 ) and Eqs. (28) and (29), the tooth surfaces of the Helipoid gear are obtained and shown in Fig. 5. Conclusion Hobbing machines are widely used in industry for manufac turing different types of gears. Developing of 6-axis CNC hob bing machines makes the manufacturing of gears more efficient and flexible. Besides, it allows for novel type of gears to be developed. In this paper, we have proposed a general gear math ematical model based on the cutting mechanism, geometry of worm-type hob cutter and the theory of gearing. The developed general gear mathematical model can be applied not only to the gears manufactured by the conventional hobbing machines, but also to the noncircular gears and new type of gears with new manufacturing processes"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002864_s0924-0136(03)00811-2-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002864_s0924-0136(03)00811-2-Figure5-1.png",
+ "caption": "Fig. 5. CAD models (1) and metallic parts (2).",
+ "texts": [
+ " The technical curve of the process is shown in Fig. 4. The air in the mould is removed with the counter-pressure reduction (A\u2013C), then the pressure raised in the lower chamber for mould filling (C\u2013D). After mould filling, it is necessary to have a holding pressure period (E\u2013F) to enhance the casting solidification under the pressure and to obtain highly sound metallic castings. The alloy for the moulding shell casting was Al-alloy (6\u20138% Si, 0.45% Mg, 0.21% Fe). After pouring and cleaning, the desired metallic parts were obtained. Fig. 5 shows the CAD model and the metallic parts manufactured using this process. Investigation and control of accuracy were necessary in the process of rapid manufacturing of metallic parts. The main errors of parts included error from CAD model to SLS prototype and the error from the SLS prototype to metallic parts. The sintering process of the SLS polymer prototype, which included developing CAD model and sintering polymer powder, was one of the main sources of errors. Data of computer-aided slicing of the CAD model and sintering software system caused some error between the CAD model and SLS prototype"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003153_146441905x63322-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003153_146441905x63322-Figure1-1.png",
+ "caption": "Fig. 1 Side view of a gantry crane",
+ "texts": [
+ "n this article, the development of a gantry crane operator-training simulator, including all the earlier mentioned components, is presented. The aim of this article is to present an example of methods used in the development of the separate areas of a training simulator. Keywords: gantry crane, real-time simulation, user training, motion platform, dynamic modelling Gantry cranes are used in a harbour environment to move containers between the pier and the ships. The crane (Fig. 1) consists of three main parts that move in relation to the pier and each other: the gantry moves along the rails in the direction of the pier and the trolley moves along the rails attached to the gantry perpendicular to the pier. The spreader, used to grab the containers, is attached to the trolley via cables and carries out the hoisting movement by winding and unwinding the cables. Traditionally, gantry crane operators are trained while operating actual cranes with real cargo in harbours. This might cause dangerous situations, decrease work efficiency, and even become very expensive if mistakes occur"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002315_iros.1996.570801-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002315_iros.1996.570801-Figure3-1.png",
+ "caption": "Figure 3. Modeling of the wheeled inverted pendulum.",
+ "texts": [
+ " It also has a rate gyroscope in the upper part of the body and a rotary encoder on the motor axis as sensors. The concept of cooperative transportation by Proc. TROS 96 0-7803-3213-X/96/ $5.00 0 1996 IEEE Figuye 1. The st icture of the wheeled inverted pendulum. move - Wheeled inverted pendulum two wheeled inverted pendulums is presented in Figure 2. In Figure 2, each inverted pendulum exerts a force on the object and, from the opposite point of view, it sustains the same magnitude of an external force. So' we consider a model of the wheeled inverted pendulum which is subjected to an external force (Figure 3). We assume that the external force is applied on the body of the wheeled inverted pendulum at the axle height horizontally for simplicity. The equations of motion of this model are as follows. 3. Control method -9, - 9 2 (32 -E- X = We assume 8, and e, are so small that we can approximate el2 = 0, sin 8, = e,, and cos 8, = 1, and linearize Equations (1) and ( 2 ) about the point of equilibrium. Assuming also that the dynamics of the applied external force is such that - 0 0 8 , , A = a, a2 - 0 we obtain the state equation and the output equation of the system as follows"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.6-1.png",
+ "caption": "Figure 3.6. Finite rotation of an antenna panel.",
+ "texts": [
+ " Euler's theorem has shown that the components of the rotation tensor, hence also those of the rotator, may be found by construction of the basis transformation matrix A in (3.123b ). Thus, the angle and the axis of the equivalent Euler rotation may be obtained from (3.89) and (3.90) when the initial and final orientations of the body reference frame are known. This will be illustrated next. Example 3.9. A certain mechanism is to be designed to rotate an antenna panel of a spacecraft about a point 0 so that the side facing the i 1 direction in the initial configuration ultimately must face the initial i 3 direc tion in the terminal configuration shown in Fig. 3.6. Determine the equivalent Euler rotation required for the design. Solution. The spatial frame >>>>>< >>>>>>: \u202660\u2020 S2: \u00b32 \u02c6 g cl ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 cml2 \u00b3 \u00b4 \u00b32 2\u2026\u00b32\u2020 _\u00b32 2 \u2021 1 cml2 u2 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 cml2 \u2026s1\u2026t\u2020 s2\u2026t\u2020\u2020 \u2021 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 cml2 \u00b31 8 >>>>>>>< >>>>>>>: \u202661\u2020 where u1 and u2 are the control torques applied to the pivot point of each pendulum, \u00b0 \u02c6 m=M , i\u2026\u00b3i\u2020 \u02c6 \u00b0 sin \u00b3i, l is the length of the pendulum, and k and g are spring and gravity constants. We assume that \u00b0 > 0 is exactly known and the angles \u00b31 and \u00b32 are the only measured states. It is further assumed that c, l and k are unknown constants. Unlike in Shi and Singh (1992) where s1\u2026t\u2020 and s2\u2026t\u2020 are assumed to be sinusoidal, we consider general time-varying and bounded horizontal displacements s1\u2026t\u2020 and s2\u2026t\u2020 which are unknown. The system (60) \u00b1 (61) is not in the form (11), mainly because the vector \u00ae elds depend non-linearly on the unmeasured states _\u00b31 and _\u00b32. Inspired by our recent work (Jiang and Kanellakopoulos 2000), non-linear transformations are needed to bring the system (60)\u00b1 (61) into a decentralized system that depends aYnely on the unmeasured states. (Such a transformation was implicitly used in Mazenc et al. (1994).) As stated in Remark 2, extension to the practical tracking case follows trivially from results in practical output regulation. D ow nl oa de d by [ G eo rg e M as on U ni ve rs ity ] at 2 2: 03 0 1 Ja nu ar y 20 15 Non-linear transformations : For each i \u02c6 1; 2, de\u00ae ne xi1 \u02c6 \u00b3i, yi \u02c6 xi1 and xi2 \u02c6 e \u00b0 cos \u00b3i _\u00b3i \u202662\u2020 As it can be directed checked, (60) and (61) were transformed into ~S1: _x11 \u02c6 e\u00b0 cos y1 x12 _x12 \u02c6 e \u00b0 cos y1 cml2 u1 \u2021 g cl e\u00b0 cos y1 y1 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 cml2 e\u00b0 cos y1 \u00a3 \u2026s1\u2026t\u2020 s2\u2026t\u2020 \u2021 y1 y2\u2020 8 >>>>>< >>>>>: \u202663\u2020 ~S2: _x21 \u02c6 e\u00b0 cos y2 x22 _x22 \u02c6 e \u00b0 cos y2 cml2 u2 \u2021 g cl e\u00b0 cos y2 y2 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 cml2 e\u00b0 cos y2 \u00a3 \u2026s1\u2026t\u2020 s2\u2026t\u2020 \u2021 y1 y2\u2020 8 >>>>>< >>>>>: \u202664\u2020 Notice that all non-linerities in ~S1 and ~S2 now depend only on the outputs y1 \u02c6 \u00b31 and y2 \u02c6 \u00b32. Observer design: For any L1; L2 > 0, introduce two new variables \u00b9i \u02c6 cml2\u2026xi2 Lixi1\u2020; for i \u02c6 1; 2 \u202665\u2020 and let \u00b9\u0302i be an estimate of \u00b9i which is given as _\u0302 \u00b9i \u02c6 Li e\u00b0 cos yi \u00b9\u0302i \u2021 e \u00b0 cos yi ui \u202666\u2020 Now, for each i \u02c6 1; 2; denote \u00b1i as the observation error \u00b1i \u02c6 \u00b9i \u00b9\u0302i \u202667\u2020 By direct computation, we have _\u00b1i \u02c6 Li e\u00b0 cos yi \u00b1i \u2021 \u00bfi\u2026t; y1; y2\u2020; for i \u02c6 1; 2 \u202668\u2020 where \u00bf1 and \u00bf2 are de\u00ae ned by \u00bf1 \u02c6 cml2L2 1 e\u00b0 cos y1 y1 \u2021 mgl e \u00b0 cos y1 y1 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 e \u00b0 cos y1 \u2026s1\u2026t\u2020 s2\u2026t\u2020 \u2021 y1 y2\u2020 \u202669\u2020 \u00bf2 \u02c6 cml2L2 2 e\u00b0 cos y2 y2 \u2021 mgl e \u00b0 cos y2 y2 ka\u2026t\u2020\u2026a\u2026t\u2020 cl\u2020 e \u00b0 cos y2 \u2026s1\u2026t\u2020 s2\u2026t\u2020 \u2021 y1 y2\u2020 \u202670\u2020 Like in Shi and Singh (1992), assume that a\u2026t\u2020 is an unknown time-varying function. Then, it is easily veri\u00ae ed that there exists an unknown constant p\u00a4 > 0 such that j\u00bfij \u00b5 p\u00a4\u2026j\u2026y1; y2\u2020Tj \u2021 1\u2020; for i \u02c6 1; 2 \u202671\u2020 To facilitate the controller design, denote \u00b7\u00b1i \u02c6 \u00b1i=p\u00a4. It then follows that _\u00b7\u00b1 i \u02c6 Li e\u00b0 cos yi \u00b7\u00b1i \u2021 1 p\u00a4 \u00bfi\u2026t; y1; y2\u2020; for i \u02c6 1; 2 \u202672\u2020 On the other hand, both xi1 subsystems in (63) and (64) can be rewritten as _yi \u02c6 e\u00b0 cos yi cml2 \u00b9\u0302i \u2021 e\u00b0 cos yi cml2 p\u00a4 \u00b7\u00b1i \u2021 Li e\u00b0 cos yi yi \u202673\u2020 So, for the practical output regulator design, we obtain the decentralized systems (72), (73) and (66) with partialstate measurements (yi; \u00b9\u0302i). Also, notice that the unknown coe cient 1=\u2026cml2\u2020 appears in the front of \u00b9\u0302i. Fortunately, this situation can be handled as in Marino and Tomei (1995, } 7.3) or Krstic\u00c2 et al. (1995, Chapter 8). We also borrow ideas from Marino and Tomei (1995, } 7.3) to avoid overparametrization . Noting that e \u00b0 \u00b5 e\u00b0 cos yi \u00b5 e\u00b0 for all yi, a direct application of our decentralized adaptive scheme in } 5.1 gives decentralized dynamic output feedback control laws of the form _\u0302pi \u02c6 \u00b6i\u00bci p\u0302i \u2021 \u00b6i\u2026Li \u2021 L 1 i \u2020 e\u00b0 cos yi y2 i \u2021 \u00b6i e\u00b0 cos yi w2 i2 @#i1 @yi \u2021 4 @#i1 @yi \u00b3 \u00b42 \u20210:5 @#i1 @yi \u00b3 \u00b44 \u00c1 ! \u202674\u2020 ui \u02c6 ci2wi2 \u2021 Li e\u00b0 cos yi #i1 \u2021 @#i1 @yi Li e\u00b0 cos yi yi \u2026Li \u2021 L 1 i \u2020yi e\u00b0 cos yi _\u0302pi p\u0302i e2\u00b0 cos yi wi2 @#i1 @yi \u2021 4 @#i1 @yi \u00b3 \u00b42 \u20210:5 @#i1 @yi \u00b3 \u00b44 \u00c1 ! \u202675\u2020 where #i1 \u02c6 ci1yi L3 i yi L 1 i e 4\u00b0 cos yi yi p\u0302i\u2026Li \u2021 L 1 i \u2020yi, wi2 \u02c6 \u00b9\u0302i #i1, and c11 \u00b6 0:5 \u2021 L 1 2 e4\u00b0, c210:5 \u2021 L 1 1 e4\u00b0, ci2 \u00b6 0, \u00bci > 0 and \u00b6i > 0, 1 \u00b5 i, j \u00b5 2, are design parameters. For simulation uses, take \u00b0 \u02c6 0:01, m \u02c6 g \u02c6 l \u02c6 k \u02c6 1 and c \u02c6 2. Also, take \u00bci \u02c6 \u00b6i \u02c6 1, L1 \u02c6 1, ci1 \u02c6 10 and c2j \u02c6 1 for 1 \u00b5 i, j \u00b5 2. For comparisons, as in Shi and Singh (1992), we take a\u2026t\u2020 \u02c6 sin \u20265t\u2020, s1\u2026t\u2020 \u02c6 sin \u20262t\u2020 and s2\u2026t\u2020 \u02c6 2 \u2021 sin \u20263t\u2020. Figure 2 shows the time histories of the angles \u00b31 and \u00b32 and the torques u1 and u2."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001253_rnc.754-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001253_rnc.754-Figure1-1.png",
+ "caption": "Figure 1. Formation geometry of ith and \u00f0i 1\u00deth aircraft.",
+ "texts": [
+ " Furthermore, these results confirm that when the wing aircraft is properly positioned in the vortex of the lead aircraft, it experiences reduction in its required flight power. The organization of this paper is as follows. Section 2 presents the mathematical models of the UAVs. A design model of the UAV is described in Section 3. The robust formation control system and observers are designed in Section 4. Section 5 present a stability analysis of the closed-loop system. Control of two UAVs and simulation results are presented in Section 6. Let us consider close formation of \u00f0m\u00fe 1\u00de aircraft. The formation geometry of the \u00f0i 1\u00deth and ith aircraft is shown in Figure 1. It is assumed that the Earth is flat and not rotating. Oi is the center of mass of the ith aircraft, where \u00f0i \u00bc 0; 1; . . . ;m\u00de: OiOi 1 is the separation vector. In this study, the coordinate systems for the ith aircraft of interest are the following: the ground axes system \u00f0Sgi\u00de (not shown in the figure), the local horizontal system \u00f0Shi\u00de with its origin fixed on the aircraft (axes Xhi; Yhi; Zhi), the wind axes system Swi (axes #iwi; #jwi; #kwi) obtained from Shi by three successive rotations of heading angle (velocity yaw) \u00f0wi\u00de; flight path angle (velocity pitch) \u00f0gi\u00de; and bank angle (velocity roll) \u00f0mi\u00de; and the body axes system \u00f0Sbi\u00de (not shown in the figure) obtained from Swi by two rotations, the sideslip angle bi and the angle of attack ai: Readers may refer to Etkin [23] and Miele [24] for the notation and the matrix equations relating various system of axes"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002541_s0039-9140(03)00408-9-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002541_s0039-9140(03)00408-9-Figure2-1.png",
+ "caption": "Fig. 2. Flow cell prototype II: (a) general view of the flow cell; (b) cross-section of the flow cell showing the different cell components.",
+ "texts": [
+ " Finally, the Baytron P layer was coated with 100 l of the ion-selective membrane with the composition shown in Table 1. The resulting carbon composite all-solid-state K+-ISEs (area: 0.07 cm2) can thus be described as follows: SS/CC/Baytron P/ISM. The electrodes were conditioned in 0.1 M KCl for at least 1 day prior to measurements. The electrodes were kept in 0.1 M KCl conditioning solution between measurements. The flow cell prototype II containing four all-solid-state ISEs is illustrated in Fig. 2. In a piece of PMMA, four holes were drilled in the same plane for the in situ fabrication of the four electrodes. The flow-channel (2 mm inner diameter) was then drilled in the center perpendicularly to the electrode plane (Fig. 2a). Standard connections were used to connect the cell to the flow system. The cell dimensions were 15 mm (outer diameter) and 12 mm (flow-channel length), and the total cell volume was ca. 37 l. 2.4.2. In situ fabrication of the all-solid-state K+-ISEs K+-selective membranes (ISMs) were cast in each of the four drilled holes, as shown in Fig. 2. After drying (overnight) the ISM forms a membrane (diameter: ca. 0.8 mm) that separates the flow channel from the internal solid contact of the ISE (Fig. 2b). The composition of the ISM is shown in Table 1. The internal solid contact of the ISE was prepared by solution casting of the aqueous dispersion of PEDOT (Baytron P) (Fig. 2b). After drying, the Baytron P layer formed a film on the ISM. The internal contact was completed by inserting the carbon composite paste (described in Section 2.3) in contact with the Baytron P layer. The CC paste was compressed with the stainless steel screw, which was connected to the mV-meter (Fig. 2b). The resulting all-solid-sate K+-ISEs were kept dry between measurements. For comparison, also macroscopic electrodes (area: 0.03 cm2) were made in the same way. However, these were kept in 0.1 M KCl solution between measurements. These all-solid-sate K+-ISEs were of the same type as the macroscopic electrodes described in Section 2.3 (SS/CC/Baytron P/ISM) but the ISM and Baytron P layers were cast in reverse order. The potentiometric measurements were performed with a homemade multi-channel mV-meter connected to a PC for data acquisition",
+ " Nevertheless, the present all-solid-state K+-ISEs were still working after more than one month when kept in conditioning solutions between measurements (Fig. 3). Poor adhesion of Baytron P to substrates such as gold and glassy carbon (GC) disk electrodes prevented the use of the Baytron P dispersion in the construction of the electrodes for the flow cell prototype I. This resulted in the development of the flow cell prototype II, where the electrodes were prepared in situ, as described in Section 2 (Fig. 2). The cell volume of prototype II was ca. 37 l, which was limited mainly by technological factors in the construction of the flow cell at the laboratory workshop. Since the ISM is cast directly in the cell body, the electrodes are not removable, which has to be considered in the choice of materials. However, this feature together with the mechanical fixation of the solid contact by the screw prevents leakage and loose contacts between electrode parts, and ensures easy handling of the cell-electrode device",
+ " When the CC/Baytron P is covered by the ISM, the impedance plot is dominated by a large high-frequency semicircle due to the bulk resistance in parallel with the geometric capacitance of the plasticized PVC-based ion-selective membrane, as shown in Fig. 4c. The impedance features are typical for solid-contact ISEs with a well-defined ion-to-electron transduction mechanism [12]. The results indicate that the all-solid-state K+-ISEs work properly and that there is contact between the different electrode layers. However, the adhesion between CC and Baytron P was found to be relatively weak and was improved by mechanical fixation in the flow cell prototype II (Fig. 2). Calibration plots of the all-solid-sate K+-ISEs obtained in KCl solutions with 0.1 M NaCl constant background is shown in Fig. 5. The calibration plots were recorded from 10\u22121 to 10\u22125 M and then back to 10\u22121 M KCl. The slope of the linear part of the calibration curve for miniaturized electrodes (10\u22121 to 10\u22125 M) was 56.4 \u00b1 0.7 mV per decade (n = 2); and for the macroscopic electrodes (10\u22121 to 10\u22124 M) it was 55.3 \u00b1 0.9 mV per decade (n = 3). The wider linear ranges and better slopes for miniaturized all-solid-state K+-ISEs in comparison with macroscopic electrodes may in this experiment be due to different placements of the reference electrode"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0003286_0167-2789(86)90076-x-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003286_0167-2789(86)90076-x-Figure5-1.png",
+ "caption": "Fig. 5. The subtemplate .La(V\u00b0o) c,Xe'H, a) Simple substrips. K6 can be on either edge. b) Case A, n, o odd. c) Case B, nko even. d) Flip right-hand (twisted strip to left). K6 can lie on either edge.",
+ "texts": [
+ " ako_ v S\u00b0(l,\u00b0o) cAe~ H is a strip bounded on one side by K~ and containing K 0 in its interior. Since w~ (resp. wOwO) and w 0 agree except in one letter, S\u00b0(1,\u00b0o) consists of k 0 - 1 ' s imple ' strips connected subintervals of I x and Iy and jo ined end to end, together with one ' spl i t t ing ' strip in which the loops of K~ and K o pass a round opposi te sides of ~ H - F r o m the discussion before propos i t ion 2.3, in case A K o goes to the left and K6 to the right, while the oppos i t e occurs in case B. See fig. 5. In this figure we also pe r fo rm a simple isotopy which reveals that Ph. Holmes/Knottedperiodic orbits in suspensions of Smale's horseshoe 17 Za(p\u00b0o) is merely a strangely embedded copy of O'~H, and therefore induces a map on its branch line, Jo, homeomorph ic to f~ itself. This reflects the fact that f f o l j \u00b0 repeats the bifurcation sequence of f~ll ' in miniature ' ; section 2.3. Note that, although we have moved the twisted strip of figs. 5b, c over to the left, the words of the knots on ",
+ " In fact w 1 = WOWS, as the reader can check, so that K1 is a 2k0-periodic orbit, as required. The subtemplate construction also makes it clear that K 1 is the boundary of a M~Sbius band centered on K o and thus is a cabling: fig. 7. Finally, the number of crossings of K 1 over K 0 is 2c 0, inherited from the 'extrinsic' self-crossings of \u00a3a(r\u00b0o/2) due to its strange embedding, plus one crossing for each 'intrinsic' twist of o . \u2022 . ~ ( 1 ) k / 2 ) . i.e. for each strand of K o on the right of Xe\" n (in case B this includes the crossing in the splitting piece, cf. fig. 5c). Thus l ( K 1, K0) = 2c 0 +Y0, as claimed. It 2 0 Ph. Holmes / Knotted periodic orbits in suspensions of Smale's horseshoe With a little more information on the kneading invariant corresponding to the 'mo the r ' knot K 0 we can go further: Theorem 4.3. Let v \u00b0 ko = v0 * + - be an admissible, *-factorizable, 2k0-periodic kneading invariant corresponding to a k0-periodic itinerary ~0 with an odd number Y0 of y ' s in each finite acyclic block w 0. Let the horseshoe knot K 0 corresponding to w 0 have crossing number c o and let the it inerary of the critical po in t cor responding to v o have n o y ' s in the first k o entries"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0001033_robot.1995.525419-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001033_robot.1995.525419-Figure1-1.png",
+ "caption": "Figure 1 Arm-hand meclianisin.",
+ "texts": [
+ " Kliatib has poiiitecl oiit t,liiLt, t,lie iiiert,ia of tlic IEEE International Conference on Robotics and Automation 2 Basic Equation 2.1 Arm-Hand Mechanism Arm-hand niecliaiiisnis, discusscd iii t,liis p q m . coiisist. of ~ 1 1 1 s iLiid iiiidt,ifiiigerc:d haiids. assiiiiied to liavc six DOF. Tlic iiiiiltifiiigered 1i;~iids liave tlireo fiiigers. aiid each fiiigcr hits t,lir<:e joiiits t,o iiiitkc frictioiial poiiit, c:oiit,ac:t,. Tlic assiiiiiIhoiis oil tjlic liaiicts a rc sitiiie as iii [3]. Iii t,liis sec:t,ioii. basic cqn;ttioiis of i t r i i i -h id iiicdiaiiisiiis. sliowii iii Fig. 1. i ~ r o dc:scril)ccl. Tlic: iioiiieiiclatiires in t~liis p p c r tire as follows: The itrills CB : Base coordinitt,e fraiiic. the origin OB E.i : A r m (:oordiiiat~~. fraiiio. t,lir, origin 0.4 CH : Haiitl coordiiiat,e franic. tlic origin OH C, : Coiit,act, point, of %-t,li fii~gert~ip. i = I , 2. 3 pF, E R3 : Positioii of C , froiii OB \u201cI,,, E R 3 : Posit,ion of C, from Oa p F , E R 3 : Positioii of C , froni OH 11 E R3 : Positioii of OH froiii OB p 4 E R 3 : Posit~ion of 0 . ~ froiii OB H E R3 : Position of OH froiii 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-FigureA.2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-FigureA.2-1.png",
+ "caption": "Figure A.2. Scalar component representations of a vector v in a plane and in space.",
+ "texts": [
+ "L The sum and difference of two vectors and their parallelogram interpretation show ing the commutative property of addition. ticularly their geometrical interpretation in a parallelogram construction, are useful. These are shown in Fig. A.! for the reader's review. Any vector v can be identified uniquely by its three perpendicular, direc ted projections {vd = (v 1 , v2 , v3 ) upon the three mutually perpendicular axes x 1, x 2 , x 3 (or x, y, .:::) of a rectangular Cartesian coordinate system, as shown in Fig. A.2. The positive directions of these coordinate lines, which are assumed to be arranged in a right-hand sense as usual, are themselves vector lines identified by three unit vectors, say, e1 , e2 , e3 . The set { ed is called a basis, and the three orthogonal projections v~ are known as the scalar com ponents of the vector v referred to {ek}\u00b7 Thus, when vis referred to this basis, it has the unique representation 1 v = I vkek = v1 c 1 + v2e2 + v3 e3 , k~! (A.l) which is illustrated in Fig. A.2. This means that only vectors equal to v can have the same scalar components when referred to { ek }. That is, u = v if and The Elements of Vector Calculus 355 only if the corresponding scalar components uk and vk are equal when u and v are referred to { ek}: uk = vk fork= I, 2, 3. This rule for equality of two vectors u and v referred to the same basis vectors ek is used often in applications to determine unknown components in vector equations. The same vector v may be referred to any other basis { e~ }, say. Of course, its scalar components { vk} in this basis will be different from those in (A.l ), but its representation has the same form as (A.l ), namely, v = L~~,vkek. The foregoing geometrical description of the scalar components shown in Fig. A.2 implies that the magnitude of a vector v is equal to the square root of the sum of the squares of its scalar components: (A.2) A.l.l. The Dot Product The dot product of two vectors u, v is a scalar defined by u . v = uv cos< u, v > (A.3) where u= lui, v = lvl, and cos",
+ " The position vector of the top of the antenna from the station F is denoted by X. Another frame cp = { 0; ek} has the absolute velocity v0 =6e 1 -4e2 +7e3 ft/sec at an instant t0 when ek = lk. The angular velocity and angular acceleration of cp relative to tP at time t0 are given by ffi = 4e 1 + 2e2 - 3e3 rad/sec, Compute the first and second time rates of change of X as seen from cp at the instant of interest. Does v 0 affect the results? .w Problem 4.6. I, 320 Chapter 4 4.7. Consider the hinged joint and slider block shown in Fig. 2.20. Let frame 1 = { B; p, y, k} be fixed in the slider block B, as shown, and introduce another frame 2 = { B; a, p, A} fixed in the hinged yoke of the connecting rod AB so that A is parallel to!. (a) Determine as functions of y the angular velocity of the rod relative to B and the absolute angular velocity of B in the frame t:P = { F; ik} shown in Fig. 2.19. (b) What is the angular speed of the rod relative to the slider block? (c) What is the absolute angular velocity of the rod referred to frame 1"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.2-1.png",
+ "caption": "Figure 4.2. A vector U (t) referred to a preferred and to a moving frame.",
+ "texts": [
+ " The terms \"preferred\" and \"moving\" will be used only in the simple relative sense described above; and, whenever it may be convenient, we may reverse our choice of labels for the two frames and achieve parallel results. We shall assume that all observers employ the same time reference, i.e., all observers use the same standard clock. Let the preferred frame be denoted by
. Zt = P(fian -k flbn). (2) From (2), it is possible to obtain the general sliding condition, but it is quite complicated. Since the desired knot trajectory lies in the normal direction to the tissue, we shall only consider the symmetric shown in Figure 5. At the equilibrium, the force and moment equations about p and p' are c=e(P = PI = ,927 7 = 71 = 7 2 , F1a = F2a), as (4) (5) Coulomb\u2019s law states the sliding occurs when It can be further simplified to (7) 1 1 tanp tany > 2P, --- which results in the following sliding condition (8) tany 2p tany + 1 o < p < tan-\u2019( )"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002191_6.2002-1261-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002191_6.2002-1261-Figure2-1.png",
+ "caption": "Figure 2. Finite element model of a coiled tube.",
+ "texts": [
+ " Material Properties Both the coiled and Z-folded models are polyethylene tubes with a diameter of 3.82 inches and a thickness of 0.006 inches. The values of the tube's Young\u2019s modulus, Poisson's ratio, and density used are 25,000 psi, 0.25, and 0.033 lbm/in3, respectively. The inflation is air at 70o F with a molecular weight of 28.97 lbm/lbmole. The gas flows in at one end of the tube with an inflation mass flow rate ( )/ dtdm of t\u00d71.0 lbm/sec. The finite element model for the coiled tube packaged configuration is displayed in Figure 2. It consists of seven CVs and is created by employing a simple Archimedean spiral equation, 0 rar += \u03b8 . The symbol a represents a constant, \u03b8 is the sweep angle, and 0 r is the initial radius as shown in Figure 2. The nodes are created starting at 0=\u03b8 and 0 rr = and continue up to a user defined length. The unwinding of the coiled tube is shown in Figure 3. The volume and pressure as a function of time for each CV are shown in Figures 4 and 5, respectively. The tube is fully deployed at time 0.35 sec. The pressure is 8 psi, which induces a hoop strain of 10 %. The finite element model for the Z-folded tube packaged configuration is displayed in Figure 6. Inflated shapes of the Z-folded tube in various stages of deployment are shown in Figure 7"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003974_tia.2005.863911-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003974_tia.2005.863911-Figure1-1.png",
+ "caption": "Fig. 1. Flux densities in the air gap.",
+ "texts": [
+ " A block diagram to suppress time delay, caused by eddy current, sampling period, and current regulation is proposed. Radial force and speeds of the shaft are also estimated, and used as feedback signals. The effectiveness on improving response and damping of radial positioning is shown both theoretically and experimentally. In the analysis, three conditions are assumed. 1) Magnetic saturation can be neglected. The permeability in the iron is infinite. 2) Flux distribution in the air gap confronting a stator tooth is uniform and fringing flux is negligible. 3) The rotor surface is magnetically smooth. Fig. 1 shows definitions of coordinates \u03b1 and \u03b2, angular position \u03b8, and air-gap flux densities B24t(\u03b8) in the air-gap area confronting stator teeth. With flux density B24t(\u03b8) of each stator tooth as a function of an angular position \u03b8, radial forces F\u03b1 and F\u03b2 in the 0093-9994/$20.00 \u00a9 2006 IEEE perpendicular \u03b1- and \u03b2-axes are the sum of the difference of flux density squared, written as F\u03b1 = Sa 2\u00b50 180\u25e6\u2211 \u03b8=0\u25e6 [ B2 24t(\u03b8) \u2212 B2 24t(\u03b8 + 180\u25e6) ] cos \u03b8 (1) F\u03b2 = Sa 2\u00b50 180\u25e6\u2211 \u03b8=0\u25e6 [ B2 24t(\u03b8) \u2212 B2 24t(\u03b8 + 180\u25e6) ] (\u2212 sin \u03b8) (2) where \u00b50 is the permeability in free space"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003258_51.35577-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003258_51.35577-Figure1-1.png",
+ "caption": "Figure 1. Motion of a particle in a periodically excited two-well potential.",
+ "texts": [
+ " Several general examples wil l be briefly discussed in this section, wi th references listed that enable the reader to explore each of the examples in more detail. Examples that wil l be discussed are: a particle in a two-wel l potential, a conical pendulum, the population dynamics equation, and the Van der Pol oscillator. The subject of fractals wil l be introduced wi th a brief look at the Mandelbrot and Julia sets. Particle in a Two-well Potential. One of the simplest chaotic systems t o envision is a ball (or particle) in a two-wel l potential, as illustrated in Fig. 1. The ball can be in either of the t w o wells, each of which is an equilibrium state when the base is at rest. Now imagine that the base is vibrated wi th a certain period and wi th an amplitude sufficient t o cause the ball t o go from one well t o the other. It turns out that, under certain conditions, the ball wil l jump back and forth wi th a fixed period such as ABAB ..., or AABAAB ..., but for other conditions the pattern is chaotic, that is, there is no periodicity in the sequence of As and Bs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002038_ls.3010080402-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002038_ls.3010080402-Figure1-1.png",
+ "caption": "Figure 1 Schematic representation of a contact between sliding surfaces",
+ "texts": [
+ " A system for wear prediction in lubricated sliding contacts should encompass all such cases and integrate them into one logical structure. THE MODEL All theories that predict wear rates start from the concept of a true area of contact that is determined by the plastic deformation of the highest asperities on the contacting surfaces. During relative motion of contacting surfaces there takes place a continuous process of making and breaking of the adhesive junctions resulting from the interactions between surface asperities. This is shown, schematically, in Figure 1. Adhesive wear in dry contacts Lubrication Science 8-4, July 1996. (8) 318 0954-0075 $10.00 + $4.00 31 9 T.A. Stolarski : A System for Wear Prediction in Lubricated Sliding Contacts The real area of contact is the instantaneous sum of the areas of all junctions. The central assumption of the model is that it is possible to relate the volume of material removed, V; in the sliding distance, L, to the real area of contact,A, Archard\u2019s model In the model proposed by Archard,\u2019 it is assumed that the junction consists of a circle of radius r, the corresponding area of contact being ma"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure2-1.png",
+ "caption": "Fig. 2. The deformation of an in\u00aenitesimal element whose deformed con\u00aeguration is a rectangular parallelepiped.",
+ "texts": [
+ " Moreover, Pai and Palazotto [3] showed that the rigidly translated and rotated frame x1x2x3 can be located by requiring that @u @xn im @u @xm in 18 Substituting Equation (18) into Equation (17) yields dP V 0 JmndBmn dV 0 19 where Jmn 1 2 J\u0302mn J\u0302nm , J\u0302mn f m dxp dxq in, m 6 p 6 q 20 Bmn 1 2 @u @xm in @u @xn im @u @xn im @u @xm in Bnm 21 Here Jmn are the so-called Jaumann stresses and Bmn are the so-called Jaumann strains. We note that Equation (18) makes Jaumann strain and stress tensors symmetric. Cauchy stresses tmn and in\u00aenitesimal strains lmn Since Cauchy stresses are de\u00aened with respect to the deformed area, we need to consider an in\u00aenitesimal element whose deformed shape is cubic, as shown in Fig. 2. Here, the frame x1x2x3 is an orthogonal rectilinear inertial frame, the base vectors along the axes x1, x2 and x3 are j1, j2 and j3, re- spectively. The frame y1y2y3 represents the rigidly translated con\u00aeguration of the frame x1x2x3 and hence the base vectors along the axes y1, y2 and y3 are also j1, j2 and j3, respectively. Moreover, v denotes the absolute displacement vector of the point O and f\u00c4k are forces acting on the deformed surfaces. Using the fact that the elastic energy P of a structural system is due to relative displacements among material particles, one can obtain its variation dP as dP V ~f 1 jn d @v @y1 dy1 jn ~f 2 jn d @v @y2 dy2 jn ~f 3 jn d @v @y3 dy3 jn 22 where V denotes the deformed system volume",
+ " The Cauchy stresses tmn are de\u00aened as tmn ~f m dyp dyq jn ~f n dyr dys jm tnm, m 6 p 6 q, n 6 r 6 s 23 where the fact that tmn=tnm can be proved by using the moment equilibrium equations of the deformed element [2, 5]. The in\u00aenitesimal strains lmn are de\u00aened as lmn 1 2 @v @ym jn @v @yn jm 24 We note that both tmn and lmn are symmetric. Substituting Equations (23) and (24) into Equation (22) yields dP V tmndlmn dV 25 where dV= dy1 dy2 dy3. Equation (25) can be written as [2, 5] dP V 0 t\u0302mndlmn dV 0, t\u0302mn Ftmn 26 where F0 v[F]v = dV/dV0, [F] denotes the deformation gradient tensor, and t\u0302mn are the so-called Kirchho stresses. Almansi stresses Omn and Almansi strains Amn It can be seen from Fig. 2 that @ro @ym jm, @rO @ym 1 lm j ~m 27 where lm denotes the stretch of dym and jm\u00c4 denotes the unit vector along the undeformed direction of dym. Because ro=rO+v, we obtain that d @v @ym jn d @ro @ym jn \u00ff @rO @ym jn d dmn \u00ff 1 lm j ~m jn \u00ff d 1 lm j ~m jn 28 The surface traction force f\u00c4m can be represented in terms of Almansi stresses Omk and stretches lk as [2] ~f m Om1 1 l1 j ~1 Om2 1 l2 j ~2 Om3 1 l3 j ~3 dyp dyq, p 6 q 6 m 29 Substituting Equations (28) and (29) into Equation (22) yields dP V O11 1 l1 j ~1 O12 1 l2 j ~2 O13 1 l3 j ~3 jnd \u00ff 1 l1 j ~1 jn O21 1 l1 j ~1 O22 1 l2 j ~2 O23 1 l3 j ~3 jnd \u00ff 1 l2 j ~2 jn O31 1 l1 j ~1 O32 1 l2 j ~2 O33 1 l3 j ~3 jnd \u00ff 1 l3 j ~3 jn dy1 dy2 dy3 30 Almansi strains (or Eulerian strains) Amn are de\u00aened by using the change of the squared length of an in\u00aenitesimal line segment as 2Amn dym dyn dro dro \u00ff drO drO @ro @ym @ro @yn \u00ff @ rO @ym @ rO @yn dym dyn 31 Hence, Amn 1 2 @ ro @ym @ ro @yn \u00ff @rO @ym @rO @yn 1 2 jm jn \u00ff 1 lm j ~m 1 ln j ~n 1 2 dmn \u00ff 1 lm j ~m 1 ln j ~n 32 where repeated subindices do not imply summation",
+ " 3 that dy1 dx 1 cos y 35a and the displacement component v1 of the points o, a, and g are vo1 0, va1 dx 1 cos y\u00ff 1 , vg1 \u00ffdx 1 sin 2y 35b Using Equations (35a)\u00b1(b) and the de\u00aenitions of strains shown in Equations (4), (9) and (24), we obtain e\u030211 e11 @v1 @x 1 va1 \u00ff vo1 dx 1 cos y\u00ff 1 6 0 36a l11 @v1 @y1 va1 \u00ff vg1 dy1 1\u00ff cos y 6 0 36b Hence, displacement gradients e\u00c3ij, engineering strains eij and in\u00aenitesimal strains lij are non-objective measures. From Equation (32) one can see that, if there are only rigid-body motions, lk=1, jm\u00c4 jn\u00c4=dmn and Amn=0. Hence, Almansi strains are objective. However, rigid-body rotations may make the physical meaning of Almansi stresses very di erent from common de\u00aenitions of stresses. For example, if j1\u00c4 =j2 in Fig. 2, then it follows from Equation (29) that the Almansi stress O11 represents a shear stress (not a normal stress) on the deformed surface dy2dy3 along j2. It also indicates that, in the Almansi stress\u00b1strain equations, the material constants need to be functions of deformations even if it is a small-strain but large-rotation problem. The use of \u00aerst Piola\u00b1Kirchho and engineering stresses also su ers from the same problem. From Equation (14) one can see that, if there are only rigid-body motions, lk=1, ik\u00c3=ik and im\u00c3 in\u00c3=dmn",
+ " However, for curvilinear coordinate systems, @jk/@xm and @ik/@xm may be nontrivial and results in initial curvature-induced terms. Equations (4), (9) and (24) show that the directions of the displacement gradients, engineering strains and in\u00aenitesimal strains are along the undeformed coordinates, which causes the non-objectivity. Equation (14) and Fig. 1 show that the directions of Green\u00b1Lagrange strains are along the directions of im\u00c3 , which are not three perpendicular directions. Equation (32) and Fig. 2 show that Almansi strains are along the directions of jm\u00c4 , which are not three perpendicular directions. Equation (21) shows that the directions of Jaumann strains are de\u00aened with respect to the deformed coordinates and along three perpendicular directions. Such characteristics are convenient for the imposition of shear stress conditions on the bonding surface in deriving the shear warping functions of beams, plates and shells [23]. Equation (21) (Equation (20)) and Equation (9) (Equation (8)) show that Jaumann strains (Jaumann stresses) and engineering strains (engineering stresses) have the same vector form except that jm and v are replaced with im and u"
+ ],
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+ "original_path": "designv11-6/openalex_figure/designv11_6_0000844_1097-4636(200104)55:1<54::aid-jbm80>3.0.co;2-y-Figure1-1.png",
+ "caption": "Figure 1. Schematic representation of the compression of SPHs. Radial (A) and axial (B) compression are shown. The compression of SPHs in the direction of the dotted arrows resulted in compressed SPHs in the shapes on the right.",
+ "texts": [
+ " For some experiments, the weight of the SPH was taken before and after placement in the humidity chamber to determine water uptake in the humidity chambers. Percent weight increase (I) was calculated from the dry weight, wd, and the plasticized weight, wp, according to Equation (1). I = [(wp \u2212 wd)/wd] 100% (1) The SPHs to be compressed were placed in a carver press and compressed with either a \u00bc-inch tablet punch and die or two stainless-steel plates. The tablet punch and die resulted in an axial compression, whereas two steel plates resulted in a radial compression. Figure 1 is a schematic representation of the compression process used. Two plates were used for the radial compression; a tablet punch and die were used for the axial compression. A laboratory Carver Press (Fred S. Carver Co., Menomonee, WI) was used for all of the compression experiments. The hand press was calibrated for pressures from 0 to 1000 lb. After removal from the press, the samples were immersed in absolute ethanol overnight. Samples were then dried in the food dehydrator and stored in a dessicator until use"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003766_biorob.2006.1639165-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003766_biorob.2006.1639165-Figure2-1.png",
+ "caption": "Fig. 2. Optical force sensor attached to the haptic interface. The left image shows the opened sensor with the fiber setup in the middle",
+ "texts": [
+ " Since optical sensors are completely magnetically inert, they have been widely used in the MR environment for the detection of displacement [5] [14] [23], force [24] [25] [26] and torque [24]. Optical fibers are able to transmit signals by a long distance without degeneration, so the circuitry part of the sensor could be put far away from the coil center to avoid interaction with the magnetic field. In particular, the optical force sensor of J. Fu\u0308glistaller is comprised by three optical fibers connected to a processing unit [25]. Two fibers measure the light intensities I1 and I2 emitted by one opposing fiber, see Fig. 2. Force applied to the sensor causes a small dislocation that changes the amount of light received by the two opposing fibers. To make the system less sensitive to diffused light and absorption within the fibers the force is determined by relative rather than absolute intensity changes. A possible problem is the varying transmission losses when the fibers are moved or bended during robot motion. Hence, bending or motion of the optical fiber should be limited. Other approaches of MR-compatible sensors are also possible"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001158_s0925-4005(00)00322-1-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001158_s0925-4005(00)00322-1-Figure1-1.png",
+ "caption": "Fig. 1. Illustration of the enzyme electrode.",
+ "texts": [
+ " It re-activates the enzyme by extracting phosphate pesticides. \u017dAChE EC 3.1.1.7, 1000 Urmg, from Electric eel, type . \u017dV\u2013S and COx EC 3.1.1.17, 10 Urmg, from Arthrobac.ter globiformis were purchased from Sigma. Glutaralde\u017d . \u017dhyde 70% solution, for biochemistry , albumin 10%, . \u017dfrom bovine serum , acetylcholine chloride analytical . \u017d .grade , DDVP standard 99% purity were obtained from \u017d .Wako. PAM 99% purity was purchased from Aldrich. The enzyme electrode was fabricated by the following procedures, illustrated in Fig. 1. About 14 U of AChE and 58.5 U of COx were dissolved in 100 ml of 0.05 M phosphate buffer solution. Five microliters of the enzyme solution was coated directly onto a 5-mmf Pt plate and dried. Then, 50 ml of the above solution was mixed with 10 ml of 10 wt.% albumin and 2 ml of 70 wt.% glutaraldehyde. Five microliters of this solution was coated onto the enzyme-coated Pt plate and dried to form a crosslinked enzyme layer. The enzymes in the inner layer possess each original activities. Further, it is expected that they maintain high activities even in the outer layer, since albumin is believed to immobilize enzymes with little deterioration"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003735_tpwrd.1986.4307990-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003735_tpwrd.1986.4307990-Figure6-1.png",
+ "caption": "Figure 6. Illustration of Hysteresis Effect.",
+ "texts": [
+ " The downside function is simply the upside The probability density function, f(x), can be selected such that h(x) matches any given hysteresis curve. The only constraints are: F(x) must approach or equJal 1 for large x. This means that the integral of f(x) for MMF ranging from 0 to infinity must be 1. h(x) must be asymptotic to the curve x-1. This means that the centroid or mean of f(x) must be at x=l. With these constraints, and by choosing an appropriate starting point, h(x) forms the right-, upward-moving side of the hysteresis curve. Imagine, as shown in Figure 6, that MMF had started at some large negative value, Xl, and steadily increased to X2 along path (a), taking out all the deadband so that the output, Y2, equals X2 minuis 0.5. At this point, let MMF reverse direction. function flipped over and path (b) will be traversed. Let MMF continue down to X3, and again reverse. Now only the smaller elements have traversed their entire deadband. The larger elements have traversed only part way through just as in the example on Figure 4. All those small elements that had completely unwound their deadband will have to go back through in the other direction as MMF steadily increases",
+ " Consequently, the incremental slope following a current reversal varies with the coordinate position. The model of this paper would predict a slope independent of position (within the unsaturated region) which has been noted elsewhere experimentally [21 and theoretically [31. The existing EMTP model also does not provide for the sudden change in slope when overtaking a previous reversal point. Other limitations have been mentioned by users [4]. Could the authors make further comments comparing the existing and proposed models? On the above topic, following Fig. 6, it is noted that a sudden change in slope could induce a (step) change in winding voltage. This may be true only when the remainder of the simulation network has a Thevenin impedance large compared to the magnetizing inductance, with current rather than voltage being maintained constant. This condition could be approximated in certain ferroresonance-type problems. The idea of representing hysteresis as the composition of deadbands is not new, being described in [21, [5], and probably earlier. However, the postulated connection between probability density functions and hysteresis is new to this discusser and would appear to deserve further development since h(x) needs to be supplied by the model user"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003495_004-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003495_004-Figure5-1.png",
+ "caption": "Figure 5. Experiments with a piece of a rubber band.",
+ "texts": [
+ " It can be, since while calculating the circulation of B, we in fact integrate its tangent component B \u00b7 dr2, and the latter remains finite in spite of the divergence of B. As mentioned in the introduction, Darwin grasped, on an intuitive level, the existence of the topological conservation law. To arrive at it, he performed a series of simple experiments. Let us repeat one of the experiments made by Darwin. Take by one end a straight piece of a rubber ribbon and wind it around a pencil observing at the same time the behaviour of the free end: it rotates. But, when the orientation of the other end of the ribbon is fixed, a twist will appear. See figure 5(a). The rigorous explanation of the experiment is as follows. Splice the ends of the initially flat rubber ribbon so that a loop without any twist is formed. The linking number of the borders of the ribbon loop is equal obviously to zero, and it will remain zero whatever we do to the loop. Now stretch a part of the loop and freeze the rest of it. (Making experiments with the stretched part is equivalent to making experiments with a flat piece of ribbon, whose ends are fixed.) In view of the equation Lk = Wr + T w, the sum of the writhe and twist will remain zero. To be rigorous, we should consider the conservation law in its full form: Lk(K,U) = Wr(K)+T w(K,U). This needs a precise indication of what K and K + \u03b5U are. The best choice is to consider one of the ribbon\u2019s borders as the K + \u03b5U and the middle line between the borders, as K. Examining figure 5(a) we can see that the latter remains straight in the twisted part of the ribbon. This makes our reasoning simpler and cleaner. When, as shown in figure 5(a), we wind a half of it into a helix, which introduces writhe into K, the other half must become twisted in the opposite direction and the number of twists will be equal to the number of the helix turns. How do we avoid it? It is obvious: we must wind the ribbon in such a manner that the writhe of K will remain equal to zero. This is achieved when the helical winding starts from both ends with opposite handedness. See figure 5(b). The total writhe Wr(K) will be equal to zero and so will be the twist T w(K,K + \u03b5U). The same happens to a tendril. We treat it as a piece of ribbon. After it has caught a support, both its ends become fixed. Thus, in our imagination we may treat it as a part of a loop, the rest of which is frozen. How it will behave is described above. Obviously Darwin\u2019s considerations could not be so rigorous, but he grasped the idea perfectly well. Here is his reasoning: We can now understand the meaning of the spires being invariably turned in opposite directions, in tendrils which from having caught some object are fixed at both ends"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001376_s0967-0661(99)00084-2-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001376_s0967-0661(99)00084-2-Figure6-1.png",
+ "caption": "Fig. 6. The envelope of the moment gyrocomplex angular momentum.",
+ "texts": [],
+ "surrounding_texts": [
+ "Conventionally, spacecraft attitude control system have been designed in the form of a multifunctional system of combined control, which includes two interconnected multidimensional loops, a closed loop as a basic programmed feedback control and an openloop as an additional disturbance-compensation control (Anshakov, Antonov, Butyrin, Makarov, Matrosov & Somov, 1995; Kozlov, Anshakov, Antonov, Makarov & Somov, 1998). Since it is necessary for the closed loop to operate in the `reference memorya mode for long periods, this is the decisive criterion of e$ciency. The principal meter for this loop has been represented by a Strapdown Inertial Navigation System (SINS). Various meters for spacecraft body attitude and angular rate measurements have been applied to this loop: \"ne gyrosensors (#oat, laser, \"bre-optic, dynamically adjusted, etc.), and opto-electronic sensors (an Earth orientation device in the form of an infra-red horizon sensor, a \"ne Sun sensor, and also \"ne \"xed-head star sensor with a wide \"eld of view), which are intended for the correction of the strapdown system. To provide for the desired quality of image, rather strong requirements are applied to the attitude control of the spacecraft. This has stimulated the search for new techniques for guiding optical telescopes onto observed targets, including direct techniques. The latter employ image motion sensors and precision image motion stabilization systems that are directly embedded in the optical telescope, see Figs. 2 and 3. As far as ultra-precision image motion stabilization system is concerned, the image, which is obtained with the main mirror (1) of the telescope in the light detector (4) has been precisely stabilized using two cascaded closed loops, comprising the o!-set \"ne image motion sensor (5) and micro-processors (6), (9) and (10). The movements of the optical compensators (the secondary mirror (11) and near-focal diagonal mirror (2) is implemented by digital electromechanical (12) and \"ne piezo-ceramic (7) microdrives, see Fig. 4. The group has wide experience in the application of strapdown inertial navigation systems based on a precision inertial gyroscopic assembly using precision #oat gyros, which are rate gyrosensors. In the latest designs, when long-term operation of an attitude control system in the `memorya mode is needed, a strapdown inertial navigation systems based on a 4-channel Russian inertial gyroscopic assembly with two spherical electrostatic gyroscopes is applied. Drift values derived in practice for this type of strapdown system are measured in units of arcsec/24 h. This allows the \"ne \"xed-head star sensor to be substantially simpli\"ed by reducing the necessary sensitivity down to bright stars, and by performing the astronomic correction procedure of the SINS only once in a few days. The group also has wide experience in the application of moment gyrocomplexes based on di!erent types of electromechanical executive devices (reaction wheels with ball-bearing suspension and electromagnetic suspension, as well as momentum wheels and control moment gyros with di!erent degrees of freedom (DOF) and with di!erent types of controlled gimbal suspensions) with moment gearless drives and gear stepping drives (Aref 'yev, Sorikin, Bashkeyev & Kondrat'yev, 1995). The moment gyrocomplexes based on gyrodines are the most e$cient executive devices for fast and frequent changes of a spacecraft's body orientation, achieving precise angular motion stabilization, and they are applied in the attitude control system on the remotesensing Russian spacecraft. The singularity problems (Tokar, 1978; Margulies & Aubrun, 1978) for di!erent moment gyrocomplex' schemes based on gyrodines are carefully investigated in this paper. The moment gyrocomplex with four gyrodines in the `2-SPEEDa-type minimum-excessive fault-tolerant scheme, see Figs. 5 and 6 (Crenshaw, 1973), stands out because of its many advantages when the modi\"ed exact distribution law (Somov, 1997b) of the normed angular momentum between the pairs of gyrodines is used. The large power consumption of the moment gyrocomplex is provided by large-scale solar array panels. Motion-control systems on the remote-sensing Russian spacecraft also have executive devices such as gas reaction thrusters for attitude control, a main reaction thruster in a 2-DOF suspension with the gear stepping drives for orbit control, the gear stepping drives for the angular guidance of solar array panels, as well as highly directive receiving}transmitting antennas, onboard thermal control system radiators, etc. The problem of unloading the moment gyrocomplex from the accumulated angular momentum is quite speci\"c for a low-orbital spacecraft since the aerodynamic disturbing torque is substantially larger than disturbances arising from the Earth's gravitational and magnetic \"elds. The open-loop control with respect to disturbances is intended for both regular compensation of the external disturbing torques, and for unloading the moment gyrocompelx."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003057_0141-0229(86)90134-1-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003057_0141-0229(86)90134-1-Figure2-1.png",
+ "caption": "Figure 2 Plot of the amount of glucose consumed versus the amount of ATP added",
+ "texts": [
+ " 3 nmol rain -~ ; 350 Enzyme Microb. Technol., 1986, vol. 8, June Enzyme electrode for A TP and creatine kinase: G. Davis et al. consequently on the time-scale of the experiment the enzyme electrode does not cause a significant change in the bulk glucose concentration.) Five aliquots (2 pmol) of ATP were then added and the decrease in the steady-state current measured after each addition. From the decrease in current at the precalibrated electrode the amount of glucose consumed was calculated. A plot, Figure 2, of ATP added versus glucose consumed showed that the reaction followed the expected 1:1 stoichiometry, equation (2), and indicated that the complete reaction sequence for assaying creatine kinase, comprising equations (1), (2), (6) and (7) could be tested. The steady-state current response of the glucose enzyme electrode in 1 ml buffer containing glucose (20raM), hexokinase (20 U), ADP (5 mM) and creatine phosphate (20 raM) was initially stable (Figure 3). The glucose concentration used is within the linear range of the enzyme electrode, 6 other reagent concentrations were chosen to ensure that a sufficient excess was present"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002648_bf02439374-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002648_bf02439374-Figure1-1.png",
+ "caption": "Fig. 1 Hencky problem Fig. 2 Circular membrane under",
+ "texts": [],
+ "surrounding_texts": [
+ "the concentrated force and its boundary conditions and Hencky transformation, the problem~ of nonlinear boundary condition were solved. The Hencky transformation wc~ extended and a exact solution of large deformation of circular membrane under the concentrated force has been obtained.\nKey words: circular membrane ; concentrated force ; large deformation; exact solution\nChinese Library Classification: 0344.3 Document code: A 2000 MR Subject Classification: 74B20; 74K35\n1 A x i s y m m e t r y L a r g e D e f o r m a t i o n o f C i r c u l a r M e m b r a n e\nThe problem of axisymmetry large deformation of circular membrane is one with practical\nsignificance. Hencky (1915) ~11 gave a solution of power series under the uniform force; Alekseev (1951) [~-] gave an analytic solution of circular membrane under the concentrated force, which is exact only when v = 1/3. Chien Wei-zang et al . (1981)[3] gave an analytic solution of the symmetrical circular membrane under the action of uniformly distributed loads in its central portion. As for the results or other authors [4-6] were approximate ones.\nthe concentrated force\nIn this paper, the Hencky transformation was extended and a exact solution of large\ndeformation of circular membrane under the concentrated force has been obtained and the solution is simple. The result given in this paper is useful, although the case for this solution is exceptive\n* Received date: 2001-08-28; Revised date: 2002-09-18\nBiography: CHEN Shan-lin ( 1 9 4 2 - ) , Professor\n28",
+ "one of Refs. [2] and [31 ; It is due to that the result is difficult to derive directly from the Refs. [21 and [31 .\n2 B a s i c E q u a t i o n a n d H e n c k y T r a n s f o r m a t i o n ' s E x t e n d i n g\nL e t ' s introduce the following dimensionless parameters:\nr'- E3(1- ~-)]lJ'-,o x - R 2 , Y = h '\nd y 7) --\ndx '\n- 6(1 - ,'-)R'-N~ S =\nEh:~\n[ 3 ( 1 - v2) ] 3 / 2 R 2 p 19 =\n27rEh 4\nwhere r---radial radius; R--circular membrane' s radius; h-- thickness; u---deflection; Nr--radial membrane force; E - - Y o u n g ' s modulus; v - -Po i s son ' s ratio; P--concentrated force.\nThen the basic equation of large deformation of\ncircular membrane under the concentrated force is [37 p = x s v , ( 1 ) Fig. 3 Circular membrane under the action\n( xs )\" = v ~- . of uniformly distributed loads in\nIn which ( ) ' = d / d x . Deleting v and letting z = x s , its central portion\nwe can obtain z\" = p 2 z - : . (2)\nAnd the boundary condition is\nx -- 1, 2z ' - (1 + v ) z = 0. (3)\nThe condition for that is x = 0 at the center of the circular membrance thanks to the concentrated force which induces N r with singularity\nl i m z ( x ) = 0 ( x ~ ) , even a < 1. (4) x~-I)\nThe problems of nonlinear boundary condition, ( 2 ) and ( 3 ) were solved under the condition ( 4 ) .\nIt is supposed that z~ ( x ) is another special solution of Eq. ( 2 ) , then we have a transform\nZ ( X ) ---- a k Z l ( \u2022 l ) , ~C 1 = t'/,~C q- b . ( 5 )\nSubstituting Eq. (5) into Eq. ( 2 ) , we have\na 4 + 3 k d2zl ~2192 (6)\nd x i zT\nSuppose a _= 1 and Eq. ( 6 ) is right forever. So it gives general solution of Eq. ( 2 ) from transform ( 5 ) , b is integral constant. It regards transform (5) as extending of Henky transform under the concentrated forces, because transform (5) is a Hencky transform when b = 0."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003286_0167-2789(86)90076-x-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003286_0167-2789(86)90076-x-Figure1-1.png",
+ "caption": "Fig. 1. The horseshoe, its suspension and its template, a) The suspension of F, b) the template (,,~e\" H, ~t).",
+ "texts": [
+ " Holmes / Knotted periodic orbits in suspensions of Smale's horseshoe 9 t-\", + oo. Applied to the orbits in 12, - collapses the flow along the strong stable manifolds, thus producing a semiflow g~ t on a branched two-manifold .Xe'c M 3. The knot-holder or template (J{, ~,) has the property that any (finite) set of periodic orbits of % corresponds via isotopy to that of ~t: the knots and links induced on X\" by ~, are isotopic to those of the original flow ~t on M 3. We illustrate the process for the horseshoe in fig. 1; the resulting template, (X'n, ~t) is the object of our study here. For more details on its derivation and relevance to nonlinear oscillations, see Holmes and Williams [2]. One can regard this 'reduction-by-one-dimension' procedure as providing a method complementary to the usual one of taking a two-dimensional cross section D c M 3 and defining an diffeomorphism F: D --, D; the Poincarb map (Guckenheimer and Holmes [18], chap. 1). In this connection, the equivalence relation can be viewed as follows",
+ " Since embeddings of the horseshoe are prevalent in nonlinear oscillators and other three-dimensional dynamical systems (Guckenheimer and Holmes [18]), the general situation is evidently more complicated than Beiersdorfer et al.'s conjecture suggests. In this respect our work shows that, once a suspension has been chosen, the sequence of type numbers bj, along with the yj and crossing numbers cj, are completely determined by the word of the base orbit .Thus the 'chaotic renormalization orbits' conjectured by Crawford and Omohundro [17] are not realized in any specific flow. However, clearly by modifying the suspension of fig. 1, introducing additional twists, etc., one can produce infinitely many different sequences for any given base word. See section 6. 5. P e r i o d m u l t i p l y i n g We start by reviewing the generic behavior of area-preserving diffeomorphisms in the neighborhood of an elliptic fixed point. This introduces the notion of period-multiplying sequences and provides a generalization of the doubling sequences of section 4. We also recall the construction of resonant torus knots of Holmes and Williams [2]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.6-1.png",
+ "caption": "Figure 2.6. Finite displacement of a rigid body.",
+ "texts": [
+ " For example, the three coordinates of any par ticle, or any base point, and any three independent angles that specify the orientation of the body frame relative to the spatial frame f/J may be selected. This natural choice is basic to the following description of the most general displacement of a rigid body. The mathematical description of the decomposition of the general dis placement of a rigid body into its translational and rotational parts will be outlined here. Let us imagine that the body shown in Fig. 2.6 undergoes an arbitrary motion in space that carries it from a given initial configuration into another configuration relative to an assigned spatial frame f/J = { F; Ik }. Con sider an imbedded frame q/ = { 0; i~} which is parallel to f/J when the body is in its initial configuration. The corresponding position vectors of a particle P Kinematics of Rigid Body Motion 93 are denoted by x in q/ and X in l/J. After the displacement of the body, P has a new spatial position X in l/J but it retains the same position with respect to the imbedded, body frame. The point 0 initially at B in frame l/J is displaced to 0' at B, as diagrammed in Fig. 2.6. Finally, let us consider in the terminal configuration another auxiliary frame cp = { 0'; ik} which is parallel to l/J, hence also to the imbedded frame cp' in the initial configuration. If x denotes the position vector of P from 0', relative to cp, then the displacement vector of the particle P is given by d(P) =X- X= b +X- X, (2.12) where b = d( 0) = B- B is the displacement of the base point 0. The foregoing description illustrates our discussion of reference frames in the previous section. Indeed, the angles between the ik and ilc vectors in the final configuration may be used to characterize the orientation of the body in its final state in l/J",
+ " A relation that describes an arbitrary rigid body rotation about a fixed base point in terms of the nine direction cosines relating the orientation of the body reference frame in its initial and its final configurations will be derived next. The connection of the result with a rotation about a fixed line will be studied in the following section. To start with, we recall that x is the displaced position vector of P in the spatial frame cp = { 0; ik}, and x is the position vector of P in the body frame cp' = { 0; i~ }, which was coincident with cp initially, as described in Fig. 2.6. Thus, when viewed in cp alone, we envision the same particle P identified by two vectors x = xkik and x = .Xkik separated by an angle 1/J, as shown in Fig. 3.4. This is the usual representation considered in (3.116) and in all of our earlier equations for the displacement vector in an assigned spatial frame cp. Hence, as usual, (3.116) may be written in the following familiar component form in cp: (3.117) However, the same situation may be viewed differently. In the body frame cp' in Fig. 2.6, the point P has always the same position vector p, say. Therefore, it appears always to an observer in cp' that P has the coordinate components {p/J={xd=(x1 ,x2,x3 ) so that p=pkik=xkik referred to frame cp'. Of course, these also are the initial coordinates of P in the spatial frame q>, because the frames coincides initially. But the same vector p after the Final Position of Pin'/! (Xt, X:2, X3) Spatial Frame I{J (x 1 ,x2,x3) Initial Position of P in Frame '{) Figure 3.4. Displacement of a particle P viewed in the spatial frame
t n H (9) where a(t) is the angle between point P and the wavefront of the kith harmonic. Differentiating each side of eqn. 9, we obtain: CO + Vx+ Vz = Txk Tzl (10) where vx, vz are the rotary and linear rotor speeds, respectively, and dt is the angular speed of point P in relation to the kith field harmonic. Similarly, as in the theory of conventional induction motors, we can write Thus, from eqns. 10 and 11, we obtain eqn. 7. This equation can be also derived, using trigonometric transformations, in the following way: The rotor speed v can be divided in two components (Fig. 5) vn and vt. The vt component, which is parallel to the 188 wavefront, does not make any contribution to electromagnetic induction. Thus, the rotor slip in relation to kith field harmonic can be defined as follows: Ski = 1 - (12) where vn and vnM are the rotor and field velocities in the normal direction of the kith wavefront. Looking at the geometric relations of vn (Fig. 5), we have vn = z;cos|3 Since j3 = 7 \u2014 a, eqn. 13 takes the form vn = v cos 7 cos a + v sin 7 sin a Since vz = v cos a and vx = v sin a Hence vn - Vz cos 7 + vx sin 7 From Fig. 5, we have also Vnkl = Vzl COS 7 Inserting eqns. 15 and 16 into eqn. 12, we obtain vz + vx tan 7 (13) (14) Ski = 1 ~ (15) (16) (17) vzl Since tgy = vzl/vxk, eqn. 17 finally takes the form of eqn. 7. Eqn. 7 can also be obtained by starting with the following definition of the rotary-linear slip: s = 1 (18) where vki is the synchronous speed in the direction of the rotor motion (Fig. 5). Eqn. 7 indicates that the slip depends on two components of the rotor speed. If one of them is zero, then the slip takes the form well known in the theory of conventional motors. Considering the direction of the travelling rotating wave speed (Fig. 3), it is noticed that a change of the TX1 or TZ1 value causes a change of the direction of its movement. If we put Txi ->\u00b0\u00b0 in eqn. 6, we obtain a travelling wave, and if TZI ~*\"\u00b0\u00b0. w e n a v e a rotating wave. That means that the description of a helical movement is more general than that of a travelling or a rotating wave"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003735_tpwrd.1986.4307990-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003735_tpwrd.1986.4307990-Figure2-1.png",
+ "caption": "Figure 2. Composite Hysteresis-Saturation Curve. Multiple values of flux can be caused by a single value of MMF.",
+ "texts": [
+ " general, the model can accept any number of windings around the core. 0885-8977/86/0007-0174$01.00\u00a91986 IEEE 175 Each winding is modeled with resistance and self-leakage flux. For generality, mutual coupling outside the steel core is assumed between each pair of windings although only that component of flux linking the primary and secondary windings is shown. The steel core is characterized by a non-linear, history dependent hysteresis-saturation relationship between net MMF and the resulting flux as on Figure 2. Eddy-current effects are modeled by a short--circuited turn. Additional short--circuited turns having different values of resistance and leakage inductance can be included to represent eddy current effects more accurately. is very important, and one that distinguishes the model described in this paper. Completing the core model is a small component to represent the permeance of free-space. Functionally, it is in parallel with hysteresis and saturation. When 4v and 4s are combined to form 4m, it forms a flux that links all coils",
+ " / Core Model Modeling of a laminated steel transformer core involves an input--output relationship between net MMF driving the core and the resulting flux. There are four eVrfctcs that must be modeled; hysteresis, saturation, free-space flux and eddy-currents. From a modeling standpoint, they are each quite different. Eddy currents are induced in core laminations by transformer action and can be modeled simply as another winding or windings (14], similar to that done successfully to model eddy current effects in rotating machines [17). Hysteresis appears to be a multi-valued function of MMF. Given an MMF, Ml on Figure 2, several values of flux seem to be possible. However, given a history of where, (not when), MMF has been, flux is determinable. Saturation, on the other hand, is independent of history. The two effects are postulated to combine in series as illustrated on Figure 3; the input to the saturation function being the output of the hysteresis function. The relationship between these two effects effect forms 4,v. This model is referred to as Fl(MMF). b. Multiple deadband. A more complex mechanism might contain two parallel paths linking input and output, each path, A and B, having its' own deadband"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002285_s0020-7683(00)00153-0-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002285_s0020-7683(00)00153-0-Figure6-1.png",
+ "caption": "Fig. 6. Oil pressure distribution in the pad centerline for di erent arrangements \u00b1 Pinj 0:7 MPa.",
+ "texts": [
+ " If one considers the distribution of bore areas on the pad surface in relation to its center (Table 2), one observes that these are the arrangements with higher percentuals of bores near the pad edges, where the hydrodynamic pressures are lower (0:3 < d=Lz < 0:5). Thus, one can replace the rotor to the bearing center by using a di erence of injection pressures of only 0.25 MPa with a 5-5-5 pad, whereas pressures of 0.3, 0.32 and 0.4 MPa are necessary when using the 7-8, 21-2 and 15, 2-3 and 5 arrangements. Results presented in Table 2 were obtained summing the areas of the ori\u00aeces which were positioned in a given distance d to the pad center, and later calculating the percentuals within certain ranges (Fig. 5). Fig. 6 shows a comparison between arrangements 5-5-5, 2-3, 5 and conventional, of the pressure distribution in the pad centerline, in both y and z directions. One can see that one has an increase of pressure in areas where there is not high pressures in the conventional case. This is the cause of a better performance of pad 5-5-5 in centering the rotor, since this arrangement increases the pressure near the edges in both directions. In order to investigate the e ciency of di erent types of pads in cooling the oil \u00afow in he bearing gap, by injecting cooled oil through the bores, a di erence of injection pressures between pads 2 and 4 was used, within the range of 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002381_robot.2001.933052-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002381_robot.2001.933052-Figure1-1.png",
+ "caption": "Figure 1: Flexible manipulator",
+ "texts": [
+ " However, precise state estimation by this method becomes difficult when the virtual link division number is large, which is the case that the links have much more flexibility. In this paper, we propose a state estimation method based on discrete position information of flexible links by visual sensor. Some previous research [6] used visual sensors to control flexible manipulators, but the visual sensors were utilized just to measure the tip position of flexible link, not to estimate the state variables directly. 2 Flexible Manipulator We consider a flexible manipulator shown in Fig.1 in this paper. It is N d.0.f. plane manipulator which has serial N flexible links and N joints, and fixed on the inertial coordinate system Co. Each joint displacement is 8 = [&,&,... , Q N ] ~ . The length of link i ( i = 1 , 2 , . . . , N) without elastic deformation is I , , and the mass is m,. 0-7803-6475-9/01 /$I O.OO@ 2001 IEEE 2840 as natural frequencies, the minimum IC is constrained by the sampling theorem. The link i coordinate system E, is fixed on the center of joint i. Its 5, axis is along link i when it's not deformed, z , axis is along the displacement axis of joint i, and y2 axis is determined to compose the right hand coordinate system"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003554_13552540510601309-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003554_13552540510601309-Figure4-1.png",
+ "caption": "Figure 4 Volume Ve under surface with re-entrant sides",
+ "texts": [
+ " It can only be applied for surfaces bounded by iso-parametric curves. Also, the above integration is not valid for a surface that has more than one z coordinate value for a particular combination of x and y, i.e. a surface that folds over itself in z-space. In some literature, these surfaces are referred to as those with re-entrant sides (Gupta et al., 2004). However, in such cases, equation (3) may be employed that yields the volume engulfed by the surface and the vertical columnar volume beneath it extended up to the z \u00bc 0 plane (Figure 4). V e \u00bc ZZ z\u00f0u; v\u00deJ dudv \u00f03\u00de The Jacobian J corresponds to the vertical component of the normal to the surface given by ! nz \u00bc \u203ax \u203au \u203ay \u203av 2 \u203ax \u203av \u203ay \u203au \u00f04\u00de Thus, for surfaces with re-entrant sides, the Jacobian J would change sign with ! nz and hence application of equation (3) would yield the volume engulfed by the surface. Surface re-construction \u2013 Bezier surface fitting to CAD model surface patch The portion of the CAD model surface associated with the cusp volume is not necessarily an iso-parametric patch (i"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002220_s0045-7949(02)00003-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002220_s0045-7949(02)00003-2-Figure1-1.png",
+ "caption": "Fig. 1. Physical configuration of a partial journal bearing (transverse roughness).",
+ "texts": [
+ " Based upon the Christensen\u2019s stochastic model [12,13], the stochastic Reynolds-type equation is derived to take into account the presence of roughness on the bearing surfaces. The dynamic film pressure and force is solved and applied to derive the nonlinear motion equation of the journal. The dynamic squeeze-film characteristics (including the journal-center velocity, journal-center locus, and maximum eccentricity ratio) are then evaluated. To show the effects of surface roughness on the bearing operating under cyclic loads, the results are compared with the smooth-bearing case and presented for various values of roughness parameter and Sommerfeld number. Fig. 1 shows the pure squeeze-film configuration of a long partial journal bearing. The journal of radius R is approaching the bearing surface with a squeezing velocity ( ohT=ot). It is assumed that thin film lubrication theory is applicable and the flow in bearing is incompressible, isothermal and laminar. The Reynolds-type equation is given by o ox h3T op ox \u00bc 12l ohT ot \u00f01\u00de The local film geometry hT is treated as a stationary, ergodic, stochastic process with zero mean, and is considered to be made up of two parts: hT \u00bc h\u00f0x; t\u00de \u00fe d\u00f0x; z; n\u00de \u00f02\u00de where h\u00f0x; t\u00de represents the nominal smooth part of the film geometry depending upon the coordinates x and the squeezing time t"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.1-1.png",
+ "caption": "Figure 2.1. Displacement of a particle and parallel translation of a rigid body.",
+ "texts": [
+ " Our immediate objective in this chapter will be to derive from the exact finite displacement vector equation special representations for the velocity and acceleration of the particles of a rigid body that separate and exhibit clearly the translational and rotational parts of the body's motion. Afterwards, several sample applications of these results will be presented. We shall con clude our study with discussion of some useful theorems related to instan taneous screw motions. Let us begin with a few definitions of terms needed in our study. Let a rigid body :11 undergo an arbitrary displacement in space relative to an assigned Cartesian frame cfJ = { 0; ek }, as shown in Fig. 2.1; and let X and X denote the respective position vectors of a particle P in its initial and final positions from 0. Then, regardless of the actual motion of P between these positions, the vector d(P) =X- X defines the finite displacement of P in cfJ. Hence, d(P) is named the displacement of P relative to cfJ. A motion of :11 in which every material point sustains the same dis placement d is called a parallel translation, or briefly, a translation. In this case, d(P) = d is the same vector for every particle P in :11. Therefore, any arbitrary motion that the body may have suffered in reaching its terminal state is the same as a motion in which its particles traverse parallel, straight line paths, as shown in Fig. 2.1, though the body need not move on that line at each instant. (See Problem 2.1.) Whenever the initial and final spatial position vectors of at most one point P are the same, then d(P) = 0 only for that one point. The arbitrary motion that the body may have experienced in achieving its end state is indistinguishable from any other having the same end state and for which P is Kinematics of Rigid Body Motion 87 assumed to be fixed in >; hence, the displacement of !11 is described as a rotation about a fixed point"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003926_1.338581-Figure40-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003926_1.338581-Figure40-1.png",
+ "caption": "FIGo 40 A typical shape of the region O.",
+ "texts": [],
+ "surrounding_texts": [
+ "Numerical Methods Dan Bloomberg, Chairperson\nThe Preisach model and hysteretic energy losses I. D. Mayergoyz and G. Friedman Electrical Engineering Department and Institute for Advanced Computer Studies. University of Maryland. College Park, Maryland 20742\nUsing Preisach's model, general expressions for hysteretic energy losses are derived. These expressions are valid for arbitrary (not necessarily periodic) variations of magnetic field. Moreover, these expressions are given in terms of Preisach's function as well as in terms of experimentally measured \"first-order transition curves.\" A formula is also found which relates the hysteretic energy losses for arbitrary field variations to the losses ocurring for certain periodic variations of magnetic field. This formula allows for easy measurement of hysteretic losses occurring for arbitrary field variations.\nINTRODUCTION\nA hysteresis phenomenon is associated with some ener gy dissipation which is often referred to as hysteretic energy losses. The problem of determining hysteretic energy losses is a classical one. The solution to this problem has long been known for the case of periodic (cyclic) variations of magnet ic field. In that case, the hysteretic energy losses are equal to the area enclosed by a hysteresis loop resulting from a peri odic field variation. However, energy dissipation is a contin uous process, and it occurs for arbitrary (not necessarily periodic) variations of magnetic field. The problem of com puting hysteretic energy losses for the above general case has remained unsolved. A solution to this problem would be of both theoretical and practical importance. From the theo retical point of view, the solution of the above problem will allow for the calculation of internal entropy production, I which is a key point in the development of irreversible ther modynamics of hysteretic media. 2 It will also lead to the expression for the energy stored in the magnetic field which eventually may help to find electromagnetic forces in hyster etic media. 3 From the practical viewpoint, the solution of the problem may bring new experimental techniques for the measurement of hysteretic energy losses occurring for arbi trary field variations.\nIt should not be surprising that the solution of the prob lem has been known only for the case of periodic variations of magnetic field. The reason is that for cyclic field variations the expression for energy losses is easily derived using only the energy conservation principle; no knowledge of actual hysteresis mechanisms is required. The situation is much more complicated when an arbitrary variation of magnetic field is considered. Here, the energy conservation principle alone is not sufficient and an adequate model of hysteresis should be employed in order to arrive at the solution of the problem. It turns out that Preisach's hysteresis model is very well suited for this purpose.\nIn this paper, Preisach's model is used to derive general expressions for hysteretic energy losses. These expressions are given in terms ofPreisach's function as well as in terms of experimentally measured \"first-order transition curves.\"\nFurthermore, a formula is found which relates the hysteretic energy losses occurring for an arbitrary field variation to the losses occurring for certain periodic field variations. This formul.a leads to a simple technique for the measurements of hysteretic losses occurring for arbitrary variations of mag netic field.\nIt has been emphasized before4-7 that Preisach's model is purely phenomenological and can be used for the math ematical description of hysteresis of any physical nature. For this reason, the expressions for hysteretic energy losses de rived in this paper are quite general and valid regardless of the physical nature of hysteresis. The only requirement is that such hysteresis can be described by Preisach's model.\nEXPRESSIONS FOR HYSTERETIC ENERGY LOSSES\nTo make the exposition more or less self-contained, the main facts concerning Preisach's model will be briefly re viewed. The detailed information on this subject can be found in Refs. 4--8. For the sake of generality, we shall de scribe Preisach's model in a purely mathematical form. In this form, any hysteresis nonlinearity can be characterized by an input u(t) and an output J(t). In magnetic applica tions u (t) is the magnetic field, while f( t) is the magnetiza tion.\nConsider an infinite set of operators r a{3 which are rep resented by rectangular loops on the input-output plane (Fig. 1). Along with these operators, consider a weight fune-\n3910 J. Appl. Phys. 61 (8),15 April 1987 0021-8979/87/083910-03$02.40 \u00ae 1987 American Institute of Physics 3910 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37",
+ "tiontt (a,p) which is often called Preisach's function. Then, Preisach's model is given by\nf(t) = J J fl (a,/J)r afJ u(t)dad{J. (1)\na>{3\nFor hysteresis nonlinearities with closed major loops the functiontt{a,p) has a finite support within some triangular area T on the a-{3 plane.\nThere is a one-to-one correspondence between opera tors YaP and points (a,/J) on the half-plane a>p. Using this fact, it can be found that, at any instant oHime, the triangle T is subdivided into two sets (Fig. 2): S + (t) and S - (t) con ~isting of points (a,/3) for which Yapu(t) = 1 and YaP u(t) = - 1, respectively. The interface L(t) between S + (I) andS - (t) isa staircase line the vertices of which have a and {3 coordinates coinciding with local maxima and mini ma of u (t) at previous instants of time. The final (attached to the line a = f3) link of L(t) is horizontal and moves up when the input increases, and it is vertical and moves from right to left when the input decreases. For any given hystere sis nonlinearity, Preisach's function tt(a,{3) can be found from the set of \"first-order transition (reversal) curves\" at tached to the limiting ascending branch (Fig. 3). The appro priate formulas are\nF(a,/J) = fa -laP' (2)\n( ,{3) - 1 a2F(a,fJ) fla ---\n2 8a8p (3)\nIt turns out (see Refs. 5 and 8) that the integral in Eq. (1) can be directly expressed in terms of F(a,/J) as follows:\n1 n\nlet) = -2F (ao,/3o) + k~l [F(ak,Pk_d - Fad 3k)]'\n(4)\nwhere {ak} and {Pk} are decreasing and increasing se quences of a and /3 coordinates of interface vertices, respec tively, and n is the number of horizontal links of L (t) .\nIt has been proved in Ref. 6 that two properties consti tute necessary and sufficient conditions for the representa tion of a hysteresis nonlinearity by Preisach's model. These properties are the \"wiping-out property\" and the \"con gruency property.\" For the discussion of those properties see Refs. 6 and 7. In the sequel, we shall assume that these prop erties are satisfied, and Preisach's model is valid.\nNow we are equipped to proceed to the derivation of expressions for hysteretic energy losses. We begin with the case when a hysteresis nonlinearity is represented by a rec-\n3911 Jo AppL Phys., Vol. 61. Noo 6, j 5 April 1967\ntangular loop shown in Fig. 1. If a periodic variation of input is such that the whole loop is traced, then the hysteretic energy loss for one cycle equals the area 2(a - [3), enclosed by the loop. It is dear that the horizontal links of the loop are fully reversible and, for this reason, no energy losses occur when these links are traced. Thus, it can be concluded that only \"switching-up\" and \"switching-down\" result in energy losses. It is apparent (on the physical grounds) that there is symmetry between these two \"switchings\" and, consequent ly, the same energy losses (equal to a - {3) occur for each of these switchings. The product f.i (a,/3) Ya/3 can be construed as a rectangular loop with output values equal to \u00b1 /-L (a,/3). For this reason, switchings up or down of such a loop win result in energy loss p(a,{3)(a - /3). According to Prei sach's model (1), any input variation is associated with swi tchings up or down of some rectangular loop f.i (a ,/3) Yap. Thus, the energy loss occurring for an arbitrary input vari ation is naturally equal to the sum of energy losses resulting from the switchings of rectangular loops during this input variation, Since we are dealing with a continuous ensemble of rectangular loops, the above summation should be re placed by integration. Thus, if n denotes the region of points (a,p) for which the corresponding rectangular loops were switched during some input variation, then the hysteretic energy loss Q for this input variation is given by\nQ = I f j.l(a,f3)(a - {3) da d[3. (5)\nII\nA typical shape of the region n is shown in Fig. 4. It is clear from this figure that n can be always subdivided into a trian gle and some trapezoids, The trapezoids, in turn, can be rep resented as differences of triangles. Thus, if the integral (5) can be evaluated for any triangular region, then this integral can be easily determined for any possible shape of fto It makes sense to compute the values of integral (5) over var-\nI. 00 Mayergoyz and G. Friedman 3911 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37",
+ "ious triangles. Using these values, hysteresis losses can be easily found for any variation ofinput. In the case when n is a triangle, the integral (5) can be easily evaluated in terms of F(a,{:J) , which is related to the \"first~order transition curves\" by formula (2). The derivation proceeds as follows: It can be verified that\n(j2 --[F(a,{:J) (a - {J) ] (ja8p\n= a 2F(a,p) (a _ (3) + aF(a,{:J) oa a/3 ap\n_aF~(:.....-a.:!....J3.:.-) . (6) da\nUsing Eqs. (3) and (6), we find\n2jt(a,/3) (a _ (3) = 8F(a.{3) _ aF(a,/J) 8P oa\n(j2 - -- [F(a.{3)(a - {3) ]. (7)\naa 8{3\nNow, consider a triangle T(u+,u_) swept (see Fig. 5) dur~ ing the input increase from u _ to u +. According to Eq. (5), such input variation is associated with the losses\nQ(IL,U+) = f f p,(a,/3)(a - (3)da d/3 T(,,+,u ,.)\n= i~+ ([ jt(a,{J)(a - /3) d/3 )da\n= iU ,+ (Lu + p(a,/3)(a -fJ)da )d/3. (8)\nSubstituting Eq. (7) into Eq. (8), performing the integra tion and taking into account that F(a,a) = 0, after simple transformations we find 1 rru , lU' Q(u_,u+) = - 2\" Uu_ F(a,u_ )da + \"_ F(u+.{3)d{3\n- (u+ - u_ )F(U+,U_\u00bb) . (9)\nIt can be shown that the derived expressions for hysteretic energy losses are consistent with the classical result: the hys teretic energy losses for any cyclic input variation equal the area enclosed by the loop resulting from the cyclic input\n3912 J. Appl. Phys., Vol. 61, No.8, 15 April 1987\nvariation. The proof is omitted. Consider a cyclic variation of input from u _ to u + and back to u _. During the monotonic increase of input from u_ to u+, the final horizontal link of L(t) sweeps the triangle T( u + ,u ._ ). On the other hand, during the monotonic de crease of input from u + to u _, the final vertical link of L (t) sweeps the same triangle. Thus, it can be concluded that, for any loop, the hysteretic losses occurring along ascending and descending branches are the same:\n(10)\nNext, we shall use expression (10) to find the formula which relates hysteretic energy loss occurring for an arbi trary monotonic input variation to certain cyclic hysteretic losses. Suppose that the input u(t) increases monotonically from some minimum value u_ and reaches successively some values uland U2, (u2>u I). We are concerned with the hysteretic loss Q( u I,U2 ) occurring during the input variation between U I and u2\u2022 For the above input variation, we have: n = T(u2,u_) - T(ul,u_). Consequently,\nQ(ul,UZ) = Q(U_,U2) - Q(u_,u 1). (11)\nUsing Eq. (10), losses Q(u_,u 2 ) and Q(u_,u 1 ) can be ex~ pressed in terms ofcycliclosses Q(u_,u l ) = ~Q(U_,Ul) and Q(U_,U2) = ~Q(U_,U2)' where Q(u_,u j ) and Q(u_,u2) are cyclic losses for periodic input variations between u_ and U 1, u_ and U z, respectively. Using this fact, from Eq. (11) we find\n(12)\nThe last formula can be useful from the experimental point of view because it is much easier to measure cyclic losses than losses occurring for nonperiodic input variations.\nACKNOWLEDGMENTS\nThe reported research was motivated by the question raised by Professor H. A. Haus during the talk given by the first author at MIT. This research is supported by the U.S. Department of Energy, Engineering Research Program (contract no. DE-AS05-84EH13145).\n11. Prigogine, Introduction to Thermodynamics of Irreversible Processes, 2nd edition (Wiley, New York, 1961). 2J. S. Cory and J. L. McNicols, J. Appl. Phys. 58, 3282 (1985). 'P. Penfield, Jr. and H. A. Haus, Electrodynamics of Moving Media (MIT, Cambridge, MA, 1967). 4M. Krasnoselskii and A. Pokrovskii, Systems with Hysteresis (Nauka, Moskow, 1983). 51. D. Mayergoyz, J. Appl. Phys. 57, 3903 (1985). \"T. Doong and I. D. Mayergoyz, IEEE Trans. Magn. MAG-21, 1853 (1985). 71. D. Mayergoyz, Phys. Rev. Lett. 56,1518 (1986). 81. D. Mayergoyz, IEEE Trans. Magn. MAG-22, 603 (1986). 9J. A. Barker, D. E. Schreiber, B. G. Huth, and D. H. Everett, Proc. R. Soc. London Ser. A 386,251 (1983).\nI. D. Mayergoyz and G. Friedman 3912 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP:\n128.138.73.68 On: Tue, 23 Dec 2014 09:06:37"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002082_s1350-4533(01)00125-4-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002082_s1350-4533(01)00125-4-Figure2-1.png",
+ "caption": "Fig. 2. Inertial force and moment of link i and forces and moments applied to link i by its neighboring links, i 1 and i+1.",
+ "texts": [
+ " Applying the Newton\u2013Euler equations: Fi F\u2217 i 0 (1a) where F\u2217 i miv\u0307ci, (1b) And Ni N\u2217 i 0 (2a) where N\u2217 i (ciIiw\u0307i wi \u00d7 ciIw\u0307i), (2b) the inertial force and moment on link i were computed, where Fi and Ni represent the resultant force and moment, respectively, applied to each link, F\u2217 i is the inertial force acting at the center of the mass of link i, mi is the mass of link i, v\u0307ci is the acceleration vector of the center of mass of link i, N\u2217 i is the inertial moment acting at the center of mass of link i, ciIi is the inertial tensor of the link i with center of mass at the origin of the fixed link frame, and wi and w\u0307i are the angular velocity and angular acceleration vectors of link i. Force and moment equations were applied to calculate the external torques and forces associated with the accelerations. Based on a free body diagram of a typical link (Fig. 2), Eqs. (1a,b) and (2a,b) become: Fi fi ( ifi+1) (3) and Ni ni ( ini+1) ( iPc) \u00d7 fi (iPi+1 (4) iPc) \u00d7 ( ifi+1), where fi is the force exerted on link i by link i-1, measured in frame i, ni is the torque exerted on link i by link i-1, measured in frame i, ifi+1 is the force exerted on link i+1 by link i, measured in frame i, ini+1 is the torque exerted on link i+1 by link i, measured in frame i, iPc is the position vector of the center of mass of link i in frame i. Rewriting the Eqs. (3) and (4) in terms of a rotation matrix, R\u2217, the force and torque equations appear as iterative relationships from the higher-numbered neighbor to the lower-numbered neighbor: fi Fi i i+1R i+1fi+1, (5) and ni Ni i i+1R i+1ni+1 iPc \u00d7 Fi (6) iPi+1 \u00d7 i i+1R i+1fi+1, where i+1fi+1 is the force exerted on link i+1 by link i, measured in frame i+1 and i+1ni+1 is the torque exerted on link i+1 by link i, measured in frame i+1"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000704_a:1008228120608-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000704_a:1008228120608-Figure10-1.png",
+ "caption": "Figure 10. Event maps corresponding to different values of Vdr showing the existence of a partition.",
+ "texts": [
+ " That is, there exist periodic points of any prime period (for the second iterate), and uncountably many orbits that are not even asymptotically periodic. Finally in some cases it seems possible to detect a partition of intervals a, b, and c on the interval of definition of the \u2018permanent\u2019 map, as suggested by Figures 10a and 10b, corresponding to the values Vdr = 0:0811 and Vdr = 0:0813. It is reasonable to hypothesise the existence of a map with a superstable period-4 orbit which was approximately found for Vdr = 0:0812 (Figure 10c). Such an orbit divides the interval of definition of the \u2018permanent\u2019 map in three sub-intervals a, b, c which are mapped in the following way: f(a) b; f(b) c; f(c) a [ b [ c: (6) The transition matrix A (or Markov graph) is constructed according to the rule: Aij = 1 if f(ai) aj and zero otherwise: A = 0 B@ 0 1 0 0 0 1 1 1 1 1 CA : (7) The construction of the transition matrix enables us to count the number of period-m orbits. If Nm denotes the number of fixed points of fm then: Nm = tr(Am): (8) Part of these Nm orbits are trivial, i"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002915_s00170-004-2449-0-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002915_s00170-004-2449-0-Figure2-1.png",
+ "caption": "Fig. 2. a Percentage values of failure frequency b Percentage values of downtime",
+ "texts": [
+ " It contained the following information: 9 Product name, model and size 9 Product code 9 Reported time and date of failure 9 Failure phenomena 9 Cause of failure 9 Repair process 9 Repair time 9 Downtime 9 Date of handover 9 Model, size and number of breakdown components 9 Number of service engineers or repair engineers 9 Site of machine tool As indicated earlier, a lathe has been classified broadly into having the subsystems of headstock, tailstock, carriage, feed mechanism, electrical and coolant. In this analysis, failure frequency and downtime have been taken into consideration for deciding critical subsystems in a lathe. Figure 2a and b show the percentage values of frequency of failures and breakdown for different subsystems, respectively. It can be seen from Fig. 2a that the maximum number subsystem, it was observed that the gear and bearing element form the most significant components. This study focused on the condition monitoring studies of spindle bearings (taper roller bearings). of failures took place in electrical and headstock subsystems. The headstock subsystem has observed more downtime than the electrical subsystem, as shown in Fig. 2b. The electrical subsystem has faced failures on fuses, connectors and switches that required less downtime. The headstock subsystem has faced failures in components like the gears, gearbox bearing, spindle bearing, spindle clutch and cross-slide jib. It was observed that the gear and bearing failures cause longer downtime. All failures in the lathe have been grouped into four-failure modes: component damage, burnt fuse, circuit fault and looseness. Figure 3 gives failure modes and their relative failure frequencies"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000470_s0043-1648(97)00232-9-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000470_s0043-1648(97)00232-9-Figure2-1.png",
+ "caption": "Fig. 2. t'-Z(; tesl machine I~1.",
+ "texts": [
+ " all tests were performed using the same oil type but different ADI gears. The wear and sculling resistance of each ADI gear is then established by comparison with results from other similar FZG tests. 3.2. Procedures The FZG A/8 .6 /90 test consists in imposing a sequenUal load to the tested working gear for periods of 15 rain (stages). When stage 12 is attained, contac! pressure at gear teeth surfaces reaches about 2 GPa. Gears are mounted inside a closed box (carter) bathed in the lubricating oil ( see Fig. 2). The oil temperature is raised and stabilized at 90\u00b0C before running each stage of the test. During each of these stages, an electric motor coupled Io the wheel axis imposes a constant angular speed of 1500 rpm. The test ends when teeth contact surfaces are considered as scuffed I when lhe lotal length damaged by adhesion scratches equals a tooth width). The test result is expressed by the number of stages gears managed to work until scuffing o c c u r s . 3.3. Data gathering Besides the number of stages a gear works until scuffing, other parameters are recorded along each lest stage"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003219_iros.1992.594551-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003219_iros.1992.594551-Figure8-1.png",
+ "caption": "Fig. 8. The shaping constraint.",
+ "texts": [],
+ "surrounding_texts": [
+ "the robot may attain. Inadmissable regions (c-space \u201cobstacles\u201d) correspond to impossible configurations such as interpenetration of the robot and objects in the environment. Now, the start and goal configurations can be specified as points in the c-space and the navigation task is reduced to finding a path between these points while avoiding the c-space obstacles. Other researchers have extended these ideas to produce plans that transform the world from a start state to a goal state [ 121. Here a point in the c-space describes a configuration of the world rather than the robot. A path between two points in cspace can be found as before, only the path represents movement of the various parts of the world towards their final destination and thus provides a prescription for a robot.\nThere are two main stumbling blocks in using\u2018c-space methods. The lirst arises from the complexity of c-space obstacles. C-space obstacles are hard to describe analytically even in three dimensions. For low dimensions (fewer than 5), it is tractable to build a volumetric (as opposed to exact) model of the c-space obstacles, before the planning starts. The c-space is divided into voxels that are either occupied or free, and, the solution now proceeds by finding a path from start to goal [131. For higher dimensions, it is hopeless to attempt a volumetric representation because of the very large number of cells in the space. One solution is to skip the step of computing the c-space obstacles before the fact, and, proceed with navigation in the cspace using a good collision-checker [ 141 that keeps the gradient descent from running into obstacles.\nThe second stumbling block is that unless a globally exhaustive method is used, the search follows the local gradient and is not guaranteed to find the best path or to even get to the goal. A serious problem with gradient descent methods is that they are prone to getting stuck in local extremas. In the excavation domain, this would mean that the excavator had created a state from which it could not be able to readily proceed towards the goal without putting some soil back. Fortunately, this is a rare occurrence for most excavation tasks. The more common problem corresponds to moving along one side of a ridge in c-space, along which the rate of travel is slow. The smart thing to do would be to cross the ridge and proceed at a much faster rate, but this is not possible by gradient descent methods.\nThe main problem in using c-space methods for excavation is that the necessary representation would be so large that it would be intractable. This is because the c-space would necessarily have to encode all possible states of the terrain. Since soil is deformable, we would need a very large number of variables to represent the state of the terrain, in contrast to rigid bodies that can be represenred uniquely by a few parameters.\nSome researchers have used an operation space, an augmented c-space that includes essential action variables that uniquely specify task execution [151. For example, in the squeeze grasping domain where the robot is trying to grasp an object, the position and orientation of the object forms the cspace, while the operation space additionally includes separate dimensions for control variables like pushing direction. Construction of such a space allows the identification of actions that are guaranteed to succeed.\nSince it is not tractable to represent the state of the terrain\nexplicitly for the excavation task, we propose to formulate the task in an action space that is spanned only by the variables required to parameterize the task. The state of the terrain is implicit in this space; it is reflected by the imposed constraints. Instead of finding a trajectory in a high dimensional c-space, we will now look for a single point that optimizes a cost criterion in a lower dimensional action space. The cost of this simplification is that the selected point in the action space specifies only one dig and at most we can be sure that we have picked the best dig on a per dig basis but not necessarily the one that will provide the most gain over the entire task. Neither can we be certain that the search will escape local extrema. Hence, although we have avoided the issue of a very large search space with complex obstacles to avoid, the second issue of search remains.\n111. THE APPROACH\nIn order to provide an intuitive understanding of the proposed approach, let us consider an extended example in a twodimensional world. Fig. 3 Fig. 3 shows a terrain that must be excavated and Fig. 4 shows the conventional version of a mechanism that is to be used.\nThis sort of device is commonly called a \u201cbucket loader\u201d or a \u201cfront-end loader\u201d and can be automated. The loader is M completely excavate the pile, without intruding below the surface of the ground. In this example, we will show how geometrk and force constraints are imposed on the acuon space (a, d , h) from Fig. 2. Force constraints are refined through force feedback data obtained during experimentation. The constrained volume is then searched to select a dig that maximizes the amount of soil obtained. Finally, the selected dig is executed using control scheme that ensures robust excavation. A. Geometric Constraints\nLet us consider three types of geometric constraints that can be imposed on the action space: reachability, volume and shuping.",
+ "Reachability Constraint: This constraint separates the action space into digs that are kinematically feasible and those that are not. We will model the excavator as a P-R-R manipulator shown in Fig. 5.\nGiven a candidate dig, that is a trajectory for the bucket tip to follow, a standard inverse kinematics method is used to find the corresponding joint displacements (dl , 02, e3). A candidate dig may fail this constraint if it is required that the excavator reach outside its workspace (exceeds joint limits) or if in the course of the dig, one or more of the links are required to interpenetrate the terrain. The composite constraint surface due to the terrain in Fig. 3 and the excavator in Fig. 4, is shown in Fig. 6. The surface represents the boundary between the reachable and nonreachable digs- all points below the surface represent digs that meet the reachability constraint.\nVolume Constraint: Since the excavator bucket can only hold a volume Vmax, then an (a, d, h) triplet should not excavate more than this amount of soil. This gives us a further basis on which we can limit the set of feasible digs. This constraint is shown in Fig. 7.\nShaping Constraint: This constraint is given by the goal state of the terrain. In general this may be an arbitrary, stable, geometric specification of the earth. For our example, we will limit digs so that they do not intrude below the surface of the\nB. Force Constraints\nIf we assume that the robot excavator is infinitely strongthat it can muster any torque required, then the type of constraints discussed above are sufficient. More realistically, for robots with torque limits, we must consider the forces required to accomplish digging. Pushing on a section of soil results in failure along an internal rupture surface, also known as a failure surface. The force necessary to perform a particular dig is therefore partly dependent on the force necessary to fail the soil along the rupture surface, or, in other words to overcome the shear strength of the soil along that surface.\nCalculation of cutting resistance forces is not simple to estimate, because in general, the failure plane inside the soil is unknown. There is some research on the operation of earthmoving machinery [ 17][18] that explicitly addresses the issue of estimating forces necessary to overcome the shear strength of soil. Unfortunately, this work is mostly stated in empirical terms for specific types of machines. There is little attempt to work from first principles that use measures of well known soil properties. There has also been some work in the field of agricultural engineering that is directed at producing estimates of cutting resistance for tilling implements [19][20] using well understood physical principles. Unfortunately, the motions of the cutting surfaces analyzed for tilling are different enough",
+ "from those common in excavation, that a carryover of these formulations to the excavation domain is not immediately evident.\nThere are, however, some interesting ideas that can be gleaned from the tillage research. For example, McKyes claims that since an excavator bucket has side walls that cause soil to move inside the bucket, a two dimensional analysis can be used to estimate the cutting resistance. This is a useful insight since three dimensional analysis of a blade moving through soil is significantly more complex.\nIn lieu of a readily available model of soil-tool interaction, we will resort to a simple model that relies on well known principles in soil mechanics, so as to obtain order of magnitude estimates of cutting resistance. For our three parameter digs operating in dry uncompacted soil, there are two kinds of interactions between the bucket and the soil. The first is during the insertion phase, when the bucket edge is driven straight along the approach angle, into the soil. The maximum resistance experienced, till the bucket fills up, is at the deepest point of this phase. In the next phase, the bucket is lifted straight up. We might approximate the shear surface as being along the direction that edge of the bucket is going to lift through (Fig. 9).\nIn the second phase, the maximum resistance is encountered just as the blade starts to move up through the soil. At this point the force necessary to move the bucket is the sum of force necessary to overcome the weight of the soil in the bucket and the force necessary to fail the soil along the predicted shear surfacr. All (a, d, h) triplets for which the force required is greater than the maximum force available, will be ruled inadmissable. The force, F, necessary to excavate is given by:\nF = vy+fs (1)\nfs = 7 . A (2)\nwhere v is the volume of soil excavated, y is the density of soil, f, is the shear force necessary to fail the soil.f, is given by\nwhere 2 is the shear strength of the soil and A is the area of the failure plane- a product of the length of the failure plane and the width of the bucket. Since this is a two-dimensional analysis, the bucket will have unit width.\nThe basis of soil mechanical strength is ascribed to Coulomb (1776) who noted that there appeared to be two mechanical processes which determine the ultimate shearing strength of a material. One process (friction), he noted, is proportional to the pressure acting perpendicularly on the shearing surface. The other process (cohesion) seemed to be independent of normal pressure. The shear strength of a soil, T, is therefore modeled as\na sum of these two components:\nT = c+otan@ (3)\nwhere c is the cohesion, cr is the normal pressure acting on the internal shear surface' and tan @ is the coefficient of sliding friction. $ is also called the angle of internal friction and is directly visible as the angle of repose of a pile of dry, uncompacted granular material like sand and sugar.\nSo far, in this section we have said that if the soil properties (density, angle of internal friction, cohesion) are known, it is possible to get order of magnitude estimates of the resistance force encountered for the type of digging motions that have been proposed. The action space can now be further constrained based on whether or not it is possible for the robot to generate the required forces for perform a candidate dig. Lets say that the excavator in Fig. 4 can develop a maximum of 1000 units of force at the end effector. Also, lets assume that the soil properties are y= 20, @ = 30, c = 5. The constraint surface due to force limitation, given the terrain of Fig. 3, can be seen in Fig. 10.\nC. Search for an r r O p t i d Dig"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002766_j.ijmecsci.2003.09.004-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002766_j.ijmecsci.2003.09.004-Figure5-1.png",
+ "caption": "Fig. 5. Displacement of the excavator caterpillars.",
+ "texts": [
+ " The vectors of position of the centres of weight have the form: rS1 [0; 0; 0]; rS2 [0; \u2212b2; h2]; rS3 [ \u2212 YS3 sin ; (YS3 cos \u2212 b2); ZS3 ]; rS4 [ \u2212 YS4 sin ; (YS4 cos \u2212 b2); ZS4 ]; rS5 [ \u2212 YS5 sin ; (YS5 cos \u2212 b2); ZS5 ]; (43) where YS3 = b3 + b4 cos 1 \u2212 h4 sin 1; ZS3 = h3 + b4 sin 1 + h4 cos 1; YS4 = b3 + lw cos 1 + b5 cos( 2 \u2212 1) + h5 sin( 2 \u2212 1); ZS4 = h3 + lw sin 1 \u2212 b5 sin( 2 \u2212 1) + h5 cos( 2 \u2212 1); YS5 = b3 + lw cos 1 + lr cos( 2 \u2212 1) + b6 cos( 2 + 3 \u2212 1) + h5 sin( 2 + 3 \u2212 1); ZS5 = h3 + lw sin 1 \u2212 lr sin( 2 \u2212 1) \u2212 b6 sin( 2 + 3 \u2212 1) + h6 cos( 2 + 3 \u2212 1): The potential energy from the forces of gravity for the whole system with a non-deformed soil foundation is Vg(q) = (m1 + m2 + m3 + m4 + m5)g \u00b7 z + m2g(h2 \u2212 \u20191b2) +m3g(ZS3 + \u20191YS3 cos \u2212 \u20191b2 + \u20192YS3 sin ) +m4g(ZS4 + \u20191YS4 cos \u2212 \u20191b2 + \u20192YS4 sin ) +m5g(ZS5 + \u20191YS5 cos \u2212 \u20191b2 + \u20192YS5 sin ): (44) A soil foundation has been treated as a homogeneous body whose strain results from the pressures transferred by the caterpillars onto the foundation. It has been assumed that the caterpillar is supported in the chassis frame and during the pressure constitutes a rigid plate interacting with the foundation, as shown in Fig. 5. Denoting equivalent rigidities of a soil as super=cial ones in a vertical direction cz [(N=m2)=m], and linear ones in a horizontal direction cx and cy (N/m), the potential energy of the deformed soil foundation was determined. This energy is Vs(q) = cz \u00b7 a \u00b7 b[z2 + 1 12 \u2019 2 2(3a2 1 + a2) + z \u00b7 \u20191(b02 \u2212 b01) + 1 3 \u2019 2 1(b2 02 \u2212 b01b02 + b2 01)] +1 2 cx[2 \u00b7 x + \u20193(b01 + b02)]2 + 1 2 cy[2 \u00b7 y2 + 1 2 \u2019 2 3(a1 + a)2]: (45) It has been assumed that during the strain a soil foundation is subjected to energy dissipation, which is described by a Rayleigh dissipation function of the form: D(q; q\u0307) = 1 2 k\u2211 i=1 k\u2211 j=1 Rijq\u0307iq\u0307j: (46) Following the determination of rate of strain of the foundation resulting from displacements of the chassis with its caterpillars, the dissipation function of the system of the following form was determined: D(q\u0307) =Rza \u00b7 b[z\u03072 + 1 2 \u2019\u0307 2 2(3 \u00b7 a2 1 + a2) + z\u0307 \u00b7 \u2019\u03071(b02 \u2212 b01) + 1 3 \u2019\u0307 2 1(b2 02 \u2212 b01b02 + b2 01)] + 1 2 Rx[2 \u00b7 x\u0307 + \u2019\u03073(b01 + b02)]2 + 1 2 Ry[2 \u00b7 y\u0307 2 + 1 2 \u2019\u0307 2 3(a1 + a)2]: (47) Non-potential generalized forces result from cutting forces that are formed on the edge of the bucket during operation of an excavator"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003259_robot.2004.1307509-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003259_robot.2004.1307509-Figure1-1.png",
+ "caption": "Fig. 1. Gnspless Manipulation",
+ "texts": [],
+ "surrounding_texts": [
+ "I. INTRODUCTION\nManipulation without grasping is referred to as graspless manipulation [I] or nonprehensile manipulation [2]. In this paper, we study graspless manipulation where the manipulated object is supported not only by robot fingers but also by the environment; it includes pushing, sliding and tumbling (Fig. I). Graspless manipulation brings the following advantages to robots:\nManipulation without supporting all the weight of the\n. Manipulation with simple mechanisms Manipulation - when grasping is impossible object\nThus graspless manipulation is important as a complement of conventional pick-and-place to enhance the dexterity of robots.\nPlanning of robot motions to move an object from an initial configuration to a goal is a fundamental problem in robotic manipulation. However, robot motion planning for graspless manipulation is much more difficult than that for pick-and-place 131. In pick-and-place operation, once an object is grasped, the correspondence of its motion to the robot motion is trivial: therefore manipulation planning is reduced\nto a geometrical collision avoidance. On the other hand, the correspondence in graspless manipulation is nontrivial; thus manipulation planning requires mechanical analysis for consideration of the effect of gravity, contact forces, and so on. Moreover, graspless manipulation may be irreversible: For example, a robot can push an object but may not be able to pull it back. Therefore, most of related studies deal with planning of manipulation with a specific operation such as pushing (e.g.,\nThe authors proposed a planning method for general graspless manipulation by multiple robot fingerhps 131. However, the method can deal with only planar graspless manipulation. In this paper we extend our previous method. The main improvements are as follows: . Now it can deal with spatial graspless manipulation such\nas pushing and tumbling of a polyhedron by multiple robot fingertips. . Control modes of robot fingers (force controllposition control) are considered explicitly for realistic manipulation. . A new stability measure 16) is adopted in planning lo generate robuster graspless manipulation. . A* algorithm [7] is used to accelerate planning.\nThis paper is organized as follows: Section 11 introduces a model of graspless manipulation. Section U1 describes a method to determine appropriate finger control modes (force control or position control) at an instant in graspless manipulation based on 181. Section N proposes a method of motion planning of robot fingertips for graspless manipulation. In Section V, some examples of planned graspless manipulation including pushing and tumbling are presented. We also show an experimental result of execution of planned manipulation by a robot with a multi-fingered hand. Finally, this paper is concluded in Section VI.\n141,151).\n11. MODEL OF GRASPLESS MANIPULATION A. Assumptions\nfingertips, we make the following assumptions: In this paper, for graspless manipulation by multiple robot\nI ) The manipulated object, robot fingertips, and the environment are rigid.\n07803-8232-3/04/$17.00 @004 IEEE 2951",
+ "object motion is specified. We approximate each friction cone at contact point p by a polyhedral convex cone with unit edge vectors, cl(p), . . . , c.(p) E R3. For p,,,, E Csiide. let c'(penv,) E P3 be a unit edge vector of the friction cone at contact point p,,, , opposite to its sliding direction.\nThe set of possible contact force f E L3 at p,,, can be written as follows:\n{flf E sPan{cl(P,,\",),...,c,(P,,,)}} if P,\"\", E cstat .\n{flf E sPan{c'(P,\"\",)l} if P,, E Cslide,\n(1)\nwhere span{. . .} is a polyhedral convex cone spanned by its element vectors [9]. On the other hand, the set of possible finger force f at probl is: 2) Manipulation is quasi-static. 3) Coulomb friction exists between the object and the environment (or robot fingertips). The friction coefficient f { f l f E span{q(prob,), .. . , cs(prob,)}, ~.\nn ( ~ m b i ) ~ f If m a x i }\nif robot finger i is position-controlled, (2) {flf E span{cl(probi),...,cB(PTObi)}) 1 n(pr&()Tf f c o m i S ' f m a x i } .\non a contact surface is uniform. 4) Static and kinetic friction coefficients are equal. . ~ 5 ) All the contacts can be approximated by finite point\n6) Each of friction cones can be approximated by a poly-\n.\ncontacts [6] ;\nhedral convex cone [9]. I if robot fineer i is force-controlled, - 7) Each robot finger is modeled as a rigid sphere and- is where fm, , is the upper4imit of the normal component of\nin- onemint non-sliding contact with the 0bject;'we the finger force and f c o m i is the commanded force for .. robot finger i. . . consider only fingertips.\n8) Thenormal force of each robot finger has an upper limit. 9) Each robot fineer is either in Dosition-control mode or Then we define the following matrices: I\nin force-control mode. IO) Each of robot fingers in position-control mode'can apply\narbitraly force passively within its friction cone. -1 1). Each of robot fingers in force-control mode is in hybrid\npositionlforce control [10]:- the finger can apply commanded normal force actively and arbitrary ,tangential force passively within. its friction cone. 12) sliding and,rolling of robot fingers on object surfaces is not allowed. Regrasping is required to change the location of fingertips on the object.\nThe problem to be solved is to determine a sequence of fingertip positions and finger control modes to move an object from a given initial configuration to a given goal configuration by graspless manipulation. A sequence of desired normal forces is also to be obtained for forcesontrolled fingers.\n8. Mechanical Model\n-. ~~\n'\nI .\nConsider graspless manipulation of an object a s in Fig. 2. We set an object reference frame whose origin coincides with the center of mass of the object. Let pen, . . ,p,,, E @ be positions of contact points between .the object and the environment. ,Similarly, let probI, . .. ,probn, E? be positions of contact points between the object and the robot finger 1,. . . , n. We denote inward unit normal .vectors at contact point p by n(p) E @.\nLet us denote-the sets of positions of sliding and nonsliding contacts by Cslid& and CStat, respectively. We can identify whether p,,, E Cslide or penvi E CSw when the\nI if P,,,, E Cslide.\nCrab :=diag(C,,b1,...,Crobn) E %3\"xns\nCrobt := [cl(probl). . .Cs(Probt)l E pX' N m b := diag(n(P,bi), . . . I n(Probn)) E enxn,\nwhere I 3 is the 3 x 3 identity matrix, and p x 1 3 E P x 3 is a linear transformation equivalent to the cross product with p.\nWithout external disturbances, the equilibrium equation of the object can be expressed as:\nQknown + WenvCenvkenv + Wrobcrobkrob = 0, (3) where ken\"(> 0) and krob(> 0) are coefficient vectors to represent contact forces; Qknown E L6 is a known external (generalized) force applied to the object such as gravitational force. The upper limitation on the magnitude of normal finger forces can be written as:\nNTobCrobkrob 5 f,, (4)\nwhere f, := [ f m a x l , . . . , f m a x n l T E Ln."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001039_960485-Figure16-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001039_960485-Figure16-1.png",
+ "caption": "Fig. 16 : New hydraulic brake actuator under development",
+ "texts": [
+ " 15 shows the occurrence frequency of the steering wheel angular velocity for the pylon slalom condition mentioned above. The driver steered very quickly to keep the vehicle stable for the test without ASTC. However, ASTC reduces the driver's required steering reaction time to keep the vehicle stable. Pylon slalom test Vxo = 27.8 m/sec 5 10 Steering wheel angular velocity (rad/sec) Fig. 15 : Histogram of steering wheel operation (Experimental) NEW HYDRAULIC BRAKE ACTUATOR A drawing of a new hydraulic brake actuator under development as a future product is shown in fig. 16. This is smaller and 50 % lighter than a conventional hydraulic booster with ABS and traction control. This hydraulic brake actuator is not only applicable to ASTC but also to brake assist and adaptive cruise control, with minor modifications. SUMMARY (1) Vehicle directional stability in a transient steering maneuver has been studied. It was found that applying an active brake force to the front-outer wheel stabilizes the vehicle since an outward yaw moment is generated. (2) The effect of controlling the brake force response was evaluated by simulation and experiment to determine the brake actuator response criteria"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002867_s0094-5765(03)00194-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002867_s0094-5765(03)00194-2-Figure1-1.png",
+ "caption": "Fig. 1. Experimental spacecraft on-orbit conGguration.",
+ "texts": [
+ " The largest error quaternion vector components [ qerr1(t) qerr2(t) qerr3(t) ] are compared to its precomputed values at the halfway mark (qhalf ) to determine if the maneuver time reaches th: max i |qerri(t)| \u2212 qhalf = { \u00bf 0 \u2200t \u00a1 th ; \u00a1 0 \u2200t \u00bf th ; (25) where Iqerr = qerr0 qerr1 qerr2 qerr3 = qr0 qr1 qr2 qr3 \u2212qr1 qr0 qr3 \u2212qr2 \u2212qr2 \u2212qr3 qr0 qr1 \u2212qr3 qr2 \u2212qr1 qr0 q0 q1 q2 q3 ; (26) qhalf = maxi|qerri(0)| |sin( =2)| \u2223\u2223\u2223\u2223sin ( 4 )\u2223\u2223\u2223\u2223 : (27) In order to demonstrate the superiority of the proposed minimum-time SMC algorithm, we further adapt the eigenaxis quaternion regulator: * T = * M + Kqvec + D * !: (28) It has been shown in Ref. [2] that an eigenaxis rotation will occur when K = k diag( II) and D = d diag( II), where k and d are positive constants. A typical remote sensing spacecraft system is used as an example. Fig. 1 depicts the remote sensing spacecraft on orbit conGguration. The large angle maneuver of interest is speciGed in terms of Euler angles as shown in Table 1, with II = diag[ 182 329 336 ] kg m2. The maneuver on yaw is null for the most Earth-pointing remote sensing cases. The conGguration of reaction wheels in the simulated spacecraft has been deliberately arranged to accommodate the capability of fast attitude maneuver. According to the wheel conGguration, the maximum wheel torque Nsat = [ 0:56 0:52 0:24] N m, maximum wheel speed max = 5400 rpm, and MOI of wheel Iw = 0:041 kg m2 are used in the simulation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001127_s0022112002002483-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001127_s0022112002002483-Figure10-1.png",
+ "caption": "Figure 10. Four computed menisci (\u00a7 4.1), A1\u2013A4, between two curved plates, S1 and S2, for given normalized heights h1 = 1.5 and h2 = \u22121.0 of the triple points are shown. The plates are curved such that, at the triple (solid\u2013liquid\u2013vapour) points, the angle of the menisci with the vertical can take appropriate values necessary to form four different menisci, and yet satisfy the fixed contact angle with the solid. The outer menisci are computed by the procedure outlined in \u00a7 3.4. The interaction force between S1 and S2 (in (e)) is repulsive at all non-dimensional distance, x0, between the triple points. There are four solutions for the force originating from two bifurcation points B1 and B2. The points A1\u2013A4 correspond to the menisci shown in (a)\u2013(d ). The energy (hydrostatic and surface) as a function of x0 is shown in ( f ). A numerical derivative of the lowest energy with respect to x0 coincides with the corresponding force\u2013distance curve of (e) as expected.",
+ "texts": [
+ " Thus, A is the lowest or the highest point of the meniscus. Then, by (4.7), where y and h0 have opposite signs, \u03b8\u2032 6= 0 at any point on the meniscus. For the former family, let \u03b8\u2032 = 0 at B on the meniscus. Then, h(B) = 0 and \u03b8(B) 6= 1 2 \u03c0. At any point of the meniscus below the far-field liquid surface, \u03b8\u2032 < 0 and above the far-field liquid surface, \u03b8\u2032 > 0 (equation (4.1)). Thus, if there exists a point, A\u2032, on the meniscus where the tangent is horizontal, then the liquid is above A\u2032 (see e.g. figure 10). Thus, the two families are mutually exclusive. 4.5. Formation of clusters by floating plates: is there a critical size for sinking? Solids, floating on liquids, are known to agglomerate owing to interaction forces between them. The shape and size of a cluster formed by floating plates depend on the size and shape of the plates and their initial states. The weight of the cluster is the sum of the weights of the individual plates, but the perimeter of the cluster is less than the sum of the perimeters",
+ "3 that for a prescribed height, there are at most two possible menisci between the edge of a single plate and a liquid. Thus, for the meniscus between two plates (two edges are involved) there are at most four possible menisci for given prescribed heights of the triple points. However, the four solutions will result in four different horizontal gaps, x0, between the plates. Figures 10(a)\u201310(d ) show the four possible menisci formed between two solids, S1 with h1 = 1.5 and S2 with h2 = \u22121. The angle of the menisci at L1 with the vertical, \u03b81, is close to \u2212 1 2 \u03c0 (in figure 10(a), \u03b81 > \u2212 1 2 \u03c0, in 10(b), \u03b81 < \u2212 1 2 \u03c0). Thus, the menisci are close to the bifurcation point \u03b81 = \u2212 1 2 \u03c0. Note that the solids are curved at the edges so that they allow \u03b81 and \u03b82 to take required values to sustain the menisciL1L2 that maintain the fixed contact angle \u03c6 between the solid and the liquid. Figure 10(e) shows the four bifurcation branches of the solution for the repulsive interaction force between the two solids as a function of the horizontal gap, x0 (non-dimensional), between L1 and L2. The equal interaction force for the menisci A1 \u2212 A4 are shown by the ordinate of the line A1A4 in figure 10(e). Each pair of menisci, such as A1 and A2, originate from a bifurcation point such as B1 where \u03b81 = \u2212 1 2 \u03c0. The pair, A3 and A4, originate from B2 where \u03b82 = \u2212 1 2 \u03c0. Figure 10( f ) shows the energy associated with the four possible menisci as a function of x0. In calculating the hydrostatic part of the energy, the width of each of the plates in non-dimensional units is taken as 2w = 2. The energies corresponding to the four menisci A1\u2013A4 are represented by the filled circles A1\u2013A4 in figure 10( f ). The lowest energy curve is differentiated with respect to x0 numerically and the result is plotted on the force diagram. It matches the corresponding force curve as expected. Figures 11(a)\u201311(d ) show the four possible menisci between two solids S1 and S2 with h1 = 1 and h2 = 2, respectively. Note that h = 2 is the maximum allowable height (see (3.5) and the following paragraph) of the meniscus mR on the right-hand side of S2 with an angle \u03b8R = \u2212 1 2 \u03c0 at the triple point LR . Figure 11(e) shows the interaction force, Fx/\u03b3, which is attractive for all x0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.11-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.11-1.png",
+ "caption": "Figure 3.11. The displacement due to a pure rotation about an axis at 0 is equal to the dis placement due to the same rotation about a parallel axis at 0* and a translation b* perpen dicular to the axis of rotation.",
+ "texts": [
+ "138) for a pure rotation about 0 can be accomplished by a translation b* perpen dicular to the axis a= k together with the same rotation about a parallel axis through 0*. Since T is the same as before, the rotational part of the dis placement of P about 0* is given as (3.139) 196 Chapter 3 Thus, use of (3.138) and (3.139) in (3.137) yields b* =d(P)-Tx*(P)= ( -i + j)- ( -2i + 2j) = (i- j) ft, which is certainly perpendicular to a. This is the required translational displacement of 0* in qJ. The reader may confirm that the translation b* obtained from (3.137b) yields the same result. The dis placement is illustrated in Fig. 3.11. Notice that b* is simply the chord dis placement of 0* on the circle of radius 00* due to a pure rotation about 0. A displacement of a rigid body .19 each of whose particles is displaced parallel to a given plane is called a plane displacement of !JI. Any plane cross section of !JI parallel to the assigned plane, which is named the displacement plane, may be chosen as the plane for discussion; it requires no special dis tinction. It follows that the axis of rotation must be perpendicular to the dis placement plane"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure8-1.png",
+ "caption": "Fig. 8. The undeformed and deformed con\u00aegurations of an in\u00aenitesimal reference surface of a general two-dimensional structure.",
+ "texts": [
+ " 7(b) that f ~f 1 ~f 2 ~f 3 danrjr trsjrjs danrtrsjs 59 It follows from Equations (57), (58a)\u00b1(c) and (59) that s\u0302 S F T J\u0302 T , t 1 F F s\u0302 60 Using Equations (3), (8), (20), (42a) and (60), we obtain the following relationships: S s\u0302 F \u00ffT F F \u00ff1 t F \u00ffT, J\u0302 s\u0302 T T S U , J 1 2 J\u0302 J\u0302 T 1 2 S U U S , s 1 2 s\u0302 s\u0302 T 61 These relationships are the same as those obtained in Atluri [1]. However, the presented derivations clearly show the directions of di erent stresses. For highly \u00afexible structures undergoing large displacements and rotations but small strains, Jaumann strain measure is the most appropriate one for use because Jaumann strains are shown to be objective geometric measures de\u00aened with respect to the rigidly rotated undeformed area. Next we show how to use Jaumann strains and stresses in the modeling of highly \u00afexible two- dimensional structures. Figure 8 shows the undeformed and deformed con\u00aegurations of an in\u00aenitesimal reference surface of a general two-dimensional structure. To simplify derivations and explanations, we adopt the Kirchho hypothesis and hence neglect transverse shear deformations and transverse normal strain in the following derivations. The system xyz corresponds to the system x1x2x3 in Figs 1\u00b17 and is an orthogonal curvilinear coordinate system with the curvilinear axes x and y being on the undeformed reference surface and the z-axis being a rectilinear axis",
+ " We also let i1\u00c3 and i2\u00c3 denote the unit vectors along the axes x\u03021 and x\u03022, respectively. Jaumann strains can be easily obtained by using the concept of local displacements [21, 24]. The local displacement vector u of an arbitrary point on the shell element has the form u ukik 62a where u1 x, y, z, t u01 x, y, t z y2 x, y, t \u00ff y02 x, y , u2 x, y, z, t u02 x, y, t \u00ff z y1 x, y, t \u00ff y01 x, y , u3 x, y, z, t u03 x, y, t 62b Here, uk 0 are the displacements (with respect to the frame x1x2x3) of the reference point A' in Fig. 8, y1 and y2 are the rotation angles of the observed shell element with respect to the axes x1 and x2, respectively, and y1 0 and y2 0 are the corresponding initial rotation angles. Because the frame x1x2x3 is a local coordinate system attached to the observed shell element, and the x1\u00b1x2 plane is tangent to the deformed reference surface, we have u01 u02 u03 y01 y02 y1 y2 @u03=@x @u03= @y 0 63 It follows from Fig. 8 that @u02 1 e1 @x sin g61, @u01 1 e2 @y sin g62 64a @u01 @x 1 e1 cos g61 \u00ff 1, @u02 @y 1 e2 cos g62 \u00ff 1 64b @y02 @x \u00ff @ j1 @x j3 k01, @y01 @y \u00ffk02, @y01 @x \u00ff k061, @y02 @y k062 64c @y2 @x \u00ff @ i1 @x i3 k1, @y1 @y \u00ffk2, @y1 @x \u00ff k61, @y2 @y k62 64d where kij are deformed curvatures and kij 0 are undeformed curvatures. Substituting Equations (62a)\u00b1 (b), (63), (64a) and (64b)\u00b1(d) into Equation (21) yields the Jaumann strains of a general shell struc- ture as B11 1 e1 cos g61 \u00ff 1 z k1 \u00ff k01 , B22 1 e2 cos g62 \u00ff 1 z k2 \u00ff k02 , B12 1 2 1 e1 sin g61 1 e2 sin g62 z k6 \u00ff k06 , B33 B13 B23 0 65 where k60k61+k62 and k6 00k61 0 +k62 0 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001324_rsta.2002.1155-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001324_rsta.2002.1155-Figure1-1.png",
+ "caption": "Figure 1. The geometry of simple shear experiment with three principal orientations, labelled V , G and D, for the initial nematic director n aligned along the vorticity, gradient and displacement directions, respectively. The small-amplitude simple shear \" \u00bb ei!t is applied to the elastomer, and the measured stress \u00bc (!) provides the linear complex modulus in each of the three con\u00afgurations.",
+ "texts": [],
+ "surrounding_texts": [
+ "The dynamic equations are obtained from the classical variational principle applied to the proper Lagrangian density amended by the Rayleigh dissipation function, L \u00a1 T _s = 1 2 \u00bb (@tu)2 \u00a1 F (u; \u00a3) \u00a1 T _s( _u; _\u00a3). The elastic potential energy density in a nematic rubber takes the form (de Gennes 1980) F = C1(n \u00a2 \" \u00a2 n)2 + 2C2 Tr[~\"](n \u00a2 \" \u00a2 n) + C3(Tr[~\"])2 + 2C4[n \u00a3 \" \u00a3 n]2 + 4C5[n \u00a3 \" \u00a2 n]2 + 1 2 D1[n \u00a3 \u00a3]2 + D2n \u00a2 \" \u00a2 [n \u00a3 \u00a3]; (2.1) Phil. Trans. R. Soc. Lond. A (2003) with \"ik = ~\"ik \u00a1 1 3 Tr[~\"] \u00af ik, the traceless part of linear symmetric strain ~\"ik = 1 2 (@kui + @iuk). In the isotropic limit C1 = 2C4 = 2C5 ! \u00b7 \u00ba cxkBT (the rubber modulus, proportional to the crosslinking density cx) and the elastic energy density reduces to the classical Lam\u0301e expression \u00b7 \"ik\"ki + B\"2 kk . In the fully incompressible case one should omit the C2 and C3 \u00ba B terms in (2.1). Since rubber is a weak solid, its shear moduli are much smaller compared with those involving compression and we thus now ignore the e\u00acects of volume change. Neglecting the e\u00acects of heat convection, the total entropy production in a uniaxial anisotropic medium is expressed by the volume integral of the conjugate forces and \u00aeuxes. Let us rewrite the density of dissipation function in a form matching the elastic energy density (2.1) T _s = A1(n \u00a2 _\" \u00a2 n)2 + 2A4[n \u00a3 _\" \u00a3 n]2 +4A5([n \u00a3 _\" \u00a2 n])2 + 1 2 \u00ae 1N 2 + \u00ae 2n \u00a2 _\" \u00a2 N (2.2) in the incompressible case, where the Leslie{Ericksen notation reads N = [n \u00a3 _\u00a3]. Here the constants are linear combinations of the classical Leslie coe\u00af cients of a nematic elastomer medium: A1 = 1 2 ( \u00ac 1 + \u00ac 4 + \u00ac 5 + \u00ac 6); A4 = 1 4 \u00ac 4; A5 = 1 8 (2\u00ac 4 + \u00ac 5 + \u00ac 6): In the isotropic limit, one nds A1 = 2A4 = 2A5 ! \u00b2 . By di\u00acerentiation of (2.2) by the symmetric strain rate _\"ij and by _\u00a3 i, respectively, one obtains a representation of the symmetric viscous stress tensor and the nematic molecular eld, contributing to the local viscous torque (Terentjev & Warner 2001). Two important non-dimensional numbers control the regimes of \u00aeuid dynamics in nematic liquids: the Reynolds number Re and the Ericksen number Er. In elastomers and gels, one is much more concerned with the balance between \u00aeow-induced torques, scaling as \u00b9 \u00b2 rv, and those of the rubbery matrix, expressed by @F=@\u00a3 \u00b9 D1\u00a3. This yields a new dimensionless group of parameters characterized by the number Ne = \u00b2 v=(LD1), with L the characteristic length-scale. The assumed domination of rubber-elastic e\u00acects over the nematic Frank (curvature) elasticity essentially means that D1 \u00be K=L2, that is, Ne \u00bd Er. There is a clear parallel between the form of equilibrium potential energy density (2.1) and the dissipation function (2.2): Ai $ Ci and \u00ae 1;2 $ D1;2. This is not a surprise since the symmetry of an equilibrium elastic deformation at constant volume and of a slow viscous \u00aeow in a uniaxial continuum is the same. Equally, there is a direct correspondence in the dependence of the various coe\u00af cients on nematic order parameter Q. We can, therefore, represent the viscous coe\u00af cients of a nematic elastomer as products of the corresponding rubber-elastic constant and an appropriate relaxation time, that is Ai = Ci \u00bd R; \u00ae 1 = D1 \u00bd 1; \u00ae 2 = D2 \u00bd 2: (2.3) Relaxation times \u00bd R do not have to be equal for each pair of coe\u00af cients, however; one can expect them all be of the same order of magnitude|of the order of Rouse time for the corresponding polymer backbone (Edwards et al . 2000). Two orientational relaxation times, \u00bd 1;2, describe the dynamics of the nematic director. One expects, in many polymer systems, to nd \u00bd R \u00b9 10\u00a15 s (Doi & Edwards 1986), while the nematic director relaxation time is \u00bd 1 \u00b9 10\u00a12 s from Sch onstein et al . (2001). The demand of Phil. Trans. R. Soc. Lond. A (2003) positive-de niteness of the entropy production imposes a constraint on the values of relaxation times: \u00bd 1 \u00bd R > D2 2 8C5D1 \u00bd 2 2 : (2.4) In the ideally soft nematic elastomer, with C5 = D2 2=8D1, this reduces simply to \u00bd 1 \u00bd R > \u00bd 2 2 . Neglecting in the rst instance the e\u00acects of Frank elasticity on the director gradients, one obtains the set of dynamic equations \u00bb @2 t u = r \u00a2 \u00be s ym \u00b2 @k \u00b5 @F @[rku] \u00b6 + @k \u00b5 @T _s @[rk _u] \u00b6 ; (2.5) 0 = @F @\u00a3 + @T _s @ _\u00a3 : (2.6) Here the rst equation describes the balance of forces per unit volume acting at a material point. We shall neglect the inertial term \u00bb u, relevant only in higherfrequency acoustic e\u00acects (Terentjev et al . 2002). The second equation represents the balance of torques, of elastic and viscous origin. The local moments of inertia are neglected in (2.6): at low frequencies and \u00aeow rates this is well justi ed in classical hydrodynamics, while, in the high-frequency regime, the polymer transition to the high-frequency glassy modulus would overwhelm the angular inertia. We have discarded the nematic Frank elasticity contribution: if it happens that the nematic rubber penetration length is not small, K=\u00b7 L2 \u00b9 1 (e.g. in highly diluted gels or very thin samples), then the torque balance will be controlled by the full molecular eld. Equation (2.6) transforms to [n \u00a3 hfu ll] = 0, with the molecular eld hfu ll \u00ba Kr2 \u00af n + D1\u00a3 + D2n \u00a2 \" + \u00ae 1 _\u00a3 + \u00ae 2n \u00a2 _\": (2.7) In the limit of isotropic rubber, Q ! 0, the only relevant equation is that for the symmetric stress, equation (2.5), which in this case reduces to \u00be = C4\" + A4 _\". This is the low-frequency limit of a general linear-response expression \u00bc (t) = Z G(t \u00a1 t0) _\"(t0) dt0: In the frequency domain, this limit of a general complex modulus G \u00a4 (!) ! Ci +i!Ai shows the initial rise in the loss modulus with frequency. The condition of zero net torque determines the rate of relative director variation _\u00a3 . In a xed coordinate system, for instance with the initial director n along the z-axis, and assuming oscillatory solutions so that d=dt ) i!, this is straightforward: \u00b5 \u00a3 x \u00a3 y \u00b6 = D2 + i!\u00ae 2 D1 + i!\u00ae 1 \u00b5 \u00a1 \"yz \"xz \u00b6 : (2.8) Substituting it into the corresponding components of stress \u00be s ym , one obtains the e\u00acective viscoelastic response. This operation, known as the integration out of the internal degrees of freedom, is precisely what has been done (Golubovi\u0301c & Lubensky 1989; Olmsted 1994) in the analysis of equilibrium soft elasticity. Here it is complicated by the viscous terms, but the essence remains the same: the e\u00acective shear Phil. Trans. R. Soc. Lond. A (2003) modulus is renormalized to CR 5 (!) = C5 \u00a1 D2 2 8D1 (1 + i!\u00bd 2)2 (1 + i!\u00bd R)(1 + i!\u00bd 1) : (2.9) Clearly, at any non-zero frequency there will no longer be a complete `soft\u2019 cancellation leading to CR 5 = 0. However, a reduction of the e\u00acective elastic modulus will nevertheless occur. The three principal shear geometries of classical dynamic mechanical experiments are shown in gure 1. The three cases are labelled according to the orientation of the initial uniformly aligned director n with respect to the shear direction. These three geometries are the same as in the classical setting for Miesovicz viscosity experiments (de Gennes & Prost 1993). The elastic free energy density, equation (2.1), takes the form, FG = (C5 + 1 8 [D1 \u00a1 2D2]) \"2 \u00a1 1 2 (D1 \u00a1 D2) \"\u00b3 + 1 2 D1 \u00b3 2; F D = (C5 + 1 8 [D1 + 2D2]) \"2 \u00a1 1 2 (D1 + D2) \"\u00b3 + 1 2 D1 \u00b3 2; FV = C4\"2; 9 >= >; (2.10) in the three cases of gure 1, where the amplitude of the small change in director orientation, \u00af n, is taken equal to the angle \u00b3 . Clearly, one does not expect director rotation to occur in the `log-rolling\u2019 geometry V . The analysis (Terentjev & Warner 2001) gives the linear `nominal stress\u2019 at a given frequency of imposed simple shear strain, \u00bc (!) = G \u00a4 (!)\"(!), with the linear complex shear modulus G \u00a4 = G0 + iG00. The linear response in the two geometries involving n-rotation, G and D, is exactly the same despite the di\u00acerence in the rotation angles \u00b3 G; D . These storage and loss moduli have a single-relaxation time behaviour with a characteristic frequency !1 = D1=\u00ae 1 and can be written in a universal form: G0(!) = 2 \u00b5 C5 \u00a1 D2 2 8D1 \u00b6 + (!\u00bd 1)2 1 + (!\u00bd 1)2 D2 2 4D2 1 \u00b5 1 \u00a1 \u00bd 2 \u00bd 1 \u00b62 ; G00(!) = !\u00bd 1 1 + (!\u00bd 1)2 D2 2 4D2 1 \u00b5 1 \u00a1 \u00bd 2 \u00bd 1 \u00b62 + 2!\u00bd 1 \u00b5 D2 2 4D1 \u00b5 \u00bd 2 \u00bd 1 \u00b62 \u00a1 C5 \u00bd R \u00bd 1 \u00b6 : 9 >>>>= >>>>; (2.11) The `non-soft\u2019 V geometry returns a trivial sum of the elastic and viscous parts, G \u00a4 V(!) = 2C4 + 2i!A4 \u00b2 2C4(1 + i!\u00bd R); (2.12) which is simply the low-frequency limit of the classical isotropic polymer dynamics. Figure 2b shows the qualitative sketch of the storage modulus (the real part, G0) Phil. Trans. R. Soc. Lond. A (2003) of an ordinary polymer network. To make the simple conceptual point, this plot ignores more complicated e\u00acects, such as entanglements, and only expresses the role of Rouse dynamics. Thus, at ! ! 0 the isotropic modulus approaches the constant value G0 = 2C4 \u00b2 \u00b7 , which is of course the equilibrium rubber modulus. At !\u00bd R \u00b9 1 one nds the dynamic glass transition (often called the \u00ac -transition). The shear modulus saturates at a very high (glass) value at high frequencies. The main content of the gure 2 is given by the two plots ( gure 2a) which show the frequency dependence of G0 and G00, expressed by equations (2.11) in the two director-rotating geometries, G and D. One nds the classical single-relaxation behaviour with the characteristic time-scale \u00bd 1 = \u00ae 1=D1. At !\u00bd 1 \u00be 1 (assuming this is still much lower than the dynamic glass transition), the storage modulus saturates at the constant level of the modi ed rubber plateau, given by equation (2.11), while the loss modulus begins its linear rise towards the glass transition peak. More interesting is the behaviour at !\u00bd 1 \u00bd 1. Here we see a substantial drop in the storage modulus due to the internal director relaxation: the e\u00acect of `dynamic soft elasticity\u2019. The family of curves G0(!) in gure 2a is drawn for the increasing nematic order parameter Q, which enters into the elastic constants and the Leslie coe\u00af - cients: we see the increasing drop in G0 and also the rise of the new loss peak in G00 at !\u00bd 1 \u00b9 1. Phil. Trans. R. Soc. Lond. A (2003)"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001635_3.20858-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001635_3.20858-Figure8-1.png",
+ "caption": "Fig. 8 Dimensions of the antenna.",
+ "texts": [],
+ "surrounding_texts": [
+ "To validate the theory, two different control designs are presented, i.e., a spring-mass-damper system and a shape and pointing control system for a space antenna. The active controller has been determined in both cases by means of a discrete linear suboptimal control technique,7 and the system response has then been evaluated via an exact nonlinear integration of the equations of motion, to take into account the presence of saturations and PWM actuators. Pulse-width modulated actuators are always assumed to be coupled and acting in opposite directions, the switching between the two being determined by the sign of the firing duration time 6. Example 1: Second-Order System The first test was carried out to demonstrate the effects of the firing delay r, the maximum input amplitude UM, and the D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 sampling time A on the transient and steady-state response of a system subjected to a control input and to a reference command by using the spring-mass-damper system shown in Fig. 2. The dynamics of the system having mass m, damping coefficient c, and elastic spring constant k is represented in the state-space form by *l r-2f\u00ab *H i -o>2 0 the input force (/) is given by (34) (35) where [r] is the desired set point. It can be noted that the feed-forward control, i.e., mu2[r], is capable of achieving the desired set point in case of perfect model knowledge. Thus the feedback terms are added to improve response performances and to take into account uncertainties in the model knowledge. The system parameters are m = 1, f = 0.1, and co = 6.28, i.e., an open-loop natural frequency of 1 Hz. With these system characteristics, a controller sampling time of 0.1 s appears appropriate. Specifications for the closed-loop system are established in terms of damping factor, to be as close as possible to 0.7, and a sufficiently low input requirement to prevent undesirable control saturations in PWM operational mode. To meet the dynamic performances, kv and ke are computed for a PAM control by minimizing the discrete quadratic performance index7: (36) c f Fig. 2 Second-order system. Spring-Mass-Damper System Sampling time 0.1 sec ; no input delay Sampling time 0.1 sec ; optimal input delay 0.0 0.0 0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 Time (sec) Time (sec) Sampling time 0.05 sec ; no input delay Sampling time 0.05 sec ; optimal input delay 1.5 -| 1.0 2.0 3.0 0.0 1.0 2.0 3.0 Time (sec) Time (sec) \u2014\u2014PAM -o-4Jmax = 50 \u2014x-Umox = 200 Fig. 3 Displacement response of second-order system (PAM and PWM). where E {\u2022} indicates the expected value operator for a suitable set of stochastic disturbances and/or nonzero initial conditions, and [Qy] = (37a) (37b) (37c) which leads to kv = -2.67, ke = 24.2. Two different sampling times were then used to analyze the system response, namely A = 0.1 and 0.05 s. Shorter sampling times are not considered since this would mean operating almost as in continuous time, so that PWM control would not be applicable. The optimal firing delay T and the closed-loop eigenvalues are collected in Table 1, whereas the step responses to a unit reference command, either PAM or PWM, with different delays and maximum amplitudes, are reported in Figs. 3-5. In Fig. 5 the PAM input is plotted vs the left ordinate axis, whereas PWM inputs, i.e., duration, are plotted vs the right ordinate axis. Considering Table 1, it should be immediately remarked that, depending on A, the system eigenvalues are not constant. This is not surprising since, because of Eq. (30), both the state transition matrix [$] and input matrix [F] depend on A, whereas in this particular case [K] and [C] are held constant. For the purpose of the present example, this is not important, since the comparisons are done between PAM and PWM responses of analogous systems, with the sampling period as the distinctive parameter of the system configuration. D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 The analysis of the step responses is in good agreement with the theoretical analysis. A few considerations should be noted. As stated in Eq. (8), if the delay is not optimal, the error of the PWM controlled response relative to the \"desired\" response, i.e., the PAM controlled response, is proportional to the input amplitude UM, and this clearly appears from the steady-state biases in Figs. 3 and 4. Moreover, in this particular example, the value UM = 50 is quite close to the steady-state discrete input, which is precisely 39.48. Then it is obvious that the steady-state value of 5 will be quite close to A. This does not agree with the assumptions made to establish the relationship between PAM and PWM control and explains why the performances of the system subjected to a PAM input and to a PWM input with null delay are quite similar. In fact, from Eq. (4), it is seen that, for d = A, the equivalence between PAM and PWM control is obtained with r = 0. Figures 3 and 4 clearly point out the peculiar response of PWM controlled systems. Even at \"steady state,\" the system tends to oscillate around the average condition, due to the on/off input type, and the only reduction in amplitude is due to the integral action of the system dynamics. From Fig. 5 it can be seen that the PWM is always of the same sign. Thus the limit cycles are due only to the elastic action of the system and not to a change of sign of the control force. This fact also explains why the limit cycle amplitude is larger for the higher input level. In fact, since the pulse intensity is equivalent, the duration is shorter for the higher input, and thus it leaves more time for the elastic action to operate, causing a larger amplitude oscillation. The optimum firing delay r guarantees that the steady-state response of the PAM and PWM controlled systems are the same. The difference in the transient response depends on the input amplitude. Higher amplitudes mean smaller pulse firing durations 6, and so the approximation of Eq. (6) becomes indeed true, and Eq. (7) represents the real dynamic behavior of the system, so that the optimal firing delay effectively minimizes the response error. The same holds also for smaller sampling periods since, as shown by Eq. (5), d is also proportional to A. Considering that in discrete control the sampling time is usually limited by the control hardware and cannot therefore be made as small as possible, it can then be stated that it is advisable to select the optimal firing delay for PWM control and, compatible with actuator limits, operate with a sufficiently high input level. Example 2: Shuttle-Attached Antenna The second example shows an application of a mixed PAM/ PWM control to the shape and pointing control of a large space antenna. This system is clearly more complex than the preceding one, and since the antenna structural damping is neglected and the overall system is a free body, it is open-loop neutrally stable. Nevertheless, it will be shown that the equivalent PWM control can be successfully applied also to this kind of system. The antenna studied in the present work consists of a large dish connected to the Shuttle by an aluminum L-shaped flexible truss.8 Figures 6-8 depict the topology and dimensions of the antenna, along with its finite element representation consisting of 95 grid points. Three representative points are marked in Fig. 7, and their dynamic behavior will be used to assess the performance of the system, i.e., node 480 at the corner of the flexible truss, node 751 at the center of the dish, and node 920 on the dish boundary. The flexible truss is considered to be clamped to the Shuttle. All of the elements are supposed to be uniform tubular beams with a cross-sectional area of 200 mm2, Young's modulus equal to 72,520 D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 N/mm2, and density 3000 kg/mm3. The total mass of the antenna is 635 kg, and the total system mass is 102,788 kg. The system dynamics are governed by two sets of equations, one governing the average rigid body motion and another governing the small perturbations of the rigid motion and the elastic deformations. A detailed derivation of the equations of motion is found in the literature9'10 and will not be repeated here for the sake of conciseness. Instead, attention is focused on the small perturbed overall motion and on the elastic deformations as represented by the simplified system (38) in which only two coupling terms [A] and [\u00a3] are present. In Eq. (38), [V] is the matrix of the antenna branch modes, i.e., the modes of the antenna clamped to the still standing Shuttle; [70] and [m] are the inertia and mass matrices of the system in the undeformed condition; {/?) , {/3) , and {q} are, respectively, the perturbed displacement and orientation of the system center of gravity and the antenna branch modal coordinates. It is possible to reformulate Eq. (38) as a set of first-order linear differential equations, with state vector [ x ] , state matrix [A], input vector [u ) , and input matrix [B] given by (39a) V'QiV (39b) 0 J 0 0 0 0 0 0 0 0 X2 lx] + [Rift #i 0 q\\ To -MI A ] = [ Vf ] = m 0 F'A ' 0 Io V'T, 0 r > 1\u0302 J J AF E 'V I { u } = [F, (39d) The branch mode shapes corresponding to the lowest 10 eigenfrequencies were used to represent the antenna. This restricted choice of natural mode shapes is considered accurate enough since, as illustrated in Table 2, they are representative of a wide class of possible motions of the antenna. The analysis of the eigenvalues of the [A] matrix of Eq. (39), also reported in Table 2, shows that basically the coupling has the effect of modifying the flexible branch modes that nonetheless are enough to correctly represent the lowest vibration modes of the whole system since, due to the massive Shuttle, the last branch modes are practically the vibration modes. The control system consists of 23 actuators driven in a decentralized way from collocated sensors. Six of them exert forces and moments on all six degrees of freedom of the rigid Shuttle; eight thrusters are placed on the flexible truss: four on the truss corner acting in the X and Y directions and four at the end acting in the Y and Z directions. The corresponding sensors are local displacement and velocity sensors. The control of the dish is carried out by using three reaction wheels, acting along the three axes at the connection with the truss, driven by angle and angular rate sensors and by six piezoelectric layers on the dish's outer radial beams, marked in Fig. 7 as Pi-P6- The piezoelectric layers are supposed to work in couples, one acting as an actuator and one as a sensor, measuring local deformations. For the piezoelectric actuators a lead-lag network has also been devised to provide better performance. Let { u s } indicate the forces acting on the Shuttle, { u t } the PWM forces on the truss, \\ u d ] the moments applied at the dish center, and { u p } the forces exerted by the piezoelectric actuators; by partitioning the measurements vector accordingly, the decentralized feedback control law can be expressed as (40a) (40b) (40c) (40d) The most common performance indexes used for antennas are the nominal pointing error and the average shape error, whose definitions and limits for a large reflector are pointing error = V { t f c ) ' \\ & c } / 3 <0.02 deg shape error = V (za } ' [ za } /na < 5 mm (41a) (41b) where { d c } represents the three rotations at the center of the antenna, and {za } are the displacements of the na nodes of the dish perpendicular to the dish plane. These performance indexes are nonlinear and difficult to treat numerically, so a more simple linear quadratic function of a performance vector {x) is used to build a suitable quadratic cost function to be minimized 02 (42) (43) The matrices [Qx] and [Qu] are diagonal with unit weighting factors for the first two entries of the performance vector, 10 for the modal coordinates, 1/10 for the Shuttle actuators, 1/1000 for the truss actuators, and 1/10,000 for the piezoelectric actuators. A sampling rate of 2 samplings/s, i.e., 10 times the highest natural frequency considered, was chosen for the controller. Table 3 reports the optimal firing delays for each of the four pairs of thrusters located on the flexible truss. As predicted by Table 3 Actuator firing delay times of the Shuttle antenna system Actuator Delay r F.480 FZ15\\ 0.2497 0.2485 0.2495 0.2496 D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 Table 4 Gain parameters and lead and lag constants of the piezoelectric actuators Actuator Pi P2 P3 P4 PS ?6 Kp -314.4 151.9 -115.2 -219.6 161.5 -309.1 b 0.8095 1.276 0.0185 0.0226 1.125 0.2713 a 0.5396 0.7791 0.0084 0.2780 0.5446 0.3213 Shuttle Attached Antenna 5.00 - Fig. 9 Impulse response of the Shuttle-antenna system. Eq. (17), the optimal delays are quite close to half the sampling period. An analysis of the gain parameters, lead and lag constants of the piezoelectric actuators reported in Table 4, shows a nonsymmetric behavior of the control, in spite of the structural symmetry, due to the unsymmetry of the natural modes representative of the antenna. A mixture of integrating and derivative effects of the lead-lag networks can be seen, and it is remarked that this solution is the best one compatibly with the structure of the system, since the lead and lag constants were included as unknown parameters during the minimization process. The closed-loop response of the system to an impulse comparable to the effect of a lateral docking maneuver, producing a lateral velocity increment of the Shuttle of 1 cm/s in the Y direction, has been simulated considering PAM and PWM control of the truss. In the latter case all of the thrusters are supposed to have a unique thrust level of 10 kg. The time histories reported in Fig. 9 are in good agreement with the performances already discussed. The sampling time and the amplitude of the PWM inputs are well within the hypothesis at the base of the theory presented. No control saturations occur, and once more it is demonstrated that the application of PWM with an optimal delay is perfectly equivalent to PAM control. It is remarked that this system is open-loop neutrally stable, and despite this fact the response of the PWM controlled system shows no tendency to become unstable and no errors in the system displacements or discrete inputs. This holds both for points located near and far from the location of the pulsed thrusters. Just a slight intersample ripple appears in the velocity at the truss corner where the pulsed actuator is located. IV. Conclusions A method for the pulse-width application of a discrete pulse amplitude control law computed for a linear system has been proposed. This conversion technique maintains the dynamic performance of the PAM control and requires a simple equivalence of the total impulse applied during each sampling interval and the computation of the firing time delay. Since the latter depends only on system parameters, it can be computed separately from the control law. This fact is fairly attractive for practical applications in which a PWM control is required, since it allows computation of the control law for a PAM control system, using one of the many available software packages. The only further operation required to perform the conversion from PAM to PWM is one multiplication for each of the inputs and a constant firing delay which, under reasonable assumptions, does not cause unpredictable effects on the system performance. References franklin, G. F., and Powell, J. D., Digital Control of Dynamic Systems, Addison-Wesley, Reading, MA, 1980. 2Sutton, G. P., Rocket Propulsion Elements: An Introduction to the Engineering of Rockets, Wiley, New York, 1986. 3Anthony, T. C., Wie, B., and Carroll, S., \"Pulse Modulated Control Synthesis for a Flexible Spacecraft,\" Proceedings of the AIAA Guidance, Navigation, and Control Conference, AIAA, Washington, DC, 1989, pp. 65-76. 4Kubiak, E. T., Penchuk, A. N., and Hattis, P. D., \"A Frequency Domain Stability Analysis of a Phase Plane Control System,\" Journal of Guidance, Control, and Dynamics, Vol. 8, No. 1, 1985, pp. 50-55. 5Friedland, B., \"Modeling Linear Systems for Pulsewidth-Modulated Control,\" IEEE Transactions on Automatic Control, Vol. AC21, Oct. 1976, pp. 739-746. 6Friedland, B., Control System Design: An Introduction to StateSpace Methods, McGraw-Hill, New York, 1987. 7Bernelli-Zazzera, F., Mantegazza, P., and Ongaro, F., \"A Method to Design Structurally Constrained Discrete Suboptimal Control Laws for Actively Controlled Aircrafts,\" Aerotecnica Missili e Spazio, Vol. 67, No. 1-4, 1988, pp. 18-25. 8Wang, S. J., Lin, Y. H., and Ih, C. H. C., \"Dynamics and Control of a Shuttle Attached Antenna Experiment,\" Journal of Guidance, Control, and Dynamics, Vol. 8, No. 3, 1985, pp. 344-353. 9Quinn, R. D., and Meirovitch, L., \"Maneuver and Vibration Control of SCOLE,\" Journal of Guidance, Control, and Dynamics, Vol. 11, No. 6, 1988, pp. 542-553. 10Bernelli-Zazzera, F., Ercoli-Finzi, A., and Mantegazza, P., \"Mixed Discrete/Pulse-Width Control of a Shuttle Attached Antenna,\" Proceedings of the X Congresso Nazionale AIDAA, ETS Editrice, Pisa, Italy, Oct. 1989, pp. 469-476. D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58"
+ ]
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+ {
+ "image_filename": "designv11_6_0000979_1.2802427-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000979_1.2802427-Figure1-1.png",
+ "caption": "Fig. 1 Diagram of spatiai mechanism for measuring inertia tensor",
+ "texts": [
+ " The first is a small device suitable for measuring of the inertia tensor of small specimens (maximum dimension 250 mm, maximum mass 6 kg). The second is larger (mass range 50 -\u0302 200 kg, maximum length about 2 m). This paper presents the kinematic and dynamic analyses of the spatial mechanism for measuring the inertia tensor, and describes the principle of identification and calibration proce dures. Some examples of inertia tensor identification are then given and discussed. 2 Kinematic Analysis Figure 1 shows the spatial mechanism for measuring the inertia tensor; Fig. 2 is a photograph of the smaller version of the prototype mechanism. A fixed coordinate system XYZ with origin at point O is introduced; axis Z is vertical, whereas axes X and Y lie in the horizontal plane. Plate 7r, which is used to mount the specimen, rotates around fixed point O, where there is a spherical pair. This pair is airlubricated in order to reduce friction torque. Disks Ci and C2 rotate around axes X and Y, respectively, by means of two revolute joints and are named \"adjustment disks"
+ ],
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+ },
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+ "image_filename": "designv11_6_0003394_tmag.1985.1064226-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003394_tmag.1985.1064226-Figure6-1.png",
+ "caption": "Fig. 6. Equipotential plots of the motor",
+ "texts": [
+ " A finite element mesh of 2906 triangular elements of first order and a t o t a l of 1474 nodes to the entire cross section is shown in Fig.5. The sky-line storied technique is taken. There are 29 average elements per line. The rotor currents for slip s with frequence sf, may be modelled by modification of rotor condu.chvity where f , is the su.pply freqwncy. In the rotor, the equation is V V w Fig. 5 . Einite eiement mesh 2291 REFERENCE A = A,sinCswt + rp), so aiiAIht = jwasA = jwcr'A 6' is equivalent conductivity with 6' = sa. The solution has been performed for slip values from 0 to 1. The equipotential plots are shown in Fig.6 at slip s= 1, and computed exciting currents versus the slip in Fig. 7. ' CONCLUSION The matrix method which ombines field equations with circuit equations has been, developed for calculating the performances of electromagnetic devices with specified terminal voltages and external impedances of electric circuit. This approach takes into account eddy current effects and creates a symmetric system with respect to the ones mentioned in the literature. I t has been verified using a 4-pOle shaded-pole motor and a electromagnetic relay in which the exciting current is computed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002571_cca.1996.558742-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002571_cca.1996.558742-Figure2-1.png",
+ "caption": "Figure 2: Rate of strain in a continuum",
+ "texts": [
+ " In addition, F can be written df d X F = - ( x , t ) 1 1 2 2 - -E+-s2 where E is the symmetric part of the deformation and 1(2 its skew-symmetric part. In continuum mechanics, E represents the rate of strain tensor and Jz is the rotation tensor [Aris, 19621. 3.1. Rate of strain tensor Since E is symmetric, it has n real eigenvalues and n orthogonal eigenvectors. The eigenvectors give the stretching directions of the continuum, and the corresponding real eigenvalues give the stretching velocities in these directions. This is illustrated in Figure 2, and motivates the following definition. Definition 1 Given the continuously differentiable system equations k = f(x, t ) , a region of the state space is called strictly contracting (expanding) i f F or E is uniformly negative (positive) definite in that region. Note that by a region we mean an open connected set, and by F uniformly negative definite we mean that 3 ,b > 0, VX, V t 2 0, F(x, t ) 5 -PI < 0 3.2. Rotation tensor The skew-symmetric tensor Cl can be regarded as a generalized crossproduct matrix [Fluegge, 19721, which means that any vector r multiplied with Cl is perpendicular to r"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-13-1.png",
+ "caption": "Figure 1-13. Grating coupler without mechanical parts using a CCD array (according to [77]).",
+ "texts": [
+ " Both input and output couplers are realized depending on whether radiation (incident) is coupled into the waveguide to be guided or leaves the waveguide in the grating region. The principle is shown schematically in Figure 1-12. A variety of set-ups have been developed [20]. Commercially available is a grating coupler system from Artificial Sensing Instruments (ASI) in Zurich, Switzerland. A further development is a set-up with a position sensitive CCD array which avoids mechanical angle scanning to find the optimum coupling angle [80] (see Figure 1-13). Another possibility is the bi-diffractive coupler. In Figure 1-14, the grating structure is shown schematically, representing a mixed grating with two grating constants [162], A second angle of outcoupling is achieved which differs from that of the normal reflection. By these means, the signal-to-noise ratio drastically increases and this set-up is simpler than the ASI instrumentation. 1.2 Principles of Optical Transduction 19 Using embossed polycarbonate gratings, even disposable chips can be considered"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure1-1.png",
+ "caption": "Fig. 1. The deformation of an in\u00aenitesimal element whose undeformed con\u00aeguration is a rectangular parallelepiped.",
+ "texts": [
+ " We also illustrate the use of Jaumann stresses and strains and the new concepts of local displacements and orthogonal virtual rotations [21] in the development of a geometricallyexact theory for shells with arbitrary initial curvatures and show the correlation of energy and vector formulations. Moreover, we illustrate the use of corotated Cauchy stresses and corotated Eulerian strain rates in elastoplastic analysis. To derive the elastic energy of a structure, we consider an in\u00aenitesimal element whose undeformed shape is a cube, as shown in Fig. 1. Here, the frame x1x2x3 is an orthogonal rectilinear inertial frame, the base vectors along the axes x1, x2, and x3 are j1, j2, and j3, respectively. The frame x1x2x3 represents the rigidly translated and rotated con\u00aeguration of the frame x1x2x3, and the base vectors along the axes x1, x2, and x3 are i1, i2 and i3, respectively. Moreover, fk are forces acting on the deformed surfaces and v (=vkjk) denotes the absolute displacement vector of the point O and also the rigid-body translation of the frame x1x2x3",
+ " Engineering stresses smn and engineering strains emn If it is assumed that @v @xm jn @v @xn jm 6 then it follows from Equations (2) and (6) that dP V 0 smndemn dV 0 7 where smn 1 2 f m dxp dxq jn f n dxr dxs jm , m 6 p 6 q, n 6 r 6 s 8 emn 1 2 @v @xm jn @v @xn jm 9 Here smn and emn are called engineering stresses and engineering strains, respectively. Both smn and emn are symmetric. Because of the assumption, Equation (6), Equation (7) is not exact. Second Piola\u00b1Kirchho stresses Smn and Green\u00b1Lagrange strains Lmn Since @rO/@xm=jm in Fig. 1, d(@rO/ @xm jn) = d( jm jn) = 0. Moreover, the position vector ro of the point o is given by ro=rO+v and @ro/ @xm=lmim\u00c3 (no summation), where im\u00c3 denotes the unit vector along the deformed dxm and lm denotes the stretch along im\u00c3 , as shown in Fig. 1. Hence, d @v @xm jn d @ rO @xm jn @v @xm jn d @ ro @xm jn d lmim\u0302 jn 10 Washizu [2] showed that the surface traction force fm can be represented in terms of second Piola\u00b1 Kirchho stresses Smk and stretches lk as f m Sm1l1i1\u0302 Sm2l2i2\u0302 Sm3l3i3\u0302 dxp dxq, p 6 q 6 m 11 Substituting Equations (10) and (11) into Equation (2) yields dP V 0 S11l1i1\u0302 S12l2i2\u0302 S13l3i3\u0302 jnd l1i1\u0302 jn S21l1i1\u0302 S22l2i2\u0302 S23l3i3\u0302 jnd l2i2\u0302 jn S31l1i1\u0302 S32l2i2\u0302 S33l3i3\u0302 jnd l3i3\u0302 jn dx 1 dx 2 dx 3 12 Green\u00b1Lagrange strains (or Lagrangian strains) Lmn are de\u00aened by using the change of the squared length of an in\u00aenitesimal line segment as 2Lmn dxm dxn dro dro \u00ff drO drO @ ro @xm @ro @xn \u00ff @ rO @xm @rO @xn dxm dxn 13 Hence, Lmn 1 2 @ro @xm @ro @xn \u00ff @rO @xm @ rO @xn 1 2 lmim\u0302 lnin\u0302 \u00ff jm jn 1 2 lmim\u0302 lnin\u0302 \u00ff dmn 14 where repeated subindices do not imply summations and dmn denotes the Kronecker delta function. We note that Lmn=Lnm. Using the fact that d(dmn) = 0 and Smn=Snm [2], we obtain S12 l2i2\u0302 jn d l1i1\u0302 jn S21 l1i1\u0302 jn d l2i2\u0302 jn S12d l1i1\u0302 jn l2i2\u0302 jn S12d l1i1\u0302 l2i2\u0302 S12d 2L12 S12dL12 S21dL21 15 Hence, Equation (12) can be rewritten as dP V 0 SijdLij dV 0 16 which shows that Green\u00b1Lagrange strains are work-conjugate to the second Piola\u00b1Kirchho stresses. Jaumann stresses Jmn and Jaumann strains Bmn Since elastic energy is due to relative displacements among material points, it follows from Fig. 1 that the variation of elastic energy can be represented in terms of relative displacements as [3] dP V 0 f 1 in d @u @x 1 dx 1 in f 2 in d @u @x 2 dx 2 in f 3 in d @u @x 3 dx 3 in 17 where u (=0) is the local displacement vector of the point o with respect to the frame x1x2x3, as shown in Fig. 1. Moreover, Pai and Palazotto [3] showed that the rigidly translated and rotated frame x1x2x3 can be located by requiring that @u @xn im @u @xm in 18 Substituting Equation (18) into Equation (17) yields dP V 0 JmndBmn dV 0 19 where Jmn 1 2 J\u0302mn J\u0302nm , J\u0302mn f m dxp dxq in, m 6 p 6 q 20 Bmn 1 2 @u @xm in @u @xn im @u @xn im @u @xm in Bnm 21 Here Jmn are the so-called Jaumann stresses and Bmn are the so-called Jaumann strains. We note that Equation (18) makes Jaumann strain and stress tensors symmetric",
+ " The vector representations of strains shown in Equations (4), (9), (14), (21), (24) and (32) are valid for any orthogonal curvilinear or rectilinear coordinate systems. One can substitute v = vkjk or u= ukik into these equations to obtain strain\u00b1displacement relations. However, for curvilinear coordinate systems, @jk/@xm and @ik/@xm may be nontrivial and results in initial curvature-induced terms. Equations (4), (9) and (24) show that the directions of the displacement gradients, engineering strains and in\u00aenitesimal strains are along the undeformed coordinates, which causes the non-objectivity. Equation (14) and Fig. 1 show that the directions of Green\u00b1Lagrange strains are along the directions of im\u00c3 , which are not three perpendicular directions. Equation (32) and Fig. 2 show that Almansi strains are along the directions of jm\u00c4 , which are not three perpendicular directions. Equation (21) shows that the directions of Jaumann strains are de\u00aened with respect to the deformed coordinates and along three perpendicular directions. Such characteristics are convenient for the imposition of shear stress conditions on the bonding surface in deriving the shear warping functions of beams, plates and shells [23]",
+ " To derive the relationship of di erent stress measures, we consider an undeformed area dA with a unit outward normal N(=Nkjk) and its deformed area da with a unit outward normal n(=nkjk), as shown in Fig. 7(a). Because F= dV/dV0, dV0=dAN dx = dANk dxk, and dV= dan dy= danm dym=danmFmk dxk, we obtain F dANk danmFmk 57 It follows from Equation (3) and Fig. 7(a) that f f 1 f 2 f 3 dAN1j1 s\u03021sj1js dAN2j2 s\u03022sj2js dAN3j3 s\u03023sj3js dANrs\u0302rsjs 58a Second Piola\u00b1Kirchho stresses are measured with respect to the rigidly rotated undeformed area dANkik. Moreover, it follows from Fig. 1 that dx1j1 is deformed into l1 dx1i1\u00c3 and hence l1i1\u00c3 =Fs1js. Consequently, it follows from Equation (11) and Fig. 7(a) that f dAN1i1 S1klki1ik\u0302 dAN2i2 S2klki2ik\u0302 dAN3i3 S3klki3ik\u0302 dANrSrklkik\u0302 dANrSrkFskjs 58b Because Jaumann strains are measured with respect to the rigidly rotated undeformed area dANkik, it follows from Equation (20) and Fig. 7(a) that f dANrir J\u0302rkirik dANrJ\u0302rkik dANrJ\u0302rkTksjs 58c Next we consider the same undeformed and deformed areas as those in Fig. 7(a) but described in terms of Euler coordinates, as shown in Fig"
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+ "image_filename": "designv11_6_0001045_a:1019555013391-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001045_a:1019555013391-Figure4-1.png",
+ "caption": "Figure 4. A system with a 2 dof joint.",
+ "texts": [],
+ "surrounding_texts": [
+ "In [7], recursive combination rules have been found in order to find such a minimal parameter set. Starting from the leaves of the tree-like structure, these rules determine the parameters that combine on a body, those that completely disappear from the equations, and those that are reported on the preceding body, depending on the nature (prismatic or revolute) of the joints. For example, Table I gives the combination rules that are to be applied for a revolute joint j . These rules have been demonstrated in the case of one dof joints. When joints have more than one dof, ROBOTRAN inserts fictitious massless bodies between two real bodies and apply the same rules. However, it can be shown that, for some MBS structures, the previous rules are not sufficient anymore, as shown in the following simple didactic example. EXAMPLE. 2 (orthogonal rotational) dof joint. Starting from body 3, we recursively apply the rules described in [7] and reproduced in the table, to our examplative structure: \u2022 Body 3 identifiable parameters: b3 x , b3 z , K3 xy , K3 xz, K 3 yz, K 3 yy , K3 d = (K3 zz \u2212 K3 xx)/2. \u2022 Body 2 reports from body 3: K\u22172 = K3 s 0 0 0 0 0 0 0 K3 s with K3 s = (K3 zz + K3 xx)/2 b\u22172 = 0 b3 y 0 identifiable parameters: b\u22172 y , K\u22172 zz , K2 d = (K\u22172 xx \u2212 K\u22172 yy )/2. \u2022 Body 1 reports from body 2: K\u22171 = K1 + K2 s 0 0 0 K2 s 0 0 0 0 with K2 s = (K\u22172 xx +K\u22172 yy )/2 b\u22171 = b1 identifiable parameters: b\u22171 x , b\u22171 z , K\u22171 yy . If we examine the identifiable parameters on body 2, we have both K\u22172 zz = K3 s and K2 d = K3 s /2. This means that we end up with two parameters that are multiples of each others, so that only one of them should be kept. In order to detect these particular cases, two solutions are foreseeable: the first one is to try to register analytically all the possible cases where such a situation occurs: this presents the risk to forget some of them. The other solution takes advantage of symbolic manipulations, and is the only effort to cover all possible particular situations of this kind in an efficient way. We will not develop the combination rules here (for a detailed description, see [7]), but briefly expose the methodology we have followed in order to symbolically apply them in ROBOTRAN to any open MBS and to automatically generate its minimal parameterization: 1. All the possible combinations are symbolically performed on the pre-computed barycentric parameters using the above mentioned rules. Since, at each step, we have the symbolic expression of the previously determined identifiable parameters at our disposal, ROBOTRAN can symbolically check that any new parameter to be formed is not a multiple of a previous one. This provides us with all the possible combined parameters that can appear in the dynamical equations, together with their symbolic expression. We will call this set {p}. 2. The inverse dynamics equations are calculated using the recursive Newton\u2013 Euler technique described in Section 2. It must be noted that these equations are written with respect to the barycentric parameters. These do not correspond to parameter set {p} found in step 1. In fact, we can consider that {p} is forming a new set of barycentric parameters that is constructed from the real barycentric parameters in the following way: some of the barycentric parameters are themselves present in {p}: they remain unchanged; barycentric parameters that do not appear at all in {p} are removed; the remaining parameters of {p} can be introduced as components of the barycentric parameters according to some indications derived from the recursive combination rules of [7]. These indications are briefly explained in Appendix A. 3. These equations are then symbolically derived with respect to {p} using a recursive derivation routine developed within ROBOTRAN [10]. When computing the inverse dynamics of the MBS (Section 2), each recursive equation is assumed to depend, explicitly or not, on each variable of the set {p}. This a priori dependency provokes the systematic creation of a recursive auxiliary variable, being a partial derivative of the current equation, even if in the end it appears that the latter variable was useless: indeed, at the end of the recursion, an elimination process will detect it and remove the corresponding equation before printing. In this way, we obtain a matrix D with Dij = \u2202\u03c4 i/\u2202pj . 4. D may contain some columns that are identically equal to zero. These columns correspond to the parameters that do not appear in the equations. These parameters are removed from {p} and we finally end up with the minimal parameterization of the MBS."
+ ]
+ },
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+ "image_filename": "designv11_6_0001635_3.20858-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001635_3.20858-Figure6-1.png",
+ "caption": "Fig. 6 Topology of the Shuttle-attached antenna.",
+ "texts": [],
+ "surrounding_texts": [
+ "To validate the theory, two different control designs are presented, i.e., a spring-mass-damper system and a shape and pointing control system for a space antenna. The active controller has been determined in both cases by means of a discrete linear suboptimal control technique,7 and the system response has then been evaluated via an exact nonlinear integration of the equations of motion, to take into account the presence of saturations and PWM actuators. Pulse-width modulated actuators are always assumed to be coupled and acting in opposite directions, the switching between the two being determined by the sign of the firing duration time 6. Example 1: Second-Order System The first test was carried out to demonstrate the effects of the firing delay r, the maximum input amplitude UM, and the D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 sampling time A on the transient and steady-state response of a system subjected to a control input and to a reference command by using the spring-mass-damper system shown in Fig. 2. The dynamics of the system having mass m, damping coefficient c, and elastic spring constant k is represented in the state-space form by *l r-2f\u00ab *H i -o>2 0 the input force (/) is given by (34) (35) where [r] is the desired set point. It can be noted that the feed-forward control, i.e., mu2[r], is capable of achieving the desired set point in case of perfect model knowledge. Thus the feedback terms are added to improve response performances and to take into account uncertainties in the model knowledge. The system parameters are m = 1, f = 0.1, and co = 6.28, i.e., an open-loop natural frequency of 1 Hz. With these system characteristics, a controller sampling time of 0.1 s appears appropriate. Specifications for the closed-loop system are established in terms of damping factor, to be as close as possible to 0.7, and a sufficiently low input requirement to prevent undesirable control saturations in PWM operational mode. To meet the dynamic performances, kv and ke are computed for a PAM control by minimizing the discrete quadratic performance index7: (36) c f Fig. 2 Second-order system. Spring-Mass-Damper System Sampling time 0.1 sec ; no input delay Sampling time 0.1 sec ; optimal input delay 0.0 0.0 0.0 1.0 2.0 3.0 0.0 1.0 2.0 3.0 Time (sec) Time (sec) Sampling time 0.05 sec ; no input delay Sampling time 0.05 sec ; optimal input delay 1.5 -| 1.0 2.0 3.0 0.0 1.0 2.0 3.0 Time (sec) Time (sec) \u2014\u2014PAM -o-4Jmax = 50 \u2014x-Umox = 200 Fig. 3 Displacement response of second-order system (PAM and PWM). where E {\u2022} indicates the expected value operator for a suitable set of stochastic disturbances and/or nonzero initial conditions, and [Qy] = (37a) (37b) (37c) which leads to kv = -2.67, ke = 24.2. Two different sampling times were then used to analyze the system response, namely A = 0.1 and 0.05 s. Shorter sampling times are not considered since this would mean operating almost as in continuous time, so that PWM control would not be applicable. The optimal firing delay T and the closed-loop eigenvalues are collected in Table 1, whereas the step responses to a unit reference command, either PAM or PWM, with different delays and maximum amplitudes, are reported in Figs. 3-5. In Fig. 5 the PAM input is plotted vs the left ordinate axis, whereas PWM inputs, i.e., duration, are plotted vs the right ordinate axis. Considering Table 1, it should be immediately remarked that, depending on A, the system eigenvalues are not constant. This is not surprising since, because of Eq. (30), both the state transition matrix [$] and input matrix [F] depend on A, whereas in this particular case [K] and [C] are held constant. For the purpose of the present example, this is not important, since the comparisons are done between PAM and PWM responses of analogous systems, with the sampling period as the distinctive parameter of the system configuration. D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 The analysis of the step responses is in good agreement with the theoretical analysis. A few considerations should be noted. As stated in Eq. (8), if the delay is not optimal, the error of the PWM controlled response relative to the \"desired\" response, i.e., the PAM controlled response, is proportional to the input amplitude UM, and this clearly appears from the steady-state biases in Figs. 3 and 4. Moreover, in this particular example, the value UM = 50 is quite close to the steady-state discrete input, which is precisely 39.48. Then it is obvious that the steady-state value of 5 will be quite close to A. This does not agree with the assumptions made to establish the relationship between PAM and PWM control and explains why the performances of the system subjected to a PAM input and to a PWM input with null delay are quite similar. In fact, from Eq. (4), it is seen that, for d = A, the equivalence between PAM and PWM control is obtained with r = 0. Figures 3 and 4 clearly point out the peculiar response of PWM controlled systems. Even at \"steady state,\" the system tends to oscillate around the average condition, due to the on/off input type, and the only reduction in amplitude is due to the integral action of the system dynamics. From Fig. 5 it can be seen that the PWM is always of the same sign. Thus the limit cycles are due only to the elastic action of the system and not to a change of sign of the control force. This fact also explains why the limit cycle amplitude is larger for the higher input level. In fact, since the pulse intensity is equivalent, the duration is shorter for the higher input, and thus it leaves more time for the elastic action to operate, causing a larger amplitude oscillation. The optimum firing delay r guarantees that the steady-state response of the PAM and PWM controlled systems are the same. The difference in the transient response depends on the input amplitude. Higher amplitudes mean smaller pulse firing durations 6, and so the approximation of Eq. (6) becomes indeed true, and Eq. (7) represents the real dynamic behavior of the system, so that the optimal firing delay effectively minimizes the response error. The same holds also for smaller sampling periods since, as shown by Eq. (5), d is also proportional to A. Considering that in discrete control the sampling time is usually limited by the control hardware and cannot therefore be made as small as possible, it can then be stated that it is advisable to select the optimal firing delay for PWM control and, compatible with actuator limits, operate with a sufficiently high input level. Example 2: Shuttle-Attached Antenna The second example shows an application of a mixed PAM/ PWM control to the shape and pointing control of a large space antenna. This system is clearly more complex than the preceding one, and since the antenna structural damping is neglected and the overall system is a free body, it is open-loop neutrally stable. Nevertheless, it will be shown that the equivalent PWM control can be successfully applied also to this kind of system. The antenna studied in the present work consists of a large dish connected to the Shuttle by an aluminum L-shaped flexible truss.8 Figures 6-8 depict the topology and dimensions of the antenna, along with its finite element representation consisting of 95 grid points. Three representative points are marked in Fig. 7, and their dynamic behavior will be used to assess the performance of the system, i.e., node 480 at the corner of the flexible truss, node 751 at the center of the dish, and node 920 on the dish boundary. The flexible truss is considered to be clamped to the Shuttle. All of the elements are supposed to be uniform tubular beams with a cross-sectional area of 200 mm2, Young's modulus equal to 72,520 D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 N/mm2, and density 3000 kg/mm3. The total mass of the antenna is 635 kg, and the total system mass is 102,788 kg. The system dynamics are governed by two sets of equations, one governing the average rigid body motion and another governing the small perturbations of the rigid motion and the elastic deformations. A detailed derivation of the equations of motion is found in the literature9'10 and will not be repeated here for the sake of conciseness. Instead, attention is focused on the small perturbed overall motion and on the elastic deformations as represented by the simplified system (38) in which only two coupling terms [A] and [\u00a3] are present. In Eq. (38), [V] is the matrix of the antenna branch modes, i.e., the modes of the antenna clamped to the still standing Shuttle; [70] and [m] are the inertia and mass matrices of the system in the undeformed condition; {/?) , {/3) , and {q} are, respectively, the perturbed displacement and orientation of the system center of gravity and the antenna branch modal coordinates. It is possible to reformulate Eq. (38) as a set of first-order linear differential equations, with state vector [ x ] , state matrix [A], input vector [u ) , and input matrix [B] given by (39a) V'QiV (39b) 0 J 0 0 0 0 0 0 0 0 X2 lx] + [Rift #i 0 q\\ To -MI A ] = [ Vf ] = m 0 F'A ' 0 Io V'T, 0 r > 1\u0302 J J AF E 'V I { u } = [F, (39d) The branch mode shapes corresponding to the lowest 10 eigenfrequencies were used to represent the antenna. This restricted choice of natural mode shapes is considered accurate enough since, as illustrated in Table 2, they are representative of a wide class of possible motions of the antenna. The analysis of the eigenvalues of the [A] matrix of Eq. (39), also reported in Table 2, shows that basically the coupling has the effect of modifying the flexible branch modes that nonetheless are enough to correctly represent the lowest vibration modes of the whole system since, due to the massive Shuttle, the last branch modes are practically the vibration modes. The control system consists of 23 actuators driven in a decentralized way from collocated sensors. Six of them exert forces and moments on all six degrees of freedom of the rigid Shuttle; eight thrusters are placed on the flexible truss: four on the truss corner acting in the X and Y directions and four at the end acting in the Y and Z directions. The corresponding sensors are local displacement and velocity sensors. The control of the dish is carried out by using three reaction wheels, acting along the three axes at the connection with the truss, driven by angle and angular rate sensors and by six piezoelectric layers on the dish's outer radial beams, marked in Fig. 7 as Pi-P6- The piezoelectric layers are supposed to work in couples, one acting as an actuator and one as a sensor, measuring local deformations. For the piezoelectric actuators a lead-lag network has also been devised to provide better performance. Let { u s } indicate the forces acting on the Shuttle, { u t } the PWM forces on the truss, \\ u d ] the moments applied at the dish center, and { u p } the forces exerted by the piezoelectric actuators; by partitioning the measurements vector accordingly, the decentralized feedback control law can be expressed as (40a) (40b) (40c) (40d) The most common performance indexes used for antennas are the nominal pointing error and the average shape error, whose definitions and limits for a large reflector are pointing error = V { t f c ) ' \\ & c } / 3 <0.02 deg shape error = V (za } ' [ za } /na < 5 mm (41a) (41b) where { d c } represents the three rotations at the center of the antenna, and {za } are the displacements of the na nodes of the dish perpendicular to the dish plane. These performance indexes are nonlinear and difficult to treat numerically, so a more simple linear quadratic function of a performance vector {x) is used to build a suitable quadratic cost function to be minimized 02 (42) (43) The matrices [Qx] and [Qu] are diagonal with unit weighting factors for the first two entries of the performance vector, 10 for the modal coordinates, 1/10 for the Shuttle actuators, 1/1000 for the truss actuators, and 1/10,000 for the piezoelectric actuators. A sampling rate of 2 samplings/s, i.e., 10 times the highest natural frequency considered, was chosen for the controller. Table 3 reports the optimal firing delays for each of the four pairs of thrusters located on the flexible truss. As predicted by Table 3 Actuator firing delay times of the Shuttle antenna system Actuator Delay r F.480 FZ15\\ 0.2497 0.2485 0.2495 0.2496 D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58 Table 4 Gain parameters and lead and lag constants of the piezoelectric actuators Actuator Pi P2 P3 P4 PS ?6 Kp -314.4 151.9 -115.2 -219.6 161.5 -309.1 b 0.8095 1.276 0.0185 0.0226 1.125 0.2713 a 0.5396 0.7791 0.0084 0.2780 0.5446 0.3213 Shuttle Attached Antenna 5.00 - Fig. 9 Impulse response of the Shuttle-antenna system. Eq. (17), the optimal delays are quite close to half the sampling period. An analysis of the gain parameters, lead and lag constants of the piezoelectric actuators reported in Table 4, shows a nonsymmetric behavior of the control, in spite of the structural symmetry, due to the unsymmetry of the natural modes representative of the antenna. A mixture of integrating and derivative effects of the lead-lag networks can be seen, and it is remarked that this solution is the best one compatibly with the structure of the system, since the lead and lag constants were included as unknown parameters during the minimization process. The closed-loop response of the system to an impulse comparable to the effect of a lateral docking maneuver, producing a lateral velocity increment of the Shuttle of 1 cm/s in the Y direction, has been simulated considering PAM and PWM control of the truss. In the latter case all of the thrusters are supposed to have a unique thrust level of 10 kg. The time histories reported in Fig. 9 are in good agreement with the performances already discussed. The sampling time and the amplitude of the PWM inputs are well within the hypothesis at the base of the theory presented. No control saturations occur, and once more it is demonstrated that the application of PWM with an optimal delay is perfectly equivalent to PAM control. It is remarked that this system is open-loop neutrally stable, and despite this fact the response of the PWM controlled system shows no tendency to become unstable and no errors in the system displacements or discrete inputs. This holds both for points located near and far from the location of the pulsed thrusters. Just a slight intersample ripple appears in the velocity at the truss corner where the pulsed actuator is located. IV. Conclusions A method for the pulse-width application of a discrete pulse amplitude control law computed for a linear system has been proposed. This conversion technique maintains the dynamic performance of the PAM control and requires a simple equivalence of the total impulse applied during each sampling interval and the computation of the firing time delay. Since the latter depends only on system parameters, it can be computed separately from the control law. This fact is fairly attractive for practical applications in which a PWM control is required, since it allows computation of the control law for a PAM control system, using one of the many available software packages. The only further operation required to perform the conversion from PAM to PWM is one multiplication for each of the inputs and a constant firing delay which, under reasonable assumptions, does not cause unpredictable effects on the system performance. References franklin, G. F., and Powell, J. D., Digital Control of Dynamic Systems, Addison-Wesley, Reading, MA, 1980. 2Sutton, G. P., Rocket Propulsion Elements: An Introduction to the Engineering of Rockets, Wiley, New York, 1986. 3Anthony, T. C., Wie, B., and Carroll, S., \"Pulse Modulated Control Synthesis for a Flexible Spacecraft,\" Proceedings of the AIAA Guidance, Navigation, and Control Conference, AIAA, Washington, DC, 1989, pp. 65-76. 4Kubiak, E. T., Penchuk, A. N., and Hattis, P. D., \"A Frequency Domain Stability Analysis of a Phase Plane Control System,\" Journal of Guidance, Control, and Dynamics, Vol. 8, No. 1, 1985, pp. 50-55. 5Friedland, B., \"Modeling Linear Systems for Pulsewidth-Modulated Control,\" IEEE Transactions on Automatic Control, Vol. AC21, Oct. 1976, pp. 739-746. 6Friedland, B., Control System Design: An Introduction to StateSpace Methods, McGraw-Hill, New York, 1987. 7Bernelli-Zazzera, F., Mantegazza, P., and Ongaro, F., \"A Method to Design Structurally Constrained Discrete Suboptimal Control Laws for Actively Controlled Aircrafts,\" Aerotecnica Missili e Spazio, Vol. 67, No. 1-4, 1988, pp. 18-25. 8Wang, S. J., Lin, Y. H., and Ih, C. H. C., \"Dynamics and Control of a Shuttle Attached Antenna Experiment,\" Journal of Guidance, Control, and Dynamics, Vol. 8, No. 3, 1985, pp. 344-353. 9Quinn, R. D., and Meirovitch, L., \"Maneuver and Vibration Control of SCOLE,\" Journal of Guidance, Control, and Dynamics, Vol. 11, No. 6, 1988, pp. 542-553. 10Bernelli-Zazzera, F., Ercoli-Finzi, A., and Mantegazza, P., \"Mixed Discrete/Pulse-Width Control of a Shuttle Attached Antenna,\" Proceedings of the X Congresso Nazionale AIDAA, ETS Editrice, Pisa, Italy, Oct. 1989, pp. 469-476. D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 08 58"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure8-1.png",
+ "caption": "Figure 8. Factors of the system with form III symmetry and its factors: (a) E; and (b) D.",
+ "texts": [
+ " Consider the determinant of matrix E as det(E) = \u2223\u2223\u2223\u2223\u2223 A + B P 2Pt R \u2223\u2223\u2223\u2223\u2223 From matrix algebra, if a row or column of this matrix is multiplied or divided by a scalar, the amount of the determinant will, respectively, be multiplied or divided by that scalar. Therefore, the second column of the matrix is multiplied by \u221a 2, leading to \u221a 2\u00d7 det(E) = \u2223\u2223\u2223\u2223\u2223 A + B \u221a 2\u00d7P 2Pt \u221a 2\u00d7R \u2223\u2223\u2223\u2223\u2223 2nd row\u00d7 \u221a 2 2\u2212\u2212\u2212\u2212\u2212\u2212\u2212\u2212\u2212\u2192 \u221a 2 2 \u00d7 \u221a 2 det(E) = det(E)= \u2223\u2223\u2223\u2223\u2223\u2223\u2223 A + B \u221a 2P \u221a 2 2 \u00d7 2Pt \u221a 2 2 \u00d7 \u221a 2R \u2223\u2223\u2223\u2223\u2223\u2223\u2223 = \u2223\u2223\u2223\u2223\u2223 A + B \u221a 2P \u221a 2Pt R \u2223\u2223\u2223\u2223\u2223 = det(L(2)) This shows that the determinants of the matrices L(2) and E are identical, and both matrices contain the same sets of eigenvalues. Figure 8 shows the factors of previous problem. A directed edge from i to j , represents a directed spring in the dynamic system. The main characteristic of such a spring is that the connection of this spring to masses is such that it does not take part in the stiffness of k j,i , but it affects ki, j [11]. As it was shown in Sections 3.1 and 3.2, the problems with two and three DOFs can be decoupled into two smaller problems; in the first example, each subproblem had one DOF, and in the second one, one- and two-dimensional subproblems were obtained"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0002457_1.1536652-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002457_1.1536652-Figure1-1.png",
+ "caption": "FIG. 1. Experimental setup for one-step laser cladding by 6 kW high power diode laser: ~1! diode laser head; ~2! optical tube, focusing lens and protection glass; ~3! alignment system for powder nozzle; ~4! cyclone; and ~5! flat powder stream nozzle.",
+ "texts": [
+ " In the cyclone carrier gas and powder particles were separated whereupon powder particles fell gravitationally to the flat nozzle, where the powder stream was spread to a width of the larger dimension of the beam spot. The flat nozzle was positioned at an angle of 60\u00b0 to the work piece. The shielding gas ~Ar! shrouded the powder stream, protecting the hot powder particles from oxidation. Shroud gas also produced a relatively low divergence powder stream, which made it easier to focus the powder stream to a more or less line shape beam spot size. The tip of the flat nozzle was located 30 mm from the work piece. The experimental setup for one-step HPDL cladding is shown in Fig. 1. Machined rectangular sheets of unalloyed low carbon steel Fe52 with dimensions of 100 mm3100 mm and a thickness of 20 mm were used as substrate material. A nickel-based superalloy Inconel 625, which contains chromium and molybdenum as the main alloying elements, was selected as the coating material. The nominal composition of the Inconel 625 powder is 64.1 Ni, 21.5 Cr, 8.9 Mo, 3.8 Nb, 1.2 Fe, and 0.5 Si in wt %. The particle size of the powder was 53\u2013150 mm. The coating samples were prepared by moving the HPDL and powder feeding head fixed to a robot upon substrate materials"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003052_1.2121752-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003052_1.2121752-Figure1-1.png",
+ "caption": "Fig. 1. Geometry of a falling pencil. The bottom end of the pencil is free to slide forward or backward on the table.",
+ "texts": [
+ "3 Given that the center of mass pivots about one foot on the ground, a walking stride will change to a running stride when 2 /R g, where R is the height of the center of mass. For most adults, R is about 1 m so the maximum adult walking speed is about 3.1 ms\u22121. In this paper we consider only the case of a falling pencil because a pencil or pen will be within easy reach of all readers. However, the word \u201cpencil\u201d can be taken as a generic term for any elongated object, including a top-heavy human leg. The geometry is shown in Fig. 1 and the equations of motion are 26 Am. J. Phys. 74 1 , January 2006 http://aapt.org/ajp Downloaded 29 Sep 2012 to 136.159.235.223. Redistribution subject to AAPT F = Md x/dt 1a N \u2212 Mg = Md y/dt 1b and Icmd /dt = NH sin \u2212 FH cos , 2 where M is the pencil mass, x and y are the velocity components of the center of mass, H is the distance from the center of mass to the bottom end of the pencil, Icm is the moment of inertia about an axis through the center of mass, and =d /dt. We will focus our attention on the relatively simple case where x, y, and are all zero and where = 0 at t=0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003512_j.mechatronics.2005.12.002-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003512_j.mechatronics.2005.12.002-Figure5-1.png",
+ "caption": "Fig. 5. Experimental setup.",
+ "texts": [
+ "1 Hz frequency. The physical linear motor application was driven such a way that the proposed velocity controller was implemented in Simulink to gain the desired force reference. The derived algorithm was transferred to C code for dSPACE \u2019s digital signal processor (DSP) to use in real-time. The force command, F*, was fed into the drive of the linear motor using a DS1103 I/O card. The computational time step for the velocity controller was 0.1 ms, while the current controller cycle was 31.25 ls. Fig. 5 shows a diagram of the real-time system. For the Kalman filter, introduced in the previous chapter, a linear state-space model of the mechanical system is derived. The friction and other nonlinearities are assumed to be system noise, which the Kalman filter handles as a random process. The estimated states of the system are velocity of the motor vM, velocity of the load vL, and spring force Fs, i.e. the state vector is x \u00bc x1 x2 x3 2 64 3 75 \u00bc vM vL F s 2 64 3 75. \u00f056\u00de le of PMLSM. The state matrix A, input matrix B and output matrix C in Eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003901_1.2159040-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003901_1.2159040-Figure1-1.png",
+ "caption": "Fig. 1 \u201ea\u2026 Schematic of a rotating ring on multiple ro",
+ "texts": [
+ " Assuming the spring stiffnesses to be small compared to the ring bending stiffness, the method of multiple scales is used to identify parametric instability conditions for different configurations. The significance of stiffening effects due to ring rotation and the occurrence or suppression of instabilities due to symmetry in spring placement are investigated. These analytical results are applied to investigate ring gear instabilities using example planetary gears with nonrotating and rotating ring gears. 2 Problem Formulation Figure 1 a shows a thin ring of uniform cross-section with mean radius r and center O subject to forces at its centroidal surface from M multiple spring-sets, j=1,2 , . . . ,M. Each springset consists of two springs of time-varying stiffness k1j t and k2j t oriented in mutually perpendicular directions with arbitrary orientation angle j 0 j /2 and arbitrary angular coordinate j 0 j 2 measured from fixed E1 at initial time t=0. All angles are measured positive counterclockwise. The springsets and ring rotate at constant angular speed sp and r, respectively",
+ " As the spring-sets rotate, the orientation angles j and relative angular spacing j \u2212 j\u22121 between adjacent spring-sets remain fixed. All spring stiffnesses vary independently with the same period Tm=2 / m, so that each stiffness function is expressed as the Fourier series APRIL 2006, Vol. 128 / 23106 by ASME 16 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F k1j t = k1j 0 + l=1 k1j l eil mt + k\u03041j l e\u2212il mt 1 k2j t = k2j 0 + l=1 k2j l eil mt + k\u03042j l e\u2212il mt Referring to Fig. 1 b , is the angular coordinate of any point on the ring in the inertial E1-E2 reference frame. Similarly, and are the angular coordinates of the same point in the ring-fixed e1 -e2 and spring-fixed e\u03021-e\u03022 reference frames, respectively. The angular coordinates of a material point on the ring are related by = + rt= + spt. The equations of motion are derived in the ring-fixed reference frame. Defining u\u0302 and w\u0302 as the tangential and radial displacements of the centroidal axis of the ring, the coupled equations of motion are 23 rA u\u0308\u0302 + 2 rw\u0307\u0302 \u2212 EA r u\u0302 + w\u0302 \u2212 EI r3 u\u0302 \u2212 w\u0302IV \u2212 rA r 2 u\u0302 + 2w\u0302 + j=1 M \u2212 relt \u2212 j k1j t u\u0302 cos2 j + k2j t u\u0302 sin2 j + k2j t \u2212 k1j t w\u0302 cos j sin j = 0 2 rA w\u0308\u0302 \u2212 2 ru\u0307\u0302 + EA r u\u0302 + w\u0302 \u2212 EI r3 u\u0302 \u2212 w\u0302IV + rA r 2 2u\u0302 \u2212 w\u0302 + j=1 M \u2212 relt \u2212 j k1j t w\u0302 cos2 j + k2j t w\u0302 sin2 j + k2j t \u2212 k1j t u\u0302 cos j sin j = 0 3 where E is Young\u2019s modulus, is density, and I is the area moment of inertia of the cross section"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001080_s0006-3495(93)81454-1-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001080_s0006-3495(93)81454-1-FigureI-1.png",
+ "caption": "FIGURE I (a) Relationship between the torque (MM) generated by the flagellar motor of a tethered cell and the viscous drag (f E) from the medium, when rotation is driven by an electrical field torque MEP + MEO. See the text for details. (b) Schematic illustration of a tethered cell which is rotated by an electric field at WE as described in Principle.",
+ "texts": [],
+ "surrounding_texts": [
+ "INTRODUCTION E. coli has several helical flagella around its cell surface and possesses an ability to swim in aqueous medium by rotating its helical flagellar filaments as propellers. Each flagellum is rotated by a molecular rotary motor anchored in the cytoplasmic membrane (Silverman and Simon, 1974; Berg, 1974). The basal body ofa flagellum embedded in the membrane is thought to serve as a rotor ofthe motor complex, and the stator elements and other structural components are placed around the basal body in the membrane (for recent reviews, see Blair, 1990; Jones and Aizawa, 1991) . The energy source for these motors was found to be the electrochemical potential gradient of a specific ion across the membrane; this gradient is composed of the membrane electrical potential and the chemical gradient of the ion (Manson et al., 1977; Matsuura et al., 1977; Hirota and Imae, 1983). To understand the mechanism ofenergy transduction of the flagellar motor, one of the most effective methods is to investigate the mechanical properties of the motor itself. Specifically, the relationship between torque and rotation rate is a characteristic property of the motor itself, which is closely related to its mechanism. Manson et al. (1980) estimated torque at low speeds (about 10 Hz) in tethered cells of Streptococcus. Lowe et al. (1987) made measurements of torque at various bundle frequencies in swimming cells. Their results showed that in the case of swimming cells the torque of the motor linearly decreased with rotation rate from -50 Hz up to 100 Hz and that values oftorque ofswimming cells were smaller than those of tethered cells.\nIn this study we attempted to measure the relationship between rate ofrotation and torque ofthe flagellar motor\nAddress correspondence to Dr. Yasuo Imae, Department of Molecular Biology, School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan 464-01.\nin tethered cells ofa smooth-swimming E. coli strain and determined the torque over the range 0-55 Hz speed by externally applying a rotating electric field to the cell. By this method, we were also able to extend the measurement to negative rotation (i.e., rotation in the reverse of the natural direction) up to about -20 Hz. Our measurements suggest that the torque of the flagellar motor decreases linearly with the rotation rate within the range observed. We also investigated the temperature effect on the torque versus rotation rate.\nPRINCIPLE\nThe torqueMM generated by the motor ofa tethered cell rotating at angular velocity wo is balanced by the hydrodynamic viscous drag acting on the cell body (Fig. 1 a). The viscous drag may be expressed asfc where f and w are the frictional coefficient of the rotation of the cell about the axis through the tethering position and the angular velocity of the tethered cell, respectively. Under an electric field, free cells migrate along the electric field by two mechanisms. One is the electrophoretic effect because the cells are carrying net charge. The other is a hydrodynamic effect due to the flow of medium driven by electroosmosis, which inevitably exists in a usual cell for the measurement ofthe electrophoresis (Bier, 1959). In contrast, when the same cells are tethered eccentrically on a slide glass by one oftheir flagella, the cells cannot migrate, but show a directional change around a tethered point by the force produced by the electrophoresis and electroosmosis.\nLet us now apply an electric field rotating with an angular velocity WEto an eccentrically tethered cell rotating with wO (#WE). Fig. 1 b illustrates a tethered cell rotating in the presence of an electric field at WE higher than its natural speed (wo < WE). Provided the electric field is sufficiently intense, the cell would be expected to rotate\nBiophys. J. Biophysical Society Volume 64 March 1993 925-933\n0006-3495/93/03/925/09 $2.000006-3495/93/03/925/09 925",
+ "MEO = g(r X (), (2)\nor in terms of scalars by\nMEO = grvo sin X, (vo = 11 v 11 ) (2')\nWAO WE\nMEO\nwhere g represents a geometrical factor including the size of the cell body. Thus, the torque MM, MEP, MEO, and the hydrodynamic viscous drag on the cell bodyfwE are related by the following equation.\nMM + MEP + MEO = f)E, (3) 1- where WE is the axial vector ofthe angular velocity ofthe\nrotating electric field. The electroosmosis is proportional W to the electric field applied as described in Materials and\nMethods and v may be put as\nv = aE. (4)\nEq. 3 equally applies to the cases ofdecreased speed (O < WE < WO) and reverse rotation (WE < 0).\nLet us now gradually decrease the amplitude of the rotating electric field EO without altering the rate WE. The angle X will correspondingly increase toward 900 in compensation for the decline ofthe electric field in order to supply a constant torque, and the tethered cell will continue to rotate at the same angular velocity WE as the electric field. When X just exceeds 90\u00b0, the synchronization is broken and rotation ofthe cell returns to its natural angular velocity w0. From Eqs. 1', 2', 3, and 4 we get the equation\nwith WE, in which X, the angle between the direction of the electric field and the long axis ofthe cell remains less than 90. The torque exerted on the cell body by the electropho-\nresis is given in terms of vectors by\nMEp=q(rXE),(1\nor in terms of scalars by\nMEP = qrEO sin X, (EO = IIEII) ( 1)\nwhere E is the rotating electric field, r is the distance from the tethering axis to the center ofthe cell body and q is the effective charge on the cell. In addition, a torque MEO is exerted on the same cell body by the electroosmotic flow. Let us denote the velocity of the flow as v, the direction of which may be parallel to the electric field. Then, the torque may be expressed in terms ofvectors by\nMM =fwE - (q + ga)rE9, (5)\nwhere El is the threshold amplitude ofthe rotating electric field at the moment of desynchronization. According to Eq. 5, the torque ofthe flagellar motor at WEcan be estimated from El'and factorsf, q, g, r, and a. However, ifwe use a constant-voltage mode for applying the electric field, the real values ofEO are difficult to estimate on account of the polarization at the boundary between the electrodes and the sample solution. Instead, we use the constant-current mode. Let us denote IO as the current that passes through the sample to establish EO in the medium. Then, the relation between EOand IO is written as follows:\nEo= kIo/a, (6)\nwhere k is a geometrical factor ofthe electrode cell and a\nis the specific conductance ofthe sample medium. Then, substituting Eq. 6 into Eq. 5 yields\nMM =fwE - (k/lo)(q + ga)rI9. (7)\nThus, torque ofthe motor is represented as a linear function of both angular velocity WE and the threshold current PO. When the relationship between JO\u00b0 and WE has been obtained experimentally, the torque ofthe mo-\n926 Biophysical Journal Volume 64 March 1993\nTorqu e\n(b)\n(a)\nBiophysical Journal Volume 64 March 1993",
+ "torMM can be expressed as a function of WE using Eq. 7, if the factors, f, k, q, g, r, a, and a are known.\nMATERIALS AND METHODS\nSample preparation A smooth-swimming Escherichia coli strain RP4979 (Ache Y), whose flagellar rotation is fixed in the counterclockwise direction, was used in this study. Cells were grown to early or late logarithmic phase at 300C with shaking in 1% tryptone (Difco Laboratories, Detroit, Michigan), 0.5% NaCl, and 0.5% glycerol (wt/vol). The cells grown in early log phase were used for observation ofreverse (clockwise) rotation oftethered cells by the application of an electric field rotating in the reverse direction, because these large cells were found to be more suitable for such observations. They were harvested by centrifugation at 8,000g for 5 min at room temperature and washed with motility medium containing 5 mM potassium phosphate buffer (pH 7), 0.1 mM EDTA, and 0.5% glycerol, and stored on ice until use.\nThe viscosity of the medium was changed by addition of Ficoll 400 (Pharmacia LKB, Uppsala, Sweden) into sample medium (Manson et al., 1980). A 10% wt/vol stock solution of Ficoll 400 was prepared in motility medium. Solutions of lower Ficoll concentrations were made by dilution. Viscosity was measured in Ostwald and Ubbelohde viscometers at 25.0\u00b0C. For exchange ofthe motility medium, we used a modified version of the flow chamber described by Berg and Block ( 1984). A 3-8 min operation of a peristaltic pump type P-I (Pharmacia Fine Chemicals, Sweden) set at a flow rate of 100-250 ml/h was sufficient for complete exchange of the content of the flow chamber. For preparation of tethered cells, cells were sheared by passage through a Pasteur pipet (7095-5X, Coming Inc., New York) about 200 times per 1 ml medium and attached with antiflagellin antibody to an electrode cell (see below) or the bottom window of the flow chamber. Then a cover glass stored in ethanol before use was wiped with tissue and put onto the electrode cell, or the upper window of the flow chamber cleaned with ethanol and screwed into the flow chamber. These cells were allowed to incubate at room temperature for about 1 h before observation.\nMeasurement system The rotation ofthe tethered bacterial cells was detected by an apparatus schematically shown in Fig. 2. The sample was illuminated in darkfield mode of a microscope (Nikon Co. model L equipped with 20x objective and 15X eyepiece, Tokyo, Japan) with Xenon lamp (UXL300D, Ushio Electric Inc., Osaka, Japan). An image of the cell was focused on a linear graded filter, so that the rotation of the cell was monitored as a light signal, whose intensity was sinusoidally modulated (Kobayasi et al., 1977). The light was detected by a photomultiplier in photon counting mode with a discriminator (R649 and C 1050, Hamamatsu Photonics K.K., Hamamatsu, Japan). The output ofthe discriminator per unit time was counted by a photon counter. Finally, these data were displayed on a personal computer (Apple II plus; Apple Computer Inc., Cupertino, California) and written on a dot printer (SP-500; Seiko Epson Co., Suwa, Japan). The rotation rates of the tethered cells were calculated from the time interval required for an integral number of cycles of the rotation. The size and shape ofthe cell body and the tethering position in the cell were measured by the same microscope in phase-contrast mode at the end of each measurement. For swimming speed measurement, unsheared bacteria diluted to a suitable concentration for observation were placed in the flow chamber and observed in dark-field mode. Swimming speed was measured by analyzing the lengths of the track ofthe cells in the photographs (Imae et al., 1986). To change the temperature of the medium, we placed the flow chamber filled with the sample medium on a temperature-regulated microscope stage controlled by circulation of water from a water-bath\nequipped with a thermostat. The temperature ofthe medium was measured by attaching a chromel-constantan thermocouple (0.1 mm diam.) to the frame ofthe flow chamber. For the calculation oftorque, the temperature dependence of the viscosity of the medium was taken into account. The electrode cell for applying a rotating electric field to tethered cells was made of a slide glass (inset of Fig. 2). Two pairs of pieces of thin platinum foil were attached around a shallow circular well (4 mm diam., 0.2 mm depth) made of epoxy resin on the glass. Sinusoidal current pulses Io(t) cos wEt and Io(t) sin wEt were then supplied to these two pairs ofelectrodes, where Io(t) is the amplitude ofthe current which was gradually decreased with time. These amplitude-modulated sinusoidal currents were generated in a home-made sine/cosine function generator and high voltage amplifier (Output max. \u00b1 280 V). To apply the pulses in constant-current mode, resistors of 50 kg or 210 kQ were connected in series between the outputs ofthe high voltage amplifier and the electrode cell, such that the resistance between the electrodes and the sample medium was negligible. To test that the sum of the effects of the electrophoresis and electroosmosis is proportional to the magnitude of the applied electric field, we measured the distances ofthe movement ofthe cells by applying rectangular current pulses with a fixed duration through one pair of the electrodes ofthe electrode cell. Then, these distances were found to be proportional to the amplitude of the pulses in the range used in the experiments with rotating electric fields as shown in Fig. 3. Measurement were performed at 25\u00b0C unless otherwise stated.\nCalculation of frictional coefficient and torque In order to estimate the frictional coefficient ofrotating tethered cell we treated the cell body as a prolate ellipsoid and used the formula: f =\nIwazawa~~ eta.Tru td fBctra lgla oolwazawa et al. Torque Study of Bacteria] Flagellar Motor 927"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001441_tmech.2003.816806-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001441_tmech.2003.816806-Figure7-1.png",
+ "caption": "Fig. 7. Visibility for a flat patch.",
+ "texts": [
+ " However, due to the high computational cost in calculating the intersection of resolution balls, the following indirect method is used: discretize the search space formed by the line of sight, the field-of-view and the in-focus region; test each discrete point to see if the distances between this point and the centers of the resolution balls are all less than the resolution ball radius . The visibility of the patch is guaranteed by the bounding box and the flatness constraint of the patch as long as the flatness constraint threshold satisfies . This condition is illustrated in Fig. 7. Any position in the intersection of the line of sight and the three constraint regions is an admissible look-from position. In practice, we choose the lowest solution position to obtain a larger image. A recursive algorithm is used to determine all the viewpoints for a flat patch. If the intersection of the line of sight and all the constraint regions of the current patch is null, which means no viewpoint exists that satisfies all constraints, we split the patch into two subpatches using the center plane of the bounding box along the length direction"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002455_j.precisioneng.2004.03.003-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002455_j.precisioneng.2004.03.003-Figure5-1.png",
+ "caption": "Fig. 5. Method of generating location of balls.",
+ "texts": [
+ " Let the number of balls be Z, then the total number, N, of location patterns of balls is expressed as follows. N = (Z! \u2212 1) 2 (7) Table 2 shows the data of the number of balls, number of patterns and elapsed time of calculation. The CPU of the computer used for the calculation is a Pentium 4 (1.8 GHz). For Z = 3, N = 1. In contrast, for Z = 10, N = 181440. There is a greater increase in N for a large number of Z. In addition, the elapsed time of the fc component for 72 patterns is approximately one second. The generation method for the location patterns of balls is shown in Fig. 5. Considering a polygon whose vertices are the centers of the balls, we can create a new location pattern of balls nontautologically inserting a new ball into the edge connecting the existing two balls. In the case of Z = 3, there is only one pattern. Therefore, if the fourth ball is inserted into one of the three edges (Z = 3, triangle), three location patterns of balls can be generated. The process to obtain the expected value of the fc component is as follows. (1) Let the balls be numbered virtually"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001066_1350650011541738-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001066_1350650011541738-Figure1-1.png",
+ "caption": "Fig. 1 Geometry and coordinates of the journal bearing",
+ "texts": [
+ " The basic equations governing the motion of an incompressible coupled stress fluid, in the absence of body forces and body couples, derived by Stokes are =:V \u02c6 0 (4) r DV Dt \u02c6 \u00a1= p \u2021 \u00ed =2V \u00a1 \u00e8 =4V (5) The ratio \u00e8=\u00ed has the dimensions of length square and, hence, characterizes the material length of the fluid. Proc Instn Mech Engrs Vol 215 Part J J03400 # IMechE 2001 at UNIV OF PITTSBURGH on December 19, 2014pij.sagepub.comDownloaded from A schematic diagram of the problem under study is shown in Fig. 1. The non-porous journal of radius R is approaching the homogeneous and isotropic porous bearing surface with a given velocity dh=dt at any circumferential section \u00f5. The lubricant between the journal and porous bearing is a Stokes coupled stress fluid and the body forces and body couples are assumed to be absent. However, the fluid in the porous matrix of the bearing is assumed to be purely viscous. This assumption is made to model the flow situation in which the polymer additives present in lubricant do not percolate into the porous matrix, i"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003091_b:jint.0000015344.84152.dd-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003091_b:jint.0000015344.84152.dd-Figure1-1.png",
+ "caption": "Figure 1. Single-link flexible joint manipulator configuration.",
+ "texts": [
+ " \u2737 Consequently, since the stability condition is expressed in terms of parametric uncertainties and design parameters, we can choose the design parameters of controller which guarantee the stability of the system with the given parametric uncertainties Ai and Bi (i = 1, 2, . . . , n). In this section, the validity and effectiveness of the proposed controller are examined through the control simulation for a single-link flexible joint manipulator. In the simulation, we examine the effects of parametric variation on behaviors of the closed-loop systems with the proposed control scheme. In order to apply the suggested controller, we need a Takagi\u2013Sugeno fuzzy model representation of the manipulator. Consider the single-link flexible joint manipulator shown in Figure 1 whose dynamics can be written as x\u03071 = x2, x\u03072 = \u2212MgL I sin x1 \u2212 k I (x1 \u2212 x3), (4.1) x\u03073 = x4, x\u03074 = K J (x1 \u2212 x3) + 1 J u, where I = 1 kg m2, J = 1 kg m2 are, respectively, the link and the rotor inertia moments, M = 1 kg is the link mass, k = 1 N/m is the joint elastic constant, L = 1 m is the distance from the axis of the rotation to the link center of mass and g = 9.8 m/s2 is the gravitational acceleration, respectively. We first transform the nonlinear system to the normal form [15] with z1 = x1 as z\u03071 = z2, z\u03072 = z3, z\u03073 = z4, z\u03074 = a(z) + b(z)u, (4"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002368_910530-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002368_910530-Figure2-1.png",
+ "caption": "Figure 2 -- Sealing tip manufacturing methods",
+ "texts": [
+ " Instant gross leakage ensues if extreme changes occur, such as reversing seal geometry by installing the seal backwards. Researchers also agree that all properly functioning seal designs will pump oil from the air side across the contact band into the oil sump (14). This pumping action must be maintained over the life of the seal to ensure reliability and long life. In some cases, projections are molded on the air side of the report describes studies that linkseal reliability and pumping ability to asperity formation. WEAR MECHANISM The sealing tips of radial lip seals can be manufactured in two ways (Figure 2). The old method trims the rubber cap from the oil side, leaving a molded surface on the air side and a trimmed surface on the oil side. The modern method accurately forms the seal tip with molded surfaces on both air and oil sides. The benefits of molded lip seals and deficiencies of trimmed lip seals have been previously described (1 5). Both methods of sealing tip manufacture yield the same result when the seal is installed on a shaft. The molded surface of the air side of both molded and trimmed tip seals contacts the shaft (Figure 3)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000888_s1350-6307(98)00024-7-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000888_s1350-6307(98)00024-7-Figure3-1.png",
+ "caption": "Fig[ 3[ \"a\u00d0d# Deformation in the components just before the accident[ \"e# Hypothetical sketch based on observations in Figs 3a\u00d0d[",
+ "texts": [
+ "i# where it seemed that material was removed due to impact\\ a high concentration of Fe\\ Cr\\ Si\\ Al and Cu was detected[ It seems that the material of the cage was smeared probably at the inner race _rst and then extensive compressive:shear stresses between the ball and the outer race resulted in chipping or shearing of the ball material[ Smearing on the outer race is accompanied by deformation\\ as is evident from the deformation bands near the surface in Fig[ 5[ Three di}erent regions were analyzed and the results are summarized in Table 1a^ the _rst two regions were big enough to permit analysis at a couple of locations[ In all the locations cage material was smeared[ Region I contained a signi_cant amount of Ag showing that the cage got smeared when the coating was intact[ Analysis at Region III\\ on the other hand\\ did not show the presence of an Ag coating\\ indicating that the cage had already been distressed to the level that its coating was completely stripped o} before smearing at Region III[ Micrographs in Fig[ 3c show the condition of smearing on the inner race[ The LHS was quite deformed and damaged[ Figure 3c!i shows the seat of the race where extensive smearing and deformation is clearly visible[ Four di}erent locations\\ marked in Figs 3c!vi and c!vii\\ were analyzed and they indicate the presence of smeared cage material at Regions II and IV^ see Table 1b for the analysis report[ At Region II\\ Ag is also present indicating that when the cage got smeared here the coating was at least partially intact[ No bearing component was found to contain Cr\\ Si\\ Al and Mg in the amounts detected in Region III of the inner race[ Particles rich in Si and Al and containing Mg were retrieved from the lubricating oil and could be transported to the inner race from some other source through the lubricant[ The material protruding from the RHS of the race \"Fig[ 3c"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000385_s0045-7949(98)00165-5-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000385_s0045-7949(98)00165-5-Figure3-1.png",
+ "caption": "Fig. 3. Simply supported square laminated plate (\u00aeve graphite-epoxy laminates) geometry and material properties.",
+ "texts": [
+ " The integration across the thickness is performed explicitly, whereas the integration over the surface of every interface is made by means of a three-point Gauss quadrature. Again it is possible to use the condensation technique across the thickness in order to reduce the number of calculations. The procedure consists now in eliminating the global displacements of the lower interlaminar surface ak for every layer k as a function of a k + 1 and a0 by means of an expression similar to Eq. (11). Further details can be found in [12]. The \u00aerst example studied is a graphite\u00b1epoxy simply supported plate. The geometry and material properties are shown in Fig. 3. We consider \u00aeve laminates with orientations 08/908/08/908/08 and thickness h 6 = h 4 = h 6 = h 4 = h 6 : The distributed load over the plate is given by q= q0 sin px/a sin py/a. For symmetry reasons only a quarter of plate was analyzed. The discretization is shown in Fig. 3. The number of analysis layers was taken the same as the number of laminates. Table 1 shows some results for the vertical displacement at the center of the plate and the stresses in some characteristic points, for di erent side length/thickness ratios (a/h). In order to show the accuracy of the results, they are compared with the solution obtained by Stavsky [18] by means of the Classical Theory of Laminated Plates (CLPT) which is based on Kirchho 's hypothesis. Note the di erence of the results when the thickness increases"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002472_j.jsv.2004.04.037-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002472_j.jsv.2004.04.037-Figure1-1.png",
+ "caption": "Fig. 1. Coordinate systems of a gear pair at the pressure line.",
+ "texts": [
+ " In this paper a general method is presented for obtaining the unbalance response orbit based on the finite element approach of a gear-coupled two-shaft rotor-bearing system, where the shafts rotate at their different respective speeds. Specifically, analytical solutions of the maximum and minimum radii of the orbit are proposed. The method is then applied to the unbalance response analysis of a 600 kW turbo-chiller rotor-bearing system, having a bull-pinion speed increasing gear. In addition, the validity of the proposed analytical solutions of the orbit radii is tested against those obtained fully numerically. A displacement vector of a gear pair can be defined from the pressure line coordinate system as shown in Fig. 1 by qG0 \u00bc uG0 1 vG0 1 yG0 X1 yG0 Y1 uG0 2 vG0 2 yG0 X2 yG0 Y2 yG0 Z1 yG0 Z2 j kT ; (1) where u; v; yX and yY are the translational and rotary degrees of freedom and yZ the torsional degree of freedom, and the subscripts 1 and 2 indicate the driving and driven gears. From the equilibria of the generalized forces for each gear, the coupled equation of motion of a gear pair can be expressed by (a detailed derivation can be found from [3]) MG0 \u20acqG0 \u00fe CG0 \u00fe GG0 _qG0 \u00fe KG0 qG0 \u00bc QG0 ; (2) where MG0 ; CG0 ; GG0 and KG0 are the inertia, damping, gyroscopic and stiffness matrices and they are given in Appendix A by Eqs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002222_1.533555-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002222_1.533555-Figure10-1.png",
+ "caption": "Fig. 10 Simulation reference frames",
+ "texts": [
+ "1 Main Symbols DRatio 5 decimal ratio Mctb 5 work machine center to back Offset 5 work offset N\u0304 5 tooth flank unit normal vector V\u0304r 5 relative velocity vector ac 5 cutter angular position a3 5 work roll angle t 5 cutter tilt angle k 5 cutter swivel angle A.2 Simulation of Tooth Manufacturing. Both the generating process and operation of gear sets are based on the same basic concept, that of meshing elements. In the manufacturing process, meshing takes place between a cutter blade, whose rotation represents the shape of one tooth of a crown gear, and the work itself ~see Fig. 10!; in operation, meshing occurs between the contacting teeth of the pinion and gear. The fundamental equation of meshing is N\u0304\u2022V\u0304r50 (A1) which states that the relative velocity vector V\u0304r between contacting surfaces must be in a plane tangent to the meshing surfaces at any contact point. Equation ~A1! yields the equation of the generated surface in general reference frame Z. The surface equation is a function of three variables ac , a3 , and Sr , respectively the cutter angular position, the work roll angle, and the position of a point along the cutter blade edge: S5 f ~ac ,a3"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure5-1.png",
+ "caption": "Fig. 5. Transmission functions (a and b) and parabolic function of transmission errors (c).",
+ "texts": [
+ " The above described methods of worm pro\u00aele crowning of the worm yield that worm thread surface Rw and worm-gear tooth surface R2 are in point contact at every instant and the bearing contact is localized. However, meshing of Rw and R2 is accompanied by large transmission errors of undesirable shape that are caused by errors of alignment. The purpose of worm longitudinal crowning is to provide a predesigned parabolic function of transmission errors that is able to absorb transmission errors caused by errors of alignment. Fig. 5(a) shows that transmission function /2 /w of a misaligned gear drive is a piecewise discontinuous function. The theoretical transmission function of an ideal gear drive is a continuous linear function. The function of transmission errors determined for each cycle of meshing /w 2p=Nw is represented as D/2 /w /2 /w \u00ff Nw N2 /w; 15 where Nw is the number of worm threads and N2 is the number of gear teeth. The goal of longitudinal crowning of the worm is to obtain for each cycle of meshing such a transmission function /2 /w (Fig. 5(b)) that will cause a parabolic function of transmission errors (Fig. 5(c)) determined as D/2 /w \u00ffa/2 w; 16 where a is the parabola coef\u00aecient. It is important to recognize that the worm-gear lags with respect to the worm, if the transmission function is of the shape shown in Fig. 5(b). Then, the transfer of meshing from one pair of teeth to the neighboring one is accompanied with elastic deformation of contacting teeth and the contact ratio is larger than one. In case of a misaligned gear drive with imaginary rigid teeth, the contact ratio due to misalignment is one only. The desired parabolic function of transmission errors is obtained by plunging of the disk that generates the pro\u00aele crowned worm surface R 1 w . Thus, the worm thread surface will be crowned in the longitudinal direction also"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001321_s1350-6307(99)00009-6-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001321_s1350-6307(99)00009-6-Figure7-1.png",
+ "caption": "Fig. 7. Cracks in the cage U.",
+ "texts": [
+ " Cases of previous cage failures were reviewed. It was found that on-site reports of bearing failures indicated cracks in CMB cages but the matter was not pursued to check the failure mode. One such bearing from a similar used engine was obtained, which had undergone more than 300 h of operation before the cage was inspected and removed. The cage, designated as sample U, was subjected to laboratory investigations. Visual and stereographic examination of the bearing in the laboratory showed cracks in the cage (Fig. 7). Wear marks were visible on the contact surface of the cage and the outer race, see Fig. 8(a) and a higher magni\u00aecation micrograph of the worn band in Fig. 8(b). The chemical analysis of the regions which had undergone smearing is summarized in Table 4. In none of the cases was the Cu peak more dominant than the Ag peak, indicating that the coating was intact. The analysis of the region in general showed signi\u00aecant smearing of Fe on the surface. Most of the smeared material was iron containing Cr, probably coming from the outer race"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002514_135065003765714863-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002514_135065003765714863-Figure1-1.png",
+ "caption": "Fig. 1 Effective spread E of a DRTRB (DB) (left) and a DRTRB (DF) (right)",
+ "texts": [
+ " This is due to the bearing\u2019s ability to support large combined loads for a given envelope and mass. DRTRBs are used for their high load-carrying capacity, load in both axial directions being permitted, and also since the bearing width is smaller than in the case of a set of two single-row tapered roller bearings (TRBs). The load lines of a DRTRB (DB) diverge towards the bearing axis. Therefore such bearing arrangements are relatively stiff and can accommodate tilting moments, while the load lines of a DRTRB (DF) converge towards the bearing axis (Fig. 1), giving it more ability to rotate under moment loading. The effective spread E is a function of the bearing arrangement and contact angle. A wider effective spread usually acts to reduce the load on rolling element. However, under certain loading conditions such as high bending moment the rolling element load may increase with increasing effective spread. When looking for a high stiffness, it is necessary to take into account both rolling bearing stiffness and shaft bending. The system is statically indeterminate and the static equilibrium equations are insuf\u00aecient to solve the bearing reactions",
+ " In this case the distance between supporting bearings was chosen to be equal to l \u02c6 354mm. It can be observed that, when the axial compression dp exceeds the value of 0.04 mm, the shaft de\u00afection remains approximately constant for both the TRB in the DB arrangement and the TRB in the DF arrangement. From Figs 4 and 5 it can be observed that the DB or DF con\u00aeguration affects the amount of shaft de\u00afection. This is due to different abilities of the DB and DF arrangements [the effective spreads E for DB and DF arrangements are different (see Fig. 1) and therefore have different in\u00afuences on the bearing stiffness] to support the bending moments generated by the external radial load. The angular stiffness (due to the moment load) of the DB arrangement with larger spread E is higher than that of the DF arrangement with smaller spread. This result is consistent with ball bearing arrangement behaviour, where the `O\u2019-type assembly is known to be stiffer than the `X\u2019-type assembly (in terms of angular stiffness due to the moment load). Comparative results concerning the axial and radial bearing loads generated by the external loading applied to the shaft in straddle design for DRTRBs (DB) and DRTRBs (DF) are listed in Table 3"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.6-1.png",
+ "caption": "Figure 1.6. Path of a particle having the motion",
+ "texts": [
+ " Thus, x(P, t) = x0 + 2t3i + 2t2k. With x0 = x(P, 0) = -2i ft, we have, finally, the motion of P: x(P, t) = 2(t3 - 1) i + 2t2k ft. (1.31) We observe that the motion of P always is in the xz plane. To determine the path of P, we use ( 1.6) and ( 1.31) to obtain the follow ing time-parametric equations: x(t) = 2(t 3 -1 ), y(t) = 0, z(t) = 2t2 ( 1.32) Then elimination of the time parameter t yields the standard equation for the path of Pin the xz plane: ( X )2/3 z=z(x)=2 ~+1 . ( 1.33) Its graph is shown in Fig. 1.6. It remains to compute the distance traveled in one second. Using the for- x(P, 1) = 2(13 - I) i + 212k. 18 Chapter 1 mula provided for v(P, t), we find that the speed of P is given by v(t) = 2t( 4 + 9t2 ) '12 in accordance with ( 1.13 ). Then ( 1.25) becomes Hence, the distance traveled by P in the time t is ( 1.34) In particular, we see from ( 1.32) and ( 1.34) that after one second the particle is at the place x = 0, y = 0, z =2ft shown in Fig. 1.6, and it has traveled the distance s(l) = ; 7 [13 312 - 8] = 2.88 ft. We notice in closing that with the help of the path equation (1.32), the dis tance traveled in ( 1.34) also may be expressed as a function of z: 2 [( 9 )3/2 J s=s(z)= 27 4+ 2z -8 . D Example 1.7. An electron E is at rest at the position x0 = 2i + 3j- k m initially. Subsequently, it is observed that the electron has an acceleration a(\u00a3, t) = 12t2i- 6tj + lOk m/sec2\u2022 What are the position, velocity, and acceleration of E after 2 sec"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001941_eurbot.1997.633569-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001941_eurbot.1997.633569-Figure6-1.png",
+ "caption": "Figure 6: combination of MORTIMER and SPIKE",
+ "texts": [
+ " Taking into account the velocity of the platform's legs of about wb = 50 y, the velocities for the karthesian coordinates can be calculated: Every leg needs At = smaav;sman = 3s for a complete stretch. This results in a stroke of length in z-direction of 2Az = 200mm, whereas the velocity in z-direction can be calculated as w, = 6 6 7 . The calculations for the values w,, wy, w j , wp, wr can be performed similarly 4 Combination of StewartPlatform and Mobile Robots To compensate the acceleration and the shocks acting on an object the Stewart Platform with 6 degrees of freedom is electively installed on MORTIMER (figure 6) or on VIPER (figure 7) so that abrupt vehicle movements and accelerations affect the object in a smooth way. Figure 6 shows an arrangement for the experiments. A jar containing a liquid is situated on the upper platform. The platform has to equalize the accelerations, calculated by the data of the basic motor controller. On the left side, the whole system is moving with a constant velocity v 2 0. The upper platform is parallel to the bottom, because no acceleration is effecting the liquid. On the right side, the system increases in speed, so the platform has to compensate this movement by an inclination of the upper platform"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001419_robot.1991.131938-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001419_robot.1991.131938-Figure6-1.png",
+ "caption": "Fig. 6: Second Method to Select a Support Trajectory of Circling Gaits.",
+ "texts": [
+ " I t is possible that the selected support trajectory of leg 4 is outside the workspace of leg 4 or that the straight line M ~ M I and the circular path of leg 4 do not intersect. Under these circumstances, the turning gait is considered to be unstable. Similarly, we can select the support trajectories of leg 2 and leg 3. This strategy can be also applied to +y type, - z type and --y type wave-circling gaits. In the second strategy, the two support trajectories with larger available leg angular strokes do not necessarily pass through their workspace centers. Referring to Fig. 6 , the available leg angular stroke 91 is less than the largest leg angular stroke 9 4 . The support trajectory of leg 1 is also first selected. The points Q and Q\u2019 represent the two intersections of the straight line oM1 with boundaries of the workspace of leg 4. These two points may locate a t any two of the four boundaries, depending on the location 21 10 of turning center. Since the support trajectory of leg 4 is divided into three identical pieces, segment QQ\u2019 is accordingly split into three equal small segments by points M4 and Mi"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003173_b:tril.0000015200.37141.f5-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003173_b:tril.0000015200.37141.f5-Figure1-1.png",
+ "caption": "Figure 1. Photographs of the specimens made of SiC (a) Cylinder (b) Disk.",
+ "texts": [
+ " To whom correspondence should be addressed. E-mail: xlwang@tribo.mech.tohoku.ac.jp 1023-8883/04/0500\u20130253/0 # 2004 Plenum Publishing Corporation The specimens were made of stainless steel, bronze and silicon carbide (sintered without pressurization). Purified water, paraffin oil P60 and P60 with oiliness additive, i.e., 0.5% stearic acid, were used as lubricants. The properties of the oil are listed in table 1. Sliding tests were performed between the flat surfaces of a cylinder and a disk by rotating the cylinder. Figure 1 shows a pair of specimens made of SiC. The upper specimen is in the shape of a cylinder, which has a hole in center and two grooves \u00f04 0:5mm\u00de on the flat surface so as to supply lubricant to this surface. The Lower specimen is in the shape of a disk. The metal specimens have the same shape as that of the SiC shown in figure 1. The combinations of the specimens and lubricant are listed in table 2. In order to increase the load-carrying capacity of SiC in water, the flat surface of the disk was textured withmicropits arranged in a square array as shown in figure 2. Reactive ion etching (RIE) was used to produce micro-pits on the flat surface of the disk. RIE is a widely used method for the processing of MEMS and ICs. It ionizes a reactive gas by electric discharge, then accelerates these ions to sputter and react with the target"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001042_robot.1994.350911-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001042_robot.1994.350911-Figure3-1.png",
+ "caption": "Figure 3 - Planar Bodies in Contact",
+ "texts": [
+ " The bodies are modeled as rigid, except for the allowable local deformations, and thus respond to applied wrenches like a rigid body. Frictionless contacts can be thought of as a special case in which kt = 0. Rigid body contact forces can be found from looking at the results in the limit as kn and kt approach infinity. If the fingers and the body have stiffnesses k n l , ktl and kn2, kt2, respectively, then the composite stiffnesses, in the normal and tangential direction, are: k, - kl11klt2 k, - k,lk,2 knl + k n 2 k,, + kt2 3.1 Planar Kinematics Consider a body, B, in point contact with a finger, A, (see Figure 3a). Let the constants KA and KB be the signed curvature (the inverse of the radius of curvature) of the undeformed finger and body, respectively, at the point of contact such that the curvature is positive for convex surfaces. We wish to examine the stability of the grasp under small displacements of body B. To do this, we let uA be the arc length along the surface of object A (measured in the direction of xA) , with a corresponding definition for uB. W i t h t h i s p a r a m e t e r i z a t i o n , we g e t = 1, LA = -KA, 6 = 1 and LE = - K , ",
+ " Note further that Ax, and Ay, refer to the contact frame, but they can be related to other reference frames through appropriate transformations. We use a fixed frame 0 at an arbitrary point. If we let 'K, be the stiffness matrix from either Equation (1 1) or (17) (whichever is applicable), and (ldB Idy) be the coordinates of 0 as seen from loc, then the change in the wrench referred to the coordinate system at 0 for any infinitesimal rotation or displacement, due to contact i , is given by: where: . . Aw0= iTT 'K, iT Axo (18) cos '@ -sin'@ and l @ is the angle of rotation of the frame 0 with respect to the contact frame ioc (see Figure 3 for definition of a). 4.2 Constant External Forces Consider the gravitational force on body B acting through the center of gravity. We define a coordinate system, oCg, fixed in space and coinciding with the center of gravity, where the axes are aligned such that gravity acts in the ycg direction. A rigid body motion of body B will not change the gravitational force, but will result in changes in the moment about the origin of ocg, given by: 0 0 0 AxXca [ :Ica =[ ;g ; ;Ica[\";,] Or Awcg =% Axcg (19) where m is the mass of body B and g is the gravitational force",
+ " When the force displacement relations are added together and the results analyzed, we find that all equilibrium frictional two-contact point grasps are stable. A grasp with only one frictional contact does not have this property, however, and the following lemmas address these cases: Lemma 5: An equilibrium grasp with one frictional contact opposing a gravitational .force is stable (unstable) if ( K A + K,)r+cos@ is negative (positive). Here r is us defined in Lemma 2, and 0 is the angle of rotation of contact frame 2 with respect to contactframe 1 (see Fig. 3) . J.emma 6; An equilibrium grasp with one frictionless point contact and one .frictional point confucf (without gravity) is (positive), where the frictionless contact is contact 2, r is as defined in Lemma 1, and 0 is us defined in Lemma 5. 5.0 Discussion In this paper, we categorize all planar equilibrium grasps, and establish results which can be used to determine the stability of virtually all planar grasps (including indeterminate grasps) by examining the eigenvalues of the combined stiffness matrix"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001799_s0168-874x(02)00056-2-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001799_s0168-874x(02)00056-2-Figure3-1.png",
+ "caption": "Fig. 3. Schematic illustration of the conic surface of the rocker and the spiral surface of the workpiece at plane r = r0.",
+ "texts": [
+ " It can be expressed as M (r; ; z) = z \u2212 S 2 ; (8) where S is the feed per revolution. Thus, the outline of the contact zone is a cross line of the curved surface (Eq. (7)) and the curved surface (Eq. (8)). Its equation is z2(1\u2212 tg2 )\u2212 r2 sin2 tg2 + 2rz cos tg = 0; z \u2212 S 2 = 0: (9) A new method to numerically calculate the contour boundary of the contact zone for FEM is established according to the fact that the slope in the exit end of the contact zone is equal to that of the spiral feed, as shown in Fig. 3. As shown in Fig. 3, the curve equation of the conic surface of the rocker at plane r = r0 is g( ; z) = z2(1\u2212 tg2 )\u2212 r0 sin2 tg2 + 2r0z cos tg : (10) The slope at any point of the above curve is \u2212 @g=@ @g=@z = r20 sin cos tg 2 + r0z sin tg z(1\u2212 tg2 ) + r0 cos tg : (11) The slope of the spiral line at plane r = r0 of the workpiece is k =\u2212 S 2 r0 : (12) According to the fact that the slope at point A of the conic surface (Eq. (11)) equals to that of the spiral line of the workpiece (Eq. (12)) at r = r0, the following equation is established as r20 sin cos tg 2 + r0z sin tg z(1\u2212 tg2 ) + r0 cos tg =\u2212 S 2 r0 (13) then, we have z = kr0 cos tg \u2212 r20 sin cos tg 2 r0 sin tg \u2212 k(1\u2212 tg2 ) : (14) Substitution of Eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002163_027836499301200602-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002163_027836499301200602-Figure2-1.png",
+ "caption": "Fig. 2. Elliptical limit surface of a soft fingertip. The states of the two experiments discussed in Section 3 are indicated.",
+ "texts": [
+ "comDownloaded from 530 the friction between the smooth supporting surface and the card is smaller than the friction between the fingertips and the card, its effects may be noticeable. In the case of symmetric grasps, ri = r2, f = f2, Is = fs&dquo; mi = rn2, and m,s, = mS2; hence the subscript i can be dropped. The Coulomb friction model establishes constraints among the normal force and the tangential force and moment at each contact area. The limits on the tangential force and moment are described by a limit surface (Goyal et al. 1991), which can be approximated by an ellipsoid plotted in force/moment space (Kao 1990), as shown in Figure 2. Let us define as the ratio of the maximum moment, mmax. that the contact can sustain when the tangential force is zero to the maximum tangential force, p fn, that the contact can sustain when no moment is applied. In the limiting case, as the contact area becomes very small, the frictional moment approaches zero (A = 0) and the friction limit is simply ft < ~ fn, which corresponds to the familiar case of a point contact with Coulomb friction. It can be shown (Goyal et al. 1991) that for a given frictional force, f, and moment, m, on the limit surface, the orientation of the corresponding surface normal is related to the relative magnitudes of the linear and angular sliding velocities",
+ "38 N and 2.47 x 10-3 Nm, respectively. Therefore, A = 6.5 mm. The experimental results are compared with predicted values of (2\u2019 (using equation (8)) for the two cases in Table 1. In the first case, the fingertips are close together and they slide considerably with respect to the card; in the second case, the card pivots between the fingertips almost as though they were point contacts with friction. The two cases result in different ratios of tangential force and moment at the fingertips as shown in Figure 2, with correspondingly different ratios of translational-torotational sliding velocity. As another check on the limit-surface accuracy, the measured card velocity and fingertip velocities can be used directly to compute A cot o = vs,;~/c.vS,;F, without using force information (Kao 1990). This gives A cot ~b = 7.8 mm and 1.53 mm, for r = 15 mm and 75 mm, respectively. Then, using equation (8), one obtains predicted values of h of 0.156 rad/sec and 0.0446 rad/sec for the two cases. 3.1. Discussion The experimental and predicted angular velocities are very close for both sets of experiments",
+ "5%, and the difference in w obtained by using the measured fingertip and card velocities directly is 2.6%. In the case of r = 75 mm, the differences are 1.7% and 0.5%, respectively. Comparing the two cases, we observe that when the fingers are farther apart, the contribution of the term (A cot ~) to the angular velocity is less significant. Hence, the errors u1 h are less sensitive to the inaccuracy in A cot ~ or to the ratio of force and moment. In such cases, the location of ( f , m) on the limit surface is closer to the vertical (moment) axis, as shown in Figure 2. Table 1. Comparison of the Experimental Results of Sliding Manipulation at Freie Universitaet Berlin on May 8, 2015ijr.sagepub.comDownloaded from 533 As the plots show, the force measurements are noisier than position information, because small stick-slip vibrations were present. The sliding excited a 60-Hz vibration in the manipulator fingers. However, this vibration was well above the 12-Hz closed-loop bandwidth of the device. If one low-pass filters the force and moment information at 10 Hz, one can see that average forces and moments agree closely with those predicted by the equation of the limit surface",
+ "&dquo; As these &dquo;fingertips&dquo; are attached to the stationary supporting surface, the sliding velocity of the card with respect to them is simply the absolute velocity of the card. Consequently, it is not necessary to measure the force and moment at these contacts or to use limit surfaces to obtain their sliding velocities. In other words, the forces between the card and the supporting surface are experienced indirectly when solving for LD; their effect is to alter the forces and moments at the moving fingertips, shifting them to different locations on their respective limit surfaces (see Figure 2), with different ratios of translational-to-rotational sliding velocity. As a result, only the three-axis force sensor mounted at each moving fingertip is needed to provide the force and moment information for analyzing the motion. 4. Conclusions Quasistatic sliding analysis has been promoted in the literature as an approximate tool for predicting and planning sliding motions. The results of the (admittedly carefully controlled) experiments described in this article suggest that it can also provide accurate quantitative results provided that the main assumptions of the method (low average speeds and accurate knowledge of the average coefficient of friction and normal force) are met"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000617_s1526-6125(00)70021-1-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000617_s1526-6125(00)70021-1-Figure2-1.png",
+ "caption": "Figure 2 Three Typical Types of Five-Axis Machine Tool Configurations",
+ "texts": [],
+ "surrounding_texts": [
+ "Owing to the increasing requirement of enhancing a product\u2019s esthetics and performance, free-form surfaces, which can be defined as surfaces with variable curvature by higher-degree polynomials, are conventionally used in automotive, naval, and aeronautic industries, as well as in turbine blades, impellers, and plastic injection dies/molds. With the advent of commercial CAD/CAM systems and CNC machines, free-form surfaces can be machined with three- or five-axis machine tools through the tool path generation by software packages. To reduce preliminary work and increase cutting efficiency as well as workpiece accuracy, employing five-axis machining is increasingly prominent as compared to conventional three-axis machining, owing to the application of adding two rotational degrees of freedom such that spindle orientation with respect to workpiece may be varied while machining. However, industries frequently encounter difficulties in interfacing the CAM system with the machine control system. The interface is a software program known as the postprocessor, which converts the cutter location (CL) data created by CAM systems into the machine control data or \u201cG\u201d codes. Figure 1 illustrates that the postprocessor acts as the bridge between the CAM system and the machine tool. The CL data not only include the physical locations of the cutter, composed of cutter tip position and the tool orientation, but also the information regarding a machine tool\u2019s operation, such as tool change, feed rate, and coolant on/off. Because individual controls manufacturers do not adhere to an international standard, such as ISO 6983, the machine operation information processed by the postprocessor may be different according to various machine tool controllers; that is, different manufacturers may use different codes to define the same function. Consequently, the more variety of NC units and machine configurations used, the greater the number of postprocessors. The postprocessor plays a crucial role in a modern machine shop. Owing to the lack of standardization of code format for various machine tool builders, the postprocessor presented here concerns only the transformation from the cutter\u2019s physical locations to the desired machine tool\u2019s motions, including linear motions and rotary motions, which is the main part of NC programs. Methods to develop postprocessors for NC machine tools can generally be divided into two categories: three-axis and multi-axis. From the perspective of the three-axis postprocessor, the processing technology is straightforward and no coordinate transformation technique is required because the orientation of the cutter remains unchanged. Further details regarding the three-axis postprocessor can be found in Bedi and Vickers1 and Lin and Chu.2 From the perspective of the multi-axis (four- and fiveaxis) postprocessor, because of the varying cutter\u2019s orientation with respect to the workpiece, the coordinate transformation matrix must be introduced to obtain the desired equations for NC code; refer to Suh and Lee,3 especially for five-axis machining. On the other hand, with the two additional rotary degrees of freedom in the tool motion, various combinations may be synthesized to yield five-axis machine tool configurations. Consequently, the postprocessor for a five-axis machine tool is inevitably developed individually.4 For instance, Takeuchi and Watanabe4 presented the postprocessor method on two five-axis configurations. Warkentin, Bedi, and Ismail5 developed the technique of machining spherical surfaces and derived the five-axis NC code for one configuration. Moreover, Sakamoto and Inasaki6 classified the configurations of five-axis machine tools into three typical types. Recently, Lee and She7 presented the method for deriving the complete analytical NC code expressions for the above three kinds of fiveaxis machine tool configurations. Worth mentioning is binary cutter location (BCL), which is another approach used as an input to the NC controller with postprocessor function.8 R\u00fcegg9 proposed a generalized kinematics model for three to five-axis machine tools and implemented in a CNC controller. However, due to the high cost investment on the controller and the BCL data format not being widely accepted by users and machine tool builders,10 this concept is not popularly used for universal five-axis machine tools. The purpose of this paper is to extend the previous research proposed by Lee and She7 and develop the generalized postprocessor for effectively dealing with the universal five-axis machine tool\u2019s configuration. By adding four rotational degrees of freedom where two of them are applied to the fixture table and the other two are applied to the spindle, the generalized kinematics model of general five-axis machines can be established and the corresponding form-shaping function matrix can then be determined through the homogeneous coordinate transformation matrix. In addition, the desired analytical equations for NC data are obtained by equating the known CL data matrix and the form-shaping function matrix. Furthermore, the validity of this methodology is confirmed by implementing a trial cut on the five-axis machining center and verifying on the coordinate measurement machine (CMM) according to the proposed algorithms. 132 Journal of Manufacturing Processes Vol. 2/No. 2 2000"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002672_j.sysconle.2004.11.014-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002672_j.sysconle.2004.11.014-Figure5-1.png",
+ "caption": "Fig. 5. Situation in Theorem 3.3.",
+ "texts": [
+ " If the set A enclosed by this curve has finite measure , it is absurd, just as in the previous proof. So, the question we must answer is if S \u2208 A\u0304. But if it was the case, S would be the -limit of the bold trajectories and then S could not attract almost all the initial conditions of the original system. In order to see this, consider again the closed path constructed with the negative trajectory of z, the positive trajectory of y0 and a piece of the transversal section through z. We draw again the picture in Fig. 5. Then all the trajectories started outside this closed path must enter it to reach S and these can be done only through the piece of transversal section, which can be made arbitrarily small because of the dense assumption on the set of initial conditions attracted by the north pole N to the past. The counter-reciprocal version of the previous theorem is very interesting. Corollary 3.3.1. Consider the nonlinear system x\u0307 = f (x) with f \u2208 C1(R2,R2). Assume that the set f \u22121({0}) is finite in R2 and that there is a monotone Borel measure bounded at infinity"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003253_j.engfailanal.2004.12.035-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003253_j.engfailanal.2004.12.035-Figure4-1.png",
+ "caption": "Fig. 4. Shafts polishing process.",
+ "texts": [
+ " 1 shows the generic patterns of golf shafts which are comprised of a double bias layer followed by the prepreg of a straight layer on the internal mandrel. As shown in Fig. 2, after the completion of laying-up, wrapping is required to maintain the pressure upon the shaft. Polypropylene tape is usually used for wrapping and the line pressure of the shaft is about 30\u201340 kgf/mm. Fig. 3 shows the curing process of the shaft in a hot-air oven. The hardening time in this process depends on the types of resin but the shaft used in this experiment was kept in an oven at 125 C for 90 min. Fig. 4 illustrates the shaft polishing process, which removes its coating and optimizes its delicate surface and size. The characteristics of a golf shaft can be investigated using four different mechanical parameter tests [3]. These four tests are as follows. The frequency of the golf shaft can be defined by its cycles per minute (CPM) when a mass of 205 g iron is hung at its tip, with its butt fixed as shown in Fig. 5. In general, the frequency, which is often used as a means of quality evaluation for golf shafts following manufacture, is related to the deflection or flex of the shaft"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003515_j.jmmm.2004.04.084-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003515_j.jmmm.2004.04.084-Figure1-1.png",
+ "caption": "Fig. 1. Cross section of (a) IPM and (b) SPM motors.",
+ "texts": [
+ "jmmm.2004.04.084 believed to either directly or indirectly affect motor performance and can be quite dangerous to the motor. Therefore, it is necessary to investigate the effects of rotor eccentricity in permanent magnet synchronous motors. PM synchronous motors generally have two classifications: the popularly used surface permanent magnet (SPM) motor where magnets are mounted on the rotor surface, and the buried or interior permanent magnet (IPM) motor where magnets are mounted inside the rotor (Fig. 1). In this paper, a finite element-based study with and without rotor eccentricity for IPM and SPM synchronous motors is presented. The results including air gap flux density, EMF, cogging torque and average torque are computed from the finite element model. d. Fig. 1 shows three-phase, 6-pole, Y-connected, 8-hp and 36-slot IPM and SPM motors used in the study. Both motors have the same specifications except for different magnet configurations. A twodimensional (2D) cross-section of the motor is modeled using the well-established 2D time-stepping vector potential formulation [7]. The model includes the effects of magnetic saturation, circuit coupling, an external power system, slotting effects and rotor motion. At each time step, the model computes magnetic quantities like magnetic field distribution within the motor and mechanical quantities like position and torque"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002254_3.46181-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002254_3.46181-Figure2-1.png",
+ "caption": "Fig. 2 Aeroelastic model layout-spars, actuators, and hinge attachments.",
+ "texts": [
+ " The wing box consisted of nine aluminum-reinforced balsa sections, and the leading- and trailing-edge control surfaces each consisted of nine aluminum-reinforced balsa sections. The wing sections were attached to a wing box spar and control surface sections were attached to four separate control surface spars. Springs, simulating both actuators and hinges, were used to attach each of the control surface spars to the wing box sections. Each of the balsa sections was mass balanced so that mass, static unbalance, and mass moment of inertia properties corresponded to full-scale values. Figure 2 shows the section layout of the scaled aeroelastic model. Model geometry was scaled to be identical to the full-scale preliminary design. Full-span wing aspect ratio was 3.75, the taper ratio based on tip and fuselage centerline chords, 0.218, and the thickness to chord ratio, 3.8%. The leading-edge sweep was 34.3 deg aft and the trailing-edge was unswept. Airfoil selection was based on full-scale specifications, but was modified to simplify both model fabrication and model trim in the tunnel. A symmetric, 3",
+ " For a swept elastic axis, the pitching moment causes some wing bending, which shifts the effective elastic axis forward, as shown in Fig. 3. The set of influence coefficients was generated using the full-scale NASTRAN finite element model. Bending (El) and torsional (GJ) stiffnesses were determined using the cantilever beam equations. Figure 4 shows the scaled stiffness distributions along the wing box determined from the finite element model. The kinked beam spar design, shown in the layout in Fig. 2, was selected to model the wing box stiffness. NASTRAN analyses indicated that this spar design deformed with deflection and bend/twist characteristics that approximate the influence coefficient description. More precision in matching the influence coefficient description might have been attained through design of a more complicated and costly structure. However, past experiences in the construction of low-speed aeroelastic models has shown that the simulation of actual aircraft structures by beams located on the elastic axis will give acceptable results",
+ " Actuator and Hinge Modeling Full-scale actuator stiffness values were simulated by springs in the form of aluminum brackets that connected the control surface spars to the wing box. Four actuators connected the inboard leading-edge surface. The outboard surface was connected with one leading-edge actuator and two hinge points. Because the leading- and trailing-edge surfaces were segmented, a trailing-edge outboard actuator was added to the outboard flaperon. In addition to this actuator, the outboard trailing-edge control surface was connected at two hinge points. The inboard trailing-edge surface was connected by one actuator and three hinges. Figure 2 depicts the master layout containing the location of all the spars, actuators, and hinges. Hinges were constructed of springs with low rotational stiffness to reduce the damping normally encountered with ball D ow nl oa de d by U N IV E R SI T Y O F O K L A H O M A o n Ja nu ar y 25 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .4 61 81 bearing hinges. Each hinge consisted of a 1.5-in. piece of angled beryllium copper, which was connected to three small steel attachment fittings"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003153_146441905x63322-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003153_146441905x63322-Figure3-1.png",
+ "caption": "Fig. 3 Coordinate systems of the dynamic model of the gantry crane",
+ "texts": [
+ " The trolley moves along the rails attached to the gantry perpendicular to the pier, so it basically has one DOF. Nevertheless, owing to the structural flexibility of the gantry, the operator senses vertical accelerations while hoisting or lowering the container, therefore another DOF is required to model this direction of motion. The spreader is attached to the trolley via cables and has all six DOFs. The bodies of the dynamic model of the gantry crane and the coordinate systems attached to the bodies are presented in Fig. 3. The model has a total of nine DOFs. Owing to possible singularities during numerical solutions, a more stable behaviour can be achieved using more than three rotational coordinates. In this case, four Euler parameters were selected. As the four parameters increase the DOFs, normalization constraint of the coordinates is required [1\u20134]. The generalized coordinates q that fully describe the DOFs of the system can be expressed as q\u00bc\u00bdZg Xt Yt Xc Yc Zc u0c u1c u2c u3c T\u00bc\u00bdRTuT T (1) where R\u00bc \u00bdZg Xt Yt Xc Yc Zc T and u\u00bc \u00bdu0c u1c u2c u3c T (2) The normalization constraint equation of the Euler parameters is C(q)\u00bc uTu 1\u00bc 0 (3) Using Lagrange\u2019s method, it is possible to model the connecting joints between separate bodies by using constraint equations that describe joints between bodies"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001508_978-1-4615-2135-8_1-Figure1.4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001508_978-1-4615-2135-8_1-Figure1.4-1.png",
+ "caption": "Figure 1.4 The centre line distance (Cd governs the maximum power transmittable from the motor to the shafts and the screw conveying volume.",
+ "texts": [
+ " The main disadvantage of the piston type is in the valve and ball arrangement where any solid matter, either as a foreign body or natural in the feed stock, will prevent the ball seating in the valve. This drastically reduces the positive nature of the pump and although it may be apparent that the pump is functioning well under atmospheric pressure, any back pressure caused by partial blockage in the feed pipe will be disastrous. The degree of intermeshing is determined by the shaft centre line distance (CL , Figure 1.4) and the desired screw to screw clearance, with zero clear ance being fully intermeshing. Many manufacturers of extruders claim machines which are self-wiping but this implies zero clearance which would give severe mechanical wear from metal to metal contact. In reality a compromise is found and screws are made as fully intermeshed as pos sible. The volume of material that screws can convey and the power they can transfer in pumping and heat generation is a design optimisation which is made to suit different products"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002381_robot.2001.933052-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002381_robot.2001.933052-Figure4-1.png",
+ "caption": "Figure 4: Construction of virtual joint model (n = 3)",
+ "texts": [
+ " az( t ) = {(\")T(\")}-'(\")T(\") (7) 4 Virtual Joint Model In this section, we describe ii model construction of flexible manipulators based on the virtual joint model by Yoshikawa e t al. [4] 4.1 Model Constructioin In the virtual joint model, which is one of the lumped parameter models, each flexible link is divided into some virtual rigid links connected by virtual passive joints. The link flexibility is represented by virtual springs and dampers attached to the virtual passive joints. As shown in Fig.4, each of\u2019 N flexible links is divided by n virtual passive joints. The divided virtual rigid links are numbered link :io, i l , \u201d \u2018 , in from the manipulator base (Fig.4 is an example of n = 3 ) . l i j is the length, 1,ij is the center of mass, mzj is the mass, Iij is the inertia moment around the center of mass of link i j ( j = 0,1, . . . , n). The virtual passive joint attached to the base of link ij ( j = 1 , 2 : . . . ,n) is called joint ij. The displacement of the virtual passive joints on link i is +i(t) = [4il, 4i2, . . . , & I T . The damping coefficient and spring constant of joint ij are respectively Di,?, Kij . 4.2 Dynamics The equations of motion of a flexible manipulator based on the virtual joint model are given by M11($)8 + M12($)4 + h l ( w i J ) = 7- (8) M21($)8 + M22($)4 + hz(yj, 4) + D 4 + K 4 = 0 Mll, M12, M21, M22 are the inertia matrices, hl, h2 are the vectors containing centrifugal, Coriolis, gravity and other nonlinear force, D = diag[Dll ,D12,"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003922_bf02844162-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003922_bf02844162-Figure7-1.png",
+ "caption": "Figure 7 A schematic of the rigid body Newtonian oblique impact model.",
+ "texts": [
+ " In order to achieve this logical combination, a Newtonian impact model was considered. Daish (1974) first proposed the applicability of a Newtonian impact model for cricket and his work was later developed by Carr\u00e9 et al. (2000). Essentially, the Newtonian impact model allows for no deformation of either the surface or the ball and calculates the ball rebound dynamics using a combination of friction and restitution measurements. Whilst it is inaccurate to describe the cricket ball and pitch as rigid bodies, the model provides some useful insights. Fig. 7 shows a schematic of the rigid body model. The cricket ball arrives with a spin rate, \u03c9in (positive = topspin, negative = backspin), a horizontal velocity, Vxin, and a vertical velocity, Vyin. Two forces act on the ball during impact, a normal reaction force, F, and a frictional force equal to the product of the coefficient of friction and the normal reaction force, \u00b5F. After impact, the ball rebounds with the velocities of Vxout and Vyout and a spin rate of \u03c9out. The ball\u2019s radius is denoted by r and its mass is m"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001325_jsvi.2000.3040-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001325_jsvi.2000.3040-Figure5-1.png",
+ "caption": "Figure 5. Response of the axially moving string under a sinusoidal point load and controlled by the &&simulation'' control forces of Figure 3.",
+ "texts": [
+ " The latter is suitably termed &&simulation'' because it can be achieved only in simulations but not in real time control. The &&real time'' and &&simulation'' control forces for this example are plotted in Figures 2 and 3. The corresponding responses of the controlled system are shown in Figures 4 and 5. In Figure 4, it is seen that the controlled vibration does not go to zero as a result of nonzero motions at the boundaries when the control forces are applied at t c . However, the controlled amplitude is much smaller than the uncontrolled one. In Figure 5, as predicted by the control laws, the vibration is suppressed to zero in x)a 1 and x*a 2 . Comparing Figures 4 and 5, it is seen that the control is still e!ective in the presence of non-zero initial conditions at non-\"xed boundaries. For this type of feedforward control, disturbances in the uncontrolled regions and boundary excitations can be attenuated by feedback control [36]. Numerical results show that similar control e!ects are obtained when di!erent types of boundary conditions are considered and when a random excitation force is applied"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002333_a:1025991618087-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002333_a:1025991618087-Figure3-1.png",
+ "caption": "Figure 3. The open-constraint coordinates and the constraint reactions.",
+ "texts": [
+ " , m7,m7, JC7) is the constant generalized mass matrix related to p, mi and JCi are the masses and mass moments of inertia with respect to Ci of the segments, h = [(h(1))T . . . (h(7))T ]T contains the generalized applied forces on the bodies due to the gravitational forces, reactions from the trampoline (for segment 4) and control torques (as an example, for the said segment 4, we have h(4) = [\u2212Rx m4g\u2212Ry MA+\u03c43]T ), C(p) is the 12\u00d721-dimensional matrix of constraints due to the kinematical joints, and the Lagrange multipliers \u03bb = [\u03bb1 . . . \u03bb12]T are the reaction forces in the joints, shown in Figure 3. The 21 absolute coordinates p are dependent because of the joints in the system, modeled by 12 kinematic constraints on the bodies. Physically, the constraints express the prohibited relative translations in the joints. By introducing 12 local coordinates z = [z1 . . . z12]T to describe these prohibited relative motions, say open-constraint coordinates, the constraints on the bodies are z = 0. Since z can be expressed in terms of p, the constraint equations at position and velocity levels, given in implicit forms [13], are: z = (p) = 0, (2) z\u0308 = C(p)p\u0307 = 0, (3) where C = \u2202 /\u2202p is the constraint matrix used in Equation (1)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000417_a:1008980606521-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000417_a:1008980606521-Figure1-1.png",
+ "caption": "Figure 1. Schematic drawings of the TUM walking machine and the Indian stick insect, Carausius morosus, upon which it is modeled, showing the body-centered coordinate system, the joint axes, and the joint angle designations. The machine lacks the long abdomen of the insect and, for economy in fabrication, all legs have the same dimensions, but it shares the scaling of the three leg segments as well as the inclinations of the axes of the basal joints.",
+ "texts": [
+ "eywords: hexapod, walking machine, neural net, cybernetics, Carausius morosus Walking is one of many behaviors where machines still lag notably behind the performance of animals, so it is natural to examine walking in animals for hints to improve the performance of machines. The animal discussed here is the stick insect (Fig. 1(a)) or walking stick\u2014a slow, long-legged hexapod adapted for locomotion on complex substrates consisting of branches and leaves. Like most other insects the stick insect can walk with all different orientations to gravity; it can walk upright on flat or uneven surfaces, climb or descend vertical surfaces, and walk inverted hanging from \u2217Present address: BGES/Cleveland State University, 2399 Euclid Avenue, Cleveland, OH 44115-2406. branches or leaves (e.g., Cruse, 1976a). Natural surfaces provide more-or-less rigid mechanical coupling among the legs in contact with the substrate, but the stick insect can also walk with good coordination on mercury or other slippery surfaces where the legs are mechanically uncoupled (Cruse and Graham, 1981)",
+ " In contrast to the bottom-up description just given, a top-down analysis beginning with the global task naturally leads to the choice of control principles that explicitly ensure adequate global performance, in other words, control mechanisms incorporating some form of global optimization. This in turn suggests the need for a single central controller to supervise the global optimization. This central instance would need information on the state of all six legs, that is, information on the current step phase and the angles, velocities, and torques at all the joints. Results in the stick insect and in the modeling work do not support the need for an architecture based on a central controller. Each leg of the stick insect (Fig. 1(c)) has three major joints and three major segments, which lie approximately in a plane. The two distal joints, the coxatrochanter joint and the femur-tibia joint, essentially are hinge joints providing one degree of freedom each; they are primarily responsible for leg elevation and leg extension, respectively. The subcoxal joint, the proximal joint linking the leg to the body, has a more complex structure providing two degrees of freedom. The primary movement is that of a hinge joint with its axis tilted from the vertical: this degree of freedom is primarily responsible for the forward and backward movement of the leg",
+ " For example, if the joint angle changes a lot in one time interval, the controller attempts to make it change a lot in the next. The low-pass characteristic provides an upper limit to velocity, such as would be imposed by the inertia and the biomechanical limits of a skeletal muscular system. The role of the physical interaction via the substrate is to cause a change at any single joint to impose physically realistic changes on all the other joints. Imagine a hexapod standing motionless in a configuration similar to that of Fig. 1(a) but with all six legs on the ground. Then let the femur-tibia joint of the left front leg begin an active flexion, pulling the animal forward. The mechanical coupling acting on the elastic skeletal muscular system will cause changes in the other 17 joints, although the net effect of their own controllers will reduce movement amplitudes, including that originally commanded for the femur-tibia joint of the front leg. The mechanical interaction ensures that the whole system changes in a consistent and physically realistic manner, that is, all the connections between segments and between tarsi and substrate are maintained"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002746_0278364905060149-Figure29-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure29-1.png",
+ "caption": "Fig. 29. Arrangement of measurement device for frame deformation in another configuration.",
+ "texts": [
+ " If the distances between the surface plate and the joint supports, u1 \u2212 u6, are considerably long, some non-contact displacement sensor systems (e.g., a laser interferometer system) are utilized as shown in Figure 27. The combination of the sensor and the rod also measures the distance changes among the three joint supports, t1 \u2212 t3. In the PKM shown in Figure 2, the mechanism is suspended from the frame. This compensation system can be successfully utilized even if other configurations of the PKM are adopted. For example, a PKM can be held in the inverted position as shown in Figure 28. Figure 29 shows another configuration of a PKM that is manipulating the workpiece. The compensation device for the frame deformation, described in Section 4, was installed in an experimental CMM (Oiwa 1997, 2000) as shown in Figure 8. This CMM uses a parallel manipulator with three degrees of freedom, which is shown in Figure 2(b). A triangular-prism-shaped aluminum truss frame supports the manipulator through three spherical joints. A surface plate made of low-expansion cast iron at UNIVERSITY OF BRIGHTON on July 11, 2014ijr"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002991_sis.2003.1202253-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002991_sis.2003.1202253-Figure2-1.png",
+ "caption": "Figure 2. Relative sensory range limitatinnS.",
+ "texts": [
+ " However, if there is no information from the current state, the higher behavior layer of the architecture will inhibit and subsume the lower layer(s) as required by the subsumption scheme. The tight coupling between the sensordstate and behaviors is responsible for the UAVs' reactive maneuvers. The architecture is divided into three main subcomponents: sensors, actions, and behaviors. 4. SENSORS The sensors are the \"eyes\" and \"ears\" of the UAV. A UAV's behavior is greatly dependant on its sensors. Nonetheless, the UAV's sensing capacity bas limits as depicted in Figure 2. We assume that the target emits a detectable signal that can be sensed by a UAV at a relatively long range, The detection range (the larger circle in Figure 2) is a parameter that is dependant on the effectiveness of the UAV's target sensor. As the UAV detects the target signal, it is capable of determining the relative distance and direction to the target. The ranges for local-communication and viaion, for simplicity, are presumed to be the same (the smaller circle in Figure 2). The vision range is the distance at which the UAV can visually sense obstacles. The simulation assumes the imaging technology is able to determine the relative distances and directions of obstacles so the UAV can take evasive action. The local-communication range is the distance at which the UAV can receive or broadcast short-range messages from or to its neighbors. Normally the detection range is greater than the local-communication or vision range. 5 . ACTIONS The output of the architecture is a vector composed of two motor mechanisms: rotational and forward velocity"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002793_j.jsv.2005.03.024-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002793_j.jsv.2005.03.024-Figure9-1.png",
+ "caption": "Fig. 9. Edge excited plate strip.",
+ "texts": [
+ " Nevertheless this modification will have no effect on the static stiffness\u2019 discussed in the previous section, only on the characteristics above the first side-wall resonance. The example here will only include one wavetype and the shear waves generated by the belt circumferential or longitudinal motion are chosen, being the most simple, described by a secondorder differential equation. It will be shown that the effects depend upon the relative sizes of the side-wall (or plate), free wavenumber and the excitation wavenumber from the belt at the boundary. Fig. 9 shows an infinite orthogonal plate strip of width ly, representing the side-wall. The wavenumber ky, across a strip of width ly, is very similar to that of the one-dimensional system of the same length, considered previously. However, for the strip, the wavenumber ky has a larger attenuation part due to the extra distance actually travelled between boundaries by the nonnormal wave front. Two methods of finding this damped wavenumber in the y direction are obtained by considering the in-plane response of the strip to an inexorable x displacement U0 exp\u00f0 ikxx\u00de, travelling in the x direction at the boundary y \u00bc 0",
+ " (37a) This is now an equation for one-dimensional waves in the y direction; the complex wavenumber is the same as before but now with extra attenuation dependent upon the angle of incidence to the boundary y k\u0302y \u00bc k\u0304y ik0x cot y. (37b) For normal incidence there is no extra attenuation, while for grazing incidence the attention becomes infinite because of the increased path, i.e. lx becomes infinite. a\u0302y is the attenuation and phase change as the wave between the boundaries separated by distance ly a\u0302y \u00bc exp\u00f0 ik\u0302yly\u00de. (37c) The complex wavenumber k\u0302y can actually be found much more directly, but without physical interpretation from the vector summation of wavenumbers seen in Fig. 9 k\u0302y \u00bc ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi k\u0304 2 k2 x q ; k\u0304 2 \u00bc k\u0304 2 x \u00fe k\u0304 2 y. (38a,b) The real and complex wavenumbers are defined in Eq. (35). It is to be noted that the purely real wavenumber kx imposed on the boundary is used in Eq. (38a). If the loss factor Z, in directions x and y are the same, then Eq. (38b) becomes k\u0304 2 \u00bc k2 x \u00fe k2 y 1\u00fe iZ . (38c) By making this substitution into Eq. (38a) the modified wavenumber in the y direction is k\u0302y \u00bc kyffiffiffiffiffiffiffiffiffiffiffiffiffi 1\u00fe Z2 p ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 \u00f0Z cot y\u00de2 iZ\u00f01\u00fe cot y\u00de2 q ; cot y \u00bc kx ky "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002571_cca.1996.558742-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002571_cca.1996.558742-Figure3-1.png",
+ "caption": "Figure 3: Variation of length in a flow field",
+ "texts": [
+ " 2Recall that a virtual displacement is an infinitesimal displacement at fixed time. a n-dimensional space. That means there is only 2- dimensional space left in which the velocity vectors have to lie. Thus it can always be represented as a rotation in a 2-dimensional plane. It is also well known that all the eigenvalues of 0 are imaginary and correspond to n orthogonal eigenvectors. 4. Contracting regions Consider two neighboring Lagrange particles in the flow field, and the line vector ds between them (Figure 3). The squared distance between these two Lagrange particles can be written [Fluegge, 19721 ( d S ) 2 = (6x)2 The rate of change of any length in the flow field is 3For non-Cartesian coordinates length is defined in tensor analysis as 6x,glJ6x3, where gzJ represents the metric tensor and thus the metric of the system. thus of the form d - ( S X ) ~ = 2 6xTF(x, t)Sx = 6xTE(x, t)Sx ( 2 ) dt since O(x,t) is skew-symmetric. The rate of strain tensor E, which is symmetric, can in turn be written\u2019 E ( x , t ) = V T ( x , t ) A ( x , t ) V ( x , t ) (3) where V ( x , t ) is a matrix of eigenvectors and V T ( x , t ) V ( x , t ) = I, and A(x , t ) is a diagonal matrix containing the real eigenvalues of E(x , t ) "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001852_icpr.2002.1047389-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001852_icpr.2002.1047389-Figure1-1.png",
+ "caption": "Figure 1. Symmetrical points seen from symmetrical cameras",
+ "texts": [],
+ "surrounding_texts": [
+ "1. Introduction\nSymmetry is a rich source of information in images. Mirror symmetry (also called bilateral symmetry) is a property shared by many natural and man-made objects. A 3-D object exhibits mirror symmetry if there exists a plane that separates the object into two (identical) chiral parts. The plane is called symmetryplane. For each point of such an object, there exists an identical symmetric point that also belongs to the object. A line joining two symmetric points is called a symmetry line. All symmetry lines are perpendicular to the symmetry plane, which by construction contains all symmetry pair midpoints.\nMethods to exploit symmetry and infer constraints on the 3D reconstructed shape of the objectlscene have a long history in Computer Vision. Based on the assumption that \u201ca skew symmetry depicts a real symmetry viewed from some unknown angle\u201d (Kanade [5]), a large number of approaches rely on the analysis of skewed symmetries in images to infer constraints on the 3-D geometry of\ndepicted objects. In most cases, (scaled) orthographic projection is assumed (see e.g. [7][2]). A more limited number of studies deal with symmetry observed under perspective projection. Some (e.g. [11][6]) use the vanishing point of symmetry lines, whose computation is unstable unless the perspective distortion is severe. Different studies make use of the epipolar geometry arising from the bilateral symmetry of a scene in a single perspective view (see e.g. [9][12][10][4]).\nWe establish more general epipolar projective properties of single views of mirror symmetric scenes, and apply them in a different context: we perform Euclidean 3-D reconstruction of mirror symmetric objects from a single perspective view using traditional 2-view stereo geometry. This is allowed by the mirror-stereo theorem. Theorem: One perspective view of a mirror symmetric scene, taken with an arbitrary projective camera, is geometrically equivalent to two perspective views of the scene\nthe unknown 3-0 symmetry plane. We show how to extract the epipolar geometry relating the two views from the single input image. Classical 2- view stereo results can then be applied (see e.g. [ 1) or [3]), and the concepts of fundamentaVessentia1 matrix, epipolar geometry, rectification and disparity hold. If the camera is calibrated, we show how to synthesize the image generated by the original camera placed symmetrically, in order to be able to use traditional 2-view stereo tools to obtain an Euclidean reconstruction of the scene.\nThis paper is organized as follows. In section 2 and section 3, we establish two lemmas used in the proof of the mirror-stereo theorem, given in section 4. In section 5, we show in the case of a calibrated pinhole camera, how to build a virtual view taken by the same camera placed symmetrically in location and orientation. Examples of Euclidean 3-D reconstructions obtained from such pairs with an off-the-shelf stereo package are presented. A summary of the contribution concludes the paper in section 6 .\nThroughout the paper, the approach and notation used are consistent with that of [3].\nfrom h v o projective cameras symmetrical with respect to\n1051-465U02 $17.00 Q 2002 IEEE 12",
+ "2. Virtual view respect to the (R, y , z ) plane is x = Z X , where\nLemma 1: The image of a scene that is symmetric with respect to an unknown plane, formed by an arbitrary projective camera, is identical to the image of the scene formed by the (virtual) projective camera symmetric of the Jirst one with respect to the scene's 3-0 (unknown) symmetry plane.\nWithout loss of generality, we place the origin R of the world Euclidean, orthogonal, right-handed coordinate system ( R , x , y , z ) on the symmetry plane, which we also define as the (R, y , z ) plane. The setting is illustrated in figure I . Let X denote a world point represented by the\nhomogeneous 4-vector 1 . Let x denote the cor-\nresponding image point represented by a homogeneous 3- vector [U v 4 T . A general projective camera is defined\nby a 3x4 projection matrix P = M[II - C'] , where M is a\n3x3 matrix, and C denotes the inhomogeneous 3-vector of the camera center coordinates in the world coordinate system. X is mapped to x according to the relation\n[ I'\nx = M[II - C ] X . By construction, the world point symmetric to X with\n10 0 0 11 L \" I\nThus the image point X of the world point x seen by camera C is:\nP = M[II - C ] X = M[II - C ] Z X\nConsider now the virtual camera c, symmetrical of camera C with respect to the object's symmetry plane. By construction, its center is c = ZC , and it projects a world point X into the image point x' such that:\nx' = M[II - ? ] X , where fi = M Z Replacing symmetric elements by their expression, we\nget:\nx' = MZ[II - Z C ] X = M[II - QZX = X and\nX' = M.z[II - ZC]ZX = M[II - CIZZX = x It follows that the image of a pair of symmetric points viewed by the real camera is identical to the image of the same symmetric pair viewed by the virtual symmetric camera, the actual image points of the symmetric points being reversed in the real and virtual view. Q.E.D.\n3. Through the looking glass\nLemma 2: In stereo pair of images of a mirror symmetric scene, taken by cameras whose centers are symmetrical with respect to the scene k symmetry plane, the epipolar lines are images of symmetry lines, and reverseb symmetry lines project into epipolar lines.\nSymmetry lines are 3-D lines perpendicular to the symmetry plane. With the notations defined above (see figure\nI), for any world point X, the lines X?i and C c are parallel by construction. It follows that the epipolar plane con-\ntaining a point X also contains the symmetric point ?i, and consequently the corresponding symmetry line Xi. In other words, all symmetry lines lie in an epipolar plane. It results that the epipolar line defined by the epipolar plane in each image is also the projection of all symmetry lines contained in this plane. Reversely, any symmetry line projects into the epipolar line defined by the epipolar plane containing the symmetry line. Q.E.D.",
+ "4. Mirror-stereo theorem\nPer Lemma 2, the symmetry lines in a single perspective view of a mirror symmetric scene, taken by an arbitrary projective camera, are also the epipolar lines of the stereo pair consisting of the given image and the image formed by any projective camera located symmetrically, and thus completely characterize the epipolar geometry between such a view and the original view. Per Lemma 1, one such view, specifically the one taken by the virtual camera symmetrical to the real one with respect to the scene's symmetry plane, is actually the same image as the original. In those two (identical) images, the image points of a world point and its (world) symmetrical point are reversed. It results that the original image is geometrically equivalent to two views from two different positions, related by a computable epipolar geometry. Q.E.D.\nGiven the epipolar pencil and a set of point correspondences in the one real image, it is possible, using classical epipolar geometry results, to compute the fundamental matrix relating the two views, the camera matrices (up to a projective transformation), and for each point correspondence, the 3-D point that projects to those points (up to a projective transformation). Note that additional constraints derived from the mirror symmetry property can be used to make those computations simpler than in the general case, as computations can be done in a single image.\n5. Application\nWe developed our novel formulation to use existing 2- view stereo tools to perform 3-D reconstruction of mirror symmetric objects from a single, real perspective image. Such systems take as input two images, taken by the same physical camera from different positions, and sometimes require the images to be rectified. If the rectification poses no theoretical problem given the availability of epipolar pencils, the synthesis of a virtual symmetric view taken by a physical camera requires more work. We show how to build such an image in the case of a calibrated pinhole camera, in order to allow Euclidean reconstruction of the scene. We then present one example of the results obtained by processing image pairs made of one real perspective image of a mirror symmetric object, and one synthetic symmetric view, in an off-the-shelf commercial package, Eos Systems' PhotoModeler Pro 4.0 [SI.\n5.1. Calibrated pinhole camera case Suppose the camera used to take the available picture is a pinhole camera. It projects the world point into the image point according to the formula:\nx = K R [ / I ( - c ) ] X\nThe 3x3 matrix K is the camera calibration matrix. R is the 3x3 transform matrix from the world coordinate system to the camera coordinate system, in this case a rota-\ntion, defined by R = e T eT eT , where ( e l , e2, e 3 ) is\nthe orthonormal basis of the Euclidean coordinate system associated with the camera.\nLet (el ' , e2', e 3 ' ) be the orthonormal basis of the\nEuclidean coordinate system associated with the virtual\nsymmetrical camera. By construction, e.' = e - = Z e - . Because of the symmetry, this coordinate system's orientation is reversed compared to that of ( e l , e2, e 3 ) (i.e. if one\nis right-handed, the other is left-handed). The virtual camera projects the world point X into the\nimage point x' according to:\n[ I 2 J T\n- J J J\nThe image point of the same world point seen by the\nand with principal axis direc- physical camera placed in\ntion e3 IS: - T .\nx\" = KR\"[/J-F] .Y\nand (e, \", e2\") is an orthonormal basis of the principal\nplane such that (el\", e2\", e 3 ) has the same orientation as\n( e l , e2, e 3 ) (both are either right or left-handed). Such a\nbasis is obtained by applying an arbitrary rotation to the\nbasis (e l , e 2 ) in the plane it defines, and inverting the\ndirection of one of the axes. The rotation of the coordinate system corresponds to a rotation of the physical camera around its optical axis. The simplest analytic form naturally corresponds to no rotation, i.e. to the cases where the real camera coordinate system axes are aligned with that of the virtual (symmetric) ones, the direction of one of the axes being reversed to preserve the coordinate system's orientation. The two corresponding cases are shown in figure 2. For sake of clarity and simplicity, without loss of generality, we only consider an inversion of the x-axis. It follows that if the camera is calibrated, then the symmetric view of the virtual stereo pair can be obtained by simply performing a horizontal mirror of the original image with respect to a vertical axis going through the principal point.\n-\n- -"
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+ "image_filename": "designv11_6_0003384_s0022-0728(83)80266-6-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003384_s0022-0728(83)80266-6-Figure4-1.png",
+ "caption": "Fig. 4. Cyclic voltammogram of ferricytochrome c at a MVM gold electrode. Electrode area = 0.25 cm 2, potential scan rate = 10 mV s i. (A) 42.5 ffM ferricytochrome c in 0.1 M phosphate buffer, 0.1 M NaC1, pH 7.0; (B) electrolyte alone.",
+ "texts": [
+ " This slow electrode charging behavior observed in the metalloprotein studies is suggestive of a more involved reaction occurring at the electrode interface, than that taking place in the ferri/ferrocyanide direct electron-transfer events. Cyclic voltammetry studies of myoglobin and cytochrome c in quiescent solutions were also conducted in an attempt to characterize further the charge-transfer mechanisms of these two metalloproteins at MVM gold surfaces. Cyclic voltammograms of oxidized myoglobin samples at various potential scan rates yielded nondescript current responses. Ferricytochrome c, on the other hand, exhibited a scanrate-dependent cathodic peak. No apparent oxidation peak was observed on scan reversal (see Fig. 4). The magnitude of the cathodic peak current was directly proportional to the square root of scan rate for potential sweep rates no faster than 50 mV s -~. Upon completion of the CV experiments, the electrodes were rinsed in distilled water and then immersed in a phosphate buffer/NaC1 solution. Figure 5 shows a representative cyclic voltammogram obtained under these conditions. The ap- pearance of a voltammetric response at ca. 0.35 V was reproducible in both the myoglobin and cytochrome c experiments"
+ ],
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+ "image_filename": "designv11_6_0001941_eurbot.1997.633569-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001941_eurbot.1997.633569-Figure2-1.png",
+ "caption": "Figure 2: VIPER",
+ "texts": [
+ " 2 The mobile robots As test vehicle for the Stewart platform we use different autonomous mobile robots which have been build at our institute or in cooperation with industrial partners. All include a very efficient navigation system which allows orientation in complex, dynamic surroundings. The sensor system of each vehicle includes a laser scanner for position detection, a ring of ultrasonic sensors for collision avoidance and a camera for object recognition. Two of the mobile robots are presented in detail in this paper as they are of particularly interest for our applications: MORTIMERl (see figure 1) and VIPER2 (see figure 2). 2.1 MORTIMER MORTIMER has an octagonal shape with a diameter of 720\". The height of the loading platform is 450\" and the height of the control tower is 1150\". The robot has been developed and built in 'Mobile robot for transport and indoor room service in 'Four wheeled vehicle of the Institute for Real-Time hotels Computer Systems and Robotics 0-8186-8174-8/97 $10.00 0 1997 IEEE cooperation with a hotel in Karlsruhe where it will be used for transport of luggage and room service. MORTIMER is based on a two wheel kinematic which is explained in detail in [JLC92] "
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+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure8-1.png",
+ "caption": "Fig. 8. Cross-section of an involute worm.",
+ "texts": [
+ " (21) and determination of initial set P 0 of parameters, the computations are based on Newton\u00b1Raphson method and computerized [3]. Determination of functions (22) enables to accomplish the process of simulation of meshing of misaligned gear drive. It becomes possible to obtain [7]: (i) The path of contact on R2 determined as r2 ut /w ;wh /w : 26 (ii) Function of transmission errors determined as D/2 /w /2 /w \u00ff Nw N2 /w: 27 The term ``involute'' means that the hob is provided with an involute screw surface (Fig. 8). Such a surface may be traced out by a straight line performing a screw motion and being tangent to the helix on base cylinder. Hob surfaces R i h i I; II) and the unit normals to R i h are represented for both sides I and II of the thread by the following equations: r i h u i h ; h i h r i bh sin h i oh h i h u i h cos k i bh cos h i oh h i h \u00ffr i bh cos h i oh h i h \u00ff u i h cos k i bh sin h i oh h i h u i h sin k i bh phh i h 266664 377775 i I; II ; 28 n i h h i h N i h N i h sin k i bh cos h i oh h i h sin k i bh sin h i oh h i h cos k i bh 266664 377775 i I; II ; 29 where h i oh p 2N1 \u00ff inv a i o : 30 In both cases the upper and the lower signs refer to surface sides I and II, respectively"
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+ "image_filename": "designv11_6_0003001_10402008908981893-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003001_10402008908981893-Figure1-1.png",
+ "caption": "Fig. 1-Nomenclature for rolling bearing thermal study",
+ "texts": [],
+ "surrounding_texts": [
+ "Estimate of Surface Temperatures During Rolling Contact@\nJ. W. KANNEL and S. A. BARBER (Member, STLE) Battelle Columbus Division\nColumbus. Ohio 4320 1-2693\nTetnperature has been shown to be a key factor i n the peformance\nof rolling and sliding contacb. I n normal bearing operation, contact areas 071 the bearing ball (or roller) and race are briefly heated due\nto ball or roller slip then cooled from convection to the surrounding medium. After numerous repetitive heating and cooling cycles, the bearing elemenb attain a steady state temperature that is dependent upon the heat input and the surrounding convective conditions.\nThis paper examines the temperature profile i n a rolling element using two approaches. The first approach involves a discrete stepby-step computation of the heating and cooling that occurs during a. typical cycle under various conditions of heat input and convectiot~\nconditions. Steady-state conditions are predicted by extending this repetitive process over many cycles. The second approach assumes that the heating and cooling occurs over the entire ball or roller\ntrack area after steady state is achieved. The resulb of both approaches are compared.\nPresented at the 43rd Annual Meeting In Cleveland, Ohio\nMay 9-1 2, 1988 Final manuscript approved January 11, 1988\na = Half length o f Hertz conlac1 (axial direction) A = Constant A, = Contact area A, = Circumferential surface area b = Half' width of contact (rolling direction) c = specific heat D = Friction Force 5; = Elliptical integral h, = surface heat-transfer coefficient\n7\nHeat = Ball race heating k = Diffusivity (Wpc) K = Conductivity L = Ball-race load\nThe tmhnique was used to exatnine probable temperatures i n a liquid hrbricated, liquid-cooled turbine engine bearing and in a hypothetical solid-lubricated, air-cooled turbine engrne bearing.\nINTRODUCTION\nTemperature has been shown to be a key factor in galling o r scuffing of critical machine elements. Presumably when the temperature at an interface, such as between meshing gear teeth, reaches a critical level, a boundary lubricant fill11 thermally degrades and surface transfer occurs from one tooth to the other. Leech and Kelley's ( I ) development of the critical temperature theory was based on Blok's (2) flash temperature equation. In essence, flash temperature implies the rise in temperature from a single mesh of the gears. I n many instances, however, temperature increases over a finite time interval and eventually this temperature reaches a level where surface damage can occur.\nT h e problem d u e to gradual temperature rise can occur in many components such as poorly lubricated and/or cooled ball o r roller bearings. T h e problem can also occur with traction drives o r even with high-pressure spool valves where repeated sliding motions can generate high frictional heat-\nM = Ball spin moment n = rotational speed\nrR = ball or roller radius s = Laplace transform variable t = time V = velocity x = coordinate variable y = coordinate variable - y = y / d G\na = h ~ d G p = density p = coefficient of friction WR = angular velocity\nD ow\nnl oa\nde d\nby [\nN ew\nY or\nk U\nni ve\nrs ity\n] at\n0 3:\n39 0\n9 Fe\nbr ua\nry 2\n01 5",
+ "306 J . W . K A N N E L and S. A. BARBER\nk g . 'l'lic purpose of this paper is to develop a simple model l i ~ r accumulative temperature rise in a tribological system. Co~~ccntratccl ontact temperature analyses have been pursuccl by a few researchers (3)-(8) including a recent work I)y Kasliicl :uicl Scrieg (8). T h e research has usually been focusccl on the computation of temperature for a single contacl. 'l'l~cse single contact analyses are very complicated 11111 have proclucecl some interesting temperature predictiot~s Ibr rolling contact, especially lubricated rolling contact, situations.\n'I'ltc thcory presented herein is based on classical thermal :~n;~lyscs techniques is an extension of the theory used to ~wocli~ce Blok's Ilash temperature theory. The model consists ol' a one-climensional tr:unsient heat flow analysis. In the case ol' a rollcr o r ball in a bearing, the model is used to track t lie temperature of a point on the surface of the roller o r I ~ c a r i ~ ~ g ball. 'The point is heated as it passes through the r;tcc contact. After contact, the point is cooled by conduction ittto the rollcr ancl convection at the surface. After a revolution (or a half revolution if both inner and outer races arc consiclcrecl) the point is reheated in the contact region. - I his process of heating and cooling can continue for a periocl ol'timc. Under these conditions of heating and cooling, tltc corttact surlitcc eventually reaches a steady-state tem1)c\";ttiwc clclinecl by the convective heat transfer conditions ;IIICI the licat i t~pu t .\n'l'llc 1);11)cr clcscc'-)es two approaches for surface tempera t i ~ r c cotnl)utations Ibr a bearing I~all o r roller. T h e first :11)l)ro;tc11 ir~volvcs a step-by-step computation of heating ;t t tc l cooling. 'fhe seconcl approach involves the use of an :tssurnl)tion that the contact zone heating occurs over the c t~t i rc roller circuml'ercnce. This assumption appears to be rc ;~so~~al) lc lijr computing long-term temperature rise.\nT h e boundary and initial conditions will be\nT(y,O) = 0 T(a , t ) = 0 and\naT K - = - Q + h , T a t y = O\na y\nwhere:\nQ is the frictional heating Q = Q(t) h, is the heat transfer coefficient (assumed to be constant\naround the circumference).\nLaplace Transforms\nT h e Laplace transforms for Eqs. [ I ] and [2] can be written\nand\nwhere:\nANALYSIS FOR SURFACE TEMPERATURES\nBasic Equation\n'I'lic I);tsic system to be analyzed is shown in Fig. I. A point on the rollcr surl'nce will be in contact with the inner rittg over ;I cIist;~~~cc of 2b. T h e point will be out of inner ring contact over a span of appl-oximately 2.rrrK. During contact the point will be heated by slippage between roller ;IIICI r;tce. 1;igilrc 1 coillcl also represent an angular contact I ~ c a r i ~ ~ g ill which heating would be due to ball spin and slip. For tile analysis it will be assumed that the roller can be trcatccl as a semi-infinite half space with surface heating :~t~cl/or cooling. 'flrc heat transler equation can be written (scc I;igilrc 2)\nr . 1 is tcml~cr-aturc t is time K is t1icrm:tl concluctivity p is clc~rsity c is sl~ecilic heat\n8 is the transform of T q is the transform of Q.\nSolution to Transformed Equation\nT h e solution of Eq. [3] can be written\n0 = A e x p (- Ey)\nD ow\nnl oa\nde d\nby [\nN ew\nY or\nk U\nni ve\nrs ity\n] at\n0 3:\n39 0\n9 Fe\nbr ua\nry 2\n01 5",
+ "Estimate of Surface Temperatures During Rolling Contact 307\nUsing Eq. [4]\n- - A = - q + h,A [GI h, rn h: (t - t') ATi = Q [ erfc exp Kpc hs . [I 11\nT h e transformed surface temperature then is\nInversion of Eq. [8]\nEq. [8] can be written\nwhere:\n' Q dt ' ~ = l , ~ ~ - a [ Q e \" P\n[as(t- t')] erfc ( a m) dt'\nwhere\nNote Eq. [I I] can be solved for numerous time steps where\n[71 Q is different at each step. For example, during contact ti < t' < (ti + At), Q could\nbe a large number. Conversely, during no contact (ti + At) < t < ti+ 1 , Q could be zero. For this situation\nwhere:\nD is the friction force\n[91 V is surface velocity A, is contact area\nIf Q is assumed to be spread out over the entire circumference (call this heating QA) rather than just the contact zone\nQA = DVIA, for all time. [ 131\nHere A, is the circumferential surface area. Equation [I I ] can be solved for a given time interval to yield\nas t - (large 11,)\nIf Q is a constant over some time increment, such as ti to ti Temperatures computed, using Eqs. [I I], [I41 and [I51 + At, then the temperature rise over that increment, ATi, for the conditions given in Table I , are given in Table 2. can be written There is reasonable agreement between the temperature\nD ow\nnl oa\nde d\nby [\nN ew\nY or\nk U\nni ve\nrs ity\n] at\n0 3:\n39 0\n9 Fe\nbr ua\nry 2\n01 5"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002606_iros.1997.655141-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002606_iros.1997.655141-Figure1-1.png",
+ "caption": "Figure 1: Coordinate systems definitions",
+ "texts": [
+ " So, L estimation might be (7) R1 3 L = ( o 1 ) According to the figure 2, it is obvious that AX = X 3 (8) (3) 0 T : homogeneous transformation matrix from Fm where A and B are known and X represents the handeye calibration transformation that is to be estimated. t.o Fm - I ' _ _ At least three different robot motions are necessary to solve the system [3]. In practice, a set of n positions ( n 2 3) is selected and the system is overdetermined. T represents the location of the calibration object in the robot world coordinate sytem. There is a lot of possibilities to solve for (AiX = X B i ) i E [l..n] (9) (4) Rt Tt T = ( 0 1 ) 0 X : homogeneous transformation matrix from Fe to Fh is the unknown hand-eye transformation. (5) Figure 1 explains the relationships between the different frames and the various homogeneous matrices. 2.2 Classical Approach Let's consider two different positions i and j of the gripper inside the robot workspace (see fig.2). Then, matrices H and L have to be indexed by i and j corresponding to these two different stations of the gripper. Matrix X doesn't have any index since the camera is rigidly mounted on one of the robot links. As H, and H j are known, it is possible to estimate the transformation A that gives the location of the second gripper position relative to the first position"
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+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure1-1.png",
+ "caption": "Fig. 1. Face worm-gear drive.",
+ "texts": [
+ " . . ; 5) fij 0 equation of meshing during the process of generation of worm (i w; j c), hob (i h; j t) and worm-gear (i 2; j h) F2h 0 equation of singularities * Corresponding author. Tel.: +1-312-996-2866; fax: +1-312-413-0447. E-mail address: \u00afitvin@uic.edu (F.L. Litvin). 0045-7825/00/$ - see front matter \u00d3 2000 Elsevier Science S.A. All rights reserved. PII: S 0 0 4 5 - 7 8 2 5 ( 9 9 ) 0 0 3 2 9 - 1 A face worm-gear drive is formed by a worm and a worm-gear with a special location of teeth (Fig. 1) that is di erent from the location of teeth of a conventional worm-gear. In addition to the term ``face worm-gear drive'' there are two other terms applied in the literature: (i) helicon gear drive, related with the patent and invention proposed by Saari [10], and (ii) hybrid gear drive, related with the patent and invention proposed by Litvin et al. [9]. Saari's invention was proposed as a gear drive alternative for a hypoid drive. The helicon gear drive is designated for transformation of rotation between crossed axes and is provided with the following features: (1) The worm is of Archimedes' type (with straight axial pro\u00aele of thread)"
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+ "image_filename": "designv11_6_0001811_s0956-5663(98)00010-4-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001811_s0956-5663(98)00010-4-Figure1-1.png",
+ "caption": "Fig. 1. Construction of the ring electrode. Illustrations of (a) and (b) are the side view and the surface of the electrode, respectively. 1: copper covered wire, 0.5 mm diameter; 2: polyolefin heat shrinkable material tube; 3: copper bare wire, 0.05 mm diameter; 4: carbon paste; 5: TTF-TCNQ carbon paste mixture. (c) A microscope photograph of the TTF-TCNQ band on the ring electrode surface.",
+ "texts": [
+ " After mixing the two solutions, the mixture was kept with stirring at room temperature to be cooled down overnight. The mixture was filtered to collect black crystals under vacuum. The crystals were then washed with 5 ml acetonitrile followed by diethyl ether until the wash became colorless. The crystals obtained were dried under vacuum at room temperature to give | 1.6 g of fine black crystals. Details of this procedure can be found elsewhere (Bartlett, 1990). The structure of a ring electrode of diameter approximately 1.5 mm, and a band width of 10\u201320 mm is illustrated in Fig. 1. The method of \u2018fabrication\u2019 was crude and adopted with the intent of an initial investigation of the possible improvement in the signal/noise ratio which could be achieved through the use of a \u2018band\u2019 electrode. Such electrodes show intermediate behavior between spherical and linear diffusion. As far as the fabication of such an electrode is concerned, the dimensions are more important than the preparation method which is reported here and a more sophisticated development is recommended for further work",
+ " The tip of the rod, where the carbon paste had been packed, was then sliced making a new surface of a ring electrode. Finally, excess carbon paste was removed by wiping with a piece of clean paper and TTFTCNQ carbon paste, which had been prepared by mixing 50 mg of TTF-TCNQ salt, and 50 mg of graphite carbon powder and 50 mg of silicon oil were packed on the band of the ring electrode by smearing on a glass slide. The excess TTF-TCNQ carbon paste was also removed by wiping with a piece of clean paper. The electrode surface is shown in Fig. 1(c). The TTF- TCNQ band width of the ring electrode is 10\u201320 mm and therefore the surface area is | 0.10\u20130.19 mm2. The electrode is reusable, when the surface is renewed by slicing. In the case of preparing a lactulose sensor, FDH and b-gal were dissolved with 50 mM citrate buffer solution (pH 4.5) to make the concentrations 90 mU/ml and 600 mU/ml, respectively. 10 mL of the enzyme solution was dropped on the surface of the TTF-TCNQ ring electrode, and then the electrode surface was covered with a dialysis membrane and was secured with a rubber Oring"
+ ],
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+ "image_filename": "designv11_6_0003477_cnm.913-Figure20-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure20-1.png",
+ "caption": "Figure 20. Further decomposition of factors DC and CD (subspaces V (51) and V (52)): (a) DDC and DCD ; and (b) EDC and ECD .",
+ "texts": [
+ " The factors of this structure are shown in Figure 19. It can be observed that the factors resulted by both group-theoretical and algebraic method, are identical. Considering the factor of the subspace V (51) and its graph model, as shown in Figure 19(d), it can be seen that this factor has a vertical plan of symmetry, which suggests the point group C1v . In the other words, this factor is of canonical form III symmetry and can be further decomposed. The result of decomposition of this factor is shown in Figure 20. Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm As it is seen, factors DDC and DCD are exactly the same as factors DCC and DDD , shown in Figure 19(b), and do not have to be solved. Thus, instead of solving a problem with 16 DOFs only a number of small problems are being solved: a one-dimensional problem and three problems of dimension three. This can some how highlight the efficiency of the proposed method. The procedure introduced in this paper consists of forming the graph model of a mass\u2013spring system, recognizing the symmetry operators and symmetry group of the graph, selecting the positional functions of the nodes of the graph as the basis vectors of the vector space of the problem"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002913_tmag.2003.810552-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002913_tmag.2003.810552-Figure1-1.png",
+ "caption": "Fig. 1. Magnetic field inside the induction machine for rotor position = 20 .",
+ "texts": [
+ " This comparison allows us to estimate the influence of rotor slot wedges on the stator current harmonic content and stator vibration spectrum. During steady-state operation, all electromagnetic and mechanical phenomena occur at various fixed frequencies. It is therefore possible to perform a frequency domain analysis based upon a set of samples taken from the time domain and computed using a transient finite element analysis. For every time step of the transient analysis, the instantaneous magnetic field is used to postprocess the reluctance forces acting on the stator teeth. Fig. 1 shows the flux pattern for one pole of the four-pole induction machine for a certain rotor position. Fig. 2 shows the corresponding reluctance forces acting on the entire stator. The magnetic forces (both Lorentz forces and reluctance forces) are obtained using [4]: (1) where represents the magnetic energy and represents the displacement or deformation. The deformation is considered in 0018-9464/03$17.00 \u00a9 2003 IEEE the entire model. represents the magnetic finite element system: is magnetic stiffness matrix, is the vector of nodal values of magnetic vector potential, and is the source term representing the current excitation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000497_a:1008966218715-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000497_a:1008966218715-Figure7-1.png",
+ "caption": "Figure 7. Example of associated case.",
+ "texts": [
+ " The difference between the orientations of the major axes of Ri and Mk is smaller than some uncertainty bound 2. The mean vector mi of Ri is located within the distance \u03bb\u03042k from the major axis of Mk 3. Ri is located within the distance \u03bb\u03041k from the mean vector m\u0304k of Mk Condition (1) checks if the angle difference between the major axes of Mk and Ri is sufficiently small. If the difference is larger than the uncertainty bound \u03c3\u03b8 , then some obstacles that used to be in Mk may have been moved outside of Mk . \u03c3\u03b8 here is defined as \u03c3\u03b8 = tan\u22121 \u03bb\u03042k \u03bb\u03041k . As shown in Fig. 7, \u03c3\u03b8 represent the upper limit of the angle variation of the major axis of Mk assuming that the obstacles are fixed. Condition (1) is then equivalent to |\u03b8\u0304k\u2212\u03b8i | < \u03c3\u03b8 . Condition (2) checks whether Mk and Ri are closely located by examining the distance from the mean position of Ri to the major axis of Mk . Once the condition (1) is satisfied and if the distance is smaller than \u03bb\u03042k , then Mk and Ri are aligned and closely located with each other. If we define m\u0304k as the mean vector of Mk and \u03c6\u0304k as (cos \u03b8\u0304k, sin \u03b8\u0304k), then any point p on the major axis of Mk can be formulated as \u03c6\u0304k \u00b7Q1 \u00b7 (p\u2212 m\u0304k) T = 0, where Q1 = [ 0 \u22121 1 0 ] ",
+ " The distance di from the major axis of Mk to the mean vector mi of Ri is then computed as di = |\u03c6\u0304k \u00b7Q1 \u00b7\u2206mT |, where \u2206m = mi \u2212 m\u0304k . Condition (2) is then equivalent to di < \u03bb\u03042k , where the minor eigenvalue \u03bb\u03042k is used as an uncertainty bound of Mk along the direction of its minor eigenvector. On the other hand, condition (3) checks whether the associated Ri is roughly overlapped with Mk . It is then equivalent to |\u03c6\u0304k \u00b71mT | < \u03bb\u03041k + \u03bb1i where |\u03c6\u0304k \u00b71mT | is the projection if1mT on the major axis of Mk and \u03bb\u03041k is used here as an uncertainty bound of Mk along the direction of its major eigenvector. As shown in Fig. 7, if conditions (1), (2) and (3) hold, then Ri is associated with Mk and vice versa. Now, condition (3) is further divided according to whether the obstacles in Mk are fixed or moved. If all of the obstacles are static and fixed, then |\u03c6\u0304k \u00b71mT | will be close to zero and the obstacles previously identified as Mk may be detected again as Ri with small disturbances in its parameters. However, if the obstacles in Mk is moved to another location or some obstacles are added to Mk or subtracted from it, then the parameters of Mk are changed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001341_s1359-6462(98)00437-0-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001341_s1359-6462(98)00437-0-Figure1-1.png",
+ "caption": "Figure 1. Illustration of the geometrical relationships between specimen, and incident & beams for measurements of the (a) tensile extension and (b) Poisson contraction.",
+ "texts": [
+ "17\u00b0 on the incident and diffracted beams respectively. Square-sectioned 5 by 5mm testpieces of gauge length 70mm were used for the in-situ neutron diffraction studies. These were machined from Waspaloy stock material, the chemical composition of which is given in Table 1. A servo-hydraulic universal testing system was used with the samples orientated such that the scattering vector lay either along the direction of the load or perpendicular to it, thus allowing measurements of either the tensile extension or the Poisson contraction, see Figure 1. The whole of the gauge length of the specimens was immersed in the neutron beam so that the counting statistics were optimised. Additionally, an extensometer was attached to the sample, which permitted measurement of the total engineering strain accumulated and hence also the determination of the true stress at each load. For the measurements in the longitudinal direction, the nominal stress on the sample was increased in ;100 MPa increments to 1000 MPa before unloading; further load cycles were applied subsequently which had a peak nominal stress of 1200 MPa"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002731_j.ijmachtools.2004.03.005-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002731_j.ijmachtools.2004.03.005-Figure8-1.png",
+ "caption": "Fig. 8. Contact between angle with probe; (c) surface normal n perpendicular to probe; (d) rigid force feedback; and (e) soft force feedback.",
+ "texts": [
+ " When a collision is detected between the part and the stylus or the body, a force is fed back to the user via the haptic device and an alarm is sent to the user visually. When only collision between the probe tip and the part occurs the coordinates of the tip is recorded and a force is feedback to the user. In order to have a more realistic force feedback, a mechanics model is proposed. When a probe tip comes into contact with a part, the direction and the magnitude of collision force depend on the probe contact angle h between the probe and the normal of touched surface of the part as shown in Fig. 8. Different contact angle h gives a different felt force as the elasticity of the stylus is different in different directions. The following equations provide an estimate about the difference in spring constant in two extreme conditions as shown in Fig. 8(a),(c). In the case of Fig. 8(a), the displacement d can be calculated as d \u00bc FL EA F \u00bc kad where ka \u00bc EA=L, E is the modulus of elasticity, L is the length of the stylus and ka is the spring constant. And in Fig. 8(c), the displacement d is calculated by d \u00bc 5FL3 48EAr2 or F \u00bc kpd where kp \u00bc \u00f048EA=5L\u00deC2 and C \u00bc r=L, r is the radius of the stylus and kp is the spring constant. Based on the above equations, for a typical stylus of r \u00bc 2 mm and L \u00bc 100 mm, C \u00bc 2=100 \u00bc 0:02, the ratio between the two spring constants ka and kp is about 260. That is, the spring constant of ka is normally much bigger than kp. So, different forces could be felt by the user when the contact angle h is different. When ka is used, the felt force is instant and big as shown in Fig. 8(d) while kp gives a much smaller contact force. There is a transition in-between ka and kp. The duration of the transition is dependent on the contact angle hi as shown in Fig. 8(e). When collisions as shown in Fig. 5(b)\u2013(d) occur, a crispy force corresponding to a solid collision is output. This force indicates that the contact is invalid, and the stylus must be repositioned to select a surface point so that only the stylus tip is in contact with an object. The above mechanics model provides a kind of fidelity as if the user is operating on a real CMM. Measuring points are selected according to the tolerance type and its requirement and the shape and size of the part. Taking the measurement of the parallelism between planes A and B of a flange shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001277_s0997-7538(00)00139-x-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001277_s0997-7538(00)00139-x-Figure2-1.png",
+ "caption": "Figure 2. Fluid-film linear model.",
+ "texts": [
+ " (20) The dimensionless dynamic transmissibility, which compares the hydrodynamic force generated during nonlinear transient motion to the force due solely to unbalance, is important in the kind of this investigation. In equation form this is written as FD = \u221a F 2 x + F 2 y Meb\u03c92 . (21) Under the assumption of small displacements of the journal centre, the fluid-film force components in the vertical and horizontal directions, Fx and Fy , may be linearized around the static equilibrium position Oj0 (figure 2) to obtain: { Fx = Fx0 + axxx + axyy + bxxx\u0307 + bxyy\u0307, Fy = Fy0 + ayxx + ayyy + byxx\u0307 + byyy\u0307, (22) where Fx0 and Fy0 are the fluid-film force components under the static conditions, and aij and bij the stiffness and damping coefficients expressed as: aij =\u2212 ( \u2202Fi \u2202xj ) Oj0 , bij =\u2212 ( \u2202Fi \u2202x\u0307j ) Oj0 , (i, j)= (x, y). (23) At the threshold of instability (Lund, 1986), the dimensionless critical mass Mc and the corresponding whirl frequency ratio \u03b3c are expressed as: Mc = As \u03b3 2 c , (24) \u03b3 2 c = ( \u03bdc \u03c9 )2 = (Axx \u2212As)(Ayy \u2212As)AxyAyx BxxByy \u2212BxyByx , (25) where: As = AxxByy +AyyBxx \u2212AxyByx \u2212AyxBxy Bxx +Byy , Aij = aij C W0 , Bij = bij C\u03c9 W0 , (i, j)= (x, y) and Mc = McC\u03c9 2 W0 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002874_j.aca.2005.02.040-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002874_j.aca.2005.02.040-Figure2-1.png",
+ "caption": "Fig. 2. The structures of hydrochlorothiazide (a) and furosemide (b).",
+ "texts": [
+ " In athletic sports, because diuretic could increase urine flow, some athletes utilize it to achieve two aims shown as blow: one is diluting the urine to conceal the other doping agents; another is reducing the body weight at short notice to participate in the lower weight category. Since 1988, diuretic has been banned by the Medical Commission of the International Olympic Committee [7,8]. Hydrochlorothiazide (6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulphonamide-1,1-dioxide) and furosemide (5-(aminosulfonyl)-4-chloro-2-[(2-furanyl-methyl)amino]benzoic acid) are two representative diuretics, and their structures are shown in Fig. 2. Some methods based on various analytical techniques have been reported for the determination of the two diuretics, such as coulometric titration [9], electrochemical detection [10,11], spectrophotometry [12\u201315], fluorescent detection [16], electrogener- 003-2670/$ \u2013 see front matter \u00a9 2005 Elsevier B.V. All rights reserved. oi:10.1016/j.aca.2005.02.040 ated chemiluminescence detection [17] and chemiluminescence detection [8,18]. In this paper, it was found that both hydrochlorothiazide and furosemide could enhance the chemiluminescence emission intensity of RuBPS\u2013Ce(IV) system"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.28-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.28-1.png",
+ "caption": "Figure 4.28. The gear train geometry.",
+ "texts": [
+ " However, since the reference frames are fixed in the ge:ars, their material points have no motion relative to these frames. Hence, the basic equations (4.46) and (4.48) reduce for each gear to the rigid body formulas (2.27) and (2.30) referred to frames whose angular velocities in the machine frame are ID 10 , ID 20 , and ro 30 , as noted before. Thus, for the point Ron the fixed gear A, the contact point at R on C must satisfy V R = V c + ID20 X r = 0, (4.85b) in which r is the position vector of R from C, as shown in Fig. 4.28. Of course, point C belongs also to the extension of the power gear B for which v B = 0; hence, with r = -q, as shown, we find with ( 4.85b) the absolute velocity of point C: Vc = ro 20 X Q = ro 10 X b, (4.85c) 292 Chapter 4 in which q is the position vector of Q from C and b is the position vector of C from B. Use of (4.85a) in (4.85c) yields (1)21 X q = ro 10 X (b- q). (4.85d) Using the geometry of Fig. 4.28 and the rule (4.84), we find from (4.85d) the relative angular velocity component W 21 = -w[sin 8 + (b/q) sin (r/J + 8)] = -w(sin 8 +cot r/J cos 8). But the last term may be written as the ratio cos(\u00a2>- 8)/sin \u00a2>; hence, with the use of ( 4.84 ), the angular velocity of the epicyclic gear C relative to the power gear B may be expressed as . sin 38. ro21 = w2Ilz = -w cos 281z. (4.85e) Part (b). The total angular velocity of the epicyclic gear in the machine frame may be derived by substitution of (4",
+ "85e), we obtain the angular acceleration of the epicyclic gear in the machine frame, but referred to the power gear frame 1: \u2022 2 sin 38 cos 8 . Olzo = -w cos 28 \u20223\u00b7 (4.86b) Motion Referred to a Moving Reference Frame and Relative Motion 293 The reader also may confirm this result by differentiation of ( 4.86a ). Part (c). It remains to determine the angular velocity of the output gear D. Since the rolling contact point Q belongs to both C and D, and v D = 0, we have V Q = (!) 30 X X = V C + (!) 20 X q, (4.87a) wherein x is the position vector of Q from D, as shown in Fig. 4.28. Therefore, use of (4.85c) in (4.87a) yields ID 30 X X= 2ID20 X q = 2ID 10 X b. (4.87b) Q = 2w(b/d) sin(Q? +e). (4.87c) Further, with the aid of the rule ( 4.84) and the triangle relations b/c =cot tP and c/sin tP = djsin e, it follows from ( 4.87c) that the angular speed of the out put gear Dis Q = 4w cos2 e. (4.87d) This completes the solution of the problem. It may be seen from ( 4.84) that 0 < e < n/4. It thus follows from ( 4.87d) that the ratio of the output angular speed to the input angular speed decreases with increasing e so that QjwE (4, 2); and according to (4"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002410_1475921703036049-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002410_1475921703036049-Figure7-1.png",
+ "caption": "Figure 7 The AMRL gear test rig.",
+ "texts": [
+ " It is worthwhile to notice that, in cases where the structural resonant frequency is not significantly separated from the major meshing harmonics (usually the 1st and 2nd meshing harmonics), the CWT could be less effective in detecting localized changes. at NIPISSING UNIVERSITY LIBRARY on October 6, 2014shm.sagepub.comDownloaded from In this section, we present the analysis results using existing data collected in a tooth-crack propagation test [29]. The test procedures were designed to simulate the natural development of gear tooth cracking. The test rig is shown in Figure 7. The test gear was the input pinion manufactured under AGMA Class 13 standard (aircraft quality). It had 27 teeth; a tooth width of 10mm, a rated power of 24.5 kW and it was operated at a constant shaft speed of 40Hz. The gear was spark-eroded at the root fillet of a tooth, across the middle of the tooth width. The eroded notch (length width depth\u00bc 2 0.1 1 mm) was designed to simulate the crack initiation. Figure 8(a) shows the SA acquired at 164% rated load and 5-h 36.8-min into a total of 8-h test, where we can easily see the dominance of gear meshing harmonics and the amplitude modulation waveform with a period of about two cycles per revolution (2nd shaft order)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.12-1.png",
+ "caption": "Figure 3.12. Schematic for Chasles' screw displacement theorem.",
+ "texts": [
+ " Let the displacement of a base point 0 and the Euler rotation of the rigid body be assigned; then the general displacement of any particle P at x from 0 is provided by (3.134a). We wish to prove that there exists a base point 0*, say, whose displacement b* is parallel to the axis of the Euler 198 Chapter 3 rotation; hence, with 0* as the base point, the result follows. Therefore, we shall need to determine the new parallel translation b* and the location r of 0* from 0. We may always write b = b\" + ba in terms of the component vectors b\" and ba normal and parallel, respectively, to the axis of rotation, as shown in Fig. 3.12. Hence, (3.134a) may be written d(P) = ba + [b\" + Tx(P) ]. (3.140) However, in accordance with the parallel axis theorem, the displacement terms consisting of a rotation about a line and a translation perpendicular to the line is equivalent to a pure rotation about a parallel axis through a base point at 0*, say. Thus, the term in the brackets in (3.140) may be replaced by the pure Euler rotation Tx*(P) to yield d(P) = b, + Tx*(P) ( 3.141 a) with bn= -Tr, (3.14lb) where r = x- x* is the position vector of 0* from 0, as shown in Fig. 3.12. But (3.141a) states that the assigned displacement d(P) is equal to the same Euler rotation about an axis at 0* and a new translation b* = b, parallel to that axis, and Chasles' theorem follows. This displacement (3.141) is recognized as a typical screw displacement, from which the theorem derives its name. The axis of the Euler rotation at 0* is called the screw axis.* The pitch of the screw, defined by p = (b \u00b7a )/8, is identified as the ratio of the screw translational displacement to the angle of rotation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002489_j.talanta.2004.06.048-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002489_j.talanta.2004.06.048-Figure4-1.png",
+ "caption": "Fig. 4. Cyclic voltammograms of platinum electrodes (\u00d8 = 5 mm): (a) bare, (b) modified with copolymer poly(pyrrole\u2013biotin, pyrrrolelactitobionamide), (c) modified with biotinylated polypyrrole in the presence of 1 mM catechol, 0.1 M LiClO4 in water (pH 7). Polymer films were electrodeposited by controlled potential electrolysis at 0.8 V (charge: 1 mC). Scan rate at 100 mV s\u22121.",
+ "texts": [
+ " In order to imobilize CT on the electrode surfaces by affinity interactions ia the formation of avidin\u2013biotin bridges, a novel biotinyated copolymer (poly(pyrrole\u2013biotin), poly(pyrrole lactoionamide)) was used as the initial anchoring layer. This ew polymerized film was designed to improve the transuction sensitivity of the enzymatic reactions based on the mperometric detection of the enzyme products at the unerlying electrode surface. Catechol was used as an elecrochemical probe to illustrate the difference of permeabilty between the biotinylated copolymer and the previously sed poly(pyrrole\u2013biotin). Fig. 4 shows a series of cyclic oltammograms collected at 100 mV s\u22121 for a bare electrode, poly(pyrrole\u2013biotin) and a copolymer modified electrodes. For the poly(pyrrole\u2013biotin) electrode, the electrochemial activity of the redox probe was markedly blocked by the resence of the polymer film. As expected, the oxidation peak ecreased drastically while the peak separation increased inicating the low permeability of poly(pyrrole\u2013biotin) film. n contrast, the copolymer appeared much more permeable ince the catechol electroactivity remained almost identical"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002056_s0379-6779(00)00450-1-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002056_s0379-6779(00)00450-1-Figure3-1.png",
+ "caption": "Fig. 3. Dependence of first oxidation peak current of PAN/PAn composite on sulfuric acid concentration.",
+ "texts": [],
+ "surrounding_texts": [
+ "Electrochemical polymerization was carried out in a simple cell chamber of 200 ml capacity using a threeelectrode system, i.e. a disc-type Pt working electrode (diameter, 1 cm) coated with 2.0 mm thick PAN \u00aelm, a plate-type Pt counter electrode (1 cm 1 cm), and an aqueous sodium chloride saturated calomel electrode (SSCE) as the reference electrode.The electrolyte solution consists of 0.1 M aniline and 0.1 M sulfuric acid in 50:50 (volume ratio) mixture of acetonitrile and water. The potential range for electrochemical polymerization and scanning rate are \u00ff0.2 to 1.0 V (versus SSCE) and 50 mV/s, respectively. Unless otherwise stated all data are for above-mentioned experimental conditions. The details of the experimental technique are reported in an earlier paper [16]."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002434_0022-4898(91)90017-z-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002434_0022-4898(91)90017-z-Figure4-1.png",
+ "caption": "FIG. 4. Forces acting on the wheel system.",
+ "texts": [
+ " Measured quantities and sensors (1) Resultant soil reaction. The resultant soil reaction and its line of action were calculated according to the following equations. The value of the contact load was corrected by subtracting the small vertical force due to the bearing friction detected by a pair of L-shaped sensors [7] in the right and left sides from the net weight of the wheel system. The magnitude F and the direction 0 of the resultant soil reaction F, and the minimum distance R from the center of the wheel to F (see Fig. 4) were 362 Y. NOHSE et al. calculated f rom the moments of the L-shaped sensors using the equations: f = V ' { ( M 2 - M1)/ l l} 2 + {(M3 - M4)//14 + W} 2 (1) 0 = COS -1 {M2 - M1)/(Fl l )} (2) R = {M1 + W ( l + l 3 + 14)}/{F - Lcos (o l - 0)} (3) where W is the net weight of the wheel system, M1, M2, M3, M4 are the moments measured by the strain gauges 1, 2, 3, and 4, respectively in the L-shaped sensors, I 1, 12, 13, 14, are the distances between the gauges and l is the horizontal distance between the position of gauge 4 and the center of gravity of the net weight of the wheel system"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002517_1.1515324-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002517_1.1515324-Figure1-1.png",
+ "caption": "Fig. 1 Biped walking mechanism",
+ "texts": [
+ " In order to compare with the human walking locomotion, human body parameters are adopted to calculate the optimal trajectory solution, and the influence of the upper body mass on a walking locomotion is discussed. Finally, in Section 4, we summarize the main results of this study. 2.1 Model of a Biped Mechanism and Walking Locomotion. As the first step to solving minimum input walking trajec- rom: http://dynamicsystems.asmedigitalcollection.asme.org/ on 01/28/201 tory by the optimal trajectory planning method, we deal with a planar biped walking mechanism which has thighs, shanks and small feet as shown in Fig. 1. We disregard the upper body because it has little effect on walking locomotion. It will be confirmed in Section 3.7. Thus, two legs are assumed to be directly connected to each other through an actuator. We assume that both knee and ankle joints can be driven by individual actuators, and the knee joint of the stance leg is passively locked by means of a stopper mechanism or an actuator to prevent the mechanism from collapsing. The ankle of the stance leg is modeled as a rotating joint fixed to the ground, while the foot of the swing leg is neglected",
+ "325 m and 0.35 m are similar to the pattern with the step length of 0.3 m as shown in Fig. 7b . Figure 21 shows the step periods t11t2 and the average speeds V\u0304 of the optimal solutions for the step length values of 0.25 ;0.35 m. We note that the period and the step length increases gently with an increase in the step length. 3.6 Forward Dynamic Simulation. One of our aims in this study is to obtain the optimal feed forward control torque at all joints for the biped walking mechanism as shown in Fig. 1 by the optimal trajectory planning method. Therefore, there remains a question whether the same motion as the trajectory solution can be generated by using the solved joint input torque. Particularly when u150, u1 shows a large undulation in Figs. 11b \u2013 d although the constraint Eq. ~21! is satisfied. It needs to be confirmed whether the same motion as Fig. 10 can be obtained by forward dynamic simulation if we put u150 and use the solutions of u2 and u3 as shown in Fig. 11. We first simulated the walking motion for the full-actuated system by using the solutions of u1 , u2 , and u3 as shown in Figs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002129_09500830210128074-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002129_09500830210128074-Figure2-1.png",
+ "caption": "Figure 2. Applying a magnetic \u00aeeld to an ordered ferro\u00afuid foam can result in a change in the structure. (a) The transition from 2\u00b11\u00b11 to 2\u00b12\u00b10 was induced by a local oscillating magnetic \u00aeeld gradient (frequency, 2 Hz; strength, 450 G mm 1). The bubbles (diameter, 6.2 mm) move upwards in the tube at a rate of 30 bubbles per minute. (b) The same oscillating \u00aeeld gradient resulted in a transition from 2\u00b11\u00b11 to bamboo. Here the bubbles (diameter, 6.2 mm) move upwards at a rate of 20 bubbles per minute. Such structural transitions can also be induced using a static permanent magnet.",
+ "texts": [],
+ "surrounding_texts": [
+ "The most primitive structure is a regular train of \u00afat \u00aelms: this is the bamboo or 1\u00b11\u00b10 structure (\u00aegure 1). Apart from this case the structures belong to a sequence of spiral arrangements with only hexagonal cells at the surface. They are indexed with the standard notation of phyllotaxis (Jean 1994), as in the nomenclature of carbon nanotubes. Examples are the structures 2\u00b11\u00b11, 2\u00b12\u00b10 and 4\u00b12\u00b12, as shown in \u00aegure 1.\nThe imposition of a local magnetic \u00aeeld by means of a small permanent magnet dramatically a\u0152ects these moving structures. The \u00aeeld can, for example, induce transitions from one structure to another or twist them through 90 or 180\u00b0. Some of these e\u0152ects are shown in \u00aegures 2 and 3 (and in digital video clips of cylindrical ferro\u00afuid foams, available at the present authors\u2019 websitey). The bubbles are very robust; we do not observe rupture of the \u00aelms that separate them, even during rapid changes of the kind shown here.\nThis use of a magnetic \u00aeeld provides precise local control over structural changes which have in the past been promoted by forced drainage (Hutzler et al. 1997, Boltenhagen and Pittet 1998) or mechanical compression\u00b1dilation (Boltenhagen et al. 1998), applied to the whole system. Moreover we have observed that the size of generated bubbles, of crucial importance in determining the cylindrical structure, may also be adjusted by a magnetic \u00aeeld.\nThe action of the magnetic \u00aeeld appears to be based on two e\u0152ects, both arising from the attraction of ferro\u00afuid to the region of maximum \u00aeeld. Firstly, the foam develops a higher liquid fraction, which is enough in itself to provoke a morphological change (Hutzler et al. 1997, Boltenhagen and Pittet 1998). Secondly, since most \u00afuid resides in the Plateau borders (the channels which are formed between bubbles in a foam of low liquid fraction), the borders are pulled towards the region of high \u00aeeld, resulting in a net torque. Together these two mechanisms o\u0152er many possibilities for propulsion and control of the bubble stream.\nThe present con\u00aeguration is vertical, but it should be possible to generate and propagate structures horizontally, again using magnetic \u00aeelds to control the liquid\ny http://www.tcd.ie/Physics/Foams/ferro.html",
+ "fraction. One may envisage networks of channels through which bubbles travel in bamboo and 2\u00b11\u00b11 structures, separating, coming together or being selectively switched at junctions by application of local magnetic \u00aeelds. Such a scenario may have implications for micro\u00afuidics, a technology of great current interest. The present technique would have considerable advantages in its ability to maintain and process localized samples by simple variations of magnetic \u00aeelds. Moreover, identical properties should be available with emulsion systems, that is a liquid\u00b1liquid foam. In either case a small sample injected into a channel as one of the bubbles will not be smeared out by Poiseuille \u00afow, which is otherwise a serious problem in micro\u00afuidics (Whitesides and Stroock 2001).\nAs an example of the kind of operation that is clearly possible at this stage see \u00aegure 4. For suitable dimensions a 2\u00b11\u00b11 stream of bubbles splits into two bamboo sequences at a bifurcation. The introduction of a twist induced by a magnetic \u00aeeld interchanges the two streams, as indicated.\nFluidic networks based on the above techniques could \u00aend applications in the area of biotechnology, where one could \u00aell individual gas bubbles (or droplets in a ferro\u00afuidic emulsion) with di\u0152erent samples or compositions. The bubbles could then be transported to their destination as part of a moving cylindrical foam structure, to be monitored by spectroscopic methods or combined with reagents by the rupturing of the thin \u00aelms that separate bubbles. The possibilities of elaboration of this methodology seem rich indeed.\nThanks are due to Jean-Claude Bacri and to Nicolas Rivier for stimulating discussions and Valerie Cabuil for providing the ferro\u00afuid.\nBacri, J.-C., Perzynski, R., Salin, D., Cabuil V., and Massart, R., 1989, J. Colloid Interface Sci., 132, 43. Boltenhagen, P., and Pittet, N., 1998, Europhys. Lett., 41, 571. Boltenhagen, P., Pittet, N., and Rivier, N., 1998, Europhys. Lett., 43, 690. Elias, F., Flament, C., Bacri, J.-C., Cardioso, O., and Graner, F., 1997, Phys. Rev. E, 56, 3310. Harris, W. F., 1970, Phil. Mag., 22, 949."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001338_0094-114x(95)00082-a-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001338_0094-114x(95)00082-a-Figure6-1.png",
+ "caption": "Fig. 6. Tip interference for elliptical cam.",
+ "texts": [
+ " the wave generator) the basic approach is that the original pitch circle of the pinion is deformed, to give the double contacts, such that the distance between the pitch points at two contacts becomes equal to the summation of pitch circle diameter of the pinion and double the center distance. Or in other words it is equal to the pitch circle diameter of the ring gear. This means that the pitch curve of pinion is a profile which has constant-difference (i.e. point to point parallel shift) to the cam ellipse. The amount of shift (a,m, see Fig. 6) depends upon the required rim thickness and the type of bearing used. MMT31/4--I 484 R. Maiti and A. K. Roy Figure 6 illustrates the condition when tip interference just exists in the case of an elliptically deformed pinion. Tip interference is avoided if the tip of the pinion tooth, which is now in contact, does not reach at T before the corresponding gear tooth tip. Or in other words, the tip interference is avoided if 0p > ?, (31) where 0p and 7 are derived as follows: Referring to Fig. 6, let the line MP be on the radius (of curvature) vector of the inner ellipse of the rim at point P of co-ordinate (x~, y~) and T on the extension of MP. Now the co-ordinate (xc, x\u00a2) of the center of curvature can be expressed as [8]: /a a - b2\\ \"1 w ) /b 2 _ a2\\ (32) where a is the semi-major axis and b is the semi-minor axis of the elliptical cam profile. The co-ordinate of the point M (x2, Y2) is expressed as: y =0 ; _ x151 x2 x~ + (Y2-Y~)/x~ (33) \\Yc - - Y l , / J Angle ~b is given by: ~b = tan-~( y2- YJ~",
+ " (35) (36) Now to calculate the angle 0p at the critical condition of tip interference r 2 must be equal to rag, i.e. O1 T (= r) must be expressed as: r = N/(x2 + rlx - A)2 ..1_ r21y. (37) The angles 0p and 08 are then calculated as: Op= cos -1 ra~ 2~r + fp (38) 0g -- cos -1 r,g + - & - fig. (39) 2Ar Now, if the internal gear is given a rotation of angle 0g the corresponding rotation of the circular pinion would have been (ZJZp)Og. The corresponding rotation ? of the elliptical pinion can be obtained from the condition that the arc length of the circle with radius equal to (a - A) and center at Oi (see Fig. 6) over the angle (Zs/Zp)Og is equal to the length of the arc on the elliptical cam Minimum tooth difference 485 from the common starting point on the cam. If the final co-ordinate on the contour of the ellipse after the rotation is (x, y), then: ~, = t a n - ' ( x _ - - ~ ) + tip. (40) Numerical calculations using the above formulae show that with rim deflection the tooth difference can be lowered to 2 avoiding tooth interference, without tooth truncation for any practical number of gear teeth for all standard pressure angles"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure7-1.png",
+ "caption": "Fig. 7. The deformation of an in\u00aenitesimal tetrahedron: (a) Lagrangian description and (b) Eulerian description.",
+ "texts": [
+ " If one does not know that [R] = [T]T in Equation (38), an iteration method can be used to obtain the six unknowns g42, g43, g51, g53, g61 and g62 that locate the system x1x2x3, as shown in Appendix A. This iteration method may not be more e cient than the direct method shown in Equations (52)\u00b1(54), but it reveals the geometric im- plication of polar decomposition and the identity [R] = [T]T. To derive the relationship of di erent stress measures, we consider an undeformed area dA with a unit outward normal N(=Nkjk) and its deformed area da with a unit outward normal n(=nkjk), as shown in Fig. 7(a). Because F= dV/dV0, dV0=dAN dx = dANk dxk, and dV= dan dy= danm dym=danmFmk dxk, we obtain F dANk danmFmk 57 It follows from Equation (3) and Fig. 7(a) that f f 1 f 2 f 3 dAN1j1 s\u03021sj1js dAN2j2 s\u03022sj2js dAN3j3 s\u03023sj3js dANrs\u0302rsjs 58a Second Piola\u00b1Kirchho stresses are measured with respect to the rigidly rotated undeformed area dANkik. Moreover, it follows from Fig. 1 that dx1j1 is deformed into l1 dx1i1\u00c3 and hence l1i1\u00c3 =Fs1js. Consequently, it follows from Equation (11) and Fig. 7(a) that f dAN1i1 S1klki1ik\u0302 dAN2i2 S2klki2ik\u0302 dAN3i3 S3klki3ik\u0302 dANrSrklkik\u0302 dANrSrkFskjs 58b Because Jaumann strains are measured with respect to the rigidly rotated undeformed area dANkik, it follows from Equation (20) and Fig. 7(a) that f dANrir J\u0302rkirik dANrJ\u0302rkik dANrJ\u0302rkTksjs 58c Next we consider the same undeformed and deformed areas as those in Fig. 7(a) but described in terms of Euler coordinates, as shown in Fig. 7(b). It follows from Equation (23) and Fig. 7(b) that f ~f 1 ~f 2 ~f 3 danrjr trsjrjs danrtrsjs 59 It follows from Equations (57), (58a)\u00b1(c) and (59) that s\u0302 S F T J\u0302 T , t 1 F F s\u0302 60 Using Equations (3), (8), (20), (42a) and (60), we obtain the following relationships: S s\u0302 F \u00ffT F F \u00ff1 t F \u00ffT, J\u0302 s\u0302 T T S U , J 1 2 J\u0302 J\u0302 T 1 2 S U U S , s 1 2 s\u0302 s\u0302 T 61 These relationships are the same as those obtained in Atluri [1]. However, the presented derivations clearly show the directions of di erent stresses. For highly \u00afexible structures undergoing large displacements and rotations but small strains, Jaumann strain measure is the most appropriate one for use because Jaumann strains are shown to be objective geometric measures de\u00aened with respect to the rigidly rotated undeformed area"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001244_rspa.1998.0297-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001244_rspa.1998.0297-Figure2-1.png",
+ "caption": "Figure 2. Solutions of the dispersion relation for \u03c32 as a function of n with increasing values of \u03b3S = 0.2267, 0.2675, 0.2687, 0.2695. \u0393 = 3 4 , \u03c6 = 1 10 , N = 5.",
+ "texts": [
+ " (a) Linear analysis The fundamental mode solutions to the variational equations (2.18 a) are of the form \u00b5(1) n = \u03bene\u03c3nt+i\u03b4(ns/N), (5.2) where \u03ben \u2208 C6 and n denotes the mode number which, due to the choice of boundary conditions, is an integer between 1 and N . The explicit form of the linear operator LE as a function of the curvature, torsion, twist and tension is given in Goriely & Tabor (1997c) and from this the dispersion relations, \u2206(\u03c3, n; \u03b3H) = 0, can be obtained in the usual way. A typical plot of them is shown in figure 2 for increasing values of \u03b3H. The neutral curve is determined from \u2206(0, n; \u03b3H) = 0, where \u2206(0, n; \u03b3H) = (\u0393 \u2212 1)(\u0393 \u2212 2)\u03c42 F + 2\u0393 (\u0393 \u2212 2)\u03b3H\u03c4F + \u0393 2\u03b32 H + \u03b42(1\u2212 n2/N2). (5.3) For given n, one can then read off the value of \u03b3H at which the instability occurs. In general, different modes of n can become unstable; however, within the family of helices parametrized by \u03b3S, the mode n = 1 is always the first unstable mode as the control parameter is increased. It is this case that corresponds to our \u2018secondary\u2019 bifurcation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure19-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure19-1.png",
+ "caption": "Figure 19. Factors of the symmetric system of Example 3: (a) subspace V (1)\u2014factor ECC ; (b) subspaces V (2) and V (3)\u2014factors DCC and DDD ; (c) subspace V (4)\u2014factor EDD ; and (d) subspaces V (51) and V (52)\u2014factors DC and CD .",
+ "texts": [
+ "1002/cnm form II stiffness and mass matrices, the blocks of which are in symmetry form II in turn. K= \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a3 A1 B1 A2 B2 B1 A1 B2 A2 A2 B2 A1 B1 B2 A2 B1 A1 \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a6 8\u00d78 3 4 8 7 1 2 6 5 k1 k1 k1 k1k2 k2 k3 k3 k2 k2 k6 k6 A system with 16 DOFs is studied. Figure 18 shows this system and its graph model. In this model, we have m1 =m2 =m5 =m6 =m9 =m10 =m13 =m14 =m, m3 =m7 =m11 =m15 =m\u2032 and m4 =m8 =m12 =m14 =m\u2032\u2032 Symmetry operations of this graph comprise of the symmetry group C4v . The factors of this structure are shown in Figure 19. It can be observed that the factors resulted by both group-theoretical and algebraic method, are identical. Considering the factor of the subspace V (51) and its graph model, as shown in Figure 19(d), it can be seen that this factor has a vertical plan of symmetry, which suggests the point group C1v . In the other words, this factor is of canonical form III symmetry and can be further decomposed. The result of decomposition of this factor is shown in Figure 20. Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm As it is seen, factors DDC and DCD are exactly the same as factors DCC and DDD , shown in Figure 19(b), and do not have to be solved. Thus, instead of solving a problem with 16 DOFs only a number of small problems are being solved: a one-dimensional problem and three problems of dimension three. This can some how highlight the efficiency of the proposed method. The procedure introduced in this paper consists of forming the graph model of a mass\u2013spring system, recognizing the symmetry operators and symmetry group of the graph, selecting the positional functions of the nodes of the graph as the basis vectors of the vector space of the problem"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003438_j.talanta.2005.01.036-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003438_j.talanta.2005.01.036-Figure2-1.png",
+ "caption": "Fig. 2. Schematic representation of the thin-layer radial flow microsensor: glass-based screen-sputtered Au ring-disk electrode (left), plastic cover with micro-flow injection system and conventional electrodes (right).",
+ "texts": [
+ " PBS was used both as solvent for preparing lucose and H2O2 stock solutions and as background olution for electrochemical analytical measurement. The queous solutions of GOx, HRP and AOx in 2 units l\u22121 ere prepared using doubly distilled water. The aqueous olution of 2 mM K3Fe(CN)6 and 0.1 M KNO3 served or cyclic voltammetric investigation. Ruthenium complex u3( 3-O)(AcO)6(Py)3(ClO4) (Ru-Py) was used as received rom other research group. .2. Fabrication of microsensor A thin-layer radial flow ring-disk microsensor (Fig. 2), onsisting of the glass base and the plastic cover, was deigned for the conventional three-electrode electrochemcal analysis. A screen-printed Au ring-disk electrode disk \u03c6 = 3 mm, S= 7.06 mm2; ring inner \u03c6 = 4 mm, ring idth=1 mm, S= 15.7 mm2) was applied as base. The disk part was coated with ascorbate oxidase in order to pre-oxidize the ascorbic acid. The ring part was modified by GOx and the mediator as the working electrode. On the cover, there were the micro cell (about 10 l with the suitable diameter to the ring-disk electrode), a Ag/AgCl wire (0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002646_acc.1991.4791487-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002646_acc.1991.4791487-Figure2-1.png",
+ "caption": "Fig. 2. Advaned Technology Wing wind-usnl model.",
+ "texts": [
+ " Aerodynamic cotwl is provide by fourconrl surfces on ech Wing: leading edge outod (LO), ledig edge inbord (L), trailing edge outboard (TO), and tailing edg ibord T) surfaces. Loading on the Wing exists in re fm: tosion momnt, bending m t, d hinge moment in this paper we consider only control of the torsion m ts The n mo s are meaured by strin gauge at the wing midpan and root, which correspond to the ouboad torsion manent and the inboard torsion moment, respeively. A diagram of the ATW identifying the cotrl swfm and tors moment locations is shown in Figure 2. The task of the roll controller is to detamine the a iat control swrfc tions hat will ahieve a comanded rol rait as well as satfy pre bed torsion ent constaints. Aldtough te are eight control sfaces availk on te ATW, the contributio to the roll maneuver from the left and right laing edge ibxd surfacs is negligible. hIerefore, for our purpose they are excluded as usable actaos. In what follows, we will use t symbio to denote srface deflection and\u00b6 to&nc*e torsion mn e.. Subsc sland t denot leading and tiling edge; sipts i and o denote inboard and outboard; and subscripts r and I denote right and left"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000979_1.2802427-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000979_1.2802427-Figure7-1.png",
+ "caption": "Fig. 7 Mechanism for measuring inertia tensor of large mechanical systems",
+ "texts": [
+ " Journal of Dynamic Systems, Measurement, and Control MARCH 1999, Vol. 121 / 115 Downloaded From: http://dynamicsystems.asmedigitalcollection.asme.org/ on 05/17/2015 Terms of Use: http://asme.org/terms hence CTI and errors increased. As in the first test, the dimensions of the inertia ellipsoid were identified with good accuracy. Table 3 compares the accuracy of the proposed method with those of other methods (Conti and Bretl, 1989; Pandit and Hu, 1994) and shows lower errors for the proposed method. The second mechanism is shown in Fig. 7. It was developed with the aim of measuring the inertia tensor of large mechanical systems (mass range: 50-200 kg, maximum dimension about 2 m), like the equipment installed in satellites. The inertia tensors of several pieces of equipment were identi fied with good accuracy, because the ratio between residual root mean square a^ and the smaller principal moment of inertia was about 2.5 percent. 7 Conclusions The proposed method for identifying of the inertia tensor of rigid bodies is quite fast, because it requires only one accurate positioning of the specimen and allows the inertia tensor of large bodies to be determined"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002310_1.2831616-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002310_1.2831616-Figure4-1.png",
+ "caption": "Fig. 4 Procedure of experiment, (a) Free; (b) liquid bridge; (c) return to initial position by elastic stage 2; (d) the offset force, Foi (e) generation of lubrication film by sliding.",
+ "texts": [
+ " 3, but the output can be approximated by a straight line which passes through the origin of the coordinate axes. The change of load caused by the inclination during the sliding is less than 2 /uN. Journal of Tribology OCTOBER 1996, Vol. 1 1 8 / 8 3 3 Downloaded From: http://tribology.asmedigitalcollection.asme.org/ on 02/21/2018 Terms of Use: http://www.asme.org/about-asme/terms-of-use I / / It I Fo (a) Free (d) The Offset Force, Fo Next, the balance of forces is considered carefully. After ensuring parallelism, the two mica surfaces are separated by a small distance (Fig. 4(a)) and a small amount (0.1 ~0.2 cc) of OMCTS is carefully dropped between the mica surfaces by a syringe. The mica surfaces approach each other by an attractive meniscus force (Fig. 4(b)) . The mica surface supported by the double cantilever spring is moved to an initial position in order to remove the deflection of the double cantilever spring using the elastic stage 2 (Fig. 4(c) ) . Under this condition, two sur faces are attracted to each other by the meniscus force, F\u201e, and the van der Waals force, F\u0302 ^w and repulsed by the compressive Hertz pressure. Then a pulling force, Fo is applied by using the double cantilever spring (Fig. 4(d)) in order to cancel F\u201e be cause Fm is very large compared with F^^w Note that Fo must be smaller than F,\u201e in order to avoid the surface separation. When the surfaces are slid by the elastic stage 1, the two sur faces separate from each other with film thickness h because fluid force is generated between the surfaces (Fig. 4(e)) . The fluid force is generated by the wedge effect (Cameron, 1966) between mica surfaces and this force is the predominant one in a lubricating film where the lubricant film thickness is relatively large, e.g., larger than 10 nm. The counterbalance of forces is written as: F - F^ciw + Fm - (Fo - Fj) (1) where F is the fluid force and FQ \u2014 F, is pulling force applied by the double cantilever spring and F, = k^h, where h is the minimum film thickness. An example of film thickness measurement (output data from the displacement sensor during sliding) is shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002968_j.conengprac.2003.12.013-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002968_j.conengprac.2003.12.013-Figure2-1.png",
+ "caption": "Fig. 2. Simplified launcher representation.",
+ "texts": [
+ " * Control the destabilizing bending modes: the aim is to attenuate these modes under a gain limit (XdBo0) except for the first one which can be controlled in phase with a sufficient delay margin (at least one sample period Ts). * Time domain specifications: * Limit the angle of attack i in case of wind disturbance (a typical wind profile will be given in Fig. 12). * Limit the angle of deflection b and its velocity \u2019b: * The consumption C must be limited to Cmax where C \u00bc XTend k\u00bcTinit b\u00f0k \u00fe 1\u00de b\u00f0k\u00dej j: \u00f01\u00de * Robustness * All these objectives have to be robust against uncertainties (which affect rigid and bending modes). A simplified launcher scheme is given in Fig. 2 where the angle of attack between the launcher axis and the relative speed VR is noted i; the attitude c; the angle of deflection b (control input) and the wind velocity W (disturbance). The ARTICLE IN PRESS B. Clement et al. / Control Engineering Practice 13 (2005) 333\u2013347 335 sensors allow measuring the attitude and its velocity whereas the actuators allow controlling the angle of deflection for the thrusters. The challenge of such a control issue is to minimize the angle of attack i which in addition cannot be measured"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001047_iros.1994.407656-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001047_iros.1994.407656-Figure8-1.png",
+ "caption": "Figure 8. Orientation of Group Pattern",
+ "texts": [
+ " The limitation of this algorithm is that it cannot be used in cases when some requirement on the goal orientation has to be met. 3.3.2 Object's Orientation Changes as Specified In many object transportation tasks, not only the goal location is specified but also its orientation. We propose the following algorithm to coordinate the motion of the followers in order to meet this performance requirement. To describe the position and orientation of the group pattern, we assume that there is a local coordinate system attached to the group leader as shown in Figure 8. The orientation of the group pattern can then be described by %t) as shown in Figure 8. In Figure 8, we let the origin of the local coordinate system be at the center of the leader. Suppose that the sensory and communication devices on each follower allow the follower to determine the leader's location and its own location with respect to the world coordinate system. After the robots have formed a specified pattern, each robot computes its relative position with respect to the leader, which is equivalent to its location in the local coordinate system. Let (a(i),b(i)) represent the location of the i-th follower in the local coordinate system as shown in Figure 8, where i = 1, 2, ..., N. In order to maintain the group pattern, each follower should remain steady with respect to the local coordinate system as the group moves. 3.3.1 Object's Orientation Remains Unchanged Upon receiving (v(t)$(t)), which is the leader's speed This \"leader following\" strategy requires minimum computation to be conducted by each follower. In applying this method, the followers move at a same speed and direction with the leader at all the times. Upon receiving the leader's broadcast information (v(t)$(t)), each follower calculates its desirable position at t+At as: xi(t+At) = xi(t) + v(t) At cos@(t)) yi(t+At) = yi(t) + v(t) At sin(p(t)) and steering angle, each follower computes its desirable location at t+At with respect to the world coordinate system individually"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure9-1.png",
+ "caption": "Figure 9. A symmetric dynamic system with three DOFs and its graph model.",
+ "texts": [
+ " As it was observed, the decomposition is resulted only by the aid of symmetrical properties of the system. The symmetry of systems studied in the previous examples was almost simple, consisting of one symmetry operation only, however the power and efficiency of the group-theoretical method become more apparent when a system contains more symmetrical properties, establishing point groups of higher orders. Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm As a simple example, which possesses rather more complex symmetry, the system shown in Figure 9 is considered. Although this system does not seem symmetric, its symmetry operations become apparent when its graph model is studied. This system has three translational DOFs, which result in a 3\u00d7 3 stiffness matrix as follows: K= \u23a1 \u23a2\u23a3 k1 + 2k2 \u2212k2 \u2212k2 \u2212k2 k1 + 2k2 \u2212k2 \u2212k2 \u2212k2 k1 + 2k2 \u23a4 \u23a5\u23a6 Having a C3 as its principal axis and three vertical planes of symmetry, this system belongs to the symmetry group C3v , with set of operations as: {e,C3,C \u22121 3 , 1, 2, 3}. Referring to the character table of this group [15]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001500_978-1-4899-1465-1-Figure7.4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001500_978-1-4899-1465-1-Figure7.4-1.png",
+ "caption": "Figure 7.4. Equivalent circuit of de motor.",
+ "texts": [
+ " Process lines requiring that tension be maintained on material being processed can save energy by replacing mechanical brakes with regenerative, adjustable-speed drives. Because of the potentials for energy savings that exist with vari able speed, a discussion of several of the most common methods of achieving variable speed is presented in the following sections. 7.2. de Drives Direct current drives date back to the 1930s when the Ward Leonard system was patented by H. Ward-Leonard. They have un dergone many evolutionary changes over the years, but today the de drive remains one of the most versatile and widely used methods of speed control. Figure 7.4 shows the equivalent circuit of a dc motor. 122 Chapter 7 The flux is established by the field current If and the armature rotating through this flux generates a counter emf, Ec. The armature has some finite value of resistance shown as RA in the figure. The equations relating these quantities are (7.4) (7.5) where Kf = constant of proportionality between field current and flux, Ke = constant of proportionality between (speed X flux) and armature counter emf, and n = rotational speed of armature"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure4-1.png",
+ "caption": "Fig. 4. The deformation of an in\u00aenitesimal element whose undeformed and deformed con\u00aegurations are rectangular parallelepipeds.",
+ "texts": [
+ " Geometric interpretation of polar decomposition The above discussions reveal that the Jaumann strain measure is the most appropriate one for problems involving large rotations but small strains. Jaumann strains are de\u00aened by using the polar decomposition theory [2, 5], which decomposes the deformation gradient tensor [F] into a symmetric tensor [U] and an asymmetric tensor [R] as F R U 38 where [U] is the so-called right stretch tensor and [R] accounts for rigid-body rotations. The Jaumann strain tensor is de\u00aened as B U \u00ff I 39 where [I] is a 3 3 unit matrix. To understand Jaumann strains Bmn, we consider the deformation of an in\u00aenitesimal parallelepiped, as shown in Fig. 4. Here the frames x1x2x3 and x\u00cf1x\u00cf2x\u00cf3 are two inertial orthogonal frames and the frames x1x2x3 and x1 x2 x3 represent the rigidly translated and rotated con\u00aegurations of x1x2x3 and x\u00cf1x\u00cf2x\u00cf3, respectively. The movement of the in\u00aenitesimal parallelepiped consists of a rigid-body translation which moves the point A to the point a, a rigid-body rotation which rotates the frame x1x2x3 (x\u00cf1x\u00cf2x\u00cf3) to the frame x1x2x3 ( x1 x2 x3), and pure stretches along the axes x1, x2 and x3. The coordinate systems are related as fi123g T fj123g, 40a fi 1 2 3g C Tfi123g, 40b fj 1 2 3g C Tfj123g 40c where {j123}0{j1, j2, j3} T, {j1\u00cf 2\u00cf 3\u00cf }0{j1\u00cf , j2\u00cf , j3\u00cf } T, {i123}0{i1, i2, i3} T, {i1\u00cf 2\u00cf 3\u00cf }0{i1\u00cf , i2\u00cf , i3\u00cf } T, jk are base vectors of the system x1x2x3, jk\u00cf are base vectors of the system x\u00cf1x\u00cf2x\u00cf3, ik are base vectors of the system x1x2x3, and ik\u00cf are base vectors of the system x1 x2 x3",
+ " If g61$g62, the rotation of the frame x1x2 is not equal to the average of the rotations of the axes x\u03021 and x\u03022. This fact may not be important in geometrically nonlinear analysis but it is important in elastoplastic analysis because vg61\u00ffg62v can be large due to e1>>e2 or e1<?J&. 2) Compute the images of the vertices of S , under\n3 ) Form the convex hull of the image points obtained in\n4) Solve for the intersection of a vector in the direction of\n128.68\u201d, and 0 3 , = 25.66\u201d. These values are obtained from the relation 8 = O(q). After we obtain the analytic forms of J,(q) and J, (q) , we can plug the value of q into them to obtain ( JL>+ Je. (2) to obtain S , in I;.\na and the boundary of S,.\n- v 5 3 JL(? 3 \u2019 \u201d) 3 = [ ? 71 -9.4651 1 0 -8.465 18.93 It can be seen that all the above steps involve only analytic\ncomputations. Therefore, the procedure proposed here to J& - , - = 0 1 -7.100 14.20 6 100 \u2019 solve the dynamic workspace analysis problem for multiple (3 \u20193\u201d) [ cooperating robot arms is computationally rather simple. We ignore the gravity terms and assume that the robot\nThe joint-driving torques that produce the maximum chain is at a steady state. Then we have force/torque F can be easily computed by plugging the value of F into (2). Pseudo inverse of JA is then necessary in the S , = { T I - 1 0 N . M . S T ~ , T ~ , T ~ , , T ~ , I l O N . M . ,\nv\ncomputations. Consideration can be made in choosing this -5 N.M. I T-,, C: 5 N.M.} pseudoinverse to accommodate constraints such as different robot arms\u2019 capabilities.\nIn some applications, it is necessary to find the maximum magnitude of the force that m robot arms can jointly apply while keeping magnitude of the torque applied at a predetermined value. Solution of this problem can be achieved based on the solution of the dynamic workspace analysis problem. Given the directions of the force and torque vectors to be applied, a force/torque vector F can be found that has the maximum magnitude for both the force and the torque subvectors. The force/torque vector F\u2019 that contains a force subvector of maximum magnitude and a torque subvector of given magnitude can be obtained by simply scaling down the magnitude of the torque subvector in F to the specified value. This is possible since the maximum F requires full potential of the arms, whereas scaling down the torque subvector only reduces the utilization of the arms\u2019 capabilities. Therefore, we have, if F = (fxfyfit,tytz)\u2019, then F = ( fxfyfzct ,c t ,c tz)\u2019 can be found such that c . 1 ( t x t y f z ) \u2019 1 equals the specified value. The corresponding joint driving torques to produce F can again be easily found by plugging F\u2018 into (2).\nWe conclude this section by an example that illustrates the application of the above method to a simple two-arm closed chain.\nExample 1: We consider a two-arm closed chain consisting of a two-link planar arm and a three-link planar arm rigidly connected together at the end point of their last links, as shown in Fig. l(a). The parameters of the two robots are given as - 10 N.M. I r 1 I 10 N.M., - 10 N.M. I T, I 10 N.M., and 1, = I, = l m for the first arm and - 10 N.M. i\nr 3 , I 5 N.M. and I,. = 12, = l m , 13, = 0.5m for the second arm. The distance between the center points of the bases of the two arms is d = 2m. We present here only numeric results because of space limits. We choose generalized variables q to be q = (q,q2)\u2019 = (O,O,)\u2019. That is, they are the joint variables of the two-link arm. The origin of the compliance frame C is assumed to be at the connection point of the two arms, and its axes are chosen to be parallel to those of the world frame. Based on these choices and the given data, we have, at q = ((7r/3),(57r/3))\u2019, O , , = 25.66\u201d, 0 2 , =\nT ~ , I10 N.M, -10 N.M. IT^, I 1 0 N.M., -5 N.M. I\nwhich is a five-dimensional rectangular parallelpiped. The image S , of S , under JL(( K /3), (57r /3))- J&(( ?r / 3 ) , (5n/3)) is a convex decagon. The graphs of S , and S, are shown in Fig. l(b) and l(c). The mapping between S , and S , is such that point ( A L ) is mapped to P,, (BL) to P 2 , ( B I ) to P3, ( B J ) to P4, ( B F ) to Ps, (CF) to P6, ( D F ) to P,, ( D G ) to P,, ( D H ) to P9, and ( D L ) to Plo . Given a direction in the compliance frame C in which we wish to apply a force as large as possible, we can immediately find an F vector in this direction on the boundary of S,. For example, the maximum load this robot chain can lift is the maximum force it can apply along the fy axis. This is given by the vector F, in Fig. l(c), which has a length of 170.83 N.\nThe solution procedure presented here for Problem 1 is modified in the next section to apply to the dynamic workspace analysis of multiple cooperating robot arms with internal force/torque constraints.\nIV. DYNAMIC WORKSPACE ANALYSIS OF MULTIPLE COOPERATING ROBOT ARMS WITH INTERNAL\nFORCE/TORQUE CONSTRAINT When the internal force/torque constraint is present, the optimization problem associated with the dynamic workspace analysis problem for multiple cooperating robot arms is the same as Problem 1 except for the additional constraint given by (5) and (6). We restate the problem here as follows:\nMaximize I F 1 with respect to Fnet, Subject to\nF = l F l a m\n1 Fi=O, i = I\nI Fil I F,,, J;lF = Jljrnet, i = l ; . . , m\n, n, , where Fi, i = 1; * . , m, are as defined in Section II-B.\ni = l ; . . , m j = 1,. -\nBecause of the presence of the additional constraint, solu-\nT T -,- -\nscription prices!",
+ "594 IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 7, NO. 5, OCTOBER 1991\ntion of the above problem is not as straightforward as for Problem 1. We define the following notations in our discus-\n1 r j r n,}, i = I ; . . , m\nsion of maximizing F while limiting the magnitude of internal force/torque. s;= { P = (~~)(~~)~rLet l rLet\u20acS~}, i = l ; . - , m .\nDefining CE,Sb = { C L I F ' I F i e $ , i = l; . . , m}, it is easy to see that S, = Xy!,lSk. That is, the polygon S, can be found by obtaining Sh's first and then adding them together.\nThus the optimization problem associated with the dynamic workspace analysis of multiple cooperating robot arms with internal force constraints can be written as",
+ "LI et al.: DYNAMIC WORKSPACE ANALYSIS OF ROBOT ARMS\nt 'y\n595\n-40 k\nObviously, the above procedure provides only a guideline to find the maximum force/torque that m cooperating robot arms can apply to the environment in a given direction without violating the internal force/torque constraints. Efficient computation algorithms are to be developed to speed up the computation. The following simple example illustrates the above approach.\nExample 2: We consider a two-arm closed chain consisting of two identical two-link robot arms configured as in Fig. 2(a). We find the maximum weight this two-arm chain can lift (maximum force applied in the fy direction) under the internal force constraint 1 Fi I I Fcm, where the internal force direction is given as parallel to the f, direction. The\n(b) I arms. (b) Maximum force parallelograms for the two-link planar arms.\nparameters of the two-arm chain are as follows: I, = I, = 11, = 12, = 1 m, 17; 1 5 10 N * M., i = 1,2, l', 2'. The configuration of the two arms are given as 8 = (a /2), 8, = - (a /6), 8 = (a /2), 0 2 , = (n /6). Given these parameters and the configuration of the two-arm chain we obtain the maximum force parallelegrams Sb and S i as shown in Fig. 2@).\nThe maximum weight that this two-arm chain can lift is obtained by adding up the components of F 1 in S i and F2 in Sg in the direction of f,, while maintaining the components of F' and F2 in the f, direction to be of the same magnitude but with opposite direction. It can be seen that, under these requirements, the maximum weight this two-arm chain can lift remains at 20 N as long as 1 0 6 N CC F,, 5 40 + 1 0 6 N. The maximum weight it can lift becomes smaller if Fcm < 1 0 6 N.\nV. CONCLUSIONS\nThe problem of finding the maximum force/torque in a compliance frame that multiple cooperating robot arms can apply is discussed in this paper. The solutions of these problems provide basis for the task planning for force control of multiple cooperating robot arms. We formulated these problems as optimization problems under the constraints of the dynamic equation of the robots and their joint-driving torque limits. We also took into consideration the constraints on the maximum internal force/torque that the object the robot arms are in contact with can withstand, whereas the cooperating robots are modeled by a closed mechanical chain. Conceptually simple procedures are developed to solve these optimization problems. These procedures also provide deep\nT -,- - scription prices!"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003364_0020-7403(88)90076-8-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003364_0020-7403(88)90076-8-Figure5-1.png",
+ "caption": "FIG. 5. Sl id ing con tac t , # = 1.0. (a) v = 0.3; (b) v = 0.5.",
+ "texts": [
+ " This is in contrast with some earlier solutions in which an approximate integral equation formulation approach was adopted, but where the kernel was itself expressed as an integral; these solutions demand a separate treatment if the material is incompressible [10, 11-]. Full slip The treatment above can be extended to cover the case where full slip takes place, i.e. where one roller is sliding with respect to the other. In this case the shear traction is simply proportional to the normal pressure, so that equation (13) becomes: 4(1 - - v 2 ) 2B s - 1 2 D R A 2 2meA 2 m 2 A 2 P , E I A ( n - - m ) + b t l a ( n - - m ) ] -- _ _ + - - $2 rrE Z n = - ( S - 1 ) a aS m = - S . . . . . S. (15) The equations are then solved as before. Sample results are shown in Fig. 5 obtained with S = 10. Once again the appropriate halfplane solutions are recovered for large tyre thicknesses. For v ~ 0.5 the appropriate solution is that for the sliding of dissimilar elastic half-planes, since the thick tyre approximates an elastic half-plane in contact with a rigid cylinder. Solutions are given by Buffer [12] and Hills and Sackfield [13]; they agree well with the numerical results obtained here for large tyre thicknesses. Figure 5(a) demonstrates the coupling present between shear and normal tractions which leads to the asymmetric distribution, together with a non-zero value for e. This effect is largest for thick tyres and diminishes as the thickness is decreased and the layer becomes less compliant. The case of an incompressible tyre (v = 0.5) leads to different results, as illustrated in Fig. 5(b). This value of v eliminates the coupling present in the half-plane solution so that a Hertzian distribution of pressure is appropriate. Coupling is now introduced as the tyre thickness is reduced, and it should be noted that this is opposite in sign to that caused by the elastic mismatch for v = 0.3 (i.e. the peak pressure occurs on the entry side of the contact for v = 0.3 and on the exit side for v = 0.5). Full adhesion The next case to be considered is that of adhesive rolling, where the two rollers are adhered over the entire contact patch"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure20-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure20-1.png",
+ "caption": "Fig. 20 Schematization of the wheel and subdivision in \u00aeve truncated-cone zones for the analytical calculation with the simpli\u00aeed model",
+ "texts": [
+ " The height of each rectangle in the \u00aegure represents the load range corresponding to the design interference range. The simpli\u00aeed model is based on the following hypotheses: 1. The material behaviour was considered to be linear elastic. 2. The wheel and the axle were considered to be axisymmetric bodies. This means that the in\u00afuence of the tangential actions due to friction on the stress and strain state of these components has been neglected. 3. The wheel was schematized in \u00aeve truncated-cone zones, as shown in Fig. 20, whose dimensions depend on the actual wheelset geometry. This equivalent wheel geometry has been de\u00aened on the basis of the previously described FEM analyses. For the wheelsets analysed it was proved to give results very similar to those obtained by the FEM, with errors less than 2 per cent on the maximum press-\u00aet load. 4. The contact pressure distribution in each of the \u00aeve zones is obtained from Lame\u00c1 formulae, considering the zone to be composed of several in\u00aenitesimal cylindrical layers with an external radius r\u2026z\u2020, as Proc"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.13-1.png",
+ "caption": "Figure 1.13. Description of the intrinsic reference frame and the intrinsic velocity and acceleration vectors in the osculating plane.",
+ "texts": [
+ "71) wherein s = ds/dt is called the tangential acceleration component and 1d2 is named the normal acceleration component. Since the normal component is directed toward the center of curvature, it also is known as the centripetal acceleration component. The result ( 1. 71) shows that the acceleration vector of P lies always in the osculating plane tangent to its path and containing the cen ter of curvature. The foregoing description of the intrinsic frame t/1 = { P; tk} and the intrinsic velocity and acceleration vectors in the osculating plane at P are illustrated in Fig. 1.13. 32 Chapter 1 The curvature K, or the radius of curvature R, is given by K=~= 1:1 =~~~I\u00b7 (1.72) in which (} is the angle between the tangent vector t and an arbitrary fixed line in the osculating plane. Two easyapplications of (1.72) deserve special men tion. (i) Rectilinear Motion. A motion on a straight path is known as a rec tilinear motion. The tangent vector on a straight path obviously is a constant vector; hence, by ( 1. 72 ), we have K = 1/ R = 0. That is, a straight line path has zero curvature, hence an infinite radius of curvature",
+ "74) Finally, it is easy to verify that the tangential and normal components of the intrinsic acceleration of a particle and the curvature of the path can be computed from the relations a\u00b7v a,=s=-, v \u00b72 Ia xvl an::Ks =--, v (1.75a) (1.75b) (1.75c) Kinematics of a Particle 33 in which v = s i= 0. The construction of these results is left as an exercise for the student. It should be observed that whereas s= lvl, in general si= lal. Rather, by (1.71) (1.76) We have learned that equations (1.70) and (1.71) are the representations of the velocity and acceleration expressed in terms of a basis that is moving relative to an assigned Cartesian frame l/J = { 0; ik }, as shown in Fig. 1.13. They must not be confused as the velocity and acceleration relative to the intrinsic frame, for it is clear that the particle has no motion relative to an observer situated at the origin of that frame. Rather, the relations (1.70) and ( 1. 71) are representations of the velocity and acceleration of a particle relative to the assigned rectangular Cartesian frame l/J but referred to the moving, intrinsic frame 1/J. Said differently, the intrinsic velocity and acceleration com ponents are the instantaneous projections upon the moving, intrinsic frame 1/J of the velocity and acceleration as seen by an observer stationed at 0 in frame l/J",
+ " Kinematics of a Particle 41 The speed of the particle is the time rate of change of the distance s(t) traveled along its path: [ cf. ( 1.13 )]. The velocity and acceleration relative to cp have an especially simple and useful representation when referred to the intrinsic reference frame I{!= { P; tk} that follows the particle: v = st, [ cf. ( 1. 70 )-( 1.71 )]. The velocity vector is in the direction t tangent to the path. The acceleration, if it is not zero, is in the osculating plane and directed toward the concave side of the path, as shown in Fig. 1.13. Among all planes at the point P on the path, the osculating plane lies nearest to the curve at P; it is determined by t and the principal normal vector n directed from P toward the center of cur vature. The curvature K, or its reciprocal, the radius of curvature R, is a measure of the rate of turning of the tangent line along the path: K=~= ~~;~ = ~~~~ [cf. (1.72)], wherein e is the angle that the tangent vector makes with a fixed line in the osculating plane. All of these properties are independent of the coordinate system used in the spatial frame"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002883_robot.2004.1302491-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002883_robot.2004.1302491-Figure1-1.png",
+ "caption": "Fig. 1 Structure of the Microrobot",
+ "texts": [
+ " This paper describes the new structure and motion mechanism of an underwater microrobot using ICPF actuator, and discusses the swimming possibility of the microrobot in water. Characteristic of the underwater microrobot is measured by changing the frequency (from 0.1Hz to 5Hz) and the amplitude (from 0.5V to 1OV) of input voltage. The experimental results indicate that the swimming speed and the buoyancy of the underwater microrobot can be controlled by changing the frequency and the amplitude of voltage. II. STRUCTURE OF THE MICROROBOT A. Total Structure of the Microrobot Fig.1 shows the basic structure of the developed underwater microrobot using ICPF actuator. This microrobot consists of the body made of wood material shaped as a fish (A), a pair of tail with a fin driven by ICPF actuator respectively (B), the lead wires for supplying electric energy to ICPF actuators (C) and a pair of fins are installed in parallel structure for generating a large propulsive force. The fins are driven independently. The buoyancy adjuster under of the microrobot body is also driven by the same ICPF actuator",
+ " Displacement of the ICPF is proportional to the electrical voltage in put on its surface as the swelling of polymer gels. The other characteristic of the ICPF actuator is that when the frequency of the applied voltage is low less than 0.3Hz, water around the ICPF surface is electrolysed, so water bleb on both side of the ICPF surface is generated. In result of the change of body volume, and buoyancy of the microrobot can be controlled. ICPF actuator (0 .2~3~15mm) is cut in a strip to drive a fin for propulsion, and ICPF actuator (0.2~4~6mm) is used for buoyancy adjuster as shown in Fig.1. 0-7803-8232-3/04/$17.00 02004 IEEE 4881 Body Solenoid Pennanmt magnet Fig2 sture (b) DOF (c) Underwater Micro Biped Robot with 1 DOF Fig.3 View of the Developed Microrobot III. MOTION MECHANISM OF MICROROBOT The developed microrobot has two tails with a fin driven by the ICPF actuator respectively as shown in Fig.1. A pair of fins is offset in the distance d, and driven by electric voltage of fl and f2 frequency independently as shown in Fig.4. A motion of a fin is described by combination of two kinds of motion, feathering and heaving . When proper phase difference appears between heaving and feathering, the fin generates an effective force as shown in Fig.5. The propulsive force is the sum of drag force vectors to the moving direction in equation (1). It can be realized by changing frequency fl, E2 of the electric voltage applied on the ICPF actuators that the moving motion in the directions (forward, right turn and left turn) as shown in Table"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000704_a:1008228120608-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000704_a:1008228120608-Figure9-1.png",
+ "caption": "Figure 9. (a) Permanent event map generated with Vdr = 0:082377. There is no fixed point, the interval \u2018a\u2019 is mapped into \u2018b\u2019 and vice versa; (b) the f 2 map shows the existence of a homoclinic orbit.",
+ "texts": [
+ " Figure 7 shows the bifurcation diagram of the attractor \u20182\u2019 in a portion of the range of small driving velocities; starting from Vdr = 0:0846 the attractor undergoes a period-doubling cascade giving birth to an apparently chaotic attractor which suddenly disappears for Vdr 0:08058. A sequence of one-dimensional maps in the non-periodic region can be seen in Figure 8; the shape of those maps constitutes evidence of the chaotic nature of the system. For values of the driving velocity close to Vdr = 0:082377 (see bottom right of Figure 8) and above, the steady state part of the one-dimensional iterated mapping is composed of two (or more) separated branches; see also Figure 9a. This separation into two branches clearly rules out the existence of odd periodic orbits since f(a) :! b, f(b) :! a, and a \\ b = ;, where a and b are the two intervals where the permanent portion of the map is defined. The only exception is a fixed point in between the two branches (not shown). The map is, however, still continuous as the transient part of the map shows (not shown on Figures 8 and 9). Considering Figure 9b and the illustrative trajectories shown, it is evident that the map possesses a so-called snap-back repeller, or in more traditional terms a homoclinic orbit to the unstable fixed point; the fixed point is, of course, a fixed point for the second iterate of f , and in reality is a prime period-2 orbit. The fixed point for the second iterate is located at approximately d = 0:1624. The snap-back repeller is sufficient for the existence of chaos [11, 18]. That is, there exist periodic points of any prime period (for the second iterate), and uncountably many orbits that are not even asymptotically periodic"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003395_bf01022266-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003395_bf01022266-Figure7-1.png",
+ "caption": "Fig. 7. Double channel electrode cell.",
+ "texts": [
+ "7cm, Vr = 10 -3, 10 2, 10-t and 1 c m 3 s - I , D = 10 -5 cm 2 s -~, d = 0.6 cm and b -= 0. t cm), heterogeneous rate constants in the range 10-1 _ 10- 5 cm s - ~ may be measured. The general observat ion to be made is that slower flow rates favour the measuremen t of slow rate constants. 3. Experimental details 3.1. The flow cell and flow system The flow cell and flow system have previously been described [13, 15], and so only a br ief description will be given here. Exper iments were carried out using the cell shown in Fig. 7, which was fabr icated in Perspex. The channel is 40 m m long, 6 m m wide and approx imate ly 1 m m deep. A precise value for the latter pa rame te r was found f rom the slope of a Levich plot ( t ransport - l imited current vs (flow rate ~/3) [20], obta ined f rom an electroactive species o f known diffusion coefficient. A cover plate bore the substrate - in this case a piece of cot ton cloth - onto which were cemented to the electrodes. The electrodes consisted of strips cut f rom pla t inum foil, 0 . 0 2 5 m m thick (99.95%, Goodfet lows, Cambr idge , U K ) . The upstream electrode was located 3-4 mm downstream of the upstream edge of the cloth, and the upstream region of the substrate was masked from the solution with thin PTFE tape, as shown in Fig. 7. The edges of the substrate and electrodes were treated in the same manner, as illustrated, so that the width of the exposed substrate and electrodes was approximately 4mm. This arrangement ensured that flow over the reactive interface was of a plug nature with respect to the z direction; edge effects (in which v x deviates from the expression given in Equation 3), occur over distance ~ b/2 [15]. In general, the lengths of the upstream and downstream electrodes were of the order of 2 and 4 ram, respectively, with a gap of l m m ",
+ " Connections between the PTFE tubing, the cell and the counter electrode were formed with silicone rubber tubing. Deoxygenated electrolyte was gravity fed from the reservoir via one of several calibrated glass capillaries, which gave a total flow rate range of 10-4-3 \u2022 10-~ cm 3 s-~. Adjustment of the rate of flow with each capillary was achieved by varying the height between the reservoir and the tip of the capillary, where the electrolyte ran to waste. Electrical contact to the two working electrodes was facilitated by extending the foils beyond the edge of the coverplate as illustrated in Fig. 7. Locating the cell and about 1 m of the preceeding tubing within an air thermostat allowed temperature control to 25 _+ 0.1~ 3.2. Materials Solution were made up using triply distilled deionized water (resistivity > 107 s cm). Ferricyanide solutions constituted approximately 5 x 10 .3 M potassium ferricyanide in 0.1 M sodium hydroxide and 1 M potassium chloride to serve as background electrolyte. Bromide solutions were approximately 10 -3 M in sodium bromide, 0.5 M sulphuric acid acting as background electrolyte"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000813_bf01209025-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000813_bf01209025-Figure1-1.png",
+ "caption": "Fig. 1. Kinematic variables and axes.",
+ "texts": [
+ " We are going to explore the case when the ball and the surface 50 have only one point in common during all motion, so the curvature of the meridian of 50 (i.e., an intersection of 5 ~ and a vertical plane containing the line Z) is smaller than 1/a. In that case, the set S of all possible positions of the center of the ball is also a smooth surface of revolution with the same axis Z [4]. The position of the ball's center O can be described by geographical coordinates 0 and 9. The latitude O is an angle between the inner normal vector to S and the plane orthogonal to the line Z (see Fig. 1). The longitude 9 is the angle between the fixed plane containing the line Z and the mobile plane that goes through the line Z and the point O. Introduce a moving orthogonal basis eleze3. The vector el is a tangent vector to a meridian of S at O (i.e., an intersection of S and a vertical plane containing the line Z and the point O), e3 is the inner normal vector to S at O, and e2 is equal to e3 \u2022 e l . Let us denote the velocity of the ball's center by v and the angular velocities of the ball and the basis ele2e3 by co and ~ respectively"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001045_a:1019555013391-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001045_a:1019555013391-Figure1-1.png",
+ "caption": "Figure 1. Definition of the MBS structure.",
+ "texts": [
+ " We assume here that the structure is a topological tree, excluding the presence of any closed loops in the system. The dynamical model of the MBS is characterized by a set of inertial parameters describing the mass distribution of the bodies. These parameters could be considered individually for each body, but it is well-known that some of them combine together [3] to form the so-called barycentric parameters. These combinations can be performed a priori from the description of the topological structure (Figure 1): m\u0304i = \u2211 j :i\u2264j mj , (1) bi = \u2211 j :i\u2264j mj dij = [X\u0302i]t bi1 bi2 bi3 , (2) Ki = Ii \u2212 \u2211 j :i\u2264j mj d\u0303ij d\u0303ij = [X\u0302i]t Ki 11 Ki 12 Ki 13 Ki 12 Ki 22 Ki 23 Ki 13 Ki 23 Ki 33 [X\u0302i]. (3) where \u2022 i \u2264 j means that body i is an ancestor of body j in the tree structure; \u2022 dij (i \u2264 j) is the vector contribution of body i to the absolute position vector of joint j . We also define dij z as dij + zi; \u2022 x\u0303 stands for the skew-symmetric tensor associated with the cross-product by a vector x; \u2022 mj , djj and Ij are the mass, position vector of the center of mass and inertia tensor of body j ",
+ " The vector bi is the moment vector locating the mass centre of this augmented body and the tensor Ki is its inertia tensor with respect to its attachment point O \u2032i . In our formalism, the reference point for computing the resultant joint force Fi and pure torque Li (for joint i) being chosen as the point Oi (located on the parent body h), the following augmented parameters are also introduced: bi z = m\u0304izi + bi = \u2211 j :i\u2264j mj dij z ; Ki z = Ii \u2212 \u2211 j :i\u2264j mj d\u0303ij z d\u0303ij z (4) defined with respect to point Oi (Figure 1). The kinematic formulation is of course similar to the one used for the classical recursive Newton\u2013Euler scheme. We shall briefly recall these equations for our case. In Figure 2, the various kinematical elements are represented and in the following equations, \u03d5i and \u03c8 i represent unit vectors aligned with joint i axis, respectively for a revolute and a prismatic joint. For body i, one can write: \u2022 Absolute position vector: pi = ph + dhi z , for the attachment point Oi on body h. (5) \u2022 Absolute velocities: \u2013 angular: \u03c9i = \u03c9h + \u03d5i q\u0307i; (6) \u2013 linear: p\u0307i = p\u0307h + \u03c9\u0303h "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002725_zamm.19910710718-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002725_zamm.19910710718-Figure1-1.png",
+ "caption": "Fig. 1. a) Rigid object in an elastic frictional multifingered gripper. b) Hard finger-contact. c) Soft finger-contact",
+ "texts": [
+ " The numerical treatment of the resulting LCP by an appropriate algorithm gives normal reaction, tangential forces (friction forces), the slipping when it occurs and the corresponding rigid body displacement. In this paper a variant of LEMKE\u2019S algorithm (c.f. [14], 1151) is used to solve the problem. Numerical examples illustrate the theory. It is also shown by means of a numerical example that an object which is grasped with soft-fingers cannot be grasped with hard-fingers for the same external forces. 2. Problem formulation Let us consider in the orthogonal Cartesian coordinate system a rigid object which is grasped by a multifingered gripper with n frictional elastic fingers (Fig. 1 a). The contact between the object and the fingertips is modeled either as a hard-finger contact (Fig. 1 b) or as a soft-finger contact (Fig. 1c). The hard-finger contact can prevent displacements of the object in the normal and the tangential directions with respect to the object boundary, whereas the soft-finger contact can prevent in addition rotations of the object about the normal to the boundary axis passing through the contact point, up to a certain value of torque which depends on the normal contact force through Coulomb-type static friction. Under the above assumptions the relations which govern the frictional contact problem are the following: i) The g loba l equi l ibr ium equat ions where GN is the m x n equilibrium matrix corresponding to the normal contact reactions, C T is the m x 2n (m x 3n for the soft-finger case) equilibrium matrix corresponding to the friction forces (plus the frictional torques in the soft-finger case), rN = {r,,, rN2, "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003646_robot.2006.1642337-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003646_robot.2006.1642337-Figure1-1.png",
+ "caption": "Fig. 1. Stereographic projection for 1-D.",
+ "texts": [
+ " To make a projection, a line is drawn from the north pole to each point on the sphere and the intersection of this line with the projection plane constitutes the stereographic projection. For simplicity, we will illustrate the equivalence between stereographic projections and conformal geometric algebra in R 1. We will be working in R 2,1 with the basis vectors {e1, e4, e5} having the usual properties. The projection plane will be the x-axis and the sphere will be a circle centered at the origin with unitary radius. Given a scalar xe representing a point on the x-axis, we wish to find the point xc lying on the circle that projects to it (see Figure 1). The equation of the line passing through the north pole and xe is given by f(x) = \u2212 1 xe x + 1 and the equation of the circle x2 +f(x)2 = 1 . Substituting the equation of the line on the circle, we get the point of intersection xc xc = ( 2 xe x2 e + 1 , x2 e \u2212 1 x2 e + 1 ) , (5) which can be represented in homogeneous coordinates as the vector xc = 2 xe x2 e + 1 e1 + x2 e \u2212 1 x2 e + 1 e4 + e5. (6) From (6) we can infer the coordinates on the circle for the point at infinity as e\u221e = lim xe\u2192\u221e {xc} = e4 + e5, (7) eo = 1 2 lim xe\u21920 {xc} = 1 2 (\u2212e4 + e5), (8) Note that (6) can be rewritten to xc = xe + 1 2 x2 ee\u221e + eo, (9) B"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002495_12.497801-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002495_12.497801-Figure10-1.png",
+ "caption": "Fig. 10 Comparison ofgas pressure distribution on specimen surface in Ar and He gas.",
+ "texts": [
+ " Cross sections, X-ray inspection results and X-ray transmission observation results are summarized in Fig. 9. The penetration depth increases with a decrease in the pressure both in CO2 and YAG laser welding. Also, bubble and porosity formation was suppressed, and no porosity was formed under high vacuum although the bottom part of a keyhole was swollen. It was moreover revealed that the thin vapor plume upwards was induced, and the melt flow in vacuum was opposite to that in coaxial shielding gas. Fig. 10. The negative pressure was produced. Moreover, the negative pressure was more noticeable in Ar than in He because ofhigher gas density. The nozzle was first used in CO2 laser welding. The results are shown in Fig. 11. As the negative pressure increases, porosity is smaller and the number is reduced. The action of Ar is higher. Porosity is reduced remarkably at a low speed. It was confirmed that this nozzle was effective to the reduction in porosity at low speeds in both CO2 and YAG laser welding ofan aluminum alloy A5083"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002469_1.1468870-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002469_1.1468870-Figure1-1.png",
+ "caption": "Fig. 1 The different shapes of helical springs \u201ea\u2026 cylindrical \u201eb\u2026 barrel \u201ec\u2026 conical \u201ed\u2026 hyperboloidal",
+ "texts": [
+ " The results are given with six digits in order to enable comparison by other methods. As shown in Figs. 3 and 4, the mode shapes are presented in the global and the local coordinate systems as can be seen. All the mode shapes are coupled. In addition, the symmetrical and asymmetrical modes can be identified from the plots. Example 2: Noncylindrical \u201eHyperboloidal\u2026 Helical Spring In order to show the excellent performance of the dynamic stiffness analysis, the results are compared to finite element analysis results for a hyperboloidal type spring ~Fig. 1! fixed at both ends. It is clearly seen from Table 2 that the results obtained by the suggested method are the converged results of the finite element analysis. In Figs. 5 and 6, the first six mode shapes are presented. JULY 2002, Vol. 124 \u00d5 405 016 Terms of Use: http://www.asme.org/about-asme/terms-of-use 4 Downloaded Fr Here too the symmetrical and asymmetrical mode shapes are obvious in the mode shapes. Example 3: Noncylindrical \u201eBarrel\u2026 Helical Spring. For the second noncylindrical example, a barrel type spring ~Fig. 1! is considered. This problem has been studied by Nagaya et al. @8# using the Myklestad method. They have taken into account only the axial deformation, and neglected the rotary inertia. They have solved this problem by dividing every coil into 12 segments. Their results were obtained theoretically and experimentally. A close agreement between the results computed in the present study which are given in Table 3 and some of their results is demonstrated. It is also observed that the results of the present study are very close to those of Yildirim @9#"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003692_icmlc.2005.1527053-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003692_icmlc.2005.1527053-Figure2-1.png",
+ "caption": "Figure 2. Space voltage vector and stator flux vector in stationary reference frame",
+ "texts": [],
+ "surrounding_texts": [
+ "For three phase voltage source inverter, there are six non-zero active voltage switching space vectors (V 621, VV ) and two zero space vectors (V 70 ,V ). Six non-zero switching space vectors of three phase inverter are evenly distributed at 60\u00b0intervals with the length of 2Vdc/3 and form a hexagon (two zero space vectors are located at the center of the hexagon in the complex plane) as shown in Figure 1. Generally, in direct torque control of induction machine drives, there are ripples of torque and flux since none of the eight vector is able to generate the exact stator voltage required to produce the desired changes in torque and flux in the most of the sampling period. So, SVM is introduced in DTC for IM to reduce the torque and flux ripples. The voltage reference vector can be synthesized by two adjacent effective vectors (V andV *V i 1+i ) and two zero vectors on the basis of volt-second balance as in Figure 1, that is dtVdtVdtVdtV ss T TT TT T i T i T \u222b\u222b\u222b\u222b + + + ++= 21 21 1 1 0100 * (5) If *V is dynamically obtained on the control of IM, that is its amplitude and space position are adjustable, the ripples of torque and flux are expected to be decreased. As shown in Figure (2), in stationary reference frame, the stator flux variation can be resolved in two perpendicular components sf\u03c8\u2206 and st\u03c8\u2206 , where sf\u03c8\u2206 affects the stator flux magnitude, and st\u03c8\u2206 influences on torque magnitude. Synthesized space voltage vector *V is in the direction of s\u03c8\u2206 , and affects on both sf\u03c8\u2206 and st\u03c8\u2206 . In this paper, the magnitude of required voltage space vector is simplified as a constant, angle of *\u03b8 *V is the controlled variable. Since space position of stator flux can be calculated, the space angle of is able to be determined by predicting the angle of and stator flux, i.e. *V *V \u03b7\u03b8\u03b8 += s * (6) In formula (6), s\u03b8 is the angle between stator flux vector and d axis, which stand for actual position of stator flux. \u03b7 is called deflection angle, and obtained by torque error and stator flux error using fuzzy inference method in the paper. As described previously, DTC is direct control of flux and torque within the limits of flux and torque hysteresis bands by selection of optimum inverter switching vectors. predictive control method in DTC presented in this paper means the deflection angle of required voltage vectors is dynamically regulated, so that, more precise voltage vectors can be applied to the machine to reduce the ripples of torque and flux. Since the angle \u03b7 is function of torque error and flux error, a novel fuzzy logic DTC using SVM of IM is presented and shown in Figure 3. According to fuzzy logic technique, when angle \u03b7 is estimated, required voltage space vector is obtained, and SVM is able to adapt to control the machine, instead of using hysteresis comparators and optimum voltage switching vector lookup table as in conventional DTC. In the fuzzy logic estimator, there are two input variables, which are absolute torque error|ET|, stator flux error |E\u03a8|, one output variable is the deflection angle \u03b7 of synthesized voltage vector. Each universe of discourse of the torque error, flux error, and deflection angle is divided into four fuzzy sets. Triangle membership functions have been used. All the membership functions (MF) are shown in Figure 4 respectively. There are total of 16 rules as listed in table 1. Each control rule can be described using the input variables |ET|,|E\u03a8| and control variable \u03b7 . The th rule i iR can be expressed as : Z P S P M || \u03a8E P B || E T \u03b7 Z P S P M P B P S P M P B P B Z P S P M P B Z Z P S P M Z Z Z Z The inference method used in this paper is Mamdani\u2019s procedure (inference) based on min-max decision. The firing strength (applied fuzzy operators) ,for ith rules is given by i\u03b1 min( (| |), (| |))i A T Bii E E\u03c8\u03b1 \u00b5 \u00b5= By fuzzy reasoning, Mamdani\u2019s mininum procedure (fuzzy inference) gives ' ( ) min( , ( ))V i Vi i \u00b5 \u03b7 \u03b1 \u00b5 \u03b7= Where A\u00b5 , B\u00b5 and V\u00b5 are membership functions of sets A, Band V of the variables |ET|, |E\u03a8| and \u03b7 , respectively. Thus, the membership function V\u00b5 of the output \u03b7 is given by 16 ' 1 ( ) max( ( ))V Vii \u00b5 \u03b7 \u00b5 \u03b7 = = The Maximum criterion method is used for defuzzification, and the final single-valued output is obtained by this method. As stated above, in the case that both torque error and flux error are positive, the angle \u03b7 is obtained by the fuzzy logic estimator. In the other three cases, deflect angle can be derived simply as follows: If 0\u2265TE and 0\u2264\u03c8E , then \u03b7\u03c0\u03b7 \u2212= ; If TE <0 and \u03c8E <0, then \u03b7\u03c0\u03b7 += ; If TE <0 and 0\u2265\u03c8E , then \u03b7\u03c0\u03b7 \u2212= 2 Finally, the space angle of required space voltage vector is able to be calculated by formula (6)."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.22-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.22-1.png",
+ "caption": "Figure 2.22. A change of base point in a general motion of a rigid body.",
+ "texts": [
+ "28) shows that their vec tor sum is equivalent to a single angular velocity vector about a single instan taneous axis through the same base point. On the other hand, we may ask: What change, if any, occurs in co if the base point is shifted arbitrarily to another place in fJI? To answer this question, we let P be any point of fJI; and, for the same motion of fJI, we assume that at the same instant co and co* are distinct angular velocities of fJI about lines through distinct base points at 0 and 0*, respectively, as shown in Fig. 2.22. Since the velocity of any particle P, by its definition ( 1.8 ), is the same for every base point used in application of (2.27), using the vectors defined in Fig. 2.22, we may write for both 0 and 0* =v 0 .+co*xx* =(v 0 +coxr)+coxx*, (2.114a) (2.114b) (2.114c) wherein x = r + x*. However, with 0 as base point, it is clear that the term in parentheses in (2.114c) is equal to v a\u2022. Consequently, we have ( ro* - ro) x x * = 0. Since P is an arbitrary particle, this relation must hold for all x*; therefore, ro* = ro follows. In sum: The angular velocity vector is the same for every choice of base point associated with a rigid body. Let us recall, for example, the description in Fig",
+ " As a consequence of this invariant property of ro, (2.114) becomes =v 0 .+roxx*. (2.115a) (2.115b) The result shows that a motion of a rigid body due to a translation v 0 and a rotation ro about a base point 0 is equivalent to a rotation ro about any other base point 0* together with a new translation v0 \u2022 given by v0 \u2022 = v0 +ro x r, (2.116) where r = x- x* is the vector of 0* from 0. Thus, a change of base point cer tainly results in a change of velocity for the new base point, but the angular velocity of the body remains the same. (See Fig. 2.22.) Two additional easy theorems follow readily from (2.115). Their proof is left for the reader in Problem 2.70. (i) Invariant Projection Theorem. The projections upon the instantaneous axis of rotation of the velocities of all points of a rigid body are the same; that is, for all points P v P \u2022 a = v 0 \u2022 a, or v P \u2022 ro = v 0 \u2022 ro, (2.117) where a= ro/lrol is the instantaneous axis of rotation and 0 is any assigned base point. (ii) Parallel Axis Theorem. The velocity of a particle P due to a pure rotation with angular velocity ro about on axis a is equivalent to a rotation with Kinematics of Rigid Body Motion 125 the same angular velocity about\" a parallel axis together with a translational velocity perpendicular to that line, and conversely",
+ " Therefore, we may choose 0* to be at the shortest distance from 0 between the parallel lines so that r\u00b7ro=O (2.121) must hold. Then we form the vector product of (2.120) with ro, expand the result, and use (2.121) to obtain in terms of the originally assigned base point data the unique location r of the point 0* on the new parallel axis: (2.122) Thus, shifting the base point to 0* by using (2.118) in (2.1115) yields v P =pro+ ro x x*, (2.123) in which x* = x- r is the position vector of P from 0* on the new parallel axis. (See Fig. 2.22.) The equation (2.123) is the content of Chasles' theorem. It shows that the velocity of any particle P of a rigid body may be simply and uniquely charac terized by a rotation with angular velocity ro about a parallel line through a base point O* at the unique place r from 0 given by (2.122) together with a translational velocity (2.118) along that line. This is the motion typical of a nut moved along a threaded screw; it is reminiscent of the helical motion of a particle studied in Chapter 1. In fact, such a motion is known as an instan taneous screw motion; and the axis of rotation is named the screw axis"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000597_ac0006831-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000597_ac0006831-Figure1-1.png",
+ "caption": "Figure 1. Simplified diagrams showing (A) a disposable card-type flow cell detectors and (B) a disposable ion sensor. Key: (a) Perspex holder, (b) Ag/AgCl reference electrode for the organic phase, (c) Ag/AgCl reference electrode for the aqueous phase, (d) Aqueous electrolyte gel reference for the organic phase, (e) 2.8% (w/w) PVCNPOE organic gel layer, (f) Micro-photoablated 23-\u00b5m PET film containing PVC-NPOE gel in microholes, (g) plastic support, and (h) PET film.",
+ "texts": [
+ " The 2.8% (w/w) PVCNPOE gel was cast hot on the perforated PET film of the side exposing the smaller diameter. The gel filled the conical holes so that an array of microdisk interfaces could be obtained with a diameter of 22 \u00b5m exposed to the flowing aqueous solution The ionode was operated in a two-electrode mode using a pair of reference/counter electrodes.22 Flow System and Electrochemical Measurements. For experiments with flow conditions, a disposable card type of flow cell detector shown in Figure 1 was used. The easily removable disposable sensor shown in Figure 1B was produced by attaching the perforated PET film (23 \u00b5m thick) onto the plastic support and exposing to the analyte the smaller diameter of the hole array. The reference/counter electrode for the organic phase consisted of a tetrabutylammonium ion selective electrode (TBA+ISE) comprising an aqueous solution of TBACl gelified with 20% (m/ m) hydroxyethyl cellulose and a Ag/AgCl reference electrode. A TBA+ISE aqueous gel was added to the top of the composite polymer membrane having a total thickness of \u223c50 mm and covered with paraffin films, preventing the evaporation of water from the gel"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001575_1097-4628(20001121)78:8<1566::aid-app140>3.0.co;2-i-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001575_1097-4628(20001121)78:8<1566::aid-app140>3.0.co;2-i-Figure2-1.png",
+ "caption": "Figure 2 Coordinate system of tire.",
+ "texts": [
+ " Kamoulakos and Kao2 studied the transient dynamic responses of a tire rolling on a spinning drum with cleat. In the following section, we also show a finite element model of tire and cornering simulation of tire using implicit FEA code (ABAQUS/Standard) and explicit FEA code (ABAQUS/Explicit). Figure 1 shows a structure of the typical passenger car\u2019s radial tire. The tire is made of both rubber components such as cap tread and sidewall, and fiber-reinforced rubber components such as steel belt and textile carcass. Figure 2 shows an axis system for this simulation. A slip angle is an angle between direction of wheel travel and direction of wheel heading. A cornering force and a self-aligning torque characterize cornering ability of a tire. Direction of the cornering force is normal to direction of wheel travel. The self-aligning torque is moment around the axis in the direction of normal to road surface. Figure 3 shows an axisymmetric FE tire model, which is a passenger car\u2019s radial tire of 235/ 45ZR17. Rubber components are modeled by the continuous elements with hyperelastic material of Mooney\u2013Rivlin form"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003460_09544100g03204-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003460_09544100g03204-Figure1-1.png",
+ "caption": "Fig. 1 Missile airframe and dynamic variables",
+ "texts": [
+ " The design procedure for pitch-axis controller of tailcontrolled missile is presented in this section. The model employed in this analysis is based on the theoretical tail-controlled missile used as a base line for pervious non-linear control design [4, 26]. The missile model assumes constant mass, no roll rate, zero roll angle, no sideslip, and no yaw rate. Under these assumptions, the longitudinal non-linear equation of motion is reduced to two forces and one moment. Using body axis components (Fig. 1) these equations are Fx \u00bc QSCD (5) Fz \u00bc QSCN (6) My \u00bc QSdCM (7) The dynamic pressure is defined as Q \u00bc 1 2 rV 2 m \u00bc 0:7P0M 2 (8) Note that missile velocity and air density are not assumed to be constant or slow-varying, but a standard atmospheric model is assumed in simulations based on previously reported data [35]. Aerodynamic polynomials are given as CD \u00bc 0:3 (9) CN(a, d, M) \u00bc b1Na 3 \u00fe b2Najaj \u00fe b3N 2 M 3 a\u00fe dnd \u00bc cn(a, M)\u00fe dnd (10) CM (a, d, M) \u00bc b1Ma 3 \u00fe b2Majaj \u00fe b3M 7\u00fe 8M 3 a\u00fe dmd \u00bc cm(a, M)\u00fe dmd (11) The numerical values of the earlier equations are given in Table 1"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001127_s0022112002002483-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001127_s0022112002002483-Figure4-1.png",
+ "caption": "Figure 4. Two possible menisci between a solid and a liquid for a prescribed height of the triple point. Here, h0 > 0, and the initial angle of the meniscus with the vertical is \u03b80 and \u2212\u03c0\u2212 \u03b80, both satisfying (3.5). The two menisci merge when \u03b80 = \u2212 1 2 \u03c0, i.e. h0 = 2. The bent plates are introduced to illustrate the multiplicity of menisci for a given height of the triple point. The profiles of the menisci are computed based on the procedure outlined in \u00a7 3.4.",
+ "texts": [
+ " For example, a thin plate attached to an actuator in air can form the meniscus preventing the liquid from wetting the actuator, whereas the probe attached to the plate may be inundated (figure 3). 3.3. Uniqueness of the solution for the meniscus Proposition. For a prescribed admissible height, h0, of the triple point, there may be only two possible menisci. Proof. Let the prescribed non-dimensional height of the triple point L be h0 > 0 (i.e. only the positive solution in (3.5) is considered). Then \u03b80 < 1 2 \u03c0. Now, if \u2212 1 2 \u03c0 6 \u03b801 < 1 2 \u03c0 satisfies (3.5) then so does \u03b802 = \u2212\u03c0\u2212 \u03b801 (figure 4). Thus, the menisci, m01 or m02, starting with \u03b80 = \u03b801 or \u03b80 = \u03b802 increase \u03b8 from \u03b80 to 1 2 \u03c0 with increasing s. There are other angles < \u2212 3 2 \u03c0, such as \u03b803 = \u22122\u03c0 + \u03b801 that also satisfy (3.5), but a meniscus starting with \u03b80 = \u03b803 increases \u03b8 to \u03b8 = \u2212 3 2 \u03c0 as s \u2192 \u221e which results in a meniscus m03 identical to m01. Similarly, the meniscus with \u03b80 = \u22122\u03c0\u2212 \u03b801 coincides with m02. Thus, for a given h0 there are two distinct menisci. They merge into one when \u03b80 = \u2212 1 2 \u03c0 or h0 = 2 by (3.5), and we can view the two menisci as the two bifurcation branches with \u03b80 = \u2212 1 2 \u03c0 as the bifurcation point",
+ " The corresponding change in energy owing to the change of interfacial area at the edges is negligible compared to the change in the hydrostatic or the liquid\u2013vapour interface energies. We will thus evaluate the hydrostatic energy, EH , and the surface energy, ES , contributed by the liquid\u2013vapour interface only. Furthermore, the change in energy from the reference configuration where the meniscus height is zero is of interest. Thus, in what follows, EH and ES indicate the changes in energies per unit length of the plates from the reference configurations. If the plates are bent (e.g. figure 4) or thick, then the change in the solid\u2013liquid interface energy may not be negligible depending on the geometry and shape of the edges of the plates, and can be evaluated from the specific geometry. Here, for simplicity, we assume that such a change in the interfacial energy for the bent plates considered later is small compared to ES and EH , and hence the analysis, when applied to the bent plates, is restricted to geometries where the solid\u2013liquid interface energy change is small. The bent plates are introduced only to illustrate a bifurcation phenomenon in menisci"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003183_3.20488-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003183_3.20488-Figure1-1.png",
+ "caption": "Fig. 1 A multibody structure.",
+ "texts": [
+ " The first section describes the system configuration and geometry organization. In the second section a description of the modeling of a flexible body and detailed derivation of the kinematics are presented. The equations of motion derived via Kane's equations are given in Sec. III. In Sec. IV a simulation of a space robotic system is presented. The conclusion forms the last section. II. System Description The system is composed of rigid and flexible bodies forming a treelike structure as shown in Fig. 1. The bodies are interconnected by joints that have three rotational and three translational degrees of freedom. The flexible bodies in the system are modeled by beams undergoing small deformations in all directions. The beam may have variable cross-sectional area along its length with the restriction that the principal axes at each cross-section are parallel. For simplicity the shear center is assumed to coincide with the centroidal axis. In the formulation of the equations of motion, all bodies will be considered flexible",
+ " (A10) in Appendix A, and assuming small rotations due to deformation, it can be expressed as where and (is) ( 19) where vjm and ^m are the partial angular velocity arrays associated with c5^ and qp9 respectively. In Eqs. (18) and (19), Bk and Ck are Boolean matrices used for describing the indices of cbk in c5r and r\\k in f/r, respectively, defined as In a more compact form, Eq. (17) can be written as where (20) (21) The partial angular velocity arrays are functions of displacements only and need to be generated for each element i in body A:. Consider an element / in B4 in Fig. 1. Let each body have c modal coordinates. The angular velocity of n 4| is (22) In the subsequent analysis the angular velocity of nk with respect to 11\u00b0 and the angular velocity of iik* with respect to 0, denoted as cok and o**, respectively, are also needed. The cok can be obtained by subtracting nk\u00bbki from Eq. (13) (23) where fik m is obtained by setting the last term in Eq. (19) to zero. Similarly, cok* can be obtained by subtracting from cok. This yields con (24) Similarly, from Eq. (7) the angular velocity of the element i relative to nk can be written as (15) Substituting Eqs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001127_s0022112002002483-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001127_s0022112002002483-Figure2-1.png",
+ "caption": "Figure 2. (a) A family of menisci formed between a hydrophilic solid plate and a liquid is shown for different prescribed heights of the plate. The contact angle \u03c6 between the tangent to the solid surface and the menisci is constant, but the angle, \u03b80, of the meniscus with the vertical at the triple point, L, changes as L moves from the bottom surface of the plate towards the top with the displacement of the plate towards the liquid. The local normal, n\u0304, to the plate surface rotates from vertical down to vertical up. Among all the members of the family, m2 offers the maximum capillary force \u03b3 (per unit length of triple line) vertically downward. When the plate is lowered into the liquid, m5 is the highest possible meniscus attainable prior to collapse that offers an upward vertical force \u03b3 sin\u03c6, a fraction of \u03b3. (b) Similar menisci for a hydrophobic solid. (c) The coordinate system used to define the meniscus. All the profiles of the meniscus shown in (a)\u2013(c) are computed based on the procedure outlined in \u00a7 3.4.",
+ "texts": [
+ " (ii) All interfaces are smooth and the local asperities are ignored. Similarly, no local pinning point occurs as the line L advances along a solid surface. (iii) The solid plates are long normal to the paper, but they have a finite width. The heights of the meniscus at all points along its length are equal. Thus, the problem is one-dimensional and the meniscus has only one non-zero principal curvature. Consider a long thin rigid strip of a hydrophilic solid (\u03c6 < 1 2 \u03c0) on the surface of a liquid. Its cross-section at the edge is shown in figure 2(a). For illustration, the plate is assumed symmetric about its vertical axis, and its edge is represented by a semicircle. The outward normal at any point of the boundary is n\u0304. When brought into contact with the liquid surface, the liquid spreads over the entire bottom of the plate and forms a meniscus. That such a spreading cannot be partial, at least for a circular disk, is shown mathematically by Vogel (1982). If the plate is moved upward, away from the liquid surface, the meniscus takes a form such as shown by m1 which forms an angle \u03b80 with the vertical (positive downward) at L",
+ " In the latter case, symmetry in the meniscus breaking forces will be restored. Thus, in the absence of hysteresis, \u03c6 < 1 2 \u03c0 and geometric constraint (horizontal top) give rise to asymmetry. The presence of hysteresis can only reduce the asymmetry (reduce the difference in the meniscus breaking forces), but cannot alone explain the asymmetry. In the rest of the paper, contact angle hysteresis is assumed negligible. The sequence of menisci for a hydrophobic plate (\u03c6 > 1 2 \u03c0) for its various heights is shown in figure 2(b). Here, no meniscus is formed when the plate is moved away from the liquid surface. In order to estimate the force prior to collapse in the experiment of figure 1, we estimate from the micrographs the average angle of the meniscus at the triple points with the vertical as \u03b80 = 24\u25e6 and 130\u25e6 corresponding to removal and submersion. Then, with \u03b3 = 0.072 J m\u22122 for water, and with a perimeter of 240 \u00b5m, the forces for removal and submersion are found to be 15.8 \u00b5N and 11.1 \u00b5N, respectively. The corresponding experimental values are 12",
+ " In other words, a small enough solid plate, hydrophilic or hydrophobic, no matter how dense it is, can float in any gravitational field, as long as the radius of curvature of the solid surface is larger than rc, the radius of the core region of the triple point. It is, however, worth noting that circular thin plates are difficult to fabricate when micro mechanical systems are formed by deep etching (such as deep silicon etching) or by filling a mould. A mathematical model is provided next. 3.2. Mathematical modelling We start by setting up the coordinates shown in figure 2(c). The triple point, L, is the origin, Y denotes the vertical axis (positive downward), S is the coordinate along the liquid\u2013vapour interface, \u03b8(S) is the angle that the tangent to the interface makes with the vertical at S . For the one-dimensional meniscus, the Young\u2013Laplace equation (equation (2.2)) can be represented as d\u03b8 ds = h0 \u2212 y with \u03b8(s = 0) = \u03b80, (3.3) which has been non-dimensionalized by the capillary length l0 = \u221a \u03b3/\u03c1g. Here, in reference to (2.2), 1/R1 = d\u03b8/dS , 1/R2 = 0, \u2206p = \u03c1g(H0\u2212Y ), the hydrostatic pressure assuming that the atmospheric pressure does not change with the small height of the meniscus, \u03c1 is the density of the liquid, and S = sl0, H0 = l0h0 and Y = l0y",
+ "5) where \u03b20 = 1 4 \u03c0 \u2212 1 2 \u03b80. h0 is positive when \u2212 3 2 \u03c0 6 \u03b80 6 1 2 \u03c0 or 0 6 \u03b20 6 \u03c0, and h0 is negative when 1 2 \u03c0 6 \u03b80 6 5 2 \u03c0 or \u2212\u03c0 6 \u03b20 6 0, i.e. the sign of sin \u03b20 is similar to that of h0, which is the reason for introducing the angle \u03b20. Equation (3.5) implies that h0 = H0/l0 can vary between \u22122 and +2 for all solids (hydrophilic and hydrophobic) and liquids under any gravity. For a given \u03c6, the geometry of the edge determines the possible range of \u03b80 and hence h0. For the flat plate of figure 2(a, b), \u03b80 can vary from \u2212( 1 2 \u03c0 \u2212 \u03c6) to ( 1 2 \u03c0 + \u03c6). If the edge is circular then the range increases, although the contact angle (\u03c6) remains the same. Thus, a hydrophilic or a hydrophobic solid can be designed to contact a liquid surface and move into the liquid without submerging itself, which offers micro actuators considerable flexibility for manipulating objects in liquids with a probe. For example, a thin plate attached to an actuator in air can form the meniscus preventing the liquid from wetting the actuator, whereas the probe attached to the plate may be inundated (figure 3)",
+ " Here, for simplicity, we assume that such a change in the interfacial energy for the bent plates considered later is small compared to ES and EH , and hence the analysis, when applied to the bent plates, is restricted to geometries where the solid\u2013liquid interface energy change is small. The bent plates are introduced only to illustrate a bifurcation phenomenon in menisci. 5.1. Energy for the meniscus formed by a single plate Consider a small element of the meniscus (liquid\u2013vapour interface) of length dS at an angle \u03b8 with the vertical (figure 2c). Its horizontal projection is dX = dS sin \u03b8. Then the liquid\u2013vapour interface energy of the element before and after formation of the meniscus is \u03b3dX and \u03b3dS , respectively. The elementary change in energy, dES = \u03b3(dS \u2212 dX) = \u03b3l0(1\u2212 dx/ds)(d\u03b8/\u03b8\u2032), and ES E0 = 2 \u222b \u03c0/2 \u03b80 (1\u2212 sin \u03b8) d\u03b8 \u03b8\u2032 = 2 \u222b 0 \u03c0/4\u2212\u03b80/2 \u22122 sin \u03b2 d\u03b2 = 4(1\u2212 cos \u03b20), (5.1) where \u03b2 = 1 4 \u03c0\u2212 1 2 \u03b8, \u03b20 = 1 4 \u03c0\u2212 1 2 \u03b80, E0 = l0\u03b3, the factor 2 outside the integral accounts for the two menisci on either side of the plate, and \u03b8\u2032 is defined by (3",
+ " It is contributed by the liquid column under the plate and the column of the liquid under the liquid\u2013vapour interface. The former gives an energy EH1 = \u03c1gH2 0W = \u03c1gl30h 2 0w = E0h 2 0w where H0 is the height of the column under the solids surface, 2W is the width of the plate, w = W/l0 and h0 = H0/l0. The contribution of the liquid column under the liquid\u2013vapour interface can be evaluated by considering a small segment of the interface dS with column height H(S). The energy due to the elementary column is dEH2 = 1 2 \u03c1gH(S)2dX, where dX is the horizontal projection of dS (figure 2c). From (3.3), \u03b3(d\u03b8/dS ) = \u03c1gH(S) giving H(S) = l20(d\u03b8/dS ) = l20(d\u03b8/l0ds) = l0\u03b8 \u2032. Thus, EH2 = 2\u03c1g \u222b \u221e 0 1 2 H2 dX = \u03c1g \u222b \u03c0/2 \u03b80 l30\u03b8 \u2032 sin \u03b8d\u03b8 = 2E0[\u2212 2 3 + cos \u03b20 \u2212 1 3 cos(3\u03b20)], (5.2) where the upper limit \u03b8 = 1 2 \u03c0 is arrived at as s \u2192 \u221e. Note that EH2 accounts for the hydrostatic energy of the meniscus on both sides of the plate. The total energy, E = ES + EH1 + EH2, normalized by E0, is given by E E0 = 8 3 + wh2 0 \u2212 2 cos \u03b20 \u2212 2 3 cos(3\u03b20). (5.3) Note that E = 0 when \u03b80 = 1 2 \u03c0 and H0 = 0, i"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000796_s0947-3580(01)70939-9-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000796_s0947-3580(01)70939-9-FigureI-1.png",
+ "caption": "Fig. I. Geometry of scale model autonomous helicopter.",
+ "texts": [],
+ "surrounding_texts": [
+ "Consider Fig. 1. LetI = {Ex, Ey , Ez} denote a right hand inertial frame. Let the vector ~ = (x,y,z) denote the position of the centre of mass of the helicopter relative to the frame I. Let A = {EY,E2,E3} be a (right-hand) body fixed frame for the helicopter. The orientation of the helicopter is given by a rota tion R : A ----t I, where R E SO(3) is an orthogonal rotation matrix. The angular velocity of airframe with respect to the body fixed frame is denoted n while the angular velocity of the rotor blades around axis Adaptive Compensation of Aerodynamic Effects 45 of rotation is denoted 'W. Note that the position of the rotor blades is irrelevant and only the angular velocity of the blades is considered. Let m E lR denote the mass of the helicopter and I E lR3x3 denote the constant inertia matrix around the centre ofmass (with respect to the body fixed frame A). The dynamics of the helicopter airframe are modelled as rigid body motion [2,22,24] where sk(n) is the skew symmetric matrix associated with the vector product n x u = sk(n)u. The vector FE I combines the principal non-conservative forces applied to the helicopter airframe including main rotor thrust Tand drag terms associated with the rotor wake on the airframe (cf. Eq. (10\u00bb. The term ~ denotes the modelling error in the linear force input and r denotes the external torque applied to the airframe. Some brief comments on the nature of these terms are given below. For a detailed discussion of helicopter aero dynamics the reader is referred to any standard text on helicopter design (cf. for example [22]). Torque inputs r: Control input for the attitude dynamics is obtained via the tail rotor collective pitch and cyclic pitch input to the main rotor. Cyclic pitch inputs lead to a tilting of the rotor disk relative to the airframe and hence an inclination of the principal thrust component of the lift that, due to the offset between the rotor hub and centre of mass of the air frame, results in a torque input to the airframe attitude dynamics. The aerodynamic balance of the rotor disk is highly susceptible to local wind conditions and its tilting motion is strongly influenced by wind gusts and deformation of the rotor wake. Stabilisation of the attitude dynamics of a scale model autonomous heli copter (or indeed any helicopter) is a difficult problem. This is especially true when the helicopter enters the ground effect zone in which the rotor wake interacts with the earth's surface causing random wind gusts, the formation of vortices I and dynamic inflow reso nance effects [4,20]. These complex aerodynamic dis turbances tend to affect the roll and pitch stability of the helicopter first and lead to significant perturbation of the linear dynamics only if the motion of the heli copter tends towards instability. The stabilisation of ~ = v, mv = F + mge3 + ~, R= Rsk(n), H1= -n x In+r, (1) (2) (3) (4) the attitude dynamics is not the subject of this paper and we assume that a suitable low level robust stabilis ing control is implemented that satisfactorily regulates the torque inputs r. The torque input Ta used in the control design may be thought of as time-varying set point for the fast dynamics of the low level control. In the theoretical development we assume that r = Ta in order to focus on the adaptive control algorithm. In Section 4 the robustness of the proposed algorithm is simulated with a noise-like disturbance added to the actual torque inputs r = Ta + v(t). The disturbance v is chosen to model the types of input disturbances that may be encountered due to the complex aerodynamic effects mentioned above. Perturbation to the linear force input: Apart from some negligible noise effects the perturbation ~ incorpo rates an important dynamic coupling between the alti tude and linear dynamics. The expression used in Section 4 (Eq. (59\u00bb to model ~ for the robustness simulation corresponds to the form used in contem porary works [10,12,29]. The coupling leads to weakly non-minimum phase zero dynamics [10] that are qua litatively similar to those encountered for the original investigation of the VTOL [6]. Unlike the VTOL [17] the system is not differentially flat [12,15,29]. As a con sequence (to the best of the authors knowledge) there is no control design available that deals with the full non linear dynamics of the accepted model. The approach taken in prior control algorithms [2,3,16,25,26,31] is to design a robust controller for the system where ~ == 0 and analyse the robustness of the closed loop system with respect to the perturbation ~. We take an analo gous approach in the present paper. The focus of the present investigation, however, is on robustness and adaptation with respect to inaccuracies in modelling the force F; a different problem to that of robustness with respect to ~, and not one that has been considered in previous works. For this reason, and in the interest of a less complicated presentation, we analyse only the dynamic model Eqs (1)-(4) where ~ == 0 in detail and leave further discussion of the dynamic perturba tion ~ until Section 4. The dynamics of the main rotor disk around its axis of rotation is a decoupled system independent of its tilting motion. The torque exerted by the helicopter engine Te is transmitted via a flexible coupling to the rotor blades. The engine torque is opposed by an aerodynamic drag QM. The dynamic of the angular velocity of the disk is (5) I A discussion of this effect is given in Prouty [22, p. 138] for the case of forward flight. Local wind and uneven ground can generate this situation in hover conditions. where I M is the moment of inertia of the rotor disk around its axis. Lead-Iag motion of the rotor blades is negligible in this analysis. 46 R. Mahony and T. Hamel The lift and drag generated by the main rotor is directly affected by two input controls: The collective pitch that is the angle of the rotor blades with respect to the plane of the rotor disk, controlled by regulating the elevation of the swash plate, and the velocity of the rotor blades, controlled by regulating the throttle to the engine. As a first approximation the total thrust Tmay be approximated as [22, p. 15] the principal control input for the thrust T. Fix () to be a constant value such that the thrust generated at the nominal operating condition supports the helicop ter in hover. Dividing through Eq. (8) by w 2 and com pleting the square for vT/w one obtains (9) where VM 4> ~ tan(4)) =-, wrM (10) where b > 0 is an unknown parametric error. An important observation is that the sign of the constant b is known. Recalling the discussion following the model Eqs (1)-(4) the aerodynamic torque inputs applied to the airframe using the cyclic and tail rotor control inputs are r ~ - (Tt 2 3) ~ Ta - a,Ta,Ta \u00b7 Air resistance on both the rotors generate anti-torques applied to the airframe acting through the hub of the respective rotor (independent of the orientation of the actual rotor disk). With the collective pitch fixed to a constant value the air resistance on the main rotor blades is proportional to the square of the angular velocity of rotation of the rotor blades. Thus, one may write (cf. Eq. (5)) where dM , dT are unknown constants. The tail rotor and main rotor are mechanically coupled in all scale model autonomous helicopters resulting in the direct dependence of the tail rotor drag on w 2. The final tor que contribution to the airframe dynamics comes from the reactive torque exerted on the airframe by the motor. This torque is equal and opposite to the engine torque applied to the main rotor dynamics. may be thought of as an unknown parametric input uncertainty. The total force applied to the airframe in direction E'3 is (to a first approximation) F= (T-D M )E'3, where DM = CDMPV~ [22, p. 7] is the drag due to the rotor wake on the helicopter airframe (CDM is the drag coefficient of the exposed airframe times its surface area). The drag is proportional to the thrust T due to the quadratic dependence on the down-flow velocity VM (Eq. (7)); thus (noting that E} = Re3 one may write) (7) (6) where a small angle approximation is used for 'tan' vM is the down-flow velocity at the main rotor while wrM is the effective forward velocity of the rotor tip in the plane of the rotor disk. For hover condition in the absence of the ground effect the down-flow velocity"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0000595_1.2828771-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000595_1.2828771-Figure3-1.png",
+ "caption": "Fig. 3 The instantaneous screw axis",
+ "texts": [
+ " How ever, low contact ratio and load capacity limit the application and working life of crossed helical-gears. In the theory of gear ing, two meshing surfaces in crossed axes are hyperboloids and the contact line is a screw axis (Litvin, 1989). In order to increase the contact ratio and load capacity of the crossed heli cal-gear, a novel type named Helipoid gears is proposed based on the concept of two meshing hyperbolids. Consider that the equations of the instantaneous screw axis MN, as shown in Fig. 3, are known. The axis of screw motion may be represented by the following equations: (32) Journal of Mechanical Design MARCH 1997, Vol. 1 1 9 / 1 1 1 Downloaded From: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 01/30/2016 Terms of Use: http://www.asme.org/about-asme/terms-of-use where b = \\OfM\\ and \u20ac = \\MN\\. The matrix representation of the hyperbolid represented in coordinate system Sf( Xf, Yf, Zf) is expressed by cos ifi sin (f 0 -sin ifi 0 cos ip 0 0 1 (33) Because the path of the hob cutter is parallel to the axial section of the hyperbolid, angle y can be obtained by considering Eqs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001477_6.2001-4160-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001477_6.2001-4160-Figure2-1.png",
+ "caption": "Figure 2. Missile Coordinate System",
+ "texts": [
+ " Sample engagement scenarios with a nonmaneuvering target will be given to illustrate integrated guidance-control system performance. 2. Missile Model A six degree-of-freedom nonlinear dynamic model of an air-to-air homing missile is employed in the present research. The missile is controlled using four tail-mounted fins, and includes the logic to distribute the pitch, yaw, and roll commands to the appropriate fins. The missile equations of motion are expressed in the body coordinate system XB? YB, ZB illustrated in Figure 2. D ow nl oa de d by B IB L IO T H E K D E R T U M U E N C H E N o n A ug us t 3 , 2 01 3 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /6 .2 00 1- 41 60 Successful operation of the missile requires it to approach the target as close and as parallel as possible, while maintaining a specific roll orientation with respect to the target. The equations of motion used in the present research are: p= \u2014 q=M ^~ /zV I* ' Iy Iy I _ _ \\ Nr = \u2014 - u = xci x\u2014\u2014\u2014 m \u00ab yci vi?v = \u2014 \u2014\u2014\u2014 \u2014-ur + wp, m zg \u2014 m -vp + uq In the above equations, u, v and w are the velocity components measured in the missile body axis system"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001833_1.2916914-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001833_1.2916914-Figure6-1.png",
+ "caption": "Fig. 6 Impact of a slider-crank mechanism with a free-block",
+ "texts": [
+ "C( Y) ,C(Z),0,0,0, - C(X), - C( Y), - C ( Z ) ,0 ,0 ,0] , where ciX), C(Y)> and c(Z) are the components of c in the XYZ reference frame. Different coefficients of restitution were con sidered to represent the energy loss in the collision of the two spheres as the system experienced multiple impacts. The motion of pendulum 1 is shown in Fig. 5 for a restitution coefficient of 0.5. As a second example, the impact between the slider of a slider-crank mechanism and another sliding block is considered [6]. A schematic representation of the system is shown in Fig. 6. Physical data for this example are provided in the Appendix. If a set of Cartesian coordinates is employed to describe the configuration of the system, then the system is kinematically constrained. The constraint equations correspond to the pris matic and the pin joints connecting different components. The slider-crank is driven by a restoring torque such that the crank maintains almost a constant angular velocity. At some instant, the slider impacts a free block which is inertially driven to the left at a constant speed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002608_physreve.67.011710-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002608_physreve.67.011710-Figure1-1.png",
+ "caption": "FIG. 1. Illustration showing bookshelf vFLC smectic layers, the orientation of the FLC dipoles P, and the director/index ellipsoid axis c.",
+ "texts": [
+ "com 1063-651X/2003/67~1!/011710~12!/$20.00 67 0117 stiffened, yet the strength of the electrostatic effect is not so large that surfaces can be neglected. To account for this, simple models for surface anchoring forces have been added to the electrostatic model. The resulting dynamical equation has been used to numerically simulate vFLC switching and the result is compared to the dynamic response of a high-PS smectic-C* FLC cell. The computed vFLC switching time constant was found to be close to the measured value. Figure 1 is an illustration of the surface stabilized smectic-C* bookshelf structure ~suppressed helix!, in which the FLC molecules organize themselves into sheets ~smectic layers!. The FLC molecules\u2019 electric dipoles are confined to rotate within the smectic planes, while the molecule\u2019s long axes (; the director! are constrained to tilt away from the layer normal by a fixed angle u . This is also the direction of the optical index ellipsoid\u2019s extraordinary axis. As the director rotates through the angle f around the layer normal \u00a92003 The American Physical Society10-1 ~driven by an applied electric field E), the projection of the index ellipsoid onto the cell face changes, causing the cell\u2019s optic axis to rotate",
+ " The retardation G of the wave plate is a function of the index ellipsoid\u2019s ordinary and extraordinary indices of refraction no and ne , and of the angle c which denotes the degree to which the index ellipsoid\u2019s c axis tilts out of the plane of the cell @16#: G~c!5 2p@ne~c!2n0#L l , ~29! 1 ne 2~c! 5 sin2c n0 2 1 cos2c ne 2 . 0-8 The angles Q and c are related to the dipole orientation and FLC tilt angle u through the following relations: tan Q57tan u sin f , sin2c5cos2f sin2u . ~30! The (2) sign applies if the c director is clockwise from P as illustrated in Fig. 1, the (1) sign applies if it\u2019s counterclockwise. The standard configuration for viewing V-shaped switching is to place the vFLC cell between crossed polarizers such that the cell\u2019s z axis is parallel to the polarization state of incident light. The intensity of light transmitted by this assembly is I5I0sin2@G~c!/2#sin2~2Q!. ~31! In order to compare the models to a test cell, we need to know the FLC\u2019s values of PS , h , and \u00abF , and we need to know the cell\u2019s values for tA , \u00abA , and tF . The test cell\u2019s alignment layer was nylon-6 with tA51962 nm ~profilometer measurement",
+ " The ratio of Debye screening length to jP might be at least a crude measure of how 011710 important ions are. That ratio is estimated to be around 10 for the cell studied here, suggesting that ions might have had only a small effect. However, a better analysis is needed. This work was funded by the DARPA Liquid Crystal Agile Beam Steering program under Contract No. DAAH01-97C-0139 with the Rockwell Scientific Company. The author thanks Noel Clark, Mark Handschy, Michael Meadows, and Michael Wand for helpful discussions. Figure 1 is based on an illustration provided by Noel Clark. The FLC cells were built by Chris Walker who also measured alignment layer thicknesses. The FLC was supplied by Michael Wand. With the inclusion of dielectric anisotropy the torque equation @Eq. ~3!# becomes @19# h df dt 5EFPScos f~12a sin f!, ~A1! a[ D\u00abEF PS sin2u . This is the same as Eq. ~3! except for the term proportional to D\u00ab . Next substitute Eq. ~2! for EF into the expression for a: a52 D\u00ab \u00abF~f! V/VS1sin f 11 \u00abA \u00abF~f! tF 2tA sin2u . ~A2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002580_robot.2003.1241777-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002580_robot.2003.1241777-Figure1-1.png",
+ "caption": "Figure 1 : HRP-2L",
+ "texts": [
+ " For running pattern generation, we introduce a new method nsing precise physical parameters of a robot. Aft,er discussing a hopping pattern for less power consumption, we show a realistic running under the consideration of the actuator limits. 2 Humanoid Model To build a running humanoid with conventional actuators, we must makei t as light as possible. However, there is a physical and technical limitation for weight saving. Therefore we decided to set the model parameter based on the specification of an existing humanoid robot. 0-7803-7736-2/03/$17.00 02003 IEEE 1336 2.1 HRP-2L HRP-ZL(Figure 1) is a biped robot that was developed in the Humanoid Robotics Project(HRP) of t,he Ministry of Economy, Trade and Industry of Japan[lO]. Table 1 shows the specification of HRP2L, and Table 2 shows the specification of leg actuators. HRP-2L has batteries and dummy weights, and these elements can be easily removed. Removing them and considering the little increase of weight for optional equipment for running, we assume that weight of HRP-ZL will be reduced to 30[kg]. This is about one-fourth of the HRP-l weight:117[kg]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.19-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.19-1.png",
+ "caption": "Figure 2.19. A simple spatial mechanism.",
+ "texts": [
+ " The analysis of spatial motions, because of the increased complexity and the difficulty of visualizing the geometrical aspects of a problem, inherently is more difficult; but the use of vector methods in these applications often simplifies their analysis and eliminates our need to perceive all of the geometrical details. The application of vector methods to the solution of spatial problems demonstrates strikingly the power and utility of this invaluable analytical tool. This is illustrated clearly in the following example of a simple spatial mechanism. Numerous additional exam ples will be encountered in Chapter 4. Example 2.9. Two slider blocks A and B are connected by ball joints to a rigid rod, as shown in Fig. 2.19. The motion of A in cP = { F; ik} is controlled so that its translational velocity is constant during an interval of interest. Find 118 Chapter 2 in cP the translational velocity and acceleration of B, and determine the angular velocity and the angular acceleration of the rod in the interval of con cern. Assume for simplicity that the ball joints are centered on the axes of the slider guide shafts, and suppose that the joints are ideally smooth so that the rod suffers no angular velocity about its own longitudinal axis. What will be the effect on the rotation of the rod if the ball joint at B is replaced by a hinge pin and yoke assembly? Solution. The translational velocity of B is given by (2.27). We write v B = ik = v Bk = v A +(I) X I, (2.91) wherein the constant translational velocity of A is VA= yj = VAj (2.92a) and I= -ai - yj + zk, (2.92b) the vector of B from A, is obtained from the geometry shown in Fig. 2.19 for points on the axes of the guide shafts. Of course, (2.93) relates z and y. Differentiation of (2.93) yields 2zi + 2yy = 0, and use in this expression of the component relation from (2.92a) gives the translational velocity of B in cP. I.e., in (2.91 ), we now have (2.94) Kinematics of Rigid Body Motion 119 Moreover, because this equation is valid for all times in the interval of interest, the translational acceleration of B in r:f> may be obtained most easily by differentiation of (2.94 ). With the aid of (2",
+ " The angular velocity and angular acceleration of cp relative to tP at time t0 are given by ffi = 4e 1 + 2e2 - 3e3 rad/sec, Compute the first and second time rates of change of X as seen from cp at the instant of interest. Does v 0 affect the results? .w Problem 4.6. I, 320 Chapter 4 4.7. Consider the hinged joint and slider block shown in Fig. 2.20. Let frame 1 = { B; p, y, k} be fixed in the slider block B, as shown, and introduce another frame 2 = { B; a, p, A} fixed in the hinged yoke of the connecting rod AB so that A is parallel to!. (a) Determine as functions of y the angular velocity of the rod relative to B and the absolute angular velocity of B in the frame t:P = { F; ik} shown in Fig. 2.19. (b) What is the angular speed of the rod relative to the slider block? (c) What is the absolute angular velocity of the rod referred to frame 1? 4.8. Two gears A and B are held in rolling contact by a link of length I between their centers. The gear A rotates with an angular velocity OJ A relative to the fixed frame t:P = { 0; i, j }, while the gear B moves around the periphery of A with an angular velocity OJ B relative to t:P. Find the angular velocity of each gear relative to the link. Problem 4"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0002434_0022-4898(91)90017-z-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002434_0022-4898(91)90017-z-Figure5-1.png",
+ "caption": "FIG. 5. At tachment of T-shaped sensors.",
+ "texts": [],
+ "surrounding_texts": [
+ "362 Y. NOHSE et al.\ncalculated f rom the moments of the L-shaped sensors using the equations:\nf = V ' { ( M 2 - M1)/ l l} 2 + {(M3 - M4)//14 + W} 2 (1)\n0 = COS -1 {M2 - M1)/(Fl l )} (2)\nR = {M1 + W ( l + l 3 + 14)}/{F - Lcos (o l - 0)} (3)\nwhere W is the net weight of the wheel system, M1, M2, M3, M4 are the moments measured by the strain gauges 1, 2, 3, and 4, respectively in the L-shaped sensors, I 1, 12, 13, 14, are the distances between the gauges and l is the horizontal distance between the position of gauge 4 and the center of gravity of the net weight of the wheel system. L is the distance f rom gauge 1 to the centre of the wheel, and c~ is the angle between the vertical beam and the straight line connecting these points.\nIn order to check the accuracy of the measurement , the minimum distance R ' f rom the center of the wheel to F was also calculated by\nR ' = T / F (4)\nwhere T is the wheel axle torque.\n(2) Torque. The axle torque of the wheel was measured by a pair of cross strain gauges.\n(3) Rotation angle. The rotation angle of the wheel was measured using a rotational potent iometer attached to the wheel axle.\n(4) Sinkage. The sinkage of the wheel was measured using a linear potent iometer .\n(5) Traveling distance. The traveling distance of the wheel was measured using a linear potent iometer .\n(6) Distribution o f the soil reaction. The normal and tangential stresses of the soil reaction were measured using T-shaped sensors [8, 9] (see Figs 5 and 6). Two groups of three T-shaped sensors (136 m m width each) were used in order to detect the variation of the stresses due to the travelling of the wheel and also the differences between the stresses in the central part and in the two outside parts of the wheel. The first group of three sensors was located where it would face the soil surface in the initial stage of rotation and the second group where it follows 180 \u00b0 later. The",
+ "Strain gauge 50\ncomparisons between the drawbar pull and the contact load measured using L-shaped sensors and those using T-shaped sensors are discussed in the following section.\n(7) Soil deformation. A new method for measuring soil deformation was developed, which uses markers of 25/zm semitransparent polyester film of 5 mm in diameter. One side of each marker had an imprinted black cross, and the reverse side was coated with adhesive. A dab of silicon rubber sealant was applied to the adhesive side, and also sand was sprinkled over it so that the markers would move in accordance with the displacement of soil particles. The markers, a few hundred in number, were wetted in the non-adhesive sides and applied to the inside surface of the acrylic wall at appropriate intervals (Fig. 7), and then the soil bin was filled with",
+ "364 Y. NOHSE et al.\nsand. Photographs of the markers were taken at regular time intervals, and from these the (x, y) coordinates of the centers of the markers were read by a digitizer and transmitted directly to the computer.\nStrain (Cauchy's infinitesimal strain) in the triangular elements formed by the centers of three mutually adjacent markers was calculated in the same manner as in the finite element method. The displacements of the centers of the markers were automatically depicted using computer graphics [10-12].\n(8) Measuring system. Data from all sensors was input to a multi-channel data logger (scanning speed 100 msec/CH) with an analogue-to-digital converter and then transferred to the computer via a GPIB. Mechanical quantities (1)-(7) were analysed and displayed graphically on the on-line computer system. The whole measuring system of the test apparatus is schematically depicted in Fig. 8.\nMeasured curves for each of the basic mechanical quantities of the traveling performance at 16.22% slip are shown in Fig. 9 as an example.\nAt slip within the range from 0 to 15% the drawbar pull increased monotonically to a stable value. With slip higher than 15% the drawbar pull increased to a peak value, decreased to a minimum value, and then recovered to a plateau with some oscillations. This phenomenon became more pronounced as slip increased.\nThe use of the linear bearings, with a frictional resistance between +5% of the contact load in the tests enabled the contact load to be maintained constant.\nThe torque curve showed oscillations synchronous with those in the drawbar pull curve.\nThe sinkage increased with the wheel rotation, gradually approaching a constant value, except when slip approached 100%.\nThe normal and the tangential stresses are the mean values of those detected by the three T-shaped sensors in each group. The peak normal stress measured by the second group was lower than that by the first one due to the increased contact surface area resulting from the increased sinkage as the rotation proceeded.\nThe relation of the maximum and mean drawbar pull to slip are shown in Fig. 10. \"Mean drawbar pull\" is the mean value during the period following the termination of output from the first group of T-shaped sensors and prior to the commencement of output from the second group, i.e. the range of almost 180 \u00b0 in rotation angle in a steady state."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003263_004051758805801102-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003263_004051758805801102-Figure3-1.png",
+ "caption": "FIGURE 3. Distribution of fiber cross section into class intervals.",
+ "texts": [
+ " (4) The distance of the center of the chord from the yam axis is x*=rcoscp , ( 5 ) The area is The area s(r) of the darkly outlined portion can be obtained from Equations 6 and 7: ~ ( r ) = ( r cos ~p - rj)V(d/212 - ( r cos ~p - rj)2 + r2 rcoscp- d / 2 t (d/2)* cos-I nd * (8) X (cp - sin cp cos cp) + - 8 where cp is given by Equation 4. Now let the cross section of Yarn be divided into annular rings of equal width h, such that thejth class interva1,j = 1 , 2 , . . . , is defined by the Smaller distance = h ( j - I ) and larger radial distance rj = hj. Consider a fiber, the cross section of which falls into five class intervals, ( j + 1) to ( j + 51, as shown in Figure 3. In the ( j + 1)th class interval, the area of the fiber is .T(Q+~), and in the (i i- 2)th class interval, the arm of the fiber is s(rj+2) - drj+t), etc. Similarly, in the ( j + 5)th class interval, the area of the fiber is S(r, + 4 2 ) - s(r,+,) = *d2/4 - s(r,+d). So by using Equation 8, we a n C ~ I - at Bobst Library, New York University on June 5, 2015trj.sagepub.comDownloaded from NOVEMBER 1988 629 culate the area of the fibers lying in the different class of the cross section. The ratio of the area of fibers in intervals"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002366_fuzzy.1998.687523-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002366_fuzzy.1998.687523-Figure1-1.png",
+ "caption": "Figure 1. Active magnetic bearing setup",
+ "texts": [
+ " Theorem 4 minimize y over Q = QT and Y,, subject to the following LMI constraints (uJi -Q4T+Bg. i .r .r . -71 B2 0 \"') -71 < q20) A,Q+QA~+BI;Y,+Y~BT, , 2 I < qal) -yI 0 CQ 0 -71 Q > q23) Given a solution (Q, Yi) of this minimization problem, the optimal H, state feedback gain is obtained as 4 Application to an Active Magnetic Bearing (AMB) System 4.1 AMB System The experimental setup which will be used is a t w e axis controlled vertical shaft magnetic bearing with 'a symmetric structure. An outline of this system is d e picted in Fig. 1. Due to the small gyroscopic effect of this setup [$I, the system can be divided into two identical subsystems (x-z and y-z planes). Thus, without loss of generality, we will focus our analysis strictly on the x direction motion only. The equations of motion for the AMB including harmonic disturbance can be represented as [8]: where x1 denotes the displacement of the rotor from the center position, x2 is the velocity, and i, is the control input current applied to the electromagnets. The harmonic disturbance w(t) created by the unbalance of the rotor is of the form w(t) = ap2 sin@) (26) where a denotes the unbalance parameter and p is the rotational speed of the rotor"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001397_70.897776-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001397_70.897776-Figure4-1.png",
+ "caption": "Fig. 4. Prototype parallel manipulator.",
+ "texts": [
+ " The noisy input data are obtained either directly from measurements on an experimental prototype or from simulations by adding a Gaussian zero-mean noise to the theoretical joint readouts; the noisy data are then submitted to each of the DPLS and CLS procedures in order to compute their estimates. For simulation, the actual poses of the EE are known from the prescribed trajectory; for experiments, these poses have to be computed from very accurate measurements taken with a coordinate measuring machine (CMM). Shown in Fig. 4 is the experimental prototype, manufactured with rather loose tolerances. Moreover, the joints of the prototype operate under no feedback loop. The EE is held at a specific pose by a stand placed between the two end-plates. A single instrumented leg is used, that is manually placed at each of the six leg locations. Potentiometers are installed on the first three joints. The output voltage of these sensors is sent to a multi-channel 12-bit A/D converter. The resulting digital values are the noisy input data to each of the estimation procedures"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure4-1.png",
+ "caption": "Fig. 4. Axial pro\u00aeles of hob and worm disks.",
+ "texts": [
+ " The position vector OwN of the worm cross pro\u00aele is determined as qw hP qh hM d hM nh hM ; 13 where d hM MN apr hM \u00ff hP 2: 14 Here, nh hM is the unit normal to the hob cross pro\u00aele at M; apr is the parabola coef\u00aecient of parabolic function d hM . It is easy to be veri\u00aeed that tangency of Rh and Rw (of hob and worm thread surfaces) is identi\u00aeed as internal tangency of two helicoids along a common helix that belongs to the cylinder of radius OhP OwP . Worm pro\u00aele crowned surface Rw: Case 2. The hob thread surface Rh is generated by a shaped disk provided with a surface of revolution Rt. Fig. 4(a) shows that the axial pro\u00aele of Rt is a straight line, if Rt is a cone surface. The axial pro\u00aeles of hob and worm disks are in tangency at a chosen point P and deviate each from other at current point M of hob disk pro\u00aele (Fig. 4(a,b)). The deviation d hM MN is determined similarly to deviation represented in Case 1. Hob and worm thread disks are provided with surfaces Rt and Rc, respectively, that generate the hob and worm thread surfaces Rh and Rw as two helicoids being in tangency along a common helix that passes through point P. Worm double-crowning. The above described methods of worm pro\u00aele crowning of the worm yield that worm thread surface Rw and worm-gear tooth surface R2 are in point contact at every instant and the bearing contact is localized"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002810_iros.2005.1545293-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002810_iros.2005.1545293-Figure4-1.png",
+ "caption": "Fig. 4. Limit Distance Model",
+ "texts": [
+ " Both borders are elliptical shaped and have either the speaker or the speaker and listener at their center. 2) Conversation when two or more objects are close to- gether: When two or more objects in the environment are close together, it is difficult for listener to identify the object to only from pointing gesture and a reference term. We define Limit Distance as the distance in which we cannot distinguish the indicated object from the other objects only using pointing gesture and a reference term. The definition of Limit Distance is shown in Fig. 4. The definition shows that listener cannot distinguish the indicated object, if the edge of the other object intrudes into the scope of \u03b8P from the indicated direction. In other words, Limit Distance dLIM is the distance that includes scope \u03b8P and distance S from the object\u2019s center to its edge. The difficulty to distinguish the indicated object from the other objects is dependent on the distance between one object to another object, the distance from objects to the speaker, and the size of the object",
+ " RTM determines which reference term to use by the following rules: \u2022 If dSO \u2264 dLO \u2013 Use \u201cKORE\u201d when dSO \u2264 fKS(dSL, dSO, \u03b8L) \u2013 Use \u201cSORE\u201d when fKS(dSL, dSO, \u03b8L) \u2264 dSO and dSO \u2264 fSA(dSL, dSO, dLO, \u03b8LO, \u03b8L, \u03b8S) \u2013 Use \u201cARE\u201d when dSO \u2265 fSA(dSL, dSO, dLO, \u03b8LO, \u03b8L, \u03b8S) \u2022 If dSO \u2265 dLO \u2013 Use \u201cSORE\u201d when dLO \u2264 fSA(dSL, dSO, dLO, \u03b8LO, \u03b8L, \u03b8S) \u2013 Use \u201cARE\u201d when dLO \u2265 fSA(dSL, dSO, dLO, \u03b8LO, \u03b8L, \u03b8S) LDM estimates whether or not the listener can identify the indicated object with a pointing gesture and a reference term based on Limit Distance. Limit Distance dLIM is given by dLIM = f(S, L, \u03b8P ) = tan\u03b8P (L + cos\u03b8O1\u2212O2) sin\u03b8O1\u2212O2 where the parameters are described in Fig. 4. LDM decides whether the model uses an object\u2019s property by the following rules: \u2022 Use object\u2019s properties, when dLIM \u2264 f(S, L, \u03b8P ) \u2022 Don\u2019t use, when dLIM \u2265 f(S, L, \u03b8P ) OPM chooses an indicated object\u2019s property different from the other objects, which are all in the Limit Distance. OPM has a list of the object properties of each object, and by comparing each property among objects, the model finds the appropriate property. In this research, OPM, however, has only color as an object property. A system to get object properties and an algorithm to compare them are under consideration"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001423_s1350-4533(99)00095-8-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001423_s1350-4533(99)00095-8-Figure4-1.png",
+ "caption": "Fig. 4. The model assumes the path length of the central slip of the EDL changes primarily where it passes over the joint capsules (bold, black arcs). For a given tendon t at a given joint j, the radius of the joint capsule (rt,j), measured from the axis of joint rotation, is assumed constant. Thus, flexion of joint j from 0 to qj rad increases the path length by rt,jqj.",
+ "texts": [
+ " An\u2019s model, based on three-dimensional coordinates estimated from bi-planar photoradiographs, required six parameters per tendon per joint. The present model, based on one-dimensional measurements of tendon excursion, requires only three. The excursion of the EDL requires terms of two types. The first accounts for the central slip of the EDL; the second accounts for the contribution of the lateral bands. The model assumes that the path length of the central slip of the EDL changes primarily where the tendon passes over the joint capsules surrounding the heads of the metacarpal bone and the proximal phalanx (Fig. 4). Anatomical data [12] suggest that a circular arc is a reasonable approximation for the cross-section of the head of the average metacarpal. Thus, the cross-sections of the relatively thin, flexible joint capsules overlying the MCP and PIP are approximated as circular arcs centered on the axes of flexion. Accordingly, changes in path length are assumed proportional to joint flexion (Eq. (5)). Bt,j5rt,jqj (5) where rt,j is for tendon t, effective radius of joint capsule at joint j, and qj is the flexion angle of joint j in radians",
+ " The insertion of lateral bands is treated similarly. Point p \u2192 lat,union gives coordinates of the union of the lateral bands on the terminal extensor slip with respect to coordinate-system-3. Flexion of the distal joint qDIP is assumed to translate this point along the middle phalanx in the direction of x \u2192 3. coordinates of lumbrical origin (p \u2192 LUMo,straight) may be estimated with respect to the metacarpal bone (coordinate-system-0). Flexion of the finger joints {qMCPf, qPIP, qDIP} allows excursion of the tendon as determined previously (Fig. 4). This excursion is assumed to translate the lumbrical origin proximally by (Dp \u2192 LUMo). the EDL (Fig. 7). For simplicity, the kinematics of the extensor hood are initially calculated with respect to the first phalanx, coordinate-system-2. In this frame of reference, it is reasonable to assume the portion of the EDL central slip in contact with the first phalanx does not translate due to flexion or abduction of the MCP joint. When the finger is straight, a point on the extensor hood is given by ( 2p \u2192 hood,straight)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002455_j.precisioneng.2004.03.003-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002455_j.precisioneng.2004.03.003-Figure7-1.png",
+ "caption": "Fig. 7. Location of balls for maximizing and minimizing fc (unit:nm): (a) location of balls for maximizing fc; (b) location of balls for minimizing fc.",
+ "texts": [
+ " The minimum\u2013maximum width, 0.05 m, equals 6\u03c3 (\u03c3, standard deviation) =\u00b1 3\u03c3, in other words \u00b1 0.025 m. The interval of diameter differences is 0.05 m/Z (Z, number of balls). In comparison with Fig. 3, which shows the result in the case that only one ball has a larger diameter by 0.05 m, the expected value decreases. Moreover, the reduction ratio of the fc component also decreases with increasing number of balls. When the fc component is maximized and minimized for Z = 10, the location pattern of balls is shown in Fig. 7. When the fc component is maximized, the larger balls are lined up serially and the smaller balls are lined up at the opposite faces. Furthermore, when the fc component is minimized, a large ball and a small ball are located neighboring each other in order to negate the diameter differences. Balls numbering several hundreds of thousand for rolling bearing are manufactured in a production lot. The required accuracy for each grade and each lot is standardized as in Table 3 [5]. Here, variation of diameter means the maximum (peak) to minimum (valley) value of diameters in one ball",
+ " Tables 4 and 5 show the experimental conditions and the location of balls respectively. The eight balls in type No. 695 bearing are numbered, and the larger diameter ball is symbolized by \u201cL\u201d, and the normal reference diameter ball, \u201cN\u201d in Table 5. The results are shown in Fig. 10. The location of balls has an impact on the fc component although the same number of larger balls are used as shown by the patterns of C and D, E and F and G and H. As a trend, when the larger balls are located serially, the fc component becomes larger similar to that shown in Fig. 7. This experimental result reveals that the location of balls has a significant effect on the fc component value even if the mutual diameter differences of balls are the same in a rolling bearing. This paper focuses on the theoretical analysis for the influence of the mutual diameter differences of balls, which cause the retainer revolution run-out component, fc, as the most important factor in NRRO of rolling bearing. Then, the influence of the location of balls is investigated experimentally. The main conclusions are as follows"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001884_1.1467089-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001884_1.1467089-Figure2-1.png",
+ "caption": "Fig. 2 Analytical model of a tripad slider",
+ "texts": [
+ " In this paper, we investigate the behavior of a tri-pad slider in the near-contact regime using a simple 2-DOF slider model with concentrated air bearing springs and dashpot. In addition, we clarify the effect of the rear to front air bearing stiffness ratio, the friction coefficient and the distance of the head-gap from the rear air bearing center on the spacing variation and the contact or friction force. Figure 1 shows the shape of a typical tri-pad slider with two front air bearing surfaces and one rear air bearing surface. The rear air bearing surface has a contact pad. Figure 1~a! is the bottom view, and Fig. 1~b! is the side view. Figure 2 shows the 2-DOF model of the tri-pad slider and the disk surface waviness which was utilized in this analysis. The tri-pad slider is modeled as a rectangle with length a and height b. The slider suspension system is represented with normal spring stiffness k, angular spring stiffness ku , and damping coefficients c and cu . The air bearing effects are represented by two lumped linear springs ~k f and kr! and dashpot ~c f and cr! which are separated from the center of the mass of the slider by d f and dr , respectively",
+ " Since the disk surface waviness generated by the computer algorithm includes only wavelengths longer than the contact pad length, and wavelengths shorter than the contact pad is regarded as roughness, which is neglected in the calculation, FH and h can be considered to be the height from the averaged envelop line of disk surface roughness. In other words, FH50 in this paper means that FH is equal to the sum of mean value and rms value of the asperity height in actual disks. For example, if the mean value and rms value of asperity height are 2 nm and 1 nm, respectively ~Ra of the disk surface roughness is about 1.4 nm!, FH521.3;2 nm in this paper corresponds to FH51.7;5 nm in actual disks. 3.1 Slider Vibration Modes. Since the slider model shown in Fig. 2 is a 2-DOF system in z-translation and pitch rotation, it has two natural vibration modes which affect dynamic characteristics of the spacing. Furthermore, since the system is changed between non-contact ~flying! and contact states, the lower and higher vibration modes should be considered in each state, in order to understand the following analytical results. Table 2 shows the natural frequency and the node points of the slider vibration modes in each state. f ni and lni are the natural frequencies and the node points, respectively"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002124_3.21202-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002124_3.21202-Figure3-1.png",
+ "caption": "Fig. 3 Phase plane of output q and be.",
+ "texts": [],
+ "surrounding_texts": [
+ "The design procedure can be divided into two steps as follows. A. Sliding Hyperplane Determination While in the sliding mode, i.e., S - 0, a certain linear dependence among the state is as below x2 = ~(GC2r (7a) thus the system in Eq.(4) can be reduced to the following n-m dimensional form (9) there exists a where K = (GC2) 1G. The following lemma is needed. Lemma 712'16: For a matrix C 2 e/? / I x m , matrix G e Rmxp such that K = (GC2)~1G in Eq. (9) can achieve some poles placement if and only if -f] \u00b0\u00b0 , hence it will not affect the equilibrium point of the system Eq. (7b). That is, the sliding hyperplane in Eq. (6) will converge to the following form: so the preceding determination of the matrix G by neglecting <|) is reasonable. Besides, the response prior to this convergence might be not very good. The decay rate of ty can be speeded up by increasing the value of p, however, the control gain will increase too. B. Existence Condition Satisfaction It is well-known that the output can globally reach the sliding hyperplane if1*2 (lla) Because the system is on the sliding hyperplane initially, we only need to consider the existence condition of the sliding hyperplane, i.e., limS (y)S(y)<0 (lib) (7b) and *(0 = x,(t) -(GC2)\"'GC, 0 -(GC2ylGy(0) exp(-pf) (7c) where / e R m x n m is an identity matrix. For convenience, the following notations are used in the sequel of this paper: <8a) (8b)= A12(GC2)-1Gv(0)exp(-pr) and -(GC2)-1GC1 e Rn x (n-m) (8c) The sliding hyperplane S(y) = 0 is determined by choosing the matrix G to stabilize the reduced-order system in the sliding mode. Neglecting the exponential term $ first, Eq. (7b) can be seen as a usual linear output feedback problem To achieve the existence condition in Eq. (lib), the following approach is helpful. Control Selection: For the given system in Eq. (4) with known bound of initial state jc(0), let the control u(y) be selected as (12) where sgn(S) = [sgn.^), ... , sgn(sm)]r, each sgn(^) is a signum function of s/, i = 1,2,. . . , m, defined as sgn(s;) = 1 for st > 0, 0 for Sj = 0, \u2014 1 for Si < 0. Let the constant control gain k E R satisfy the following inequality k > max [ (||GCA||2 + ||GC||2||AA||2) L + PI|Gv(0)||2] (13) where max(-) represents the maximum value of (\u2022) and L is defined as |(GC2)-!Gy(0)|2 (14) for t > 0, then Eq. (lib) holds, i.e., the existence condition is guaranteed. Reason: Substituting Eq. (12) into Eq. (4a) and differentiating Eq. (5b), it yields S = (15) D ow nl oa de d by U ni ve rs ita et s- u nd L an de sb ib lio th ek D us se ld or f on J an ua ry 1 6, 2 01 4 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 12 02 WANG AND FAN: VARIABLE STRUCTURE SYSTEMS 339 It is easy to see, if k > max [ (||GCA||2 + ||GC||2||AA||2) \\\\x(t)\\\\2 + PI|Gy(0)||2] (16) then the existence condition Eq. (lib) can hold. However, x(t) in Eq. (16) is not available, hence Eq. (16) should be modified as follows. Because at the initial instant S[y (0)] = 0, i.e., the initial output is on the sliding hyperplane. From the concept of the equivalent motion, while in the sliding mode, we have the reduced-order system as follows with the aid of Eqs. (8a) and (8b) (17) S(y) = 0 with the initial state *(0). Solving Eq. (17), we get *!\u00ab = exp[A1(r)]jc1(0)+ exp[A1(r-T)]ct)(T)dT (18) For a stable matrix A} and finite vector fy it is clear that both |exp[Ai(f) ]|| 2 and Ij^exptA^-T) ]<|)(T)dT||2 are limited tosome bounded values. The upper bound of the state vector x^t) is I I 2 (19) Further, by Eqs. (7c) and (8c), the upper bound of the state vector x(t) is (GC2) (20) Substituting Eq. (19) into Eq. (20) and according to Eq. (16), Eqs. (13) and (14) are obtained. Remark 2: It is noted that because y (0) lies on the sliding hyperplane 5 = 0 initially, the control u in Eq. (12) with the gain k in Eq. (13) is chosen to force v(r), for t = 0 + Af, 0 < Af <$c 1, remaining on S = 0; moreover, each term of right-hand side of Eq. (13) is taken to be norm value and the maximum value of it is considered. Therefore, we can conclude that Eq. (13) indeed gives a strong enough gain k such that y (f), t > 0, will be kept lying on the sliding hyperplane all the way. Consequently, the control selection is indeed workable. Remark 3: Because the control u in Eq. (12) may give rise to chattering due to the term of signum vector sgn(S), directly applying such a control signal to the plant may be impractical. To obtain a continuous approximation control signal, each element of sgn(S) can be replaced by a smoothing continuous function as17 (21) where each 8,- > 0 is a small positive constant. Because our control design only considers the existence condition of the sliding mode, the output trajectory should be confined to the neighborhood of the sliding hyperplane, so 5, cannot be too large, / = 1, 2 , . . . , m. However, how to choose a set of suitable 8, is still an open problem. IV. Illustrative Example It is difficult to find a practical example with multi-input system. Therefore, for convenience, we adopt the system of aircraft in Ref. 12 to be illustrated. -0.277 1 -0.0002 -17.1 -0.178 -12.2 0 0 -6.67 0 0 6.67 y = 0 1 0 0 0 ij a q A_ (22a) (22b) where a is the attack angle, q is the pitch rate, 8e is the elevator angle, u is the command to the elevator, and y is the measurement D ow nl oa de d by U ni ve rs ita et s- u nd L an de sb ib lio th ek D us se ld or f on J an ua ry 1 6, 2 01 4 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 12 02 340 WANG AND FAN: VARIABLE STRUCTURE SYSTEMS 0 .0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 which is not negative semidefinite. Therefore, the S(y) trajectory with initial state Jt(0) = [ 1 0 1 ]T does not decrease, i.e., the reaching condition Eq. (1 la) fails during a certain period of time (see Fig. 4)."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001061_s0021-9290(00)00032-4-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001061_s0021-9290(00)00032-4-Figure6-1.png",
+ "caption": "Fig. 6. Rotation from attitude (3) to attitude B was divided into two sections by attitude C. The positive 1803 rotation about the long axis (y-axis) of the limb segment from attitude (3) to attitude B can be obtained by the sum of two positive 903 rotations about the same axis from Attitude (3) to attitude C and from attitude C to attitude B. Therefore the gimbal-lock problem is avoided.",
+ "texts": [
+ " If the full cycle was divided into two sections and the axial rotation angle from the \"rst initial attitude n 1 to the second initial attitude n@ 1 is / 1 , and from the second attitude to any attitude in the second section is /@ 1 , then the axial rotation angle from the \"rst initial attitude to any attitude in the second section can be calculated by the additive law as: / 2 \"/ 1 #/@ 1 . (B.1) In the graphic example (Fig. 2), the axial rotation from attitude (3) to attitude B reaches 1803 that is a gimballock point. If an attitude C between the two attitudes was recorded, the problem can be solved by selecting attitude C as the second initial attitude and dividing the full period of time into two sections, attitude (3) to attitude C and attitude C to attitude B (Fig. 6). In the case there may be more than one gimbal-lock point, the number of sections can be determined depending on how many gimbal-lock points involved in an activity, which can be pre-determined according to the activities to be investigated. In order to avoid errors in computing with small angles (Woltring et al., 1985), it is suggested to keep the number of sections to a minimum in case there is no gimbal-lock point in each section. If the rotation in an activity was less than 1803 it is not necessary to divide the whole period into sections"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001771_elan.1140050107-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001771_elan.1140050107-Figure8-1.png",
+ "caption": "FIGURE 8. Dimensionless forward (a) and backward (b) currents of quasi-reversible SW voltammograms; x = 1, y = 0.01 (l), 0.3 (2), and 2 (3). All other parameters are as in Figure 1.",
+ "texts": [
+ " If a SW voltammogram is recorded at a large electrode, when the sphericity is small, inspection of the cathodic and the anodic (i.e., the forward and the back- 36 KomorskyLovriC et al. ward) currents inay offer valuable information on the reversibility of the redox reaction [l]. On very small spherical electrodes, characterized by large sphericity, this information may be lost [5]. The variation of dimensionless foward and backward currents of quasi-reversible SW voltammograms under the influence of dimensionless electrode size ( . y ) are shown in Figure 8. At large values of?), A 4 f loses the maximum, while A+h loses the minimum, and both currents become similar waves separated by 2ESw mV. These principal variations are almost independent of the charge transfer rate. If a redox reaction appears reversible for any y , both currents become waves if y ? 2. The separation between the maximum of A 4 f and minimum of A+b is equal to 20 mV, if y 5 lo-', and increases to 25 mV for y = 0.01, to 35 m V f o r y = O. l , t o6OmVfory=O. j , and to95mVfor y = 1 (all for nAE = -5 mV and nEsw = k 2 5 mV)",
+ " Under these conditions, the SW peak potentials were found to be independent of electrode size if log ( y ) < -2, but depend linearly on log ( y ) , with a slope dEp/d log ( y ) = -2.3 RT/anF, if log ( y ) > 0.5. The simulated SW voltammograms of quasi-reversible reactions were also found to be similar to the corresponding responses found at microhemispherical electrodes. Square-wave voltammograms for oxidation of lo-* M ferrocene in acetonitrile recorded at a 5-pm radius gold inlaid disk microelectrode are shown in Figure 9. Both the forward and the backward components of the SWV response are sigmoidal curves, in agreement with theory (see Figure 8). The SW experiments were performed at four different gold inlaid disk electrodes ( r = 800, 30, 12.5, and 5 pm) and SW frequencies were changed over the range from 10 to 2000 Hz. The heterogeneous charge transfer rate constant for oxidation of ferrocene in acetonitrile has been reported to be equal, or higher than, 6 cm/s [17]. A diffusion coefficient D = 2.3 X cm2 spl was calculated from rotating disk measurements, which is in the range of the literature data [33]. According to the criteria proposed above, a redox reaction appears reversible if x/yo9 > 100"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002091_s0141-6359(99)00027-6-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002091_s0141-6359(99)00027-6-Figure3-1.png",
+ "caption": "Fig. 3. Schematic of the master axis with three capacitance probes.",
+ "texts": [
+ " The experiments are performed on a Bridgeport milling machine equipped with the standard ball-bearing spindle and variable speed drive. As mentioned in the previous section, static or dynamic loads can be applied to the master axis during testing. In the first experiment, a static load is applied in the cross-axis (x)-direction in a rough approximation of an average side milling force. A wire attaches to the master axis stator and carries a static load provided by weights hanging to the side of the machine. The wire cannot carry a moment, resulting in a nearly pure radial load on the master axis. Fig. 3 shows the PMA installed on the vertical milling spindle. In the second experiment, the static load is replaced with a 100 Newton electrodynamic shaker to apply dynamic loads in the x-direction. The PMA shown in Fig. 3 is built from a Professional Instruments BLOCK-HEAD 3R spindle with an integral Data General, 1024 count rotary encoder. The 3R spindle is rated to 15,000 rpm with error motions less than 25 nanometers. The integral rotary encoder provides tachometer and timing pulses used in data collection and spindle error motion calculations. The PMA is held in the milling machine with a collet holding a 2-cm arbor rigidly bolted to the rotor of the master axis. All measurements are made with Lion Precision DMT10 capacitance gauges calibrated to 40 mV/micron"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002386_ip-cta:20030017-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002386_ip-cta:20030017-Figure4-1.png",
+ "caption": "Fig. 4 Regulation based on LFM",
+ "texts": [],
+ "surrounding_texts": [
+ "where and the membership functions RI and R2 are, respectively,\nAssuming that Theorem 3 holds when n = k , then the nonlinear function fx+ I =xIx2...xk+ I can be represented by a weighted linear sum of linear functions of XI in the following form:\n(r:+lnk+l I + 2 rk+lnk+l 2 )),TI\nHence, Theorem 3 holds for all n\nCorollary I [17]: Assume thatx(t) E [Q, Rz]. The nonlinear term\nf ( x ( t ) ) = sin(x(f)) (3 1) can he represented by a linear weighted sum of linear functions of the form\n.fM)) = (i P ; ~ , ( ~ w ) x ( t ) (32)\nwheregl(x(f))= I, g2(x(f))=a and\n11, = rl. r , = , r2=-p2 = r2 sin(.r(f)) - m(f)\n(1 - ' * )X( t )\nx(t) - sinl:~y(t)) (1 - a)z-(t)\nfor x(f) # 0\nr , = I , r2 = 0 for x(t) = 0\na = sin-'(max(R, n,)) Proof It follows directly from Theorem 3. Using Corollary I , an exact T-S fuzzy model of (26) can be represented as follows [17].\nPlant rules:\nRule I : IF xl(f) = RI THEN ~ ( t ) = A,x(t) + B , u ( f )\nand\nRule2: IF x,(t) E THEN ~ ( t ) =A,x(t) + B2a(t) ( 3 3 )\nwhere\n0 1 0 0\n; i :] A z = [ - < - - - I -_ :! B I = ~ = [ ; \\ - 0 -k - 0 - J J aMgl k 0 1 0 0 0 k 0\nJ J J (341\nfor xl(f) # 0 (35)\nr , = I, r2 = 0 for xl(f) = 0\nwhere a = sin-' (max(RI Q,)) and Ti is positive definite for all x l ( f ) E [Q, Q,]. In the simulation, [a, Q2] was chosen as [ -2 .85 2.851.\nAlthough the exact fuzzy model of the flexible joint manipulator does not have any modelling uncertainties since the defizzified output of the T-S fuzzy model is exactly the same as that of the original nonlinear flexible joint manipulator (26), the exact modelling scheme may have some demerit. If the nonlinearities in the system model have very complicated form or the number of them is very large, the methodology presented in Theorem 3 cannot he applied easily.\nAn alternatice T-S fuzzy modelling technique, the linearisation method is often utilised to construct a T-S fuzzy model for a nonlinear system. The linearisation based T-S fuzzy modelling technique is the most popular as it is simple and the consequent rule base becomes intuitive although the modelling error inevitably exists.\nBy applying the Lyapunov linearisation method [17] at operating points xI = - x , 0, x , we obtain the T-S fuzzy model for the robot manipulator as follows:\nR u l e / : I F x l - - x T H E N i = A , x + B I u Rule2: I F r l Z O T H E N i = A 2 x + B Z n Rule 3: IF x, THEN i = A 3 x + B 3 u\nr o 1 0 0 1\nk J\n0 1 0 0\nMgI k 0 - 0 k\n0 0 0 1 k J J\nI\n0 -- k O\nand\n0 Bl = B2 = B, = [ The whole state space formed by the state vector of the original nonlinear equations is partitioned into three different fuzzy subspaces whose centre is located at the centre of the corresponding membership functions shown in Fig. 2.\n4.2 Control results To apply the proposed adaptive fuzzy control scheme, the reference model for the plant state x to follow should be specified. In this simulation, the closed-loop eigenvalues for each subsystem are chosen to he the same, which in\nI\u20ac\u20ac Proc.-Corrml T h m q Appl.. Yol. I50 No. 2. Mcarch 2003",
+ "The PDC controller shares the same fuzzy sets as the fuzzy model to construct its premise part. That is, the PDC controller is of the following form:\n...... reference model 12-\nR': if xi is MF;,\nthen ~ ( t ) = -Ki[.rl xz xi x4]' + L,r(t) (38)\nThe feedback control gains Ki and L; of each fuzzy state feedback controller are updated by adaptive law so that the closed-loop plant follows the reference model (37).\nNow, by using (22), we derive the adaptive law for updating the elements of K j and Lj so that the closedloop plant follows the reference model:\n.\n.'.. ...... LFM based . . .\nwhere B:, = [0 0 0 11\nThe parameters of the nominal plant model used in this simulation are as follows:\nM = 0.2687kg J = 0.03 kgm' L = I m,\nk = 3 1 N / m J = 0 . 0 0 4 k g m 2 and g = 9 . 8 m / s 2\n(40)\nTo test the adaptation abilities of the proposed scheme, the mass oflink is vaned with time as m = 0.2687 + 0.15 sin 3nt and the initial value for state xI is assumed to he xI = n/6.\nThe designed adaptive fuzzy controller was applied to the original nonlinear model of flexible joint maipnlator (26) in the simulation. Figs. 3-5 show the simulation results of regulation of joint angle with exact fuzzy model (EFM) and linearisation based fuzzy model (LFM). From these figures, it is shown that the regulation problem can be solved under parametric uncertainties. Figs. 6-8 show the tracking control results with both EFM and LEM. In both cases, the tracking can be accomplished successfully. The response characteristics of EFM based control such as response time is better than that of LFM based control. This is due to the fuzzy modelling ability of LFM. If more fuzzy rules, that is, linearisation at more operating points can be possible, the difference between the models can be reduced.",
+ "5 Conclusions\nIn this paper, we have developed an altemative T-S fuzzy model based adaptive control scheme via a model reference approach for flexible joint manipulators with parameter uncertainty in their model. We have used an exact fuzzy modelling method and a linearisation based modelling method to represent the flexible joint manipulator. The adaptation law adjusts the contmller parameters on-line so that the plant output tracks the reference model output. The developed adaptive law guarantees the boundedness of all signals in the closed-loop system and ensures that the plant state tracks the state of the reference model asymptotically with time for any bounded reference input signal. The proposed adaptive fuzzy control scheme was ;applied to the tracking control of a single link flexible joint manipulator to verify the validity and effectiveness of the control scheme. From the simulation results, we conclude that the suggested scheme can (effectively\nachieve the trajectory tracking in spite of parameter perturbation.\n6 References\nI KHORASANI, K.: 'Nonlinear fcedback control of flexible joint manipulator: a single link case study', IEEE Truns. Aulom. Conrrol. 1990. 35, ( IO), pp. 1145-1149 2 KHORASANI, K., and SPONG, M.W.: 'lnvafiant manifolds and their application to robot manipulators with flexible joints'. Proc. of IEEE Int. Conf. on Robotics and automation, St. Louis. 1985, pp. 110-1 16 3 KHORASANI, K.. and KOKOTOVIC, P.Y: 'Feedback linearization ofa flexible manipulator near its figid 5 body manifold', Swl. ConIml Lell., 1985,6, pp. 187-192 4 SPONG, M.W.: 'Modeling and control of elastic joint mdnipubdlOrs', ASMEJ Dyn. Swr. Mrur. Cuneoi, 1987, 109, pp. 310-319 5 LOZANO, R., and BROGLIATO, B.: 'Adaptive control of robot manipulators with flexible joints', IEEE Tmns. AuIom. Conool, 1992, 37.\n6 CHEN, K.P., and FU. L.C.: 'Nonlinear adaptive motion control for a manipulator with flexible joints'. Proc. of 1989 IEEE Int. Conf. on Robotics automation, Phoenix. AZ. 1989. pp. 1201-1207 7 TAKAGI, T., and SUGENO, M.: 'Furry identification ofsystcms and its applications to modelling and c u n l ~ d ' , IEEE Tronr. Sy.s~. Mun Cybern.. 1985. IS. (I). pp. l1&132 8 TANAKA, K., and SUGENO. M.: 'Stabiliryanalysis and drsignoffurzy control systems'. Fuzry Seis Sysl.. 1992. 45. (Z), pp. 135-156 9 WANG, H.O., TANAKA, K., and GRIEFIN, M.F.: 'An approach Io fuzzy ccntrol of nonlinear systems: stability and design issues', IEEE Tronr. FtmySy.~f, 1996, 4, ( I ) , pp. 14-23\n10 CHEN, B.S., LEE, C.H., and CHANG, Y.C.: 'H tracking dcsign of uncertain nonlinear SISO systems: adaptive fuzzy approach'. IEEE Tmns. FuzzySy.rt, 1996, 4, ( I ) , pp. 32-43 I 1 SPOONER, J.T., and PASSINO, K.M.: 'Stablc adaptive control u i n g hzy systems and neural networks', IEEE Trans. Fuzzy Svsr., 1996. 4,\n12 WANG, L.X.: 'Stable adaptive furry controllers with application lo invcrted Dendulum trackinr'. IEEE Trans. Fuzzy Swt.. 1996, 26, (5).\npp. 174-181\n(3). pp. 339-359\n- . . pp. 677-691\n13 TSAY, D.L., CHUNG, H.Y., and LEE, C.J.: 'The adaptivc control of nonlinear systems using the Sugeno-type of furry logic', IEEE Foni. Fuzzy $,.TI., 1999, 7, (2). pp. 225-229 14 FISCHLE, K., and SCHRODER, D.: 'An improved stablc adaptive furry control method', IEEE Trans. Furzy Svsr., 1999, 7, ( I ) , pp. 27-40 15 LEU, Y.G., WANG, W.Y., and LEE, T.T.: 'Robust adaptive fuzzy-neural controllers for uncertain nonlinear systems', IEEE TIans. Rohor. Aumm., 1999, IS, (5) . pp. 805-817 16 KAWAMOTO, S.: 'Nonlinear control and \"gorous stabiliry analysis bascd on fuzzy system for inverted pendulum'. Proceedings of IEEE Int. Conf. on F u u y Systcms, New Orleans, Sept. 1996, pp. 1427-1432 17 LEE, H.J., PARK, J.B., and CHEN, G.: 'Robust fuzzy control of nodincar systems with palametric uncertainties', IEEE Tmons. F t r q Svst., 2001, 9, (2), pp. 369-379"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003068_3.20450-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003068_3.20450-Figure1-1.png",
+ "caption": "Fig. 1 Problem geometry.",
+ "texts": [
+ " We shall make the following assumptions: 1) The pursuit-evasion conflict is two-dimensional in the horizontal plane. 2) The speeds of the pursuer (P) and the evader (E) are constant. 3) The trajectories of P and E can be linearized around their collision triangle. 4) P applies a fixed-gain proportional navigation. 5) E has complete information on P's system and on the collision course. 6) Each vehicle's acceleration is subject to a first-order lag. 7) E's lateral acceleration is bounded. (P's lateral acceleration may or may not be bounded.) Referring to Fig. 1, by assumptions 1-3 above we get the following equations: (1) (2) and R = Vp cos(7p0) - Vecos(yeQ) \u00ab V'p - V'e = const Joseph Z. Ben-Asher* and Eugene M. Clifft Virginia Polytechnic Institute and State University, Blacksburg, Virginia PURSUIT-EVASION problems traditionally have been classified among the classical examples of differentialgame theory.1 In recent years a different approach2\"5 has been applied to these problems, namely, to fix the pursuer's Received Dec. 21, 1987; revision received April 17, 1988"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001419_robot.1991.131938-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001419_robot.1991.131938-Figure2-1.png",
+ "caption": "Fig. 2: Basic Parameters of Turning Gaits and Coordinate Systems. (a) Clockwise f i r n i n g Gaits. (b) Counterclockwise Turning Gaits.",
+ "texts": [
+ " of nonlinear equations and inequalities and optimized the variables using the nonlinear programming method. In [lo], Zhang and Song also applied the six foot placing sequences to formulate turning gaits of a quadruped. However, they adopted a different approach, which was a combination of analytical and graphical methods, and developed several simple turning gaits. This paper is an extension of the work in [lo]. Assume that, the quadruped used in this study has four parallelpiped leg workspaces which have overlaps in the longitudinal direction (see Fig. 2) . Depending on the location of the turning center, the turning gaits can be categorized into spinning gaits and circling gaits. The for- 2106 CH2969-4/91/0000/2106$01 .OO 0 1991 IEEE mer are applied when the turning center is a t or close to the body center and the la.tter are suitable for a more distant turning cent,er. In the following, we will first discuss some important definitions and determination of gait stabilit,y margin in turning. We will then study the spinning gaits and optimize the gaits for Stability",
+ " We divide the procedure into three st,eps: 2.1. D e t e r m i n a t i o n of S u p p o r t T r a j e c t o r i e s For simplicity sake, we assume that the turning center is at a fixed point and the vehicle is turning about the center with a constant crab angle cy and a constant speed. Thus, the gravity center is tracing a circle. Hence, the supporting feet are also tracing circles with respect t o the body. I t is also assumed that the support trajectory of a leg passes i ts workspace center C;. Referring to Fig. 2, the chain-dashed circular path is the gravity center trajectory with respect t o the ground. The dashed rectangles are the workspaces of the legs. C, denotes the center of the workspace of leg i and S; and T; respectively denote the starting point and terminating point of a largest possible support trajectory. These positions of S; and T; determine the largest @;\u2019S. When the turning center is outside the workspace of leg i, the foot circular path of leg i has only two intersection points with i ts workspace boundaries, and S; and T; can be easily determined",
+ " If the support trajectory has no intersections with the boundaries a t all, i t is assumed that both S, and T, are coincident with the central point C;. If the support trajectory has more than two intersections with the boundaries, the two points, which are adjacent to the central point C;, should be selected to be the-points Si and T,. 2.2. D e t e r m i n a t i o n of G a i t A n g u l a r S t r o k e 9 Once the coordinates of the points S , and T, have been determined, the polar angles cya, and att of points S , and T, with respect t o the f rame X - 0 - Y (see Fig. 2. ) can be calculated. Thus, the largest leg stroke 9, can be computed as: 9, = 7 ( c y t l - c y s l ) , where 7 = $1 for clockwise turning and 7 = -1 for counterclockwise turning. In case that the angle ut? is smaller (or great,er) than cy,, for clockwise (or counterclockwise) turning, the largest angular stroke Q, should be determined by: Q z = 27r + q(atl - c y s l ) . For a regular and periodic gait, all the legs have the same dut,y factor and leg angular strokes. Hence, the maximum gait angular stroke @ is determined by the minimum of the largest +,\u2019S"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002380_ias.2000.882131-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002380_ias.2000.882131-Figure8-1.png",
+ "caption": "Fig. 8. Current waveform for hysteresis control",
+ "texts": [
+ " High precision in this technique, however, demands a considerable amount of memory. In order to overcome this shortcoming, integration of the flux measurement with an analytical model of the flux or inductance is recommended. It also must be pointed that this technique cannot be applied at very low speed where integration error is significant. Given the fact that mechanical quantities (speed arid rotor position) change much slower than electrical quantities of the machine, one can use stifiess of the system to solve (8) within one chopping as shown in Fig. 8. Neglecting the effects of mutual inductances and assuming that mechanical quantities don't change within a consecutive rise and fall time, (1 1) can be rewritten as follows: I-' ar, 2vj ton +toff L j + j . - -(- ' c% Ai tonto# Although this method has a limited range of speed, has the advantage of simplicity and does not require any additional hardware [9]. VI. SENSORLESS CONTROL AT HIGH SPEEDS In constant power region, where current pulse is significantly shaped and limited by excessive back emf, absence of idle phases will reduce the options for sensorless operation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001500_978-1-4899-1465-1-Figure6.13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001500_978-1-4899-1465-1-Figure6.13-1.png",
+ "caption": "Figure 6.13. Permanent-magnet synchronous motor using surface mounted mag nets.",
+ "texts": [
+ " The figure shows the rotor with the magnet secured in place by slots in the lamination. The slots extending from the mag net cavity toward the periphery of the rotor aid in defining the direct axis magnetic path as a distinctly different magnetic path from the quadrature axis. The torque for the machine is thereby increased be cause of the saliency torque which is proportional to the difference between the reactances in the two axes. In this construction, the mag net is surrounded by die-cast aluminum which fills the rotor slots. A second, commonly used construction is shown in Fig. 6.13. The magnets are secured to the rotor surface and, in this design, there is no no Chapter 6 squirrel cage to provide induction motor-type acceleration. Therefore, the application of this design usually requires an adjustable-frequency power supply. The motor is locked into synchronism at a low frequency and then proceeds to its final operating speed by increasing the fre quency. The absence of the squirrel cage means that the motor must remain operating in synchronism at all times. If the rotor pulls \"out of step\" as a result of an overload or other condition, there is no recovery other than to stop the motor and resynchronize it"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001462_63.712321-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001462_63.712321-Figure6-1.png",
+ "caption": "Fig. 6. Graphical representation of equilibrium points for new DFO scheme at steady state.",
+ "texts": [
+ " Assuming that the system is stable and in steady state, the plant equations (10) and (18) can be replaced by steady-state plant where (29) Combining the plant (29) and the control (16), the necessary condition (30) can be deduced at steady state (30) The above necessary condition at steady state can be rewritten in an angular form (31) using the sum of two complex numbers and (31) with (32) or (33) (34) (35) Confining ourselves now to the case of a machine with positive speed ( ), under positive torque command ( ) and with an observer having a positive resistance error ( ), one can determine the existence of two possible steady-state slip frequencies ( ) which obey (31) through a graphical plot using the loci of and (Fig. 6). These two slip frequencies are given through the vectors and in Fig. 6 after fixing the vector [determined by machine speed and error in resistance and ], the angle (the torque command), and (the angular error in ). The existence of two equilibrium points and confirms the results of the transient analysis with being the stable point because of its lower slip frequency. It corresponds to in the transient analysis. Based on Fig. 6, if the error increases (increase in size of small semicircle) with other parameters ( , , , ) remaining unchanged, the vector increases in magnitude and the two vectors and will approach each other giving the limit condition on the existence of an equilibrium point given in Fig. 7 where . From Fig. 7, we can limit condition (36) The quantity is dependent on and thus also the speed of the machine. The speed that gives the worst situation where is smallest is when . This gives (37) Table I gives the limit condition on the angle for various values of based on (37)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003316_1.1803609-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003316_1.1803609-Figure2-1.png",
+ "caption": "FIG. 2. Lens directions for the Riemannian cubic.",
+ "texts": [
+ " 11, November 2004 Lyle Noakes This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 128.143.199.160 On: Sun, 14 Dec 2014 02:19:27 iVs2dstdi2 = c , s9d where b, cPR are constant. Set d=3siCi2+cd and d\u00b1=3siCi\u00b1\u00cecd2. Example 2: Taking v0, vT as 3 0.0000 0.9280 \u2212 0.3725 \u2212 0.6175 \u2212 0.1225 0.2121 0.7866 \u2212 0.2121 \u2212 0.1225 4, 30.0000 \u2212 0.2708 \u2212 0.2380 0.1155 \u2212 0.0224 \u2212 0.0388 0.3415 0.0388 \u2212 0.0224 4 , the curve of lens directions for the Riemannian cubic shown (thick) in Fig. 2 is less wavy in appearance than the curve for the adapted nonrecursive deCastlejau algorithm of Sec. I. These curves were generated in about 7 seconds on a 2 GHz PC running Mathematica. h There is a special class of Lie quadratics for which quite a lot is known: the Lie quadratic V :S\u2192E3 is called null when its constant C is 0. In Ref. 24 null Lie quadratics in E3 are shown to have constant (usually nonzero) curvature, linearly varying torsion, and two axes. The axes are rays through 0, to which V becomes C0 close as t\u2192 \u00b1`"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003153_146441905x63322-Figure14-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003153_146441905x63322-Figure14-1.png",
+ "caption": "Fig. 14 Positioning of visualization equipment",
+ "texts": [
+ " The communication between computers is established using Ethernet. Some examples of different views inside the virtual harbour are presented in Figs 13(c) and (d). The view from the cockpit mounted on the motion platform can be seen in Figs 13(a) and (b). The physical simulator environment is in a ventilated room. The room is painted with non-reflective colours so that the projected view can be seen more clearly and the outside world fades from sight. The view is projected obliquely forward to the motion platform, as shown in Fig. 14. The projection is done using a mirror attached to the floor and the operator sees the view on a transparent screen. This enables the positioning of the projector so that there will be no shadows caused by the structures of the motion platform. Real-time simulators have several advantages comparedwith traditional operator training. Themachine capacity is not tied to training and can be used in productive work. The use of simulators enables training for situations that can cause severe damage to the operator or environment"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002409_j.ecl.2004.01.001-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002409_j.ecl.2004.01.001-Figure4-1.png",
+ "caption": "Fig. 4. Schematics of the Autosensor and Biographer. (From Garg SK, Potts RO, Ackerman NR, et al. Correlation of fingerstick blood glucose measurement with GlucoWatch Biographer glucose results in young patients with type 1 diabetes. Diabetes Care 1999;22:1708; with permission.)",
+ "texts": [
+ " The Biographer is a small, wristwatch-like device that is worn on the forearm and contains sampling and detection means, electronic circuitry, and a digital display (Fig. 3) [15]. Three separate technologies are incorporated into the GlucoWatch Biographer: glucose sample extraction through reverse iontophoresis, glucose sample measurement by amperometric biosensor, and data verification and conversion using an algorithm leading to the display of the glucose reading [15]. The AutoSensor is a single-use, disposable component that snaps into the Biographer (Fig. 4). It has two identical sets of biosensor and iontophoresis electrodes, and two hydrogel disks. Hydrogel discs serve as the biosensor electrolyte as well as the reservoirs into which the glucose is collected. The glucose oxidase enzyme is dissolved into these hydrogel discs at a concentration sufficient to eliminate enzyme kinetics limitations on the biosensor signal. The Biographer provides 12 hours of glucose readings as often as every 10 minutes with up to six readings per hour. The readings are the timeaveraged measurements of the value 10 minutes earlier and the current value"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003897_009-FigureD.1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003897_009-FigureD.1-1.png",
+ "caption": "Figure D.1. Coordinate system for the region near the three-phase contact line.",
+ "texts": [
+ " Inserting that expression demonstrates that hm \u2248 (\u03b4\u03b6 )2 (\u22121)m 2 \u221a \u03c0 (m + 2) [ \u221e\u2211 k=0 2\u2211 i=0 (m + k + 1 2 ) I\u0302 (i) m (\u03b4\u03b6, k + 1) (\u03b4\u03b6/2)k + o(\u03b4\u22123) ] , (C.14) which are the higher-order corrections to hm given in equation (27). All of the ratios go as A2m+ 3 2 ,k+1 (\u03b4\u03b6 ); by substituting that function into equation (C.14), it can be verified that the sums over k are convergent when \u03b4\u03b6 2. D.1. Potential distribution Here we provide the potential distribution in the singular region near the line of three-phase contact and demonstrate that the energetic contribution of this region can be neglected in cases when droplets are large. Figure D.1 shows a coordinate system suitable to treat the contour along which the three phases meet. The region can be approximated as a wedge geometry, amenable to cylindrical coordinates. Let the axis of the cylinder be along the contact line, R denote a radial coordinate extending from the contact line, and give the azimuthal angle of the cylinder, which ranges from 0 at the electrode in region d to \u03c0 at the electrode in region s. With coordinates constructed in this fashion, \u03b1c retains the same definition"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000674_20.497338-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000674_20.497338-Figure10-1.png",
+ "caption": "Fig. 10. The rotation angle of the \u2018two magnetization vectors within a pole\u201d tedmique for 2D correclions.",
+ "texts": [
+ " In order to solve this problem, we propose a \u201ctwo magnetization vectors within a pole\u201d technique. We define a variable angle which is determined by the shape of the magnetic field distribution near the surface of a magnet This means that the angle is determined by comparing the difference of the magnetic field distribution between experimental data and the calculated values. We modified the magnetization configuration as shown in Fig. 2 by two magnetization vectors within a pole and the angle between these two vectors is defined as shown in Fig. 10. As an example, Fig. 11 shows the torque at a separation distance of 712 2 mm for a 12-12 poles bonded NdFeB magnet device as a function of the angle defined as shown in Fig. 10. The curve shows an increase with angle from -40\u00b0 (at a) to a maximun near 20\u00b0 (at e). The corresponding calculated magnetic field distributions from (a) to (0 as shown in Fig. 11 are presented in Fig. 12. In general, experimental data are close to either (b) or (d) as shown in Fig. 12. Therefore, we can improve the 2D calculation by properly rotating the angle of the two magnetization vectors within a pole of the magnetic gears. In conclusion, 1.he torque of the radial magnetic coupling between magnetic gears with different magnetic poles and different magnetic materials has been studied as a function of the separation &stance by both 2D and 3D computer aided simulation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003283_1.1850940-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003283_1.1850940-Figure1-1.png",
+ "caption": "Fig. 1 Actively lubricated tilting-pad bearing and oil injection system",
+ "texts": [
+ " A mathematical model is derived using two different approaches, aiming at including the effect of oil film active forces. Frequency response functions FRFs of the rotating system operating passively under 2005 by ASME Transactions of the ASME 2016 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded From: http://gasturbine conventional hydrodynamic lubrication and actively under active lubrication are theoretically and experimentally obtained, compared, and discussed. The actively lubricated bearing under investigation is built by four tilting-pads, in a load-on-pad configuration Fig. 1 . The active control forces acting on the rotating shaft are produced by injecting oil into the bearing gap through orifices machined in the pad sliding surfaces Fig. 2 . By coupling two hydraulic servo valves to the pair of pads arranged in the vertical and horizontal directions Fig. 1 , the pressure of the injected oil can be dynamically controlled. Thus, the hydrodynamic pressure, i.e., the main ering for Gas Turbines and Power spower.asmedigitalcollection.asme.org/ on 01/28/2 mechanism of bearing load capacity, can be altered among the different pads, and shaft vibrations can be attenuated aided by properly designing feedback control loops. It is important to emphasize that conventional lubrication is still the main source of load capacity in this hybrid bearing. In addition, the use of active lubrication in tilting-pad journal bearings has the strong advantage of its negligible cross-coupling effects between orthogonal directions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001842_s0043-1648(01)00542-7-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001842_s0043-1648(01)00542-7-Figure2-1.png",
+ "caption": "Fig. 2. Deformation of a semi-infinite body caused by a line load w.",
+ "texts": [
+ " As it was shown in the above example, this assumption leads to an overestimation of the stiffness of the asperities in the elastoplastic regime. On the other hand, it simplifies the numerical formulation of the problem and minimises the time needed for the solution since it allows for better convergence. This is the reason why, even though the assumption of such a material behaviour is somewhat far from the experimental observations, it is adopted by many researchers [25,28,29,32]. In order to study the deformation of a rough surface, a semi-infinite body subjected to line load w along the line x = \u03be will be considered (Fig. 2). The vertical (i.e. along z-axis) deformation z(x) of a point (x, 0) on the surface is given by the well-known Flamant equation [42] z(x) = 2(1 \u2212 \u03bd2)w \u03c0E ( ln \u2223\u2223\u2223\u2223 d\u221e x \u2212 \u03be \u2223\u2223\u2223\u2223 \u2212 1 2 ) (15) where d\u221e is a distance in the semi-infinite body such as d\u221e x. A reference point (xr, 0) is defined on the surface far from x = \u03be , where the line load is applied. It is arbitrarily chosen since it does not affect the pressure distribution and the shape of the deformed surface. The deformation d(x) measured relative to this point is calculated by Eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002799_j.triboint.2005.03.022-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002799_j.triboint.2005.03.022-Figure1-1.png",
+ "caption": "Fig. 1. Hole-entry journa",
+ "texts": [
+ " The effect of surface roughness has been accounted by defining a non-dimensional surface roughness parameter L and a surface pattern parameter g. To account for the flexibility of the bearing, a non-dimensional parameter, called deformation coefficient \u00f0 Dc\u00de has been defined in terms of Young\u2019s modulus of elasticity (E), bearing shell thickness (th), radial clearance (c) and supply pressure (ps). The results presented in this paper are expected to be quite useful to the bearing designers and to the academic community. The geometry of a hole-entry hybrid journal bearing system along with rough surface is shown in Fig. 1. For an elastic bearing, the nominal fluid-film thickness including the bearing shell deformation is expressed as [17,18] h Z 1K XJ cos aK ZJ sin aC w (1) where w is the non-dimensional radial displacement of the fluid-film bearing shell interface. Assuming Gaussian distribution of surface heights, the non-dimensional form of average fluid-film thickness hT is expressed as [23] hT ZEf hC zgZ \u00f0N KN \u00f0 hC z\u00dej\u00f0 z\u00ded z (2) where Ef hC zg is the statistical expectation of local fluidfilm thickness hlZ hC z and j\u00f0 z\u00de is the probability density function of combined roughness z and is expressed as j\u00f0 z\u00deZ 1ffiffiffiffiffiffiffiffiffi 2p s p eK zK2=2 s2 (3) l bearing system",
+ " The bearing shell has been considered to be a threedimensional cylindrical structure of finite length. The deformation field has been discretized using three-dimensional 8-noded hexahedral isoparametric elements. Using three-dimensional linear elasticity equation, virtual work principle and finite element formulation, the system equation governing deformation in an elastic field has been derived [20] as \u00bd K f UgZ Dcf Frg (10) The bearing shell has been assumed to be enclosed in a rigid housing (Fig. 1) and hence, the displacements on the nodes of bush-housing interface is assumed to be zero. f UgZ f0g (11) The solution of the system Eq. (10), after modifications for relevant boundary conditions (Eq. (11)), gives nodal deformations. The bearing static and dynamic performance characteristic parameters are computed using the required expressions presented elsewhere [9,20]. The solution of a compensated hole-entry hybrid journal bearing system considering the combined influence of surface roughness and bearing shell flexibility effects requires an iterative scheme"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002159_6.1993-3761-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002159_6.1993-3761-Figure5-1.png",
+ "caption": "Figure 5, Effect of SCRAMjet Concept on Extemal Forces",
+ "texts": [
+ " So for combustion to occur, the injecton must be accompanied by rapid mixing, the fuel-air ratio must remain in an acceptable range, and the flow conditions in the combustor (e.g., flow ve1ocity)must be maintained. The air flow through the combustor, though su~ersonic. must be held less than the flame v . NC under-~ose NC Ref. Center Under-Afterbody speed, which in turn depends on the mixture ratio. Pressure Olstrlbutlon (e.g. centroid) Pressure Distribution Shown in Fig. 6, from [16,17], is the flame speed and A disadvantage of this concept is that the propulsive system will interact significantly with the aerodynamic control of the vehicle. With reference to Figure 5, from [14], the increased pressure acting on the forebody generates lift and creates a nose-up pitching moment. A counter-acting nose down pitching moment is generated by the external nozzle. Such interactions of the propulsion system with the mixture ratio-relation for hydrogen burning in air. In addition to fuel-flow rate, the engine control effectors may include some form of active inlet device, or some other mechanism for controlling the effective inleddiffuser area ratio AD. In addition, active control of the exit area of the internal nozzle may be required"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002426_s0013-4686(03)00274-3-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002426_s0013-4686(03)00274-3-Figure1-1.png",
+ "caption": "Fig. 1. Schematic view of the optically transparent thin-layer cell. AI, analyte inlet; AO, analyte outlet; CB, printed circuit board; CE, counter electrodes; EF, epoxy resin frame; EH, electrode holder; OS, O-ring sealing; PW, perforation of the working electrode; QW, quartz glass window; RC, reaction chamber; RE, reference electrode; WE, working electrode.",
+ "texts": [
+ " The quartz glass parts are received from Quarzschmelze Ilmenau GmbH, Germany, gold-, platinumand silver-foils from Goodfellow Cambridge Ltd. Furthermore, gold disk electrodes (\u00f8 2 mm, Metrohm) and Ag/AgCl-reference electrodes as well as platinum disk counter electrodes from Kurt-Schwabe-Institut Meinsberg have been used. 4-AP (Fluka, /98%) has been applied as obtained. Tetrabutylammonium hexafluorophosphate (TBAPF6) (Merck, /99.5%) served as supporting electrolyte. All chemicals and solvents were of analytical grade; the solutions were prepared by using double-distilled water. Fig. 1 illustrates schematically the basic design, a characteristic dimension as well as the shape and configuration of the electrode system of a new spectroelectrochemical cell, which has been developed by the Kurt-Schwabe-Institut. The optically transparent working electrode consists of a partially perforated 80 mm thick gold-foil. The lateral length of the square perforations, which were made by laser machining, is 0.4 mm and the strand with 0.1 mm, resulting in an approximate 64% optical transparency of the perforated section of the electrode"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001438_s0094-114x(98)00003-2-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001438_s0094-114x(98)00003-2-Figure7-1.png",
+ "caption": "Fig. 7. The plane of the object movement.",
+ "texts": [
+ " The minimal value of Finternal is determined by the weight of the object and the coe cient of friction at the contact points between the object and the robot end-e ectors and between the object and the environment. So the value of the internal force is determined by the task to be performed. The desired values of the internal force Fd internal, the maximum internal force Fmax,internal, and the minimum internal force Fmin,internal are given by the task planner. An example: two AdeptOne direct drive robots which have the same con\u00aeguration and physical parameters (Fig. 6), perform cooperative work on a single dynamical object, the motion of which is constrained by a dynamical environment (Fig. 7). The robot parameters are given in Table 1. The manipulated object is a polyhedral with a point contact with the constrained environment, with parameters given in Table 2. The environmental constraint is represented by a set of two mutually independent planes, de\u00aened in the Cartesian reference frame Or, Xr, Yr, Zr (Fig. 7): . horizontal plane zea\u00ff0.4 = 0; . vertical plane 2 3 p xea \u00ff 6yea \u00ff 1 0: 57 According to Eq. (57) and Fig. 7, the angle between the XT r -axes of the Cartesian reference frame OT rX T rY T r translated in the plane of the object movement, and the projection of the XT r - axes onto the plane 2 3 p xea \u00ff 6yea \u00ff 1 0 is a = arctg (yea/xea) = 308. The desired object positions in the XT r -direction and in the YT r -direction are de\u00aened by: xd0a t 0:4\u00ff 0:2 exp \u00fft=0:6 0:5 exp \u00fft=0:8 6 6 m yd0a t Fd ey=ky 1=cos a 3 p =3 xd0a \u00ff 0:2 6 6 m : 58 The desired object orientation is jd 0a 30 59 The coordinated robots have to simultaneously realize the following three tasks: . move the object along the desired object trajectory de\u00aened by Eqs. (58) and (59); . exert a nominal contact force Fd ey=20[N] = const. onto the environment in a direction normal to the environment constraint (Fig. 7); . regulate the internal force in the object in the region 0EFx intE500[N], 0EFy intE500[N]. The time duration of the object movement is t = 5[s]. According to Eqs. (35), (36), (42)\u00b1(44) and (47), with the notation used in the previous paragraphs, the model of cooperative manipulation in the example of cooperative work of two AdeptOne direct drive robots which have the same con\u00aeguration and physical parameters (Fig. 6), has the following form: N q q n q; _q;Y0a; _Y0a t 2 R6 1 60 W0a Y0a Y0a w0a q; _q;Y0a; _Y0a Fe 2 R3 1 61 Wca Yca Yca wca q; _q;Y0a; _Y0a Fc 2 R6 1 62 Yca _J q _q J q q 2 R6 1 63 where q qT1 ; qT2 T 2 R6 1 qi qi1; qi2; qi3 T; i 1; 2 Ya YT 0a ",
+ "06 kg m2 Hi qi I1 m*2l 2 1 m*3l 2 1 m*2l1r2 m*3l1l2 cos qi2 \u00ff qi1 0 m*2l1r2 m*3l1l2 cos qi2 \u00ff qi1 Icol: I2 I3 m*2r 2 2 m*3l 2 2 I3 0 I3 I3 264 375; i 1; 2 C q; _q _q G q C1 q1; _q1 _q1 G1 q1 ; C2 q2; _q2 _q2 G2 q2 2 R6 1 Ci qi; _qi _q1 Gi q1 \u00ff m*2l1r2 m*3l1l2 _q2i2 sin qi2 \u00ff qi1 VV1 _qi1 \u00ff VS1 sgn _qi1 m*2l1r2 m*3l1l2 _q2i1 sin qi2 \u00ff qi1 VV2 _q12 VS2 sgn _qi2 VV3 _qi3 VS3 sgn _qi3 264 375 i 1; 2 J q diag fJ1 q1 ; J2 q2 g 2 R6 6 Ji qi \u00ffl1 sin qi1 \u00ffl2 sin i2 0 l1 cos qi1 l2 cos qi2 0 0 1 1 264 375; _Ji qi \u00ffl1 _qi1 cos qi1 \u00ffl2 _qi2 cos qi2 0 \u00ffl1 _qi1 sin qi1 \u00ffl2 _qi2 sin qi2 0 0 0 0 264 375; i 1; 2: The direct kinematics is given by Yia xia yia jia 24 35 l1 cos qi1 l2 cos qi2 Xi base l1 sin qi1 l2 sin qi2 Yi base qi2 qi3 24 35 2 R3 1; i 1; 2; 65 where (X1(base), Y1)base)) = 0, 0), (X2(base), Y2(base)) = (1, 0) are the coordinates of the ith manipulator fundament (Fig. 7). The inverse kinematics is given by q11 arctg y1a x1a arccos x21a y21a l21 \u00ff l22 2l1 x21a y21a q 0B@ 1CA q12 q11 \u00ff arccos x21a y21a l21 l 2 2 2l1l2 q13 j1a \u00ff q12 q21 p\u00ff arctg y2a X2 base \u00ff x2a \u00ff arccos X2 base \u00ff x2a 2 y22a l21 \u00ff l22 2l1 X2 base \u00ff x2a 2 y22a q 0B@ 1CA q22 q21 \u00ff arccos x2a \u00ff X2 base 2 y22a \u00ff l21 \u00ff l22 2l1l2 ! q23 j2a \u00ff q22: 66 The state vector is z YT 0a 6 6 qT T YT 0a 6 6 qT1 6 6 qT2 T x0a y0a j0a q11 q12 q13 q21 q22 q23 T 2 R9 1 According to Eqs. (45), (35) and (36), matrices Wca and W0a are constant diagonal matrices: Wcadiag m1;m1; lz1;m2;m2lz2 diag m 7 ; m 7 ; lz 150 ; m 7 ; m 7 ; lz 150 2 R6 6 67 W0a diag m0;m0; lz0 5 7 m; 5 7 m; 1 2:61 lz 2 R3 3 68 where m and lz are the mass and the moment of inertia of the manipulated object about its mass center, m0 and lz0 are the mass and the moment of inertia of the manipulated object about its mass center after the contacts between the manipulators and the object are established (see Eq",
+ " (62) gets the form: m1 x1a dx 01 _x1a \u00ff dx 01 _x0a \u00ff kx01x0a \u00ff kx01x1a kx01 x00 \u00ff x10 F1x m1 y1a d y 01 _y1a \u00ff d y 01 _y0a \u00ff k y 01y0a k y 01y1a k y 01 y00 \u00ff y10 F1y Iz1 j1a d j 01 _j1a \u00ff d j 01 _j0a k j 01j1a \u00ff k j 01j0a M1z m2 x2a dx 02 _x2a \u00ff dx 01 _x0a \u00ff kx02x0a kx02x2a kx02 x00 \u00ff x20 F2x m2 y2a dy 02 _y2a \u00ff dy 02 _y0a \u00ff ky02y0a ky02y2a ky02 y00 \u00ff y20 F2y Iz2 j2a dj 02 _j2a \u00ff dj 02 _j0a kj02j2a \u00ff kj02j0a M2z: 72 In the above equations kx0i=ky0i=160,000[N/m], kj0i=30[Nm/rad], i = 1, 2 are adopted values of the sti ness coe cients; dx0i=dy0i=1000[N/m/s], dj0i=15[Nm/rad/s], i = 1, 2 are the adopted values of the damping coe cients of the linear and rotational motion. The generalized force Fe at the contact between the manipulated object and the environment may be decomposed in two contact force components: (i) Fey normal to the environmental constraint, and (ii) Fex_Fey (Fig. 7). The contact force component Fea is a sum of inertia, friction and elastic terms: Fey my y*0a hy _y*0a kyy*0a; 73 while the component Fex of the contact forces along the x* 0a>-axis are the sum of inertial and friction terms Fex mx x*0a hx _x*0a nxFey sgn _x*0a ; 74 where, according to Fig. 7, x* 0aO * 0ay * 0a is a new coordinate system, the x* 0a-axis is placed along the path of the movement of the object mass center when the force component Fey=0; the center O* = XT r +x* 0a; my=m0+me, m0 is the mass of the manipulated object, Eq. (1), me is the equivalent mass representing the inertial contribution of the environment, mx=m0, hy, hx, ky, nx denote viscous friction components, environment sti ness and static friction coe cient, respectively. Note that the x* 0a-axis is parallel to the environmental constraint, and taking into account the distance between the object mass center and the contact point d = 0.03 [m], in the OT r , XT r , YT r coordinate system the x* 0a-axis is represented by y0a 3 p =3 x0a\u00ff0.2. The numerical values are: n 0:14;m0 8 kg ;me 1 kg ; dy 500 N=m=s ; dx 10 N=m=s ; ky 50; 000 N=m : According to Fig. 7, the relation between the coordinates x0a, y0a, and x* 0a, y * 0a is given by: y*0a y0a \u00ff 3 p 3 x0a \u00ff 0:2 cos a 75 x*0a x0a \u00ff p* y*0a sin a 1 cos a ; 76 where p* = 0.346[m] is the solution of Eq. (75) when y* 0=y0=0 (Fig. 7). Having the expression for xd0a, and if F0 ey=20[N] = const. and ky are known, the desired object positions are de\u00aened in both coordinate systems: (i) OT rX T rY T r (Eq. (57)), and (ii) x* 0aO*y* 0a (Eqs. (75) and (76)). If the time duration of the object movement is t = 5 s, the length of the desired object path is L xd0a 5 \u00ff xd0a 0 2 yd0a 5 \u00ff yd0a 0 2 0:5 x d0a 0 \u00ff x d0a 5 0:346 m : The paper presents a mathematical model of multiple non-redundant rigid robot manipulators performing cooperative work on a single dynamical object of motion which is constrained by a dynamical environment"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003664_s0263574704000359-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003664_s0263574704000359-Figure2-1.png",
+ "caption": "Fig. 2. Geometric parameters of the HSM.",
+ "texts": [
+ " This paper is organized as follows: Hexa Slide Manipulator (HSM) and its kinematics are described in Section 2. Section 3 discusses the calibration device along with measurement procedure and formulation. Results of computer simulations are presented in section 4. Section 5 concludes the study. This section introduces the parallel robot, HSM, to which the proposed calibration scheme is applied and presents its kinematics. The schematic of the HSM is shown in figure 1 and the geometric parameters are defined in figure 2. It is a 6 DOF fully parallel manipulator of the PRRS type. In figure 2, Aio and Ail denote the start and the end points of the ith (i = 1,2, . . . ,6) rail axis. Ai denotes the center of ith universal joint and it lies on the line segment AioAil. Rail axes are identical and the nominal link length, , is equal for all kinematic chains. The articular variable, \u03bbi , is the distance between the points Aio and Ai. Bi denotes the center of ith spherical joint at the mobile platform. The posture of the mobile platform is presented by the position of the mobile frame center in the base frame and three Euler angles as X = [x y z \u03c8 \u03b8 \u03c6] (1) The Euler angles are defined as: \u03c8 rotation about the global X-axis, \u03b8 rotation about the global Y-axis and \u03c6 rotation about the rotated local z-axis"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002200_elan.1140060107-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002200_elan.1140060107-Figure2-1.png",
+ "caption": "FIGURE 2. CVs of a CuHCF/Nafion (8 prn)/GCE in 0.1 M phosphate buffer at pH 3.5 without (1) and with the addition of 0.5 mM (2) and 2.0 mM (3) cysteine; scan rate, 100 rnV/s.",
+ "texts": [
+ " Lowering the supporting electrolyte pH, on the other hand, resulted in a decrease of peak currents (by jO%, from pH 5.0 to 1.0) and virtually no variation on peak potentials, indicating that the CuHCF film conductivity is more favored in higher pH solutions. All of these observations are clearly responsible for the negative shift of peak potential and for the decrease of peak current on CVs of the CuHCF/Nafion/GCE on changing the supporting electrolyte from 1.0 M KCl to 0.1 M phosphate buffer at pH 3.0 (not shown). Electroca talysis Figure 2 shows the CVs of the CuHCF/Nafion/GCE in 0.1 M phosphate buffer (pH 3.5) without (curve 1) and with the addition of 0.5 mM (curve 2 ) and 2.0 mM (curve 3) Cys. Upon the addition of the analyte, the anodic peak current increased and the cathodic peak current de- creased, the extent of which was proportional to the Cys concentration added. Such a behavior is exactly what wouId be expected for an electrocatalytic CME oxidation. The electrocatalytic capability of the CuHCF/Nafion/GC toward Acy and GSH was also determined"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000561_a:1009888213333-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000561_a:1009888213333-Figure2-1.png",
+ "caption": "Figure 2. Mass on a plane.",
+ "texts": [
+ " The resulting equations of motion are Differential-Algebraic Equations (DAE) that need to be integrated, verifying that constraints are always maintained to avoid integration drift problems. In the next section, a discussion on the modeling issues is presented and the general numerical algorithm is described. An experimental double pendulum is used to validate the simulation. Before presenting the generalized algorithm applied to robot manipulators, the technique is illustrated through two simple examples. The first is the classical problem of a mass sliding on a horizontal plane as shown in Figure 2a. Using a simple static friction model characterized by the kinetic friction fk, the static friction fs , the relative velocity v, and the acceleration a, a friction model that would include stick-slip is given by the following conditional model: if |v| > 0 \u21d2 f = sign(v)fk, v = 0 \u21d2 if { |F | \u2265 fs \u21d2 f = sign(F )fs and a 6= 0, |F | < fs \u21d2 f = F and a = 0. (1) This case is trivial since only one force is applied to the system. In Figure 2b, the mass is on an inclined plane, causing a more complex situation due to gravity affecting the motion. Using the same friction model, the conditions become: if |v| > 0 \u21d2 f = sign(v)fk, (2) v = 0 \u21d2 if { |F \u2212mg sin \u03b8 | \u2265 fs \u21d2 f = sign(F \u2212mg sin \u03b8)fs and a 6= 0, |F \u2212mg sin \u03b8 | < fs \u21d2 f = F \u2212mg sin \u03b8 and a = 0. In both cases, at v 6= 0, friction forces are easily determined from Coulomb\u2019s model and accelerations can be computed. When the mass is at rest, the algorithm checks whether the applied force is high enough to initiate motion or not"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003797_0141-0229(84)90048-6-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003797_0141-0229(84)90048-6-Figure1-1.png",
+ "caption": "Figure 1 Schematic diagram of photomicrobial electrode. A, Polycarbonate membrane; B, immobilized Chlorel la vulgaris; C, Pt cathode; D, Pb anode; E, recorder; F, water bath; G, mirror; H, stirrer; I, reflector lamp",
+ "texts": [
+ " Construct ion o f microbial sensor Immobilization of C vulgaris was performed as follows. Algal suspension ( lml ) containing 1.7x10 s cells was dropped onto a porous polycarbonate membrane (Nucleo- 0141 --0229/84/080355--04 $03.00 \u00a9 1984 Butterworth & Co. (Publishers) Ltd Enzyme Microb. Technol., 1984, vol. 6, August 355 Papers pore filter, Nuclepore Co., Pleasanton, CA, USA, 0.4#m pore size, 2 5 m m diameter, 10/am thickness) with slight suction, and it was fixed on the Teflon membrane of the oxygen electrode. The photomicrobial sensor is shown in Figure 1. The sensor consists of immobilized algae and an oxygen electrode (Ishikawa Seisakujo Co., Model A: diameter 1.7 cm, height 7.2 cm; PVC casing). The sensor was fixed to a 50 ml reaction vessel. Procedure The system for the determination of phosphate was composed of the microbial sensor, a cell, an incubator, a recorder (TOA, Electronics Ltd, Model EPR-200A) and a reflector lamp. The temperature of the cell was maintained at 30 -+ 0.1 \u00b0C, and Tricine buffer (pH 7.6) was employed for the experiments"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003253_j.engfailanal.2004.12.035-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003253_j.engfailanal.2004.12.035-Figure3-1.png",
+ "caption": "Fig. 3. Curing process of the shafts.",
+ "texts": [
+ " Ultimately, this study will become a basis for the enhancement of the capacity of golf shafts and also for the development of their economical manufacturing technologies. Fig. 1 shows the generic patterns of golf shafts which are comprised of a double bias layer followed by the prepreg of a straight layer on the internal mandrel. As shown in Fig. 2, after the completion of laying-up, wrapping is required to maintain the pressure upon the shaft. Polypropylene tape is usually used for wrapping and the line pressure of the shaft is about 30\u201340 kgf/mm. Fig. 3 shows the curing process of the shaft in a hot-air oven. The hardening time in this process depends on the types of resin but the shaft used in this experiment was kept in an oven at 125 C for 90 min. Fig. 4 illustrates the shaft polishing process, which removes its coating and optimizes its delicate surface and size. The characteristics of a golf shaft can be investigated using four different mechanical parameter tests [3]. These four tests are as follows. The frequency of the golf shaft can be defined by its cycles per minute (CPM) when a mass of 205 g iron is hung at its tip, with its butt fixed as shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003358_12.563872-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003358_12.563872-Figure4-1.png",
+ "caption": "Fig. 4. Effective beam width of elliptical beam with triangular dither function",
+ "texts": [],
+ "surrounding_texts": [
+ "An important aspect of the LITI OLED process is the imager, named Alpha. Alpha is a second generation device designed to pattern Gen3 mother glass (550 mm x 650 mm) within an error budget of \u00b12.5 microns over the imaging area. It is based on two 16W Nd:YAG lasers operating in TEM00 mode and focused to a Gaussian spot of 30 microns by 330 microns (at 1/e2 intensity). A block diagram of the optical path is shown in Fig. 2. The system has an optical efficiency of 50% and the power on the film plane can be varied from 0 \u2013 16W. The optical design is based on the premise that transferred line edge quality and precision (e.g. edge roughness variation over the substrate surface) could be improved by increasing the slope of the laser intensity profile in the region of the transfer threshold corresponding to the line edge formation. The method of achieving this goal involves the oscillation of an elliptical beam transverse to the scan direction (figures 3 and 4).22 The oscillation is achieved via acousto-optic beam deflection. Variation of oscillation parameters such as frequency and shape (triangular, sinusoidal, etc.) allow the fluence profile to be tailored to the materials. Figure 5 illustrates the results of a mathematical model of the fluence profile for an undithered beam as well as a beam with three different dither functions. The elliptical beam shape is a factor in achieving the system\u2019s high cross-scan accuracy. However, this comes at the expense of imager in-scan accuracy. The result is that the current imager is configured to write accurate line structures, but not designed to write an arbitrary pattern that requires accuracy in the scan direction (e.g. a delta subpixel configuration). 16 Proc. of SPIE Vol. 5519 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 11/22/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx The optical design allows for continuous variation of several parameters including laser power, effective beam width, beam oscillation frequency, as well as choices for the dither function (e.g. triangular, truncated triangular, sinusoidal, etc.). Therefore, the Alpha imaging platform can expose donor films using a very large parameter space. In practice, these parameters, in conjunction with those of the donor film, are optimized in order to tailor the imaging process to the materials. -100 -50 0 50 100 0.0 0.2 0.4 0.6 0.8 1.0 N or m al iz ed La se rF lu en ce Distance (microns) -150 -100 -50 0 50 100 150 0.0 0.2 0.4 0.6 0.8 1.0 N or m al iz ed La se rF lu en ce Distance (microns) Fig. 5c truncated triangular dither Fig. 5d sinusoidal dither Figures 5a-5c: Representative Fluence Cross Sections"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001393_s0302-4598(98)00186-x-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001393_s0302-4598(98)00186-x-Figure1-1.png",
+ "caption": "Fig. 1. Biosensor assembly.",
+ "texts": [
+ "Sensor U.S. New Orleans USA . The electrode used was \u017dof the gaseous diffusion amperometric type Clark elec.trode . Since the original cap of the commercial electrode used \u017dwas unsuitable for operation in organic solvents which .very quickly corroded it , it was replaced with a similar cap of the same size made of Teflon. Also, the original rubber O-ring used to fix the gas-permeable membrane was replaced with a small Teflon ring. The O determina-2 tion electrode and the modified cap are shown in Fig. 1. The gas-permeable membranes were supplied by Radelkis \u017d .Budapest . The dialysis membrane used was a D-9777 \u017d .type supplied by Sigma St. Louis, MO, USA . The tests were run in a 15 ml thermostatted glass cell provided with \u017da forced circulation water jacket supplied by Marbaglass, .Rome connected to a Julabo model VC 20B thermostat \u017d .Germany . The solvent mixture used in the tests were kept under constant stirring using a magnetic microstirrer from \u017d .Velp Scientifica Italy . The comparative spectrophotometric tests were performed on a Perkin Elmer Lambda 15 \u017d ",
+ "0 ml of the \u017dsolvent to be used respectively, water-saturated chloroform, a 50% by volume mixture of water-saturated chloroform and hexane, water-saturated chloroform containing 1% by volume methanol and a 50% by volume mixture of water-saturated chloroform and hexane containing 1% by volume of methanol, obtaining a solution with a nominal titre of about 3.4 g ly1 in phosphatidylcholine. The titre of phosphatidylcholine standard solutions thus prepared was ( )L. Campanella et al.rBioelectrochemistry and Bioenergetics 47 1998 25\u201338 27 thus monitored spectrophotometrically, using the phospholipid determination kit complete with standard phosphatidylcholine solutions supplied by the manufacturers. \u017d .The proposed biosensor Fig. 1 was obtained by using two enzymes, phospholipase D and choline oxidase, both immobilised in kappa-Carrageenan gel as described in the following section and a gas diffusion amperometric electrode for oxygen as electrochemical transducer. Using this biosensor, on the basis of two enzymatic reactions in series: phospholipaseD lecithin \u2122 cholineqphosphatidic acid choline oxidase cholineq2O qH O \u2122 betaineq2H O2 2 2 2 it is possible to find a correlation between the substrate \u017d .phosphatidylcholine concentration and the oxygen consumed in the enzymatic reaction catalysed by the choline oxidase and, consequently, with the decrease of the current intensity circulating in the measurement apparatus",
+ "0 ml of glycine buffer 0.1 mol ly1, at pH 8.5, and sandwiched between the gas permeable membrane of a gas diffusion amperometric electrode for oxygen and the dialysis membrane. The whole assembly was then fixed to the teflon cap of the electrode with an O-ring, also made of teflon. In the second case, a disk of kappa-Carrageenan gel containing the entrapped enzymes was sandwiched between the gas permeable membrane and the dialysis membrane, and attached to the O electrode as in the preceding2 \u017d .case Fig. 1 . This second procedure, namely immobilisation in kappa-Carrageenan gel, was recently developed by w xour laboratory 17\u201319 . The original procedure involved preparing a 2% prp solution of kappa-Carrageenan obtained by dissolving 0.2 g of the polysaccharide in 10.0 ml of distilled water, and then, after carefully heating, the solution was kept under constant stirring for 15 min. The solution thus obtained was poured on to a Petri dish and allowed to cool, forming a jelly-like disk about 4\u20135 mm thick"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001516_0076-6879(95)46030-6-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001516_0076-6879(95)46030-6-Figure3-1.png",
+ "caption": "FIG. 3. Structure of the long path length OTTLEC thin-layer spectroelectrochemical cell.55",
+ "texts": [
+ " Depending on the length of the hole, the LOPLTTLEC has greater sensitivity than the conventional thin-layer cell. In this cell, the species diffusion is confined within a very thin cylinder. The electrolysis characteristics of the cell are similar to those in other OTTLECs. Zak et al. 54 reported a unique cell containing a glassy carbon or platinum plate with a large area as a WE. The incident light is passed through the solution parallel to the electrode surface. A simpler LOPLTTLEC is shown in Fig. 3. 55 This cell is constructed by inserting the composited one (Fig. 3A) into a colorimetric cell. 55 It can be used in 49 G. Mamantov, V. E. Norvell, and L. N. Klatt, J. Electrochem. Soc. 127, 1768 (1980). 50 S. K. Enger, M. J. Weaver, and R. A. Walton, lnorg. Chim. Acta 129, L1 (1987). 51 j . p. Bullock, D. C. Boyd, and K. R. Mann, Inorg. Chem. 26, 3084 (1987). 52 D. A. Smith, R. C. Elder, and W. R. Heineman, Anal. Chem. 57, 2361 (1985). 53 M. D. Porter and T. Kuwana, Anal. Chem. 56, 529 (1984). 54 j . Zak, M. D. Porter, and T. Kuwana, Anal. Chem. 55, 2219 (1983)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001265_j.fss.2003.07.001-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001265_j.fss.2003.07.001-Figure2-1.png",
+ "caption": "Fig. 2. A single actuated gyroscopic system.",
+ "texts": [
+ " (a) If the output performance is unsatisfactory, then we can decrease the value in Step 4 to cope with the gains of the disturbances and delayed state uncertainties. In addition, when one decreases the parameter su=ciently, then the upper bound on the steady state errors Ne(t) can be made as small as possible. (b) From the above design procedure, the parameters j; j = 1; 2; : : : ; r, in Step 2 are assigned such that (13) is satis9ed. That is, the system designer can tune the size of the residual set by adjusting properly these parameters which are used in (15) or (29). In this section, we consider a gyroscopic system with single actuating input shown in Fig. 2 which is similar to that of [2] but with some slight di5erence in the assumptions made: the gimbals are rigid but is with a little unbalanced bodies and the conservation of the angular momentum constants are not zero. The gyroscope itself can be mounted on a base (aircraft, missile, etc.) that is moving with respect to the earth. Also, the case of the gyroscope can be mounted on a platform so that it can rotate relative to the base. The inertia of the system is concentrated in the rotor, with J as the radial moment of the inertia and I the axial moment of inertia"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure3-1.png",
+ "caption": "Fig. 3. Cross-section of hob and pro\u00aele crowned worm.",
+ "texts": [
+ " Such an approach must be avoided because errors of alignment will cause edge contact on worm-gear tooth surface and transmission errors of unfavorable shape and impermissible magnitude [4,6]. The authors propose application of a worm that is double-crowned (in pro\u00aele and longitudinal directions) with respect to the hob to avoid the shortages mentioned above. Worm pro\u00aele crowned surface Rw: Case 1. The worm pro\u00aele crowning is accomplished by deviation of worm thread surface Rw from hob surface Rh. Fig. 3 shows cross-section pro\u00aeles of the hob and the worm that are in tangency at a certain point P, say the point that belongs to the pitch circle. The deviation of current point N of worm pro\u00aele from current point M of hob pro\u00aele is de\u00aened as MN . The position vector OwN of the worm cross pro\u00aele is determined as qw hP qh hM d hM nh hM ; 13 where d hM MN apr hM \u00ff hP 2: 14 Here, nh hM is the unit normal to the hob cross pro\u00aele at M; apr is the parabola coef\u00aecient of parabolic function d hM . It is easy to be veri\u00aeed that tangency of Rh and Rw (of hob and worm thread surfaces) is identi\u00aeed as internal tangency of two helicoids along a common helix that belongs to the cylinder of radius OhP OwP ",
+ " The worm is double-crowned and its surfaces R i w i I; II) and the unit normals to them can be represented as follows: r i w u i c ; h i c ;wc u i c cos a i c cos cc sin h i c sin wc cos h i c cos wc sin cc sin wc u i c sin a i c \u00ff a i \u00ff ci u i c \u00ff u i co \u00ff 2 h i Eo \u00ff apll2 w \u00ff cos wc u i c cos a i c cos cc sin h i c cos w\u00ff cos h i c sin w sin cc cos wc u i c sin a i c \u00ff a i \u00ff ci u i cw \u00ff u i cwo \u00ff 2 h i \u00ff Eo \u00ff apll2 w \u00ff sin wc u i c cos a i c sin cc sin h i c \u00ff pwwc cos cc u i c sin a i c \u00ff a i \u00ff ci u i c \u00ff u i co \u00ff 2 h i 266666666666664 377777777777775 ; 35 n i c v cw c f u i c ; h i c ;wc 0: 36 Here, (35) are the equations of the family of disk surfaces and (36) is the equation of meshing. The pro\u00aele deviation of the worm is determined by parabolic function dP i ci u i c \u00ff \u00ff u i co 2 i I; II ; 37 where u i c and u i co determine the current and initial locations of pro\u00aele point M i (Fig. 3) and ci is the parabola coe cient. The normals to the worm surface are represented by equation of meshing (36) and equation N i w or i w ou i c or i w oh i c ; 38 that yields N i w u i c ; h i c ;wc u i c cos a i c cos wc cos h i c sin a i c \u00ff 2ci u i c \u00ff u i co \u00ff n sin h i c sin wc cos cc sin a i c \u00ff 2ci u i c \u00ff u i co \u00ff sin wc sin cc cos a i c o u i c cos a i c \u00ff sin wc cos h i c sin a i c \u00ff 2ci u i c \u00ff u i co \u00ff n sin h i c cos wc cos cc sin a i c \u00ff 2ci u i c \u00ff u i co \u00ff cos wc sin cc cos a i c o u i c cos a i c sin h i c sin cc sin a i c \u00ff 2ci u i c \u00ff u i co \u00ff n cos cc cos a i c o 266666666664 377777777775 : 39 Simulation of meshing and contact of misaligned gear drive has been performed for a gear drive with design parameters represented in Table 2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003532_bf00020157-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003532_bf00020157-Figure2-1.png",
+ "caption": "Figure 2. Typical stages of crack growth in compression: (a) unstrained; (b) compressed crack initiation at bound edges; (c) compressed - bulge separates from core; (d) unstrained - showing parabolic crack locus.",
+ "texts": [
+ ") shear modulus (MPa) testpiece thickness (mm) geometrical factor constant displacement subscript loaded area shape fac tor - force free area tearing energy (kJ/m 2) stored strain energy ( J ) strain energy density There is little published reference to the fatigue of rubber in compression. Early investigations by Cadwell, Merrill, Sloman and Yost [1] suggested that failure could occur when rubber blocks were subjected to repeated compression. Hirst [2] has reported that rubber railway buffers, in the form of bonded cylindrical blocks had chunks of rubber removed from the exposed edges similar in form to that depicted in Fig. 2. Lindley and Stevenson [3] have reported a preliminary investigation of fatigue crack growth in non-bonded rubber blocks compressed between rough (high friction) platens. The present paper 47 reports on the extension of this investigation to rubber discs of various sizes and shape factors bonded to metal endpieces. A fracture mechanics analysis is used. determining tearing energy, T (equivalent to strain energy release rate) and crack growth rate. d c / d .~,. The relationship between tearing energy and crack growth rate is compared with that obtained from more conventional fatigue crack growth tests in simple extension",
+ " For conditions of constant deformation, l; where U is the total strain energy stored in the testpiece and A is the area of one surface of the crack. Simple extension. For a uniform rubber strip with a single edge crack of length c, it has been shown [6] that in simple extension (see Fig. 1): r = 2/ wc (31 where W is the strain energy density at strain e, and K is a strain dependent geometrical factor which has been determined experimentally [8] and by finite element analysis [7]. Uniaxial compression. The present analysis refers to solid rubber cylinders bonded to rigid metal discs of the same diameter (see Fig. 2). For such units, the strain energy density W will depend on the shape factor. The shape factor S of a bonded rubber block is defined as the ratio of loaded (i.e. cross sectional) area to the total area of force free surface. For a cylinder of diameter D and thickness h S = D/4h (4) Rubber has a high bulk modulus (2000 MPa) relative to its Young's modulus E ( - 2 MPa) so that most deformations occur with negligible volume change. When a cylinder bonded between rigid end plates is compressed, the rubber bulges to maintain constant volume",
+ " This parabolic shape is consistent with the existence of a parabolic distribution of shear forces in the unit under compression, and has been assumed as a model in the following analysis. Consider a rubber cylinder of radius r, whose centre line is defined by the x-axis in Fig. 3. In this figure, which is a typical cross section, the parabolic crack locus is defined by ABC. The whole testpiece is defined by rotating A C D E about the x-axis. The rubber /meta l bond boundaries lie at x = + d and x = - - d , turned through 90 \u00b0 when compared with Fig. 2. The diameter of the core defined by crack growth is given by 2k. The testpiece thickness is ED, which equals 2d. The equation of the parabolic profile is: y = b x 2 + k , (7) thus r - k d v b = - d 2 and ~ x = 2cx . (8) The length of arc A B C between x = + d and x = - d (twice crack length) is given (b~ integration) as: 2 c = 1 + ( ~ dx d v d 2 2 ( r - / , - ) 2 ( r - k ) / ~ d 'i - 2( r - k ) sinh i d ~- d v d ~ + ~ - r - 7 ~ ~ ( 9 ) Equation (9) indicates that as r - k ~ 0, c -~ d (as expected) and also that as ( r - k ) ~ d, Now for an increase in crack length dc, there will be an increase in crack area dA and a volume of rubber dV from which strain energy is released",
+ " (b) At low compression strains crack initiation will be more likely at the bulge mid-plane and at high strains it will be more likely at the bond edge. (c) As shape factor increases the tendency for radial crack initiation at the bulge will decrease. Crack initiation becomes more likely at the bond at lower applied strains. The predictions (a) (b) and (c) will be compared with actual fatigue test results in Section 6. The compression testpieces consisted of rubber cylinders bonded to metal endpieces of equal diameter (see Fig. 2). The testpiece shape factor S was varied from 0.25 to 5.5 and rubber layer thickness varied from 2 mm to 50 mm. The rubber formulation in parts by weight was natural rubber (SMR CV60) 100 and dicumyl peroxide 1. The compounded rubber was vulcanized in metal moulds for 60 minutes at 160\u00b0C. This formulation gave a translucent rubber which enabled the progress of any cracking into the rubber to be seen with the aid of back illumination. The rubber /metal bonds were formed during vulcanization in the moulds using the bonding system Chemlok 220/205 supplied by Hughson Chemicals, USA",
+ " In one set of experiments with testpieces of shape factor 0,5 compressed to 25% however vertical cracking occurred which grew in a radial direction towards the centre. The inner edge of this type of cracking was observed to be approxi-mately parabolic in shape. These observations concerning the crack Iocii are in agreemeni with the predictions made on the basis of surface strain analysis in Section 4. In each case cracks grew to remove that rubber which at maximum deformation bulged outside the original profile of the cylinder. Thus an inner core was left (see Fig. 2d) beyond which crack growth either did not occur, or at least grew very much more slowly. The shape of the profile of the core was parabolic to a first approximation. It was an interesting feature of crack growth in compression that both the tearing energy, T and the crack growth rate d c / d N were approximately independent of crack length (see Fig. 7 for typical results). This result was the same as that reported previously [3] for fatigue tests with non-bonded rubber cylinders, and is confirmed as a general feature of fatigue crack growth in compression by the present experiments with bonded testpieces"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003550_s0022-460x(86)80032-3-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003550_s0022-460x(86)80032-3-FigureI-1.png",
+ "caption": "Figure I. Non-linear frictional systems with (a) one and (b) two degrees o f freedom.",
+ "texts": [],
+ "surrounding_texts": [
+ "Two examples of systems with friction, of one and two degrees of freedom, respectively, which can'be in chaotic motion for some parameter patterns are shown in Figures l(a) and (b). The equation of motion of the system shown in Figure l(a) is ms (1) If I vo-~l ~< ~ (~ being a very small positive number) and Ikox(t)+ k2x3(t)- Po cos ~tJ < mg/.to, then x(t)= rot. Otherwise, more complicated solutions of equation (1) have to be found. In the work reported here, numerical solutions have been obtained by means of digital simulation. In this work the parameters in the equation were systematically varied, to provide a variety of solutions. Among these were a periodic and an almost periodic solution, as shown by their respective Poincar6 maps; i.e., the point sets on the phase plane (x, ~) with co-ordinates x and :~ such that the time interval between two consecutive 178 0022-460x/86/160178+03 $03.00/0 9 1986 Academic Press Inc. (London) Limited ones is T = 2~r/to. The strange attractor shown in Figure 2 was obtained for the following parameters: m = 1 kg; ko=0; k~ = 1 x 104 Nm-3; a =0-05; fl =0.02; #0=0\"6; Vo = 1 ms-~; Po = 10-5 N; to =23 s-L The initial conditions were x ( 0 ) = 0.001 m are ~(0) =0. Figure 3 shows the amplitudes of the Fourier components versus frequency for x(t) (FFT of chaotic motion). The frequency spectrum for the chaotic motion is continuous, whereas for the almost periodic vibrations it is discrete. By means of analysis of Poincar6 maps an assessment of the influences of the amplitude, the excitation frequency, the coefficients of the friction characteristic, and the non-linear rigidity, k~, on the size and position of the strange attractor, has been performed. The strange attractor was found to be most sensitive to the excitation frequency, among these parameters. The equations of motion of the system with two degrees of freedom shown in Figure l (b) are B(6+(k+k2)(l~ -x)l+c(o+koq~-clmlg sin ~ + kltp 3 = Mosin tot mE+ ( k + k2 ) (x - l~) = mg sgn (Vo-:~)[a + b exp (-d(vo-~))]. (2) 180 LETTERS TO THE EDITOR In this case, particular attention has been paid to the influence of the viscous damping coefficient c on the behaviour of the strange attractor. Figure 4 shows an example of a strange attractor for the following data: ko=0; k ~ = 1 0 0 0 0 N m ; c1=0.12m; B = 0.0073 kgm2; l = 0.1 m; m = 10 kg; ml =0 .5 kg; k + k2=3000 Nm-~; Mo=300 Nm; Vo = 0.2 ms-~; to = 10 s-n; d = 10 sm-n; a = 0.36; b = 0.32 and c = 0.001 Nms. For other values as well (c changing from _0.001 to 5.0). The Poincar6 maps on the plane (~p, ~) are sets of points in a particular-two-dimensional region, while on the plane (x, :~) they are sets of points placed on a straight line. The concentration of the points on the Poincar6 maps becomes greater as the damping value c increases."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003471_1.96982-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003471_1.96982-Figure3-1.png",
+ "caption": "FIG. 3. Photomicrograph of the 3\u00b7 angle-lapped sample after straining. Up per part shows the original surface, where n-type regions are observed as bright stripes. On the angle lapped region below the stripes, bright 0.4 pm depth n-type regions formed within the dark p-type substrate are observed.",
+ "texts": [
+ " This shows that the donor concentration can be changed by adjusting the pulse energy. Furthermore, it was confirmed that laser annealing of the bare silicon surface without sili con nitride film also resulted in donor formation, although a surface ripple occurred. The formation of a p-n junction between unannealed and annealed regions was confirmed by bevel and stain in the following manner. The sample shown in Fig. I was angle lapped (3\u00b0) and immersed in a solution of 200 cc HF and 0.1 cc HN03 under white light illumination conditions. The stained sample is shown in Fig. 3. Bright 0.4 /-lm depth n type regions formed within the dark p-type substrate are ob served. The diode characteristics of the p-n junction were mea sured by making contacts to a 1000 X 60/-lm n-type region and surrounding p-type substrate. The n-type region was fabricated as follows. After forming I-mm-wide aluminum TABLE l. Laser annealing conditions. Wavelength Pulse repetition Pulse width Pulse energy Beam diameter Scanning speed 0.53 pm 4kHz 50 ns 0-1.75 J/cm2 80llm lOmm/s 1205 Appl Phys Lett 48 (18)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003364_0020-7403(88)90076-8-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003364_0020-7403(88)90076-8-Figure1-1.png",
+ "caption": "FIG. 1. (a) Contact configuration; (b) model of contact.",
+ "texts": [],
+ "surrounding_texts": [
+ "technique of [5] to analyse the case of steady-state tractive rolling, which often occurs in practical situations."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.17-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.17-1.png",
+ "caption": "Figure 2.17. Application to bevel gear design.",
+ "texts": [
+ "82) Notice that the first of (2.81) states that the instantaneous speed s of the points of contact are the same, and the second of (2.81) means that their instantaneous rates of change of speed .~ are the same. Of course, as shown by (2.80), the accelerations of the contact points C and D are not equal. 0 Example 2.7. Bevel gears are used to transmit rotary motion between intersecting axles; and their meshed gear teeth assure that this motion will be transmitted without slip. A typical bevel gear arrangement is shown in Fig. 2.17. The bevel angles (} and 1/J are called pitch angles; their sum is the Kinematics of Rigid Body Motion 115 angle between the gear shafts. If the drive gear with a pitch angle 8 has an angular speed wd, determine the angular speed w1 of the driven, follower gear with a pitch angle \u00a2. Assume that the shafts are fixed in the machine. Solution. Because the gears turn about fixed axles and roll on one another without slipping, each pair of points of contact of the gears along their instantaneous contact line AB must have the same velocity. Let r d and r1 be the radii of the mutual rolling contact point A from points on the fixed axles, as shown in Fig. 2.17. Then, in obvious notation, (2.83) Introducing into (2.83) the pitch angle geometry from Fig. 2.17, we obtain the angular speed of the follower gear: w1= wd sin 8/sin \u00a2. (2.84) We see from this result that the angular speeds are independent of the gear sizes, so the same rule holds for both large gears and small gears. Also, (2.84) shows that WI~ wd fore~\u00a2, with Wt= wd when and only when e =\u00a2.In par ticular, when the shafts intersect in a right angle, 8 + \u00a2 = n/2 and (2.84) becomes 0 < 80 in V , p\u030450 on ]V (1) where H L~\u2022 !5 ] ]u S h\u03043 ]\u2022 ]u D1 ] ]z S h\u03043 ]\u2022 ]z D b5 x\u0304 sin u2 y\u0304 cos u22~xG cos u1yG sin u! (2) The film thickness is h\u0304511 x\u0304 cos u1 y\u0304 sin u (3) The bar denotes a nondimensional value and the dot denotes differentiation with respect to time. The geometry and coordinate system are shown in Fig. 1. Rohde and Mallister @5# presented a variational formulation for this class of free boundary problems arising from hydrodynamic lubrication. In these cases, the following variational inequality is written: Let H0 1(V) be Sobolev space and let K5$ p\u0304PH0 1(V); p>0 in V% be the subset of the Sobolev space ~see, for example, Milne @7#!. By introducing the symmetric and elliptic bilinear form on H0 1(V)3H0 1(V): a~\u2022,\u2022 !5E E V h\u03043S ]\u2022 ]u ]\u2022 ]u 1 ]\u2022 ]z ]\u2022 ]z D dudz (4) and the linear functional on dual space of H0 1(V): b~\u2022 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001292_s0014-827x(03)00182-4-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001292_s0014-827x(03)00182-4-Figure2-1.png",
+ "caption": "Fig. 2. Schematic diagram of the flow system used for evaluation of the carbon paste electrode for dipyrone determination. P, peristaltic pump; I, manual injector; S, sample or reference solutions; L, sample volume; C, carrier solution; EFC, electrochemical flow cell; R, amperometer (recorder); W, waste.",
+ "texts": [
+ " This resulting mixture was submitted to magnetic stirring in a beaker (50 ml) containing 20 ml of hexane. The final paste was obtained by the solvent evaporation. The carbon paste was packed into an electrode body (see Fig. 1B), consisting of a polyethylene cylindrical tube (o.d. 7 mm, i.d. 4 mm) equipped with a stainless steel rod serving as an external electric contact. Appropriate packing was achieved by pressing the electrode surface (surface area of 0.126 cm2) against a filter paper. The electrochemical cell was inserted in a one-channel flow injection system schematically represented in Fig. 2. The system was assembled with a peristaltic pump (Ismatec, model 7618-40, Switzerland) and a manual injector made of Perspex\u2020 with two fixed sidebars and a sliding central bar [15]. The manifold connections were made with polyethylene tubing (0.76 mm i.d.). The 0.10 mol l 1 sodium acetate solution was used as the carrier solution (C) at a flow rate of 5.0 ml min 1. The dipyrone reference in 0.10 mol l 1 sodium acetate solution contained in the sample volume loop (l, 408.6 ml) was injected and transported by the carrier stream after the baseline had reached a steady-state value"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002976_0076-6879(86)33084-2-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002976_0076-6879(86)33084-2-Figure3-1.png",
+ "caption": "FIG. 3. Rotating flow mixing device.",
+ "texts": [
+ " 66 However, the mixed solution of TCPO and hydrogen peroxide in ethyl acetate and acetone (1:3, v/v) was found to retain 90% of its original activity after 4 hr storage at room temperature. So, the system shown in Fig. 2 has one pump for the An instantaneous mixing of the two solutions is important for obtaining a stable baseline since the CL reaction occurs instantaneously and the intensity declines very rapidly. For thorough mixing in the flow stream a rotating mixing device has been developed (Fig. 3). The column effluent and the CL reagent solution go into the bottom of the vessel from the opposite sides and are mixed well by rotation. As the mixture rises, it is removed from the top of the vessel. The diameters of the inlets are important to control the flow stream into the vessel of the two solutions to be mixed. A stream flow ratio from 1:4 to 1:10 is preferred for thorough mixing. A delay tube attached to the device is necessary to maintain the appropriate reaction time. Usually 5-40 cm by 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001752_jsvi.1997.1511-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001752_jsvi.1997.1511-Figure2-1.png",
+ "caption": "Figure 2. The conical spring.",
+ "texts": [
+ " Then Ca = L(r'2 + cos2 p) GSA(1+ r'2) , Cb = sin2 pL ESA(1+ r'2) , Cd = L(r2 2 + r1 r2 + r2 1) cos2 p 3GSJ(1+ r'2) , Ce = 4r'2L(r2 2 + r1 r2 + r2 1 ) sin2 p 3ESIN (r'2 + cos2 p) , Cc = L(r2 2 + r1 r2 + r2 1 ) sin2 p cos2 p ESIB (1+ r'2)(r'2 + cos2 p) . (24) 4. STATIC EXPERIMENTAL VERIFICATION Since the diameter of each active coil is different in a conical spring, a larger diameter makes the coils more flexible. The phenomenon of coil close must be considered. The most common type of end turns employed in helical compression springs are ends squared and ground or forged, as shown in Figure 2. Since the pitch angles at two ends are smaller in general, the effect of the end turns can be estimated to achieve accurate determination of coil close in the conical springs. By considering the end effect, where the spring coils are not uniformly spaced at the top and bottom coils, let h(s) be the distance from the bottom edge of the first active coil to the upper edge of the fixed coil. Then h(s)=g s 0 sin p(z) dz\u2212 x(s), 0E sELa , (25) where La is the coil length of the first coil, and x(s) denotes the vertical thickness of the fixed coil"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003496_s10008-004-0524-y-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003496_s10008-004-0524-y-Figure2-1.png",
+ "caption": "Fig. 2 Thin layer setup for NIR-spectroelectrochemical experiments, top: vertical cross section of cell setup, bottom: horizontal cross section of glass assembly, for details see text",
+ "texts": [
+ " The lower edge of this sandwich is immersed into the electrolyte solution; a platinum wire acting as counter electrode and a reference electrode are also placed in the lower vessel. The electrolyte solution is sucked into the gap between the glass sheets by capillary action; generally vacuum has now to be applied at the upper edge. The NIR light passes via fiber optics and suitable collimator lenses through the glass plates. Typical results obtained with this setup are shown below. In the case of spectrometers operating with optical choppers, experiments can be conducted without the need of excluding ambient light. In a more sophisticated setup (see Fig. 2) the glass sheets are mounted in PTFE-rods with slits acting as holders which in turn fit into the bottom of a cell body as shown. The gap between the two glass plates (one plate is coated with ITO and serves as a working electrode) is filled with electrolyte solution upon immersion into the solution pool in the bottom part of the cell. The gap between the glass plates is determined by the thickness of the strips of PTFE-tape inserted at the edges of the plates. Electrical contact is made with a brass clamp at the top edge of the ITO-coated glass sheet",
+ " Frequently the assigned absorptions start in the long wavelength UV-Vis range and extend well into the NIR; consequently this phenomenon appearing as a broad absorption or even only an apparently tilted baseline has been called the \u2018\u2018free carrier tail\u2019\u2019. Optical properties (i. e. absorption) in this range are of particularly practical importance when employing NIR illumination for Raman (especially resonance Raman) spectroscopy [97, 98]. A typical example is shown in Fig. 5. NIR-spectra recorded during electropolymerization of polyaniline on an ITO-glass in a setup similar to the one depicted in Fig. 2 show a sloped line indicative of the free charge carriers being present within the freshly formed polymer. This is in its oxi- dized, i. e. conducting state at ERHE=1 V. The bands can be assigned to the first overtone of the N-H-stretch in an aromatic amine (1500 nm) and to the transition from the valence band into the lower polaron band (binding polaron band) of the benzoid polaron type [99]. The rather featureless absorption between 2400 nm and 3000 nm might be related to mobile charge carriers, its correlation with the electrical conductivity measured in situ is currently under investigation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.9-1.png",
+ "caption": "Figure 2.9. Schematic of the vectors associated with the equation v P = v0 + ro x x.",
+ "texts": [
+ " Unless otherwise stated, use of these units is preferred. On the other hand, in engineering practice the common measure of angular motion often is reported in revolutions and time is in minutes, so in this case the units of ro are written as rpm (revolutions per minute). The con version from one set of units to the other is accomplished by recalling that one revolution is equivalent to 2n rad; thus, 1 rpm = 2n/60 rad/sec. 100 Chapter 2 The vectors introduced in (2.27) are shown in the schematic Fig. 2.9. Additional physical relevance may be assigned to the separate terms in (2.27) by examination of the time derivative in l/1 of the position vector X= B + x of the point P. With the aid of (2.25 ), this yields v p = Vo + x; then it follows from (2.27) that X = v p - v 0 = 0) X X. (2.29) Because x describes the velocity of the point P relative to the base point 0, the quantity ro x x is named the relative rigid body velocity; it is the velocity that the point P would have if the base point were fixed in l/J"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002264_j.ijsolstr.2003.09.054-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002264_j.ijsolstr.2003.09.054-Figure9-1.png",
+ "caption": "Fig. 9. (a) A fixed-ended helical rod; (b) type of dynamic loads.",
+ "texts": [
+ " In the viscoelastic case, the response of the bar dies out with time. The effect of the damping ratio is obvious; increasing the damping ratio causes the response to reach the static response much faster. The dynamic behaviour of the viscoelastic helical bar will eventually disappear and it will approach the static state. The moment Mz is equal to 0 under static loads. However, in the case of dynamic loads, due to inertia forces it assumes values different from 0 (see Figs. 7d and 8d). Example 2. A fixed-ended helical rod shown in Fig. 9 is now considered. The rod has a circular cross-section with the diameter d \u00bc 12 cm. The pitch angle and radius of the helix circle are chosen as a \u00bc 25:52 and a \u00bc 200 cm, respectively. Material properties are: E \u00bc 2:06 1011 N/m2, q \u00bc 7850 kg/m3 and m \u00bc 0:3. Various dynamic loads with the amplitude P0 \u00bc 5 105 N are applied vertically on the arc-length mid-point of the rod. A time increment Dt of 0.02 s is used in the calculations. Non-dimensional vertical displacement at the arc-length mid-point of the rod and non-dimensional shear force, bending moments at the fixed end are shown in Figs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure2-1.png",
+ "caption": "Fig. 2 Scheme of specimens machining for friction measurements",
+ "texts": [
+ " It can therefore be considered as a valid tool for the press-\u00aet curve prediction and the assessment of the in\u00afuence of process parameters. As mentioned above, the friction measurement procedure requires the specimens to be machined directly from the axle and the wheel, thus reproducing exactly the actual surface conditions during the press-\u00aet, in terms of materials, contact geometry, roughness and anisotropy. In particular, the specimens are taken from the zone near the coupling surfaces, as schematized in Fig. 2: a small specimen (called a punch in the following) and a long specimen (called a body in the following) have to be machined from the two components. In the present experiments the punch was obtained from the axle, the body from the wheel. The geometry of the specimens is reported in Fig. 3. The examined materials are carbon steels for both elements, precisely a normalized steel with 0.3 per cent carbon and HV \u02c6 205 for the axle (A1N-UIC 811\u00b11 O) and a quenched and tempered steel with 0.5 per cent carbon and HV \u02c6 260 for the wheel (R7T-UIC 812\u00b13 O)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000482_39.666569-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000482_39.666569-Figure1-1.png",
+ "caption": "Figure 1. PF optimization principle illustration",
+ "texts": [
+ " The optimal controller scheme proposed here is implemented on a conventional structure of a Field Oriented Control (FOC) of an induction motor. It leads to setting the Power Factor (PF) to its rated value, according to a simple equation, by adjusting the magnetization current component with respect to the torque current component. The main advantage of the proposed method is its simplicity. In fact, it does not require an apriori knowledge of the induction motor model parameters. Optimization Principle: The optimization principle can be explained by considering Figure 1, describing the induction motor operation by a circle diagram. Here, the optimal PF (approximately rated one) is reached when the stator current vector becomes tangent to the circle. Therefore, several optimal points can be determined. For example, the optimal point P, corresponding to the circle CA and the magnetization current IN; and also the optimal point B, corresponding to the circle CB and the magnetization current Zfl. As illustrated by Fig. 1, the IEEE Power Engineering Review, May 1998 63 point A has a low PF. It is possible to improve this PF, maintaining the same active power, by moving the pointA to B location (optimal PF). In this case, the magnetization current is reduced (I@ < I@). The stator current is then reduced leading to copper losses decrease (i2t). Moreover, magnetization current decrease leads also to iron loss decrease. Finally, loss balance can be obtained approximately leading then to a maximum efficiency. Optimization Algorithm: According to Figure 2, the PF is expressed in the d-q frame by In the da-qa frame, it becomes The following relationship is then deduced"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003008_1.1757488-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003008_1.1757488-Figure3-1.png",
+ "caption": "Fig. 3 Prismatic dislocation loop in a plate. Distributions of virtual loop defects are shown on the plate surfaces.",
+ "texts": [
+ " The energy of the inclusion in a half-space is E5 8pG\u00ab*2~11n!Rsph 3 3~12n! 2 4pG\u00ab*2~11n!2Rsph 3 9~12n! \u2022 1 h\u03033 , Rsph 0, is called the plane of principal curvature. 30 Chapter 1 Now let us construct in this plane lines through P and A perpendicular to C. The point B where these lines intersect is named the center of curvature. The circle of radius BP with its center at B is identified as the circle of curvature. This circle assumes the shape of the curve along a small arc that includes the point P. We are going to show that this radius is equal to R; hence, R will be called the radius of curvature. To see this, let L be a line through P fixed in the plane of principal cur vature and making an angle 8 with the tangent at P. We see in Fig. 1.12 that the infinitesimal angle between the tangents at P and A is A8, so As= RA8 and IAtl = ltl L18. These approximations become more precise as Lfs is made smaller. In the limit as As--+ 0, we obtain I d81 =_!_ ds R' l:l=ltl=l. (1.67) We now recall ( 1.65b) and use the chain rule to write K= ldt/dsl = !dtjd8!!d8/ds!. Then substitution of (1.67) yields the important result K= 1:1 = ~~~~ =~. ( 1.68) Thus, as remarked earlier, the curvature K measures the rate of change in the tangent angle 8 with respect to arc length along C; and it is clear that [R] = [K~ 1 ] = [L]",
+ "71) that in every rectilinear motion in the direction t v = St and a = st. ( 1.73) We recall that a uniform motion is a special rectilinear motion with constant speed; thus, v = st = v0 , a constant, and a= 0, as described before. (ii) Circular Motion. It is clear that in a motion on a circle of radius r the tangent vector is tangent to the circle. The principal normal vector at every point around the circle is directed through the center of the circle, so this point is the natural center of curvature of the circle described earlier in Fig. 1.12. Thus, the radius of curvature of a circle is the radius of the circle: R= 1/K=r. Notice that the same result follows from the last of ( 1. 72) and the elemen tary formula s = re for a circle on which e is the angular placement of an arbitrary radial line from a fixed line through the center. Therefore, we have s = rO and s = rli. Substituting these relations into ( 1.70) and ( 1. 71 ), we obtain the special elementary equations for the motion of a particle on a circle of radius r with angular speed w = 0 and angular acceleration dJ = lJ: v= rwt, ( 1"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002670_elan.200403190-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002670_elan.200403190-Figure7-1.png",
+ "caption": "Fig. 7. SECM characterization of BDD electrodes: SECM image of BDD surface (50 50 mm) reactivity in an aqueous solution containing 10 mM K3Fe(CN)6 and 0.5 M Na2SO4 at constant height (L\u00bc d/a\u00bc 1.3) and at scan speed of 1 mm s 1 (Etip\u00bc 0.1 V vs. Ag/ AgCl, EBDD\u00bc 1.1 V vs. Ag/AgCl), A) prior to 2\u2019-deoxyadenosine oxidation and B) after 2\u2019-deoxyadenosine oxidation (polarization 900 s at 1.55 V (vs. Ag/AgCl) in a 0.5 M Na2SO4 solution containing 2.5 mM of 2\u2019-deoxyadenosine). C) Approach curves in an aqueous solution containing 10 mM K3Fe(CN)6, 0.5 M Na2SO4 and after polarization 900 s in 2\u2019-deoxyadenosine at different concentrations at 1.55 V (vs. Ag/AgCl). Scan rate\u00bc 1 mm s 1, Etip\u00bc 0.4 (vs. Ag/AgCl), EBDD\u00bc 1.05 V (vs. Ag/AgCl).",
+ "texts": [
+ " Three processes, that cannot be fully discriminated by impedance measurements, can be thought of: i) formation of a porous film enabling diffusion of nucleosides within pores or pinholes, ii) formation of a compact film capable of electron transfer and iii) blocking process due to the adsorption of reactant on electroactive sites. To discriminate these three mechanisms, we performed three sets of experiments. Redox mediators were used to probe the BDD modified surface either macroscopically by DPV (Fig. 6C) and CV (results not shown here) or locally by SECM (Fig. 7). DPV experiments were performed using ferrocene methanol as redox indicator to visualize the evolution of the fouling process without possible interactions between 2\u2019-deoxyguanosine and the modified BDD surface and at less anodic potentials to obtain favorable signal to background ratios. Figure 6C shows clearly the decrease of the redox indicator s response with the increasing polarization time. The decrease in the DPV current response of 2\u2019-deoxyguanosine (Fig. 6A, *) and ferocene methanol (Fig. 6A, ~) are thus indication that the same electron transfer is followed by both species. This validates furthermore the use of redox indicators to characterize the adsorption phenomena. We are currently analysing more deeply this adsorption behavior by modelling the voltamperometric responses of these redox indicators. Otherwise, oxidized BDD surface reactivity was probed prior and following polarization in 2\u2019-deoxyadenosine by SECM (Fig. 7). The SECM tip was used in the positive feedback mode using hexacyanoferrate(III) as redox mediator. Figure 7 displays the SECM image of the local BDD electroactivity, scanned over a 50 50 mm2 surface at constant height, before (Fig. 7A) and after polarization (Fig. 7B) in adenosine solution (2.9 mM, 900 s at 1.55 V vs. Ag/AgCl). Prior to oxidation of 2\u2019-deoxyadenosine, the surface 2D-image shows an inhomogeneous surface reactivity, which may be related to BDD surface heterogeneities. After polarization in adenosine, the recorded feedback current was lowered by an average factor of 15% and the resulting SECM image shows \u201chomogenization\u201d of the surface reactivity. Bard and co-workers [44] have already described such a comportment with SAMs modified gold Electroanalysis 2005, 17, No",
+ " In this case, the electroactive surface is partially covered by an alkanethiol layer that could present punctual defects such as pinholes. Individual defects could be detected only if they are well separated and not smaller than 0.1 a, where a is the electrode diameter. If these defects are closely spaced and smaller than the aforementioned critical size, the probed surface will appear partially conductive, thus presenting an average reactivity, which is dependent on the size and the distribution of the defects. The SECM image of our surface appears homogenous as seen in Figure 7B. Moreover, this homogenous decrease in surface reactivity depends clearly on the polarization duration and on the nucleoside concentration. The latter effect as well as the impact of polarization is visibly looking Electroanalysis 2005, 17, No. 5 \u2013 6 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim at the different approach curves to the different surfaces (Fig. 7C). Prior to polarization, the approach curve of the oxidized BDD surface follows the classical shape of the positive feedback mode corresponding to fast mediator regeneration at the BDD interface. Following 900 s polarization of the interface at 1.55 V (vs. SCE) in increasing concentrations of 2\u2019-deoxyadenosine (from 0.2 to 1 mM), the approach curves move away from the pure positive feedback mode and tend to a negative feedback comportment. This behavior is likely to be related to a loss of surface reactivity of the BDD substrate. In the work [44], Bard et al. have developed a model that mimics finite heterogenous kinetic with SAMs modified gold electrodes. This model depends on two parameters: the diffusion coefficient of the redox mediator which is fixed by the choice of the latter and the apparent heterogeneous rate constant keff which represents the sole adjustable parameter. We used this model to fit our approach curves to the BDD modified surface (black lines in Figure 7C correspond to the theoretical positive and negative feedback). In the case of the oxidized BBD surface prior to adsorption, a heterogeneous rate transfer of 0.3 cm s 1 is obtained using Bard s model. However, it is important to note that the estimated heterogeneous transfer rate of ferricyanide is a few orders of magnitude higher than reported using classical electrochemical characterization techniques for oxidized BDD films [1]. The model has thus to be refined for our application. Nevertheless, the modelling of the approach curves following polarization in increasing concentrations of 2\u2019-deoxyadenosine shows a dramatic decrease of this heterogeneous transfer rate with the nucleoside concentration. For example, keff falls to an estimated value of 0.001 cm s 1 for 2\u2019-deoxyadenosine concentration of 1 mM. This variation of keff can be correlated to the surface coverage of the substrate by insulating species. The estimated surface coverage for polarization in the higher 2\u2019-deoxyadenosine concentration (c\u00bc 1 mM) is about 99%. This result is in accordance with quasi-insulating behavior of BDD substrates (Figure 7C) after 900 s polarization in 1 mM adenosine solution. The SECM images and approach curves thus reinforce previous experimental evidences obtained by DPV (Fig. 6C). However, at this stage, SECM does not allow us to discriminate between the three hypothesis proposed to describe adsorption (e.g., blocking electrode, porous film or continuous film). The modelling cyclic voltammetry data are under way to shed more light into this complex process. Boron doped diamond thin films obtained by plasma enhanced CVD were applied to bioanalysis owing to their intrinsic properties: their carbon nature and their enlarged electrochemical window in aqueous media"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002546_jpsj.73.1082-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002546_jpsj.73.1082-Figure5-1.png",
+ "caption": "Fig. 5. Schematic explanation for the investigation of the influence of the consolidation terrace just behind the growth front in migration phase upon the colony expansion.",
+ "texts": [
+ " This means that the cell density has to increase to a certain value for the beginnning of a colony growth and that the threshold density value for the migration phase exists. (iv) From the result (iii), the periodicity in the bacterial motility is considered to reflect physical properties as the group of bacterial cells. Then we can focus our attention on the dependence of the local cell density on their motility. In practice, we sector a part of the outermost ring of a colony together with an agar plate during the migration phase of the colony growth, as shown in Fig. 5. And we investigate the variation of ring formation for removing the influence from the inner concentric rings. As the result of the experiment by P. mirabilis, it has been found that migration phase and consolidation phase of the separated part of the ring are shorter and longer, respectively, than the rest part. It has also been found that the cell density of the separated part in the first migration decreases and that the width of the ring becomes smaller. These results tell us that the end of migration phase depends on the local cell density and suggest the existence of another, lower threshold density for stopping the colony expansion by active bacteria"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001061_s0021-9290(00)00032-4-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001061_s0021-9290(00)00032-4-Figure5-1.png",
+ "caption": "Fig. 5. The rotation of a body-\"xed unit vector about an arbitrary axis (O@OA) in a three-dimensional reference frame (XYZ). n is the unit vector of the rotation axis O@OA, n 1 and n 2 are the body-\"xed vectors before and after the rotation, h is the rotation angle. The body-\"xed unit vector has been transformed onto the rotation axis for the analytical purpose.",
+ "texts": [
+ " Therefore, it is hoped that this method can be easily understood and accepted by clinicians to bridge the communication gap between clinical descriptions and mathematical presentations of limb segment or joint rotations. This method has been successfully used in the kinematic analysis of three upper limb activities; lifting weights, simulated vehicle steering and door opening/closing (Cheng, 1996). It is believed that the method can be used not only in the biomechanics of human movement for describing the 3D rotation of limb segments, but also in other \"elds for describing the 3D rotation of any moving object. Appendix A. Derivation of Eq. (4) In Fig. 5 XYZ is a reference Cartesian coordinate system with base vector e\"[i j k]T. O@OA is the axis of rotation and n is its unit vector. AB and AC represent the positions of a body-\"xed unit vector n 1 and n 2 before and after rotation, respectively. DB is perpendicular to AD, E is the mid-point of BC and DE is perpendicular to BC. A is the starting point of the body-\"xed vector on the axis of rotation. h is the rotation angle. The purpose of the following analysis is to \"nd n 2 from the known n, n 1 and rotation angle h. First some geomet- rical relations in Fig. 5 can be obtained by vector operations as: BC\"n 2 !n 1 , (A.1) AE\"(n 2 #n 1 )/2, (A.2) DBCD\"2D EDtan (h/2). (A.3) Because BC is perpendicular to both n and DE, it can be expressed as: BC\"a 1 n]DE, (A.4) where a 1 is a constant to be determined. The magnitude of vector BC is DBCD\"a 1 DnDD EDsin (p/2)\"a 1 D ED (A.5) because n is a unit vector. From Eqs. (A.3) and (A.5), a 1 can be found as: a 1 \"2 tan (h/2). (A.6) Thus BC\"2 tan (h/2)n]DE \"2 tan (h/2)n](AE!AD) \"2 tan (h/2)n]AE (A.7) because n and AD are parallel"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003758_acc.1986.4789043-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003758_acc.1986.4789043-Figure1-1.png",
+ "caption": "Figure 1: Block Diagram of Computed-Torque Control Scheme",
+ "texts": [
+ " In order to evaluate the effect of approximating the position dependent inertia matrix D(@) by a constant diagonal inertia matrix J we have also implemented the reduced feedforwward compensation scheme. In the sequel, K and K, are the constant and diagonal position and vefocity feedback gain matrices, repectively; 0 and Od are the measured and the reference joint position vectors, repectively; and the symbol denotes the derivative with respect to time. Computed-Torguee Control Scheme (CT) This scheme, depicted in Figure 1, utilizes nonlinear feedback to decouple the manipulator. The control torque T is computed by the inverse dynamics equation in (1), using the commanded acceleration instead of the measured acceleration 0, as: 790 Authorized licensed use limited to: University of Edinburgh. Downloaded on June 14,2020 at 21:17:37 UTC from IEEE Xplore. Restrictions apply. =r fl)(0)1K (O-) + K (%-O) + &,J (2) + ff(oJ,) + j(O) where the \" indicates that the estimated values of the dynamics parameters are used in the computation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002264_j.ijsolstr.2003.09.054-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002264_j.ijsolstr.2003.09.054-Figure1-1.png",
+ "caption": "Fig. 1. The rod geometry.",
+ "texts": [
+ " Ordinary differential equations with variable coefficients can also be solved exactly in Laplace domain by using the complementary functions method. In the solution of viscoelastic helical rods, the Boltzmann\u2013Volterra theory is considered. Numerical results for elastic\u2013static, quasi-static, elastic\u2013dynamic and viscoelastic dynamic responses of helical rods are presented. Consider a naturally curved and twisted spatial slender rod. The trajectory of geometric center G of the rod is defined as the rod axis and its position vector at t \u00bc 0 is given by r0 \u00bc r0\u00f0s; 0\u00de where s is measured from an arbitrary reference point s \u00bc 0 on the axis (Fig. 1a). Let, at any time t, a moving reference frame be defined by unit vectors t, n, b with the origin of the axis of the rod is chosen such that t \u00bc or0\u00f0s; t\u00de os \u00f01\u00de where t, n and b are unit tangent, normal and binormal vectors respectively. The following differential relations among the unit vectors t, n, b can be obtained with the aid of the Frenet formulas (see Sokolnikoff and Redheffer, 1958) ot=os \u00bc vn; on=os \u00bc sb vt; ob=os \u00bc sn \u00f02\u00de where v and s are the curvature and the natural twist of the axis, respectively",
+ " It is noted that v is always positive and that s is positive for a clockwise rotation about t when advanced in the increasing s-direction. They are expressed in terms of the spatial derivatives of the position vector r0\u00f0s; t\u00de: v \u00bc o2r0 os2 ; s \u00bc or0 os o 2r0 os2 o3r0 os3 v2 \u00f03\u00de For planar rods s \u00bc 0, and for straight rods v \u00bc s \u00bc 0. A second rectangular frame \u00f0x1; x2; x3\u00de is introduced such that the x1-axis is in the direction of t, and x2, x3 axes are the principal axes of the cross-section (Fig. 1b). Let i1, i2 and i3 be the unit vectors along x1, x2, x3. From Fig. 1b Eq. (4) can be written. t \u00bc i1; n \u00bc i2 cos h i3 sin h; b \u00bc i2 sin h\u00fe i3 cos h \u00f04\u00de Let the displacement of a point on the rod axis, and the rotation of the cross-section about an axis passing through G be denoted by U0\u00f0s; t\u00de and X0\u00f0s; t\u00de, respectively. Also, let c0\u00f0s; t\u00de and x0\u00f0s; t\u00de, stand for extension and rotation of the unit length on the rod axis, respectively. On the other hand, let T\u00f0s; t\u00de and M\u00f0s; t\u00de denote, respectively, the resultant of the internal stresses acting on the cross-section, and the resultant moment obtained when T\u00f0s; t\u00de is carried to the geometric center G"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002931_te.2004.825528-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002931_te.2004.825528-Figure7-1.png",
+ "caption": "Fig. 7. Servomotor shaft position and corresponding required pulsewidths.",
+ "texts": [
+ " The R/C servomotor, equipped with a position feedback control circuit and a decelerating gearbox assembly, provides a simple control mechanism. (The internal construction of the decelerating gearbox assembly and the feedback potentiometer of servomotor are given in [13].) The R/C servomotor is controlled by a PWM signal, which can drive the motor to a desired position according to the width of the pulse. In this design, the Mitsubishi M51660L control chip is adopted as an R/C servomotor controller. (For the details of the driver circuit, refer to [14].) Fig. 7 shows the shaft positions of the servomotor and the corresponding required pulsewidths. Given a 0.5\u20132.5-ms pulsewidth, the R/C servomotor can rotate from 90 to 90 clockwise. The output shaft of the servomotor can drive the linkage so that the movable part of the prosthesis rotates with respect to the swivel and then closes the palm of the prosthesis. The output torque of the servomotor is approximately 3 kg-cm so that the designed prosthesis can easily grasp an object that weighs 1 kg. The students can use a microcontroller to easily generate an appropriate pulsewidth"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001059_12.403696-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001059_12.403696-Figure4-1.png",
+ "caption": "Figure 4. Bending line and deflection curve characterized by (xB, zB, \u03c6B) of a flexure hinge",
+ "texts": [
+ " In figure 3 the displacements of point B of a flexure hinge and of an ideal rotational joint are represented. The resulting deviations are \u2206r = 80 \u00b5m at an angle of \u03c6B = 20\u00b0. To derive a kinematic description of flexure hinges the deflection curve of a point lying on hinge link 2 (l2) has to be determined. The hinge is cantilevered at x = 0 and forces or moments are exerted in point B. The displacement curve of point B is characterized by the coordinates xB, zB and \u03c6B at different loads. Assuming link 2 to be rigid, the angles \u03c6C and \u03c6B are identical and \u03c6B corresponds to the hinge angle (fig. 4). For the determination of the coordinates of point B the deflection curve bending line of the hinge must be calculated. Assuming the geometrical moment of inertia to be a function of the beam length s, the bending line of a cantilever beam can be computed as well.8 Proc. SPIE Vol. 4194160 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/17/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx With the assumption that the material is linear elastic, the undeflected beam axis is straight, the plane of symmetry is identical with the loading plane are, the cross sections remain even and the beam length is large to the cross-sectional dimensions, the following well-known beam moment-curvature differential equation system can be deduced: (s- beam length of curve, x- coordinate along the undeflected beam axis, z- transverse deflection, \u03c6- angular deflection of the beam axis with the x-axis, M- moment, E- Young-Modulus, I- geometrical moment of inertia, d\u03c6/ds=1/R- curvature) )( )( sEI sM ds d M = \u03c6 (2) \u03c6cos= ds dx (3) \u03c6sin= ds dz (4) Loading a flexure hinge it must be assumed that the beam length is not long in comparison to the cross sectional dimensions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001559_physreve.62.5056-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001559_physreve.62.5056-Figure6-1.png",
+ "caption": "FIG. 6. Schematic representation of molecular configuration. u\u0302 and v\u0302 are unit vectors, L is the distance from the point of intersection to the center of the rod, and g is the bend angle of the V-shaped mesogen. Dotted mesogen illustrates a host mesogen in the mesogen in a position, the interactions of which are overcounted by the independent rod approximation.",
+ "texts": [
+ " Specifically the phenyl-oxygen \u2018\u2018single\u2019\u2019 bond can have highly bent conformers. However a detailed analysis, presented elsewhere @8#, suggests that this is not the case. Thus, given the crudeness of most models for liquid crystalline elastic constants, we feel that it is reasonable to model our dopant as two rigid segments of a molecule attached to each other through a bend of g5120\u00b0. We shall describe the orientation of such a molecule by using the two orthogonal unit vectors u\u0302 and v\u0302 , shown in Fig. 6. The effective interactions of this molecule with the liquid crystal medium will be modeled via an orientation-dependent interaction potential between the rigid segments of the bent molecule and the surrounding liquid crystal. This interaction will be taken to be the sum of the interactions of the two separate segments. We first consider these interactions integrated over all positions and averaged over the orientations of the surrounding liquid crystal. For simplicity, we shall take this to be of the Maier-Saupe form, viz"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002268_tcst.2003.809254-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002268_tcst.2003.809254-Figure2-1.png",
+ "caption": "Fig. 2. XTE-46 engine schematic.",
+ "texts": [
+ " The last derivative, , can be calculated by knowing the functional form of the utility function with respect to control . So the controller NN is updated using the (7) and (8) so that (9) Thus, if (7) or (9) are not satisfied then if correspond to the weights of the NN controller, they are updated in a representative manner as (10) This training process is carried continuously over time so as to approximate the dynamic programming equation. The engine model used for the simulation is a XTE46 turbo-fan engine supplied by General Electric (see Fig. 2). The engine model comprises of a single stage high-pressure ratio fan with variable inlet stator vanes, booster with independent hub and tip stator vanes, high-pressure mixed flow compressor, double annular combustor, high- and low-pressure turbines, afterburner, and nozzle components. The complete engine model is represented as a component level model (CLM), that links the state-space models of the individual components in a way that ensures the proper balance of mass, momentum, and energy. The CLM has three states, namely, fan rotor speed (XNL), core rotor speed (XNH) and the average hot section temperature or the metal temperature (TMPC)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001941_eurbot.1997.633569-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001941_eurbot.1997.633569-Figure4-1.png",
+ "caption": "Figure 4: SPIKE",
+ "texts": [
+ " However, a combination of both, the differential and the synchro drive is not possible. An interesting fact that has to be taken into account is that this kind of drive causes accelerations in every direction. This means, that the Stewartplatform must dispose of a t least of six degrees of freedom. VIPER has a maximum velocity of U,,,,, = 0,7? and a maximum acceleration of alnaz = 0.4:. Therefore, both vehicles have approximately the same accelation characteristics but in different directions. 3 The Stewart-Platform In figure 4 the Stewart-Platform [SteG5] SPIKE3 is shown. It was built up as a model of a hydraulic 3Stewart Plattform of the IPR KarlsruhE simulation platform in scale 1:4 compared to the origirial[Wil97]. SPIKE is moved by electric motors with spindle drive, instead of hydraulic cylinders like the original. The accuracy of SPIKE is within 10pm. SPIKE has a maximum stroke length of 150 mm and is controlled by a micro processor. [Egn94] developed n riew form of t,hc basic kincniatics for the platform. 111 figurc 5 tlic attac1inic:nts of the servos of the lower (A1 i "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000697_s0003-2670(00)01081-3-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000697_s0003-2670(00)01081-3-Figure1-1.png",
+ "caption": "Fig. 1. Schematic representation (a) of the squeegee action, paste application and of the screens used for the fabrication of SPE; (b) silver layer; (c) overlay pad; (d) working layer ; (e) Ag/AgCl layer.",
+ "texts": [
+ " From the comparison of the experimental and the theoretical data the tetrahydrate form of the product seems to be the most predominant. The molecular weight of the product, [La(C12H6Cl2NO2)3]\u00b74H2O, is 1010.2. It is insoluble in water, almost insoluble in ether and soluble in acetone. The surface modification of spectroscopic graphite rods was made by direct adsorption of DCPI molecules using a solution of DCPI-Na or [DCPI]3-La in acetone. The detailed procedure was reported elsewhere [24]. The screens allow ink to pass through a pre-determined area, which governs the size and the shape of the print, as illustrated in Fig. 1. SPEs were printed in arrays of eight couples consisting of a working and a reference electrode. Firstly, a layer made of silver acts as the conductive track, secondly a carbon layer (overlay pad) ensures isolation between the solution and the silver. Finally, the Ag/AgCl layer (0.3 cm \u00d7 0.8 cm) was printed over the overlay pad (the left one). Each layer was allowed to dry for 20 min at 60\u25e6C. The working layer (0.3 cm \u00d7 0.8 cm) was printed over the overlay pad (the right one) and produced by mixing 5 g of graphite powder containing 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003554_13552540510601309-Figure16-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003554_13552540510601309-Figure16-1.png",
+ "caption": "Figure 16 (a) Slice with sharp vertical edge with NVS-based cutter trajectory and (b) resulting cut slice lacking the sharp feature, (c) same slice with cusp volume-based cutter trajectory where sharp edge is captured by one such trajectory (d) resulting cut slice retaining the sharp feature",
+ "texts": [
+ " In case of NVS-based checks at regular intervals around the slice contour, there is considerable chance that the vertical sharp edge (Figure 15) would be missed and thus go undetected. Subsequent slicing, cutter trajectory determination and prototyping would result in loss of that sharp feature altogether. While NVS-based checks at regular intervals will have such problems, there are other checks that crowd points in regions of high curvature and rarify their presence in flatter regions. However, it should be noted that they are all discrete checks and the same limitations apply to them as well. Figure 16(a) shows the cutter trajectory for NVS where the sharp vertical edge is falling in between two NVS sections. As a result of this, the prototype is lacking this feature as shown in Figure 16(b). As a remedial measure, NVS-based checks and other 2D sectional checks generally consider an excess of points around the slice contour to detect surface features. This requires higher computational time. Cusp volume check, on the other hand, would detect a sharp edge by the abnormally high value of a particular cusp volume in comparison to that of its neighbouring cusps. In such a case, an extra cutter trajectory line can be introduced to actually pass through the vertical sharp edge to divide the cusp into two (Figure 16(c) and (d)). The algorithm as explained in Appendix 2 can be carried out so that the cusp volumes associated with the two patches come within user defined limit. Needless to say, the incorporation of an extra cutter trajectory in an intermediate slice would require some follow up action that is not discussed here. As a second example, a horizontal sharp edge \u2013 a thin fin for example (Figure 17) \u2013 can also be missed as the first-order check (de Jager, 1996; Faux and Pratt, 1979) would approximate the surface as part of a sphere and thereby fail to recognize the fin (Figure 18)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001198_ip-cta:19960058-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001198_ip-cta:19960058-Figure1-1.png",
+ "caption": "Fig. 1 Shifted und clipped sector segion",
+ "texts": [
+ " A similar problem which has attracted many authors\u2019 interests (see [2] and references therein) is the problem of regional pole assignment. That is, the problem of designing a controller which guarantees that the closed loop poles will be located in a specified region of the complex plane. Regions such as strips, disks, sectors and ellipses are of special concern. This problem is of particular interest when the system to be controlled is uncertain. If the closed loop poles of the system are confined to the shifted and clipped sector in Fig. 1, then the system will achieve a specified damping ratio and degree of stability. However, the problem of pole assignment in such a region is quite hard to address. Alternatively, we can consider subregions of the sector region as in [2]. Of particular interest is the circular region D(a, r ) with centre at -a and radius r 5 a (Fig. 2). By placing the closed loop poles in such a region, not only can one guarantee an upper bound on the damping ratio 5, but also a bound on the natural frequency on and damped natural frequency ad"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001841_irds.2002.1044053-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001841_irds.2002.1044053-Figure6-1.png",
+ "caption": "Figure 6: Grasping a Block",
+ "texts": [
+ " When the limb is heated by the heater with 5[V], it takes 3 minutes to change half of it into soft-deformable state, which is enough large part for deformation. On the other hand, it takes 5 minutes for the limbs to be rigid again from 5O[\"C] when they are cooled by heat release in the air at 25[\"C]. Fig.5-left shows the robot walks when the limbs are in the rigid state. They are rigid enough to use as limbs of the robot. Fig.5-right shows the robot deforms the limbs when they are in the soft-deformable state. They are soft enough to change the shape. 3.2 Grasping a Block Fig.6 shows the robot grasping a block with the deformed limbs. In this time the robot hold on to the block with the deformed limbs, while it could only clip it with the straight limbs. In addition the block is set on a small stand of l[cm] height and the robot can insert the deformed limbs under the block. The deformation is done in the following way. First, when the limbs are rigid, robot moves the limbs and puts their tips beneath the body, because the limbs must be bent inside. Then, the robot changes them into the soft-deformable state and puts the body onto the block with the limbs bent inside because they are so soft not to support the body weight"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002362_itsc.2003.1252673-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002362_itsc.2003.1252673-Figure5-1.png",
+ "caption": "Figure 5 Maneuvering parameters",
+ "texts": [
+ " Effectively, according to the vehicle steering scenario described at the former kction two identical circles with tangent point can be formed. For example, a vehicle moves backward from A to B following a path formed by two circular arcs tangentially connected to each other. Supposing B i s parking bay and A is starting position, thereby parallel parking is achieved (see figure 4). The locations of circle center are depending on the detected parking space and the lateral displacement from the aside car. There are several conditions have to fulfill in order to have a collision-free motion (see figure 5) : 1. The length L must be larger than radius of the circle C,. . 2. Thecar mustatacomect position when begin to parking. The right position is determined by AxandAy. 3. The tuning point AT is depending on different value of Ax and hY. In our methodology the vehicle is always track to the tangential circles. Thereby, the location of circles must be determined. When the parking position is decided, which depends on the length of parking space, the center of c, is vertically pe'rpendicularto the final parking position"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002692_0301-679x(88)90113-2-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002692_0301-679x(88)90113-2-Figure2-1.png",
+ "caption": "Fig 2 Distribution o f contact pressure and geometry o f the O-ring mounted in the seal groove and subjected to sealed pressure. From left to right: O-ring; at a sealed pressure p = O; at p = Pl,\" at p = P2",
+ "texts": [
+ " The experimental verification in this paper is limited to the dependence defining the O-ring lubricating film thickness during out-stroke of the sealed element. Blok's s inverse problem of hydrodynamic lubrication gives the following formula for he: hc = 0.94(rlu/p') \u00b0'5 (3) where !/is the dynamic viscosity of the oil, u the velocity and p' the dp/dx value at inflexion of the pressure distribution curve in the lubrication film. To apply Eq (3) practically it is assumed that p ' = max(da/ds) = a' of the contact pressure distribution (Fig 2) The applicability of Eq (3) for the O-ring net leakage, ?/, was first shown by M/iller 6, who found satisfactory agreement between the ~ values calculated using Eq (3) and those measured experimentally. However, ?/ was investigated over a narrow range of r/u. The present author's research a'2 has shown that considerable differences exist between theory and experiment over the whole range of ~/u used in practice. An attempt to explain these discrepancies was given. Nevertheless, Eq (3) is applied today in engineering practice, and it should be considered as an important achievement of the sealing technology of the 1960s which enables many seal operating problems (leakage, friction) to be solved qualitatively",
+ " The film thickness for O-rings may also be determined from the general hydrodynamic lubrication solution for the linear contact zone of low elasticity modulus which defines the minimum lubrication film thickness, hm, ie - c ~ (5) where w is the load contact pressure per unit perimeter of the O-ring. Solutions given by different authors differ in the values of the constant C and the exponents a and b. The film thickness he1 is found from Eq (5) by determining the unit load w and assuming a stable ratio hm/h\u00a2 = 0.78, as defined by Herrebrugh 8 and confirmed in Ref 7 for O-rings. contact width So (Fig 2) of an O-ring with the surface of the sealed element is sold = 2s + 0.13 for 0.07 ~< e ~< 0.25 (6) which gives the unit load of the contact pressure: rcEs~ w - - 1.05ER(2g + 0.13) 2 (7) 6d For e. = 0.1, w = 0.114ER Substitution of w (for e = 0.1) into Eq (5) as determined by Herrebrugh 8 gives hcl/R = 2.74(rIu/ER) \u00b0'6 (8) The experimental Eq (5) of Dowson and Swales 1\u00b0 gives hc I/R = 2.08(qu/ER) \u00b0'57 (9) Fig 3 shows the experimental set-up used for measuring the leakage of the hydraulic seals. Two identical O-rings TRIBOLOGY international 363 are placed inside the pressure chamber (sealed space)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure13-1.png",
+ "caption": "Figure 13. A symmetric dynamic system with four DOFs.",
+ "texts": [
+ " Group-theoretical approach is more systematic and is completely independent of specifications such as the order of the DOFs, but this is one of the most critical requirements in using algebraic method. In this part, three more examples are presented which involve more practical and large-scale problems. In each example, first, by the means of graph model of the system, symmetry operations and symmetry group of the problem are recognized and then, the group-theoretical approach described above is implemented to factorize the system. The resulting factors are then compared with the canonical form factors of the system. Figure 13 shows a vibrating system with four masses and seven translational springs. Having four DOFs, system belongs to vector space R4 and stiffness and mass matrices will be 4\u00d7 4, as follows: K= \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a2\u23a3 k1+2k2+k3 \u2212k3 \u2212k2 \u2212k2 \u2212k3 k1+2k2+k3 \u2212k2 \u2212k2 \u2212k2 \u2212k2 2k2 0 \u2212k2 \u2212k2 0 2k2 \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a5\u23a6 4\u00d74 and M= \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a2\u23a3 m1 m1 m2 m2 \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a5\u23a6 4\u00d74 Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm For the graph model of this system, as shown in Figure 15(a), it is possible to identify a C2 principal axis and two vertical planes"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001854_cdc.2001.980101-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001854_cdc.2001.980101-Figure1-1.png",
+ "caption": "Figure 1 4 PMz(t)",
+ "texts": [
+ " This method works for a large coupling, hut it cannot he a p plied to the zero coupling case. ID this paper, we will propose a new design method which makes use of the center of oscillation and the twostep linearization. We will also examine the performance experimentally using a non-minimum phase twin-rotor helicopter model. 2 VTOL aircraft model The model x = -u1sin6'+m2cos0 (1) ji = ulcosB+~u2sinO-1 (2) e = u2 (3) has been employed in [Z] for the motion of a VTOL aircraft in the vertical (z,y)-plane(See Fig. 1). The variables I: and y denote the horizontal position and the altitude of the aircraft center of mass, respectively, and 0 the roll angle. The control inputs U,, up are the thrust and the rolling moment. A non-negative coefficient E represents the coupling between the rolling moment and the lateral acceleration of the aircraft, and the approximate model is given by setting E = 0. 0-7803-7061-9/01/$10.00 8 2001 IEEE 217 Remark 1 The system (1) - (3) has unstable zero dynamics described by 8 = (l/e)sinB for the inputs U I , W and the outputs z, y",
+ "2 Controller design We approximate the term Mgwsy of (40) by Mg and the last term of (41) by zero so that the model has the same dynamics as that of the VTOL aircraft model (1)- (3). Then, the next control law can be derived similarly. (46) (47) (53) ~2 = -k328 - kae(0 - 0.) (54) 4.3 Experiments Case 1) A step reference input with the magnitude 40\" is given to the yar angle a t 5 seconds. Namely, the reference input is z,=o , y v = o ( O < t < 5 ) z, = 40\" , v7 = 0 (5 5 t < 25) Figure 16: PM:O(t) Figure 18: AM:z(t) Figure 1 5 PMy(t) \"I'---? 22 - 25. zr = 0 ,yr=O (0 I t c 5) zr = 18(t-5) z, = 360 ,yp = 15sin(t -5) .gr = 15sin20 (5 I t < 25) (25 I t -< 30) The results of the proposed method and the approximate method are shown in Figs. 14 - 17 and Figs. 18 - 21, respectively, where the dotted line shows the reference inputs. Since our experimental setup has unmodeled dynamics such as the viscous friction at the rotation axis and the control delay and saturation at the trust, the good response of Figs. 14 - 17 implies the robust stability of the proposed method"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002598_s0003-2670(02)00490-7-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002598_s0003-2670(02)00490-7-Figure3-1.png",
+ "caption": "Fig. 3. Linear sweep cathodic stripping voltammograms (LS\u2013CSV) recorded with a mercury microelectrode in a 2 M Na2S + 0.1 M NaClO4 aqueous solution at pH = 12; Ed = \u22120.4 V, td: (a) 0; (b) 10; (c) 30; (d) 60; (e) 300 s. Scan rate 50 mV s\u22121. Inset Ipc vs. td,eff and Qc vs. td,eff plots.",
+ "texts": [
+ " It must be considered, however, that with conventional mercury electrodes, distinguishable anodic processes could be observed only for sulfide concentrations larger than 1 mM [22]. This is probably due to the lower flux of the electroactive species associated to the bigger electrodes with respect to the smaller ones. The influence of deposition time, td, on the cathodic voltammetric responses obtained for sulfide ions solutions, was investigated at two different concentrations. The deposition potential, Ed, was set at \u22120.4 V, td was varied over the range 0\u2013300 s, and the potential was scanned towards more negative values at 50 mV s\u22121. Fig. 3 shows a series of linear sweep cathodic stripping voltammograms (LS\u2013CSV) recorded with the mercury microelectrode in a 2 M Na2S+0.1 M NaClO4 solution at pH = 12. From this figure it is evident that for td \u2264 60 s (Fig. 3, curves a\u2013d), a single or two reduction peaks are obtained. The main peak is characterized by Epc values ranging between \u22120.84 and \u22120.73 V, and w1/2 of 10\u201320 mV. The splitting of the cathodic peak could probably be connected with the phase transition of the HgS formed at the electrode surface [49]. For td > 60 s (Fig. 3, curve e), two overlapped broader peaks, at potential between \u22120.900 and \u22120.960, are instead obtained. The cathodic current and charge values associated to the reduction peaks were analyzed as function of the effective deposition time, td,eff , given by: td,eff = td + (Epc \u2212 Ed) v (2) where Epc and Ed are the peak and deposition potentials, respectively, and v is the scan rate; the additive term represents the scanning period during which HgS accumulation continues [28]. The inset in Fig. 3 shows typical Ipc and Qc versus td,eff plots, for deposition time over the range 0\u2013300 s. The Ipc versus td,eff plot is not linear, as expected, whereas the Qc versus td,eff plot is linear, and its regression analysis yielded a correlation coefficient, R2, higher than 0.999. When relatively more concentrated sulfide solutions were considered, i.e. for Cs \u2265 20 M, a single peak was always observed (not shown). However, it became broader and shifted towards more negative potentials, with increasing the effective deposition time",
+ "1 M NaClO4 over the range of scan rates 20\u2013200 mV/s, using Ed = \u22120.4 V and td = 10 s. The peak current against scan rate yielded a straight line with a correlation coefficient of 0.9993. This is in accordance with the occurrence of an electrode process involving species adsorbed on the electrode surface [51]. The main peak and the width at half height remained almost constant, regardless of scan rate, as expected for a reversible process. It is interesting to note that when the main cathodic peak was accompanied by the small peak (Fig. 3), the latter tended to disappear as the scan rate increased. This result is con- gruent with the occurrence of an HgS phase transition [47]. The reproducibility of the cathodic stripping peak at lower sulfide concentrations was also investigated and, for instance, at 1 M Na2S level, peak current and charge were reproducible within 1.5%. Interesting is to note that LS\u2013CSV, which is not a very sensitive technique, can be employed for the determination of the analytical concentration of sulfide at a concentration level as low as 1 M, by using a deposition time of only a few seconds"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001635_3.20858-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001635_3.20858-Figure7-1.png",
+ "caption": "Fig. 7 Finite element model of the antenna and location of piezoelectric actuators.",
+ "texts": [
+ " This system is clearly more complex than the preceding one, and since the antenna structural damping is neglected and the overall system is a free body, it is open-loop neutrally stable. Nevertheless, it will be shown that the equivalent PWM control can be successfully applied also to this kind of system. The antenna studied in the present work consists of a large dish connected to the Shuttle by an aluminum L-shaped flexible truss.8 Figures 6-8 depict the topology and dimensions of the antenna, along with its finite element representation consisting of 95 grid points. Three representative points are marked in Fig. 7, and their dynamic behavior will be used to assess the performance of the system, i.e., node 480 at the corner of the flexible truss, node 751 at the center of the dish, and node 920 on the dish boundary. The flexible truss is considered to be clamped to the Shuttle. All of the elements are supposed to be uniform tubular beams with a cross-sectional area of 200 mm2, Young's modulus equal to 72,520 D ow nl oa de d by C O R N E L L U N IV E R SI T Y o n Fe br ua ry 1 , 2 01 5 | h ttp :// ar c. ai aa ",
+ " Six of them exert forces and moments on all six degrees of freedom of the rigid Shuttle; eight thrusters are placed on the flexible truss: four on the truss corner acting in the X and Y directions and four at the end acting in the Y and Z directions. The corresponding sensors are local displacement and velocity sensors. The control of the dish is carried out by using three reaction wheels, acting along the three axes at the connection with the truss, driven by angle and angular rate sensors and by six piezoelectric layers on the dish's outer radial beams, marked in Fig. 7 as Pi-P6- The piezoelectric layers are supposed to work in couples, one acting as an actuator and one as a sensor, measuring local deformations. For the piezoelectric actuators a lead-lag network has also been devised to provide better performance. Let { u s } indicate the forces acting on the Shuttle, { u t } the PWM forces on the truss, \\ u d ] the moments applied at the dish center, and { u p } the forces exerted by the piezoelectric actuators; by partitioning the measurements vector accordingly, the decentralized feedback control law can be expressed as (40a) (40b) (40c) (40d) The most common performance indexes used for antennas are the nominal pointing error and the average shape error, whose definitions and limits for a large reflector are pointing error = V { t f c ) ' \\ & c } / 3 <0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure14-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure14-1.png",
+ "caption": "Fig. 14 Mesh of the FEM model and radial stress distribution at an intermediate stage of the press-\u00aet",
+ "texts": [
+ " As shown, roughness, materials typologies, lubricant, sliding speed and environmental conditions enter in the experimentally determined friction coef\u00aecient f by means of the constants A, B and C of equation (4), while wheelset geometry, interference and material properties enter directly as input data in the predictive models. The FEM model has been developed by means of the ABAQUS code. It comprehends a part of the axle with the wheel seat and the whole wheel, including the oil injection groove, as shown in Fig. 14. A unilateral contact condition with friction is imposed on the interface surface between the axle and wheel. An elastic\u00b1plastic material behaviour (and therefore the actual stress\u00b1strain diagram) could also be considered with this model, but the corresponding results differ very little from those obtained from the linear elastic hypothesis; the plastic zones are in fact present only for high interference values, but they are always very small and located at the wheel seat chamfer, with a negligible effect on the press-\u00aet curve",
+ " The sum of the reaction loads at the constrained end represents the press-\u00aet load, whose value is expected to increase with the wheel displacement, due to the increasing friction-resistant load. Proc. Instn Mech. Engrs Vol. 218 Part F: J. Rail and Rapid Transit F01203 # IMechE 2004 at HOWARD UNIV UNDERGRAD LIBRARY on February 28, 2015pif.sagepub.comDownlo ded from Several calculations were carried out in order to study the effect of the parameters under investigation. The local effects of the oil injection groove and that of the wheel seat chamfer are visible in Fig. 14, where the radial stresses (i.e. the contact pressures) are plotted for an intermediate stage of the press-\u00aet operation. In particular, the oil injection groove determines, as expected, a local decrease in the contact pressure, while the wheel seat chamfer determines a local increase. This last zone is therefore the most critical for the insurgence of damage mechanisms during the press-\u00aet. The global effects of these two geometrical discontinuities on the press-\u00aet curves are shown in Fig. 17, which refers to the Fiat Ferroviaria wheelset with a sliding speed of 300 mm/min"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003257_tro.2005.844679-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003257_tro.2005.844679-Figure5-1.png",
+ "caption": "Fig. 5. Test for planar cable robot where the outer attachment points of the cables coincide pairwise: Does the line segment from P to Q lie completely within the two reversed triangles? (For this case: No).",
+ "texts": [
+ " Thus, the same geometric criterion applies for force closure in both systems. Example 1: Force closure can easily be checked for the two-pair planar cable robot in Fig. 3(a) as shown in Fig. 4, by extending the lines of the cables and checking whether the line segment from P toQ lies completely within the two reversed open-ended triangles. This geometric criterion may be useful for the synthesis of planar cable robots. More importantly, it is an example of a tool from grasping that carries over to cable robots. Example 2: Shown on the left in Fig. 5 is a cable robot with cable pairs originating from the same point, i.e., the axes of their motors coincide. The corresponding criterion is demonstrated on the right in Fig. 5: Does the line segment from P to Q lie completely in the two reversed open-ended triangles? Note that in this case points P and Q are not located on the mobile platform. This section is based on the spatial antipodal grasp theorem, which can be formulated as follows. Spatial Antipodal Grasp Theorem [11], [12]: A spatial grasp with two soft-finger contacts is force closed if and only if the line connecting the contact points lies inside both friction cones. A grasp satisfying this geometric condition is called antipodal"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002460_63.85913-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002460_63.85913-Figure7-1.png",
+ "caption": "Fig. 7 . Operation of predictive controller: For r = r, A i Y reaches the tolerance area limit in I . The changing of the converter switching status from k to k, leads AiN back into the hexagon; then A i N does not leave it until Ar = f ( k , ) in 11.",
+ "texts": [
+ " If A i N has to be controlled such that it remains within the i,-tolerance region (hexagon), the reaction of the whole system to a switching decision has to be considered before it is \u201cexecuted\u201d by the converter. Certainly excluded should be that (old) KOLAR er al. : ON-AND-OFF LINE OPTIMIZED PREDICTIVE CURRENT CONTROLLERS 455 switching state k which actually makes necessary a converter switching status change (because the relevant trajectory leaves the hexagon). In general more than one of the remaining seven (only six fork = 0 or k = 7) possible switching states will lead the control error back into the hexagon (Fig. 7). Among these a selection has to be made in an optimal sense. One possible optimization criterion is, e.g., the maximization of the dwell time [ t( k , ) ] of the trajectory within the hexagon, weighted by the number of necessary switchings n ( k , k,) to get from the old converter switching status k to the new one k, (Fig. 8 ) . This acts as a switching frequency minimization. But via n ( k , k , ) / t ( k , ) only the local switching frequency is minimized (as, e.g. , in a steepest descent method) and does not necessarily mean that the global minimum will be found (compare I in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003206_iros.2004.1389402-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003206_iros.2004.1389402-Figure5-1.png",
+ "caption": "Fig. 5. Accelcrakd Joints in lacd Momcnlum Suppression Slagc",
+ "texts": [],
+ "surrounding_texts": [
+ "The structures on the knees are small and limited because the legs have to be light to give priority to walking. The structure of the hip joint at which three axes cross is very complex, so strong impact should not he applied to the joint. We use the harmonic drive distinguished by its precision and high reduction ratio in joint structures. Though the harmonic drive has a hack drivahility, it might breakdown if large force exerted against driving power of the motor.\nB. Posirion esrirnarion <$the mbot to thefloor The relative positional relationship between the robot and the floor must be found to detect the beginning of the fall and the current state of the motion. We assume that . the floor is a flat horizontal plane, . the falling motion of the robot is on the sagittal plane,\nand the robot is always in contact with the floor. The joint angles of the robot can he sensed by encoders, and the posture of the torso to the floor can be found from the accelerometer and the gyroscope mounted on HRk-2P through Kalman filter. Therefore we can know the relative relationship between the robot and the floor in principle. The remaining mission is how to find the positional relationship between the landing pan of the robot and the touch down point on the floor.\nTo this end, the following conversion is applied to the geometry of the robot.\ns The convex hull of each link is taken. Each convex hull is simplified to make the minimum depth between vertices larger than 2Omm. . The vertices that have no chance to hit the flat floor when the links are connected are removed.\nThe vertices of the simplified model are illustrated in Fig.2, and the number of the vertices for each link is summarized in Table II.\napproximation of the convex hull of the lower link of the legs. Therefore, the control algorithm also must take this into account.\n111. ALGORITHM\nWe propose the following algorithm to soften the landing of the knees while falling forward. The algorithm consists of four stages.\nDetection of falling over: When the projection of the center of the gravity onto the floor is not included in the convex hull of the soles, it is judged that the robot has staned to fall down. Then the mode of the controller is switched into the falling control mode, and the relative relationshin between the robot and the floor is found by the method mentioned above. Knee bending: The goal of this phase is to make the height of the knees as low as possible before its landing, since it is expected that the potential energy of\nWhile we consider the touch down of the knees to the flat floor, the relative relationship between the robot and the floor can be specified by the angle between the line",
+ "the knee can be smaller which will be converted into kinetic energy. To this end, the knee joints are bended at the maximum angular velocity until 8 becomes smaller than a pre-determined threshold (Fig.4).\nFit. 4. Knee bending\nBraking of the landing speed: The hip pitch joint, waist pitch joint and shoulder pitch joint are moved such that 0 should be braked. Landing: The feedback gains of the joints control are made one-tenth to make the joints compliant to the impact of the landing.\nThe details of the braking of the landing speed are as follows. The angular momentum of the robot around the tip of the feet increases while falling forward as\n(1) C = P ( ~ ) x mg: where C is the angular momentum, pft) the position of the center of the gravity, and m the total mass. C can be represented by\nwhere IO is the moment of inertia. When the hip pitch joint, waist pitch joint and shoulder pitch joint are driven actively, the angular momentum of the robot around the tip of the feet should be kept constant since no extemal force is generated. See FigS. Let A0 be the deviation of 8 caused by the motions of the joints, then\n(3)\nc = loa, (2)\n0 = Ioai + I ,& + 1 2 8 2 + I3&,\nwhere 8,,i = 1,. . . , 3 is the joint angle of the hip pitch, waist pitch and shoulder pitch respectively and Ii the moment of the inertia for a,, i = 1 , . . . , 3 respectively. Taking the sum of both sides of Eqs.(Z) and (3), we obtain\n(4)\nwhich means that ),can be braked by controlling ai. From Eq.(3), the desired can be given from a desired ABre\u2019\nc = I0(S +A%) + I101 + 1 2 8 2 + 1383,\nby\nwhere,()? stands for the pseudo inverse of a matrix. Let 8, = 0 + A@, the braked angular velocity, then Eq.(S) can be rewritten by\nwhere\nK1 = y, 1<2 = -70,\nwhere sup() stands for the supremum. Here, the supremum is determined by taking several joint values, because the values do not vary much.\nWe chose y so that S y remains within actual speed limits. Note that K2 depends on 8, but it is,fixed to a constant value, and that the magnitude of (K10o + Kz) is clipped at a specified value.\nIv. EVALUATION OF THE ALGORITHM\nA. Sin~ularions We use the dynamics simulator of OpenHRP [6] to simulate the proposed method. The dynamics parameters and geometry of HRP-ZP are used in the simulations. The integration interval of the dynamics simulation is 1 msec, and the outputs of the controller are updated every 5 msec.\nThe initial posture of the robot is the standing with a slight bending of the knees(Fig.6). Then a forward force with 100[N] is applied to the torso of the robot for 1.0 sec. When the robot s t a s to fall forward, the mode of the controller is switched from balancing mode to falling mode (Fig. 7) and the knees start to bend immediately.",
+ "In the simulation, 0 can be found from the attitude of the body and the vertices of the simplified convex hull. When 0 reaches the first threshold O', the braking of the landing speed stam(Fig. 8). 8' is set to 20 [deg] in the following s@ulations. While the braking is applied, is decreased to 00. When 00 reaches the second threshold 02, the controller goes into landing mode(Fig. 9). O2 is set to 10 [deg] in the simulations.\nThree kinds of the simulations are examined. The first one is the falling without any control, the second one is with the knee bending, and the third one is with the knee\nbending and braking. Fig. 10 shows the trajectories of 0 or Bo when braking is applied. The trajectories are not smooth,\nsince 0 is found by the relative relationship between the vertices on the knee and the floor and the representative vertex may change.\nWhen no control is applied e increases rapidly and the knees hit on the floor with 0 = .5.08[rad/sec]. The trajectory is shown as 'without falling over control' in Fig.10. The landing posture is shown in Fig.] 1 which looks very dangerous to the robot.\nWhen the knee bending is applied without the braking, 6 increases more rapidly in the initial phase than the previous"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001177_0954406011524711-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001177_0954406011524711-Figure8-1.png",
+ "caption": "Fig. 8 Model of a ball impacting on a freely suspended racket, containing a spring and a damper in parallel (the ball), another spring in series (the stringbed)and a rigid body (the racket)",
+ "texts": [
+ " These parameters are experimentally determined and are dependent on the ball impact velocity. In an actual tennis stroke the racket is supported by the player\u2019s hand. However, it is very di cult to replicate this method of support in a laboratory. As mentioned previously, Brody [8] found that supporting a racket freely was the most valid method of simulating a player\u2019s grip in a laboratory. The ball was modelled as spring and damper in parallel, with the ball properties kb and cb , and the stringbed is modelled as a simple linear spring with stiVness ks , as illustrated in Fig. 8. The racket frame is modelled as a rigid body of mass mr and moment of inertia around the centre of mass (perpendicular axis) Ir . The ball impacts at a distance, d, from the centre of mass and the displacement of this point on the racket is xd . The linear and angular displacement of the centre of mass are de\u00aened as xr and \u00acr respectively. It was assumed that the force acting on the stringbed is applied to the racket frame as a point load, not as a distributed force. Therefore the force balance is F \u02c6 mb xb \u02c6 cb\u2026 _xb \u00a1 _xs\u2020 \u2021 kb\u2026xb \u00a1 xs\u2020 \u02c6 ks\u2026xs \u00a1 kd\u2020 (10) Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001032_1999-01-0974-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001032_1999-01-0974-Figure1-1.png",
+ "caption": "Figure 1. Piston Ring Free Body Diagram",
+ "texts": [
+ " \u2022 Friction effects are from oil shearing only. It is assumed that the following magnitudes are known: \u2022 The instantaneous piston speed (Vp) \u2022 The oil viscosity (\u00b5) \u2022 The pressure behind the ring (P), including pressure due to ring tension and gas pressure \u2022 The basic ring geometry (c, a, and L), shown in Fig(1) The Reynold's equation, considering one-dimensional, incompressible flow will be used to calculate the oil film thickness and oil film pressure. The form of the equation is: (3) Referring the Fig. 1, the ring geometry is considered to be two parabolas, tangent at the point of minimum oil film thickness. The oil film thickness h, when considering this ring profile is: h = hx + ho (4) where: (5) and ho is the minimum oil film thickness. Once the oil film thickness and the oil film pressure are found by solving Eq. (3), the friction force may be obtained. Details are given in [26]. Piston Ring Simplified Model \u2013 The Stribeck curve (Fig. 2) illustrates the dependency of the friction coefficient f on the duty parameter S",
+ " This represent the contribution of the last term (\u2202h/\u2202t) in Eq.(3). This produces a loop in the Stribeck diagram, introducing a small amount of nonlinearity in the curve. A linear regressed relationship of the curve can be expressed as follows: ln(f) = m\u00deln(S) + ln(B) (6) The slope and y-intercept of the appropriate Stribeck curve are m and ln(B) respectively, depending on the ring\u2019s geometry. The curvature of the ring is defined as the ratio of the ring profile recess \u201cc\u201d at the ring edge to the height \u201ca\u201d of the parabolic profile (see Fig. 1). It has been found that varying the height L of the ring while maintaining a constant ring curvature does not influence the dependency of the friction coefficient on the duty parameter significantly [29],[30],[31], but there is a strong relationship between the ring\u2019s curvature and this dependency. Considering this, the model generates unique Stribeck curves for a given ring\u2019s geometry by varying the curvature of the ring. A linear regression has been performed to relate ln(f) to ln(S). When varying c/a from 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002931_te.2004.825528-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002931_te.2004.825528-Figure10-1.png",
+ "caption": "Fig. 10. (a) Explosion and (b) assembly of the designed prosthesis.",
+ "texts": [
+ " After these two parts are completed, the students can integrate the circuits into a single-board system by soldering. Fig. 9 depicts the resulting circuit board. Making the mechanism of the prosthesis is a rather difficult part of the experiment since most students who major in EE are not competent machinists. To reduce the impact of this weakness, the components of the prosthesis are all made of aluminum or acrylics, since these materials are easy to reprocess and allow components to be made on a simple workbench. Fig. 10 shows the AutoCAD files, named explosion.bmp and assembly.bmp, which are the exploded and assembly drawings, respectively, of the components of this EMG prosthesis. The components of the prosthesis mechanism include a fixed part (A), a movable part (B), a linkage (C), and a main body (D). Using the actual-size data provided by the instructor, students can easily make all the parts of the prosthesis using hand tools. Furthermore, the students can draw the components using AutoCAD and convert the drawing to a DXF file for processing by a computer numerical control (CNC) milling machine"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.5-1.png",
+ "caption": "Figure 4.5. A constant vector ro 1 in the rotating platform frame cp has a nonzero time derivative in the fixed frame <1> due to the rotation of cp relative to <1>.",
+ "texts": [
+ "17c ), we find the solution dx(A, t) dt (i sin f3 + IP cos /3) i +~sin f3 j + (i cos f3 -IP sin /3) k. (4.17d) This is the velocity of A as seen by an observer situated in the machine foun dation l/J but referred to the moving frame ({J for convenience; it is the (absolute) velocity of A relative to 1/J. The physical ideas illustrated here will be expanded further on. In preparation for our future studies, the student should find it helpful to deter mine the derivative of ( 4.17b) in the frames ({J and 1/J. D Example 4.3. An electric motor M shown in Fig. 4.5 is attached to a platform that rotates with a constant angular speed of 10 rev/sec about aver tical axis. The motor drives a gear G at a constant angular speed w 1 = 300 rev /min relative to the platform. (a) Find the time derivative of the angular velocity vector ro 1 in the fixed spatial frame 1/J. (b) What is & 1 in 1/J? (c) What are these derivatives in the moving frame ({J fixed in the platform? Refer all vectors to the frame ({J shown in Fig. 4.5. Solution. (a) The moving frame ({J = { 0; ik} is fixed in the platform with j directed along the center line of the motor axle. Thus, with modified units and referred to the moving frame ((J, rof = 20n:k rad/sec is the constant angular velocity of the platform frame ({J relative to 1/J, and ro 1 = lOn:j rad/sec is the angular velocity of the gear relative to the platform. It is clear from (4.10) that in the rotating ({J-frame broJ!bt=O; and it follows from the general rule (4.11) or by (4.12) that ( 4",
+ " (c) Because ro 1 is a constant vector in qJ, ali of its derivatives vanish in q>: bnw 1/btn = 0, as we saw above for n = 1, 2. This completes the problem solution. We have determined in ( 4.18a) the angular acceleration ro 1 in frame C/J when the angular velocity vector ro 1 is referred to the reference frame qJ which is turning with angular velocity ro1 in C/J. However, as shown in Example 4.1, we may obtain the same results by referring ro 1 to the preferred frame C/J. First, we must write the moving basis ik in terms of the fixed basis Ik. From the geometry of Fig. 4.5, we have i = cos 8 I + sin 8 J, j = cos 8 J - sin 8 I, k=K. ( 4.18c) Thus, referred to C/J, we have the general formula ro 1 = 10nj =JOn( cos 8 J- sin 8 I) rad/sec; ( 4.18d) and with e = lrotl = 20n radjsec, we obtain ro 1 = -lOnO(sin 8 J +cos 8 I)= -200n2i radjsec2, ( 4.18e) in which the change of basis back to qJ is left for the reader. This is the same as ( 4.18a ). Construction of ro I is left to the student. This method illustrates again that an important advantage of the procedure developed in this chapter of referring a vector to a moving frame is that unnecessarily complicated geometrical considerations may be avoided, particularly in three-dimensional problems, and the calculations are reduced in large measure to easy vector algebraic computations",
+ "25a) ro,o = ro\"\u00b7\" 1 + ro\" 1,o; O)n-1,0 = ron-l,n- 2 + ro,_ 2,0; Upon substituting the second of these into the first, and so on, we reach the important result stated in ( 4.24 ). In particular, for the special case n = 3, we see in the construction above and from ( 4.24) that (4.25b) The composition rule ( 4.22) plainly represents the generalized kinematic chain rule for angular velocity vectors. Some applications of these important results are presented below. Example 4.4. Recall the earlier Example 4.3 of a motor-driven gear mounted on a rotating platform shown in Fig. 4.5. Therein, the constant 244 Chapter 4 angular velocity of the gear relative to the platform is given as ro 1 = 1 Onh rad/sec; and ro1 = 20nk 1 rad/sec is the constant angular velocity of the platform relative to the ground. Determine the total angular velocity of the gear relative to the ground, but referred to a frame fixed in the platform. Label and identify carefully all references frames used. Solution. The problem statement suggests that three imbedded reference frames are relevant. The frames may be labeled in any convenient manner"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003352_j.tecto.2003.11.009-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003352_j.tecto.2003.11.009-Figure3-1.png",
+ "caption": "Fig. 3. Geometrical elements of a curve composed by a quarter of an ellipse and a line segment. This curve is used to fit isoclinal folds.",
+ "texts": [
+ " Since conic sections only range from chevrons to elliptical shapes, some natural folds cannot be fitted by a conic curve with a common middle point. In particular, cuspate folds or isoclinal folds, except those approaching a quarter of an ellipse, cannot be fitted by a conic. Isoclinal folds can be fitted by a function composed by a quarter of an ellipse, as defined by Eq. (1) in the interval [0, x0], and a line segment (x = x0, within bV yV y0) of length c that is a prolongation of the ellipse arc (Fig. 3), as was proposed by Bastida et al. (1999). This function allows us to extend the range of folds with a possible fit as far as the box shape. According to Bastida et al. (1999), the c value to fit an isoclinal fold by the middle point method is given by: c \u00bc y0 yM 1 ffiffiffi 3 p 2 : \u00f09\u00de 4. Graphical classification of folded surface profiles using conic sections The range of fold morphologies that can be represented using these functions can be visualised through the use of an h vs. e diagram (Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003989_cimsa.2004.1397257-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003989_cimsa.2004.1397257-Figure2-1.png",
+ "caption": "Fig. 2. Single Link Flexible Robotic Manipulator",
+ "texts": [
+ " Thus the system will grow eventually. However, at any time instant if the system operating conditions approaches a previously established value, then those corresponding centers are used. Due to the above-mentioned dynamic RBFNN approach the curse of dimensionality issue is addressed. lV. POSITION CONTROL OF SINGLE LINK FLEXIBLE MANIPULATOR The proposed approach is applied to a single link flexible manipulator for tracking the angular position of the desired trajectory for two distinct cases. Figure 2 shows a single link flexible manipulator, which is modeled based on the physical parameters. The model details of the manipulator are presented in Appendix A. A command signal, which is applied for eight seconds, is tracked, and the tip load is varied arbitrarily at different time instant. The variation in the tip load contributes to the mode swings in the model. Different types of such mode swings are applied and the proposed scheme is tested for each case. The focus here is to compare the capability of the proposed intelligent controller with the traditional MRAC with the single reference model and varying reference model(s) to control such changes"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002923_acc.2005.1470620-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002923_acc.2005.1470620-Figure6-1.png",
+ "caption": "Fig. 6. velocity sectors for the ECAV and the phantom point",
+ "texts": [
+ "5 is for such a set of constant bounds which does not result in the phantom being contained within its velocity rectangle. As is clear from Fig.5, for the given set of initial conditions the target waypoint of the phantom is in that region the phantom can never reach. It is clear that the time varying nature of each of the bounds is critical for this particular approach to the problem. Now we consider constraints placed through bounds on the ground speeds of the ECAVs and the phantom point. Such constraints lead to the feasible velocity sectors being annular as illustrated in Fig.6. To allow more flexibility on the initial conditions, the ECAV, the phantom point and the radar (OEP) are constrained to be inline only at the beginning of each time step of the algorithm at which point the direction and speed are set for both the phantom point and ECAV. This collinearity constraint requires ( ) sin sin ( ) r t V R t W (10) A Necessary condition for solutions for (10) to exist is, ( ) sin 1 ( ) r t V R t W (11) where ,V W are the ground speeds of the phantom and ECAV respectively"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure6-1.png",
+ "caption": "Figure 6. Factors of the system with the form II symmetry and its factors: (a) C; and (b) D.",
+ "texts": [
+ " Subspace V (1): 2 = (k1 + 2k2)/m and the subspace V (2): 2 = k1/m It should be noted that by solving characteristic-value problem of the original problem, the same natural frequencies would be attainable. The matrices of the system with canonical form II symmetry in which: AK =[k1 + k2] and BK = [\u2212k2] are decomposed into the submatrices C and D, as follows: CK =AK + BK = [k1] and DK =AK \u2212 BK =[k1 + 2k2] It can be shown that the factors C and D as new subsystems resulted from original system. These factors are depicted in Figure 6. In this figure, the correspondence between decomposition of the system and its graph model can be seen. Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm In symmetry of form III, the axis of symmetry passes through at least one joint of the system. A simple example of such a system is shown in Figure 7. Consider the planar two-storey frame of Figure 7(a). The second storey of this frame consists of two separate rigid diaphragms with the mass of m2 which are connected together with an axial member, modelled as the spring k3"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003686_tmag.2004.824549-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003686_tmag.2004.824549-Figure2-1.png",
+ "caption": "Fig. 2. Radial and tangential components of the force.",
+ "texts": [
+ " The total simulation time was 1 s with a constant time step of 0.05 ms. In the spectral analysis, the number of sample points was 8192 in fast Fourier transform (FFT) and the length of the signal 4 s, by adding the zero level at the end of the sample to increase the frequency resolution of the frequency response of the forces. If the forces are divided into a radial component in the direction of the shortest air gap and a tangential component perpendicular to the radial one, the components are almost independent of time. Fig. 2 illustrates the force components. The advantage of the impulse method is that, from one simulation, the forces and harmonics are reached for a wide whirling frequency range. The use of the impulse method to calculate the electromagnetic forces is verified by conventional calculations for a strongly saturated induction motor in [11] and is validated by measurements in [12]. The results of the verification and validation show very good agreement. III. RESULTS A four-pole 15-kW induction motor was chosen as a test motor"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002883_robot.2004.1302491-Figure13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002883_robot.2004.1302491-Figure13-1.png",
+ "caption": "Fig. 13 Measurement System of Propulsion",
+ "texts": [
+ " Fig.11 shows the swimming motion in the water surface. Fig.12 shows the swimming motion in the vertical direction reaction in water by changing buoyancy of the microrobot. Actuator ICPF ,4ctuator (0.2*3*15) Electricity (e.g.4V, 0.15A) VI. EXPERIMENTAL RESULTS n 5 3 - 3 2.5 0 c z 1.5 0 1 0.5 .g 0 ' \" ' \" ' . . ' \" \" ' 2 c4 0.10.20.30.40.50.60.70.8 1 2 3 4 5 6 7 8 9 10 frequency of input voltage (Hz) We made the swimming experiments of the prototype microrobot using a measurement system shown in Fig.13. The propulsive forces for various frequencies were measured using a laser displacement sensor, an electric balance and a copper beam. The copper beam is soft enough to be bent by the propulsive force. The electric balance is used for the force evaluation. We also measured the propulsion speed for various frequencies using a high-speed camera. The average value of over 20 data is used as the final test data. By changing the frequency from 0.2Hz to 5Hz at 2.5 voltage input, the experimental results of average propulsive force, and average speed are shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001980_robot.1995.526028-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001980_robot.1995.526028-Figure1-1.png",
+ "caption": "Figure 1 - An Enveloping Grasp",
+ "texts": [
+ " We also allow contact with one or more fixed surfaces (such as a palm or torso), and explicitly take into account the (possibly stabilizing or destabilizing) effect of an external force such as gravity. Note that we use \u201cfingers\u201d as a generic term to represent any finger, fixture, or link in point contact with the grasped object. Our procedure is particularly applicable in the case of enveloping grasps; it is, however, applicable in all grasps, enveloping or not. 2. Modeling and Problem Formulation Consider Figure 1. Let nf be the number of independent fingers in contact with the grasped object, and let \u2018nc be the number of contacts on finger i. The superscript \u201ciJ\u2019 is used to denote the j f h contact on the ith finger. Further, let np be the number of contacts with fixed surfaces, and let the superscript \u201cl\u201d denote the l fh contact with a fixed surface. In Figure 2, we consider a contact between a grasped object and a finger. If the bodies are perfectly rigid we can define the contact point which is the coincidence of two points, iJJoB fixed to the grasped object and i\u2019JoA fixed to the finger"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003057_0141-0229(86)90134-1-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003057_0141-0229(86)90134-1-Figure1-1.png",
+ "caption": "Figure 1 A, d.c. cyclic voltammogram at a 4 mm diameter pyrolyt ic graphite electrode of ferrocene monocarboxylic acid (200 #M) in Tris--HCI (50 mM) buffer pH 7.0 containing MgCl= (20 mM) and glucose (10mM) at ascan rate of 1 mVs -1 a n d 2 0 \u00b0 C . B , A s f o r A but wi th the addit ion of glucose oxidase (11 #M) and subsequently hexokinase 20 U ml -I . Finally, ATP (10 mM) was added and voltammogram B reverted to voltammogram A",
+ "texts": [
+ " cyclic voltammetry to study enzyme catalysed radox reactions which form the basis for the development of biosensors 12 and biofuel cells. 13 Particular attention has been given to the use of ferrocene derivatives as electrochemical mediators. 6'14'1s Here, cyclic voltammetry is used to demonstrate the effect on the electrochemically coupled glucose oxidase catalysed reaction (equations 6 and 7) of hexokinase in the presence of its substrates (equation 2). The cyclic voltammogram of ferrocene monocarboxylic acid in buffer containing glucose (10 mM)is shown in A of Figure 1. This voltammogram is consistent with the electrochemically reversible ferrocene-ferdcinium ion oneelectron redox couple, (E1/2 = 280 mV vs SCE; AEp 60 mV). Addition of glucose oxidase, B of Figure 1, causes a marked increased in the anodic current, consistent with electrochemically coupled oxidation of glucose , 6 as shown in equations (6) and (7). Upon addition of hexokinase (20 U ml -~ ) to the cell no change in the shape of the voltammogram occurred; however, when ATP (10 raM) was also added catalytic behaviour was no longer observed and the voltammogram returns to that of the reversible electrochemistry of the ferrocene, curve A of Figure 1. This observation is consistent with complete phosphorylation of glucose, equation (2), thus removing it as a substrate for the glucose oxidase catalysed reaction. In this experiment only sufficient ATP to phosphorylate all of the glucose initially present was used; consequently, by further addition of glucose the catalytic reaction, curve B of Figure 1, could be restored. Having demonstrated that this coupled reaction sequence for detecting ATP worked in a homogeneous system, it was feasible to study the glucose enzyme electrode, 6 first as an ATP sensor and then for monitoring creatine kinase activity. Glucose enzyme electrode The current-time response of the glucose enzyme electrode in a cell containing 1 ml buffer with glucose (10 #mol) and hexokinase (20 U) was allowed to reach the steady-state ca. 60-90 s. 6 (The initial steady-state current was 10/IA; this corresponds to a rate of glucose consumption by the enzyme electrode of ca"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000980_9.310037-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000980_9.310037-FigureI-1.png",
+ "caption": "Fig. I . A model of car.",
+ "texts": [],
+ "surrounding_texts": [
+ ".. System. Moscow-MIR, 1978.\n[IO] V. I. Utkin, \u201cVariable structure systems with sliding modes,\u201d lEEE Trans. Automat. Control, vol. 22, pp. 21 1-222, 1977. [ 1 I ] V. I. Utkin, \u201cVariable structure systems-present and future,\u201d Auto. Remote Contr., pp. 1105-1 120, 1983. [I21 V. I. Utkin and K. D. Yang, \u201cMethods for construction of discontinuity planes in multi-dimensional variable structure systems,\u201d Auto. Remote Contr., pp. 14661470, 1978. [I31 V. 1. Utkin, \u201cEquations of the sliding regime in discontinuous system,\u201d Auto. Remote Contr., pp. 211-218, 1972. [I41 J. J. E. Slotine and S. S. Sastry, \u201cTracking control of nonlinear systems using sliding surface with application to robot manipulators,\u201d Int. J. Control, vol. 38, pp. 465-492, 1983. [ 151 A. F. Filippov, \u201cDifferential equations with discontinuous right hand sides,\u2019\u2019 Am. Math. Soc., vol. 62, pp. 199-231, 1964. [I61 Y. Y. Hsu and W. C. Chan, \u201cOptimal variable structure controller for DC motor speed control,\u201d in Proc. Inst. Elec. Eng., 1984, pp. 233-237. [I71 R. A. DeCarlo, S. H. Zak, and G. P. Matthews, \u201cVariable structure control of nonlinear multivariable systems: A tutorial,\u201d in Proc. IEEE 1988, 1988, pp. 212-232. [ 181 J . J. E. Slotine, \u201cOn modeling and adaptation in robot control,\u201d in Pmc. IEEE Int. Conf: Robotics and Automation, 1986, pp. 1387-1392. [I91 J. S. Reed and P. A. Ioannou, \u201cInstability analysis and robust adaptive control of robotic manipulators,\u201d IEEE Trans. Robotics and Automation, vol. 5, pp. 381-386, 1989. [20] T. C. Hsia, \u201cAdaptive control of robot manipulators-A review,\u201d in Proc. IEEE Int. Conf: Robotics and Automation, pp. 183-189, 1986. [21] S. Dubowsky and D. T. Desforses, \u201cThe application of model referenced adaptive control to robot manipulators,\u201d ASME J. Dynamics Sys., Meas., Contr., vol. 101, pp. 193-200, 1979. [22] J. J. Craig, P. Hsu, and S. S. Sastry, \u201cAdaptive control of mechanical manipulator,\u201d in Proc. IEEE Int. Conf: Robotics and Automation, 1986,\n[23] J. J. E. Slotine, \u201cSliding controller design for nonlinear system,\u201d Int. J. Contr., vol. 40, pp. 421-434, 1984. [24] J. J . E. Slotine and W. Li, \u201cOn the adaptive control of robot manipulators,\u201d presented at the ASME Winter Annual Meeting, Anaheim, CA, pp. 51-56, 1986. [25] -, \u201cAdaptive manipulator control: A case study,\u201d in Proc. IEEE Int. Conf: Robotics and Automation. 1987, pp. 1392-1400. [26] -, Applied Nonlinear Control. Englewood Clifs, NJ: Prentice-Hall, 1991. [27] P. Ioannou and J. Sun, \u201cRobust adaptive control,\u201d class notes of EE685, USC, 1992. [28] L. W. Chen and G. P. Papavassilopoulos, \u201cRobust optimal force variable structure and adaptive control of single-ann and multi-arm dynamics,\u201d Ph.D. dissertation, Department of Electric Engineering-Systems, Univ. Southern Calif., 1991.\npp. 190-195.\nI. INTRODUCTION Let us consider a car moving forward and backward with a lowerbounded turning radius R (without any loss of generality, we assume R = 1) and an upper-bounded velocity. The position and the direction of the car are, respectively, defined by the coordinates ( x . y) of the reference point and the angle 0 between the abscissa axis and the main axis of the car (see Fig. 1). So, the car is completely defined as a point (z, y. 8 ) in the configuration space R2 x SI. If we assume that the linear velocity is constant, the motion is defined by the control system\nwith Iul( t ) l = 1 and I I L Z ( ~ ) ~ 5 1 where u1 and 7 ~ 2 are, respectively, the linear and angular velocity of the car. Such a differential system expresses kinematic constraints which characterize the nonholonomic nature of the car [4]. This is the Reeds and Shepp model.\nInitially this model has been introduced by Dubins [3] for a car that moves only forward (i.e., t i 1 1). He determines a sufficient family of shortest paths.\u2019 Using this result and the result of Melzak [6], Robertson [lo], and Cockayne and Hall [Z] provide the set of accessible positions for the model of Dubins (i.e., ul = 1).\nThe problem of finding a shortest path between two configurations when backward motions are allowed ( 1 1 1 = +l) has been set by Reeds and Shepp in [9]; it has been completely solved after a sequence of different works 111, [9], [ I l l , [12].\nThis paper solves the following problem:\nHow do we compute the set of reachable positions from the origin by path of a given length when the final direction of the car is not specified?\nIt is solved in two steps: among all the paths linking an initial position with fixed direction of the car to a final position with free direction, we point out a shortest one. Then, from the shortest path expression, we obtain the complete analytical description in the plane (0. .T: y ) of the set of positions reachable from the origin by a path of length lesser than some given value. Section I1 presents the state of the art on Reeds and Shepp\u2019s problem. Section I11 shows how to apply the Pontryagin Maximum Principle (PMP) to compute a sufficient family of optimal paths. This family is then reduced by\nManuscript received March 4, 1993; revised August 31, 1993. This work was supported by the ECC Espirit 3 Program within Project 6546 PROMotion.\nThe authors are with LAASCNRS, 7 Avenue du Colonel Roche, 31077 Toulouse, France.\nIEEE Log Number 9401680. \u2019 i.e., a family rich enough to always contain a shortest path to link any two\nconfigurations.\n0018-9286/94$04.00 Q 1994 IEEE",
+ "direct geometric arguments. Section IV presents the synthesis of the optimal paths: i.e., we give the closed-form expression of the optimal control law that steers the system from the origin to any position. Finally, Section IV presents the set of positions reachable from the origin by a path of length lesser than a given value. Our work is based on Optimal Control Theory and uses previous results of Reeds and Shepp [9], Sussmann and Tang [12], and Boissonnat et al. [I]. We complete our proof with geometric arguments.\nRemark 1: For the Reeds and Shepp problem, the synthesis of optimal paths computed in [ 111 provides a partition of the space2 R2 x [-n, n] induced by the shape of the path reaching the origin. In [ 5 ] , Laumond and Soubres have studied the metric induced by the shortest paths for this model of a car. By using the shortest path synthesis, they compute the ball B,I for any value of the radius d. The set of reachable positions by path of length d computed in Section V, is the projection of the ball Bt3d in the horizontal plane (0. .r. y). The method used to compute the partition of the plane (Section IV), and the set of accessibility (Section V) is similar to the methods developed in [ 5 ] , [ 111. Nevertheless, for this two-dimensional problem the transversality conditions given by the PMP (Section 111-B) provide a reduction of the sufficient family. This simplifies the problem.\n11. THE REEDS AND SHEPP\u2019S PROBLEM\nSince 1990, from the pioneering work of Reeds and Shepp [9], several contributors [ 11, [ I I], [ 121 have studied the problem of finding the shortest path between any two configurations.\nNotation: The paths are described using Sussmann\u2019s notations: ( S ) denotes a straight line segment and (C) an arc of a circle with radius 1. The symbol I between two letters indicates the presence of a cusp. The subscripts are positive real numbers referring to the length of the corresponding pieces. We also use 1 for left turn and r for right turn and the superscript + ( - ) denotes forward (backward) motion. When these superscripts are used, the cusp symbol I is redundant and does not appear.\nFirst, using geometric arguments, Reeds and Shepp have proved that the shortest path can always be chosen among 48 simple sequences of at most five pieces, with a piece being a straight\n21n [ I I ] it is shown that it IS equivalent to consider R2 x S\u2019 or R2 x [-T, TI.\nline segment (S) or an arc of a circle (C ) of radius 1. These simple paths contain at most two cusps. Recently, this problem has been studied within the Optimal Control Theory framework by Sussmann and Tang [12] and Boissonnat et al. [l]. They independently give a new proof of Reeds and Shepp\u2019s result by using PMP and also refine it. Particularly, Sussmann and Tang have reduced the number of the sufficient family elements to 46. Finally, Soubres and Laumond [ 111 achieve the synthesis of the shortest path. New limitations appear for the validity of each type. By combining all these conditions, the search for an optimal path can be restricted to the sufficient family as shown in (1) at the bottom of the page. We will call every member of this family a Reeds and Shepp\u2019s path.\n111. THE FREE FINAL DIRECTION PROBLEM\nA. Definition\nLet us denote by A0 the line parallel to the @-axis passing by (2, y, 0) in the configuration space R2 x S1. The final configuration is free on A0 and the final direction 8\u2019 will appear as the result of the shortest path characterization. Thus, our problem can be restated as:\nFind a shortest path between the origin (0, 0, 0) and the line Ao.\nIt is clear that a path reaching (I. y, 8 \u2019 ) optimal for our problem (i.e., optimal among all admissible paths starting from (0, 0, 0) that reach AS) is optimal among all the paths that reach the configuration (s, y. 8 * ) . As there is always a Reeds and Shepp\u2019s path optimal between two entirely specified configurations, there is always a Reeds and Shepp\u2019s path optimal for our problem.\nThis remark allows us to search for an optimal path in the sufficient family ( I ) only.\nB. Maximum Principle and Transversality Condition\nWhen an optimal control problem has some free boundary conditions, the Pontryagin Maximum Principle [8] provides as many additional conditions, called transversality conditions, as free boundary conditions are. Under some regularity assumptions, these conditions mean that if an initial (final) state is free on a given manifold ,U then the adjoint vector 9 at the initial (final) time is orthogonal to the tangent hyperplane of M at the initial (final) state. Since [U 1 I = 1, searching for the shortest paths is equivalent to minimizing the time. Now, let us construct the Hamiltonian function \u2018H\n\u2018H = 90 + 91 cos 8 11 1 + 9 2 sin Ou 1 + 9 3 r r z (2)\nand the differential adjoint system i , = -E = 0 9, = -E = (1\n+ 9 1 is constant =+ 9, isconstant\n9, = -- : - !FL sinoul - !F,cosHrr1 = - 9 2 . i - .",
+ "Here, the third differential equation is integrable and we obtain Pig(t) = @ 1 y ( t ) - ! F z x ( ~ ) +93(0) . Again, the Hamiltonian function Fig' 3' A piece I is Optima' can be written as\nwith\nd1 = !P1 cos19 + Q2 sin8\nand\n4 2 ( t ) = !F3(t) = P l y ( f ) - 9 2 X ( t ) + @3(0).\nFirst, we summarize the results obtained in [I], [12]: The constant QO is never zero on an optimal path, 61 and 4 2 are not simultaneously zero, Then, t f being the final time, we have two kinds of paths: -Paths with u1 singular over [0, t , ] and for which u2 does not\nswitch. These are the paths C I C I C. -Paths with U 1 bang-bang over [0, t r ] . We use the fact that the\nHamiltonian function 1-I is zero along an optimal path. Then, d l = 0 implies that QO + 42u2 = 0. From the expression of d2, this equality defines two parallel lines in the plane (x, y). As in [I] , we call them D+ (respectively, D - ) when u2 = 1 (respectively, u2 = -1). These lines are symmetric with respect to the line Do defined by $2 = 0. DO supports the straight line segments and the points of inflection and the cusps occur perpendicularly on D+ or D-. These paths remain between D+ and D- (see Fig. 2 and [I] for details).\nHere, the initial state is entirely specified, and the final state is free on the line &. Then, the transversality condition expresses that the adjoint vector 9 at the final time t f is orthogonal to that line. In other words\n(4)\nFirst, identifying the transversality condition (4) with the expression of 42, we obtain the following lemma.\n9 3 ( t f ) = * i y ( t f ) - * . L X ( ~ J ) +*3(0) = 0.\nLemma 1: The final point is on the line DO. On the other hand, from the transversality condition, we have the following lemma. Lemma 2: TL cannot be singular on an optimal path. Consequently the Reeds and Shepp's path C I C I C is not optimal here. Proof: From the Maximum Principle [l], the paths C I C I C correspond to the singularity of the control component u 1 . On I L I - singular extremals, the time function d l ( t ) vanishes over the whole interval [0, t f ] . This implies that 31 and PZ are zero over [0, t f ] . As P3( t f ) = 0 by the transversality condition, the adjoint vector P(tf) is the zero vector. By the Maximum Principle, there always exists a\n0 These lemmas provide a first reduction within the sufficient family\n1) First of all, we can draw out the types that never end on the line Do. These types are: CC, I C,C, CSC, C I CC, c 1 CbCG I c, and c I C,j2sC when they are not degenerate (i.e., when the length of each portion does not vanish).\nnonzero adjoint vector Q along an optimal path.\n( I ) as follows:\n2) The type C I C I C does not appear.\n3) Thirdly, concerning the types CC I C, C I Csj2SCa/2 I C, CSC,I~ I C, the last two arcs have necessarily the same length to end on the line DO. Hence we only have to consider the types\nAt this stage, we have shown that an optimal path must belong to one of the following three types: C I C,/2SC,j2 I C,j2, CSC,/2 I Cej2, CC, I C, with a 5 ~ / 3 . Now we use simple geometric arguments to reduce again this family.\nIn these cases we can replace the path by a shorter one by extending the piece of straight line on DO up to the final point. We then construct a path C I C,j2S or CS.\nType CC, 1 C, with a 5 ~ / 3 In this case we have the following lemma.\nLemma 3: A portion C,, I Ca. a 5 ~ / 3 : at the end of a path is not optimal.\nProof: Let CO and C1 denote the two tangent circles with radius 1 which support the curve and I the initial point on CO. F the final point on CI and T the point where the two circles are tangent. Then, for a 5 ~ / 3 , we construct the circle C2 with radius 1, passing through F and tangent to CO at P (see Fig. 3). Let 0, be the center of the circle C, and V the line which passes through 00 and bisects the line segment [OI, 0 2 1 perpendicularly. Let M denote the point of V on the arc&: By symmetry the path ,.IT I &. has the same length as the path M P I P>. The line (I. F) is the line DO: while (00, 01) is the line D+ or D-. Then, :;?. This implies that the path Ip I PF is shorter than the path I T F . Therefore we can conclude that a\nU So the type CC, I C, is not optimal and we have the following theorem. Theorem 1: A sufficient family for the free final direction problem is C, I cT/2sd with a < ir /2 and d 2 0, C, I Cb with a < b < x / 2 , c,sd with U 5 a12 and d 2 0.\nCC, I Ca, csc,/2 I Crj2, c I CS/2SC,/Z I C*j2.\nTypes C I CxpSCaj2 I G j 2 and CSC,/Z I C a p\npath with a final portion C, 1 C, is not optimal.\nIv. OPTIMAL PATH SYNTHESIS\nIn this section, we solve the synthesis problem by simple geometric arguments. We give the closed-form expression of the optimal control law that steers the system from (0, 0, 0) to any given position ( x , y ) .\nIf 7 is a path from (0, 0, 0) to (s. y, 8) then there is a path 7, from (0, 0, 0) to ( x , --y. -8) symmetric to (7) with respect to the abscissa axis. In the same way, there is a path IY from (0, 0, 0) to ( - x , y, -8) symmetric to 7 with respect to the ordinate axis. By combining these two symmetries one can build another path, called -7, symmetric to 7 with respect to the origin, from (0, 0, 0) to\nAccording to this remark, if 7 is optimal for the free final direction problem, then one can build three other optimal paths I,, 'TY, and -7 isometric to 1. So our problem has two perpendicular symmetry axes. Therefore, we shall limit our study to the first quadrant.\n( - X . -y, 8 ) ."
+ ]
+ },
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+ "image_filename": "designv11_6_0002222_1.533555-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002222_1.533555-Figure12-1.png",
+ "caption": "Fig. 12 Tooth flank measurement",
+ "texts": [
+ " Once the Path of Contact ~PoC!, e.g., the locus of all contact points on the tooth flank, is obtained, the Bearing Pattern is easily calculated by searching for a given separation between the meshing tooth surfaces along the PoC. A.4 Tooth Surface Measurement and Error Surface. Tooth surface measurement is performed by a Coordinate Measurement Machine, or CMM, using a high precision probing head which, when moved in different directions, detects contact with an obstacle such as a tooth flank ~Fig. 12!. The probe is a small sphere of known radius. The Error Surface is the difference between the theoretical and measured coordinates in the direction of the tooth surface unit normal for each measurement data point. Since measurements correspond to the center of the probe sphere, the measured coordinates are compensated using the following relation: X\u0304comp5X\u0304Meas2R\u2022N\u0304 (A5) where X\u0304comp is the compensated tooth flank coordinate, X\u0304Meas is the measured coordinate, R is the probe sphere radius, and N\u0304 is the tooth flank unit normal vector"
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+ "image_filename": "designv11_6_0003554_13552540510601309-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003554_13552540510601309-Figure10-1.png",
+ "caption": "Figure 10 Equal valued iso-parametric lines of two surface patches on same vertical plane",
+ "texts": [
+ " Further, equal valued isoparametric lines of the two surfaces are contained on the same vertical plane (Figure 9). Last of all, the iso-parametric lines of the ruled patch are all straight lines. A number of such vertical planes separated by small parametric increments are considered across each Bezier surface patch to detect the intersection points. So, the search for intersection between the two surface patches is reduced to a 2D check for intersection between their respective iso-parametric lines in a vertical plane (Figure 10). In order to track down an exact intersection, the horizontal distance between the Bezier iso-parametric and Ruled patch iso-parametric is determined. A flip in the sign of this distance vector indicates the existence of an intersection. The exact Volume deviation in direct slicing Chandan Kumar and A. Roy Choudhury Volume 11 \u00b7 Number 3 \u00b7 2005 \u00b7 174\u2013184 intersection point is located by iterating and reducing the parametric interval within which the intersection is detected. Figure 11(i) shows the CAD model with a locally reconstructed Bezier patch. Few of the intersection points obtained by the above procedure are shown in Figure 11(ii). For calculating the volume deviation (cusp volume), each reconstructed Bezier surface patch is checked for intersection points (Figure 10). If no intersection points are present throughout the Bezier surface patch then cusp volume is given by equation (5). If intersection points were present (as found by the IS algorithm), the Bezier surface has to be apportioned accordingly. First the Bezier surface is separated into strips along one iso-parametric direction. Any one of such strips comprises of two consecutive lines from the set of isoparametric lines used for detecting intersection points in the IS algorithm. Several cases may arise: (1) If the iso-parametric lines constituting the strip do not have any intersection point then the volume deviation (cusp volume) is given by: dv \u00bc jVBP \u00fe VTS \u00fe VRP \u00fe VBSj \u00f06\u00de (2) If the iso-parametric lines constituting the strip have only one intersection point each"
+ ],
+ "surrounding_texts": []
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+ "image_filename": "designv11_6_0001045_a:1019555013391-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001045_a:1019555013391-Figure2-1.png",
+ "caption": "Figure 2. Body i \u2013 forward kinematics.",
+ "texts": [
+ " In our formalism, the reference point for computing the resultant joint force Fi and pure torque Li (for joint i) being chosen as the point Oi (located on the parent body h), the following augmented parameters are also introduced: bi z = m\u0304izi + bi = \u2211 j :i\u2264j mj dij z ; Ki z = Ii \u2212 \u2211 j :i\u2264j mj d\u0303ij z d\u0303ij z (4) defined with respect to point Oi (Figure 1). The kinematic formulation is of course similar to the one used for the classical recursive Newton\u2013Euler scheme. We shall briefly recall these equations for our case. In Figure 2, the various kinematical elements are represented and in the following equations, \u03d5i and \u03c8 i represent unit vectors aligned with joint i axis, respectively for a revolute and a prismatic joint. For body i, one can write: \u2022 Absolute position vector: pi = ph + dhi z , for the attachment point Oi on body h. (5) \u2022 Absolute velocities: \u2013 angular: \u03c9i = \u03c9h + \u03d5i q\u0307i; (6) \u2013 linear: p\u0307i = p\u0307h + \u03c9\u0303h .dhi z + \u03c8hq\u0307h. (7) \u2022 Absolute accelerations: \u2013 angular: \u03c9\u0307i = \u03c9\u0307h + \u03c9\u0303i .\u03d5i q\u0307i + \u03d5i q\u0308i; (8) \u2013 linear: p\u0308i = p\u0308h + (\u02dc\u0307\u03c9h + \u03c9\u0303h "
+ ],
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+ "image_filename": "designv11_6_0003587_1.2125971-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003587_1.2125971-Figure2-1.png",
+ "caption": "Fig. 2 Schematic diagram of the TriVariant",
+ "texts": [
+ " Two are identical UPS limbs and the other is a UP limb whose output link is fixed with the mobile platform. Here, U, P and S represent the universal, prismatic, and spherical joints respectively, and P denotes that the corresponding joint is active. The TriVariant can be considered as a simplified version of the Tricept robot, achieved by integrating one of the three active limbs into the passive one while keeping the required type and degrees of freedom. For simplicity, we use \u201cTricept\u201d and \u201cTriVariant\u201d to refer to the 3-DOF modules in what follows. Figure 2 shows a schematic diagram of the TriVariant, where Bi for i=1, 2, 3 represent the centers of the U joints and Ai for i=1, 2 the centers of the S joints. A3 is the intersection of the axial axis of the UP limb and its normal plane in which Ai i=1, 2 is located. Since limb B3A3 is fixed with the mobile platform, A3 can also be considered as the reference point of the mobile platform. Similar to Tricept 605 9 , it is assumed that the rotation axes of the outer ring of the U-joints of the three limbs are parallel and located in the same plane",
+ " It was reported in 12 that the order of the end polynomial equation of the Tricept is 24, meaning that it may have at most 24 real solutions. Whilst, it is easy to see from Eq. 11 that the order Transactions of the ASME hx?url=/data/journals/jmdedb/27819/ on 03/20/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F of the end polynomial equation of the TriVariant having a general geometry is 8, resulting in at most 8 real solutions though the type and degrees of freedom of two robots are identical. The difference in the number of solutions will be explained in Sec. 5. 3.2 A Special Case. As shown in Fig. 2, if B3\u2212x3y3z3 is placed in such a way that either B3B1 or B3B2 is coincident with the x3 axis, i.e., the rotation axis of the outer ring of the U joint of the UP limb, the position vector of Bi in B3\u2212x3y3z3 becomes bi = bix biy 0 T = bi 0 0 T 13 For simplicity, let i=1, then b1x=b1 and b1y =0, leading to d12 =d13=0. As a result, Eq. 7 for i=1 is simplified as d11 = A1s 3 + B1c 3 + C1 = 0 14 where A1 = 2q3b1, B1 = 2a10xb1, C1 = c1 Thus, 3 can be explicitly obtained by 3 = 2 arctan \u2212 A1 A1 2 + B1 2 \u2212 C1 2 C1 \u2212 B1 15 On this basis, since b2y 0, Eq",
+ " 7 for i=2 becomes A2s 3 + B2c 3 + C2 = 0 16 where A2 = 2b2y a20xs 3 \u2212 q3c 3 , B2 = 2a20yb2y C2 = c2 + 2b2x q3s 3 + a20xc 3 This means that 3 can also be explicitly achieved by 3 = 2 arctan \u2212 A2 A2 2 + B2 2 \u2212 C2 2 C2 \u2212 B2 17 It is easy to see that for this special case the TriVariant may have at most 4 real forward position solutions. Obviously, the same conclusion can be drawn when B3B2 is coincident with the x3 axis. The dimensions of the TriVariant given in 13 is employed for the forward position analysis, with B1B2B3 and A1A2A3 shown in Fig. 2 being equilateral triangles, and the position vectors of Bi in B3\u2212x3y3z3 and Ai in A3\u2212u3v3w3 being given by b1 = 519.62 \u2212 300 0 T b2 = 519.62 300 0 T a10 = 103.92 \u2212 60 0 T a20 = 103.92 60 0 T In order to justify the results of the forward position analysis, the position vector of A3 is arbitrarily chosen within the workspace as follows: r3 = 450 350 850 T 18 This allows a set of limb lengths to be determined by the inverse kinematic analysis as a reference for the forward kinematics. q1 = 1011.69, q2 = 790"
+ ],
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+ "image_filename": "designv11_6_0001980_robot.1995.526028-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001980_robot.1995.526028-Figure4-1.png",
+ "caption": "Figure 4 - A Planar Contact",
+ "texts": [
+ " We utilize Equations (17), (24), and ( 5 ) to get: K, = The eigenvalues of KG are strictly greater than zero, and thus the grasp is stable. 4. Planar Grasps A slight change in notation is required. The frame 0 is again the world reference frame, chosen at an arbitrary location, and a frame oc is again defined (fixed in space) at each contact point. However, both are planar x-y frames, and oc is aligned at each contact such that the y-axis is along the inwardly pointing normal of the grasped object, while the xaxis is parallel to the common tangent (see Figure 4). For a gravitational force, the frame ocg coincides with the center of gravity, and is aligned such that y-axis points in the same direction as the gravitational force. The curvature of the grasped object (the signed inverse of the radius of curvature at the point of contact, positive for convex surfaces) is denoted by KB, while the curvature of the fingedfixed surface is given by KA. Finally, the tangential force at equilibrium is denoted as Fto. If we let the force vector F = [F,,, F,, MIT, and let x be the position vector given by x = [x, y , BIT, we get: KG is again given by Equation ( 5 ) where we redefine (.)T as follows: let (dx, dy) be the coordinates of the frame 0 as seen from (.)oc, and let CP be the relative angle of rotation of 0 from the frame (hc (see Figure 4). (.IT is given by: AFIO = KG Axlo (25) cos@ -sin@ = [si;@ co; @ -!x J (26) We define FX and & as: i K ~ is still given by Equation (24), while we can use the spatial results to define Kc as: - 1370 - 1 K, and FX above are written for a frictional contact. If the contact is frictionless, k, and F, should be set equal to zero. 4.1. Example 2 Consider the enveloping grasp of a slippery elliptical object, as shown in Figure 5. Since the coefficient of friction is very low, the contacts are modeled (conservatively) as frictionless"
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+ "image_filename": "designv11_6_0001930_5326.923273-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001930_5326.923273-Figure2-1.png",
+ "caption": "Fig. 2. Inverted pendulum system.",
+ "texts": [
+ "8) for the region nm 2 0, where Gnm a G nm nm 0 T 0 ; Gnm a Gnm nm 0 T 0 Pa P 0 0 T 0 and Qnm ai = Qnm i Rnm i Rnm T i snmi (i = 1; 2): Proof: By definition, it is clear that the Lyapunov function candidate represented by (27) is continuous, piecewise differentiable, positive definite and descresent so that there exist > 0 and > 0 such that kx(t)k2 V (t) kx(t)k2: (29) The time derivative of V (x) is given as follows: dV dt = _xTa P nm a xa + xTa P nm a _xa + xTa _P nm a xa = Cof(G nm x + nm )TPnmx + xTP nm(Gnm x+ nm ) (Gnm x+ nm )TP nmx + xTP nm(Gnm x+ nm )g: a.e. By following the procedure of Proposition 1 and Corollary 1 with the exception that P is replaced with P nm dV dt < 0 a.e. Then, by the nonautonomous Lyapunov theory [34], the closed-loop fuzzy system is asymptotically stable. IV. EXAMPLE In this section, an illustrative example is provided to demonstrate the validity of the suggested stability analysis method. The plant to be controlled is an inverted pendulum with two states x = (x1 x2) T = ( _ T ) as in Fig. 2. The task here is to design and analyze an FLC that balances the pendulum. Its dynamics are nonlinear and is represented by the Takagi\u2013Sugeno fuzzy model as follows [11]: R1: If x1 is about 0; then _x = A1x+B1u: R2: If x1 is about =4; then _x = A2x+B2u: and other parameters are as follows. The mass of the cart M is 8.0 kg, the mass of the pole m is 2.0 kg, the distance of the center of mass m from the cart is 0.5 m, the gravitational constant g is 9.8 m/s2, and a = 1=(m+M). The FLC fedback by the position ( ) and its derivative is designed by human beings"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003354_1.2101857-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003354_1.2101857-Figure1-1.png",
+ "caption": "Fig. 1 Schematic of brush seal",
+ "texts": [
+ " Findings also indicate that variations in front plate geometry do not directly affect leakage performance. A long front plate or damper shim considerably changes the flow field while at the same time having limited effect on the pressure field. Moreover, a strong suction towards the clearance enhances inward radial flow in clearance operation. DOI: 10.1115/1.2101857 Developments in brush seal design have demonstrated the significance of the flow field dictating seal dynamics and performance. As illustrated in Fig. 1, early designs utilized short front plate configuration. Welded at the outer periphery, front and backing plates clamp the bristle pack. The straight backing plate is extended to provide mechanical support for tiny bristles. This geometry is referred to as the standard or conventional brush seal. The bristle pack is divided radially into two distinct regions, which are labeled the fence height and upper regions Fig. 1 . The fence height is the radial height between bristle tips and backing plate inner diameter. The upper region, on the other hand, is the rest of the bristle height out to the bristle pinch point. The aim of brush seal evolution and continued efforts at development have been to raise brush seal performance, benefits, and usage. A review of the literature reveals that most of the improvements and disclosures to date have focused on the geometry of front and backing plates. The number of issued patents dealing with brush seal geometry is considerably high",
+ " After an extensive effort at calibration, radial pressure on the backing plate, axial pressure on the rotor, and leakage are all compared well with experimental data and other porous medium analyses. Details of the calibration data will be discussed in the results and discussion section. 2.1 Front Plate Configurations. In order to cover common concepts while keeping the number of analyses manageable, five different front plate configurations, as illustrated in Fig. 2, have been selected. The standard seal geometry, which is referred to as case 1, has a short front plate and straight backing plate, as given by Bayley and Long 20 and Turner et al. 21 Fig. 1 . This configuration is set as the baseline. The model uses a bristle pack thickness of 0.75 mm 0.0295 in. . The thickness of the front and backing plates is 1.6 mm 0.0630 in. . The fence height is set at 1.4 mm 0.0551 in. with a free bristle height of 10.68 mm 0.4205 in. . In the second configuration, a long front plate in contact with the bristle pack is employed. In terms of flow formation, this case represents a damper shim application. Case 3 is a typical long front plate configuration with a relief"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002583_ias.2000.880991-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002583_ias.2000.880991-Figure6-1.png",
+ "caption": "Fig. 6. Fully pitched winding SRM",
+ "texts": [
+ " Therefore torque can be derived using: teeth Combining the above equations gives: Therefore, once the tooth flux/MMF/position characteristics are known (whether by FE or measurement) a corresponding torquelcurrentlposition characteristic can be determined. This may then be used to determine the instantaneous running torque. The torque per tooth, derived from the flux1MMF curves of fig. 4 (a), is shown in fig. 5. 111. DETAILED SIMULATION RESULTS The simulation method has been implemented and extensively validated through comparison with measurements, made upon an SRM with three phase fully pitched windings (see fig. 6). Details of this machine are given in the appendix. All results presented here use an asymmetric half bridge converter for each phase supply. The per tooth flux/MMF/position characteristics have been derived by measurement and the results embedded as a lookup table in the simulation software. Comparisons with measurement will be presented in section IV, but it is first worth looking at detailed simulation results, which help explain operation of the machine. The parameters shown in figs. 7 to 9 are in the order that they are calculated in the simulation, as shown in the flow chart of fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003764_bf02953383-Figure19-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003764_bf02953383-Figure19-1.png",
+ "caption": "Fig. 19 Negative casting mold for radial bearing pad.",
+ "texts": [
+ " The test showed that there was no instability in the axial direction, since the mass was well below me, but that tilt vibrations would commence as soon as the diametral 88 R. Snoeys and F. AI-Bender 5.2 Non-Deformable Bearing Surfaces Bearing pads with a non-deformable wall may be manufactured with a similar casting technique as indicated in Fig.l8; however, the casting has to be carried out now with respect to an appropriate negative shape. This casting model for a radial bearing pad may by obtained as illus trated in Fig.19. The molding cylinder is provided with a membrane. Cylinder and membrane are accurately machined at the nominal diameter of the bearing pad. The membrane may be deflected radially corresponding to the desired amount of the convergency of the gap. The same technique can be used for axial bearing pads, the bearing pad itself may also be made directly by diamond-tool turning on a precision lathe. 6. CONCLUSIONS (1) A significantly larger carrying capacity may be obtained by using convergent gap shapes"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000403_s0924-0136(98)00412-9-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000403_s0924-0136(98)00412-9-Figure3-1.png",
+ "caption": "Fig. 3. A schematic rendering of three candidate deposition path cross-sections: (a) raster path; (b) profile path; and (c) spiral path.",
+ "texts": [
+ " dimensions of motion (X,Y interpolation and a Z incremental motion) this shape was a good demonstration of the technology because it demonstrated the deposition of a shape that would be difficult or impossible to fabricate using conventional methods. 2.3. Fabrication procedure A substrate plate was fixtured horizontally and the DLF deposition head positioned vertically aligning the focal point of the laser and powder at the surface of the plate. The model allowed a variety of tool paths to be evaluated by simply making changes to the model parameters and regenerating new deposition paths. Geometric renderings of candidate tool paths are shown schematically in Fig. 3. To maintain a consistent build up from one layer to the next, yet achieving full fusion of the deposit from one layer to the next, the system parameters, such as laser power, had to be chosen as a function of the deposition path parameters. The laser head orientation was held constant vertically (normal to the deposited surface). System parameters were automatically sequenced as a function of system commands embedded within the tool path. The numerical control file was loaded into the system controller and run in open loop using the parameter set given in Table 3",
+ " The DLF process is characterized by a much more complicated set of processing conditions that require precise control to achieve an acceptable end product. Presently limited to open loop control, a parameter study is often required when changing materials, or specific geometry. Various candidate deposition path types were evaluated and analyzed. The track width, step-over distance and fill path algorithm were the main parameters considered. The three basic path types first evaluated are shown in Fig. 3. Fig. 3a shows a Type 1 path in which a raster motion is used to traverse the areas to be deposited in a series of connected linear parallel motions. A larger number of short starts and stops are seen along with a number of retractions and traversal movements, shown as dotted lines in Fig. 3a. Associated with the many starts and stops are a number of acceleration/deceleration movements, the cumulative effect of which resulted in an unwanted build-up of fused material, particularly in the narrow wall sections. Retraction and traversal movements connecting the disjointed deposition sections are seen to cross open areas where no deposit was desired, thus requiring a laser shutter closing. The time constants associated with acceleration/deceleration and beam shuttering disturbed the deposition consistency at normal process speeds. Smooth fully fused layers of the deposit were not achievable using the raster deposition path type. Fig. 3 b shows multiple perimeter paths that may be used to ensure a sharp well defined edge along the wall of the deposited part. Fig. 3 c shows a Type Spiral tool path characterized by many fewer starts, stops and traverse motions. More time is spent depositing material and less time spent in traverse moves, acceleration and deceleration. More locations within the area to be spiral deposited suffered from a variation in deposition path spacing as shown in Fig. 3 c than with the Type 1 raster path shown in Fig. 3 a. Faster, smoother deposition was realized with the spiral path, although small unfused regions were observed in the locations corresponding to variations in the step over distance. Table 3 provides the laser parameters used. Fig. 4 a\u2013d show an optimization of the spiral tool path achieved through a selection of a smaller \u2018tool\u2019 size parameter. Fig. 4 a and b show a section of a spiral tool path and the corresponding location in a part cross-section deposited using this path, respectively. A small amount of porosity resulting from insufficient fusing of one trace into the next was seen at the locations of wider deposition path spacing"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001045_a:1019555013391-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001045_a:1019555013391-Figure8-1.png",
+ "caption": "Figure 8. Simple two-dimensional human body model.",
+ "texts": [
+ " This problem can be circumvented by moving the reaction forces an torques measurement point. Obviously, the best place would be the trunk since this leads to the minimum length kinematic chain. The idea would be to rigidify the trunk by some lightweight equipment, and to connect this equipment to a force measuring platform. In this case, the maximum number of dof in the kinematic chain reduces to six which is quite better according to Figure 7. In order to compare the results we can expect from both techniques, we have applied them to a rather simple model of the human body (Figure 8), consisting of six bodies interconnected by revolute joints. This model has been used to analyze a recorded movement of block in volleyball. The dynamical parameters will be identified using both techniques and compared to the exact values of the model. Based on the recorded block movement, we will then compare the calculated joint torques based on the two sets of identified parameters to the actual ones. The identification trajectory is composed of six different movements in which each limb is successively moved"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002082_s1350-4533(01)00125-4-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002082_s1350-4533(01)00125-4-Figure1-1.png",
+ "caption": "Fig. 1. Model of the human body, consisting of six segments. All segments were considered to be solid links with constant masses, lengths, and moments of inertia. X1, Y1, Z1 represents the global coordinate system with origin O at ground level. The X-axis is oriented vertically. The Y-axis is in the plane of progression of gait. The Z-axis is orthogonal to the plane of XY. FX and FY represent the tripping forces.",
+ "texts": [
+ " Furthermore, models with one, two, or three links were developed to predict the impact velocity and force of falls to the side from a standing position [30,31]. However, there have been no reports on the application of dynamic simulation during gait to falling. The purpose of this study was to develop an analytical model to simulate and visualize the motion of a body during a muscle relaxed fall after tripping on an obstacle during gait. The human body was modeled as a set of six articulated, rigid segments with revolute joints (Fig. 1). The swing phase of gait was modeled as an open chain linkage with one end of the system (i.e. the stance ankle) fixed to the floor and the other end (i.e. the swing ankle) in space. The segments consisted of the stance foot, shank, and thigh, HAT (head, arms and torso), and the swing thigh and shank. The joints consisted of the stance ankle, knee, and hip joints, and the swing hip and knee joints. The stance ankle was modeled as a three degrees of freedom (dof) joint, the stance and swing knees as single dof joints (flexion\u2013extension) and the stance and swing hips as three dof joints"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000732_s0301-679x(98)00043-7-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000732_s0301-679x(98)00043-7-Figure2-1.png",
+ "caption": "Fig. 2 Detailed drawing of the conical bearing",
+ "texts": [
+ " Therefore, water pressure is increased at the outlet of the feeding holes due to the centrifugal force under rotation and water in the bearing clearance is pumped up by the viscous effect of spiral grooves. This raises water pressure in the bearing clearance and the proposed bearing can have large load capacity and excellent stability at high speeds. Table 1 shows the principal dimensions of the proposed bearing. These values are used in theoretical calculations and the experiment mentioned below. Fig 2 shows the coordinate system of the conical bearing treated in this paper. In numerical calculations, water flow in the bearing clearance is assumed to be laminar, viscous and isothermal. In the calculation of pressure distribution for the groove\u2013ridge region, the narrow groove theory by Vohr6 is adopted. The mass flow rates for unit width in the s and u directions in the bearing clearance, h, are given as follows, considering the centrifugal force qs 5 2 rh3 12m \u2202p \u2202s 1 h3 12m \u00b7 3 10 rs sin2g\u00b7v2 (1) qu 5 2 rh3 12m \u2202p r\u2202u 1 rs sing\u00b7vh 2 The overall pressure derivatives \u2202p\u0304 \u2202s , \u2202p\u0304 r\u2202u are expressed by using the local groove and ridge derivatives \u2202pr \u2202s , \u2202pr r\u2202u , \u2202pg \u2202s and \u2202pg r\u2202u Tribology International Volume 31 Number 6 1998 333 \u2202p\u0304 \u2202s 5 a \u2202pg \u2202s 1 (1 2 a) \u2202pr \u2202s , \u2202p\u0304 r\u2202u 5 a \u2202pg r\u2202u 1 (1 2 a) \u2202pr r\u2202u (2) where a is a fraction of the width of the ridge\u2013groove pair that is occupied by the groove"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000980_9.310037-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000980_9.310037-Figure6-1.png",
+ "caption": "Fig. 6. plane (right). The partition of the first quadrant (left) induces the partition of the",
+ "texts": [
+ " There are four types in the family C,sd. and each of them leads to points lying in a different quadrant. So any additional refinement is unnecessary. D. Partition of the First Quadrant From the sufficient family given in Theorem 1 and the refinement above the partition of the first quadrant is completely built. The three domains of this partition correspond to the paths: l,l:,,s,j with n < ir /2 and d 2 0, 0 l;l$ with a < c < n/2. . l tsf with b 5 i r /2 and d 2 0. The outline of the different domains appears easily (see Fig. 6). The boundary between the domain of points reachable by a path Its+ and the domain of points reachable by a path l ~ Z ~ T l z ) s ~ is obtained when a = 0, b = 7 ~ 1 2 . It is the upper vertical half-line from the point (1, 1). The boundary between the domain of the type l ~ l ~ ~ , s ~ and the domain of the type 1,l: is obtained for n = b , P = 7712. and d = 0. It is an arc of the circle centered at Oo(0. -1) and with radius 6. Between the domain of the type 1;l: and the domain of the type Its:, the boundary is obtained for a = 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003382_s11340-006-9257-4-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003382_s11340-006-9257-4-Figure12-1.png",
+ "caption": "Fig. 12. Rotation and slide motion of a rigid ball during an oblique impact with a target",
+ "texts": [
+ " The increasing rates of % and q tended to decrease slightly as vi increased. The average tangential velocity vt and angular velocity w were determined by dividing % and q by the contact time tc. The results are plotted in Fig. 11. There was some scattering of the data; however, vt and w increased almost linearly with vi: vt = 3.1, 10.3, and 20.1 m/s while w = 1,297, 3,851, and 9,216 rpm for vi = 10, 29, and 60 m/s, respectively. Note that the values of vt were about 30% of vi. Rigid Body Model The rigid body model illustrated in Fig. 12 was used to study the dynamic contact behavior. Here, the target was stationary and inclined at an angle qi to the vertical, and a ball of mass m and radius r plunged into the target horizontally with an inbound ball velocity vi. The following assumptions were made. First, the ball and target were perfectly rigid. Second, F = 2R, where F is a frictional force between the ball and target, 2 is the coefficient of sliding friction, and R is a reactive force perpendicular to the target surface. Third, the tangential ball velocity vt was gradually reduced due to F, while the angular velocity 5 was gradually increased"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000299_301-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000299_301-Figure8-1.png",
+ "caption": "Figure 8 . Figure 9. Figure 10.",
+ "texts": [
+ " EQUIVALENCE O F A C U R R E N T C I R C U I T A N D A M A G N E T I C S H E L L I N ALL M E D I A The confusion mentioned in 5 1 may now be discussed. This arises through forgetting that the forces due to magnets or current circuits immersed in a polarizable medium depend on the shape of the cavity in which they are placed, and further, that a current circuit can be put in two different cavities whereas a magnetic shell cannot. The current circuit can be put in the medium either by removing a cylindrical channel to take just the wire itself (figure 8) or by inserting it as a whole in a disc-shaped cavity (figure 9). The latter cavity is suitable for the equivalent magnetic shell (figure 10) whereas the former is not. I t is easy to see that as long as we treat the circuit T o see this clearly, consider figures 8,9 and 10. 40-2 and magnetic shell in a similar manner they will be equivalent in the medium just as they are in a vacuum. Consider the Internal Magnetic Force at any point P in each case : in figure 8 there is no surface distribution of free pole, so that F , = 0. Hence H = H A and the field is the same as in vacuo. In figures 9 and 10 a surface distribution of 596 pole of amount I appears, equivalent to a row of doublets acting in the opposite direction to the fields of the current and the shell. This produces a force Fl at P, so that we have now H = HA - Fl. We can easily show that this becomes H A / p . Let 4 be the strength of the shell, i.e. the magnetic pole per unit surface, I is the magnetic pole per unit surface of the cavity, so that at P the potential, which is !2 = wC in a vacuum (where w is the solid angle subtended by the shell or circuit at P), becomes i2 = w(+ -I) in the medium = U# (/A - 4myp = ** P Thus the potential, and consequently the force, is reduced in the ratio /A : 1. This clearly applies also to the current circuit in figure 9. The difference between the cases illustrated in figure 8 and figure 10 has led many authors of well-known text-books to be at pains to explain that a current circuit and a magnetic shell which are equivalent in air are no longer so in a medium of permeability p. In fact, it is maintained that the magnetic shell of strength i in air must be of strength pi in the medium. We have seen, however, that a current circuit and a magnetic shell which are equivalent in a vacuum are equivalent in any medium provided that they occupy similar cavities. The force A new treatment of electric and magnetic induction 597 they produce is, in each case, diminished in the'ratio p : 1. A current circuit in which the wire is entirely surrounded by a medium, as is normally the case in gases and liquids, exerts the same magnetic force as in a vacuum. If we consider the force on a current element at P, i.e. the force in a disc-shaped cavity whose axis is parallel to the magnetization, we find : figure 8. B = p H and H = HA4 ; :. B =pH,, or p times as great as in a vacuum. figures 9 and 10. B =pH and H = Ha4/p ; :. B= H,, or the same as in a vacuum. Thus when a current circuit is entirely surrounded by the medium, as in figure 8, the Internal Magnetic Force is unaltered but the Internal Electromagnetic Force or Induction is p times as great. If the circuit is in a cavity as in figure 9, the Internal Electromagnetic Force is unaltered and the Internal Magnetic Force is p times less. No difference arises, however, in the cases illustrated in figures 9 and 10, whether we consider the respective magnetic or the electromagnetic forces. We can conclude therefore that a current circuit and a magnetic shell are wholly equivalent in all media, provided they occupy similar cavities",
+ " In these cases it will be necessary to consider as well the effect of cavities in which the measurements are made, since the assumptions made in choosing our rod-shaped and disc-shaped cavities (suitable only for point-poles) will not in general hold ; the direction and intensity of the magnetization may not, for instance, be constant over the region occupied by the cavity. Such cases will therefore require special treatment. One case of importance can be dealt with : that of the current balance which is used for defining the unit of current. Here the current coils are situated as in figure 8, i.e. surrounded entirely by air or partly by other materials such as marble. The force between the coils is therefore greater than would be the case in a vacuum. The very small value of the permeability of air makes a correction unnecessary. 5 15. T H E FIVE ELECTROMAGNETIC RELATIONS We can now re-state in rather more precise form than usual the five electro- magnetic relations : (1) The magnetic potential at a point produced by a current flowing in a closed linear conductor is equal to the strength of the current i multiplied by the G"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003288_j.conengprac.2004.04.023-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003288_j.conengprac.2004.04.023-Figure2-1.png",
+ "caption": "Fig. 2. Airframe axes.",
+ "texts": [
+ " Typically, if the system is persistently exciting, then all the parameters will converge to their true values. The missile model used in this study derives from a nonlinear model produced by Horton of Matra-British Aerospace (Horton, 1992). This study will look at the reduced problem of a 2 DOF controller for the pitch and yaw planes without roll coupling. The angular and translational equations of motion of the missile airframe are given by \u2019r \u00bc 1 2 I 1yz rV0Sd 1 2 dCnrr \u00fe Cnvv \u00fe V0Cnzz ; \u2019v \u00bc 1 2m rV0S\u00f0Cyvv \u00fe V0Cyzz\u00de Ur; \u00f02\u00de where the variables are defined in Fig. 2 and Tables 1 and 2. Eqs. (2) describe the dynamics of the body rates and velocities under the influence of external forces (e.g. Cyv) and moments (e.g. Cnr), acting on the frame. These forces and moments are derived from wind tunnel measurements and by using polynomial approximation algorithms, Cyv;Cyz;Cnr;Cnv and Cnz (Horton, 1992) can be represented by polynomials which can be fitted to the set of curves taken from look-up tables for different flight conditions. A detailed description of the model can be found in Horton (1992)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002746_0278364905060149-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure4-1.png",
+ "caption": "Fig. 4. Installation examples of displacement sensors in universal joint and revolute joint.",
+ "texts": [
+ " For the variables gBi and gSi , the direction in which each anvil of the sensor\u2019s head is pushed is decided to be positive. A master ball used in each joint must have proper sphericity to be a reference surface for the runout measurement. In addition, the sensor head\u2019s anvil must preferably be a plane because it is in contact with the spherical surface of the master ball. at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from The master ball can be installed in a universal joint, as shown in Figure 4(a), and in a revolute joint, as shown in Figure 4(b). In any case, the sensor can measure both the elastic deformation and the runout of the spherical joint to compensate for the limb\u2019s length change. In particular, because it is considerably difficult to manufacture joints with both high stiffness and high rotational accuracy, this compensation method is noticeably useful. In an extreme case, the sensor measures any joint play in the limb direction. Generally, some materials with low thermal expansivity, such as Super-Invar (expansivity: 0.3\u20130",
+ "2, respectively, were adopted in an experimental CMM (Oiwa 1997, 2000) shown in Figure 8. This CMM uses the three-degrees-of-freedom parallel manipulator shown in Figure 2(b). The sectional view of an extensible limb is shown in Figure 9 in detail. Using the same method as that shown in Figure 3, an electrical comparator (Mahr 1202IC+1304K) is installed in the spherical joints connecting the limbs with the machine frame. Two electrical comparators are also used to measure the errors of the revolute joint as shown in Figure 4(b). Moreover, Super-Invar rods connect a scale unit (Sony BS75, with measuring length at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from 220 mm and resolution 50 nm) with the spherical joint and the revolute joint, respectively, to eliminate the influence of the limb\u2019s thermal and elastic deformations according to the same method as that shown in Figure 5. The scale unit and the linear scale mounted on Super-Invar plates are guided by using a simple notch type linear spring to allow them to move in the longitudinal direction"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002746_0278364905060149-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure1-1.png",
+ "caption": "Fig. 1. Various causes of relative positioning error between tool and workpiece for conventional machines.",
+ "texts": [
+ "1177/0278364905060149 \u00a92005 Sage Publications KEY WORDS\u2014parallel kinematics machine, error compensation, joint runout, joint deformation, frame deformation, thermal expansion, machine tool, coordinate measuring machine When improvement of machining accuracy and measurement accuracy is required, it is extremely important to accurately obtain the relative position between the tool and the workpiece of the machine tool or the coordinate measuring machine (CMM). In an actual machine, however, internal and external disturbances (shown in Figure 1) noticeably cause positioning errors. Thus, not only moving accuracy but also structural and thermal stability in the whole machine are strongly required for achievement of precision. In general, much improvement in guide element accuracy and structural stiffness has been achieved to decrease the motion error and the elastic deformation caused by external and internal forces (e.g., Ramesh, Mannan, and Poo 2000a; Lee et al. 2004). However, increased mass along with such improvements has caused further motion error and elastic deformation due to increased inertial force and frictional force"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000540_0094-114x(95)00106-9-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000540_0094-114x(95)00106-9-Figure1-1.png",
+ "caption": "Fig. 1. The Stewart platform.",
+ "texts": [
+ " Unlike the convention of developing a set of kinematic equations and then solving them, an alternative approach is proposed which involves just a search and verification purely from geometric considerations. An attempt at conceptual construction of the mechanism under given constraints results in the prediction of tentative solutions, which are subsequently corrected. The algorithm is implemented and two case studies are reported. The proposed algorithm is simple to implement, finds all the real closures and is applicable to the most general case of the Stewart platform. Copyright \u00a9 1996 Elsevier Science Ltd I. I N T R O D U C T I O N The Stewart platform (Fig. 1), a generalization of a mechanism originally proposed by Stewart [l] as a flight simulator, is the most famous parallel manipulator having two bodies connected by six extensible legs with spherical joints at both ends (or spherical joint at one end and universal joint at the other). One of the bodies is fixed to the frame and forms the base, while the other, known as the platform acts as the end-effector. The leg extensions are the six inputs which can provide an arbitrary position and orientation (6-DOF) to the platform within its workspace"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001980_robot.1995.526028-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001980_robot.1995.526028-Figure6-1.png",
+ "caption": "Figure 6 - A Force Closed, Frictionless Grasp",
+ "texts": [
+ " If the intrinsic stiffness matrix is unstable (contains a negative eigenvalue), the grasp stiffness matrix will also be unstable; however, a intrinsic stiffness matrix which is stable (positive definite) does not necessarily imply that the grasp stiffness matrix will also be stable. Nguyen [13] showed that force closed grasp can be made stable essentially by proving that (his version of) the intrinsic stiffness matrix is positive definite. However, the intrinsic stiffness matrix excludes the compliance of the finger joints. Thus, when the entire system is analyzed, it is possible for a force closed grasp to be unstable. idyTi~jKc~~jT + 5 ITT 'K, 'T + cgTT KcgcgT (29) 5.1. Example :3 Consider thle grasp shown in Figure 6, where each of the contacts is frictionless. This is a force closed grasp. We choose the reference frame, 0, coincident with the contact frame ',Ioc. Thus the transformation matrix IsrT is the identity matrix, and the other transformation matrices are given by: The contact stiffness matrix, K,, the Jacobian, Jg, the joint stiffness, K+ and E are the same for all contacts. We have: 0 - 1371 - while k, = 10000 N/cm. In order to insure equilibrium, we have the following two conditions: As written, the grasp stiffness matrix, KG, is a function of both the applied force, \u2019,IF, and the joint stiffness, K,. For relatively stiff joints applying a small force (a low ratio of I\u2019a\u2019FI to K ) this grasp is stable. However as we increase the the grasp becomes progressively less stable. With the values of applied force and joint stiffness given in Figure 6, an easy calculation using the method in this paper shows: 3JF = L J F and 2 4 7 =4,4F = 1,521 ratio of II, ;P FI to K9 (a weaker spring applying a greater force) I 20000 0 95394 0 20000 -15906 842 -368 3787 95394 -15906 485676 -9.9 842 %=[:;.: 198 -3681 The eigenvalues of KO are positive, as expected since the grasp is force closed. But, the eigenvalues of KG are (-16.8, 4009, 190}, and thus the grasp is unstable. 6. Discussion In this paper, we extend the results of Cutkosky and Kao [3] by including curvature in determining the compliance of a grasp"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003257_tro.2005.844679-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003257_tro.2005.844679-Figure4-1.png",
+ "caption": "Fig. 4. Test for full constraint of this planar cable robot: Does the line segment from P to Q lie completely within the two reversed triangles? (For this case: Yes).",
+ "texts": [
+ " Planar Antipodal Cable Theorem: A planar cable robot with two pairs of cableswith coincident attachment pointsP andQ is force closed if, and only if, the line from P to Q lies completely in the two open force triangles defined by the reversed forces of the two cable pairs. Proof: The set of forces the planar cable robot with the above properties can apply to the moving platform is identical to the set of forces that the two-finger planar friction grasp with fingers from the inside in the aboveCorollary can exert on the object to be grasped. Thus, the same geometric criterion applies for force closure in both systems. Example 1: Force closure can easily be checked for the two-pair planar cable robot in Fig. 3(a) as shown in Fig. 4, by extending the lines of the cables and checking whether the line segment from P toQ lies completely within the two reversed open-ended triangles. This geometric criterion may be useful for the synthesis of planar cable robots. More importantly, it is an example of a tool from grasping that carries over to cable robots. Example 2: Shown on the left in Fig. 5 is a cable robot with cable pairs originating from the same point, i.e., the axes of their motors coincide. The corresponding criterion is demonstrated on the right in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.18-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.18-1.png",
+ "caption": "Figure 2.18. Crossed helical gears and their velocity components.",
+ "texts": [
+ "In par ticular, when the shafts intersect in a right angle, 8 + \u00a2 = n/2 and (2.84) becomes 0 < 8tSPSsin f/\u00abF . With this substitution, the integral is readily evaluated and the energy per unit area is found: W~f!5U~f!tB5W08S sin2f1 V VS8 sin f D , ~15! W085W0 S 11 \u00abF \u00abA 2tA tF D S 11 \u00abA \u00abF tS 2tA D S 11 \u00abF \u00abA 2tA tB 1 2tS tB D >W0S 11 \u00abA \u00abF tS 2tA D , VS85VSS 11 \u00abA \u00abF tS 2tA D . The above approximation for W08 applies when 2tS /tB!1, this inequality is satisfied in the stiffened director structure limit studied here. Now consider the twist regions, in which the energy density is the sum of elastic and electrostatic contributions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003940_1.2338060-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003940_1.2338060-Figure2-1.png",
+ "caption": "Fig. 2 Flexible helicopter",
+ "texts": [],
+ "surrounding_texts": [
+ "om: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/201 this paper, the use of mean axes not only makes matters more complicated but in some cases it can render the formulation at odds with the physical reality. Whatever advantages or disadvantages accrue from the use of mean axes, the procedures used in 4,5 are essentially correct. Unfortunately, the same cannot be said about the subsequent investigations, as at some later time the concept of mean axes was invoked but not really used. Indeed, some later investigators latched onto the notion of mean axes to drop most inertial coupling terms from the equations of motion while failing to enforce the constraints embodied by Eqs. 3 . In fact, some of the investigators did not even give the definition of the mean axes. Typical of investigators regarding the mean axes, Eqs. 3 , as a vehicle to drop the coupling terms with impunity are Nydick and Friedmann 6 and Friedmann, McNamara, Thuruthimattam and Nydick 7 , where the first is a conference presentation and the second is basically a journal version of the first. Indeed, professing to use the mean axes, when in fact they did not, as well as invoking a variety of other assumptions, and confining themselves to the case of steady level cruise, they obtained the greatly simplified equations of motion m V\u03070x + qV0z = X \u2212 mg sin , m V\u03070z \u2212 qV0x = Z + mg cos , jyy 0 q\u0307 = M Mg\u0308 + Cg\u0307 + Kg \u2212 D T\u0303T\u0303 dD = D r\u0303T\u0303T\u0303 dD + Q\u0302 4 in which m is the total aircraft mass, V0x the forward velocity, V0z the plunge velocity, q the pitch velocity, the pitch angle, jyy 0 the mass moment of inertia about the pitch axis y, assumed to be constant, X, Z, and M are associated forces and moment, including those due to aerodynamics, Mg, Cg, and Kg are \u201cgeneralized\u201d mass, damping and stiffness matrices, respectively, is a vector of generalized elastic coordinates, a \u201cmodal\u201d matrix, \u0303 a skew symmetric matrix derived from the angular velocity vector = 0 q 0 T and Q\u0302 a generalized force density vector. Equations 4 are even simpler than they may seem, and we note that the first three are scalar equations and the fourth is a vector equation, as they can be solved independently for the rigid-body translations, rigid-body rotion, and elastic displacements. Indeed, first the third of Eqs. 4 can be solved for the pitch velocity q, and hence for the pitch angle , then the first and second can be solved for V0x and V0z and finally the fourth can be solved for . However, there are several problems with this proposition. In the first place, although the authors do list the definition of the mean axes, Eqs. 3 , they make no attempt to enforce the constraints imposed by them, which can have disturbing implications. Moreover, there is no indication that the aerodynamic forces were ever expressed in terms of mean axes components, nor is there any hint that the aerodynamic forces keep the equations coupled, thus preventing independent solutions of the equations for the rigid body translations, rigid body rotations and elastic deformations. It is clear from 6,7 that the objective is an aeroelasticity analysis, which calls for very simple equations of motion. Yet, the papers begin with a formulation capable of describing the dynamics and control of maneuvering flexible aircraft 8,9 , a very complex problem, and proceed to strip away the elaborate formulation reducing it to Eqs. 4 . In the process of reducing the equations of motion in terms of quasi-coordinates, the authors of 6,7 get tripped by the misuse of mean axes. It appears that the authors of 6,7 would have been better served by beginning directly with aeroelasticity equations rather than with the complex formulation of Ref. 8 . To indicate where 6,7 , went wrong and to highlight some possible negative implication of the use of mean axes, the correct use of the mean axes is discussed later in this paper. Transactions of the ASME 6 Terms of Use: http://www.asme.org/about-asme/terms-of-use n t a a f t h i o t b t r m h u t m b a w v e f r c q e s w t f e t t t a t a d 2 S p s c d t m w a d u t b m b b v s c q J Downloaded Fr The use, and sometimes abuse, of the concept of mean axes is ot confined to missiles, spacecraft, and aircraft. Indeed, abuse of he concept can be found in the case of helicopters as well. From dynamicist\u2019s point of view, helicopters can be regarded broadly s consisting of three parts, the main rotor, the tail rotor and the uselage, all acting together as a single dynamical system. Of hese, the main rotor is by far the most critical part, although a elicopter could not function properly without a tail rotor. Indeed, n the absence of a tail rotor to counteract the angular momentum f the main rotor, the fuselage would spin in a sense opposite to hat of the main rotor. The equations of motion for helicopters can e derived by modifying the approach used for aircraft, modificaions made necessary by the fact that helicopters possess spinning otors. However, this is not the approach used by Cribbs, Friedann and Chiu 10 , who consider the problem of a \u201ccoupled elicopter rotor/flexible fuselage aeroelasticity model\u201d in a very northodox way as far as dynamics is concerned. In particular, hey concentrated on the fuselage alone and invoked the use of ean axes to derive decoupled equations for the fuselage rigidody translations, rigid-body rotations and elastic deformations, s follows: mfx\u0308cm = F, Jf\u0307 + \u0303Jf = Mcm, Mq\u0308e + Kqe = Q 5 here mf is the total mass of the fuselage, xcm the displacement ector of the fuselage mass center, F the resultant vector of all xternal forces acting on the fuselage, Jf the inertia matrix of the uselage, the angular velocity vector of the fuselage, Mcm the esultant vector of all external moments about the fuselage mass enter, M and K are mass and stiffness matrices for the fuselage, e is a vector of generalized coordinates and Q a vector of genralized forces for the fuselage. Equations 5 are very strange in everal respects. In the first place, they are for the fuselage alone, hile insisting that the main rotor was coupled to the fuselage. To his end, they referred to some \u201cequations of equilibrium\u201d derived or the main rotor in a NASA CR dated 22 years earlier, without xplaining how equations of equilibrium derived separately for he main rotor, equations not even given in Ref. 10 , are coupled o equations of motion derived for the fuselage alone. Moreover, he tail rotor is not even mentioned. Finally, it is clear that Eqs. 5 re for a fictitious fuselage at best, as they were derived invoking he use of mean axes, when in fact the mean axes were not used at ll. Later in this paper, it is shown how the problem of helicopter ynamics is to be approached. Proper Formulation for the Dynamics of Aerospace tructures As discussed in the preceding section, the mean axes have been ortrayed as a useful tool in the treatment of such diverse aeropace structures as missiles, spacecraft, aircraft, and helicopters. A loser examination of pertinent investigations, however, paints a ifferent picture. Improper formulations of the equations of moion and/or misuse of the concept of mean axes do not inspire uch confidence in the usefulness of the approach. In this section, e propose to contrast the approach based on misuse of mean xes with a proper formulation of the same problem. From Meirovitch 8 , the motions of a flexible body can be escribed by means of a reference frame xyz Fig. 1 fixed in the ndeformed body and known as body. Then, the rigid-body moions are defined as three translations and three rotations of the ody axes relative to the inertial space XYZ and the elastic deforations as the displacements of points on the body relative to the ody axes. When expressed in terms of components along the ody axes, the rotational velocities are referred to as quasielocities, and the corresponding vector is denoted by . It is hown in Ref. 8 that, when expressed in terms of body-axes omponents, the translational velocities can also be treated as uasi-velocities; they are arranged in the vector V. Note that, un- ournal of Applied Mechanics om: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/201 like ordinary velocities, quasi-velocities cannot be integrated to obtain displacements 2 . Denoting by u and v the three-dimensional elastic displacement and elastic velocity vectors, respectively, where u and v are measured relative to the body axes xyz, it is shown by Meirovitch Ref. 8 that the hybrid dynamical equations of motion in terms of quasi-coordinates can be written in the compact vector-matrix form d dt L V + \u0303 dL V \u2212 C L R = F d dt L + V\u0303 L V + \u0303 L \u2212 ET \u22121 L = M t T\u0302 v \u2212 T\u0302 u + F\u0302 v + Lu = U\u0302 6 where explicit provision was made for damping, in which L is the system Lagrangian, V\u0303 and \u0303 are skew symmetric matrices derived from V and , respectively, C is a matrix of direction cosines between xyz and XYZ, R= RX RY RZ T is the radius vector from the origin OI of XYZ to the origin O of xyz, E is a matrix relating the symbolic angular velocity vector \u0307= \u03071 \u03072 \u03073 T to the angular quasi-velocity vector , T\u0302 is the kinetic energy density of the body, F\u0302 is Rayleigh\u2019s dissipation density function 11 and L is a 3 3 matrix of stiffness differential operators. Moreover, F, M, and U\u0302 are generalized force vectors, which must be expressed in terms of the same body axes components used to express the motion variables. They can be obtained from the actual distributed force vector f r , t and the discrete force vectors Fi t acting at the points r=ri i=1,2 , . . . , p by means of the virtual work expression. Discrete forces can be treated as distributed by writing them in the form Fi t r\u2212ri , where r\u2212ri are spatial Dirac delta functions 11 , so that the virtual work can be written in the form W = D fT r,t + i=1 p Fi T t r \u2212 ri RP * dD 7 where RP * is a virtual displacement vector whose expression can be obtained by considering the velocity vector of a typical point P in the body in terms of components along the body axes as follows: vP = V + r + u + v = V + r\u0303 + u\u0303 T + v 8 where r is the radius vector from O to P and r\u0303+ u\u0303 is the skew symmetric matrix derived from the vector r+u. Using the analogy with Eq. 8 with the term u\u0303T ignored as small compared to r\u0303T , we obtain MAY 2007, Vol. 74 / 499 6 Terms of Use: http://www.asme.org/about-asme/terms-of-use w w v t o w a d o T a a s f a w n g l \u201c o t m n i a e w R t s a r o w 5 Downloaded Fr RP * = R* + r\u0303T + u 9 hich is the virtual displacement vector of point P Fig. 1 , in hich R* is the virtual displacement vector of the origin of xyz, is the virtual angular displacement vector of xyz and u is the irtual elastic displacement vector of point P relative to xyz, all in erms of body-axes components. Inserting Eq. 9 into Eq. 7 , we btain W = D fT r,t + i=1 p Fi T t r \u2212 ri R* + r\u0303T + u dD = FT R* + MT + D U\u0302T udD 10 here F = D fdD + i=1 p Fi, M = D r\u0303fdD + i=1 p r\u0303iFi, U\u0302 = f + i=1 p Fi r \u2212 ri 11 re the desired generalized forces. Closed-form solutions of hybrid sets of differential equations escribing the dynamics of flexible aircraft is not within the state f the art, so that one must be content with approximate solutions. his implies invariably spatial discretization of the elastic varibles 11 . We consider spatial discretization of the system by ssuming that the elastic variables can be approximated to a reaonable degree of accuracy by series of space-dependent shape unctions multiplied by time-dependent generalized coordinates, s follows: u = , v = 12 here = r is a 3 n matrix of shape functions 11 , in which is the number of elastic degrees of freedom, is an n-vector of eneralized coordinates and is an n-vector of generalized veocities. A common misconception is to refer to the entries of as modes\u201d when in fact they are merely shape functions. Of course, ne can always try to choose the shape functions as the eigenfuncions of a somewhat related system, but that does not make them odes. It should be noted that the system described by Eqs. 6 is onlinear and subject to viscous damping. Moreover, in the case n which Eqs. 6 represent the equations of motion for a flexible ircraft, F, M, and U\u0302 include aerodynamic forces. As a result, ven after linearization, any modes are likely to be complex, hereas the entries of are real functions. In the spirit of ayleigh-Ritz, it is shown by Meirovitch 11 that any set of funcions capable of describing any possible elastic deformation of the ystem to a given desired degree of accuracy represents an acceptble set of shape functions. However, the use of shape functions epresents a mere spatial discretization process resulting in a set of rdinary differential equations. Before discretizing Eqs. 6 , we consider Eqs. 8 and 12 and rite the two forms of the kinetic energy T = 1 2 D vP TvPdD = 1 2 mVTV + VTS\u0303T + VT D vdD + T D r\u0303 + u\u0303 vdD + 1 2 TJ + 1 2 vTvdD D 00 / Vol. 74, MAY 2007 om: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/201 1 2 mVTV + VTS\u0303T + VT\u0304 + T D r\u0303 + \u02dc dD + 1 2 TJ + 1 2 T 13 where \u0304 = D dD, S\u0303 = D r\u0303 + \u02dc dD , J = D r\u0303 + \u02dc r\u0303 + \u02dc TdD, = D T dD 14 in which S\u0303 and J are the matrix of first moments of inertia and the inertia matrix, respectively, of Rayleigh\u2019s dissipation function F = D F\u0302dD = 1 2 D cvTvdD 1 2 T D c T dD = 1 2 TC 15 where C = D c T dD 16 is a damping matrix, in which c is a damping density function, and of the strain energy Vstr = 1 2 D uTLudD 1 2 T D TL dD = 1 2 TK 17 where K = D TL dD 18 is a stiffness matrix. Both C and K are symmetric. Then assuming that the Lagrangian does not depend on R and , which is true for flying aircraft, the discrete counterpart of Eqs. 6 are simply d dt L V + \u0303 L V = F, d dt L + V\u0303 L V + \u0303 L = M d dt L \u2212 T + C + K = X 19 in which, from Eq. 13 T = \u2212 \u0304TV\u0303T + D T \u02dcdD \u2212 D T\u03032 r + dD 20 and X = D TU\u0302dD 21 is the discretized generalized elastic force vector. Finally, including some obvious kinematical identities and carrying out the indicated operations, we obtain the discretized set of state equations Transactions of the ASME 6 Terms of Use: http://www.asme.org/about-asme/terms-of-use e F s b F g J Downloaded Fr R\u0307 = CTV, \u0307 = E\u22121 , \u0307 = mV\u0307 + S\u0303T\u0307 + \u0304\u0307 = 2 D \u02dcdD + mV\u0303 + \u0303S\u0303 + F S\u0303V\u0307 + J\u0307 + D r\u0303 + \u02dc dD\u0307 = D \u02dc r\u0303 + \u02dc + r\u0303 + \u02dc \u02dc dD + V\u0303S\u0303 + S\u0303V \u2212 \u0303J + \u0303 D r\u0303 + \u02dc T dD + M \u0304TV\u0307 + D T r\u0303 + \u02dc TdD\u0307 + \u0307 = \u2212 \u0304TV\u0303T \u2212 D T\u03032 r + dD \u2212 2 D T \u02dcTdD \u2212 C \u2212 K + X 22 Next, we address the problem of helicopter dynamics. To this nd, we consider the typical helicopter configuration shown in ig. 2 and assume that the main rotor consists of nm equally paced blades and the tail rotor consists of n equally spaced lades. Then, by analogy with Eqs. 6 and using the notation of ig. 2, the helicopter equations of motion can be expressed in the eneric form d dt L VO + \u0303O L VO \u2212 CO L RO = FO d dt L O + V\u0303O L VO + \u0303O L O \u2212 EO T \u22121 L O = MO t T\u0302f v f \u2212 T\u0302f u f + F\u0302 f v f + L fu f = U\u0302 f ournal of Applied Mechanics om: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/201 t T\u0302mi vmi \u2212 T\u0302mi umi + F\u0302mi vmi + Lmiumi = U\u0302mi, i = 1,2, . . . ,nm t T\u0302 j v j \u2212 T\u0302 j u j + F\u0302 j v j + L ju j = U\u0302 j, j = 1,2, . . . ,n 23 The derivation of explicit equations of motion would require a great deal of perserverance and patience, and is beyond the scope of this paper. To develop an appreciation of the nature of the equations, however, we will outline some of the steps involved in their derivation. The kinetic energy has the general expression T = 1 2 mf V f TV fdmf + 1 2 i=1 nm mi Vmi T Vmidmi + 1 2 j=1 n mj V j T V jdmj 24 where, following an orderly kinematical procedure, the velocity vectors of the individual components are given by V f r f,t = VO t + r\u0303 f + u\u0303f r f,t T O t + v f r j,t Vmi rmi,t = CmiVM + r\u0303mi + u\u0303mi rmi,t T Cmi O + M + vmi rmi,t , i = 1,2, . . . ,nm V j r j,t = C jVT + r\u0303 j + u\u0303 j r j,t T C j O + T + v j r j,t , j = 1,2, . . . ,n 25 in which VM t = V f rOM,t = VO t + r\u0303OM + u\u0303f rOM,t T O t + v f rOM,t VT t = V f rOT,t = VO t + r\u0303OT + u\u0303f rOT,t T O t + v f rOT,t 26 are the velocity vectors of the main rotor hub M and tail rotor hub T, obtained by evaluating V f at M and T, respectively. Moreover, Cmi and C j are matrices of direction cosines between the main rotor blade body axes xmiymizmi and the fuselage body axes xfyfzf and the tail rotor blade body axes x jy jz j and xfyfzf due to the spin of the rotors; both Cmi and C j depend explicitly on time. The kinetic energy is obtained by inserting Eqs. 25 and 26 into Eq. 24 and carrying out the indicated operations. A cursory examination of Eqs. 25 and 26 will reveal that the fuselage, main rotor and tail rotor are all inertially coupled and so are the equations of motion. Furthermore, it is futile to look for mean axes capable of changing this fact. Clearly, the use of mean axes for the fuselage alone, which is the least critical part of a helicopter, cannot be justified. Although we expressed the fuselage stiffness in terms of a stiffness operator matrix L f, this was merely symbolic because it is not feasible to generate a differential operator for such a complex structure as the fuselage. In practice, it is necessary to express the fuselage stiffness, in the context of a spatial discretization process, by means of a stiffness matrix generated by the finite element method. A typical main rotor blade can be modeled as a thin beam undergoing torsion about the longitudinal axis xmi and bending about axes ymi and zmi. Denoting the displacement vector for blade mi by umi= xmi uymi uzmi T, the corresponding stiffness operator matrix can be shown to have the form 11 MAY 2007, Vol. 74 / 501 6 Terms of Use: http://www.asme.org/about-asme/terms-of-use w i b t f f M t w r c w f d p b i o a l t c s t \u201c M a 3 f t c t m c h p t c w o p m 5 Downloaded Fr Lmi = \u2212 xmi GJmi xmi xmi 0 0 0 2 xmi 2 EIzmi xmi 2 xmi 2 0 0 0 2 xmi 2 EIymi xmi 2 xmi 2 \u2212 xmi Pmi xmi xmi 27 here Pmi xmi = xmi Lmi mi Cmi O + M zmi 2 d 28 s the axial force on blade mi due to the centrifugal force caused y the spin of the main rotor hub. The operator matrix L j for the ail rotor can be obtained from Eqs. 27 and 28 in an analogous ashion. Some of the other quantities, such as Rayleigh\u2019s dissipation unction densities F\u0302 f, F\u0302mi, and F\u0302 j and the generalized forces F0, 0, U\u0302 f, U\u0302mi, and U\u0302 j can be obtained by analogy with those for he aircraft, where the forces include the aerodynamic forces, hich are much more complicated than those for aircraft. In this egard, it must be pointed out that the degree of complexity inreases significantly from hover to forward flight. Indeed, in forard flight the blade velocity due to the hub rotation adds to the uselage velocity during half of the rotation and subtracts from it uring the other half. To compensate for this, the blade is made to itch accordingly. Generic equations of motion for whole flexible helicopters can e obtained by inserting Eqs. 24 \u2013 28 into Eqs. 23 and carryng out the indicated operations, which would involve a great deal f symbolic manipulations, well in excess of those for flexible ircraft. It is not difficult to see that the resulting equations are ikely to be extremely complex. Contrasting Eqs. 23 \u2013 28 with he formulation of Ref. 10 , Eqs. 5 of the present paper, one oncludes that the formulation of Ref. 10 is badly flawed, and no ensible simplification of Eqs. 23 \u2013 28 would reduce the equaions of motion to an extent that would make them resemble Eqs. 5 , not even vaguely. Hence, the contention that Eqs. 5 reflect a Coupled Helicopter Rotor/Flexible Fuselage Aeroelastic odel\u2026,\u201d as the title of Ref. 10 implies, is more than questionble. The Use of Mean Axes In deriving Eqs. 22 , a reference frame embedded in the undeormed body was used to define the rigid-body and elastic moions, as well as the forces, moments and distributed forces. This hoice seems only natural. As can be expected, the equations for he rigid-body translations, rigid-body rotations and elastic defor- ations are all coupled. There seems to be a belief that a different hoice of reference frame is able to reduce the coupling, and ence the complexity of the formulation. We wish to examine this roposition. The inertial terms can be simplified to some extent by choosing he body axes as the principal axes with the origin at the mass enter. In this case, we have D rdD = 0, D r\u0303r\u0303TdD = J 0 29 here J 0 represents the diagonal matrix of the principal moments f inertia of the undeformed body. Perhaps more extensive simlifications can be achieved, at least at first sight, by using the ean axes, defined by 02 / Vol. 74, MAY 2007 om: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/201 D udD D dD = \u0304 = 0 , D r udD = D r\u0303udD D r\u0303 dD = * = 0 30 Inserting Eqs. 29 and 30 into the second half of Eqs. 22 , the dynamical part of the state equations reduces to mV\u0307 + \u0304\u0307 = 2 D \u02dcdD + mV\u0303 + F J\u0307 + D \u02dc dD\u0307 = D \u02dc r\u0303 + \u02dc + r\u0303 + \u02dc \u02dc dD \u2212 \u0303J + \u0303 D r\u0303 + \u02dc T dD + M \u0304TV\u0307 + D T \u02dcTdD\u0307 + \u0307 = \u0304TV\u0303T \u2212 D T\u03032 r + dD \u2212 2 D T \u02dcTdD \u2212 C \u2212 K + X 31 Contrasting Eqs. 31 with the simplified equations of Refs. 6,7 , Eqs. 4 of the present paper, we conclude that Eqs. 4 do not describe any real aircraft but some fictitious one that does not exist, so that any analysis based on Eqs. 4 is an exercise in futility."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001650_0165-0114(92)90146-u-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001650_0165-0114(92)90146-u-Figure3-1.png",
+ "caption": "Fig. 3. External restrictions.",
+ "texts": [
+ " Palm / Control of a redundant manipulator using fuzz), rules 283 -4 qe~t l qe~ / / ff~4 el q Iw, I, ~ 1, > Iw21. (25) i= l Finally, the distance s~ is standardized according to a maximum distance Smax with s i s = Si/Smax. (26) With the help of such standardization a unique evaluation of internal and external restrictions is possible"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003500_ac061224o-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003500_ac061224o-Figure1-1.png",
+ "caption": "Figure 1. Amperometric ISE body design.",
+ "texts": [
+ " With both, DPV and ADPV, the charge current and the ohmic drop are reduced to a large extent with respect to single pulse techniques and cyclic voltammetry, with this reduction being even more pronounced with ADPV. Although DPV has been applied to some other types of ITIES,17,19-21 the influence of the pulse amplitude has not been studied to our knowledge, and no ADPV study of any ITIES has been reported. We show how the influence of the pulse amplitude on the DPV voltammograms can be exploited in order to obtain peaks centered within the potential window. Apparatus. The design of the sensor is shown in Figure 1. A Pt wire counter electrode was accommodated inside the inner solution compartment of a Fluka ion-selective electrode (ISE) body. The Pt wire electrode was coiled around the Ag/AgCl reference electrode, which had previously been covered by a plastic tube. The electric contact between the inner counter electrode and the external plug was made through a small hole drilled in the glass compartment used to pull an extreme of the Pt wire. This was soldered with conductive cement to a conductive band, which had previously been made all around the glass compartment with conductive cement"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001557_0167-9317(96)00004-4-Figure27-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001557_0167-9317(96)00004-4-Figure27-1.png",
+ "caption": "Fig. 27. Schematic presentation of 'key-lock' interactions between C2Cl4 as a typical organic molecule and cali:g,4)arene with different contributions to the overall interaction energy E,ot as determined from force field calculations: E,o, = s\u00ab:+ LE\",,, +LEo,oc +LEo llP +LEst, +LEbond ' For details, see [30].",
+ "texts": [
+ " Typical molecules to utilize the geometric \" key-lock' I principle are calixarenes which incorporate small organic molecules (see Fig. 7(a)). Signal transduc tion of these sensors is possible by monitoring changes in mass, capacitance , or temperature upon incorporation of organic molecules. The geometry of calixarenes may be modified by substituting atoms in the ring or by using different numbers of repeat units in the ring (Fig. 26). The molecule/ring interaction energies can be calculated with sufficient accuracy by static force field approaches applied to small rings (Fig. 27). Larger rings require the theoretical calculation of dynamically adjusted recognition centres (\" induced fits \") by molecular dynamics concepts (see 98 W. Giipel / Microelectronic Engineering 32 (1996) 75-110 Section 2.7). Such theoretical molecular design concepts become of increasing interest also for developing new pharmaceuticals (\"drug design\"). To achieve a controlled key /lock geometry, the covalent coupling of cage compounds to Au(111) via sulphur bridge bonds may be used to advantage in chemical sensors"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001376_s0967-0661(99)00084-2-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001376_s0967-0661(99)00084-2-Figure8-1.png",
+ "caption": "Fig. 8. A specimen of the #ying gyrodine with electromagnetically suspensed rotor (own angular momemtum h g \"2500 N m s) without covers: 1* the rotor of composite materials; 2* the mounting of the precession axis in the gyrocomplex casing; 3 * the gyrodine's frametype casing; 4 * the sensor and axial electromagnet; 5 * sensors and radial electromagnets.",
+ "texts": [
+ " Using numerical methods, the optimization of the stability index was carried out with an assigned oscillability index value and variation of the gyrorotor's proper angular momentum within a wide range of values (Somov, Sorokin & Kondrat'ev, 1997). Then the in#uence of factors such as #exibility, dead band, kinematic defects in the gear, quantization of the control signal, limitation on the gear stepping motor's current, etc., were investigated by both the computer-aided simulation (Somov et al., 1997) and careful experimental tests (Aref'yev et al., 1995), see Fig. 8. As a result, the amplitude of ranges for the gyrodine's precession rate and acceleration were revealed when the command and the true precession rates are shown to be close in spite of the existence of large gyroscopic torques on the gyrodine precession axis by virtue of the spacecraft rapid spatial rotation manoeuver. This means that for selected parameters of the gyrodine control laws, the assumptions of the CMG precession theory are satis\"ed for the indicated ranges of the input command signals, and the vector of the gyrocomplex's output control torque Mg in (Eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.7-1.png",
+ "caption": "Figure 1.7. Torsional vibrations of a disk.",
+ "texts": [
+ " D More applications of the foregoing methods may be found in the problems given at the end of the chapter. It is evident that the foregoing procedures assume that all quantities are expressed as functions of the time. However, this will not always be so. Later on and in some of the problem assignments, we shall have to develop additional methods to handle other situations. An important special procedure is illustrated below. Example 1.8. A circular disk of radius a is suspended by a slender rod attached to its center, as shown in Fig. 1.7. The disk is given an angular twist 00 from its natural state in frame q1 = { 0; ik }, and released to perform tor sional oscillations. The subsequent simple angular acceleration of a particle P on the rim of the disk in its rotation about the vertical axis is determined by the relation lJ = -KO, in which K is a known constant that depends on certain properties of the disk and the rod. (a) Find the velocity and acceleration of P expressed as functions of (] alone. (b) Determine the maximum magnitude of 20 Chapter 1 the angular speed of P"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000570_mssp.1996.0068-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000570_mssp.1996.0068-Figure2-1.png",
+ "caption": "Figure 2. Gearbox.",
+ "texts": [
+ " The car gearbox considered is driven by an asynchronous motor at 75 Hz. A second one brakes the differential output with a momentum of 80 Nm. The vibrations of the whole box are recorded with piezo-electric accelerometers located at 12 selected positions on the casing. Signals are low-pass filtered at 11.2 kHz and sampled with a fixed rate of 22.5 kHz. The angular position of the driving shaft is recorded by means of a pulse generator. The gearbox itself is a complex mechanical device. All five gears are mounted on two shafts (Fig. 2). The five driving wheels are fixed on the driving shaft, while the corresponding driven wheels may be kept fixed or not by using the clutch fork mechanism. The shafts are supported by three ball bearings and one roller bearing. The whole mechanism is assembled in a casing containing the lubricant. The output shaft drives the output gear which transmits motion to the differential. Only helical gears are used. The T 2 Variance of the prediction error Gear 1 0.0471 0.0021 0.0135 0.0143 0.0284 2 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002068_bf00052455-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002068_bf00052455-Figure8-1.png",
+ "caption": "Fig. 8. Mesh of gears with backlash and relevant force laws.",
+ "texts": [
+ " The equations (19) and (20) describe a multibody system with n bodies and a maximum number of (f = 6n) rigid degrees of freedom and, according to the Ritz-Ansatz (equation (4)) a certain number of elastic degrees of freedom (number of shape functions per body times number of elastic bodies). In practical applications, however, the number of degrees of freedom might be reduced drastically. For example, driveline units with straight-tooth bevels may be sufficiently modeled by rotational degrees of freedom only. To include backlashes we have to implement an algorithm which controls the contact events (Figure 8) by considering contact kinematics and contact forces. A contact at a tooth flank is going to happen if the relative distance in contact k becomes zero (equation (6)) \"Tk(PI, Pj, Ck) = 0. (32) The subsequent deflection of both teeth follow the force laws of the Figures 5 and 6, but the end of the contact is not reached, when we get again \"~k = 0. The correct condition consists in the requirement that the normal force ( ~ k e k i ) (i = 1, 2) (Figure 8) vanishes. As we have a unilateral contact problem a separation takes place when the normal force changes sign, which necessarily is not the case if 7k = 0. Due to the dynamics of the contacting bodies and due to the damping influence of the contact oil model (Figure 6) the normal force changes sign before 7k = 0, that means the tooth separation takes place when the teeth are still deflected. For separation we therefore must interpolate the force condition (Figure 8) ~kn = --eki~k = --eki (ckTk + ~kD(~k , z/k)) = O, for (i = 1,2), (33) where ffkn is the normal force vector and ~kD the damping force law due to oil and structural damping. Things are still more complicated. During free flight motion each gear wheel for example possesses its individual degrees of freedom. During contact the two gear wheels are coupled by a common force law but, additionally, in the point Ci of contact they have common coordinates too, for example Pci = PCj (equation 1) if i and j are the bodies in contact"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001656_1.1330743-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001656_1.1330743-Figure9-1.png",
+ "caption": "Fig. 9 The geometry near the trailing edge",
+ "texts": [],
+ "surrounding_texts": [
+ "3.1 Typical Simulated Results of Slider Vibration. We numerically calculated the bouncing vibrations over a random wavy surface for various values of k f , r, zc , m, s, and p. The spacing h (5zp2zd) between the contact pad displacement zp and the original disk surface displacement zd at the same x position in a quasi-steady state from 8.192 ms to 10.24 ms is focused on here. Figure 3 explains typical time histories of slider vibrations and disk surfaces for zc50.2, m51.0, s51.0, nm and p51.5. As seen in Figs. 3~a! and ~c!, the slider is almost perfectly in contact with the disk when r50.01. However, considering r510 as seen in Figs. 3~b! and ~d!, the slider separates from the disk, particularly in the case where k f51.53105 N/m. From Fig. 3~d!, we observe that the spacing becomes large when the slope of the disk surface is positive, i.e., the disk surface displacement under the center of the rear air bearing is larger than that under the contact pad. This means that the slider is following the disk surface not at the contact pad but at the center of the rear air bearing because the rear Transactions of the ASME /data/journals/jotre9/28694/ on 04/18/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F air bearing stiffness is very large. The amount of the spacing caused by the distance between rear air bearing and the trailing edge ~the contact pad! is discussed in Section 3.3. Figures 4~a! to 4~d! show the frequency response functions ~FRFs! of the contact pad displacement to the disk surface waviness, which correspond to Figs. 3~a! to 3~d!. In these figures, the lower and higher natural frequencies on the contact states are indicated by symbols ~,!. The noisy spikes seem to be caused by the bouncing vibrations. In all of the figures, we cannot observe a resonance peak at the lower natural frequency because the node point of the lower vibration mode in a contact state is close to the contact pad. Regarding the higher natural frequency, we can note a broad resonance peak when r50.01. However, when r510 as seen in Figs. 4~b! and ~d!, we note a periodical undulation of FRFs particularly in Fig. 4~d!, where k f51.53105 N/m. The valley frequencies seem to be 120, 360, 600, and 840 kHz. The intervals of those frequencies are 240 kHz which corresponds to the disk waviness whose length equals the distance between the contact pad and the center of the rear air bearing of 62.5 mm when V 515 m/s. At frequencies which are (n21/2) times 240 kHz, the phases of the disk waviness differ by p at the contact pad and the rear air bearing. Therefore, when the rear air bearing stiffness is comparable with the contact stiffness, the exciting forces from disk surface at those particular points cancel each other out at those frequencies. This would be the reason for the valley frequencies. Contrarily, the broad peaks which occur between the valleys are results from the in-phase excitation at these two points. 3.2 Effects of Friction Force on Slider Motion. Figure 5 shows the effects of the coefficient of friction m on the maximum spacing hmax and the maximum contact force Fc max when zc 50.2, s51.0 nm, and p51.5, taking the front air bearing stiffness Journal of Tribology rom: http://tribology.asmedigitalcollection.asme.org/pdfaccess.ashx?url= k f and the rear to front air bearing stiffness ratio r as parameters. The data presented in these figures are the mean values of 8 samples ~the following simulation data are also the mean values of 8 samples!. From Fig. 5, we note that the increase in m increases hmax and decreases Fc max . This is due to the friction force which acts on the contact pad at the trailing edge so that the moment of friction raises the contact pad. In addition, the effects of m on the behavior of the slider is limited. The reason for this is considered to be that the friction force acts only during the contact state. Note that the Fc max shown here includes only a normal contact force. Since the effects of m is limited, we used m51.0 for a smaller friction case and m510 for the larger friction case in the following calculations. 3.3 Effects of Design Parameters on Perfect Contact Sliding Conditions. In order to evaluate the effect of the design parameters on the perfect contact sliding condition, we examined the maximum spacing hmax and the maximum contact force Fc max for various values of k f , r, m, s, and p, taking p as a parameter (p51.0, 1.5, 2.0, and 2.5!, hmax and Fc max are expressed as functions of a standard deviation of the disk surface waviness s in Figs. 6 ~m51.0! and 7 ~m510!. In each figure, ~a! and ~b! are the case of k f55.03104 N/m, ~c! and ~d! are the case of k f51.5 3105 N/m, ~a! and ~c! are the case of r50.01, and ~b! and ~d! are the case of r510. The black lines represent hmax and the broken lines represent Fc max . The dot-dashed lines indicate hmax50 nm. The negative hmax means that the slider is always penetrating into the disk surface and vibrating below the original disk surface, i.e., the slider is sliding perfectly in contact with the disk. Considering r50.01 as seen in Figs. 6~a!, ~c!, and Figs. 7~a!, ~c!, we can get the necessary condition of s for perfect contact sliding. The boundary values of s and the maximum contact force Fc max at the same time are indicated in each figure. When referring to r510 in Figs. 6~b!, 6~d!, 7~b!, and 7~d!, we\u2019re not able to get the meaningful value of s for perfect contact sliding. This is because the rear air bearing stiffness is so large that the slider is following the disk surface not at the contact pad but at the center of rear air bearing. Since the results are different between r50.01 and r510, we will discuss the effects of the design parameters in the case of r 50.01 and r510 separately. When r50.01 ~Figs. 6~a!,~c! and Figs. 7~a!,~c!!, it can be expressed as follows: 1 Since ~a! and ~c! in Figs. 6 and 7 are similar to each other, the front air bearing stiffness doesn\u2019t affect the behavior of the contact pad. In addition, when the rear air bearing stiffness is much smaller than the contact stiffness, the effect of the rear air bearing stiffness on the contact sliding ability can be disregarded. From Figs. 6~a! and 7~a!, the boundary value of the standard deviation of disk surface waviness sb , below which the slider can JANUARY 2001, Vol. 123 \u00d5 163 /data/journals/jotre9/28694/ on 04/18/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F be sliding perfectly in contact with the disk surface, versus p is presented in Fig. 8 for the case where k f55.03104 N/m, r 50.01 and zc50.2. It is apparent that the friction coefficient decreases sb . 2 The maximum contact force Fc max at the boundary of the perfect contact sliding condition are independent from the disk surface waviness parameters ~s and p! and the rear air bearing stiffness; Fc max50.95 mN in Figs. 6~a! and ~c!, and Fc max 50.40 mN in Figs. 7~a! and ~c!. This is because contact force is at its maximum when the contact pad is at the most penetrating position, which does not depend on the disk surface waviness parameters but on the contact stiffness kc , the static contact force Fc0 and the coefficient of friction m. As seen in Figs. 4~a! and ~c!, the FRFs of the contact pad which relate to the disk surface are similar to the single-degree-offreedom ~1-DOF! model of a contact slider. Therefore, we predicted sb of the 2-DOF model with a weak rear air bearing by using the closed form solution of the perfect contact sliding condition of the 1-DOF contact slider on a random disk surface @12#. In this prediction, the higher natural frequency in a contact state is regarded as the contact resonance frequency of the 1-DOF model. The sb value predicted by the 1-DOF model is shown in Fig. 8 for comparison. Taken from Fig. 8, we note that the differences of 1-DOF analysis from the simulated results are less than 10 percent for m51.0 and less than 30 percent for m510. Therefore, it can be said that the perfect contact sliding condition of the 2-DOF model is well predicted by the 1-DOF analysis when the front and rear air bearing stiffnesses are much smaller than the contact stiffness. 164 \u00d5 Vol. 123, JANUARY 2001 rom: http://tribology.asmedigitalcollection.asme.org/pdfaccess.ashx?url= Next, we have discussed the spacing in the case of r510. As seen in Figs. 6~b!, 6~d!, 7~b!, and 7~d!, perfect contact sliding is almost impossible unless s50. This is because the slider is following the disk surface not at the contact pad but at the center of the rear air bearing when the rear air bearing stiffness is comparable with the contact stiffness, as stated in Section 3.3. When the contact damping ratios are as large as 0.2, it is thought that the spacing can be evaluated approximately from only the geometrical Transactions of the ASME /data/journals/jotre9/28694/ on 04/18/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F relation with the assumption that the slider is following perfectly the disk waviness at the rear air bearing center. Figures 9~a! and ~b! show the models of the geometry near the trailing edge of a flat disk and wavy disk, respectively. Since the spacing hr at the rear air bearing is assumed to be constant, the spacing hg at the trailing edge ~contact pad! is given as follows: hg5zd~ t ,xcr!2zd~ t ,0!2dr , (6) where dr is given by Fc0 /kr . If the micro waviness of a disk surface is Gaussian, the standard deviation sg of (zd(t ,xcr) 2zd(t ,0)) can be obtained by its root mean square and is given by sg5A2~s22R~xcr!!, (7) where R(xcr) is a covariant function given as R~xcr!5E 0 ` A~ f d!cosS 2pxcr f d V D d f d , (8) where A( f d) is the frequency component of the disk surface waviness. A( f d) can be calculated from the standard deviation of the disk surface waviness s and the smoothness parameter p. Since the spatial distribution of the disk waviness is Gaussian, the maximum value of (zd(t ,xcr)2zd(t ,0)) can be given by 3sg . Therefore, the maximum spacing hg max is as follows: hg max53sg2dr . (9) Figure 10 shows hg max as a function of xcr when s51.0 nm, dr 50.33 nm and p51.0, 1.5, 2.0, and 2.5. In comparison, the simulated results of hmax for p51.0, 1.5, 2.0, and 2.5, when s51.0 nm, k f51.53105 N/m, dr50.33 nm, r510, m51.0, and xcr 562.5 mm ~from Fig. 6~d!! are shown in Fig. 10 by the symbols ~L!. The symbols ~L! indicate hmax for the cases of p51.0, 1.5, 2.0, and 2.5 from up to down, respectively. Seen in Fig. 10, it can be said that this estimation agrees well with the numerical simulation when p51.5;2.0. The difference between the estimation and the simulation is considered to be caused by the dynamic response of the slider. Taken from Fig. 10, xcr should be less than 8 mm in this particular situation where s51.0 nm and p52.5, in order to achieve perfect contact sliding in this case. However, if the contact pad Journal of Tribology rom: http://tribology.asmedigitalcollection.asme.org/pdfaccess.ashx?url= can be separated from the disk surface by 2 nm, xcr can be designed as 50 mm when s51.0 nm and p51.5. Furthermore, the perfect contact sliding can be obtained if we can increase the static penetration depth dr , contact force Fc0 , or decrease the standard deviation of the disk surface waviness s so that dr .3sg will hold. 3.4 Effects of Static Equilibrium Pitch Angle on Flying Height of Front Air Bearing Surface. In the previous sections, we numerically simulated the behavior of a slider for u0 5300 mrad. However, the tri-pad sliders with a smaller pitch angle are usually used for HDDs. If the pitch angle is small, the front air bearing surfaces of the sliders tend to make contact with the disk surfaces more easily. This may cause a \u2018\u2018head-crash\u2019\u2019 because the area of the front air bearing surface is much larger than that of the contact pad and the large friction force or stiction force is generated at the front part of the slider when the front air bearing surface makes contact with the disk surface. In this section, we examined the relationship between the static equilibrium pitch angle and the flying height of the front air bearing surface and we have discussed the design conditions of the static equilibrium pitch angle. The minimum flying height of the center of the front air bearing surface h f min is shown in Fig. 11 as a function of the static equilibrium pitch angle u0 when k f51.53105 N/m, zc50.2 s51.0, p51.5, r50.01, 10, and m51.0, 10. The relationship between h f min and u0 is almost linear in Fig. 11. One of the reasons for this is the assumption that the air bearings have linear springs. From Fig. 11, it can be stated that the flying height of the front air bearing decreases when r and m are large. This is due to the moment of friction force which has the effect of decreasing the pitch angle and resulting in the decrease in the flying height. In addition, in order to maintain h f min higher than 40 nm and to prevent for the front air bearing surface from contacting with disk surfaces, the static equilibrium pitch angle should be larger than about 70 mrad. 3.5 Design of Tri-Pad Contact Slider. Based on the simulated results, we will discuss the design condition of the tri-pad contact sliders and the disk surfaces in this section. When m is larger than 0.3, yielding occurs at the surface of the weaker body of the two mating bodies by shear stresses @20#. Therefore, we use the maximum friction force mFc max for the criterion of wear durability in this study. At first, we will discuss the design condition pertaining to the case of r50.01. In this case, the slider has a very weak rear air bearing, like the \u2018\u2018T \u2019\u2019 type slider @5#. The conditions of the disk waviness parameters necessary for perfect contact sliding can be obtained from the numerical simulation results as stated in Section 3.3. The boundary values of the standard deviation of the disk waviness sb for perfect contact sliding and the maximum friction force mFc max at the boundary are presented in Fig. 12 as a function of p when k f51.53105 N/m, r50.01, m51.0, 10, and zc JANUARY 2001, Vol. 123 \u00d5 165 /data/journals/jotre9/28694/ on 04/18/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F 50.1, 0.2. The results for the case of k f55.03104 N/m are not shown here because they are not different from the results for the case of k f51.53105 N/m. In Fig. 12, solid lines represent sb for perfect contact sliding, whereas broken lines represent maximum friction force at the boundary conditions. From Fig. 12, we note that the larger zc , the larger p and the smaller m is better for perfect contact sliding. Almost the same values of sb can be obtained in both cases where zc50.1 and m51.0, and zc50.2 and m510. But the maximum friction force mFc max of the latter is about 4 times as large as that of the former. Here, the slider material is assumed to be Al2O3\u2022TiC ~E1 5385 GPa, v150.3! and the disk material is assumed to be glass ~E2571 GPa, v250.21!. Then, the area of the contact pad S becomes 161 mm2 for kc51.53106 N/m by using Eq. ~1!. Taken from Fig. 12, the maximum friction forces mFc max are about 1 mN and 4 mN for m51.0 and m510, respectively. Therefore the maximum shear stress acting on a contact pad area uniformly are 6.1 MPa and 25 MPa for m51.0 and m510, respectively. The surfaces of the contact pad and the disk should be able to withstand these shear stresses. For example, when it is assumed that the friction force of 4 mN acts on the real area of the contact uniformly and that the ratio of the real area of contact to the contact pad area is 0.01, the shear stress on the surface of the real contact area is 2.5 GPa. In general, the yield shear stress is a half of the yield tensile stress. Therefore, the yield tensile stress of the weaker material of the contact pad and the disk should be more than 5 GPa in this specific case. As for the case of r510, i.e., a tri-pad slider which has a strong rear air bearing, it is difficult to achieve perfect contact sliding because of the micro waviness if the rear air bearing center is far from the contact pad. In addition, the maximum contact force will increase with the increase in the distance between the rear air bearing center and the contact pad because of the increase in the penetrating depth due to the micro waviness. Therefore, the reduction of the distance is important in terms of reducing both the spacing and the maximum contact force. From the discussion described above, when designing a tri-pad type contact slider, we should make the distance between the rear air bearing center and the contact pad equal to zero and make the rear air bearing stiffness large. Otherwise, we should make the rear air bearing stiffness much smaller than the contact stiffness."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002517_1.1515324-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002517_1.1515324-Figure5-1.png",
+ "caption": "Fig. 5 Analytical model of a link at the instant of collision",
+ "texts": [
+ "4 Angular Velocity Variation Caused by Foot Exchange. In this analysis, it is assumed that the toe collision is plastic and the foot exchange takes place instantly for the sake of analytical simplicity. As shown in Fig. 4, u\u0307 i p4 represents the angular velocity of link i at the moment right before the foot exchange ~posture 4 in Fig. 2!, whereas u\u0307 i p5 stands for the angular velocity of link i at the moment right after the foot exchange ~posture 5 in Fig. 2!. The analytical model of link i at the instant of the foot exchange is shown in Fig. 5. Pi and Pi11 are the impulses caused by the collision at the joints i and i11, respectively. The impulsemomentum equations for link i are written in the forms, mi~v ix p52v ix p4!5Pix2P (i11)x mi~v iy p52v iy p4!5Piy2P (i11)y (4) I i~ u\u0307 i p52 u\u0307 i p4!5ai3Pi1~ li2ai!3Pi11 556 \u00d5 Vol. 124, DECEMBER 2002 rom: http://dynamicsystems.asmedigitalcollection.asme.org/ on 01/28/201 where v i p4 is the mass center velocity of link i at the moment right before foot exchange and vi p5 is the mass center velocity of link i at the moment right after the foot exchange"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000909_027836499901800506-Figure11-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000909_027836499901800506-Figure11-1.png",
+ "caption": "Fig. 11. Grasp on a pyramid with four contact points: the optimal grasp (a); and an unfavorable condition (Td = \u2212j) (b).",
+ "texts": [
+ "5, 0) as the optimal position (Fig. 10a), close to which a minimumfriction coefficient of 0.72 (amax = 5) is required to ensure contact stability. It is interesting to note that the most unfavorable condition is obtained when the torque Td = \u2212i is exerted on the pyramid. Figure 10b reports the values of the normal and tangential forces that are necessary to balance the disturbance torque Td = \u2212i by minimizing the friction coefficient. If the pyramid were to be grasped with four digits, the optimal grasp points (Fig. 11a) would be: P1 (0.5, 0, 0), P2 (0, 0.5, 0), P3 (\u22120.5, 0, 0), and P4 (0, \u22120.5, 0), with fmin = 0.61 (amax = 5). In this case, the most unfavorable condition is obtained when a torque directed along the x- or y-axis is exerted on the object. Figure 11b shows the forces that the fingers would have to exert to balance the torque. The influence the maximum normal force exerted by each digit (amax) has on contact stability may be examined by means of the optimization algorithm. Figure 12 shows the minimum-friction coefficient value required to ensure stability (fmin) as a function of amax for an optimal grasp with three and four contact points. It is interesting to observe that both curves have fmin = 0.5 as an asymptotic value, and therefore a friction coefficient greater than 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000704_a:1008228120608-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000704_a:1008228120608-Figure5-1.png",
+ "caption": "Figure 5. Example of a non-periodic motion in the plane X1\u2013X2 (a) and of the corresponding event map (b).",
+ "texts": [],
+ "surrounding_texts": [
+ "If the driving velocity is small the points lying on the line AC into the failure locus represent all the transient motions once the possible global slip phases have ceased [7]. The stretch length d may vary between 0:6764 and 0.6764 which correspond to the points C and A, respectively, of the failure locus of Figure 2. Choosing a grid of initial conditions on this line, it is possible to investigate the global dynamics of the system. Figure 6 is an illustration of the global dynamic behaviour of the system by means of the one-dimensional map. In Figure 6 the thin lines indicate the transient behaviour whereas the thick lines are composed by points belonging to the steady state behaviour of the system. There exist (at least) two attractors, indicated by the numbers \u20181\u2019 and \u20182\u2019, so that the interval CA, where the map is defined, is divided in two basins of attraction; the two sub-intervals B1 and B2 constitute the basin of the attractor \u20182\u2019, the other sub-intervals are the basin of attraction of the attractor \u20181\u2019. The one-dimensional map will be utilised to study the evolution of the attractor \u20182\u2019 as Vdr varies. Figure 7 shows the bifurcation diagram of the attractor \u20182\u2019 in a portion of the range of small driving velocities; starting from Vdr = 0:0846 the attractor undergoes a period-doubling cascade giving birth to an apparently chaotic attractor which suddenly disappears for Vdr 0:08058. A sequence of one-dimensional maps in the non-periodic region can be seen in Figure 8; the shape of those maps constitutes evidence of the chaotic nature of the system. For values of the driving velocity close to Vdr = 0:082377 (see bottom right of Figure 8) and above, the steady state part of the one-dimensional iterated mapping is composed of two (or more) separated branches; see also Figure 9a. This separation into two branches clearly rules out the existence of odd periodic orbits since f(a) :! b, f(b) :! a, and a \\ b = ;, where a and b are the two intervals where the permanent portion of the map is defined. The only exception is a fixed point in between the two branches (not shown). The map is, however, still continuous as the transient part of the map shows (not shown on Figures 8 and 9). Considering Figure 9b and the illustrative trajectories shown, it is evident that the map possesses a so-called snap-back repeller, or in more traditional terms a homoclinic orbit to the unstable fixed point; the fixed point is, of course, a fixed point for the second iterate of f , and in reality is a prime period-2 orbit. The fixed point for the second iterate is located at approximately d = 0:1624. The snap-back repeller is sufficient for the existence of chaos [11, 18]. That is, there exist periodic points of any prime period (for the second iterate), and uncountably many orbits that are not even asymptotically periodic. Finally in some cases it seems possible to detect a partition of intervals a, b, and c on the interval of definition of the \u2018permanent\u2019 map, as suggested by Figures 10a and 10b, corresponding to the values Vdr = 0:0811 and Vdr = 0:0813. It is reasonable to hypothesise the existence of a map with a superstable period-4 orbit which was approximately found for Vdr = 0:0812 (Figure 10c). Such an orbit divides the interval of definition of the \u2018permanent\u2019 map in three sub-intervals a, b, c which are mapped in the following way: f(a) b; f(b) c; f(c) a [ b [ c: (6) The transition matrix A (or Markov graph) is constructed according to the rule: Aij = 1 if f(ai) aj and zero otherwise: A = 0 B@ 0 1 0 0 0 1 1 1 1 1 CA : (7) The construction of the transition matrix enables us to count the number of period-m orbits. If Nm denotes the number of fixed points of fm then: Nm = tr(Am): (8) Part of these Nm orbits are trivial, i.e. they are orbits of periods dividing m. Subtracting the number of trivial points from Nm and then dividing by m makes it possible to obtain the number of the period-m orbits [15]. For example, tr(A2) = 3; there are three fixed points of f2, of those one is a fixed point of f , the trivial period-2 orbit and then there exists a true period-2 orbit; tr(A3) = 7; of those seven fixed points one is trivial and the other six correspond to two period-3 orbits; tr(A6) = 39; f6 has 39 fixed points: one is the fixed point of f , two are the period-2 orbit, six are the two period-3 orbits so that the number of non-trivial fixed points is 30 corresponding to five period-6 orbits. The structure of the Markov graph shows that there are periodic orbits of any period, which are believed to be unstable."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003441_978-1-4613-9030-5_27-Figure27.4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003441_978-1-4613-9030-5_27-Figure27.4-1.png",
+ "caption": "Figure 27.4: First fonn of deflection due to instability of the spine (back view): a) the whole spine; b) ver tebrae T8-Ll.",
+ "texts": [
+ "3 presents the spine system displace ments in the state of stability (only vertebrae are shown) deformed by load (in the considered case all muscles work). Because of the symmetry of both the investigated system and the applied load in respect to the sagittal plane, displacements in the frontal plane equal zero. It can be noticed that, in comparison with Figure 27.1a, the load causes an increase of the spine curves (kyphosis and lordosis). When the load is increased by about 20% the spine system loses its stability. A form of spinal deflection is shown in Figure 27.4. Because of linearization of the equations, only the proportions of the displacements and rotation angles of in dividual vertebrae are known, not their absolute values. The form shown in Figure 27.4 is charac- terized by large displacements of vertebrae TlO and T11 and simultaneous rotation of all vertebrae. The rotation angle of vertebrae. beginning at the L5, increases in the lumbar section and attains its maximum value at the Tll. Then it decreases in the thoracic section. The relative rotation axes of the vertebrae are beyond the spinal column. The spine deformation visible from behind is mostly due to the fact that during the rotation the location of the natural spine curves changes (lordosis and kyphosis are now in different planes)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003613_j.bios.2005.08.010-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003613_j.bios.2005.08.010-Figure5-1.png",
+ "caption": "Fig. 5. Cyclic voltammograms of a FAD/zinc oxide film adhered to a glassy carbon electrode in 10 ml of a deoxygenated phosphate pH 7.0 aqueous solution with: (A) [H2O2] = (a) 0 M; (b) 0.05 M; (c) 0.1 M; (a\u2032) bare glassy carbon electrode and [H2O2] = 0.1 M; (B) a FAD/zinc oxide film in a deoxygenated pH 7.0 aqueous solution with: (a) hemoglobin and H2O2 absence; (b) 4.25 \u00d7 10\u22126 M of hemoglobin; (c) 4.25 \u00d7 10\u22126 M hemoglobin added 0.25 M H2O2; (a\u2032) bare glassy carbon electrode with 4.25 \u00d7 10\u22126 M hemoglobin added 0.25 M H2O2. Scan rate = 0.1 V/s.",
+ "texts": [
+ " The EQCM and cyclic voltammetry were used to study the in situ growth of the FAD/zinc oxide films and the results showed that the hemoglobin did deposit on the FAD/ZnO film and enhanced the electrocatalytic reduction activity of oxygen through the FADH2/FAD redox couple. Fig. 3A explains the consecutive cyclic voltammetry of a FAD/zinc oxide film on the gold electrode in a pH at 7.0 aque- Fig. 3. (A) Repeated cyclic voltammograms of a FAD/zinc oxide film on gold electrode in a solution containing 1 \u00d7 10\u22125 M FAD in an aqueous 0.1 M Zn(NO3)2 pH 7.0. Scan rate = 0.02 V/s. (B) The change in EQCM frequency, recorded concurrent with the consecutive cyclic voltammograms of Fig. 5A. (C) Fig. 5A FAD/zinc oxide film in the (a) absence of oxygen and (b) after adsorbed hemoglobin and presence of oxygen in a pH 7.0 phosphate aqueous solution; (a\u2032 and a\u2032\u2032) bare glassy electrodes in the solutions of absence and presence of oxygen, respectively. Scan rate = 0.1 V/s. 2 edox couple in the absence of hemoglobin (Fig. 2B(b)). The ous solutions. Fig. 3B demonstrates the change in the EQCM frequency recorded during the first 10 cycles of the consecutive cyclic voltammetry. The increase in the voltammetric peak current observed in Fig",
+ " According to the experimental results, the reaction pathways for spectroelectrochemistry of hemoglobin using FAD as a catalyst are as follows: FAD/ZnO/GC electrode + 2H+ + 2e\u2212 \u2192 FADH2/ZnO/GC (6) 2Hemoglobin (FeIII) + FADH2/ZnO/GC \u2192 2Hemoglobin (FeII) + FAD/ZnO/ + 2H+ (7) 3 a a c c I \u2212 i t film. The electrocatalytic reduction of H2O2 by the FAD/ZnO film in presence of hemoglobin in a pH 7.0 buffered solution was studied using cyclic voltammetry with the concentration of 4.25 \u00d7 10\u22126 M hemoglobin added with 0.25 M H2O2. The electrochemical responses are shown in Fig. 5B. The electrocatalytic peak current IPcat (the cathodic peak potential, EPcat, at a potential of about \u22120.47 V) of the FAD/ZnO film of FADH2/FAD redox couple increased noticeably. This arose from the direct electrocatalytic reduction of H2O2 through the FADH2, catalyzed by the FAD/ZnO film and enhanced by the hemoglobin. This behavior obtained from the direct electrocatalytic reduction of H2O2 enhanced by the hemoglobin. Then, the electrocatalytic reduction of O2 was performed by the hemoglobin and FAD/ZnO",
+ " A possible mechanism for the reduction of H2O2 by the heme protein film is that the heme\u2013Fe(III) complex is oxidized to a compound denoted as \u201ccompound I\u201d, i.e., heme\u2013Fe(III) + H2O2 \u2192 compound I + H2O. Then, compound I reacted with H2O2 to form the heme\u2013Fe(III) and O2, i.e., compound I + H2O2 \u2192 heme\u2013Fe(III) + O2 (Taniguchi et al., 1992). .5. Electrocatalytic reduction of H2O2 by FAD/ZnO film nd hemoglobin The electrocatalytic reduction of H2O2 by a FAD/ZnO film nd hemoglobin in pH 7.0 buffered solution was studied by yclic voltammetry between 0 and 0.7 M. The electrochemial responses are shown in Fig. 5A. The catalytic peak current Pcat (the anodic peak potential, EPcat, at a potential of about 0.47 V) of the FAD/ZnO film of FADH2/FAD redox couple ncreased. This arose from the direct electrocatalytic reducion of H2O2 through the FADH2 catalyzed by the FAD/ZnO The electrocatalytic reduction of O2 was, however, performed by the hemoglobin and FAD/ZnO. The electrocatalytic reduction of O2 by FAD/ZnO film using the cyclic voltammetry and rotating ring-disk electrode method in pH 7.0 phosphate aqueous solution in the presence of oxygen (saturated with air) was performed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003972_robot.2006.1642071-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003972_robot.2006.1642071-Figure5-1.png",
+ "caption": "Fig. 5. Soft-fingered grasping",
+ "texts": [
+ " Let kij and bij be the elastic and viscosity coefficients, respectively, of the soft interface between i-th and j-th masses, and mi represent the mass of Pi. Additionally, let Lij be the natural length of the soft interface between i-th and j-th masses. Physical parameters of the soft interface and mass points are time-invariant and positive. By varying the physical parameters, the model can be used to represent various cases. For example, when we use a high stiffness value as a parameter k13, the model describes the case of a soft-fingered robotic hand grasping a rigid object as shown in Figure 5. C. Formulation of simultaneous control along the x-axis In this section, we formulate the simultaneous positioning of viscoelastic object. As an example, we use PID control for the positioned points nearest to the respective manipulated points as a control law. Also, we use force values as manipulated variables. At time t, the dynamic equation of the masses can be expressed as: \u23a7\u23aa\u23aa\u23aa\u23aa\u23a8 \u23aa\u23aa\u23aa\u23aa\u23a9 m0v\u03070 = k01(x1 \u2212 x0 \u2212 L) + b01(v1 \u2212 v0) + fdrive 0 , m1v\u03071 = \u2212k01(x1 \u2212 x0 \u2212 L) \u2212 b01(v1 \u2212 v0) +k13(x3 \u2212 x1 \u2212 L) + b13(v3 \u2212 v1), m3v\u03073 = \u2212k13(x3 \u2212 x1 \u2212 L) \u2212 b13(v3 \u2212 v1) +k32(x2 \u2212 x3 \u2212 L) + b32(v2 \u2212 v3), m2v\u03072 = \u2212k32(x2 \u2212 x3 \u2212 L) \u2212 b32(v2 \u2212 v3) + fdrive 2 , (1) where f drive i is the driving force for the respective manipulated points"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003808_jjap.44.1875-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003808_jjap.44.1875-Figure1-1.png",
+ "caption": "Fig. 1. Structures of a two-domain HAN cell treated by ion beam irradiation.",
+ "texts": [
+ " However, an ionbeam-treated multidomain HAN cell does not suffer from such a problem, because the same kind of organic material is coated on both substrates. A multidomain HAN cell can be fabricated with two different structures using an ion beam. First, the polyimide surface irradiated with using an ion beam with a low energy and a high current density aligns LC vertically. On the other hand, the polyimide surface irradiated with using an ion beam with a high energy and a high current density aligns LC horizontally. Each pixel is divided into two parts and each of the parts is exposed to an ion beam in a reverse direction, as shown in Fig. 1(a). Second, both layers are divided into two parts, one of which is a homeotropically aligned by low-current ion beam irradiation and the other is a homogeneously aligned by high-current ion beam irradiation, as shown in Fig. 1(b). Asymmetry in viewing angle in a conventional HAN LC cell can be compensated by the two-domain structure because a two-domain HAN cell is optically identical to a cell, as shown in Fig. 1. Figure 2 shows a pixel with two domains divided by an ion beam with an experimental setup shown in Fig. 1(b). The domain size is 2000 mm 2000 mm and the ion beam conditions are: For horizontal alignment, the ion beam energy, ion beam exposure time, incident angle and beam current density are 200 eV, 30 s, 30 , and 80 mA/cm2, E-mail address: thyoon@pusan.ac.kr Japanese Journal of Applied Physics Vol. 44, No. 4A, 2005, pp. 1875\u20131878 #2005 The Japan Society of Applied Physics 1875 respectively. For vertical alignment, the ion beam energy, ion beam exposure time, incident angle and beam current density are 80 eV, 10 s, 10 , and 20 mA/cm2, respectively. Figure 2(a) shows the front view of the sample with the structure shown in Fig. 1(b) in the field-off state. Except for a disclination line in the center generated by the mismatch of alignment between the top and the bottom layers, the brightness of the two domains in front of a HAN cell is nearly the same. Figures 2(b) and 2(c) show the right- and the left-hand side views in the field-off state, respectively. These images show obviously that, as depicted in Fig. 1(b), the form of LC directors in the two domains is symmetric to each other. Figure 2(d) shows the front view of the sample in the field-on state (7V). Both domains show an excellent dark state. Figures 2(e) and 2(f) show the right- and the left-hand side views in the field-on state (7V), respectively. They also show obviously that the form of LC directors in the two domains is symmetric to each other. Figures 3(a) and 3(b) show iso-contrast contours of a cell and a two-domain HAN cell calculated without any optical compensation with a pixel size of 200 mm 100 mm"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002546_jpsj.73.1082-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002546_jpsj.73.1082-Figure4-1.png",
+ "caption": "Fig. 4. Schematic representation of experimental procedure to check whether some chemical as an inhibitor and pacemaker cells are necessary for concentric ring pattern formation or not.",
+ "texts": [
+ " If so, the local cell density of bacteria corresponds to an activator. Moreover, it is necessary for the formation of the concentric ring-like pattern that there are pacemaker cells which secrete some chemical periodically at the center of the concentric ring-like colony. Then, the following experiment can be considered in order to check whether any chemical as an inhibitor and pacemaker cells for the appearance of concentric ring exist or not: Cut a colony together with an agar plate as shown in Fig. 4(a) along the dotted lines in Fig. 4(b) during its growth. Then the part of the colony represented by the darker region in Fig. 4(b) is isolated from cells at the center spot which are considered to be a pacemaker for concentric ring pattern formation. If some chemical and pacemaker cells are needed, this isolated part of the colony must grow and produce a colony whose morphology is different from the previous one. In the case of P. mirabilis, it has been confirmed that the colony on the isolated part grows into almost the same concentric ring pattern as the colony on the rest part. Therefore, it is concluded that macroscopically any chemicals and the pacemaker cells are not necessary for the formation of the concentric ring-like colony"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.17-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.17-1.png",
+ "caption": "Figure 4.17. Cylindrical coordinates and the cylindrical reference frame,",
+ "texts": [
+ " The rectangular coordinate system is a 268 Chapter 4 familiar example of an orthogonal coordinate system in which a point P is located by specification of three directional numbers obtained by measurement of three mutually perpendicular distances along straight coor dinate lines. And this rudimentary coordinate system is used to construct other orthogonal coordinate systems in which some, or possibly all, of the coordinate lines may be curved; and hence these are called curvilinear coor dinate systems. In particular, the cylindrical coordinates (r, \u00a21, z) of a point P in a rec tangular Cartesian frame iP = { F; Id are illustrated in Fig. 4.17. To locate P by its cylindrical coordinates in t'P, measure from Fa radial distance r along the X axis, then trace that end point along a circular arc of radius r through an angle \u00a21 about the Z axis, and, finally, from its place in the XY plane, trans late the point a distance z along a straight line parallel to the Z axis. This program brings us to the unique location of Pin t'P. It is seen in Fig. 4.17 that for a fixed value of r the locus swept out by all such points is a cylindrical sur face of radius r in t'P; therefore, as mentioned above, the three measure num bers r e [0, oo ), \u00a21 e [0, 2n ], and z e (- oo, oo) are named cylindrical coor dinates. Because one of the coordinate lines traversed by the tracing point is a curved line, the cylindrical coordinate is a curvilinear coordinate system. When z = const, the cylindrical coordinates sometimes are called plane polar coordinates. Another reference frame 1/1 = { 0; e\" e9 , ez }, called the cylindrical reference frame, may be introduced to describe this system. The origin for this frame may be chosen anywhere; however, for simplicity, we shall take 0 at F in t'P. The three orthogonal lines labeled r, \u00a21, and z in Fig. 4.17 are parallel to the directions of the orthonormal basis for 1/1, which is shown at P for con venience. The unit vector e, is always in the direction of increasing values of the radius vector r in the XY plane; and ez = K is the usual unit vector parallel to the z axis in the direction of increasing values of z = Z. The unit vector e9 = ez x e, is in the direction of increasing values of the central angle \u00a21, and it Motion Referred to a Moving Reference Frame and Relative Motion 269 is tangent at P to a circle of radius r parallel to the XY plane"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001880_37.664656-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001880_37.664656-Figure5-1.png",
+ "caption": "Fig. 5. Example Case II system.",
+ "texts": [
+ " In the experiments, both the regulation cases were performed for long durations (more than two hours) to check for divergence or instability. It was found that the system consistently exhibited error convergence and stability. The AISE values and eqor bounds for the trackmg case shown in Table l indicate the advantages of the reported adaptive technique over the other two. T O Example Case I1 The Example Case I1 hardware system consists of a nonlinear load driven by a DC'motor. The nonlinear load is a four-bar linkage (Fig. 5a) with\u20ac$ being the input which is controlled by a DC motor, and\u20ac$, 8, arelfunctions of 8,. Since friction in the four-bar linkage load is position- and velocit pressed as Tf = Tf(\u20ac12,62,sgn(6>) Th IEEE Control Systems where Tm is the DC motor control torque, f ( 8 , ,e,) and b( 0,) are known nonlinear functions, and A(@,, 0,) is the unknown non- linear function due to friction and other state dependent uncertainties. Fig. 5b is a representative open-loop dynamics plot showing the large variation in velocity for a constant input torque, as compared to a constant output velocity expected for Example Case I. It shows the nonlinear position dependent nature of the dynamics, details of which are given in Table 2. Based on the scheme shown in Fig. 1, the input for identification is selected as U = U' i- (Jeq - f , (0 , ) ) ( -20, -8) for the actual plant and U = U' + (J., - f,( \u20acI2))[- 26 ' -0 ) forthenominal model, where U' is the training signal, which is a random step excitation input with a maximum magnitude of 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000569_s0045-7949(98)00004-2-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000569_s0045-7949(98)00004-2-Figure3-1.png",
+ "caption": "Fig. 3. The undeformed and deformed shapes of a rectangle undergoing a rigid-body rotation: (a) undeformed and (b) deformed.",
+ "texts": [
+ " Using the fact that d(dmn) = 0 and Omn=Onm [2], we obtain \u00ffO12 1 l2 j ~2 jn d 1 l1 j ~1 jn \u00ffO21 1 l1 j ~1 jn d 1 l2 j ~2 jn \u00ffO12d 1 l1 j ~1 jn 1 l2 j ~2 jn \u00ffO12d 1 l1 j ~1 1 l2 j ~2 O12d 2A12 O12dA12 O21dA21 33 Hence, Equation (30) can be rewritten as dP V OijdAij dV 34 which shows that Almansi strains are work-conjugate to Almansi stresses. To show the objectivity of di erent strain measures, we consider an in\u00aenitesimal rectangle undergoing a rigid-body rotation y with respect to the axis x3, as shown in Fig. 3. It follows from Fig. 3 that dy1 dx 1 cos y 35a and the displacement component v1 of the points o, a, and g are vo1 0, va1 dx 1 cos y\u00ff 1 , vg1 \u00ffdx 1 sin 2y 35b Using Equations (35a)\u00b1(b) and the de\u00aenitions of strains shown in Equations (4), (9) and (24), we obtain e\u030211 e11 @v1 @x 1 va1 \u00ff vo1 dx 1 cos y\u00ff 1 6 0 36a l11 @v1 @y1 va1 \u00ff vg1 dy1 1\u00ff cos y 6 0 36b Hence, displacement gradients e\u00c3ij, engineering strains eij and in\u00aenitesimal strains lij are non-objective measures. From Equation (32) one can see that, if there are only rigid-body motions, lk=1, jm\u00c4 jn\u00c4=dmn and Amn=0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003241_tasc.2004.830317-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003241_tasc.2004.830317-Figure1-1.png",
+ "caption": "Fig. 1. Cross section of the HTS rotor. (a) Straight part (b) end part.",
+ "texts": [
+ " In order to satisfy high efficiency and high starting torque, critical current of the short bars made of HTS tapes, that is, number of HTS tapes which is connected in parallel, must be decided carefully. If the critical current is too large, HTS bars will not quench during the starting. If it is too small, it will not recover from quench after starting. Two HTS tapes which were connected in parallel were used for one bar. Critical current of one HTS tape was 115 A at self field. To accommodate the flat HTS tape, shape of the slot of the HTS rotor should be different from that of the conventional motor. Cross section of the HTS rotor is given in Fig. 1. Figs. 1(a) and (b) show the cross section of straight part and the end part, respectively. Outer diameter and inner diameter of the HTS rotor were 78 mm and 22 mm, respectively. Fig. 2 shows the cage rotor of the conventional and the HTS motor. HTS tapes for the short bars are soldered to the HTS tapes for the short rings. Electrodynamometer was coupled to the motor to apply the load. Fig. 3 shows the test system, where the HTS motor, the electrodynamometer and the cryostat are shown. Electro-dynamometer was placed on the top flange of the cryostat"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001746_0005-1098(92)90062-k-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001746_0005-1098(92)90062-k-Figure1-1.png",
+ "caption": "FIG. 1. The concept of MVSC.",
+ "texts": [
+ " In this paper, we propose a new approach, the modified variable structure controller (MVSC) to eliminate the chattering phenomenon. The concepts of the MVSC will be given in the following section. 2. Some concepts o f the M V S C We are now in a position to propose a modified variable structure controller (MVSC). The central concept of MVSC is based on the utilization of two switching surfaces, S 1 = 0 and S~ = 0, to establish a sliding sector. For ease of statement, in the following we shall give an explanation by using a system with state space as indicated in Fig. 1. The state space is partitioned into three parts by two switching surfaces. In Part tr, the RP lies outside the sliding sector, i.e. in the hitting phase S1S 2 > 0, a feedback control law is adopted to force the state trajectories of the system hitting the sliding sector at some time t > 0 subject to any initial condition. It is important to notice that the structures in Part oc agree with those of the conventional VSC. Our prime concern in this part is the reduction of hitting time; hence high control gain is desired. On the other hand, the design of control law in Part fl and Part ),, i.e. the sliding phase $1S2 < 0 , is to be based on the purpose of eliminating the chattering, whilst retaining good robustness against disturbances and parameter variations. In Part fl and ),, a low-speed-changing structure will be established to reduce switching frequency and the highfrequency unmodelled plant dynamics is thus ignored. As seen from Fig. 1, the low-speed-changing structure is established if the following statements hold: Part fl: If the RP hits S 1 = 0 from S1S2>0 into S1S2<0 , the state trajectory gets near to $2 = 0 and gets far from S~ = 0. AUTO 2B:6-I 1209 Part y: If the RP hits $ 2 = 0 from S~$2>0 into S1S2<0 , the state trajectory gets near to St = 0 and gets far from , ~ = 0 . Combining the above results, it is of interest to observe that due to the addition of another switching surface, MVSC results in a quite small switching frequency"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003839_j.amc.2005.11.048-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003839_j.amc.2005.11.048-Figure1-1.png",
+ "caption": "Fig. 1. Hemispherical bearing model of synovial knee joint.",
+ "texts": [
+ " The introduction of g is due to polar additives in the non-polar lubricant, the ratio g/l has the dimension of length squared and hence characterizes the material length of the fluid. The flow problems discussed by Stokes indicate the significant effects of couple stresses and give hints for measuring various material constants and describe the influence of size effects associated with couple-stress fluid that is not present in non-polar cases. The physical configuration of the problem is shown in Fig. 1. The simulation of the squeeze-film behaviour of a human joint deals with the compression of thin poroelastic surface-a thin layer of fluid over another thin layer of poroelastic material. The articulation of joint is modeled as the case of a upper rough non-spinning spherical rotor (poroelastic cartilage) approaching the lower rough poroelastic hemispherical bearing normally with constant velocity dH/dt. Lubricant in the joint cavity is assumed as Stokes couple-stress fluid. The film thickness is made up of two parts H \u00bc h\u00f0t\u00de \u00fe hs\u00f0x; z; n\u00de; \u00f02:3\u00de where h(t) = Dr(1 + ecosh) represents the nominal smooth part of the film geometry while hs is part due to the surface asperities measured from the nominal level and is a randomly varying quantity of zero mean, n is an index parameter determining a definite roughness structure, e(=e 0 /Dr) is the eccentricity ratio, e 0 is the eccentricity, Dr(=Ro Ri) is radial clearance and h = x/R"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.26-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.26-1.png",
+ "caption": "Figure 4.26. Motion of a parti~le at the tip of an oscillating fan blade.",
+ "texts": [
+ "80f) The three cases studied here demonstrate that the relations ( 4.46) and ( 4.48) for the velocity and acceleration of a material point referred to a moving frame contain all of the basic equations (1.8), (1.10), (2.27), and (2.30) studied earlier in Chapters 1 and 2. However, in this example, the origin of the moving frame was fixed in the preferred framt:. We turn now to a similar example in which this is not the case. D 288 Chapter 4 Example 4.17. Application to the Motion of an Oscillating Fan Blade. The blade of an oscillating fan shown in Fig. 4.26 spins about a horizontal shaft of length I with a constant, counterclockwise angular speed w 2 \u2022 The fan assembly oscillates about a vertical axis with a variable speed w 1 = w cos pt, where p is the constant frequency of the fan oscillations and w is the maximum angular speed. Find in the ground frame 0 = { F; Ik} the total velocity of a point P at the tip of a blade two ways: (i) referred to the frame 1 = { 0; ik} imbedded in the motor housing, and ( ii) referred to frame 2 = { 0; i/.,} fixed in the blade. What is the total angular acceleraton of the blade for these cases? Solution of (i). In this problem, the particle P is moving relative to the oscillating motor housing frame 1 shown in Fig. 4.26; therefore, we shall employ ( 4.46) to find its absolute velocity. With this objective in mind, we now determine the required terms. The position vector of P in the motor frame 1 is given by x = a( cos 1,6 j + sin 1,6 k ). ( 4.81a) Therefore, the relative velocity of P in frame 1 is (4.81b) in which w 2 = /> is the constant angular speed of the blade in the motor frame. The total angular velocity of the motor frame relative to the ground frame 0 = { F; Ik} is given as Hence, with the aid of (4.81a), we obtain ro1 x x = -aw 1 cos 1,6 i",
+ " Since 0 is a point of a rigid body having the angular velocity ro 1 about a fixed base point at F, its velocity may be found by use of (2.27). Thus, ( 4.81e) Notice that the same result may be gotten by differentiation of B in frame 1; namely, v0 =B=/rofxi=w 1 /j. Substitution of (4.81b), (4.81d), and (4.81e) into (4.46) yields the solution. Thus, the absolute velocity of P referred to the motor frame 1 is v P = -aw 1 cos \u00a2J i + (w 1l- aw 2 sin \u00a2J) j + aw 2 cos \u00a2J k, ( 4.81f) wherein we recall that w1 = w cos pt. Solution of (ii). This problem requires that the motion of P be referred to the blade frame 2 = { 0; i~} shown in Fig. 4.26. Since there is no motion of P relative to the blade frame, (4.46) shows that the velocity is determined by the rigid body formula (2.27): (4.82a) The total angular velocity of the blade is given by = w2 i' + w 1(sin \u00a2J j' +cos \u00a2J k'). (4.82b) Hence, using the position vector x = aj' in frame 2, we get (4.82c) The velocity of the base point 0 is found from tht! first equation in (4.81e) in which B=li'. Thus, referred to the blade frame 2, we have v0 = /ro 1 xi'= lw 1(cos \u00a2J j'- sin \u00a2J k'). (4.82d) Substitution of ( 4",
+ " At the same time, the yoke is rotating about the axis of its supporting rod with a constant angular velocity ro 1 , as 344 Chapter 4 indicated. Find the absolute velocity and acceleration of a point P on the rim of the disk two ways: (i) referred to a frame fixed in the rotating yoke rod, and (ii) referred to a frame fixed in the spinning disk. \\ Problem 4.90. 4.91. The motion of an oscillating fan blade is described in Example 4.17. Use the data assigned in the example, and apply the two methods described there to find in the ground frame 0 = { F; Ik} the total acceleration of the blade point P. See Fig. 4.26. 4.92. A motor-driven gear G of radius a turns, as shown, with a constant angular speed w 1 about a honzontal axle fixea m a table T that concurrently rotates With a constant angular speed w 2 about a vertical axis fixed in the machine structure S. The center of G is at a distance b from the center 0 of the table. Find the total velocity and acceleration of the rim pomt P on G referred to (i) a reference frame fixea in Tat the center of G and (ii) a frame fixed in G. Problem 4.92. 4.93. A gear G of radius a rolls, as shown, on a rack gear R cut in a table T that turns about its normal axis with a constant angular speed w",
+ " Find the absolute acceleration of P referred to 1/J, and thereby derive two equations that may be used to determine x(t) and N(t) as functions oft. The solution of such equations is investigated in Chap ter 6. Problem 4.115. 4.116. (a) Apply the vector component transformation law (3.107) to derive (4.81f) from (4.82e) in Example 4.17. (b) Use the assigned data to derive from (4.81f) the absolute acceleration of the blade point referred to the motor frame 1. Apply the transformation law to determine from this result the absolute acceleration of P referred to the blade frame 2. See Fig. 4.26. 4.117. Begin with the vector equation (4.8) and prove, conversely, that the time rate of change of the Euler rotation tensor is given by (4.106a). Motion Referred to a Moving Reference Frame and Relative Motion 351 4.118. (a) Let T(t) be a tensor in a preferred frame cP but referred to a moving frame >e2 or e1<3.0.co;2-q-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001993_(sici)1521-3773(20000303)39:5<960::aid-anie960>3.0.co;2-q-Figure3-1.png",
+ "caption": "Figure 3. Illustration of the proposed mechanism for the reversible variations in PLGA helix rod orientation upon adsorption and desorption of guest helices and for the electron mediation function of the ferrocenyl moiety on gold substrates: a) pure monolayer II ; b) monolayer II complexed with PLGA-Fc-N; and c) monolayer II complexed with PLGA-Fc-C.",
+ "texts": [
+ " From the value of the ratio D, the tilting angle of the helices is calculated to be 258 (Table 1), which is significantly enhanced in the perpendicular orientation of helical rods, compared with the 518 tilt found before complexation. This result suggests that by complexation of monolayer II with the PLGA-Fc-N helix, a monolayer in a head-to-tail antiparallel orientation, which is energetically more favorable, is spontaneously formed, and consequently achieves a nearly perpendicular helix orientation. This effect is shown schematically in Figure 3 a and 3 b. When this complexed monolayer was treated with water at pH 9.0, the PLGA segments underwent a conformational change from a helix to random coil, then the monolayer released the guest PLGA-Fc-N into the bulk aqueous phase because of the loss of the helix macrodipole. An RA-FTIR spectrum of the monolayer after the pH-induced desorption of PLGA-Fc-N is similar to the original monolayer (Figure 2 d and 2 b), and consequently the tilting angle returns to the original value of monolayer II (Table 1)",
+ " This electrode, when the scan rate was varied at a constant concentration of [Fe(CN)6]4\u00ff (3 mm), yields a linear i versus v1/2 plot, to show the catalyzed reaction is sufficiently fast such that the process is controlled by [Fe(CN)6]4\u00ff diffusion.[28] From these results, it can be assumed that the immobilized ferrocenyl moiety facing the electrode surface behaves successfully as an electrontransfer mediator and the direction of electron transfer must be vectorial as schematically illustrated in Figure 3. To further support this hypothesis, the dependence on the [Fe(CN)6]4\u00ff concentration was examined under conditions similar to those in Figure 4 c (data not shown). The oxidation peak of the ferrocenyl moiety grew upon increasing the concentration of [Fe(CN)6]4\u00ff, as expected for a mediated process.[29] In conclusion, the orientation of helix rods and the precise location of a redox moiety in self-assembled monolayers have been demonstrated to be controlled through the helix \u00b1 helix macrodipole interaction"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001305_0924-0136(94)01333-v-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001305_0924-0136(94)01333-v-Figure3-1.png",
+ "caption": "Fig. 3. Depending on which side of the rectangular doubly-curved panel in Fig. 1 is used in the approximation, different values of 22 are obtained.",
+ "texts": [
+ " Asnafi / Journal of Materials Processing Technology 49 (1995) 13-31 15 and ~2 = [ 1 2 ( 1 - v2)] 1/2 ~2 ( R ) , (5) where R is the radius of the sphere, P is the concentrated load at the apex, E is Young's modulus, t is the shell thickness, v is Poisson's ratio and ~ is the angle between the centre and the edge of the sphere. Furthermore in this figure, ~5 is the deflection at the apex. Note that 22 in Eq. (5) and Fig. 2 is a measure of how large the shell segment is! The greater the value of ~, the larger is the sphere segment. a spherical shell. Depending on which side of the rectangle is used in the approximation, different values of ~2 are obtained: see Fig. 3 and compare it with Fig. 1! Combining Eqs. (2), (3) and (4) p . ~ P - 2 ~ E t a (6) The maximum load that will be used in the stiffness tests is 125 N. Substituting into Eq. (6) this value, the nominal values of R1 and R2 (Fig. 1), E = 20.104 N/mm 2 and t = 0.7 mm, P* = 0.334. which gives the encircled zone in Fig. 2, applicable in the present approximated case. Knowing the different values of 2 2 (Fig. 3), the applicable load~leflect ion zone in the present approximated case, (Fig. 2), and the shape of the load-deflect ion curve in this zone, it is assumed that over this interval and for the present panel p , = C(6/t) m (7) N. Asnafi / Journal of Materials Processing Technology 49 (1995) 13-31 17 in which C and m are different constants. Combining Eqs. (4) and (7), P = C2rtE t3(f/t)m x/~ll R 2 In this study, Eqs. (1) and (8) will be examined. (8) is shown in Fig. 4. T~ arises from the resistance of the outer region to plastic deformation, if the outer region deforms, material being drawn inwards"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002068_bf00052455-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002068_bf00052455-FigureI-1.png",
+ "caption": "Fig. I. Typical diesel-engine driveline system and forces in a mesh of gears.",
+ "texts": [],
+ "surrounding_texts": [
+ "Machines and mechanisms are characterized by rigid or elastic bodies interconnected in such a way that certain functions of the machines can be realized. Couplings in machines are never ideal but may have backlashes or some properties which lead to stick-slip phenomena. Under certain circumstances backlashes generate a dynamical load problem if the corresponding couplings are exposed to loads with a time-variant character. A typical example can be found in gear systems of diesel engines, which usually must be designed with large backlashes due to the operating temperature range of such engines, and which are highly loaded with the oscillating torques of the injection pump shafts and of the camshafts. Therefore, the power transmission from the crankshaft to the camshaft and the injection pump shaft takes place discontinuously by an impulsive hammering process in all transmission elements. Figure 1 indicates how the process works. A typical gear unit contains several meshes with backlashes, in the case shown two meshes with backlashes between crankshaft and injection pump shaft and three meshes with backlashes between crankshaft and camshaft. Due to periodical excitations mainly from the injection pumps and subordinately from the crankshaft and the camshaft the tooth flanks separate generating a free flight period within the backlash which is interrupted by impacts with subsequent penetration. The driving flank (working flank) usually receives more impacts than the nonworking flank (Figure 1). Additionally, in all other backlashes of the gear unit similar processes take place, where the state and the impacts in one mesh with backlash influences considerably the state in all other meshes. This behavior must be regarded by the mathematical model. As a definition we use the work \"hammering\" for separation processes within backlashes where high loads cause large impact forces with penetration. Motion within backlashes without loads is called \"rattling\". This represents a noise problem without load problems. It will not be considered here. As a rule, such vibrations may be periodic, quasi-periodic or chaotic with a tendency to chaos for large systems. Considering the driveline-gear-unit as a multibody system with f degrees of freedom and with np backlashes in the gear meshes we model the backlash properties by a nonlinear force characteristic with small forces within the backlash and a linear force law in the case of contact of the flanks. The event of a contact is determined by an evaluation of the relative distance in each backlash, which serves as an indicator function. The indicator function for leaving the contact, i.e. flank separation, is given with the normal force in the point of contact, which changes sign in the case of flank separation. These unsteady points (switching points) must be evaluated very carefully to achieve reproduceable results. The time series of impact forces will be reduced to load distributions in a last step. They might serve as a basis for life time estimates. Dynamical systems with unsteady behavior have been subject to increasing investigations during the last years. With regard to impulsive processes the bouncing ball problem is a very old and famous one [10]. With the progress of nonlinear dynamics in the last two decades a series of publications came out on problems of impact phenomena, in all cases confined to systems with two or three degrees of freedom only [6, 8, 13, 14, 21, 22, 29, 30]. Applications to technical problems were rare and mainly restricted to gear research contributions [23, 24, 26, 27, 28]. The first activities on impulsive processes at the author's institute started in 1982 and lead to a series of contributions on rattling and hammering processes in gear boxes and in drivelines. The fundamental starting point was a general theoretical approach to mechanical systems with unsteady transitions in 1984 [ 15], which was very quickly extended to rattling applications [ 11, 12, 16, 17]. The dissertation [9] deepened the rattling theory and compared one-stage rattling with laboratory tests. From the very beginning all theoretical research focused on general mechanical systems with an arbitrary number of degrees of freedom and with an arbitrary number of backlashes. Application fields are drivelines of large diesel engines, which due to a large temperature operating range usually are designed with large backlashes [1, 20]. The dissertation [20] represents the newest state of research and will be the basis of this paper. The plenary lecture [19] gives a survey on dynamical systems with time-varying or unsteady structures."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002572_robot.1996.506595-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002572_robot.1996.506595-Figure5-1.png",
+ "caption": "Fig. 5 Simulation result with y = 0 in eq.(48)",
+ "texts": [
+ " The path for the case when the position and the orientation of the object are fixed has 0.0549 as the value of S. In the case of Fig.3, total value of variations of joint variables becomes smaller by moving the manipulator-A. From this result the meaning of the pseudo inverse is understood. Fig.4 shows the result considering obstacle avoidance. The value of S is 0.0198 for this case. The obstacle is avoided by using the pokential function in eq.(47). Next, 3-dimensional example is considered. Fig.5 shows the simulation result with y = 0 in eq.(48) and Fig.6 shows the result with collision avoidance. 7 Conclusions Our purpose of this paper was to propose an algorithm to plan the cooperative collision free motion for two manipulators system. In general, the two manipulators system has redundancy. By using the redundant degrees of freedom, the desired cooperative motion which executes the specified task can be planned. The potential function method is used for collision avoidance. Numerical examples show the effectiveness of the proposed method"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002263_6.2003-5349-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002263_6.2003-5349-Figure5-1.png",
+ "caption": "Fig. 5 Bell-Hiller system with angular displacements",
+ "texts": [
+ " The flybar and main rotor flapping motions are governed by the same effects, namely the gyroscopic moments due the helicopter roll and pitch rates. But unlike the main rotor, the flybar is not responsible for providing lift or maneuvering ability. Thus, it can be designed to have a slower response and provide the desired stabilization effect. The flybar response can be optimized by varying the ratio of aerodynamic to inertial loads on the paddles. Changing the shape, weight or distance between the paddles are all straightforward ways of tailoring the system. The notation used to describe the Bell-Hiller system is presented in Fig. 5. Due to the Bell-Hiller system, the flybar flapping and blade pitching angles are physically constrained to satisfy [ \u03b80 (\u03c8) \u03b81 (\u03c8) ] = l\u03b4 l\u03b8 l1 l1 + l2\ufe38 \ufe37\ufe37 \ufe38 c1 [ (l4 \u2212 h\u03b4 (\u03c8)) /l\u03b4 \u03b41 (\u03c8) ] + l\u03b2f l\u03b8 l2 l1 + l2\ufe38 \ufe37\ufe37 \ufe38 c2 [ 0 \u03b2f ( \u03c8 + \u03c0 2 ) ] , (13) where \u03b41 is the differential pitch input, given by \u03b41(\u03c8) = \u03b41c cos(\u03c8) + \u03b41s sin(\u03c8). (14) 5 American Institute of Aeronautics and Astronautics Likewise, \u03b2f has no coning mode, since the flybar, as a teetering rotor, can only describe see-saw flapping motions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002564_robot.1988.12089-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002564_robot.1988.12089-Figure2-1.png",
+ "caption": "Figure 2: Schematic of University of Minnesota Arm",
+ "texts": [
+ " Thls is t r u e because t h e l inks h a v e s teady d e f l e c t i o n due t o cons tan t g r a v i t y e f f e c t . Thls w i l l g l v e b e t t e r accu racy and r e p e a t a b i l i t y f o r f lne manlpulat lon tasks. IV. A s d e p l c t e d In F lgure 3, t h e a r c h i t e c t u r e o f t h l s r o b o t a l l o w s f o r a \" l a r g e \" workspace. The h o r l z o n t a l workspace o f t h l s r o b o t Is qu i te a t t r a c t i v e f r o m t h e s t a n d p o l n t o f manu fac tu r lng tasks such a s assembly and debur r l ng . Figure 2 shows t h e schernatlc dlagram o f t h e Unlvers l ty o f M i n n e s o t a d i r e c t d r l v e arm. The arm h a s t h r e e degrees o f f reedom, a l l o f whlch a re a r t l c u l a t e d d r l v e Jo lnts . M o t o r 1 p o w e r s t h e sys tem a b o u t a v e r t l c a l E X I S . M o t o r 2 p l tches t h e en t l re four-bar- t lnkage wh i l e m o t o r 3 Is used t o p o w e r t h e four-bar- l lnkage. Llnk 2 Is d i r e c t l y connec ted t o t h e s h a f t o f m o t o r 2. Flgure 3 shows t h e t o p v lew and slde v lew o f t h e r o b o t "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000909_027836499901800506-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000909_027836499901800506-Figure3-1.png",
+ "caption": "Fig. 3. The grasp on a circular object with two fingers (left); and the grasp index fmin for different symmetrical grasp configurations (amax = 100 N).",
+ "texts": [
+ " A similar procedure may be followed for the other subdomains of the disturbance actions as present in eq. (5). Also, the friction coefficient of the finger-to-object contact for any external force that has a unit value and is not directed along the axes of the reference system is minimized via the solution to the optimization problem in eq. (4). For a generic external disturbance torque of a unit value (eq. (6)), the friction coefficient at the contact points is directly minimized in the optimization problem (eq. (4)) with h = 5, 6. Figure 3 reports the results obtained for a two-finger grasp of a circular object. In this example, the greatest normal force amax is equal to 100 N, and the optimization problem (eq. (4)) is solved for the different symmetrical grasp configurations detected by the angle \u03b1. The objective function fmin, i.e., the minimum-friction coefficient, is observed to decrease as the angle \u03b1 decreases, until it reaches the lowest value of fmin = 0.005, with \u03b1 = 0. Thus, when the two contact points are diagonally opposite to each other, the lowest friction coefficient is required to balance all the possible disturbance forces and torques",
+ " Once reducing the friction coefficient required to balance the object has been defined as the objective for contact stability, the term fmin may be taken as an index of grasp quality. In particular, when two grasp configurations are compared, the one where the lowest value of fmin is obtained will on at SETON HALL UNIV on April 2, 2015ijr.sagepub.comDownloaded from average require a lower friction coefficient to balance the external forces acting on the object, thus ensuring contact with no slipping. Then, for the example in Figure 3, the optimal grasp configuration is attained when \u03b1 = 0. As in the previous example, Figure 4 reports the results obtained for a three-contact-point grasp of a circular object. Symmetrical grasps are considered for different values of the angle \u03b1, and the objective function fmin reaches its lowest value where \u03b1 = 30\u25e6. This means that the optimal grasp is achieved when the three fingers are placed at the vertices of an equilateral triangle. It then suffices to minimize fmin as the location of the contact points changes, in order to determine the optimal grip points"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002333_a:1025991618087-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002333_a:1025991618087-Figure1-1.png",
+ "caption": "Figure 1. The multibody model of trampolinist.",
+ "texts": [
+ " To meet the requirements of the present study, and intending to build the mathematical model as complex as necessary and as simple as possible, the following limitations have been assumed: \u2022 Planar motion is considered, which limits our analysis to front and back somersaults without twisting. \u2022 The trampolinist is modeled as a multi-rigid-body system with revolute joints, and the effects of muscle forces at the joints are modeled as control torques (many other musculo-skeletal models use similar assumptions, see e.g. [8\u2013 10]). Synchronous motions of two legs and two arms are assumed. \u2022 The trampoline bed is treated as weightless canvas with known stiffness and damping characteristics. The multibody model of trampolinist used for this study is seen in Figure 1. It consists of seven rigid segments, and the number of DOF of the system is nine. The nine generalized coordinates that describe the position of the system with respect to the inertial reference frame xy are q = [xH yH \u03d51 \u03d52 \u03d53 \u03d54 \u03d55 \u03d56 \u03d57]T , where xH and yH are the hip coordinates, and the angular coordinates \u03d5i (i = 1, . . . , 7) are measured from the vertical direction. All the entries of q are thus absolute coordinates. The six control torques that model the moments of muscle forces at the joints are \u03c4 = [\u03c41 \u03c42 \u03c43 \u03c44 \u03c45 \u03c46]T "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001277_s0997-7538(00)00139-x-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001277_s0997-7538(00)00139-x-Figure5-1.png",
+ "caption": "Figure 5. Comparison of journal centre trajectories for unbalanced rigid shaft (\u03b5b = 0.1).",
+ "texts": [],
+ "surrounding_texts": [
+ "The nonlinear dynamic analysis, described in the preceding sections, has been incorporated into MS-Fortran computer programs. In order to validate the results obtained from the optimised short bearing theory, a separate 2-D finite difference program was written to simulate the transient response for three cases of journal bearings operating in laminar and turbulent flow regimes. For 2-D finite difference analysis, which in this paper will be referred to as the exact solution, a grid size of (61\u00d7 21) nodes is used in \u03b8 and z directions, respectively. The number of nodes is chosen in order to ensure accurate results with minimum CPU time. The normalized Reynolds equation (8) is solved by applying the successive over relaxations scheme for each time step, so that a large amount of computation time is required to obtain the journal centre locii. Whereas, in the optimised short bearing analysis, the fluid-film discretization is only carried out in the circumferential direction \u03b8 in order to solve the normalized equation (18), and then the computation time required is considerably less than in the 2-D finite difference analysis. Thus, the optimised short bearing solution has an advantage of reducing a computation time required for the prediction of nonlinear journal centre trajectories. For all the calculations, the following conditions are used: \u2013 the initial position of the journal centre is kept constant for each case and is situated near the geometric centre of bearing (X0 = 0.01, Y0 = 0), \u2013 the initial velocity of the journal centre is assumed to be zero, \u2013 the dimensionless time increment 1\u03c4 used in the calculations was 2\u03c0 200 , \u2013 the effect of the dynamic dissipation, due to the orbital motion of the shaft, on the lubricant viscosity value is not taken into account, \u2013 the convergence criterion for the pressure is kept constant: the relative pressure deviation is 10\u22125, \u2013 for both methods, the over-relaxation coefficient optimum value is equal to 1.80. However, preliminary tests have shown that the change of the initial position of the journal centre and of the time increment do not affect the results. Example 1: To compare the results produced by the developed programs with those obtained experimentally, the test data published by Hashimoto and Wada (1990) were used. The rotating shaft was supported horizontally by two identical bearings with full circumferential grooves at the mid-plane sections as shown in figure 3. Therefore, the rotating shaft was essentially supported on four identical short journal bearings (L/D = 0.5). The weight of the rotating shaft was 108 N. Then, the load applied per bearing was about 27 N. The only applied load, in this case, is the static vertical weight of the rigid rotor. The journal bearing characteristics and the operating conditions are reported in table I. The calculations are made under various rotational shaft speeds and unbalance eccentricities. The nonlinear journal centre trajectories are examined for two values of rotational shaft speed N = 3000 and 6000 rpm. The mean Reynolds numbers for each case are Rm = 2750 and 5500. The unbalance eccentricity ratio \u03b5b varies from 0 to 0.20 which correspond to eb = 0 and eb = 50\u00d7 10\u22126 m, respectively. Figures 4 to 6 show the journal centre trajectories within the rigid bearing taking into account the inertia effects. The solid lines indicate the results by 2D-finite difference method and the dashed lines the results by the optimised short bearing solution for a rigid rotor with and without unbalance forces. To take into account the film rupture, the half-Sommerfeld or Gumbel boundary condition was used in the calculations. It should be noted that only the final form of journal centre orbits are presented in figures 5(a) and 6(a), i.e., the results corresponding to the transient numerical effect due to the initial conditions are omitted. It follows from these figures that: \u2013 the general similarity of the final form of nonlinear journal centre trajectories with those given in the above reference is obvious, \u2013 for both methods, the results obtained agree very well as can be seen by comparing the transient responses of a journal-bearing system. Example 2: To further validate the results obtained from the optimised short bearing theory, an another example from the Abdul-Wahed research work (1982) were simulated. The effect of cavitation in the divergent zone of the film is taken into account using Swift\u2013Stieber or Reynolds boundary conditions. These conditions are satisfied by using the Christopherson algorithm (Christopherson, 1941). The details of bearing geometry and operating conditions are given in table II. As shown in figure 1, the journal bearing system is supplied in lubricant through an axial groove which is located on the static load line. The lubricant viscosity average value is obtained from the application of a simplified approach based on the concept of effective or mean temperature by assuming that all the heat has been evacuated by the lubricant. An iterative procedure is used to seek the average temperature value for static equilibrium conditions. For reasonable unbalance eccentricities (\u03b5b \u227a 0.4), it is generally sufficient to carry out the calculation of the mean temperature for the same static equilibrium conditions since the dissipated energy due to the orbital motion of the journal centre with respect to the whole energy is small. Table III shows that the peak-to-peak displacement amplitudes 1x and 1y, the minimum film thickness hmin and the maximum bearing dynamic transmissibility FDmax calculated by using the optimised short bearing theory compare well with those given by Abdul-Wahed (1982). Figures 7 and 8 illustrate the predicted static pressure profile corresponding to the laminar static equilibrium position defined by the coordinates (x0, y0)= (154.55 \u00b5m, 162.39 \u00b5m). In figure 7, the pressure profile at the mid-plane section of bearing obtained by the suggested approach (solid curve) is compared to that calculated by the classic short bearing theory (dashed curve). It is indicated that the short bearing approximation (Ocvirk solution) predicts a higher value of maximum pressure compared to the optimised short bearing solution, and the difference increases with an increase in the static eccentricity ratio. Figure 8 shows a comparison between the pressure profiles at the central plane of bearing calculated by using the optimised short bearing solution (dashed lines) and 2-D finite difference (solid lines). It is seen that the peak pressure predicted by the proposed approach is over-estimated by about 2% which is acceptable. Example 3: In this case, the bearing characteristics and operating conditions are similar to those given in table II. The principle differences between these operating conditions and the ones used previously are the rotating shaft speed which is equal to 6000 rpm instead of 3000 rpm and the aspect ratio L/D is equal to 1 instead of 0.64. The results of the peak-to-peak displacement amplitudes of the journal centre motion, the minimum film thickness and the maximum bearing dynamic transmissibility obtained by using optimised short bearing solution are compared to the ones by 2-D finite difference technique in table IV. It is seen that the discrepancies are 0.1 percent on the displacement amplitude, 9 percent on the minimum film thickness and 1.8 percent on the dynamic transmissibility coefficient. Although the aspect ratio L/D is equal to 1, the optimised short bearing theory permits to obtain very good results using both the laminar and turbulent flow regimes. As shown in table IV, the optimised short bearing solution requires 20.92 seconds of CPU time on a Personal Computer (Pentium with a 200 Mhz processor) to complete 24 revolutions of the shaft. By comparison, the 2-D finite difference analysis took an estimated 1022 seconds (17 minutes and 2 seconds) of computation time (about 50 times more than the new analysis). Thus, the main objective of optimised short bearing analysis, i.e., to reduce the computing costs to a reasonable level, has certainly been met."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003024_1.2103093-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003024_1.2103093-Figure6-1.png",
+ "caption": "Fig. 6 Relative pressure \u201ePa\u2026 contours on the periodic plane in the backing ring corner region",
+ "texts": [
+ "40 mm Bristle diameter D 0.076 mm Young\u2019s modulus E 2.25 1011 N/m2 Minimum initial clearance between bristles 0.0076 mm Number of bristle elements K 20 Initial rotor interference Zrotor 0.00 mm Pressure load P 1.00 bar rapid, and the aerodynamic forces changed by no more than about Transactions of the ASME ?url=/data/journals/jotuei/28726/ on 05/06/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F 10% from the initial undisturbed geometry calculation. As shown by the pressure contours in Fig. 6 and velocity vectors in Fig. 7, the strongest flow occurs near the backing ring edge. In this region, there is a strong flow directed down the backing plate and along the bristles. This is due to the comparatively weak resistance to flow in this direction compared to that normal to the bristles. Not surprisingly, the peak aerodynamic forces occur on the downstream bristle near the backing ring edge. The strong velocities near the backing ring corner in Fig. 7 may explain the negative relative pressures in Fig. 6. Note that assuming a pressure load of 105 Pa distributed evenly over the five bristles in the region overhanging the backing ring would give a uniform aerodynamic force on each bristle of 1.52 N/m. It is interesting to note that values are slightly greater than this in Fig. 5. A thorough investigation of this effect would require study of the influence of outlet boundary conditions including their influ- Journal of Turbomachinery rom: http://turbomachinery.asmedigitalcollection.asme.org/pdfaccess"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002417_0278364903022002001-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002417_0278364903022002001-Figure3-1.png",
+ "caption": "Fig. 3. Car-like steering using linear and circular arcs.",
+ "texts": [
+ " In this paper, we focus on the problem of time optimal paths for point-to-point locomotion for a steered car, but more complex motions, including obstacle avoidance, or task-related motion planning can also be incorporated. First, we recall the results of Dubins (1957) for kinematic mobile robots. It was shown that the time optimal path for a car steering in SE(2) with limits on the turning radius is given by two circular arcs\u2014one arc tangent to each of the initial and final headings\u2014connected by a straight-line segment (see Figure 3). In this section we utilize these paths as the backbone for steering dynamic non-holonomic systems. In order to make the abstraction shown in Figure 1 from the dynamic system to the approximate dynamic system (and hence further to the kinematic, car-like system) work, the approximation must lead to a system that is \u201csteerable\u201d in the sense of a wheeled vehicle. We characterize as steerable any system for which we can use the shape variables to generate body velocities (cf. eq. (1)) of the form \u03be = g\u22121g\u0307 = (v, 0, v/R)T , where v is the forward velocity, and Rmin < R < \u221e is a control variable representing the turning radius (andRmin a turning radius constraint)",
+ " Since we are performing feedback control on a system using periodic gaits, we sample the robot position by averaging the center of mass position and velocity over one gait cycle. This places a theoretical (Nyquist) limit on the controller dynamics of FS/2. In practice, for a 1 Hz drive gait, controller responses of under 5 s are likely not achievable. We use a feedforward law based on the (curvature of the) path generated by the kinematic motion planner. In addition to this, we note that, since the steering is only approximate, the addition of a feedback term is desirable. PROPOSITION 2. A steered cart of the form of Figure 3 can be stabilized by a proportional feedback control law of the form \u03b8\u0307 (t) = k\u03b8(\u03b8d(t) \u2212 \u03b8(t)) \u2212 kd(d) for k\u03b8 > 0 and kd < 0. Proof. If we define d as the signed, perpendicular distance to the desired trajectory (with d negative when the desired trajectory is to the right of the actual trajectory), the motion of a steerable cart (see Figure 3) is described by d\u0307 = v sin(\u03b8d(t) \u2212 \u03b8(t)). Using a proportional feedback control law for the cart of the form \u03b8\u0307 (t) = k\u03b8(\u03b8d(t) \u2212 \u03b8(t)) \u2212 kd(d) it is straightforward to show that the linearized equations of motion can be easily stabilized about a straight path. The characteristic equation for the linearized system is s2 + k\u03b8s \u2212 vkd = 0. The condition for stability of this system therefore is k\u03b8 > 0 and kd < 0 which matches our intuition about steering. Figure 8 shows the path of the eel tracking an oval-shaped path (in simulation) that integrates both circular and straightline segments"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002544_ac00217a013-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002544_ac00217a013-Figure1-1.png",
+ "caption": "Figure 1. Flow cell construction: (1) optical fiber, (2) fiber mounting cylinder, (3) front plate, (4) solution inlet channel, (5) solution outlet channel, (6) front window, (7) slotted gasket, (8) thin film Ca(I1) sensor, (9) diffuse white reflector, (10) back plate.",
+ "texts": [
+ " The films scatter light analogously to the mats commonly employed as references for diffuse reflection spectroscopy. Immobilization was accomplished by immersing a film into an aqueous 0.1 mM calcichrome solution for 24 h at 25 \"C. Under these conditions, the concentration of immobilized calcichrome was -6 mM (1.2 mmol/g of dry film). This value was determined by the optical quantitation of the difference in the amount of colorimetric reagent in solution before and after immobilization. The thickness of an immersed membrane was -800 fim. Flow Cell. The optical sensor and flow cell are shown in Figure 1. The incident light was carried to the cell through 400-fimdiameter optical fibers (Ensign-Bickford Optics Co., Avon, CT). The fiber diameter with cladding is -730 fim. Optical fibers also collected and transmitted the diffusely reflected light to the entrance slit of a monochromator. The optical fiber bundle consisted of 10 fibers, which were arranged in a vertical orientation, with half used to transmit the incident light to the thin film and half used to transmit the diffusely reflected light to the entrance slit of a monochromator"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003241_tasc.2004.830317-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003241_tasc.2004.830317-Figure3-1.png",
+ "caption": "Fig. 3. HTS induction motor coupled with the electrodynamometer.",
+ "texts": [
+ " To accommodate the flat HTS tape, shape of the slot of the HTS rotor should be different from that of the conventional motor. Cross section of the HTS rotor is given in Fig. 1. Figs. 1(a) and (b) show the cross section of straight part and the end part, respectively. Outer diameter and inner diameter of the HTS rotor were 78 mm and 22 mm, respectively. Fig. 2 shows the cage rotor of the conventional and the HTS motor. HTS tapes for the short bars are soldered to the HTS tapes for the short rings. Electrodynamometer was coupled to the motor to apply the load. Fig. 3 shows the test system, where the HTS motor, the electrodynamometer and the cryostat are shown. Electro-dynamometer was placed on the top flange of the cryostat. To simplify the cooling system of the HTS motor, whole motor including stator and rotor was put in the cryostat and immersed in liquid nitrogen. Total height of the test system was 1,321 mm. Speed-torque curve of the HTS motor was obtained by using the equivalent circuit method. To get the parameter of equivalent circuit, no-load test and locked-rotor test have been carried out"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003008_1.1757488-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003008_1.1757488-Figure2-1.png",
+ "caption": "Fig. 2 Spherical inclusion in a plate. Distributions of virtual loop defects are shown on the plate surfaces.",
+ "texts": [
+ " As a result, prismatic dislocation loops, twist disclination loops, and radial disclination ~Somigliana dislocation! loops may be used as virtual defects in polar angle independent elastic problems of cylindrical symmetry. For defects with angle-dependent elastic fields, e.g., edge dislocations, one can utilize another set of virtual loops having the same angle dependence, e.g., glide dislocation loops, @9,11#. 4.1 Spherical Inclusion in a Plate and a Half-Space. Consider a spherical dilatating inclusion located in a plate of thickness t as shown in Fig. 2. The plastic distortion of the inclusion is bxx* 5byy* 5bzz* 5\u00ab*d(Vsph), where d(Vsph)5$0,r\u00b9Vsph 1,rPVsph%, Vsph is the area of the inclusion; and \u00ab*5DR/R characterizes the relative change of the inclusion radius. The latter may also be interpreted as the misfit strain characterizing crystal lattice mismatch between the inclusion and the surrounding matrix. Referring to the geometry and coordinate system shown in Fig. 2 and assuming that the elastic properties of the inclusion and surrounding matrix are the same, the total displacements `u j and elastic stresses `s i j of an inclusion in infinite media are, @21#: 412 \u00d5 Vol. 71, MAY 2004 rom: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/20 `ur ~ in!5 \u00ab*~11n!Rsph 3~12n! \u2022 r\u0303; `uw ~ in!50; `uz ~ in!5 \u00ab*~11n!Rsph 3~12n! \u2022~ z\u03032 h\u0303 !; `ur ~out!5 \u00ab*~11n!Rsph 3~12n! \u2022 r\u0303 ~ r\u030321~ z\u03032 h\u0303 !2!3/2 ; `uw ~out!50; `uz ~out!5 \u00ab*~11n!Rsph 3~12n! \u2022 z\u03032 h\u0303 ~ r\u030321~ z\u03032 h\u0303 ",
+ " On the free surface of the plate the following boundary conditions for the total stress field s i j5 `s i j1 is i j must hold: s jzu$z50 z5t %50, j5r ,w ,z . (21) Transactions of the ASME 16 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F The inclusion stresses `szz and `srz given by Eqs. ~20! contribute to the boundary conditions given in Eqs. ~21!. To satisfy the boundary conditions we assume that an additional field is i j is generated by the distributions of circular prismatic dislocation loops ~ensemble 1! and radial disclination loops ~ensemble 2!, placed on the free surfaces of the plate ~see Fig. 2!. These virtual rom: http://appliedmechanics.asmedigitalcollection.asme.org/ on 01/27/20 defects possess stress components szz and srz and a component swz vanishes. Rewriting Eqs. ~21! with the help of the fields of the virtual loops we obtain the integral equations with respect to unknown functions of loop distributions 12 f (a), 22 f (a) placed on the surface z50 and 11 f (a), 21 f (a) placed on the surface z 5t: `szz ~out!uz501E 0 ` 12 f ~a !\u202212szzuz50da1E 0 ` 11 f ~a !\u202211szzuz50da1E 0 ` 22 f ~a "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001511_978-1-4612-1416-8_9-Figure9.1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001511_978-1-4612-1416-8_9-Figure9.1-1.png",
+ "caption": "FIGURE 9.1. (a) Rotating planar pendulum joint; (b) Rotating universal pendulum joint. We consider a simple rotating pendulum suspended by either type of joint as depicted. The pendulum consists of a link of length e, which we assume to be massless and at the end of which are four equal masses symmetrically distributed as shown so that the moment of inertia of the pendulum is nonsingular.",
+ "texts": [
+ "1 (Rotating heavy chains) The global dynamics ofa heavy (hanging) chain undergoing forced rotation about a vertical axis will be crucially dependent on how the joints between the links of the chain constrain the possible relative motions of the links. This dependence has been explored in Baillieul and Levi [7]. Further insight into the global dynamical effects of relative motion constraints may be developed in terms of the curvatures defined above. Consider the two rotating pendulum systems in Figure 9.1. Both pendula undergo controlled rotations about the vertical axis. In Figure 9.1{a), the joint by which the pendulum is suspended is a single degree~of-freedom revolute joint, while in Figure 9.1{b), the link is sus pended by a (tWQ degree-of-freedom) universal joint. The respective Lagrangians are and L2(\u00a2, l{!, \u00a2, v,; e) = ~ [ (/2 cos2 l{! + a; (1 + sin2 l{!\u00bb) \u00a22 + (a; +12) v,2 + (/2 - a;) cos\u00a2 sin(2l{!) \u00a2e - (a 2 + 2/2) sin\u00a2 V, e + (a 2 cos2 \u00a2 cos2 l{! + (a: + 12) (sin2 \u00a2 + cos2 \u00a2 sin2 l{!) ] e2 + mgl cos \u00a2 cos l{!. 2 (Cf. Baillieul and Levi [7, Section 6], where we identify Ix = Iy = m(l2 + ;-), and I z = ma2.The corresponding controlled dynamics associated with L I and L2 respectively are ~ [m (a2 COS2 \u00a2 + [2 sin2\u00a2)iJ] = u dt 2 (z2 + a 2 2 ) \u00a2 + (a 2 _[2) sin\u00a2 cos\u00a2iJ2 + g[ sin\u00a2 = 0, and (in abbreviated form) d aL2 ---u dt aiJ - , (9"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001869_irds.2002.1043954-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001869_irds.2002.1043954-Figure7-1.png",
+ "caption": "Figure 7: Evolving tmjectory of a knot",
+ "texts": [],
+ "surrounding_texts": [
+ "the condition for initiating knot motion (relative sliding between the strands) and then the the trajectory of strand end points for the desired knot trajectory. The problems that we are addressing are:\n0 Given the geometry of the knot and f i c t i o n coeficient of the suture, determine the condition under which knot motion will commence.\n0 Given a desired knot placing trajectory, determine the trajectories of suture end points that would achieve this desired knot trajectory.\nAs the starting point of knot placement, we assume a simple knot is already developed by wrapping the loop strand around the post strand and by applying tension forces as shown in Figure 1.\n2.2 Sliding condition Moving the knot requires sliding the two strands relative to each other. To investigate the impending sliding condition, we need to have a static force balance model. The general model of a knotted suture is quite difficult due in part of the flexibility of the suture and complex contact geometry. In this paper, we use a simplified model based on the assumption of a two-point contact between the sutures, as shown in Figure 2. The freebody diagram is shown in Figure\n3. The impending sliding problem can now be stated as:\nGiven &, @2a, A, and A, determine the relationship between the angles 11flb11 ll@\"bII yi's and pi's, i=1,2, when the sliding motion is about to begin.\nDefine Zla = L, &a = L, Z1b = h, and IIFlaII l lFZa11 l l F l b I I\nZ2b = A ll&, and let Zn = e be the unit vec-\ntor along which the normal forces apply and Zt be the unit vector along which the frictiyn forces apply. When the knot is in equilibrium, F = 0, so\nFlaZia + F2aZ2a FlbZIb + F2b&b = 0. (1)\nThis equation has two unknown variables, F1b and F26, which can be uniquely solved in general. The condition of impending motion can be obtained from the free-body diagram of one strand as shown in Figure 4. The impending motion occurs when\n(FIaZla + F&b> . Zt = P(fian -k flbn). (2)\nFrom (2), it is possible to obtain the general sliding condition, but it is quite complicated. Since the desired knot trajectory lies in the normal direction to the tissue, we shall only consider the symmetric\nshown in Figure 5. At the equilibrium, the force and moment equations about p and p' are\nc=e(P = PI = ,927 7 = 71 = 7 2 , F1a = F2a), as\n(4) (5)",
+ "Coulomb\u2019s law states the sliding occurs when\nIt can be further simplified to\n(7) 1 1 tanp tany > 2P, ---\nwhich results in the following sliding condition\n(8) tany\n2p tany + 1 o < p < tan-\u2019( ).\nThis means that the sliding begins when the angle ,8 is sufficiently small to satisfy the inequality condition which depends on the coefficient of friction between the strands and y. Note that when the a p plied force is horizontal, i.e., p = 0, which means that the two leg strands have zero tension. When p is small, for a given tension requirement in the leg strands, the applied force Fla and F2a would be very large. Therefore, when the applied force is constrained (e.g., to avoid breaking the suture), there is a practical lower bound, @min, on p. To summarize, for the knot to move, the applied tension needs to lie in the (Pmin, p,] cone as shown in Figure 6.\n2.3 Trajectory of suture ends for placing a knot\nIf the suture is in tension, the knot motion can be determined from the end motion of the sutures due to the length invariant constraints. Let q be the current knot position and ple and be the current position of each end of strands. During motion, we assume\nthat the length of each strand is constant.\nWhen the suture ends move to new positions, the knot position q\u2019 can be obtained from the following length invariant constraint equations (which is imposed so that the strands remain in tension):\nI I d e - dII + IId -PloII = e1 IIPke - dII + IId - ~ 2 0 1 1 = ~2\n(11) (12)\nBy choosing the suture end position trajectories, we can shape the knot position trajectory. We focus on the case that the desired knot trajectory is a straight line normal to the tissue. This case can be achieved with only symmetric pulling. The problem then becomes finding p l e ( t ) to move the knot along p n ( t ) as shown in Figure 8. Let 6 denote the unit vector along the desired direction of knot motion, and s be the desired sliding rate. The angle y ( t ) and the\ndistance between pb and pn evolve according to",
+ "Due to the sliding condition, (&in 5 p(t) 5 pmU(t) = f(y(t),p)), the trajectory of the suture end to just start knot motion is\nple( t ) = plea + s(t)(cos(P(t))u + sin(p(t))v)* (16)\nExcessive tension at the tissue at pa and pb could damage the tissue. The optimal trajectory in the sense of minimizing the tension force in the leg strand can be obtained by using the minimum p(t) = &in\nple( t ) = plea + b ( t ) ~ + ( s t ) E . (17)\nFigure 9 compares the trajectories with p(t) =\nexerted by environment on the end-effector. In tension control where the motion is relatively slow, Fm can be neglected. The configuration-dependent static wrench due to gravity can be determined in real-time. Therefore, the wrench in the end-effector frame, Fe, can be easily calculated from the measured base wrench:\nPmaz(t) and P(t> = 0.\n3 Tension Regulation 3.1 Tension measurement Measuring tension applied to the suture in minimally invasive surgeries is difficult because of the limited mounting space and sterilization requirement. Strain gauge transducers have been widely used for force measurement, but it is undesirable in the minimally invasive surgical setting. The sensor is sensitive to the temperature variation, contact with tissues during surgeries may cause drift in the sensor output, and it must be sterilized in high temperature after each use. The disposal type of strain gauge sensors addresses sterilization but means high cost and time consuming calibration. In this research, the suture tension is measured through a force/torque sensor in the base of the surgical robot, as shown in Figure 10. This approach has the advantage that the sensor does not need to be sterilized and the force measurement (and hence control) is independent of the tools.\nThe measured wrench at the base sensor can be expressed as sum of the following components:\nFs = Fm + Fg + Fb (18)\nwhere F, is the motion-induced dynamic wrench, Fg is the gravity wrench, and Fb is the base wrench\nwhere Fb x Fs - Fg.\n3.2 Explicit Force Control Scheme To achieve a smooth transition from low tension to required tension, damping is needed. However, direct differentiation of force is not practical due to the noisy measurement and time delay. We therefore add damping to the system through velocity feedback. This approach has been widely used for dealing with impact force regulation in robot force control [9]. We also include the integral force feedback to reduce the steady state error and enhance robustness with respect to the time delay. The overall force control law is of the following form:\nP\n4 Experimental Results A six-axis force/toqrue sensor (AT1 Model 15/50) is mounted between the base plate and the mounting block as shown in Figure 11. The sensor outputs are interfaced to the PC through the serial communication and then, through the Ethernet, to a DSP-based motion controller by ARCS, Inc. The suture that is used in this study is made by USP (the United States Pharmacopeia), model 2-0 suture (coated, braided silk suture). We first experiment with the free tail of the suture k e d on a stand and the needle tail is attached to"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure3-1.png",
+ "caption": "Fig. 3 Specimens geometry (dimensions in mm)",
+ "texts": [
+ " As mentioned above, the friction measurement procedure requires the specimens to be machined directly from the axle and the wheel, thus reproducing exactly the actual surface conditions during the press-\u00aet, in terms of materials, contact geometry, roughness and anisotropy. In particular, the specimens are taken from the zone near the coupling surfaces, as schematized in Fig. 2: a small specimen (called a punch in the following) and a long specimen (called a body in the following) have to be machined from the two components. In the present experiments the punch was obtained from the axle, the body from the wheel. The geometry of the specimens is reported in Fig. 3. The examined materials are carbon steels for both elements, precisely a normalized steel with 0.3 per cent carbon and HV \u02c6 205 for the axle (A1N-UIC 811\u00b11 O) and a quenched and tempered steel with 0.5 per cent carbon and HV \u02c6 260 for the wheel (R7T-UIC 812\u00b13 O). The initial specimens roughness was Ra \u02c6 0.8 mm for the axle and Ra \u02c6 1.5 mm for the wheel. As stated above, the test apparatus was designed to be mounted on a standard axial testing machine. In particular, in the present experiment a servo-hydraulic INSTRON machine with a maximum load of 100 kN and a maximum grip distance of 300 mm was used"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002044_s0378-4754(02)00027-7-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002044_s0378-4754(02)00027-7-Figure5-1.png",
+ "caption": "Fig. 5. Data capture for door crossing ANN learning.",
+ "texts": [
+ " The first output corresponds to left rotation, the middle output means no rotation and the last one will order the robot to rotate to the right. Thereby, again only the sign of the rotation action is learned, and the magnitude of the rotation is considered fixed. To collect data in order to learn the actions to cross the door, we have used the following methodology: we mark different trajectories on the floor, in which the same actions should be performed and collect sensor data while pushing the robot along that path. Fig. 5 shows the labels assigned to the different viewpoints of the robot with respect to the door. From angle \u03b8 the action to be carried out is \u201cturn right\u201d, from position with angle \u03b1 the robot must not rotate at all, and if the sonar readings indicate that the angle with respect to the door is similar to \u2126 , then the robot will \u201cturn left\u201d. To train the network we have used a set of 22,240 input patterns. Two-thirds of them have been used to train the net and the rest to measure the accuracy, obtaining an efficiency of 97"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003364_0020-7403(88)90076-8-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003364_0020-7403(88)90076-8-Figure6-1.png",
+ "caption": "FIG. 6. Adhesive (free) roll ing, no rma l and shear tract ions. (a) v = 0.3; (b) v = 0.5.",
+ "texts": [
+ " The amount of coupling reduces as the tyre thickness is reduced and consequently the relative magnitude of the shear tractions reduces. For v = 0.5 no coupling is present in the half-plane solution, but it is introduced as the tyre thickness is reduced. The shear tractions induced are of opposite sign to those present for v = 0.3--i.e. the coupling effects due to elastic dissimilarity and finite tyre thickness are opposite in sign. Some sample traction distributions for this configuration are shown here in Fig. 6. Tract ive rolling As mentioned above, it is not possible to obtain a valid solution for the case of tractive rolling unless some slip is permitted. This can be introduced into the formulation as follows. First a guess is made for stick zone boundaries b 1, b 2 together with the direction of slip in each slip zone. The tangential matching equations (17) for those points lying in the slip zones (m/S < b I , m /S > b2) are replaced by #P . + Q. = 0, (18) where the sign is chosen to correspond with the desired direction of slip"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003695_s00604-003-0077-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003695_s00604-003-0077-2-Figure1-1.png",
+ "caption": "Fig. 1. Diagram of optical sensing system",
+ "texts": [
+ " A few drops of the resulting solution were immediately transferred and spread over the clear side of a glass cuvette. The sensing membrane was allowed to formulate and stick in position. The resulting sensing membrane was washed with distilled water and stored in either distilled water or basic buffer. Optical Measurements The cuvette with the sensing element stuck on its side wall was secured in the cell holder of a Perkin Elmer conventional spectrophometer such that the sensing element membrane was positioned in the light beam path Fig. 1. The solution in the cuvette was changed by using a disposable pipette. The change in turbidity of the sensing element as a function of analyte concentration was measured as absorbance. The spectrum was obtained at different periods of time until it reached a steady state. Sensing element evaluation was done by measuring the difference in absorbance when the sensing element was cycled between pH 3.0 and pH 9.0 many times and observing the reproducibility of the optical reading (absorption spectrum)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000572_jsvi.1995.0517-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000572_jsvi.1995.0517-Figure1-1.png",
+ "caption": "Figure 1. A rotor on rolling element bearings.",
+ "texts": [
+ " A curve fitting algorithm is developed to process the response of the Fokker\u2013Planck equation to extract the bearing stiffness parameters. The algorithm is tested by Monte Carlo simulation. 229 0022\u2013460X/95/420229+11 $12.00/0 7 1995 Academic Press Limited . . . 230 The procedure is illustrated for a laboratory rotor rig and the results are comparedwith those from the analytical formulations of Harris [4] and Ragulskis et al. [9]. The governing equation for a balanced rigid rotor supported at ends in bearings (see Figure 1) with non-linear stiffnesses can be written as x\u0308+2zvnx\u0307+v2 n [x+lG(x)]=f(t), (1) where G can be a polynomial in x and l is the unknown non-linear stiffness contribution parameter. f(t) in equation (1) represents the random excitation to the system (a list of nomenclature is given in the Appendix). The bearing surface imperfections, caused by random deviations from their standard theoretical design and progressive surface and subsurface deterioration, are large enough to cause measurable levels of vibration and can be the primary source of these excitations"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002485_1.1902843-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002485_1.1902843-Figure3-1.png",
+ "caption": "Fig. 3 Flexible-link robot with a new link deflection model",
+ "texts": [
+ " s3d, sx2+w2du\u03072, is the square of the rotational velocity at the end point of the link deflection vector wsx , td, where w2u\u03072 is due to free link elongation. From the math- ematical point of view, w2u\u03072 results in an additional kinetic energy in Eq. s4d, causing the sign problems. In this section, a no-elongation link deflection model is first proposed as a link deflection model, compatible with the bending mechanism of flexible links. Then a new dynamic model is derived based on the new link deflection model. 3.1 A New Link Deflection Model. A new no-elongation link deflection model is shown in Fig. 3. In the figure, x, u, wsx , td, and t are the position along the link of length l, joint angle, link deflection, and joint torque, respectively. X0Y0 and X1Y1 are the Transactions of the ASME Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F inertial and rotating frames, respectively. In addition, g is the deflection angle at position x along the link and is defined with cos g=\u00cex2\u2212w2 /x and sin g=w /x. 3.2 New Dynamic Modeling. As before, the position vector psu ,x ,wd indicating the end point of the deflection vector wsx , td is computed in the inertial coordinates: psu,x,wd = \u00cex2 \u2212 w2fcossu + gdi\u0304 + sinsu + gd j\u0304g = \u00cex2 \u2212 w2S\u00cex2 \u2212 w2 x cos u \u2212 w x sin uD i\u0304 + \u00cex2 \u2212 w2S\u00cex2 \u2212 w2 x sin u + w x cos uD j\u0304 , s16d where i\u0304 and j\u0304 are the base vectors of the inertial coordinates X0 and Y0, respectively"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.8-1.png",
+ "caption": "Figure 4.8. A typical universal joint mechanism.",
+ "texts": [
+ "27a) But this is not yet referred to frame 1; it remains to refer y to frame 1. The geometry provides y =sin {J0 i +cos {J0 k with Po= {J(t0 ). (4.27b) 246 Chapter 4 Then use of (4.27b) in (4.27a) delivers ro 30 = 0.1 sin /3 0 i + 0.2j + (0.5 + 0.1 cos /30 ) k radjsec, ( 4.27c) in which /3 0 is the angular placement of the arm at the time t0 shown in Fig. 4. 7. The result ( 4.27c) is the total angular velocity of the claw frame 3 relative to the machine frame 0 and referred to the yoke frame 1, at the instant of interest. The universal joint illustrated in Fig. 4.8 is a mechanism used to connect rotating shafts that intersect in a constant angle ifJ. Each connecting shaft ter minates in a U-shaped yoke. The yokes are connected by a rigid cross link, the ends of which are set in bearings in the yokes at A, B, C, and D. When the drive yoke turns as shown in Fig. 4.8, the cross link must rotate relative to the yoke about its axle AB. The motion of the cross link about the axle CD and relative to the follower yoke is similar. We are going to show by use of the general chain rule ( 4.22) that even if the angular speed w 1 of the drive shaft is constant, the angular speed m2 of the follower shaft will not be uniform. We seek the ratio m2/m 1 of the angular speeds and its maximum and minimum values. The variation in the angular speed ratio with the angle of rotation of the drive yoke for various shaft angles will be described graphically at the end",
+ " Thus, even if the angular speed w1 of the drive shaft is constant, the angular speed w 2 of follower shaft will not be uniform, except for ifJ = 0. The denominator in ( 4.28f) achieves its smallest value cos 2 ifJ at IJ = (0, n) and its greatest value 1 at IJ = (n/2, 3n/2); therefore, the angular velocity ratio has the maximum and minimum values max(w 2/w 1 ) = 1/cos ifJ min(w2/wd =cos ifJ at 0=0, n; at e = n/2, 3n/2. (4.28g) Thus, w 2/w 1 attains its greatest value when the cross link is in the position shown in Fig. 4.8, and its least value occurs after a further 90\u00b0 rotation of the drive shaft. A polar graph of the ratio (4.28f) is shown in Fig. 4.11 for a quarter revolution of the drive yoke and for various shaft angles. Notice the con siderable variation in the angular speed ratio as the shaft angle ifJ is increased. Usually, however, the universal joint is used in circumstances where the shaft angle is small so that w 2 is very nearly equal to w 1 \u2022 This is evident in Fig. 4.11 for the shaft angle \u00a2J = 10\u00b0, for example"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001508_978-1-4615-2135-8_1-Figure1.5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001508_978-1-4615-2135-8_1-Figure1.5-1.png",
+ "caption": "Figure 1.5 Screw geometry affects conveying volume and pressure development.",
+ "texts": [
+ " the match of pumping efficiency with the rheology of the material being extruded 3. strength and wear characteristics 4. surface area for heat transfer and narrow residence time distribution 5. pressure and flow distribution at the entrance to the die 6. the degree of shear or intensive mixing required 7. the degree of barrel fill 8. the motor size. The conveying volume of a screw is a function of the screw speed, dia meter and distance between flights of the screw (referred to as pitch) (see Figure 1.5): or Qv = f [cP (Hp) N] Qv = m NV where Qv = conveying volume, d = diameter of screw, Hp = pitch, N = screw speed and, m = starts on the screw shaft. The pressure (P) which these screws generate over a length (x) can be described as dp _ K [ DNIl ] dx - L2tan9 where K = constant dependent on the degree of screw intermeshing, D = screw diameter, N = screw speed, 11 = material viscosity, L = flight height and 9 = flight helix angle. From this expression it can be seen that the length of the pumping section decreases with increasing screw speed, melt viscosity and decreas ing screw helix angle"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001708_0094-114x(94)90074-4-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001708_0094-114x(94)90074-4-FigureI-1.png",
+ "caption": "Fig. I. Three views of feasible solution space,",
+ "texts": [],
+ "surrounding_texts": [
+ "Optimal eagineerin| design of gear ~ 1075\nThe MIWT procedure is briefly illustrated as follows:\n!. Specify the sample size P (according to [17], P should be at least as large as the number of objective functions), number of iterations t (t should be approximately the same as the number of objective functions [17]), and reduction factor r, [(l/P)~'k ~< \u2022 ~< w'- ' ] . 2. Calculate Z* (ideal criterion vector). Z* is calculated by solving the optimization problem k times (k is the number of objective functions). An optimal solution is generated each time as if there was only one objective function. Z* is the combination of the k optimal solutions. In gear design, for example, there are four objective functions. The problem is solved four times; each time dealing with only one objective function, and obtain four optimal solutions. These four solutions form the first Z*. 3. Rescale the objective functions and set the iteration counter c = 0. Let the interval width of weighting factors (::[i) as follows:\n= <0, I>, (18)\nfor i = i , 2 . . . . . k. There are four weighting factors, each associated wi th a design objective. These weighting factors represent the relative importance o f those objectives to the designer. The interval width defines the upper and lower l imits of the weighting factors. In this study, each weighting factor is a number between 0 and I.\n4. Set c = c + I and form a set o f weighting vectors as follows:\nIt can be seen that each vector consists of four weighting factors, and the sum of these factors in each vector is !. In other words, each vector represents a unique set of relative importance of the design objectives to the designer. 5. Randomly generate 50 x P weighting vectors from ~\u00a2cj in Step 4 (suggested in Ref. [ 17]). Note that each vector is tested against all design constraints when it is generated. Those vectors which do not satisfy all constraint functions will not be adopted. Filter those vectors and select the 2 x P most different ones.t Use these 2 x P dominating vectors to solve the 2 x P associated augmented weighted Tchebychcff equation [17]. This will generate 2 x P design solutions (criterion vectors). 6. Filter the criterion vectors from Step 5 and select the P most dominating ones. Present those to the gear designer to select the most preferred one. Let it be Z(\"L If the designer is satisfied with this solution, go to Step ! l. Otherwise, go to Step 7. The designer's involvement in this stage of design is a key. He is given the freedom to explore the impact of different relative \"importance\" of design criteria by selecting different preferred intermediate solutions. By doing so, the designer is able to explore different ideas leading to an optimal solution. 7. This step adjusts the search direction so that it is directed more toward the optimal solution. Let :~('~ be the ~: vector whose components are:\nZ* - ZI'~)-I[Y-, *. i ( Z * - Z~J) - I ] if Z * # Z~ ~ for all i, --,]'t~ -- if Z * = ,:,,\"\u00a2'~ , (20)\nif Z * # 7 (~ but :lj s.t. Z * = 7\"J\n8. This step makes sure that all weighting factors are within bounds (between 0 and I). Use the weighting vector from Step 7 and form:\nwhere\nf<0, \u2022~'J~j - r , I ) [<1~ \"j -- 0.Sr (~', ,;.~' + 0.Sr ('') if i ( { ) - 0.SP '~ ~ 0, if ).c,., + 0.Sr~, ,) >/ I, otherwise.\n(22)\n4\"These 2 x P vectors dominate all others.",
+ "1076 HUNGIaN WANG and H . ~ - I ~ WANG\n9. If e < t, go to Step 4. Otherwise, go to the next step. 10. If the gear designer is not satisfied with the result, go to Step 4. Otherwise, go to Step I 1. I I. Z ~\u00b0 is the overall optimal solution which satisfies all constraints.\nExperience indicates that generating 50 x P sample vectors can be a most critical step in the entire solution procedure. If the samples are not generated appropriately, it may take much longer to obtain the optimal solution. In other words, the efficiency of the solution procedure depends on how well the initial samples are selected.\n2.6. Example The same example used in Refs [I, 2, 5, 8] was tested using the methodology presented in this paper. The results are shown below:",
+ "Optimal enigineerinl desifln o f gear sets 1077\nInput parameters Elastic modulus: 30 x 10 + Poisson's ratio: 0.25 Addendum constant: 1.0 Dedendum constant: 1.25\nDesign remits Center distance: 3.96 (in.) Number of pinion teeth: 16 Diametral pitch: 12.13 (l/in.) Face width: !.25 (in.)\nObjective function values Weight of gear set: 12.59 (lb) Deflection: 7.96 E - 03 (in.) Estimated life: 3.96 E + 06 (rotation)\nA sample session of the optimization program is given on the following pages.\nFigures l(a-c) provide three views of the feasible solution space for the sample problem. Figure 2 is a 3-D view of the same space. Every point in the space is a feasible solution (i.e. it satisfies all constraint requirements).\nReferring to the interactive sample session, in each iteration, the designer is provided with four feasible solutions, among which he selects one. The solutions picked out by the designer from those three iterations are marked in Fig. 2 as points A, B and C. This visual presentation tool was found very helpful in the design process."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003355_tmag.1982.1061919-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003355_tmag.1982.1061919-Figure12-1.png",
+ "caption": "Fig. 12. Concertina structures at zero external field which satisfy the boundary conditions. (e) One period of the concertina.",
+ "texts": [
+ " The number of periods of the bellows is an VAN DEN BERG AND VATVANI: WALL CLUSTERS 885 N' N N Fig. 11 The linking of the tip domain structures by two triplets having cluster knots at the same edge. Dimensions: 30 X 50 pm. (a), (c), (d) Two triplets with intersecting outermost walls transforming into a triplet. (b), (e) The bifurcation of the quintet into two triplets. integer in case the magnetization in both triangular tip domains are opposite, while one half-period has to be added in case of parallel magnetization (see Fig. 12). The number of periods can be decreased by applying an external field normal to the bar such as previously pointed out by Huyer. D. Conversions of CStructure to LL and D Structures The walls and edges of the rectangle form closed loops in the case of the complete concertina structure, and no wall that fades out in a domain by gradually decreasing its rotation is left. The closed character of the Landau-Lifshitz structure is removed by the separation of the 180' Bloch wall into two parts, as previously discussed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001042_robot.1994.350911-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001042_robot.1994.350911-Figure1-1.png",
+ "caption": "Figure 1 - Three Identical Grasps of Dissimilar-6Gects",
+ "texts": [
+ " This is because most researchers used rigid body models for analyzing grasps, and the compliance between contacting objects (albeit small, in most cases) was not incorporated. As it turns out, all form closed grasps are stable, but not pll stable grasps need be form closed. It has been shown that all form closed equilibrium grasps are stable [lo]. Stability of non-form closed equilibrium grasps, however, depends not only on the arrangement of contacts, but also on the local curvatures of the grasped body and the fingers, and the magnitude of the contact force. Figure 1 gives an example of three grasps with the same arrangement of (fixed) frictionless fingers exerting identical forces (W and c are identical). Note that we use \u201cfingers\u201d in this paper as a generic term to represent any link, finger, effector, or fixture in point contact with the object being grasped or restrained. In Figure la, it can be seen from inspection that the grasp is stable. In Figure 1 b, however, the grasp is unstable. The stability of the grasp in Figure IC cannot be determined by inspection. Stability of a grasp can also result from external forces. An example of a non-form closed stable grasp is a brick lying on a flat, frictional surface. In this paper we refer to all external forces as \u201cgravity\u201d. Previous work in the area of grasp stability has been done by Hanafusa and Asada [3], who noted the dependence of the stability of certain grasps on local geometry. Cutkosky and Wright [2] studied two finger grasps and noted that the stability depended upon the forces applied and the local curvature"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure1-1.png",
+ "caption": "Figure 1. Symmetric skeletal structures and their symmetry operators: (a) a grid; (b) planar frames; and (c) a 3-D frame.",
+ "texts": [
+ " It is pointed out that this operation is significant when each of the rotation and reflection are not individually among the symmetry operations of the object. (4) Inversion through the centre of symmetry which is a special case of Sn with n = 2, and is denoted by (i). (5) Identical symmetry (e), which maps an arbitrary object into itself, and is one of the symmetry operations of any given object; either symmetric or asymmetric. A number of symmetric skeletal structures and their symmetry operators are depicted in Figure 1. The interpretation of principal axis is simply shown in the grid of Figure 1(a), where there are two Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm C2 axes and one C4 axis. Based on the above definitions, the latter will be the principal axis of the structure. The symmetry centre of this grid is joint \u2018i\u2019. The concept of different kinds of symmetry planes can be recognized from the planar frames of Figure 1(b), and the three-dimensional frame of Figure 1(c). Symmetry operations of an object under the combination of transformation operations comprise a group, which is called a symmetry group. Symmetry groups are classified based on symmetry operations which make a group up. Figure 2 shows some symmetric structures and their symmetry groups. The symmetry group of a finite body is sometimes referred to as the point group. There are several methods for categorizing the point groups. In Figure 2, the point groups are named based on Scheonflies method, which is more conventional than the other approaches"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002414_s0043-1648(03)00173-x-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002414_s0043-1648(03)00173-x-Figure1-1.png",
+ "caption": "Fig. 1. Friction test. (a) Equipment; (b) sphere/plane contact between chert and picrolite or diabase.",
+ "texts": [
+ " The specific abrasion energy (in J/mm3) is defined as the ratio of the energy spent during the scratch process to the wear characterized by the volume of removed material on a settled scratching distance. The simulation of wear by friction is performed to characterize the mechanisms of deformation of materials under specific tribological constraints. The equipment developed is able to apply on the studied surface a normal force of 10 N (constant load) and to measure a maximum tangential force of 5 N, (Fig. 1a). In the case study presented here, a contact sphere/plane was chosen to get read of problems of parallelism that occur while plane/plane contacts. A sphere of picrolite or diabase, showing a radius of curvature of 5 mm (natural convexity of river pebbles, (Fig. 1b), was applied on a knapped surface of Lefkara chert (type B, [3]). The number of cycles were of 256 and a constant normal force of 5 N was applied. Every sequence of friction\u2014 five for the picrolite and five for the diabase\u2014were realized without any additive. The evolution of the surface of the chert is evaluated with the help of two topographic measurements, realized exactly at the same zone, before and after friction. A surface of 2.4 mm \u00d7 1.8 mm was measured with a white light interference microscope, the lateral resolution is 1 m, and the vertical resolution of 2 nm"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.15-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.15-1.png",
+ "caption": "Figure 2.15. The locus generated by the motion of a point P on the circumference of a circle that rolls without slipping along a straight line is a cycloid.",
+ "texts": [
+ " It should be observed that the acceleration is directed from C toward 0. (e) The equation of the path traced by P in the frame f/J = { G; ik} is determined by integration of (2.27) in which v p = dX(P, t)/dt, v0 =awi, and roxx= -aw(cos.8i+sin8j) are used to express the right-hand side of (2.27) in terms of e and w; namely, dX(P, t)/dt = aw(l- cos O)i- aw sine j. (2.73) Assigning X= 0 at e = 0 and writing w = d8jdt, we determine the motion X(P, t) =Xi- Yj =a(O- sin O)i +a( cos 8-l)j (2.74) whose locus, shown in Fig. 2.15, is a cycloid with parametric equations X= a(O- sin 8), Y=a(l-cos8). (2.75) The reader may find it helpful to demonstrate that the motion (2.74) or (2.75) also may be obtained by geometrical construction based on Fig. 2.15. 0 Two moving rigid bodies that come into contact obviously cannot penetrate one another. In fact, they can maintain their contact with each other only so long as they have the same component of velocity in the direction normal to their surfaces at their instantaneous points of contact; otherwise, the bodies would separate. If their mutual normal velocity component is not 112 Chapter 2 zero, then one body pushes to drive the other in their common normal direc tion. This driving contact, however, may involve slipping in the tangential plane between the two surfaces, so that the tangential velocity components of their instantaneous contact points will not be equal"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001200_jjap.38.5660-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001200_jjap.38.5660-Figure3-1.png",
+ "caption": "Fig. 3. Relationship of unit vectors in the monostable PS-SSFLC, where c and s represent the c-director of the FLC molecules and mesogenic side chains, which is in the direction of \u03c6 = 0, respectively.",
+ "texts": [
+ " We also assume that in Y = 0 to Y = d/2, \u03c6(Y ) =\u03c6s + ( d\u03c6 dY ) Y =\u03c6s + ( \u03c6c \u2212 \u03c6s d/2 ) Y, (6) where \u03c6s and \u03c6c are the azimuthal angle of the c-director of the FLC molecules on the substrate surface and chevron interface, respectively, and are expressed as sin\u03c6s = tan \u03b4 tan \u03b8 + sin \u03b2 sin \u03b8 cos \u03b4, (7) sin\u03c6c = tan \u03b4 tan \u03b8, (8) where \u03b8 is the cone or tilt angle. Then, the in-plane tilt angle of the FLC molecules on the substrate surface (\u03c80 = \u03c8d = \u03c8) is given by tan\u03c8 = sin \u03b8 cos\u03c6s sin \u03b4 sin \u03b8 sin\u03c6s + cos \u03b4 cos \u03b8. (9) In the monostable PS-SSFLC, mesogenic side chains may be directed toward the FLC molecules with \u03c6 = 0 or \u03c0 during the photocure according to the applied voltage. Now if we assume that this direction corresponds to \u03c6 = 0 after the photocure as shown in Fig. 3, then the free energy per unit area in terms of the interaction between the FLC molecules and the side chains at a plane of Y = Y \u2032 ( f Y \u2032 ps ) may be expressed as f Y \u2032 ps =\u2212 \u03b3ps(cY \u2032 \u00b7 s) =\u2212 \u03b3ps cos\u03c6(Y \u2032), (10) where c and s represent the c-director of the FLC molecule and side chain, respectively. If it is defined that f Y \u2032 PS = f Y \u2032 ps 1(Y \u2212 Y \u2032), (11) the free energy in terms of the polymer stabilization FPS is given by FPS = 2 \u222b d/2 0 f Y PSdY, (12) where the effective area A is 1 m2. Thus, the total free energy of the monostable PS-SSFLC (FPS-SS) in the quiesent condition can be expressed as FPS-SS = FSS + FPS"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001353_s0921-8890(96)00041-3-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001353_s0921-8890(96)00041-3-Figure2-1.png",
+ "caption": "Fig. 2. Active suspension system.",
+ "texts": [
+ " Another area of Mechatronics design where major enhancements in performance can be achieved is that of suspension systems for transport vehicles, mobile robots, off-shore boat decks and other applications where it is necessary to \"iron-out\" higher frequency disturbances while sustaining a lower frequency loading. A conventional passive suspension is unable to meet these conflicting demands. However an active, or semi- active system may be designed to do so. If, in addition, consideration is given to the underlying physics of the problem, useful gains in performance can be made [3]. Figure 2 shows a semi-active system that might form the basis of a suspension system for a vehicle in which it is desired that the weight of passengers should not cause net downward deflection of the vehicle body. The air-spring system is the primary low-pass filter for road bumps which would not, in itself, compensate for passenger loading. In parallel is a high-pass active element consisting of a damped spool-valve actuated by the movement of the wheels relative to the body. Fig. 3(a) shows the response of the passive airspring suspension, and Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.15-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.15-1.png",
+ "caption": "Figure 1.15. Pin motion in a bell crank mechanism.",
+ "texts": [
+ " The result may be established by use of ( 1.82 ). For the case k = 1, we obtain ( 1.85) This formula shows that R is least at x = 0. Hence, Rmin = 1/2 em and Kmax = 2 em -I. The solution, by ( 1.84 ), is a max = SOn = 50i cmjsec2 at the origin (0, 0). The radius of curvature at ( 1, 1) is found from ( 1.85 ); we get R = 5312 ...;-2 em. 0 Example 1.13. A small guide pin Pis attached to a telescopic arm OP of a bell crank mechanism which is hinged at 0. The pin must move in a parabolic track as shown in Fig. 1.15a. At point A it has a speed of 10 ftjsec Kinematics of a Particle 37 and a rate of change of speed of 20 ft/sec 2 along the track. What is the acceleration of the pin at point A in the Cartesian frame t:P = { F; ik} in Fig. 1.15b? Solution. The standard equation of the parabolic track shown in Fig. 1.15 is x = cy2\u2022 Since the curve contains the point ( 4, 4 ), the constant c = 1/4 and the actual path equation is ( 1.86) The problem data being expressed in terms of intrinsic quantities suggest use of the intrinsic representation for the acceleration. With s =10ft/sec and s = 20 ft/sec 2, the acceleration given by ( 1. 71) is a= 20t + 1 00Kn at A. The cur vature of the path (1.86) at A may be determined by (1.81b). Using (1.86), we evaluate dx y dy 2' (1.87) At the point A=(4,4) we have dxjdy=2,d2xjdy2 =1/2; and by (1.81b) we find K = Js/50. Therefore, the acceleration at A is given by a = 20t + 2 Js n ft/sec 2. ( 1.88) But ( 1.88) is referred to the intrinsic basis whereas the solution is required in the Cartesian basis. Therefore, a change of basis from tk into ik is needed. It is clear from the geometry shown in Fig. 1.15b that t = cos a i + sin a j, n = sin ':1. i - cos a j, ( 1.89) wherein a is determined by tan ':1. = dyjdx = 2/y. Evaluating this at A= ( 4, 4 ), we get tan a= 1/2; and from this result we determine sino:= t;Js, coso:= 2/Js. Now (1.89) may be written as t= f (2i +j), D= f (i-2j), Substitution of (1.90) into the acceleration (1.88) yields a=2[1 +4.J5J i+4[.j5-t]jft/sec2 \u2022 ( 1.90) (1.91) This is the acceleration of the guide pin at point A in the Cartesian frame t:P. (See Problem 1.53.) D Example 1",
+ " Find at the instant t0 the intrinsic velocity and acceleration of P in ~. and determine the radius of curvature of the path at the place occupied by P at the instant t0 . 1.56. A P.article P moves with a constant speed of 27m/sec along a parabolic tra jectory y = Js x 2. What is the acceleration of P as it passes the point at x =2m? 1.57. Find the intrinsic velocity and acceleration of the pin P in the device described in Problem 1.16 when the pin is at x = 3 in. What is the curvature at this place? 1.58. The guide pin P of the bell crank device described in Fig. 1.15 has a speed of 10 ftjsec and a rate of change of speed of 20 ft/sec 2 at the point A. What is the angular speed w of the arm OP when Preaches point A? 1.59. The slotted link A of the device in the figure for Problem 1.39 controls the motion of the pin P to move with a constant speed of 25 em/sec in the parabolic groove 3x = y 2 - 9. Find as functions of y the intrinsic velocity and acceleration of P. Determine the velocity and acceleration of the link A in the Cartesian frame rp = { 0; ik} at the instant when y = 2 em"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002923_acc.2005.1470620-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002923_acc.2005.1470620-Figure4-1.png",
+ "caption": "Fig. 4. Feasible velocity sectors for the ECAV and the phantom for bounded rates.",
+ "texts": [
+ " The algorithms are essentially finite dimensional searches which can further be reduced to one dimensional parameter searches. Considered are two cases. For this case we constrain the system dynamics through bounds on the range rate and angular rate of the ECAVs and the Phantom point. We let the phantom state be ),(R , ECAV state be ),(r and the bounds on the rates be such that min max min max min max r r r R R R These constraints lead to feasible velocity sectors being rectangular regions for both the ECAV and the phantom point as shown in Fig.4. The bounds on the rates of the ECAV\u2019s state will be functions of the ECAV\u2019s aerodynamics as well as of its state. The two bounds on the phantom\u2019s range rate will be functions of the ECAV\u2019s aero-dynamics, ECAV\u2019s state and of the dynamics of the range delay. In the absence of adequate knowledge on these bounds, constant bounds are assumed on each of the rates. For the ECAV and the phantom to be contained within their respective velocity rectangles it is clear that each rate has to have bounds of opposite sign"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003244_icsmc.2004.1398398-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003244_icsmc.2004.1398398-Figure3-1.png",
+ "caption": "Figure 3: Schematic representation of the hunk move. The trunk moves horizontally at a constant speed V.",
+ "texts": [
+ " Recorded position of each marker was traced by a motion analysis software (Move-tr/2D, LIBRARY), and the positions, the angles and the angular velocity of each joint were determined. The speed data were smoothed by a six-order low-pass Butterworth Iter with a cutoff frequency of 5 Hz. 2.2 Numerical experiments In this section, the method used in this study to obtain the leg swing trajectory minimizing energy consumption is introduced. 2.2.1 A dynamical model of a leg It was assumed that a leg is a simple two-link system with two joints at a hip and a knee (Fig.2), and the trunk moves horizontally at a constant speed. Vertical movement of the trunk was ignored (Fig.3). The dynamical equation of a leg in swing phase is given as follows TI = (II + I2 + 2A&L1S2 cosSz + Af2L:)& -A4zL1S2(201 + & ) & ~ i n 8 ~ +g(A;r,Sl + A.lr,L,) sin81 +(I2 + A4zLiS2 C O S ~ ' Z ) & +gA42Sz sin(& + 8 2 ) (1) + A ~ ~ L ~ s ~ ~ ~ ~ sin 02 +gAGSz sin(& + 02) (2) T* = ( I 2 +A;12L1S~cosOz)& +12B2 where TI and r2 are a hip and a knee joint torque, respectively, and 81 and B2 are angles of a hip and a knee joint, respectively(Fig.2). I,, Mi, Li and Si represent the inertia moment around center of mass, the mass, the leg length and the center of mass of each link, respectively, and the subscript i=l indicates the thigh and i=2 indicates the leg",
+ " Such a torque pro le results in the almost constant speed of the foot io the rst half duration and the acceleration by a ballistic movement, which brings the peak value of the foot speed in the second half duration (Fig.6(d)). Large positive torque was generated on a knee joint before the end of swing phase regardless of walking speed, which would be reauired to null hack the foot and make the aound (c) I \" \" \" \" ' / 4 \" 20 \" 40 \" 60 \" 80 \" 100 percent swing [%] - contact. These characteristics of torque pro les are coincident with the estimated joint torques in previous studies (see Fig.3 in [27], Fig.5 in [26], Fig.7 in [21]). The above characteristics of leg trajectories and joint torques were also obtained when the constant Y takes Vanous values. Figure Leg trajectories during swing phase by the subject TK relative to the hip position at speeds of 3k\" (solid), 5 k \" (dotted) and 7 k \" (dot-dash). The foot trajectory (a), time Course of the horizontal position (b), vertical position (c), and speed (d) of the foot versus percent of swing. The amount of energy consumption during swing phase is shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002115_s0924-0136(02)00034-1-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002115_s0924-0136(02)00034-1-Figure10-1.png",
+ "caption": "Fig. 10. Contours of the temperature field of the roller after quenched in oil for 1 h.",
+ "texts": [],
+ "surrounding_texts": [
+ "The transient temperature field (as shown in Fig. 5) the distribution of the microstructures (as shown in Fig. 6), and the interior stress field (as shown in Fig. 7) when the heating was finished were taken as initial processes of the roller being quenched and then transferred to the tempering furnace. The furnace temperature of 300 8C could be combined to be analyzed because it is in fact a continuous cooling and then isothermal retention process for the center of the bearing roller. Water, oil and UCON were chosen as quenchants. The quenching time was 1 h."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002766_j.ijmecsci.2003.09.004-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002766_j.ijmecsci.2003.09.004-Figure4-1.png",
+ "caption": "Fig. 4. System of local coordinate axes.",
+ "texts": [
+ " For the system under consideration, the total kinetic energy is a sum of energies determined for individual masses and it is T (q; q\u0307) = 1 2 5\u2211 i=1 (vT SimivSi + !T i Ji!i): (11) Knowing the values of masses and the moments of inertia with respect to local coordinate axes of all the elements of an excavator, linear velocities of the centres of masses vsi transposed to the constant system and the angular velocities !i determined in local systems of coordinate axes, the total kinetic energy of the system considered was determined. The local systems of coordinate axes taken for calculations are shown in Fig. 4. The kinetic energy of a chassis of a mass m1 is T1 = 1 2 [vT S1 m1vS1 + !T 1J1!1]; (12) where: vS1 = [x\u0307 y\u0307 z\u0307]T; !1 = A[\u2019\u03071 \u2019\u03072 \u2019\u03073]T (13) the transformation matrix has the form A = cos\u20192 cos\u20193 sin\u20193 0 \u2212cos\u20192 sin\u20193 cos\u20193 0 sin\u20192 0 1 : (14) For small oscillation angles \u20191; \u20192; \u20193, the chassis energy is T1 = 1 2 m1(x\u03072 + y\u0307 2 + z\u03072) + 1 2 Jx1(\u2019\u03071 + \u2019\u03072\u20193)2 + 1 2 Jy1(\u2019\u03072 \u2212 \u2019\u03071\u20193)2 + 1 2 Jz1(\u2019\u03073 + \u2019\u03071\u20192)2: (15) The kinetic energy of a body of a mass m2 is T2 = 1 2 [vT S2 m2vS2 + !T 2J2!2]; (16) where: vS2 = vS1 + A1[",
+ " This energy is Vs(q) = cz \u00b7 a \u00b7 b[z2 + 1 12 \u2019 2 2(3a2 1 + a2) + z \u00b7 \u20191(b02 \u2212 b01) + 1 3 \u2019 2 1(b2 02 \u2212 b01b02 + b2 01)] +1 2 cx[2 \u00b7 x + \u20193(b01 + b02)]2 + 1 2 cy[2 \u00b7 y2 + 1 2 \u2019 2 3(a1 + a)2]: (45) It has been assumed that during the strain a soil foundation is subjected to energy dissipation, which is described by a Rayleigh dissipation function of the form: D(q; q\u0307) = 1 2 k\u2211 i=1 k\u2211 j=1 Rijq\u0307iq\u0307j: (46) Following the determination of rate of strain of the foundation resulting from displacements of the chassis with its caterpillars, the dissipation function of the system of the following form was determined: D(q\u0307) =Rza \u00b7 b[z\u03072 + 1 2 \u2019\u0307 2 2(3 \u00b7 a2 1 + a2) + z\u0307 \u00b7 \u2019\u03071(b02 \u2212 b01) + 1 3 \u2019\u0307 2 1(b2 02 \u2212 b01b02 + b2 01)] + 1 2 Rx[2 \u00b7 x\u0307 + \u2019\u03073(b01 + b02)]2 + 1 2 Ry[2 \u00b7 y\u0307 2 + 1 2 \u2019\u0307 2 3(a1 + a)2]: (47) Non-potential generalized forces result from cutting forces that are formed on the edge of the bucket during operation of an excavator. It has been assumed, in conformance with the literature [6,7], that components of this force, the tangent and the normal, are proportional to corresponding components of the bucket edge velocity during the digging of a soil (point K in Fig. 4) and they are as follows: Pt = P(v) vt(t) vK(t) ; Pn = P(v) vn(t) vK(t) ; (48) where P(v) is the total cutting force applied to the bucket edge, resulting from the values of forces acting in the servo-motors of an excavator gear, while the tangent force Pt and the normal Pn are total forces of cutting of a soil and resistances of friction of the bucket against the soil formed in the tangent and normal direction. Non-potential generalized forces are: Qx = [Pn cos( 2 + 3 \u2212 1) \u2212 Pt sin( 2 + 3 \u2212 1)] sin ; Qy = [Pt sin( 2 + 3 \u2212 1) \u2212 Pn cos( 2 + 3 \u2212 1)] cos ; Qy =Pt cos( 2 + 3 \u2212 1) + Pn sin( 2 + 3 \u2212 1); Q\u20191 =\u2212[Pt sin( 2 + 3 \u2212 1) \u2212 Pn cos( 2 + 3 \u2212 1)] \u00b7[h3 + lw sin 1 \u2212 lr sin( 2 \u2212 1) \u2212 ll sin( 2 + 3 \u2212 1)] cos + [Pt cos( 2 + 3 \u2212 1) + Pn sin( 2 + 3 \u2212 1)] \u00b7{[b3 + lw cos 1 + lr cos( 2 \u2212 1) + ll cos( 2 + 3 \u2212 1)] cos \u2212 b2}; Q\u20192 = [Pn cos( 2 + 3 \u2212 1) \u2212 Pt sin( 2 + 3 \u2212 1)] \u00b7[h3 + lw sin 1 \u2212 lr sin( 2 \u2212 1) \u2212 ll sin( 2 + 3 \u2212 1)] sin + [Pt cos( 2 + 3 \u2212 1) + Pn sin( 2 + 3 \u2212 1)] \u00b7[b3 + lw cos 1 + lr cos( 2 \u2212 1) + ll cos( 2 + 3 \u2212 1)] sin ; Q\u20193 =\u2212[Pt sin( 2 + 3 \u2212 1) \u2212 Pn cos( 2 + 3 \u2212 1)] \u00b7[b3 + lw cos 1 + lr cos( 2 \u2212 1) + ll cos( 2 + 3 \u2212 1)] cos \u00b7 sin \u2212[Pn cos( 2 + 3 \u2212 1) \u2212 Pn sin( 2 + 3 \u2212 1)] \u00b7{[b3 + lw cos 1 + lr cos( 2 \u2212 1) + ll cos( 2 + 3 \u2212 1)] cos \u2212 b2} sin ; (49) where ll is the distance of the cutting edge of the bucket K , from the joint C of the mounting of the bucket and the arm (Fig. 4). After the determination of the kinetic and potential energy, and the dissipation function of the system under consideration, and then performing formal procedures on these expressions with respect to the generalized velocities and time, and with respect to the generalized coordinates on the basis of Eqs. (5), we obtained a coupled system of di8erential, non-linear equations of the second order, describing the dynamics of the excavator analysed during the digging of a soil foundation. In the vector notation, the system of equations obtained has the form: A0 Pq + A1q\u0307 + A2q = f(q\u0307; q; t); (50) where A0, A1, A2 are the matrices of the masses and moments of inertia, respectively, reduced to the system of axes related to the chassis, dumping of the soil foundation and its Dexibility",
+ " Numerical data characterizing a single-bucket excavator on a caterpillar chassis of a bucket capacity of 1:10 m3 and soil foundation of mechanical properties corresponding to =ne-grained cohesive, consolidated soils of modulus of strain E = 10 MPa [4], were applied. \u2022 Basic numerical data are as follows: \u2022 The chassis mass m1 = 11 000 kg. \u2022 The body mass m2 = 6000 kg. \u2022 The jib mass m3 = 3500 kg. \u2022 The arm mass m4 = 1200 kg. \u2022 The bucket mass m5 = 900 kg. \u2022 The length of the jib (the distance AB between the joints mounting the jib with the body and the arm, Fig. 3) lw = 4:4 m. \u2022 The length of the arm (the distance between the joints BC Fig. 3) lr = 2:1 m. \u2022 The distance of the bucket edge K from the mounting joint C (Fig. 4) ll = 1:2 m. \u2022 The width of the caterpillars a = 0:5 m. \u2022 The length of the caterpillars b = 2:8 m. \u2022 The caterpillar track a1 = 2:0 m. \u2022 The equivalent rigidity of a soil foundation in the vertical direction cz = 9; 550; 000 (N=m2)=m. \u2022 The equivalent rigidity of a soil foundation in the horizontal direction cx = cy = 4; 000; 000 N=m. \u2022 The equivalent viscosity of a soil foundation Rx = Ry = Rz = 250 kNs=m. \u2022 The calculations were made for the process of getting a soil with a bucket and with an arm and a bucket"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002746_0278364905060149-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure2-1.png",
+ "caption": "Fig. 2. Two types of PKM using extensible limbs with linear scale units.",
+ "texts": [
+ " After that, we discuss secondly the latter group of factors, the frame deformations. The author\u2019s previous paper (Oiwa 2002) briefly reported fundamentals of two compensation methods for the mechanism error and the frame deformations. In this paper, some experiments demonstrate the effect of the compensation system. The method mentioned in this section can be applied to PKMs employing an actuated prismatic joint that is equipped with a linear scale unit measuring the change in the length of the limb, as shown in Figure 2. Figure 2(a) shows a general hexapod-type six-degrees-of-freedom parallel manipulator consisting of 6-SPU or 6-SPS subchains. Figure 2(b) shows a tripod-type three-degrees-of-freedom parallel manipulator consisting of 3-SPR subchains. Hereafter, S, P, U, and R represent spherical, prismatic, universal, and revolute joints, respectively. Recent studies (Oiwa 2000; Oiwa and Tamaki 2000) have reported that a joint\u2019s translational error in a limb\u2019s direction strongly affects the moving platform\u2019s motion error of PKM. In other words, the distance of the spherical joints located on both ends of the limb (that is, the length of the limb) is very important for positioning the platform accurately",
+ " In addition, because most of the measurement loop is made of a low expansion alloy, the temperature fluctuation has little effect on the length of the measurement loop. Such a structural concept, which separates the measurement system from the machine structure, has been termed a \u201cmetrology frame\u201d (Bryan and Carter 1979). The compensation devices for the joint errors and the link expansion, described in Sections 2.1 and 2.2, respectively, were adopted in an experimental CMM (Oiwa 1997, 2000) shown in Figure 8. This CMM uses the three-degrees-of-freedom parallel manipulator shown in Figure 2(b). The sectional view of an extensible limb is shown in Figure 9 in detail. Using the same method as that shown in Figure 3, an electrical comparator (Mahr 1202IC+1304K) is installed in the spherical joints connecting the limbs with the machine frame. Two electrical comparators are also used to measure the errors of the revolute joint as shown in Figure 4(b). Moreover, Super-Invar rods connect a scale unit (Sony BS75, with measuring length at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from 220 mm and resolution 50 nm) with the spherical joint and the revolute joint, respectively, to eliminate the influence of the limb\u2019s thermal and elastic deformations according to the same method as that shown in Figure 5",
+ " Therefore, in this paper, a surface plate mounting for the workpiece is used as an inert reference surface. If the base platform\u2019s position and orientation, which are represented in a coordinate system located on the surface plate, are measured while the machine is in process, the thermal and elastic deformations of the frame can be compensated independent of the structural and the material configurations of the machine base and the frame. In general, the three joints on the base platform of a tripodtype PKM shown in Figure 2(b) are located at regular intervals of 120 degrees. Moreover, two of the six joints on the base platform of a Hexapod-type PKM, shown in Figure 2(a), are closely located; thus, common PKMs have three joint supports mounting the mechanism. Thus, when three reference points are set on each joint support as shown in Figure 23, the position and orientation of the mechanism\u2019s base platform can be expressed by the coordinates of the reference points. Furthermore, the three distances among them, t1 \u2212 t3, represent the dimensions of the base platform. On the other hand, six reference points placed on the surface plate express its position and orientation",
+ " Then the axis of the rod must pass the reference point or the measurement point to minimize the influence of the joint support\u2019s motion error. The sensor can also be arranged at either end of the rod. If the distances between the surface plate and the joint supports, u1 \u2212 u6, are considerably long, some non-contact displacement sensor systems (e.g., a laser interferometer system) are utilized as shown in Figure 27. The combination of the sensor and the rod also measures the distance changes among the three joint supports, t1 \u2212 t3. In the PKM shown in Figure 2, the mechanism is suspended from the frame. This compensation system can be successfully utilized even if other configurations of the PKM are adopted. For example, a PKM can be held in the inverted position as shown in Figure 28. Figure 29 shows another configuration of a PKM that is manipulating the workpiece. The compensation device for the frame deformation, described in Section 4, was installed in an experimental CMM (Oiwa 1997, 2000) as shown in Figure 8. This CMM uses a parallel manipulator with three degrees of freedom, which is shown in Figure 2(b). A triangular-prism-shaped aluminum truss frame supports the manipulator through three spherical joints. A surface plate made of low-expansion cast iron at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from and the aluminum frame are mounted on a vibration-isolation table made of stainless steel. Each extensible limb of the manipulator is expanded and contracted by an AC servomoter and a ball screw. Three linear scale units (Sony, with measurement length 220 mm and accuracy \u00b10"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000708_s0956-5663(97)00032-8-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000708_s0956-5663(97)00032-8-Figure3-1.png",
+ "caption": "Fig. 3. The configuration of the chemiluminescence flow cells.",
+ "texts": [
+ " The former reagent contained 2\u00b75 units/ml ARP and 12\u00b75 mM luminol in 0\u00b72 M sodium carbonate buffer (pH 10\u00b70), the latter solution contained 12\u00b75 mM luminol and 10 mM 4-iodophenol in 0\u00b72 M sodium carbonate buffer (pH 9\u00b70). These were the optimal conditions reported for each system and the results are shown in Fig. 2. The response of the ARP-luminol system was overwhelmingly higher than that of the HRPluminol-4-iodophenol system, so the ARP-luminol chemiluminescence mixture was used in the subsequent experiments. Next, we investigated the construction of the chemiluminescence flow cell. Four types of flow cells were examined (Fig. 3) and the results (Fig. 4) show that the maximum response was observed with a type IV cell. Therefore, a transparent spiral tube was employed as a chemiluminescence flow cell in this sensor system. We investigated the effects of each reagent, i.e. FAD, TPP, pyruvate and Mg2+, in the PyrOx reaction mixture on the background chemiluminescence. The PyrOx reaction mixture used previously (Ikebukuro et al., 1996b) contained 2 mM pyruvate, 0\u00b76 mM TPP, 0\u00b71 mM FAD and 5 mM MgCl2 in 0\u00b702 M HEPES buffer (pH 7\u00b70)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003486_j.oceaneng.2004.11.003-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003486_j.oceaneng.2004.11.003-Figure1-1.png",
+ "caption": "Fig. 1. Co-ordinate systems for the description of ship motion.",
+ "texts": [
+ " Between the 18 types of manoeuvering tests only the Turning Test, mainly used to calculate the ship\u2019s steady turning radius and to check how well the steering machine performs under course\u2014changing maneuvers, Z-Manoeuvring Test, used to compare the manoeuvering properties and control characteristic of a ship with those of other ships and the Stopping Test (crash-stop and low-speed) used to determine the ship\u2019s head reach and manoeuverability during emergence situations, are recommended by all Organizations. The remainder of this paper is organised as follows. Section 2 deals with the modelling problem, Section 3 describes the identification procedure and, finally, Section 4 discusses results, highlighting some concluding remarks. In the process of analysing the motion of a ship in 2 degrees of freedom (DOF) it is convenient to define two co-ordinate systems as indicated in Fig. 1. The moving coordinate frame X0 Y0 is conveniently fixed to the ship and is denoted as the body-fixed frame. The origin of this body-fixed frame is usually chosen to coincide with the centre of gravity (CG) when CG is in the principal plane of symmetry. The earth-fixed co-ordinate frame is denoted as X Y. The angle J is the difference between heading and track course, VL is the forward velocity measured by the log, VT is the velocity in starboard direction and d the rudder angle. The co-ordinates (x,y) denotes the ship\u2019s position along the track"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001708_0094-114x(94)90074-4-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001708_0094-114x(94)90074-4-Figure2-1.png",
+ "caption": "Fig. 2. 3-D view of feasible solution space.",
+ "texts": [
+ " The results are shown below: Optimal enigineerinl desifln o f gear sets 1077 Input parameters Elastic modulus: 30 x 10 + Poisson's ratio: 0.25 Addendum constant: 1.0 Dedendum constant: 1.25 Design remits Center distance: 3.96 (in.) Number of pinion teeth: 16 Diametral pitch: 12.13 (l/in.) Face width: !.25 (in.) Objective function values Weight of gear set: 12.59 (lb) Deflection: 7.96 E - 03 (in.) Estimated life: 3.96 E + 06 (rotation) A sample session of the optimization program is given on the following pages. Figures l(a-c) provide three views of the feasible solution space for the sample problem. Figure 2 is a 3-D view of the same space. Every point in the space is a feasible solution (i.e. it satisfies all constraint requirements). Referring to the interactive sample session, in each iteration, the designer is provided with four feasible solutions, among which he selects one. The solutions picked out by the designer from those three iterations are marked in Fig. 2 as points A, B and C. This visual presentation tool was found very helpful in the design process. 1078 HL,~GUN W ~ 3 and Hsu-PtN WANG I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 2O 21 22 23 24 25 26 27 28 29 3O 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 6] 62 63 64 65 66 67 68 69 70 71 72 73 S A M P L E S E S S I O N INPUT PARAMETER VALUE FOR GEAR DESIGN For FILE INPUT, key in 0 For interactive input, key in 1 0 Please input the data file name '8earl Mat\" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *** Choose your FAVORITE from the following 4 *** *** alternatives by entering the number"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002731_j.ijmachtools.2004.03.005-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002731_j.ijmachtools.2004.03.005-Figure9-1.png",
+ "caption": "Fig. 9. A sample flange ) selected points for both A and B.",
+ "texts": [
+ " 5(b)\u2013(d) occur, a crispy force corresponding to a solid collision is output. This force indicates that the contact is invalid, and the stylus must be repositioned to select a surface point so that only the stylus tip is in contact with an object. The above mechanics model provides a kind of fidelity as if the user is operating on a real CMM. Measuring points are selected according to the tolerance type and its requirement and the shape and size of the part. Taking the measurement of the parallelism between planes A and B of a flange shown in Fig. 9(a) as an example part to demonstrate the measuring point selection process using the haptic device. Planes A and B are selected as reference and actual plane, respectively. Parallelism is a kind of orientation tolerances. Datum plane should be measured first. The haptic point selection procedure of the parallelism measurement of two planes is described as following: 7. Collision in 2D: (a) at time t and (b) at time t\u00fe Fig. 1. Step 1 L oad the CAD model and the tolerance specifications. Step 2 D etermine the sampling strategy according to the tolerance requirement, feature shape and size, and operator\u2019s skill. Fig. 9(b) shows the interface of choosing the number of sampling points. Step 3 R otate, move, or zoom the scene or the part to view the whole shape of a plane, for instance, datum plane A of the flange. Step 4 M ove the stylus of the haptic device to move and control the probe of HVCMM. Step 5 P oint the probe tip at Plane A. If a desired point can be reached, it means this point is accessible. the probe tip and an object: (a) surface normal n in-line with probe; (b) surface normal n at an and its measurement: (a) a flange; (b) choose point number; (c) selected points for A; and (d Step 6 M ark the point and record its coordinates and sequence. Step 7 R epeat Steps 5\u20136 until all desired points on this plane are selected. Fig. 9(c) gives the point selection result of the plane A. Step 8 R epeat Steps 3\u20137 to select points on another plane, for instance, actual plane B of the flange. The point selection results of planes A and B are illustrated in Fig. 9(d). When measuring some features of complex parts, such as holes at different angles, a bent probe is required. Fig. 10 shows the measurement of inclined bores of a simplified V6 engine block with a bent probe. The point selection procedure is the same. The small highlighted points inside bores are selected by moving the stylus. These points are guaranteed to be accessible in real measurement. If a measuring point is not satisfactory, it is free to re-select another point. This paper has presented a novel CMM inspection path planning environment, the HVCMM, which makes use of haptic modeling technique for CMM off-line programming"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000732_s0301-679x(98)00043-7-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000732_s0301-679x(98)00043-7-Figure9-1.png",
+ "caption": "Fig. 9 Experimental apparatus",
+ "texts": [
+ " In this case, the pumping effect of the bearing with the compliant surface becomes smaller than that of the rigid surface bearing due to the deformation of the rubber surface shown in Fig 8. At a bearing clearance of 10 or 15 mm, however, higher maximum pressure is obtained in the compliant surface bearing than in the rigid surface bearing. This is because the deformed rubber surface acts as a sort of pocket in a hydrostatic bearing and can keep the water pressure higher. 336 Tribology International Volume 31 Number 6 1998 Comparison with experimental results Fig 9 shows the experimental apparatus. The shaft is set vertically and the load imposed on the shaft is given by the air cylinder located above the shaft. Pressurized water is fed into the rotating shaft through a non-contact seal. In order to measure the bearing torque, the upper conical bearing is supported by an aerostatic journal bearing. The displacement of the shaft is measured by the non-contact displacement probe using the eddy current. The position of the lower conical bearing is also measured to confirm that its position is always constant, even when load is imposed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000994_91.580792-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000994_91.580792-Figure2-1.png",
+ "caption": "Fig. 2. Membership functions of the input and output linguistic variables (N: negative, ZE: zero, P: positive, B: big, S: small).",
+ "texts": [
+ " The form and the number of the membership functions are defined with the function rulebase( ), which is also used for the creation of the control rules. We have three input linguistic variables: , the reel position on the bar, the speed of the reel, and the angle of the bar, respectively, and one output linguistic variable , the dc voltage of the motor, which is used as the control signal for the system. Their membership functions have the form of a triangle and are placed evenly throughout the whole defined space and , respectively, as shown in Fig. 2. We propose that all input variables have an equal definition space . If we want to fit our variables into a certain definition space, we should multiply each variable with the input gain . The output fuzzy set B in each iteration is calculated with the madmani( ) function mamdani (17) where is the input gain vector determined by a human expert and states and are the estimated states. TABLE I RULES MATRIX FOR THE FUZZY STATE CONTROLLER The control signal is calculated with defzfir( ) function defzfir (18) where equals the output fuzzy set, equals the output definition space, and COG is the defuzzification method"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002333_a:1025991618087-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002333_a:1025991618087-Figure12-1.png",
+ "caption": "Figure 12. Graphical illustration of the reactions during the support phase.",
+ "texts": [
+ " During the flying phase (0.4\u00f71.5 sec) the most important for the somersault performance are variations in hip and shoulder control torques. The control torques in elbow and neck play also an essential role. Applying qd(t), q\u0307d(t), q\u0308d(t), Rxd(t) andRyd(t) in the scheme of Equations (17), the joint reactions \u03bbd(t) during the specified motion can be determined as well. The simulation results, limited to the reactions in A, K and H joints, are presented in Figure 11. They are then illustrated graphically in Figure 12 for the support phase. The question of what loads (and in which direction) cross the joints during this and other sport activities may be of considerable interest to the clinicians and trainers. Evidently a more detailed model of muscle forces and joint interactions is needed to make the analysis more valuable. To solve the direct dynamics problem in which the calculated control is used as the input signal, the dynamic equation (15) needs to be rearranged to q\u0308 = M \u22121 (q)(f(q) \u2212 d(q, q\u0307) + r(q) + B T \u03c4 d(t)), (23) where \u03c4 d(t) is a continuous time function fitting the inverse dynamics discrete solution"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.9-1.png",
+ "caption": "Figure 4.9. Exploded view of the universal joint showing the three imbedded frames.",
+ "texts": [
+ " We seek the ratio m2/m 1 of the angular speeds and its maximum and minimum values. The variation in the angular speed ratio with the angle of rotation of the drive yoke for various shaft angles will be described graphically at the end. Let ro 10 = ro 1 and ro 20 = ro 2 denote the respective angular velocities of the drive shaft and follower shaft, and write ro 30 for the unknown angular velocity of the cross link, all relative to a preferred frame cp 0 = { F; ik }. These vectors are identified in Fig. 4.9 as the angular velocities in cp 0 of three reference frames: cp 1 ={0;G 1 ,y 1,J1d fixed in the drive yoke; cp 2 ={0;G2 ,\"{ 2 ,J12 } imbedded in the follower yoke; and cp 3 = { 0; y 1 , y 2 , y 3 } attached to the rigid cross link. The kinematic chain rule ( 4.22) thus yields two relations con necting these vectors: (4.28a) wherein ro 31 is the angular velocity of the cross link (frame 3) about the axle Motion Referred to a Moving Reference Frame and Relative Motion 247 We note in Figs. 4.9 and 4",
+ "28c) This completes our application of the kinematic chain rule for angular velocity vectors. The rest of the analysis concerns the interpretation of ( 4.28c) in terms of the shaft angle and the angle of rotation of the drive yoke. Since \"{ 2 is perpendicular to both \"{ 1 and 0' 2 , we may write \"{ 2 =rxa2 X\"{ 1 , where rx is an unknown scalar. Therefore, with 'Y 1 x 'Y 2 = 'Y 1 x ( rxa 2 x 'Y d = rx[a 2 - (\"/ 1 \u2022 a 2 ) \"{ 1], and noting also that \"{ 1 \u00b7 a 1 =0, we obtain from (4.28c) (4.28d) where cos 2 1:1) - 1/ 2, w 32 = -w 1 et sin 1> sin l.i. Motion Referred to a Moving Reference Frame and Relative Motion 327 Thus, find the absolute angular velocity ro 30 of the cross link referred to the cross-link frame
. (c) What are the absolute velocities of the end points A and D on the cross link? (d) Describe an alternative scheme for the determination of the results found here. 4.26. (a) Use the results of the previous problem to determine the absolute angular acceleration of the cross link of the universal joint referred to the cross-link frame p are rotation angles of the hob cutter and gear blank, respectively; and F is the setting angle of hob cutter",
+ " Also, kinematic relation between different coordinate systems can be obtained by applying coor- 108 / Vol. 119, MARCH 1997 Transactions of the ASME Copyright \u00a9 1997 by ASME Downloaded From: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 01/30/2016 Terms of Use: http://www.asme.org/about-asme/terms-of-use dinate transformation matrix equations. The transformation ma trix [My] transforms the coordinates from coordinate system Sj(Xj, Yj, Zj) to Si{X,, Fj, Zj). Based on the relationship in Fig. 2, matrices [M,*], [M/-r], and [M,,/] can be represented as follows: [M,\u201e] = [MfA = cos (f),, -s in (ph 0 0 sin 0;, cos h 0 0 0 0 0 0 1 \u20ac,. 0 1 - 1 0 0 0 0 -sin r -cos r 0 0 \u2014cos r sin r \u20ac\u0302 0 1 4 0 (1) (2) and [M\u201ef] = cos cjip \u2014sin (j),, 0 0 sin \u00bb,, 0 0 cos y sin F + miyf)nxf + (XfSin F \u2014 miXf)nyf + XfCOS Tn^f] = 0, (22) Downloaded From: http://mechanicaldesign",
+ "org/about-asme/terms-of-use where mi = N^INp-, NH is the number of start of the hob cutter and Np is the number of worm gear teeth. The worm gear tooth surface can be obtained by considering the locus of hob cutter represented in coordinate system 5,, and the equation of meshing expressed in Eq. (22), simultaneously. Therefore, Eqs. (6) and (22) represent the worm gear tooth surface. (b) Point Or is moving in Xf - Zf plane In the manufacturing of worm gear, the center of hob cutter can be set at the fixed point M (Fig. 2) . However, when the hobbing machine is used to manufacture spur or helical gears, the motion of hob cutter is in Xf \u2014 Z; plane. Therefore, the motion of point O^ (a point on the hob cutter axis) is a curve and is moving in Xf \u2014 Z/plane. When velocities Vx and Vz have a specific relation in the manufacturing process, the locus of point O, can be expressed as follows: fixfh, Zfh) = 0. Then, the tangent direction can be obtained by tan 7 = dXn (23) (24) where y represents the angle formed by the tangent vector of hob cutter path and Z/-axis",
+ " (28) is simplified as: [-Z/COS r - '\u0302j sin r + i^ cos T + yfNJNp\\n^f -I- \\Xf sin r - 4 sin r - XfNJNp]nyf = 0 (31) The tooth surfaces of a spur gear can be obtained by considering the locus of hob cutter represented in the coordinate system Sp and the equation of meshing shown in Eq. (31), simultaneously. Therefore, Eqs. (6) and (31) represent a spur gear's tooth sur faces. (ii) Noncircular gears manufacturing The generation of noncircular gears can also be considered a two-dimensional problem. However, the distance \u20ac\u0302 shown in Fig. 2 is not a constant in the generation process of noncircular gears. In this case, \u20ac\u0302 is equal to the distance between the center of rotation of noncircular gears Zp and the axis of hob cutters Zi,. A noncircular gear's tooth surface can be obtained by con sidering the locus of hob cutter represented in the coordinate system Sp and the equation of meshing shown in Eq. (31), simultaneously. Therefore, Eqs. (6) and (31) represent the tooth surface of noncircular gears. Because the generation of noncir cular gears can be considered a two-dimensional problem, the rack cutters can be used to develop the mathematical model of noncircular gears"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003926_1.338581-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003926_1.338581-Figure5-1.png",
+ "caption": "FIG. 5. Triangle T(u+,u_) on the (a - /3) plane.",
+ "texts": [
+ " In the case when n is a triangle, the integral (5) can be easily evaluated in terms of F(a,{:J) , which is related to the \"first~order transition curves\" by formula (2). The derivation proceeds as follows: It can be verified that (j2 --[F(a,{:J) (a - {J) ] (ja8p = a 2F(a,p) (a _ (3) + aF(a,{:J) oa a/3 ap _aF~(:.....-a.:!....J3.:.-) . (6) da Using Eqs. (3) and (6), we find 2jt(a,/3) (a _ (3) = 8F(a.{3) _ aF(a,/J) 8P oa (j2 - -- [F(a.{3)(a - {3) ]. (7) aa 8{3 Now, consider a triangle T(u+,u_) swept (see Fig. 5) dur~ ing the input increase from u _ to u +. According to Eq. (5), such input variation is associated with the losses Q(IL,U+) = f f p,(a,/3)(a - (3)da d/3 T(,,+,u ,.) = i~+ ([ jt(a,{J)(a - /3) d/3 )da = iU ,+ (Lu + p(a,/3)(a -fJ)da )d/3. (8) Substituting Eq. (7) into Eq. (8), performing the integra tion and taking into account that F(a,a) = 0, after simple transformations we find 1 rru , lU' Q(u_,u+) = - 2\" Uu_ F(a,u_ )da + \"_ F(u+.{3)d{3 - (u+ - u_ )F(U+,U_\u00bb) . (9) It can be shown that the derived expressions for hysteretic energy losses are consistent with the classical result: the hys teretic energy losses for any cyclic input variation equal the area enclosed by the loop resulting from the cyclic input 3912 J"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003734_ip-b:19830027-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003734_ip-b:19830027-Figure3-1.png",
+ "caption": "Fig. 3 Travelling-rotating wave",
+ "texts": [
+ " I (4) After trigonometric transformation, eqns. 3 and 4 are [5]: Js x(t, z) = X I X \\js xmM exp [j(u>t + (3mz)} (5) i 1 The kl harmonic of function 5 represents two waves travelling in the z-direction with different speeds. The kl harmonic of function 6 consists of two waves travelling with the same speed in the x-direction and with equal but opposite directions along the z-axis. This means that these latter two waves are travelling rotating waves moving helically on the cylindrical surface of the stator (Fig. 3.). If the rotor moves in a helical fashion, then the slip of the rotor related to the kl harmonic of the magnetic field is expressed by the equation ktt \" vxk vzli (7) i l k where vx and vz are rotor speeds in the x-and z-directions and vxk = \u2014 2rxfe/and vzU = \u2014 2Te/,/are speeds of the kl harmonic in the x- and z-directions. Eqn. 7 can be derived in two different ways. One of them, given in Reference 1, is as follows: If the rotor moves with asynchronous speed in relation to the kith field harmonic, it means that the field of kith harmonic varies for each point on the rotor surface",
+ " 12, we obtain vz + vx tan 7 (13) (14) Ski = 1 ~ (15) (16) (17) vzl Since tgy = vzl/vxk, eqn. 17 finally takes the form of eqn. 7. Eqn. 7 can also be obtained by starting with the following definition of the rotary-linear slip: s = 1 (18) where vki is the synchronous speed in the direction of the rotor motion (Fig. 5). Eqn. 7 indicates that the slip depends on two components of the rotor speed. If one of them is zero, then the slip takes the form well known in the theory of conventional motors. Considering the direction of the travelling rotating wave speed (Fig. 3), it is noticed that a change of the TX1 or TZ1 value causes a change of the direction of its movement. If we put Txi ->\u00b0\u00b0 in eqn. 6, we obtain a travelling wave, and if TZI ~*\"\u00b0\u00b0. w e n a v e a rotating wave. That means that the description of a helical movement is more general than that of a travelling or a rotating wave. The remaining analysis will hence be concerned with the helical field. At any time we can consider the travelling field of the linear armature by putting ' xl 2.2 Electromagnetic-field equations To define the electromagnetic field in the RLIM, Maxwell's equations have been used"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002271_robot.1988.12256-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002271_robot.1988.12256-Figure4-1.png",
+ "caption": "Fig. 4",
+ "texts": [
+ " The robot hand has three 3 DOF fingers driven by nine DC servo motors. This hand was developed to research coordinative manipulation by multiple robotic mechanisms [8]. Since precise force control of each finger is required, simple gear reduction and transmission system were adopted. The reduction ratio of each motor is only sixteen. By using the five bar closed link mechanism and a special transmission, the finger structure was simplified as shown in Fig.3, and all the motors were located in the wrist portion. The transmission is shown in Fig.4. The dynamics of the closed link finger mechanism was computed using the computational scheme proposed in section 2. The coordinate frames and the corresponding open link tree structural mechanism are shown in FigS. The coordinate frames were defined according to the Denavit-Hartenberg notation [9]. O i indicates the rotational angle along the z axis of the (i-1)-th coordinate frame. e,, e,, and O3 axes are the actuated joints. Accordingly, 91 = ( e l 82 83)T (27) From the visual inspection, 8, and 8, are represented as the function of e,, \u20acI2, and 8, as follows: e, = 8,- e3 1357 1 0 0 0 1 0 w = 0 0 1 0 1 -1 0 -1 1 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003974_tia.2005.863911-Figure11-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003974_tia.2005.863911-Figure11-1.png",
+ "caption": "Fig. 11. Shaft radial speed feedback.",
+ "texts": [
+ " 10 shows the experimental results when radial force step disturbance is added as Fext in \u03b2-axis as shown in Fig. 7. The case of H = 0 is a conventional system. For the proposed radial force feedback system, the value of H is set to 10. The gains of PID controller are the same in the both systems. It is seen that the response of the proposed radial force feedback system is 200 \u00b5s faster than the response of the conventional system. It is also found that the proposed radial force feedback has better damping in radial magnetic suspension. Fig. 11 shows the proposed system of radial speed feedback, in addition to radial force feedback. The detected radial force is divided by the shaft weight, and then it is integrated. Thus, the shaft radial speed v\u0302\u03b2 is obtained. The radial speed is added to the output of the derivative controller in a PID controller. The block H2 is added for radial speed feedback loop. It is to be noted that when H2 = 0, then effect of the radial speed feedback is zero. As the H2 is increased, the effects of shaft speed feedback are increased"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000454_s0191-8141(99)00079-6-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000454_s0191-8141(99)00079-6-Figure7-1.png",
+ "caption": "Fig. 7. Distances used to measure the \u00aet error. (a) Along the y-axis. (b) Along the x-axis.",
+ "texts": [
+ " (4a) and (4b), the \u00aetting function that passes through the point x0=2,yM of the natural fold is de\u00aened by a C value given by: C y0 \u00ff yM 1\u00ff 3 p 2 : 9 The \u00aetting method by coincidence of the functions using their x-middle point is easy to apply and o ers a satisfactory approximation to the natural fold pro\u00aeles. The approximation of natural fold pro\u00aeles to theoretical functions involves a degree of mis\u00aet that must be evaluated in order to know the accuracy of the \u00aetting methods. If yi f xi is the value of the \u00aetting function [Eqs. (1), (3), (4a) and (4b) or Eq. (5)] for xi, and x1,z1 , x2,z2 , . . . , xN,zN are points of the natural fold pro\u00aele (Fig. 7a), the absolute rms error along the y-axis is given by ey 1 N XN i 1 zi \u00ff yi 2 vuut 10 and the relative error expressed as a percentage is ey,r 100 ey y0 : 11 Similarly, if zi g xi f x 0i is the value of the function de\u00aened from the natural fold for xi and of the \u00aetting function for x 0 i (Fig. 7b), the error along the x- axis is given by ex 1 N XN i 1 x 0i \u00ff xi 2 vuut 12 where x 0 i f \u00ff1 zi . The corresponding relative error expressed as a percentage is ex,r 100 ex x0 : 13 From Eqs. (11) and (13), a total relative average error can be de\u00aened as e r ex,r ey,r =2: 14 The \u00aetting error a ects several geometrical parameters of the analysed fold. In the case of alloclinal folds, one of these parameters is the maximum dip (Fig. 1a), which, in general, is di erent in the natural fold pro\u00aele and the \u00aetted curve"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001220_rob.10067-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001220_rob.10067-Figure4-1.png",
+ "caption": "Figure 4. A thirty-link manipulator reaching a point inside a tunnel.",
+ "texts": [
+ " The obstacle is represented by 14 panels (m 14). The manipulator has nine links and each link is 1.0 m long. The start and the goal points are located at (3.0, 0.8, 0.8) and (2.0, 3.0, 1.5), respectively. A value of Vj 8 m/s was determined for all panels. It can be seen that the shape of the obstacles does not stop the manipulator from reaching its goal successfully. Example 3: As the third example, we model a more complicated situation, where a 30-link manipulator (with link lengths of 0.25 m) must reach a goal inside a tunnel (Figure 4). Since the obstacle surfaces are close together in the tunnel example, each tunnel surface was discretized into a number of smaller panels (m 12) in order to have more control on the safe path by changing the value of Vj\u2019s (Vj 14 m/s). For more clarity, the panels\u2019 boundary lines are not shown in the figure. The start and the goal points are located at (0.5, 1.0, 0.0) and (2.0, 2.5, 2.5), respectively. Figure 4 shows the manipulator in four successive configurations while it is reaching the specified goal in the tunnel. The manipulator is able to avoid the tunnel surfaces and reach the goal successfully. Example 4: In our last example, we consider a 3D cluttered environment with several obstacles of different shapes and sizes. The obstacles are represented by 72 panels (m 72). A 22-link manipulator with link lengths of 0.6 m is modeled. The start and the goal points are located at (0.2, 1.0, 1.2) and (2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002579_robot.1997.606743-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002579_robot.1997.606743-Figure1-1.png",
+ "caption": "Figure 1: 2R free-joint manipulator",
+ "texts": [
+ " The equation represents an autonomous system without E , the amplitude of the perturbation. It implies that the feature of the behavior with a small perturbation is determined by the averaged dynamics independently of E . Since it is necessary to discuss the characteristic of the solution trajectory of the averaged dynamics concretely, we will present control problems of 2R and 3R free-joint manipulators in the following sections. 3 2R free-joint manipulator 3.1 Analysis via the averaging method Figure 1 shows a free-joint manipulator with the first joint actuated and the second joint free, which resides in the horizontal plane. The simplified dynamics is represented by $2 = -(I + ncose2)i1 - nsin02 . (ill2 (7) where Oi denotes a relative angle of the i-th joint and, n = m 2 and I2 denote the mass and inertia of the second link, respectively, and I1 denotes the length of the i-th link and s 2 denotes the length from the i-th joint to the center of mass of the i-th link, as shown in Fig. 1. def m 2 l l s 2 \" 2 + I2 ' With the periodic input and the substitution as in the previous section, the system is represented by the following equation only for the second joint. 2 (8) q = Ep i = -(l+ncosq)f;(t) - ~ n s i n q . ( f & ( t ) ) where p and q denote & / E and 0 2 , respectively. Since its non-perturbed solution is q = qo and p = po - (1 + n cos qo) f&( t ) , the transformation is given by $ = p + ( l + n c o s q ) f & ( t ) (9) The standard form is obtained from Eqs.(8) and (9). q = E(4 - (1 + ncosq)f&(t)) 4 = E +sin q j k ( t> + $ sin 2 q "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002222_1.533555-Figure11-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002222_1.533555-Figure11-1.png",
+ "caption": "Fig. 11 Meshing pinion gear teeth",
+ "texts": [
+ " The surface equation is a function of three variables ac , a3 , and Sr , respectively the cutter angular position, the work roll angle, and the position of a point along the cutter blade edge: S5 f ~ac ,a3! (A2) The position of any point P on the generated tooth surface is therefore defined by a combination (ac ,a3). The solution to Eq. ~A2! is a series of contact points between the cutter blade edge and the work describing a line along the path of the cutter edge defined by angle ac . The bounded envelope, along the work roll angle a3 , of a series of such lines in the work reference frame X, gives the generated pinion tooth shown in Fig. 11. Fig. 11 also shows a nongenerated gear tooth. A Newton\u2013Raphson iterative method is used to numerically solve Eq. ~A2!. rom: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 01/27/20 A.3 Tooth Contact Analysis. First pioneered by The Gleason Works in the early sixties, Tooth Contact Analysis is the numerical process by which the kinematic characteristics of a tooth pair, such as Transmission Error and bearing pattern, are obtained. To obtain such characteristics, several contact points must be obtained on the tooth flanks. While several numerical solutions have been proposed in the literature, the basic contact conditions are ~Fig. 11!: Z\u0304P5Z\u0304G (43) N\u0304P5N\u0304G where Z\u0304 are the tooth flank coordinates and N\u0304 are the tooth flank normals, respectively, for the pinion and gear members, expressed in a common reference frame. Equation ~A3! yields five equations, for six unknowns, which may be solved using a Newton\u2013Raphson or similar iterative algorithm. Transmission Error is obtained as the difference in the calculated position of the gear member in reference to its theoretical position: dw35w32Q3mg (A4) where dw3 is the Transmission Error, w3 is the calculated position of the gear member, Q3 is the calculated position of the pinion member, and mg is the speed ratio"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002572_robot.1996.506595-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002572_robot.1996.506595-Figure2-1.png",
+ "caption": "Fig. 2 Three link manipulator system",
+ "texts": [
+ "(21). Where d\"'j&/dt = O b j WT. Using a negative constant kl, y is given by (49) [I] Set i ::= 0. [2] Calculate variations AB, Aq by substituting values of joint variables, B j , qi and variations of task variables, AobjrT, Aobj$T into eq.(48). [3] Set (50) 0i+l = 0, + A0 qi+l = qi + Aq [4) Replace &,q; with B;+l,q;+l. Go back to [2]. 6 Examples First, tlhe proposed algorithm is applied to the cooperative motion planning for two planar manipulators. Each manipulator has three links. As shown in Fig.2, the manipulator-A holds the object rigidly and the manipulator-B executes the task for the object with the tool. The specified task is that the tool moves along the circular arc by 90 degrees as shown in Fig.2. The radius of the obstacle is O.l[m] and in the position (0.8, 1.1). Fig.3 shows the motion path without considering collisions avoidance (y = 0 in eq.(48)). In this case, the sum of squares of variations of joint variables, S, is 0.0025. The path for the case when the position and the orientation of the object are fixed has 0.0549 as the value of S. In the case of Fig.3, total value of variations of joint variables becomes smaller by moving the manipulator-A. From this result the meaning of the pseudo inverse is understood"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002129_09500830210128074-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002129_09500830210128074-Figure4-1.png",
+ "caption": "Figure 4. A possible application is sketched. (a) A bifurcation in the tube where a 2\u00b11\u00b11 structure is propagated (from left to right) leads to two channels of bamboo structure, the bubbles close to the top of the tube going in the upper channel. (b) If a magnet (shown in black) generates a 180\u00b0 twist of the 2\u00b11\u00b11 before the bifurcation, the bubbles will go in the opposite channel compared with (a).",
+ "texts": [],
+ "surrounding_texts": [
+ "Thanks are due to Jean-Claude Bacri and to Nicolas Rivier for stimulating discussions and Valerie Cabuil for providing the ferro\u00afuid."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002755_j.triboint.2004.12.003-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002755_j.triboint.2004.12.003-Figure1-1.png",
+ "caption": "Fig. 1. Diagram of lip seal and detail of A.",
+ "texts": [
+ " the global TEHD behaviour of the lip seals using modeling of the structures of the lip very close to reality [19]. Three mathematical models of roughness are considered and the influence on features such as the average and minimal thickness, reverse pumping, power loss and the average temperature reached is analyzed. Taking its geometric shape, lip angle and the spring location into account, the radial flexure of the lip produces an asymmetric distribution of the contact pressure ps leading to a strong rise on the lubricant side and a smooth decrease on the air side (Fig. 1). A new and original approach was presented in a previous paper [19]. The compliant part of the seal is not assumed to have a totally elastic axisymmetric behavior; it is divided into two parts with different mechanical behaviors. We consider the following hypothesis: the lip seal is perfectly elastic, the rotating shaft perfectly smooth and the seal perfectly centered (no whipping). Nomenclature b cell length representing the lip seal (mm) Cij compliance matrix relative to pressure (mm/Pa) Cp specific heat (J/kg K) D universal parameter (pressure in the active zone and replenishment in the inactive zone) Def distortion of the lip due to the pressure (mm) Ej(Ue) functional value at node j of element Ue Eref Young\u2019s modulus at the reference temperature (N/mm2) f(x, y) analytical profile of the lip surface defect (mm) F control function (FZ1 in the active zone; FZ0 in the inactive zone) FL applied load (N) h lubricant film thickness (mm) h0 defect amplitude on the lip surface (mm) hc heat transfer coefficient of oil (W/m2 K) hm elastic contribution to the thickness of the film L shaft longer (mm) nx, ny number of periods of the defect on the lip surface for (x, y) direction P hydrodynamic pressure (Pa) pi nodal pressure (Pa) Q pumping rate (mm3/s) r replenishment (mm) R shaft radius (mm) S cross surface of shaft (mm2) T lip temperature (K) Tref reference temperature (K) Tki compliance matrix relative to the shearing (mm/Pa) DT TKTref (K) U shaft linear speed (mm/s) W, W* weight functions x circumferential coordinate (mm) y axial coordinate (mm) xc, yc location of centre of asperity (mm) a thermoviscosity coefficient (KK1) b thermoelasticity coefficient of Young\u2019s modulus of nitrile rubber (KK1) d circumferential displacement due to shearing (mm) h interference (mm) k heat conductivity (W/m K) l defect wave length on the lip surface (mm) mref lubricant viscosity at the reference temperature (Pa s) r density of lubricant-gas mixture (kg/m3) r0 density of the lubricant (kg/m3) txyi local stress shearing (Pa) The steady state Reynolds equation for an isoviscous case is: v vx rh3 vp vx C v vy rh3 vp vy Z 6mU vrh vx (1) This equation is solved, coupled (through the elasticity matrix) to the elastic behavior of the seal, by controlling the cavitation that must be checked for the active zones (zones under pressure)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002374_naecon.1994.332886-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002374_naecon.1994.332886-Figure6-1.png",
+ "caption": "Figure 6",
+ "texts": [],
+ "surrounding_texts": [
+ "architecture for each type i s included later in this paper.\nThroughout the development of the several PBW systems described above, the incorporation of Fly-ByWire technology into the servo control scheme has yielded additional advantages in maintainability and control accuracy. In additlon, Fly-By-Light control has been developed, built and tested by Lucas in aircraft flight control systems and has been evaluated for use in future PBW systems.\nDescriptions of previous and ongoing PBW program experience are included in this paper.\nlAPTM\nTECHNICAL DESCRIPTION The lAPTM i s constructed of (4) basic elements: a hydraulic servopump. an electric motor, a hydraulic actuator, and a closed loop control system providing actuator positioning in response to an input command. Several variations of these individual elements can provide wide adaptability of the system and have been used in the design and development of various actuation packages. Figure 2 depicts an lAPTM system schematic incorporating electronic control signalling.\nEach of the major components and their variations i s described below:\nSERVOPUMP - The servopump utilized in the Lucas lAPTM i s an over-center type, variable displacement, variable flow direction, piston pump capable of producing actuator control authority in response to control error signals. The servopump element i s a high efficiency, high reliability, splayed axis type piston pump rotating at a fixed speed. Flow direction and rate is accomplished through the positioning of variable angle swashplate. The positioning of the swashplate i s governed by an internal control loop\nwhich receives the control error input, measures swashplate position and produces control flow to one of two stroke control pistons. An integral fixed displacement boost pump, used to supply control flow and maintain minimum actuator pressure can also be used. Maximum discharge pressure capability of the servopump has been well proven at 5000 psi. A schematic of the servopump is shown in Figure 3.\nELECTRIC MOTOR - Since the servo control of the lAPTM i s performed within the servopump detailed above, the only requirement for the electric motor i s to rotate the servopump at a fixed speed and direction. This requirement can be accomplished with either AC or DC motors. The preferred choice i s AC as this provides a simpler, more readily available design. In addition, AC power minimizes EM1 generation and it's possible degradation of control signalling. In an aircraft system where DC motors are preferred, the lAPTM can be configured with a brushless DC motor and motor controller designed to maintain a relatively fixed speed.\nHYDRAULIC ACTUATOR - The hydraulic actuator incorporated in the lAPTM can be of various configurations. Linear or rotary types can be used as well as dual or tandem configurations. To keep system size and weight to a minimum, equal area actuators are preferred to negate the need for large capacity, fluid storage areas. Position feedback sensors are commonly incorporated into the actuator design during initial fabrication. These sensors can be made with multiple channels as necessary to achieve redundancy goals. The basic actuator design i s very similar to that commonly used in aircraft actuation systems with design improvements added to achieve longer seal l i fe and lower seal leakage. In addition, high pressure technology (up to 5000 psi) can be utilized to reduce system weight and size.\nCONTROL SYSTEM - The basic control function of the lAPTM i s to position an aircraft flight control surface (or utility feature) to a specific location in response to a position command. This positioning must be done accurately, repeatability, efficiently and\n1339",
+ "with maximum stability. The control system of the lAPTM compares the input command to a position feedback of the actuator and produces an error signal to the pump servocontrol system. As the actuator responds and moves toward the commanded position the error signal decreases, providing stable positioning. An internal control function in the pump servo control system acts as a \"loop within a loop\" to provide stable pump response and control. A schematic of a representative control loop i s shown in Figure 4.\nDESIGN EVOLUTION The design evolution of the Lucas lAPTM dates back to the early 1980's and includes design progression in many of the system components. A chronology is listed below:\nMODEL 91E01-1A (1980-1982) This demonstrator system was developed for a nose wheel steering application. To reduce development costs and take advantage of proven, high reliability components, the system was constructed from Lucas's splayed axis piston pump technology previously used for Variable Exhaust Nozzle (VEN) actuation applications on fighter aircraft engines. The unit was a tandem system utilizing two independent channels. The control system was completely mechanical. An input bellcrank was used to command actuator position. This bellcrank acted upon a four bar linkage which received mechanical feedback of actuator position. This mechanism produced movement of a hydraulic shuttle valve, providing servo control. The system was subjected to limited bench testing. A photograph of the package i s shown in Figure 5.\nSYSTEM ADVANCES - Dual channel system provided redundancy. Used 115VAC 400Hz power.\nMODEL 91E03 (1983 - 1988) This demonstrator unit was designed to be used in a nose wheel steering power-by-wire demonstration system. While similar in design to the model 91E01 described above, the control system was modified to incorporate an electrical input and feedback signal. A simple electronic control circuit resolved these signals into a command voltage to a proportional solenoid. The solenoid input the \"error\" signal mechanically into a flow control servovalve. The lAPTM was a single channel design and completed extensive bench testing. A photograph of Model 91E03 system i s shown in Fkure 6.\nSYSTEM ADVANCES - The incorporation of an electric control loop reduces backlash of mechanical input and feedback linkage.\nMODEL 91E05 - (1990 - 1993) This lAPTM was developed specifically for an aircraft rudder application. The system incorporated an external Electronic Control Unit (ECU) to perform the control function. The ECU is a micro-processor driven unit which accepts not only input and feedback signals but Input/Output commands for discrete monitoring and failsafe capability. The control mode i s truly Fly-By-Wire (FBW) The system i s dual channel with independent command, feedback and error circuits for each channel. Signal averaging was incorporated to minimize force fight between channels. This minimum force fight was also accomplished by independent pump control gain setting to match pump performance. The actuation package also incorporated passive/active heat dissipation and overheat protection. The system was extensively bench tested and accomplished limited flight testing. A photograph of the system is shown in Figure 7.\nSYSTEM ADVANCES - The ECU control system allowed for increased performance capability. Dual channel redundancy was attained with minimal force fight. The system thermal performance was acceptable throughout ground and flight testing.\n1340",
+ "SYSTEM ADVANCES - The incorporation of differential pressure as a performance monitor will allow for very accurate system matching of dual channels of a system. Power and heat efficiency are greatly improved over previous packages and allow for incorporation into the aircraft without the addition of power generating capacity. A MIL-STD-1553 communication network allows for remote system data collection, evaluation and fail safe system shutdown.\nFUTURE: DEVELOPMENT Future design advances planned for the lAPTM include:\nMODEL 91E06/9lE07/91E08 (1992 -) These three lAPTM systems are part of an electric spoiler and aileron aircraft demonstration program. The actuation packages are all dual channel systems and are very slmllar In deslgn. As in the Model 91E05 listed above force fight i s minimized through the use of signal averaging, In addition, differential pressure transducers are used to measure actual channel performance against predicted performance and the error signal i s \"trimmed\" to further reduce force fight. The electric drive motors contain a power factor correction feature for optimal motor performance throughout the various operating modes. Active air cooling i s employed to provide maximum heat dissipation for the actuation packages. A Central Interface Unit (CIU) i s included in the aircraft conversion to provide for maintenance data collection from each actuation package individually and provide a single maintenance interface. In addition, the CIU monitors spoiler position to greatly diminish the possibility of aircraft asymmetry. The overall aircraft electric actuation system provides system operational status and i s controlled through the existing aircraft's pilot interface. A photograph of the actuation package is shown in Figure 8. .\nEfficiency upgrade through elimination of hydraulic pump control servo loop and incorporation of electrically driven pump servo control Adaptation to 270 VDC power for use in future aircraft incorporating 270 VDC power generation.\nmicrocircuitry development Incorporation of extensive Fly-By-Light experience into the lAPTM control systems to adapt with future aircraft ARINC 629 or MIL-STD-1773 information networks.\nWeight/Size reduction through ECU\nThese design improvements are part of ongoing and planned development programs at Lucas to improve the IAPTM.\nEMA\nTECHNICAL DESC RI PTlO N The Lucas Electromechanical Actuator is a Power-ByWire device utilizing no hydraulic elements. The control \"loop within a loop\" i s similar to the lAPTM but i s accomplished electronically. A functional diagram of the EMA i s shown in Figure 9.\nThe EMA and i s comprised of two major components:\n1341"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001194_analsci.14.203-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001194_analsci.14.203-Figure3-1.png",
+ "caption": "Fig. 3 Variation of the CL intensity with the 8-quinolinol concentration used for the Fe(oxine)3 extraction.",
+ "texts": [
+ " 2, increasing the R value along with a decrease in the CTAC content at a constant amount of water in the reversed micellar solution caused an increase in the CL emission. Further, the intensity reached a maximum at around 0.15 M CTAC and an R of 22.2, which were chosen to be optimal. Beyond the respective optimized levels, the relatively high viscosity of the luminescent reagent solution makes it difficult to obtain sharp and reproducible signals, since rapid mixing with the Fe(oxine)3 solution is hampered in the flow cell. As shown in Fig. 3, the CL intensity increased along with an increase in the concentration of oxine in an aqueous solution which was mixed with the aqueous sample solution of iron(III) for the extraction of the Fe(oxine)3 complex into chloroform. It was observed that a 1.0\u00d710\u20133 M oxine concentration was optimal and a maximum CL intensity was attained at around the concentration. When an aqueous blank solution was used in place of the aqueous sample solution of iron(III), some CL emission resulted, which is presumed to have been caused by the partial extraction of oxine molecules into chloroform"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000909_027836499901800506-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000909_027836499901800506-Figure2-1.png",
+ "caption": "Fig. 2. Unit vectors relating to the contact points.",
+ "texts": [
+ " If a disturbance force (Fh) and a torque (Th) of a unit value directed along the axes of the reference system were to be exerted in turn on the object, the forces at the contact points would have to verify the following relations to ensure equilibrium: Fh + n\u2211 p=1 ( ap,hvN(p) + bp,hvT(p) ) = 0, (3.1) Th + n\u2211 p=1 (P(p) \u2212 C)3 ( ap,hvN(p) + bp,hvT(p) ) = 0, (3.2) |bp,h| \u2264 f ap,h, p = 1, 2, . . . , n, (3.3) ap,h \u2265 0, p = 1, 2, . . . , n, (3.4) (3) where ap,h and bp,h indicate the normal force (direction vN(p) ) and the tangential force (direction vT(p) ) respectively, at the generic contact point P(P ) (Fig. 2), and f indicates the static friction coefficient. With h = 1, 2, . . . , 6 and the unit vectors F1 = i(N); F2 = j(N); F3 = \u2212i(N); F4 = \u2212j(N); F5 = 0(N); F6 = 0(N); while T5 = k(Nm); T6 = \u2212k(Nm); and Th = 0(Nm) for 1 \u2264 h \u2264 4. Equations (3.1) and (3.2) are the equations for object equilibrium; eq. (3.3) expresses the relations between the normal and tangential components of the contact force (hard finger), and eq. (3.4) defines the presence of unilateral constraints between the fingers and the object"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003364_0020-7403(88)90076-8-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003364_0020-7403(88)90076-8-Figure2-1.png",
+ "caption": "FIG. 2. Discretized model of surface tractions:",
+ "texts": [
+ " In reworking the problem of tractive rolling of homogeneous cylinders [4], we were able to use an accurate integral equation approach. For the tyre problem the complexity of the kernels precludes this and accordingly the method of solution employed here is similar to that of Bentall and Johnson [5] where the surface tractions are modelled by piece-wise linear distributions. Direct and shear tractions in the contact patch are each represented by 2 S - 1 overlapping triangles with equal bases of width 2a/S , as shown in Fig. 2. The heights of the nth triangles are p, and q,, which represent the magnitudes of the direct and shear tractions respectively at x = na/S. We now write down the relative vertical and horizontal surface displacements, v(m) and u(m), at a point x = m a / S (Iml ~< N) due to the total normal and tangential forces exerted [5]: v(m) 4 ( 1 - v 2) 2B s-1 - - - - - ~. [P.IA(n -- m)+ Q.Ia(n-- m)] (3) a xE Z n=-(s- 1) u(m) 4(1-v2)2B s-1 . . . . ~. [ - - P . I B ( n - - m ) -- Q. lc(n - m)], (4) a ~E Z . = - ( s - u where P"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002509_i2002-10164-3-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002509_i2002-10164-3-Figure8-1.png",
+ "caption": "Fig. 8. Geometry of the grooved surface. Aw and Pw are, respectively, the amplitude and the period of the grooves.",
+ "texts": [
+ " In the former case of the non-uniform planar anchoring, the directors are assumed to be oriented tangentially to the grooves but without any overall preferred orientation while in the latter uniform case, there is an average preferred molecular direction. The fixed orientation of the nematic director on the grooves is given by n(yw (x) , x) = (cos \u03b8 cos\u03c6, cos \u03b8 sin\u03c6, sin \u03b8) , (15) where the zenithal angle \u03b8 gives the rotation around the z-axis and the azimuthal angle \u03c6 gives the rotation around the y-axis (Fig. 8). In this case, the azimuthal angle \u03c6 takes random values between \u2212\u03c0/2 and \u03c0/2 on the grooved surface, corresponding to surface anchoring case (1). The helix vector at the wall Nw is along k and is hence inhomogeneous: Nw = Nw(x). In addition, \u03c6 is random and the helices are out-of-phase since \u03c6 = \u03c6(x). Figure 9a-c shows a time series visualization of the computed tensor field M(x, y, t) describing the propagation of order in the case where the azimuthal angle \u03c6 takes random values between \u2212\u03c0/2 and \u03c0/2 on the grooved surface"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003465_00423110600871533-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003465_00423110600871533-Figure1-1.png",
+ "caption": "Figure 1. A sketch plan \u2013 dimensions are not realistic \u2013 of a moveable frog (a) and its CAD model (b). Both views are set in a straight direction configuration.",
+ "texts": [
+ " The changing rail profile is taken into account via an interpolation process function of the distance. In practice, the handling of varying rail profiles consists of adding a dimension to contact tables. Guidelines for meshing are given. A case study is conducted. The benefit of the method is demonstrated as soon as it is required to compute stresses accurately. Keywords: Turnouts; Wheel\u2013rail contact forces; Multi-body simulations Moveable frogs are devices that allow vehicles to run on turnouts in high-speed conditions. Such a device is sketched in figure 1(a). Its design enables the wheel to roll on a continuous running surface. As a result, dynamic effects are relatively weak. Figure 1(b) shows a CAD model. The perspective has been cancelled to make it more informative: the longitudinal dimension is about 20 m long though the lateral one is about 0.1 m. The critical zone is the transition between the wing rail and the frog. A turnout\u2019s crossing has already been studied with multi-Hertzian methods [1], and various commercial packages possess functionalities that enable the study of it [2]. However, the results are usually expressed as forces or accelerations. In a rolling-contact fatigue context, it is often required to get more accurate results such as contact stresses",
+ " But, interpolating data tables is not exactly the same as building tables from interpolated profiles. Caution must then be exercised when defining the strip discretization in order to avoid unintended results because of the interpolation process. Furthermore, it is necessary to keep some continuity between strips: from figure 3(b), it is obvious that if strip j is on the tread in cross-section i, and on the flange in cross-section i + 1, the interpolated strip will be twisted leading to uncertain results. Apart from the gap between the wing rail and the frog toe (see figure 1), transitions between strips should be smooth, and the best strategy for avoiding poor results because of meshing consists of having the same strip following the wheel path in a given position, say the centred position. For the other strips, twisted transitions should be prohibited. In other words, strips from one profile to another should have the same angle. Prior to the simulation, several static analyses are made on each profile for a set of relative wheel positions, supplying locations where contact is likely to occur. Strips are concentrated on these locations and follow the centred wheel trajectory. This has the double advantage of minimizing interpolation artefacts and increasing accuracy as only the potential contact areas are finely meshed. 4. Case study 4.1 Model Figure 4(a) shows a mesh of a moveable frog, derived from a CAD model, similar to the one shown in figure 1(b). Strips limits are longitudinal lines, and cross-sections, transversal ones. Perspective effects have been intentionally removed, as the tread is \u223c0.1 m wide and the view spans along 20 m. Strip widths vary between 0.04 and 2 mm. Cross-sections are selected according to two criteria: on one hand, they are associated to varying rail profiles and, on the other hand, to locations where contact will exhibit jumps and transitions. The latter type of cross-section is selected during the quoted static analyses performed prior to the simulation. In the present case, the mesh is concentrated on relatively thin zones, as theoretical profiles are concerned. In worn profiles, contact zones would be more spread over the rail surface. 4.2 Results Figure 4(b) shows a typical result from a dynamic simulation: the black area is the rolling trace of the wheel on the rail when the vehicle runs straightforward (figure 1(a)) on a tangent track without additional irregularities. The model has 250 strips per cross-section and 16 crosssections. The ratio between the computer time and the real time is about 10 on a 2.5 GHz processor PC. Figure 5 shows at the top the Q vertical force (expressed in kN) applied on the rail when the frog is crossed. Figure 5 shows at the bottom, the maximum contact pressure pmax (in MPa). The head of the frog is indicated by a vertical line, and the jump between the wing rail and the frog by a dashed vertical line"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.16-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.16-1.png",
+ "caption": "Figure 1.16. Pitch triangle for a circular helix.",
+ "texts": [
+ " Hence, the speed also is constant: k \u00b7 t =cosy= A(R2w 2 + A2 ) - 112 , ( 1.92) ( 1.93) ( 1.94) which is a constant. Thus, the tangent at each point on a circular helix makes a constant angle with its axis. This result is more useful than ( 1.94) suggests. More generally, the tangent line property shows that when a helix is rolled on a plane, in one revolution its tangent traces a straight line that forms the hypotenuse of a right triangle of altitude p, the pitch of the helix, and base 2nR as shown in Fig. 1.16. This triangle is called the pitch triangle. When a particle moves on a circular helix, it rotates through an angle wt = O(t) about the helix axis, as described in Fig. 1.2, and it traces in the xy plane a circular arc of length RO(t) as it advances a distance z(t) along that axis. We see from the pitch triangle that tan y = 2nR/p = RO(t)/z(t). Hence, the axial advance along a circular helix is proportional to the angle of rotation about its axis, Kinematics of a Particle 39 and the invariant tangent angle y of a circular helix is determined uniquely by the ratio of the circumference of its base circle to its pitch: tan y = 2nRjp",
+ " The second example will demonstrate three methods that usc cylindrical coordinates to obtain the same problem solution in slightly different ways, one method being the easy direct application of ( 4.59) and ( 4.60 ). Afterwards, two further applications that employ cylindrical coordinates to create meaningful results will be presented. Example 4.10. An electron E moves in a preferred frame cP with a con stant speed v along a cylindrical helix described in cylindrical coordinates by the equations r =a, a constant, and 2nz = pl/J, where p is the constant pitch. [See (1.95) and Fig. 1.16] Find the absolute acceleration of the electron. Solution. To take advantage of the assigned constant speed condition, we first compute the velocity of E. With r =a, f = 0, and i = p~/2n, direct usc of ( 4.59) yields the absolute velocity of E: ( 4.64a) wherein c = 2na. Since the speed I vEl = v is constant, ( 4.64a) shows that the angular speed ~ has the constant value . v [ (p)21-l/2 \u00a2=- 1+- . iJ. c (4.64b) The acceleration may now be obtained easily from (4.60). Because Motion Referred to a Moving Reference Frame and Relative Motion 271 r=fP=z=O, (4"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002381_robot.2001.933052-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002381_robot.2001.933052-Figure5-1.png",
+ "caption": "Figure 5: Fitting into virtual joint model (n=3)",
+ "texts": [
+ " 5 Lumped State Estimation of Virtual Joint Model In this section, we describe a method to transform the distributed state variables of flexible links into lumped state variables of the virtual joint model. When we get the lumped state variables by the proposed method, it is also possible to identify physical parameters of the dynamic model. 5.1 Transformation into Lumped State Variables Here we set the position of virtual passive joints and link tip as the representative points of link i. ( t ) , . . . , zj3n+l(t) denote the position of representative points of link i. As shown in Fig.5, the representative point \u2018 p j ( t ) = [z&.. ,,Z@yj]T (3 = 2 , . . . , n + 1) is determined to locate on the link i shape function yz(z,, t ) . First, \u2018p1( t ) is given by ip,(t) = [ ] (9) then, i@j(t) ( j = 2 , . . . , n + 1) is determined as the point satisfying the following simultaneous equations. From these representative points, the virtual pas- sive joint angles 4,(t) are given by FFT niiulyzcr li=il The virtual passive joint velocity $,(t) = is estimated by numerical differen- The transformation matrix '+lT, from E, to E,+l [&I, &, "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure5-1.png",
+ "caption": "Figure 5. A symmetrical dynamic system with two DOFs and its graph model: (a) planar frame; and (b) the corresponded mass\u2013spring system and its graph model.",
+ "texts": [
+ " Then the efficiency of group-theoretical approach is highlighted though comparison of the results to those of the algebraic methods, for problems with hyper symmetry. The motion associated with a vibrating mechanical system with n degrees of freedom (DOFs) can be expressed in terms of the well-known generalized eigenvalue equation Ku= 2Mu (14) in which M is an n \u00d7 n symmetric, positive semi-definite mass matrix, K is an n \u00d7 n, symmetric stiffness matrix, is a frequency and u is a corresponding mode shape. The mathematical model of a dynamic system consists of masses and springs. A simple symmetric mass\u2013spring system is shown in Figure 5(b), which can be assumed as the mechanical model of the free vibration of planar frame shown in Figure 5(a). The masses and the shear stiffness of each storey are presented in the figure. This is a problem with two DOFs (n = 2). In any mass\u2013spring Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm system, the masses are connected by means of springs. As the mathematical model, a weighted graph can be defined as follows [11]. 1. The supports in the mathematical model are associated with neutral nodes in the graph. 2. For each mass, a node of graph is associated and its weight is taken as the magnitude of the mass",
+ " Comparing the correspondence between the stiffness matrix of the mass\u2013spring system and the Laplacian matrix of its graph model, one can obviously show the similarity of physical properties of the mass\u2013spring system and its graph model. More explanation in this regard can be found in Reference [11]. Forming the graph model for a vibrating system has many advantageous in recognizing the symmetry properties of a symmetrical system, especially in systems consisting of complex symmetries (see Section 5). The graph model of the first example is shown in Figure 5(b). If the mechanical system related to Equation (14) is involved in a symmetry group (say G), then group representation theory can be used to construct an n \u00d7 n orthogonal matrix T such that K\u0303 \u2261 TtKT and M\u0303 \u2261 TtMT (15) in which K\u0303 and M\u0303 have the same block diagonal forms. This reduces Equation (14) to a number of smaller, decoupled eigenvalue problems. It should be pointed out that the mass matrices in the mass\u2013spring problems are always diagonal, so the main focus here will be on the stiffness matrix",
+ " For this purpose, it is necessary to distinguish some of the symmetry operators of the system such as principal axis and reflection planes. The system of our example has only one non-trivial symmetry operation: y , which is a vertical plane. Therefore, the symmetry group of the system will be classified as C1v . Once the point group of system is identified, it is possible to find all of the symmetry operations of the structure; i.e. C1v \u21d2 {e, y} for this case. Let u denote the displacement vector of the system. As shown in Figure 5, the basis for space R2 of the problem will be u= (u1, u2)t. For discrete systems having translational DOFs only, it is possible to construct the i implicitly as follows. If u is an arbitrary displacement field, then each i is defined such that its action on the vector field ( iu) \u2018mimics\u2019 one of the symmetry operations in group G. Thus, iu will be obtained by affecting each symmetry operation of group G on the basis of V (selected before), and ( i ) will show the number of displacement alignments (ui ) that remain unaltered under this transformation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003985_tro.2006.878956-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003985_tro.2006.878956-Figure7-1.png",
+ "caption": "Fig. 7. Vertex\u2013Edge case. Projection on the plane (dotted lines) of the contact manifold for two values of (left); an example of shortest path to a line (right).",
+ "texts": [
+ ", the minimization in (14) is performed over the set (which can also be empty) of RS paths landing inside the edge. All the remarks stated for (8) hold also in this case. 1) Handling Type-B Paths: Let y = mjx + nj be the equation of the target edge vj ; by using (9), the contact manifold between qi and vj is defined by Cij V E( ) = f jqi 2 vjg, and is represented as ijV E( ) = y mjx nj limj cos( + i) + li sin( + i) = 0 which represents a 2-D surface whose projection on the plane xy for a given is a line parallel to vj [Fig. 7 (left)]. Lemma 2: If a Type-B path is optimal for problem (ii), then: 1) the line D0 is perpendicular to the line vj ; 2) the contact point lies at the intersection of D0 and vj . Proof: The constraint f 2 Cij V E , expressed as ijV E( f) = 0, yields f = MT , where M = @ ijV E( f)=@ f is given by M = ( mj 1 limj sin( (tf ) + i) + li cos( (tf) + i)): Thus, we get the system 1 = mj 2 = 3(tf) = (limj sin ( (tf) + i) + li cos ( (tf) + i)) from which we get the following relations: 2 1 = 1 mj (15) 3(tf) = 1li sin ( (tf) + i) + 2li cos ( (tf) + i) : (16) Point 1 of Lemma 2 is proved by (15); by using (4), (9), and (16), we can compute the constant 3(t0) = 1qi (tf) + 2qi (tf) that yields 3(t) = 1(y(t) qi (tf))) 2(x(t) qi (tf)), which implies that the point qi at the end of the path must lie on the line D0. Thus, combined with the contact condition between qi(tf) and the target line vj , we prove point 2. Putting together the contact manifold constraint on the final state and the two transversality conditions, we get again a square system of equations for each path pk of Type-B. As an example, in Fig. 7 (right), we show the solution for the line of equation y = 0:1x+2 and the pair (li = 0:3; i = =4); the shortest path is of type l a l + =2s + e r + b , with a = 0:099, b = 0:449, e = 0:268, and total length L = a + b+ e + =2 = 2:386. 2) Handling Type-A Paths: Although the conditions derived in Section IV-A.2 are still valid for this case, they are no longer sufficient, since ijV E (Wp (0; b; e)) = 0 (17) is underspecified (one equation and two parameters). The missing information is recovered with the following geometric reasoning (see Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001586_s0141-0229(99)00192-1-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001586_s0141-0229(99)00192-1-Figure2-1.png",
+ "caption": "Fig. 2. Layout of the screen\u2013printed sensors comprising three electrodes.",
+ "texts": [
+ " Polymer printing inks, also known as polymer thick film inks (Ercon, Wareham MA, USA), were applied onto the polyester support (thickness of 350 mm from Pu\u0308tz\u2013Folien, Taunusstein/Wehen, Germany) through printing screens (Farben\u2013Frikell, Berlin, Germany) by using an ATMA 600 HE screen-printing machine (E.S.C., Bad Salzuflen, Germany). Between the four subsequent printing steps, the struc- tures had to be heated at 80\u00b0C for about 10 min to dry off residual solvents and cure the patterned pastes. The sensor layout is shown in Fig. 2. Each transducer comprised a platinum working electrode with a diameter of 2 mm, a graphite auxiliary electrode sized 4 3 2 mm and an Ag/ AgCl pseudo reference electrode of the same size. The overall dimensions of each transducer was 20 3 52 mm. Sixty sensors were printed on one substrate sheet at the same time and separated afterwards. Before use the transducers were tempered again for 5 h at 130\u00b0C for additional curing. The ink pigment of the pseudo reference electrode is basically silver containing a small amount of silver chloride"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.7-1.png",
+ "caption": "Figure 2.7. Consecutive finite rotations are not commutative, so they cannot be compounded by vector addition.",
+ "texts": [
+ " This means that the displacement of a rigid body due to successive finite rotations generally will depend upon the order in which the rotations are performed. On the other hand, consecutive infinitesimal rotations obey the commutative law of vector addition; hence, 96 Chapter 2 these are independent of the order of their execution. To visualize this fun damental difference in the properties of finite and infinitesimal rotations, let us begin by considering consecutive finite rotations of a rectangular plate with an edge OP on the x 2 axis and initially oriented in the vertical plane of a spatial frame 1/>, as shown in the diagrams of Fig. 2.7. If the plate shown in Fig. 2.7a is rotated first through a right angle about the x 1 axis and then through a right angle about the x 3 axis, while the same plate shown in Fig. 2.7b suffers the same rotations but in reverse order, we see at once that the final position of 0 P, indeed the orientation of the plate, is not the same. This confirms that the composition of successive finite rotations of a rigid body about concurrent axes is not commutative. The composition of finite rigid body rotations and other related theorems will be studied in the next chapter. Hereafter, we shall focus on the composition of infinitesimal rotations only. In the derivation of (2.19), we have naturally and correctly represented the infinitesimal rotation by a vector symbol L19 =A(} a, without regard for the noncommutative nature of finite rotations",
+ " Therefore, the screw axis passes through the center of rotation 0* whose position vector B* from the origin in ([> is given by We thus find that the given displacement may be reduced to a unique screw displacement consisting of a rotation of 15\u00b0 about an axis a= K through the point at B* together with a pure translation of the body through advance a distance of 2np = 96 em along the axis. (See Problems 3.41 and 3.42.) It was shown in Section 2.7 that successive finite rotations of a rigid body about concurrent axes are neither additive nor commutative. Therefore, as illustrated in Fig. 2.7, the displacement of a rigid body generally will depend upon the order in which the rotations are performed. We saw in a few earlier examples that when the successive rotations are easy to visualize, their com position may be readily written down by use of the direction cosines between the body imbedded axes in their terminal state and those of the spatial set with which they were coincident initially. Needless to say, it is not always easy to perceive the successive and the resultant effects of several complex rotations, so it will be useful to derive the rule for their composition"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002488_s0925-4005(03)00597-5-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002488_s0925-4005(03)00597-5-Figure2-1.png",
+ "caption": "Fig. 2. Schematic diagram of the frame on which the membranes are stretched inside the cuvette.",
+ "texts": [
+ "0159 g of the synthesized reagent in warm distilled water and diluted to 100 ml in a 100 ml standard flask. A Spectronic 20 (Genesys) UV-visible spectrophotometer was used to measure the absorbance of fix wavelength. UV-visible spectra were measured with a Jasco, Model V-570, double beam spectrophotometer. A Perkin-Elmer atomic absorption spectrometer (Model 2380) was used for determination of Ni(II) in hydrogenated vegetable oil. A homemade cell holder [12] was used with a special frame with a size of 8.5 mm \u00d7 35 mm, as shown in Fig. 2. The triacetyl cellulose film was hydrolyzed in order to de-esterify the acetyl groups and to increase the porosity of the membrane by treating the membrane in 0.10 M KOH solution for 24 h and then, the film was washed with distilled water. It was found that further activation processes [13] were not necessary. The cellulose membranes were immediately treated with a 1.0 \u00d7 10\u22123 M ACDA at 30 \u25e6C and in phthalate buffer (pH = 2.2) for 5 h. Then the membranes were washed with distilled water until there was no absorption at the wavelength of the ligand during rising",
+ " Then the sample was heated to 700 \u25e6C for 1.5 h in an electrical furnace. The remained ash was dissolved in 10 ml concentrated HNO3. The solution heated to dryness. Three consecutive additions of 10 ml distilled water were then made and each time the solution evaporated almost to dryness to eliminate excess acid. The residue was dissolved in 50 ml of water and filtered with filter paper (Whatman No. 1). The filtrate solution was used for analysis. The measurements were made on the membrane, which was stretched on a special frame (Fig. 2); with the size of opening of 8.5 mm \u00d7 35 mm. The control sample against which the measurement was performed consisted as cellulose film treated in the same way but without ACDA for study immobilization of ACDA on the film; whereas a cellulose film treated in the same way but without Ni(II) for nickel determination. The control sample was also stretched in the same way inside the cuvettes using a frame of the same size. Kastov and Tzankov [13] showed that only reagent with amino groups could be linked chemically with triacetyl cellulose"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000705_a:1007974811131-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000705_a:1007974811131-Figure1-1.png",
+ "caption": "Figure 1. MANUTEC r3 robot: (a) view; (b) kinematic scheme.",
+ "texts": [
+ " After linearizing Equation (85) in the vicinity of x = 0, it follows [16, 17, 40] that: x\u03072 = A(t)x2 +B(t)x1 + \u03b1(x2, x1, t) + \u03b2(x2, x1, t)\u00b5, (86) where A(t) and B(t) are 2m\u00d7 2m and 2m\u00d7 2(n\u2212m) matrices, respectively and \u03b1(x2, x1, t) = o(\u2016x\u2016) when (x) \u2192 0 and suptA(t) < \u221e since q0(t), q\u03070(t) belong to bounded regions. The sufficient conditions for the asymptotic stability of the system of differential Equations (85) are given by the same theorem [16, 17, 40] mentioned in Section 4. So the control laws (78)\u2013(80) ensure a desired quality of stabilization of the robot interaction force F0(t). At the same time, the stabilization of the robot motion q0(t) can also be achieved. In order to illustrate our new contact control concept, a simulation case study with a MANUTEC r3 [42] industrial robot (see Figure 1) has been performed [43, 44]. The parameter data for the industrial manipulation robot MANUTEC r3 [42] were taken from the catalogue. The parameters of deburring tool and process were used as in the real-system experiment [44] (see Figure 2). The process parameters and the parameters of the tool used in the simulation phase are given in Table I. A general model of impedance was adopted for the environment model, so that the dynamic environment (i.e., the worksurface) resisted the tool motion x(t) in all coordinate directions, including the tool rotation resistances"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000397_s0013-4686(98)00307-7-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000397_s0013-4686(98)00307-7-Figure2-1.png",
+ "caption": "Fig. 2. Cyclic voltammograms of (a) N,N 0-diphenyl-1,4-phenylenediamine and (b) [4-(phenylamino)phenyl]-1,4-phenylenediamine in TBABF4/diphenyl phosphate/acetonitrile solution at a scan rate of 50 mV/s.",
+ "texts": [
+ " Similarly to UV-vis-nir absorption studies, in situ Raman spectroelectrochemical studies were correlated with cyclic voltammetry and performed in the same electrolyte, using the same working, counter and reference electrodes used during the voltammetric measurements. In order to avoid degradation, the laser beam power was limited at 200 mW. By studying the oxidation and reduction of these two phenyl-end-capped oligoanilines in an acidic solution, the range of creation of the radical species can be established. The cyclic voltammograms of phenylend-capped dimer and tetramer in acetonitrile solution at a scan rate of 50 mV/s are shown in Fig. 2. Each voltammetric curve displays two well-de\u00aened reversible waves [8\u00b110]. Scanning in the anodic direction, the dimer shows two one-electron transfers at Epa1=300 mV and Epa2=600 mV vs Ag/Ag+ . The tetramer shows two two-electron transfers at Epa3=250 mV and Epa4=700 mV vs Ag/Ag+ . The model compounds of emeraldine salt, the phenyl-endcapped dimer radical cation and the phenyl-endcapped tetramer radical dication are generated at the potential of the \u00aerst anodic wave. The good reversibility, even after several hundred cycles, conjugated to the invariance of the ratio of the anodic/cathodic peak currents (ipa/ipc=1"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003049_b:tril.0000044509.82345.16-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003049_b:tril.0000044509.82345.16-Figure12-1.png",
+ "caption": "Figure 12. Three-dimensional plot of mean shear stress versus pressure and temperature based on computed Hertz pressure and calculated average film temperature at each location (only data at \u2021 1.0 GPa).",
+ "texts": [
+ " Figure 11 shows three computed friction-coefficient maps based in the contact centre being in three different locations, at i \u00bc 10.8, 12.8 and 14.8 grid spacings respectively from the left-hand edge of the region mapped. (The friction coefficient outside of the Hertz contact region has been set to zero). Based on these maps, the contact centre was taken to be at the i \u00bc 12.8, j \u00bc 16.5 grid position in this case. Using this approach, the temperature and pressure at each grid point and each slide-roll ratio studied were determined. Figure 12 shows a 3-D surface plot of calculated shear stress versus film temperature (from equation 8) and computed pressure (from equation 9) obtained by combining results from all of the different slide-roll ratio tests carried out in this study. To obtain this plot, the pressure and film temperature range over which measurements were made was divided into a series of equally sized rectangular domains and all of the measured shear-stress values lying within each of these domains were averaged. This gave a matrix of mean shear-stress values at 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003285_0020718508961120-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003285_0020718508961120-Figure2-1.png",
+ "caption": "Figure 2. Example 1.",
+ "texts": [
+ " Ifn=O, thefunctionf(~)ismonotonicfor all t 2 t o ; if n is a finite integer N, I ,= [ th, co) and the function is monotonic for all t 2 t',. For n infinite, Q = l f , I:=(t i , tf) and Figure 1. Properties ofL(t). The difficulties encountered earlier in ordering functions in 9VIo,, , are not entirely avoided by confining our attention to the class A. As shown in the following example, if f , ( . ) , f 2 ( . ) E A, the ratio f,&, while well-defined for all t 2 to, t o E R+, may grow in an unbounded fashion along one sequence, tend to a constant along a second sequence and tend to zero along a third sequence. Example 1. (Fig. 2) Let ( t i ) , { t i ) and ( T ) be three unbounded sequences in R + such that t i c ti < t i + ,, T,=T, =0, T Z i + , =( t j+ , - t i ) + T Z i - , and T , i = ( t i - t j ) + T 2 i - 2 , where i~ { I , 2, ...I. D ow nl oa de d by [ T he U ni ve rs ity o f M an ch es te r L ib ra ry ] at 1 1: 10 1 0 O ct ob er 2 01 4 Stability analysis of adaptive systems Let f , ( . ) and f , ( - ) be two functions defined as Choosing the sequences { t i } and {ti} in such a manner that T + 1 lim -=a i - m we see that ( f l ( t ) / f2 ( t ) l tends to zero on the sequence { t i ) , to infinity on the sequence { t i ) and to unity on a sequence { t i ' ) where ti < t;',- c t i , t i c t';i < t i + t'; = t ; "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure16-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure16-1.png",
+ "caption": "Fig. 16 Boundary and displacement conditions for the press-\u00aet simulation",
+ "texts": [
+ " All the analyses for the press-\u00aet curve determination have therefore been carried out under the linear elastic hypothesis. Three different wheelsets have been examined, named Sao Paolo, United Kingdom and Fiat Ferroviaria, shown in Fig. 15. For each wheelset, a range of possible interferences has been considered, due to the machining tolerance of the axle and wheel. The press-\u00aet operation was simulated constraining one end of the axle in its longitudinal direction and applying a displacement at the wheel, as shown in Fig. 16. The sum of the reaction loads at the constrained end represents the press-\u00aet load, whose value is expected to increase with the wheel displacement, due to the increasing friction-resistant load. Proc. Instn Mech. Engrs Vol. 218 Part F: J. Rail and Rapid Transit F01203 # IMechE 2004 at HOWARD UNIV UNDERGRAD LIBRARY on February 28, 2015pif.sagepub.comDownlo ded from Several calculations were carried out in order to study the effect of the parameters under investigation. The local effects of the oil injection groove and that of the wheel seat chamfer are visible in Fig",
+ " The friction resistant load was then calculated independently from the integral of the friction tangential stresses, which, using Coulomb\u2019s law, was found to be proportional to the local contact pressure. The press load is \u00aenally given by the sum of the friction-resistant loads acting on each of the \u00aeve jth zones: P \u02c6 X j \u2026Lj 0 f \u2026 p\u2026z\u2020\u2020 p\u2026z\u2020 2pR dz \u20267\u2020 where f\u2026 p\u2020 is given by equation (4). To obtain the press-\u00aet curve, equation (7) is calculated for a variable contact length. This is made by considering the contact pressure, given by equation (5), to act only on the wheel length x (see Fig. 16) in contact with the axle. F01203 # IMechE 2004 Proc. Instn Mech. Engrs Vol. 218 Part F: J. Rail and Rapid Transit at HOWARD UNIV UNDERGRAD LIBRARY o February 28, 2015pif.sagepub.comDownloaded from Agreement between the press-\u00aet curves obtained by the FEM and those obtained by the simpli\u00aeed approach were very satisfactory for the wheelsets under investigation, as shown by the example reported in Fig. 22, where a good prediction of the experimental results can also be noted. Obviously, the simpli\u00aeed approach does not take into account the effects of the oil injection groove and that of the wheel seat chamfer, but they have been proved to modify the pressure distribution only locally, without any great in\u00afuence on the press-\u00aet curve and on the maximum press load in particular"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003688_tcst.2004.833622-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003688_tcst.2004.833622-Figure3-1.png",
+ "caption": "Fig. 3. Relative relation diagram in body coordinate.",
+ "texts": [
+ " Finally, to show that Theorem 1 is satisfied, we need to show that before entering ZEM phase, which has been proved in [1]. Therefore, the target-tracking objective during the flight before entering ZEM phase can be completed as derived by the aforementioned proof of theorem 1, but after the ZEM phase, the principal goal of bounded target interception as claimed by the aforementioned theorem can be achieved. Accordingly, the desired overall acceleration perpendicular to the LOS can be derived due to the result in Section III, which together with in the direction leads to the desired acceleration (see Fig. 3) of the missile, namely Hence, the resulting acceleration of the missile due to TVC and DCS together will lie on the plane . We note the following two facts: 1) projection of the desired resulting acceleration onto the axis of is simply and 2) projection of onto the axis perpendicular to the plane will be identically zero. Then, we can derive the following constraint equations of in the body coordinate frame as: By Cramer\u2019s rule, the acceleration [see Fig. 1(b)] generated by the divert control system, denoted as , can be derived as Remark 1: To avoid the singularity for computing the , we propose one possible solution to modify the force from the divert control system when the singularity condition \u201c \u201d occurs as follows: and if and if To validate the proposed sliding-mode guidance and autopilot of the missile system, we provide a realistic computer simulation in this section"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000540_0094-114x(95)00106-9-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000540_0094-114x(95)00106-9-Figure2-1.png",
+ "caption": "Fig. 2. Assembly of second platform point.",
+ "texts": [
+ " T H E O R Y OF T H E P R E D I C T O R A L G O R I T H M The base and the platform reference frames are chosen with their X and Y axes in the corresponding planes, such that b~ = [bix biy 01T (l) p~ =[p~ p~y 0] T (2) p~ = ~ + ~. (3) Selecting the first two direction cosines dlx and dly of the first leg vector (i = 1), we get the third direction cosine as As the solution for the negative value is just the mirror image of the solution with the positive value, we consider only the positive sign for the present. Hence, d,, = x/1 -- dl2x -- d~, (4) The location of the first platform point is then given by ?ix] L., J Now, B2P t =lp~ - b21, B2P2=S2 and PIP2 are all known and they form a rigid triangle [Fig. 2(a)] which ~'an r~tate about the line B2P, constraining the second platform point P2 to move in a circle. In the triangle B2Pj P2, a perpendicular f rom/ '2 on B2PI is drawn [Fig. 2(b)], the foot Ot and the length O1 P2 = r~ is determined from the following relations. B2P~ + B2P~ - P1P~ cos cq = 2B2P1 x B2P 2 sin ~ = 4 1 -- cos 2 cq B20, = B2P2 cos ~1 rl : 01 P2 = B2P2 sin ~1 The position vector of O1 is obtained as follows. A ot = b2 + B20, = ~ + B2OIB:PI (6) Next, we fit a triad .~ at the point O1 to act as a reference for the rotation of AB2PI P2 and hence of the point P2. The Z-axis of .~ is set along O, P~ and the X-axis is taken parallel to the base plane and perpendicular to 01P,, the Y-axis is automatically set by the right hand rule (~ = ~ x ~)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-9-1.png",
+ "caption": "Figure 1-9. Surface plasmon resonance (SPR): resonance dependent on (a) angle of incidence and (b) wavelength of incident radiation.",
+ "texts": [
+ " The resonance condition is monitored by use of a position-sensitive linear photodiode array [294]. This principle is commercialized by Pharmacia. At present it is one of the most commonly used bioanalytical systems for examining affinity reactions. (b) Another possibility is to select out of white light the wavelength which fulfils the resonance condition [85]; by use of a diode-array spectrometer, the dip of attenuated reflection is recorded specrroscopically. Both principles are illustrated in Figure 1-9. 1.2 Principles of Optical Transduction 17 As in the case of intrinsic fiber optics, guided radiation can be used to couple via a buffer layer to a metal film and excite surface plasmons at the opposite interface. Suitable refractive indices for buffer layers and the correct wavelength guided in the waveguide are necessary to find a resonance condition. Such devices (slab waveguide-based SPR) can be used as sensing systems [359]. A schematic representation is shown in Figure 1-10. First attempts have been undertaken to achieve a multi-element surface plasmon resonance chip"
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+ "image_filename": "designv11_6_0002746_0278364905060149-Figure26-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure26-1.png",
+ "caption": "Fig. 26. Measurement device for frame deformation.",
+ "texts": [
+ " In coordinate measuring machines, first a coordinate of the probe tip BPr , which is observed in the moving coordinate system \u2211 B , is calculated by the forward kinematics from the limb\u2019s lengths measured by the linear scale units. Secondly, the measured coordinate BPr is transformed to a coordinate B0Pr represented in the initial coordinate system \u2211 B0 by B0P r = B0P B + B0RB BP r. (7) In brief, all measured coordinates are rewritten in the initial coordinate system. at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from Figure 26 depicts an example of the measurement method for the distance changes, u1 \u2212 u6, shown in Figure 23. The spherical joint is mounted on a joint support made of low thermal expansion cast iron. A Super-Invar rod is used as a spanner between the joint support and the surface plate. One end of the rod is connected to the surface plate by a flexure hinge. The other end is guided via a hole in a holder mounted on the joint support. A displacement sensor installed in the hole measures the displacement change in the rod end\u2019s surface in the longitudinal direction of the rod"
+ ],
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+ "image_filename": "designv11_6_0001042_robot.1994.350911-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001042_robot.1994.350911-Figure7-1.png",
+ "caption": "Figure 7 - A Grasp with Concurrent Forces",
+ "texts": [],
+ "surrounding_texts": [
+ "Figure\nEQUILIBRIUM\n4 - Classification of Planar Equilibrium Grasps\n4.1 Transformation of Stiffness Matrices When modeling multiple contacts, we use a leading subscript to denote the contact. For example, ' K A would be the curvature K A for the finger at the i f h contact and ioc is the fixed frame at the ith contact. Note further that Ax, and Ay, refer to the contact frame, but they can be related to other reference frames through appropriate transformations. We use a fixed frame 0 at an arbitrary point. If we let 'K, be the stiffness matrix from either Equation (1 1) or (17) (whichever is applicable), and (ldB Idy) be the coordinates of 0 as seen from loc, then the change in the wrench referred to the coordinate system at 0 for any infinitesimal rotation or displacement, due to contact i , is given by:\nwhere:\n. .\nAw0= iTT 'K, iT Axo (18)\ncos '@ -sin'@\nand l @ is the angle of rotation of the frame 0 with respect to the contact frame ioc (see Figure 3 for definition of a).\n4.2 Constant External Forces Consider the gravitational force on body B acting through the center of gravity. We define a coordinate system, oCg, fixed in space and coinciding with the center of gravity, where the axes are aligned such that gravity acts in the ycg direction. A rigid body motion of body B will not change the gravitational force, but will result in changes in the moment about the origin of ocg, given by:\n0 0 0 AxXca [ :Ica =[ ;g ; ;Ica[\";,] Or Awcg =% Axcg (19)\nwhere m is the mass of body B and g is the gravitational force. A transformation matrix TCg (analogous to T in (18)) can be employed to express this in the coordinate frame 0.\n4.3 Frictionless Planar Grasps Many of the most common equilibrium grasps are not form closed. To grasp a planar object with form closure\nrequires at least four frictionless point contacts. Whole arm manipulators are capable of establishing only a limited number of contacts with an object. And many, if not most, multifingered hands do not have enough fingers to effect a form closed grip. Here we establish criteria for stability of non-form closed equilibrium grasps (see Figure 4). But first we adopt an equivalent definition of form closure [ 141:\nDefinition: An equilibrium grasp with N unilateral contact wrenches is form closed ifand only $\n1) 3, > 0 such that W ch = 0 (where ch is a\n2) W is full rank vector with elements chi )\n(20)\nNote that condition 1 is a stronger condition than that required for equilibrium since it requires C i > 0 for all i . Non-form closed equilibrium grasps must fail to meet either conditions 1 or 2 above. If an equilibrium grasp is not form closed, we construct a submatrix W* from W as follows. In the case where gexf = 0 in Equation (1), W* consists of the subset of wrenches, wi, of W which satisfy condition 1 in Definition (20). In the case where gext # 0 , W* is formed from the union of the subset of wrenches, wi, which satisfy condition 1 and the subset of wrenches, wi, with a non zero intensity in the equilibrium equation W c = gexf (Eqn 1).\nWe consider two cases. First, let gexf = 0. For non-form closed equilibrium grasps, the wrench submatrix, W*, cannot be full rank. This implies the lines of action of the wrenches in W* either meet at a single point, are parallel to each other, or are collinear. Next, consider the case where gext # 0. In this case, given a non-form closed equilibrium grasps, W* may be full rank. If W* is not full rank, the lines of action of the wrenches in W* either meet at a single point, are parallel to each other, or are collinear. Therefore, all non-form closed equilibrium grasps can be grouped into four categories: 1) Grasps in a external force field (such as gravity) where the Rank(W*) is full.; 2 ) Grasps where all wrenches in W* (including gravity) are concurrent (intersect at a single point), 3) Grasps in which all wrenches in W* (including gravity) are collinear (Rank(W*) = 1); and 4) Grasps in which all wrenches in W* (including gravity) are parallel, but not collinear. The grasp categories can be differentiated by looking at W* (see [5] and Figure 4).\nThe following four theorems establish stability criteria for all of the categories of non-form closed planar grasps, with frictionless point contacts.\nTheorem 1: A planar equilibrium grasp with collinear wrenches (including gravity if non zero) is stable if\n2825\n1-",
+ "Der ~ ' T T i ~ , IT+ T T ~ K ~ ~ T ~ ~ ~ and z-%&iF are both negative, and unstable if either one is positive. I\" i s 1 i=IIKA+'K,\nTheorem 2: A planar equilibrium grasp with N parallel contact wrenches is stable (unstable} if fWi~,, is negative (positive}. i = l KA+'KB\nTheorem 3: Any planar equilibrium grasp, in which all of N contact wrenches (and gravity ifnon zero} are concurrent\nnegative (positive}. Here ir is the signed magnitude of the vector from contact i (the center of gravity of the body, in the case of rcg) to the point where all forces intersect, positive if the vector is in the same direction as the ith normal force, (gravity, in the case of rcg} and negative if it is in the opposite direction.\nTheorem 4 Any planar equilibrium grasp composed of frictionless point contacts in which W* has full rank is stable, except grasps in which one of the contacts in W* is a convex vertex contacting a convex vertex.\nTo prove these theorems, consider the composite stiffness matrix, &,, obtained by summing the contributions\nfrom each 'K, (and IC,-,) after referring it to the coordinate system 0. The system is stable if the eigenvalues of &, are strictly negative and unstable if at least one eigenvalue is positive. Thus stability implies that the determinant of each principle minor of -KO is positive. This leads directly to Theorems 1-4. Details are furnished in [ 5 ] . Theorem 1 can be used to establish a number of special case results:\nLemma 1: A planar equilibrium grasp with two opposed collinear fn'ctionless contacts (in the absence of gravity} is\n2 iKA ' K , ;=I K,+ K R -are both negative, and unstable if either one is\npositive. Here r is the signed magnitude of the vector from contact two to contact one, positive if the vector is in the same direction as the second n o m 1 force, and negative if it is in the opposite direction.\nLemma 2: An equilibrium grasp with a single frictionless contact plus gravity is stable if K A K , and - K A (rKB - 1) are both negative, and unstable if either one is positive. Here r is the signed magnitude of the vector from the center of gravity to the contact, positive if the vector is in the same direction as the gravitational force and negative if it is in the opposite direction.\nLemma 3: Given an equilibrium grasp with two frictionless contacts, all grasps of the form in a} Figure 8a ( ~ K A , lKg, 2 K ~ , 2Kg > 0) are unstable. b} Figure 86 ( I K A , ~ K A >O , KB, 2Kg < 0) are stable. c) Figure 8c ( ~ K A = 2 K ~ = K A < O , ~ K B = 2Kg =Kg>O}\nare stable if r e 2 or r > - 2 , and unstable if K B K.4 - 2 c r < -2 ( r is as dejked in Lemma I} . K B KA\n4.4 Frictionless Grasps of Polygons The above theorems apply to polygons. For contacts on the edges of the grasped polygon, Kg = 0. For contacts on the vertices of the polygon K , -) fm, where K , + +m for a \"convex\" vertex and K, + --oo for a \"concave\" vertex. In these cases each term ( K A , K B , and r) is evaluated as it\napproaches the limiting value (e.g. Lim = K~ 1.\nExample 1: Consider the grasp as shown in Figure 8d. In this case, I K A = 0.5, ' K g = 0, 2 K g = 0, 2 K ~ = 0.5, 3 K ~ = -0.5 cm-', 3Kg = 00, l r = 2r = 5 cm, 3r = -3 cm, and rcg = 4.5 cm. The forces are IF = 10N, 2F = 10N, 3F = 15N, and mg = 4.3N. Applying Theorem 3, we see the grasp is stable\nK , + w K A + K,\nsince 5: ('riKB - l)(iriKA + F, + mgr, = -98.15 < 0. i=l 'K,+'K,",
+ "Lemma 4: A equilibrium grasp with N frictionless point contacts on the edges of a convex polygon (in the absence of gravity) is stable if Rank(F*) = 2, where F* is a 2x.N matrix composed of the force vectors with non zero intensities (the first two rows of W*). See [ 5 ] for aproof.\n4.5 Frictional Grasps If we assume that the frictional forces are bilateral forces and that the frictional constraints are satisfied, all equilibrium grasps are \u201cform closed\u201d and therefore stable. For example, consider a grasp with two frictional contact points (under the assumption that the frictional force is strictly less than the maximum allowable frictional force). When the force displacement relations are added together and the results analyzed, we find that all equilibrium frictional two-contact point grasps are stable. A grasp with only one frictional contact does not have this property, however, and the following lemmas address these cases:\nLemma 5: An equilibrium grasp with one frictional contact opposing a gravitational .force is stable (unstable) if ( K A + K,)r+cos@ is negative (positive). Here r is us defined in Lemma 2, and 0 is the angle of rotation of contact frame 2 with respect to contactframe 1 (see Fig. 3) .\nJ.emma 6; An equilibrium grasp with one frictionless point contact and one .frictional point confucf (without gravity) is\n(positive), where the frictionless contact is contact 2, r is as defined in Lemma 1, and 0 is us defined in Lemma 5.\n5.0 Discussion In this paper, we categorize all planar equilibrium grasps, and establish results which can be used to determine the stability of virtually all planar grasps (including indeterminate grasps) by examining the eigenvalues of the combined stiffness matrix. The exception to this is the case where one of the eigenvalues becomes zero, when Theorems 1, 2, and 3 cannot be used because neither the criteria for stability or instability is satisfied. Note that Trinkle [14] shows a result similar to Theorem 4, but is limited to contact between verticies and suaight edges.\nAlthough most of our results deal with frictionless contacts (which in actuality do not exist), this does not imply our results are meaningless. In fact, the results are extremely useful because they can be used to predict which grasps are stable due to the geometry of the grasp, and thus do not rely on friction for stability. By grasping an object such that the frictionless contact model is stable, underestimating of the coefficient of friction will not potentially result in the object being dropped. Friction can only enhance the stability of the grasp. Also note that the general approach in this paper is easily applied to spatial grasps (see [SI for details).\nIt is interesting to note that the stability of non-form closed grasps with frictionless contacts has much in common with the idea of second order mobility, as proposed by Rimon and Burdick [ l l ] . However, it is incorrect to assume equivalence between second order immobility and stability. In general they are not the same. An exception to this is a two finger grasp without gravity, where the results in [12] are essentially equivalent. It can be speculated that the special case of a second order mobility analysis of a statically determinate frictionless grasps, without gravity, may give the same result as our stability analysis.\nFinally, we close by pointing out that in most grasping situations, stability is a much more important criteria than form closure, even though form closure has received far greater attention. Indeed, often the only reason a researcher tries to obtain a form closed grasp is that it is stable.\nAcknowledgement This work was supported by NSF Grants MSS9157156 and BCS 92-16691. ARPA Grant N0014-88-K-0632 and NATO grant No. 0224/85.\nReferences [ l ] M. Cutkosky and I. Kao, \u201cComputing and Controlling the\nCompliance of a Robotic Hand,\u201d IEEE Trans. on Robotics and Automuion, Vol. 5 , No. 2, pp. 151-165, April 1992. [2] M. Cutkosky and P. Wright, \u201cFriction, Stability and the Design of Robotic Fingers,\u201d Int. J . of Robotics Research, Vol. 5 , No. 4, pp. 20-37. Winter, 1986. [3] H. Hanafusa and H. Asada. \u201dStable Prehension by a Robot Hand with Elastic Fingers.\u201d Robor Morion Planning and Control, ed. M. Brady. Cambridge: MIT Press, 1982. (41 W. Howard and V. Kumar. \u201cA Minimum Principle for the Dynamic Analysis of Systems with Frictional Contacts,\u201d IEEE Cor$ on Robotics and Automuion, pp. 437-442, 1993. [SI W. Howard and V. Kumar, \u201cOn the Stability of Grasped Objects,\u201d Submitted to IEEE Transactions on Robotics and Automarion, Feb. 1994 [6] M. Mason and 1. Salisbury, Robot Hands und the Mechanics of Manipulation Cambridge, MA: MIT Press, 1985. [7] B. Mishra and N . Silver, \u201cSome Discussion of Static Gripping and Its Stability,\u201d IEEE Transacrions on Systems, Man, and Cybernetics, Vol. 19, No. 4, pp. 783-796, July/August 1989 [8] D. Montana, \u201cThe lnematics of Contact and Grasp,\u201d Int. J. of Robotics Research, Vol. 7, No. 3, pp. 17-32, June, 1988. [9] D. Montana, \u201cThe Conditions for Contact Grasp Stability.\u201d IEEE ConJ on Robotics und Automation. pp. 412-417, 1991. [ I O ] V. Nguyen, \u201dConstructing Stable Grasps,\u201d Int. J . of Robofics Research, Vol. 8, No. I , pp. 26-37, February, 1989. [ 111 E. Rimon and J. Burdick, \u201cTowards Planning with Force Constraints: On the Mobility of Bodies in Contact,\u201d IEEE Con5 on Robotics and Automation, pp. 994-1000, 1993. [ 121 E. Rimon and J . Burdick, \u201cA Configuration Space Analysis of Bodies in Contact - Part 2: 2nd Order Analysis,\u201d Submitted to Mechanism and Machine Theory, 1993. [13] N. Sarkar, \u201cControl of Mechanical Systems with Rolling Contacts: Application to Robotics,\u201d Ph.D. Thesis, University of Pennsylvania, 1993. [ 141 1. Trinkle. \u201cOn the Stability and Instantaneous Velocity of Grasped Frictionless Objects.\u201c IEEE Transacfions on Robotics andAutomaiion. Vol. 8. No. 5 , pp. 560-571, October, 1992. [ 151 J . Trinkle, A. Farahat. and P. Stiller. \u201cFirst-Order Stability Cells of Frictionless Rigid Body Systems,\u201d Conditionally accepted by IEEE Trans on Robotics & Automation, Oct. 1993."
+ ]
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+ "original_path": "designv11-6/openalex_figure/designv11_6_0000885_s0263-8223(00)00103-3-Figure2-1.png",
+ "caption": "Fig. 2. Production of the composite beam.",
+ "texts": [
+ " Production of the composite beam The composite beam consists of high-density polyethylene as a thermoplastic matrix and steel \u00aebers. Polyethylene is placed into the moulds and they are heated to 190\u00b0C by using electrical heater. Subsequently, the material is held for 5 min under 2,5 MPa at this temperature. The temperature is decreased to 30\u00b0C under 15 MPa pressure in 3 min, and a polyethylene layer is manufactured. The steel \u00aebers are placed between two thermoplastic layers and processed in the same way described above, as shown in Fig. 2. Thus a composite layer is obtained. The thickness of the composite layer is 4 mm. The composite beam is manufactured from two composite layers by using the same way described above. The mechanical properties and the yield strengths of the beam are measured by using strain gages and the Instron tensile machine, as given at Table 1. The yield strengths of the beam in the second and third principal material directions are the same due to the same alignment of the \u00aebers in these directions. As a result, Y Z and p X 2 1 X 2 1 Y 2 \u00ff 1 Z2 \u00ff is equal to 1"
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+ "original_path": "designv11-6/openalex_figure/designv11_6_0001835_s0301-679x(02)00024-5-Figure2-1.png",
+ "caption": "Fig. 2. Point loading of elastic half-space.",
+ "texts": [
+ " The load-carrying capacity is given by W\u0304 pr\u03042 pp\u0304p 2p 0 1 r\u0304p p\u0304r\u0304dr\u0304dq (5) If an eccentric load acts on the x-axis of the bearing surface only, the moment load-carrying capacity is given by M\u0304 M\u0304y 2p 0 1 r\u0304p p\u0304r\u03042cosqdr\u0304dq (6) The loading point RL is expressed by R\u0304L M\u0304 / F\u0304 (7) where F\u0304 W\u0304 is given for the static characteristics of the bearing. The frictional torque is written as T\u0304 1 2p 2p 0 1 r\u0304p ( w\u0304 3 r\u03043 h\u0304 h\u0304r\u0304 \u2202p\u0304 \u2202q)dr\u0304dq (8) The total power loss \u2014 the sum of leakage and frictional loss \u2014 is given by L\u0304 L\u0304Q L\u0304T p\u0304sQ\u0304out T\u0304w\u0304 (9) . Fig. 2 shows the elastic model for the pad of an elastic half-space. On the x\u2013y plane, the elastic deformation \u03b4e at point B, due to the effect of pressure applied at point A, is written as de (1 n2) pE pr1dr1dq L (10) where L (r2 r2 1 2rr1cosq)1/2 is defined. If the pressure acting on point A is assumed to distribute uniformly around the band-land of the radius r1, the elastic deformation at point B is expressed by [14,15] he (1 n2) pE pr1dr1dq( 1 L1 1 L2 % 1 Ln ) (11) Then, from Eqs. (10) and (11), the elastic deformation \u03b4e at point B, based on the effect of pressure applied at point A, is rewritten as de 1 /L (1 /L1 1 /L2 % 1 /Ln) he (12) where he is given in Eq"
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+ "caption": "FIGURE I . Fragment-simulating projectile, 0.22 calibcr. steel.",
+ "texts": [],
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+ "mode of penetration of nylon ballistic panels by fragment-simulating projectiles is a cutting, shearing mechanism: Shear forces required for yarn failure are usually less than tensile forces. Penetration is always at a slight angle, with the 90\" edge of the FSP leading. Many yarn ends terminated in a smooth surface (in a tensile break the filaments break at random places along the yarn). Penetration of the cloth in certain expenmental situations occur in a manner precluding tensile failure. The force required for nylon or Kevlar yam failure is less for a rectangular leading surface than it is for a chisel-shaped leading surface.\nThe tensile work done in breaking nylon filament is known to be velocity dependent [3,4,6]. In Part I of this investigation [ 5 ] , we reported that the work of penetration per interior layer does not vary significantly with the velocity of the fragment-simulating projectile (FSP), provided the mechanism of penetration remains the same. This difference in behavior is the subject of this report. (Part I includes a section on terminology,)\nThe FSP penetrates the nylon ballistic panels by a combination oftensile and shear modes. It may be that the tensile mode is not involved at all. The fact that there is cone formation, the cross patterns at the holes at all layers, and the overlapping of the ends of the (same) yams at the holes refutes this possibility.\nCosgren el al. [ I ] found that the work of tensile failure of nylon 66 filament is velocity dependent from quasi-static conditions UP to about 210 m/s. The ballistic velocities in this study vary from about zero (exiting velocity for VSO determinations) to lo00 m/s. Also we have shown in Part I that penetration proceeds through the intenor layers in two stages, the first of which involves shallow cone formation. Obviously from the trigonometry of the situation, the yams involved in the cone are being extended at a much lower velocity than the speed of the projectile. Thus, there is a definite overlap and no apparent reason why the work of tensile failure should not also be velocity dependent at the higher velocities. If most of the work of yam failure were tensile work, then ballistic penetration\nshould be strongly velocity dependent, and a11 of the plots of Vs? versus layers, as shown in Part I, should be nonlinear. Since this is not the case, we conclude that the work of penetration is weakly (within experimental error) velocity dependent.\nWe have now reconciled one problem but created another. What then is the major mode of penetration? What remains is a cutting, shearing mechanism.\nIs shear failure of the yarns velocity dependent? There is a basic difference between tensile and shear failure. Tensile failure depends on the propaption Of the strain wave to the yam breaking point (a minimum), both of which are velocity dependent. Under shear conditions, the yarn fails at the place where the shear is applied regardless of the velocity of the missile. Consequently, an average value of the shear strength is always involved. We believe that there is a sufficient difference in the manner of failure to accommodate the postulate that shear failure is velocity independent, at least at ballistic velocities.\nEvidence for the Cutting, Shearing Action of FSPs\nThere is considerable evidence to support the hYpothesis that a cutting, shearing action at the 55' and 90' edges, R1 and R2 ofFigure 1, is important in penetration. The missile is certainly going to penetrate the panel in the easiest way possible, that is, the one requiring the lowest force. Table 1 shows some tensile and shear data taken from Finlayson [2].\nAccording to the Dupont handbook On Zflel (nYIon), the tensile strength of nylon is about 12,000 PSI, I This paper reports research sponsored by U.S. Army Natick Research, Development and Engineering Center and h a k n assigned TP-2467b in the series of papen approved for publication.\n0040-5 175/88/58m3-161$2.00 Q Textile Research'Institute\nat Elsevier Scirus on June 5, 2015trj.sagepub.comDownloaded from",
+ "I62 TEXTILE RESEARCH JOURNAL\nTAME 1. Shear and tensile tcnacities for several yams.\nShear tenacity. Tensile tenacity, &denier ddenier\nFortisan ti 1 .17 8.00 Nylon I .27 4.45 Linen 0.92 2.93 Vinyon 1.10 3.08 Viscose 0.12 I .98 Cuprammonium 0.715 2.00 Silk 1.31 3.50 Cotton 0.96 2.63 Celanese 0.65 I .32\nwhereas the shear strength is about 9,600 PSI [7]. Obviously, where both shear (over edge R2) and tensile conditions (over edge R I ) exist and the forces are the same (which appears to be true for this study), the materials in Table I will fail by shear first. FIGURE 3. This second layer shows more clearly that the initial\npenetration is at the 90\" leading edge of the FSP. For isotropic materials in the elastic range,\nI.:=2G(ItNU) ,\nwhere E is the tensile modulus, G is the shear modulus, and NU is Poisson's ratio. Even under theoretical conditions, the tensile modulus is twice the shear modulus. Drawing a polymer yarn generally increases both tensile and shear strength, but increases the former much more (21.\nPhotographs of a 0.22 caliber FSP, which was fired at 0\" obliquity and caught inside a nylon panel, are given in Figures 2, 3, 4, and 5 . All of these figures are from a I2 layer, standard weight, ballistic nylon panel. The photographs show the various stages of penetration of an FSP through a layer of a nylon ballistic panel. These were obtained by removing intact layers of cloth until the leading surface of the missile first appeared, A picture was taken, a layer of cloth was removed, a picture was taken, etc. As Figure 2 shows, the 90\"\nFIGk,RE 4. The { h i d layer again shows that yams crossing the 90\" leading edge of the FSP fail first.\nat Elsevier Scirus on June 5, 2015trj.sagepub.comDownloaded from",
+ "MARCH 1988 I63\n(sharper) edge, R2, appears first, and the projectile a p pears to be at a slight angle (about 15\") to its line of flight. Figure 5 shows that the last yams to yield are those crossing the 55' edges, R 1. These statements have been true for all the arrested FSPs in nylon panels we have examined. In a plot of slope B2 versus obliquity, there is a minimum in the curves for the FSPs at about I5O, which agrees with the observation above.\nFor a projectile with smooth, well-rounded surfaces, there is no doubt that penetration is primarily if not entirely by tensile failure. For FSPs, however, there are several disquieting observations about the ballistic panels, which make penetration solely via tensile strain a rather untenable premise: (a) Figure 6 shows a picture of the cross pattern at a hole in an interior layer of a ballistic panel. Obviously the cross pattern, representing the degree of strain around a hole, is of unequal radius. This indicates that for some inexplicable reason, all the yarns in one direction failed sooner than the cross yarns under the same stress. In some cases there is no strain evidence that the yams that failed were subjected to any tension at all. (b) During a microscopic examination of the holes, we found that many yam ends had smooth surfaces-hardly tensile breaks. (c) For the intenor layers, which are penetrated over a considerable range of velocities, the yarns apparently fail aRer an extension of about 3 mm. Yet many of the yarns that failed in the final layer ( 1) showed much greater extensions. It does not appear reasonable to assign this increase solely to a velocity change in view of the behavior of the interior layers over a range of velocities. Consequently, it appears that the yams that failed in the interior layers were capable of further extension and had not necessarily reached their ultimate strength.\nDuring some preliminary ballistic studies, 1 -inch squares of nylon cloth were interspersed between the layers of cloth of a ballistic panel to see if the squares would act as a drag on the FSPs and, on a weight basis, disproportionately increase the Vs0. Figure 7 shows a picture of a hole in one of these squares aRer firing the 0.22 caliber FSPs at 0\" obliquity. The hole is about 3 mm from the edge of the square. The yarns bordering the hole show no evidence that they have been subjected to tension during penetration. Examination of\nat Elsevier Scirus on June 5, 2015trj.sagepub.comDownloaded from"
+ ]
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+ "image_filename": "designv11_6_0001078_s0167-6911(02)00185-8-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001078_s0167-6911(02)00185-8-Figure1-1.png",
+ "caption": "Fig. 1. Transversal trajectory of a hybrid system with di;erential inclusions.",
+ "texts": [
+ " Hence, we obtain the estimate \u2016\u2019j(3) \u2212 \u2019(30)\u2016ac6 5(eKT + e2KT + 1)6 35e2KT ; \u2200j\u2208N: (6) Assumption 4. The automaton H satis4es the following: (a) The inclusion x\u0307\u2208Fl(x) at each location l satis4es Assumption 3. (b) For each e\u2208E; ge is either a closed; n-dimensional topological manifold with boundary; or an embedded (n\u2212 1)-dimensional C1 submanifold. (c) re is a lower semicontinuous reset map from Rn to the closed; convex subsets of Rn. Remark 5. Assumption 4(c) makes possible the use of Michael\u2019s selection theorem [1]. The following de4nition is essential for our main result. See Fig. 1. De#nition 6. Let e=(l; ; l\u2032) and x(t); be a solution of x\u0307\u2208Fl(x) de4ned for t \u2208 [t0; t1]; with t0 \u00a1t1 and such that x(t1)\u2208 ge. We say that x(\u00b7) is transversal to ge at x(t1) if it ful4lls the following requirements: (1) If ge is an (n \u2212 1)-dimensional submanifold we require that the solution x(t) of x\u0307\u2208Fl(x) can be suitably extended on some interval (t1; s1]; s1 \u00bft1 in a manner that for some open neighborhood V of x(t1) and local coordinates u=(u1; : : : ; un) centered at x(t1) and mapping V homeomorphicaly onto some open neighborhood of Rn; and satisfying un(V \u2229 ge) = 0; x\u0307(t) \u00b7 \u2207un(v)\u00bf1; \u2200v\u2208V; a:e: on {t: x(t)\u2208V}: (2) If ge is a topological n-manifold with boundary we require that the solution x(t) of x\u0307\u2208Fl(x) can either be continued on some interval (t1; s1]; s1 \u00bft1 in a manner that x(t)\u2208 ge\u25e6; \u2200t \u2208 (t1; s1]; (7a) or there exists s0 \u2208 [t0; t1) such that x(t)\u2208 ge\u25e6; \u2200t \u2208 [s0; t1): (7b) Note that if x(t1) is an interior point of ge then (7b) is trivially satis4ed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002607_icsmc.1989.71346-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002607_icsmc.1989.71346-Figure1-1.png",
+ "caption": "Figure 1 - Hardware Layout",
+ "texts": [
+ " -A six degree of freedom, force/torque sensing, sensor ball hand controller built by the German Space Agency DFVLR was used as the input device for the tracking experiments. The DFVLR sensor ball can receive three force, or translational, commands and three torque, or rotational, commands and generate corresponding output. Its internal measuring system generates a new set of output data every four milliseconds independent of the rate of requests for data. Each request for data to the ball is acknowledged immediately to keep the response time as low as possible.[4] Figure 1 shows a drawing of the computer hardware and hand controller layout. I 1 EXPERIMENTAL DESIGN The test subjects tracked the dark gray target ball with a white ball that they controlled with the six dof hand controller. The controlled ball was exactly the same shape and dimensions as the target ball. The target ball would move independently and randomly with a cutoff frequency of .025 Hz., providing a relatively slow target movement. Rotational disturbances were limited to a few degrees, preventing the rotation of the cross hairs from going beyond 45 degrees from the center in either direction",
+ " ' Movement could occur in all six degrees of freedom: xtranslation, y-translation, z-translation, x-rotation, y-rotation, and z-rotation. This movement could occur in one dof during a trial or in any combination of the six dof. The coordinate system used in the experiments consisted of translational movement along the horizontal or x-axis, the vertical or y-axis, and the axis coming out of and into the display or the z-axis. These axes are shown in relation to the display and to the hand controller in figure 1. Rotations about each one of the axes was also possible, with x-rotation simulating a pitch movement, y-rotation simulating yaw, and z-rotation simulating roll. The software recalculated the relative positions of the target and controlled ball at a sampling rate, or frame rate, of 10 Hz. At each sampling instance, a root mean square error (rmse) was calculated for each of the degrees of freedom that were operating. This error reflected the deviation in a particular dof between the psitiordonentation of the target ball (desired position) and the position of the controlled ball"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.27-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.27-1.png",
+ "caption": "Figure 4.27. An epicyclic gear train assembly.",
+ "texts": [
+ " An epicyclic gear train is a system of gears and shafting in which at least one gear moves around the circumference of other fixed or moving gears. The planet gear P 2 shown in Fig. 4.12 rolls around the circumference of gear P 1 , and so the planetary train studied earlier is an epicyclic gear train. An epicyclic arrangement permits an unusual assembly of gears and shafting and it sometimes provides an uncommon angular velocity ratio while maintaining relative simplicity of the design. The motion of the epicyclic gear train shown in Fig. 4.27 will be studied here. The train consists of three bevel gears A, C, and D and two spur gears B and E arranged so that the shaft of B is concentric with the output shaft of gear D. The gear A is fixed in the machine frame 0 = { F; Ik }. The spur gear E is fixed to the input shaft and drives the train through the power gear B which is cut from a special casting that serves as the bearing housing for the epicyclic gear C and as a bearing for the power gear assembly consisting of B and C. The power gear assembly revolves around the concentric supporting output shaft with a specified total angular velocity ro 10 = wi in the machine frame, as indicated in Fig. 4.27. We wish to determine by vector methods (a) the angular velocity of the epicyclic gear C relative to the power gear B, (b) the absolute angular velocity and angular acceleration of C referred to frame I = { B; ik} fixed in B, and (c) the angular speed of the output gear D. The design, as shown in Fig. 4.27, requires that the pitch angles \u00a2 and () satisfy 1/J + 28 = n/2. (4.84) Motion Referred to a Moving Reference Frame and Relative Motion 291 Solution: Part (a). Let frame 3 = { D; nk} be fixed in the output gear D whose absolute angular velocity is denoted by ro30 = .Qn 1 = .QI; and let frame 2 = { C; ek} be fixed in the epicyclic gear C, as shown in Fig. 4.27. Then the angular velocity of the epicyclic frame 2 relative to the power gear frame 1 may be written as ro 21 = w21 e2 = w 21 i2 , and the total angular velocity of C in the machine will be given by (1)20 = 0}21 + (1)10\u00b7 (4.85a) In addition, the three absolute angular speeds of gears B, C, and D are related through the rolling constraint imposed by the gear teeth. Of course, the point Q on gear C is turning relative to the rotating frame 1 in gear B. However, since the reference frames are fixed in the ge:ars, their material points have no motion relative to these frames"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001603_elan.1140071203-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001603_elan.1140071203-Figure1-1.png",
+ "caption": "Fig. 1. Schematic diagram of microdialysis probe: (A) fused silica tube (0.d. 150pm, i.d. 75pm); (B) fused silica tube (0.d. 470pm, i.d. 3 5 0 ~ m ) ; (C) dialysis fiber (0.d. 220pm. i.d. 200pm); (D) stainless steel tube (0.d. 440pm, i.d. 220pm).",
+ "texts": [
+ "0, borate buffer (500 pL) containing acetylcholine esterase (4.6 U) and choline oxidase (0.7U) or choline oxidase (0.7U) and EIe:lectrounaly.~i.s 1995, 7, No. 12 ;i> VtCH Vcrlu~.sgC.FSesC.FSell.sthufi tnhH, 0-69469 Weinlvinz, 1995 1040-0397~YSJI212-I 114 3 5.0Oi.25J0 1115 On-Line Amperometric Assay of Glucose, L-Glutamate and Acetylcholine catalase (3000 U). Each of four enzyme reactors was thoroughly washed with the same buffer used for the immobilization. 2.4. Construction of Microdialysis Probe Microdialysis probes were of a design shown in Figure 1, constructed by inserting a regenerated cellulose dialysis fiber (0.d. 220 pm, i.d. 200 pm; molecular cut-off approximately 50000) into a fused silica tube (0.d. 470 pm, i.d. 350 pm). The fiber was glued in the interior of the fused silica tube, leaving an active length of 3mm, and the fiber tip sealed with epoxy cement. Another two fused silica tubes (0.d. 150 pm, i.d. 75 pm) were also inserted as shown and served as the inlet and outlet. Two fused silica tubes were glued in the interior of the stainless steel tubes (0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.7-1.png",
+ "caption": "Figure 3.7. Sketch of the panel orien tation in cp after a 60\u00b0 rotation about a= -i2 \u2022",
+ "texts": [
+ " It must be born in mind, however, that in the design of the mechanism to move the panel to the terminal state found above, the actual rotation may be done in an infinite variety of ways. There are infinitely many combinations of rotations whose resultant leads to the same rotation matrix (3.130); but there is only one Euler rotation to which all are equivalent. The Euler rotation consists of turning the body through 60\u00b0 about the axis o = -i2 in the conventional right-hand sense. Therefore, the antenna panel has the final orientation sketched in Fig. 3.7. Thus, referring to the figure and recalling (3.123b ), we find the transposed basis transformation matrix [ cos 60\u00b0 0 cos 150\u00b0] [ 1/2 AT= 0 1 0 = 0 1 cos 30\u00b0 0 cos 60\u00b0 ./312 0 0 -./3/2] 0 ' 1/2 which is seen to be the same as R in (3.130). D It is important to realize that there are infinitely many lines through the fixed base point 0 about which the body may be turned so as to move any single given particle P from its initial place to its final position that resulted from a previous arbitrary rotation about 0",
+ "178, before the first paragraph starting with: Another interesting ... , insert the subsubheading \"3.6.1.2. The Basis Transformation Tensor\" p.178, last paragraph, first word; read: \"Finally,\" p.179, equation (3.108b); insert prime to read: \"QT'QT\" p.181, change subsubsection \"3. 6.2.1. Invariant ... \" to subsection \"3.6.3. Invariant Properties of Tensors\"; and note the entry in the Table of Contents, p. xvi. 2 p.184, line 5; read: \"we know that\" p.184, last line; read: \"coincide initially\" p.190, The vector \"i~\" nearest the bottom of the page in Figure 3.7 should read \"i1\" p.203, line 4 below (3.147b); revise sentence to read: \"The resultant axis and angle of rotation generally will depend on the order of rotations in (3.147b ). For two rotations, however, it follows ... \" p.203, In the same paragraph below (3.148), add the sentence: \"Note, however, that tr(R3R2Rl) =tr(R1R3R2) yftr(R1R2R3). p.217, Problem 3.18, equation; read numerator: \"2[T[~ 21 + T[~31 + T[~ 11 ] 1 1 2 \" p.218, Problem 3.23; read: \"-J2/10\" (see revised problem solution p.383 below) p"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002334_bcsj.76.1873-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002334_bcsj.76.1873-Figure8-1.png",
+ "caption": "Fig. 8. LED-based LCW absorbance flow cell. FO: Optical fibers, 1.3 mm in diameter, are used to connect the LED with the LCW cell, and the transmitted light from the LCW to the detector photodiode (PD). The reference light from the bottom of the LED is similarly connected to the reference photodiode (Ref PD); F: interference filter; AF: Teflon AF-2400 tube; J: Stainless steel tube jacket; R: current limiting resistor.39",
+ "texts": [],
+ "surrounding_texts": [
+ "1. Determination of Hydrogen Peroxide in Water. A procedure for determining hydrogen peroxide in water by a batchwise operation was as follows.29 To a 250 mL water sample, 250 mL of perchloric acid (4.8 M) and 250 mL of the Ti\u2013 TPyP reagent were added, and the mixture was allowed to stand for 5 min at room temperature. The solution was diluted with water to 2.5 mL and this served as a test solution. A blank solution was prepared in a similar manner, using distilled water instead of the sample water. The absorbances of the test and the blank solutions were measured at 432 nm (denoted as AS and AB, respectively). The absorbance decrease ( A432) was obtained by, A432 \u00bc AB AS, from which the hydrogen peroxide content was determined. The A432 value was linear against the hydrogen peroxide concentration with the equation: y \u00bc 1:9 105x\u00fe 0:0097 (y and x being the A432 and the molar concentration of hydrogen peroxide, respectively). The correlation coefficient was 0.999 over the range from 1:0 10 8 to 2:8 10 6 M (from 25 pmol to 7.0 nmol per test). Detection limit was 1:0 10 8 M (25 pmol per test). The relative standard deviation (RSD) was 1.2% at 1:0 10 6 M (2.5 nmol per test). The method was readily applied to determine hydrogen peroxide in well water, tap water, ion-exchanged water and water treated by the NANO pureb system (Barnstead), and the results are shown in Table 5. Hydrogen peroxide in ppb levels was determined for ten samples within 1 h.29 Since hydrogen peroxide in the atmosphere is known as one of the pollutants that cause acid rain, a more sensitive, rapid and simpler analysis method of hydrogen peroxide is highly desirable for checking hydrogen peroxide in rainwater. A FIA method using the Ti\u2013TPyP reagent was thus assessed as an effective means to fill this demand.30 As shown in Fig. 5, a flow injection manifold comprises a two-channel system. CS was distilled water that served as a carrier and RS was the Ti\u2013TPyP reagent (30 mM containing 1.6 M HClO4), and both of them were made to flow at the flow rate of 0.4 mLmin 1. The flow lines were made of polytetrafluoroethylene tubing (0.5 mm i.d.). A 100 mL aliquot of water sample was directly injected into the carrier stream through the sample injector. Hydrogen peroxide contained in the water sample was allowed to merge with the reagent stream to form the peroxo complex in the mixing coil (15 m long, 0.5 mm i.d.). The peroxo complex was monitored at 450 nm by a spectrophotometer and its presence was recorded as the peak height of the flow signal. Typical flow signals obtained with the standard hydrogen peroxide are shown in Fig. 6. The response was linear against the hydrogen peroxide concentration ranging from 1 10 8 to 1 10 5 M (1.0 to 1000 pmol per test, r \u00bc 0:999) and the detection limit was 5 10 9 M (0.5 pmol per test, S/N = 2). The results were accurate with the RSD of 0.97% for the injection of 1 10 6 M of hydrogen peroxide (n \u00bc 10). The FIA operation conditions thus permitted 30 samples per hour to be processed. Because the procedure is simple, without any sample pretreatment prior to the injection into the FIA system, the present method enabled rapid analysis of hydrogen peroxide in water. The detection limit obtained by FIA is considerably lower than that obtained by the batch method. In the batch method, the test solution was made by allowing the reaction of hydrogen peroxide with the Ti\u2013TPyP reagent to proceed under highly acidic condition (1.6 M HClO4), followed by diluting the reaction mixture up to 10-fold with water (cf., Ref. 29). Contrary to this, in the FIA method, hydrogen peroxide in the test solution was detected as the peroxo complex under a less di- luted condition compared to the case of the batch method (cf., Ref. 30). In addition, the FIA technique provides precise data with a good reproducibility under a given set of operating conditions. Contribution of these factors, accordingly, leads to the very low detection limit. The hydrogen peroxide content in rainwater collected in the Tokyo area was determined by this method over the range of 7 10 7\u20134:3 10 5 M (Table 6). The recovery tests were made using 1:00 10 6 M hydrogen peroxide with the satisfactory results of 99\u2013102%, indicating the high reliability of the present method.30 2. Measurement of Gaseous Hydrogen Peroxide. Atmospheric hydrogen peroxide plays a critical role in the conversion of SO2 to H2SO4. 4,5 To determine atmospheric hydrogen peroxide whose concentrations are of the level of about 2 ppbv, a highly sensitive analysis method with high specificity for hydrogen peroxide is required. Dasgupta and his colleagues had attained the requisite sensitivity only by fluoro- metric methods with enzymatically mediated reactions in the measurements of gaseous hydrogen peroxide.38 In these methods, special procedures had still been necessary to prevent interference from concurrently present organic peroxides. Recently, Li and Dasgupta have paid attention to our Ti\u2013 TPyP reagent, and consider it as a promising reagent to advance their studies. They succeeded in showing that the Ti\u2013 TPyP reagent was effective to measure ambient levels of gaseous hydrogen peroxide with a light emitting diode (LED)based liquid-core waveguide (LCW) absorbance detector. Because of the absence of interference from organic peroxides, from SO2 and from O3, the detection limit of tens pptv could successfully be attained.39 The collection/analysis system and the LED-based LCW absorbance flow cell fabricated by them are shown in Figs. 7 and 8. The diffusion scrubber (DS) is used for collecting gaseous hydrogen peroxide into the liquid phase. An air pump (AP) draws sample air and H2O2-free air to the DS. The sampling and H2O2-free modes are alternated by switching a threeway valve (V) automatically at the regulated time intervals, and consequently flow injection type signals are obtained. Water and the reagent solution are aspirated with a peristaltic pump (P) and merged in a tee. The stream flows through a reaction coil and then the LCW absorbance cell. The light (450 nm) transmitted through the cell is coupled to the detector photodiode (PD) by the distal fiber optic. Methyl hydroperoxide (MHP) is the most common atmospheric organic peroxide. The commonly used enzymatically mediated peroxide assays cannot differentiate between hydrogen peroxide and MHP, since both behave as peroxidatic oxidants. Since the Ti\u2013TPyP reagent does not work on a redox principle, it showed very different behavior. An injection of MHP into the analytical system showed no response at all, suggesting that the Ti\u2013TPyP reagent should be essentially specific for H2O2 among peroxides.39 (In the course of our studies, we also found that benzoyl peroxide had no influence on the Ti\u2013 TPyP reagent.) Effects of SO2 and O3 will lead to serious errors in the hydrogen peroxide assay. The former will interfere negatively through its fast redox reaction with hydrogen peroxide. The interference from the latter is more complicated: it reacts with bulk water generating hydrogen peroxide, the reaction being promoted by various surfaces and is also catalyzed by OH .40 However, they found that there was practically no interference from concurrently present gaseous SO2 and O3 using a Nafion membrane collector in the DS.38,39 The observed absorbance at 450 nm was linear with gaseous hydrogen peroxide concentration at least up to 5 ppbv. The typical system output is shown in Fig. 9. The detection limit was 26 pptv at S/N = 3. Owing to the work by Li and Dasgupta, the Ti\u2013TPyP reagent was thus shown to be sufficiently sensitive and selective to measure ambient levels of gaseous hydrogen peroxide, and to be adequate for real atmospheric measurements.39 3. Determination of Components and Additives in Foods. Enzymatic methods using commercial kits have become common for determining several components in foods. However, because of high costs of enzymes and difficulties in the continuous measurements, these methods do not appear to be suitable for routine tests. The present FIA method using the Ti\u2013TPyP reagent incorporating with an immobilized enzyme reactor to yield hydrogen peroxide seems promising for developing a new technique in food analysis. Oxalate:35 Oxalate exerts undesirable effects on foodmanufacturing processes. It adversely affects the food taste, and forms insoluble salts with calcium ions present in water to cause turbidity in beer and fruit juices.41 Sometimes it causes a renal calculus in the human body.42 Common methods for determining oxalate in foods include titration by potassium permanganate,43 ion chromatography,44 gas chromatography45 and enzymatic analysis.46 Among them, enzymatic analysis methods are becoming popular. The methods are based on the detection of hydrogen peroxide or NADH produced through the reaction with the respective enzymes. A kit for oxalate assay by measuring the absorbance of NADH produced with dehydrogenase47 has been marketed. However, the NADH method is liable to be affected by reducible substances in food, and the procedure is somewhat complicated. Since the determination of oxalate is thus important in view of food chemistry, application of the present FIA method in combination with the immobilized oxalate oxidase reactor was examined. A schematic diagram of the FIA system is shown in Fig. 10. The carrier solution (CS) was a 0.05 M succinate buffer (pH 3.0). The test solution was prepared according to the procedure of Hansen et al.,47 and injected using a 20 mL sample loop into the carrier stream. By passing through an immobilized oxalate oxidase column (EC), oxalate in the test solution was converted to hydrogen peroxide through the following enzymatic reaction: Oxalate\u00fe O2 ! oxalate oxidase 2CO2 \u00fe H2O2 \u00f01\u00de The resulting hydrogen peroxide reacted with the Ti\u2013TPyP reagent in the mixing coil to form the peroxo complex, which was detected at 450 nm. To prepare the enzyme column, oxalate oxidase (7U) was immobilized on Sepharose in a usual way, and packed in a Teflon tube (3 cm long, 2 mm i.d.). The column could be used continuously for more than 200 runs over a period of 8 h. When the column was stored in a refrigerator at 4 C, no significant decrease in enzyme activity was observed, even after 6 months. Typical flow signals obtained for the standard oxalate solutions are shown in Fig. 11. Response was linear against the oxalate concentration (r \u00bc 0:999), in the range from 5:0 10 7 to 2:5 10 4 M (10\u20135000 pmol per 20 mL injection). The RSD was 0.48% (2:5 10 5 M, n \u00bc 10). The method was applied to the determination of oxalate in different kinds of foods such as vegetables, fruits and beverages. The results are listed in Tables 7 and 8, together with the results obtained by the conventional method using an F-kit currently available on the market, for comparison. The two data sets were in good agreement with each other. Recovery tests using the standard oxalate spiked in each test solution were made and the results were in the range of 97.7\u2013103.0%, indicating the reliability of the analytical data obtained by the present method. The present method was thus shown to be practical and useful for determining oxalate in foods. Sulfite:32 Sulfite is commonly used as an additive in foodmanufacturing and preserving processes due to its antioxidant, antiseptic and antibacterial abilities. However, it has become apparent that sulfite is liable to cause undesirable effects on the human body as an allergic substance,48 and consequently, the allowable amounts of sulfite added in each food product are officially regulated. Among the methods employed so far for determining sulfite in foods,49\u201351 the Rankin method50 is most commonly used; in this method, sulfuric acid formed through the oxidation of sulfite is determined by alkali titration. Although this method allows the detection of sulfite in ppm levels, the procedure involves the use of a particular piece of distillation equipment and is somewhat too complicated to be suited to practical uses. A simpler, more rapid and sensitive determination of sulfite was realized by the present FIA method in combination with an immobilized sulfite oxidase reactor to yield hydrogen peroxide through the following reaction: SO3 2 \u00fe O2 \u00fe H2O ! sulfite oxidase SO4 2 \u00fe H2O2 \u00f02\u00de The FIA system was essentially the same as that shown in Fig. 10. In this case, a Teflon-tube (6 cm long, 2 mm i.d.) packed with sulfite oxidase-bearing Sepharose was used as an enzyme column. The carrier solution was a Tris\u2013HCl buffer of pH 8.2, and 5 mL of the test solution was injected into the carrier stream. Other FIA operation conditions were the same as those described in the oxalate assay. The peak height of the FIA flow signal showed a good linear relation against the sulfite concentration (r \u00bc 0:999) in the range of 1:0 10 6 to 5:0 10 4 M (5 to 2500 pmol per 5 mL injection), and the RSD value was 0.53% (n \u00bc 10, 1:0 10 4 M). By this method, amounts of sulfite in different kinds of foods, such as wines, fruit juices, and dry and frozen foods, were determined. A part of the results are shown in Table 9 . Because of high sensitivity, very small amounts of naturally occurring sulfite contained in fruit juices could be determined by this method. Sugars:33 Determination of sugars is essential for the quality and process assessment in food manufactures. For determining sugars, chromatographic techniques such as GC52 and HPLC,53 enzymatic method54 and FIA method55\u201357 are commonly employed. Among them, FIA method incorporated with an enzyme reactor seems convenient as a simple and rapid means, however, with this method it is rather difficult to determine each constituent sugar continuously. The present FIA method with several enzyme reactors arranged in parallel, in which each flow line was chosen by a switching valve, permitted the continuous determination of glucose, sucrose, maltose and lactose.33 A flow diagram of the FIA system thus fabricated is shown in Fig. 12. A phosphate buffer (0.05 M, pH 6.6) containing 1 mM MgCl2 was served as a carrier solution. Test solution (20 mL) was injected using a sample loop. b-D-Glucose in the test solution was oxidized to form hydrogen peroxide quantitatively by passing through the glucose reactor (E5) packed with glucose oxidase. Sucrose, maltose and lactose (disaccharides) in the test solution were hydrolyzed to form b-D-glucose through their corresponding hydrolysis reactors (E2, E3 and E4, respectively), and the resulting b-D-glucose was converted continuously to hydrogen peroxide through the glucose reactor (E5). Prior to the determination of sucrose, maltose and lactose, glucose in the test solution was removed by passing through the glucose-eliminating reactor (E1) using a switching valve V1. In the reactor E1, glucose oxidase and catalase were packed. In all cases, the effluent hydrogen peroxide from the glucose reactor (E5) was mixed with the Ti\u2013TPyP reagent in the mixing coil, and detected by the measurement of the absorbance at 450 nm. The enzyme mediated reactions for the four sugars taking place in reactors E2\u2013E5 are as follows:"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001349_s0094-114x(00)00051-3-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001349_s0094-114x(00)00051-3-Figure2-1.png",
+ "caption": "Fig. 2. Seven-jointed double-elbow manipulator: (R?R)ptkRkRk(R?R?R)sph.",
+ "texts": [
+ " These degenerate con\u00aegurations and their associated reciprocal screws can be summarized as i S4 0; refWrecip 0; 0; 1; 0; 0; 0f gT; ii S2 C3 0; refWrecip 0; 0; 1; 0; 0; 0f gT ; 21 iii S2 S6 0; refWrecip \u00ffS5; C5; \u00ffC3C4S5\u00ffS3C5 C3S4 ; C5h; S5h; 0 n oT ; iv C5 S6 0; refWrecip \u00ffS5; C5; \u00ffC3C4S5\u00ffS3C5 C3S4 ; C5h; S5h; 0 n oT : Note that the condition sets outlined in (21) are identical to those obtained by Podhorodeski et al. [8] by their decomposition technique. Another seven-jointed manipulator layout is (R?R)ptkRkRk(R?R?R)sph, where pt denotes a pointer joint group and k refers to two successive joints being parallel to one another. This layout is referred to as a double-elbow layout. Denavit and Hartenberg parameters [17] for the manipulator are presented in Table 2. Fig. 2 shows the layout of the manipulator. Choosing a reference frame that is located at the intersection of the wrist spherical group and oriented with xref in the direction of the \u00aenal forearm and yref in the opposite direction of $5 allows the joint screws to be found as ref$1 S234; 0; C234; \u00ffC234f ; C2g C23h C234i; S234ff gT ; ref$2 0; \u00ff1; 0; S34g S4h; 0; C34g C4h if gT; ref$3 0; \u00ff1; 0; S4h; 0; C4h if gT ; ref$4 0; \u00ff1; 0; 0; 0; if gT; 22 ref$5 0; \u00ff1; 0; 0; 0; 0f gT ; ref$6 \u00ffS5; 0; C5; 0; 0; 0f gT; ref$7 C5S6; \u00ffC6; S5S6; 0; 0; 0f gT; where Cij cos hi hj and Sij sin hi hj "
+ ],
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+ "image_filename": "designv11_6_0001183_s0020-7683(00)00010-x-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001183_s0020-7683(00)00010-x-Figure12-1.png",
+ "caption": "Fig. 12. Test rig for cyclic shear test of isolation bearings.",
+ "texts": [
+ " For multiple-layered rubber bearings, the above sti ness must be modi\u00aeed in the same way as the shear sti ness to account for the presence of the steel shims (Kelly, 1993), EIs EI eff h tr : 67 Assigning the dimensions of the circular bearing and the square bearing into Eqs. (64)\u00b1(67), the ratios of bending sti ness to shear sti ness de\u00aened in Eq. (21) are calculated to be q 7:77 for the circular bearings and q 11:78 for the square bearings, which are independent of the material properties. The testing apparatus for the cyclic shear test of isolation bearings is shown in Fig. 12. As the ends of a bearing specimen have to sustain the vertical compressive force and simultaneously allow the horizontal movement at one end during the test, the test rig requires a pair of identical bearing specimens for each test. The lower end of the lower bearing is \u00aexed to the ground and the upper end of the upper bearing is connected to a vertical hydraulic actuator. During the test, the vertical actuator applies a constant compressive force to the bearings. A horizontal hydraulic actuator is connected with the specimens at the junction of the two bearings"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001933_a:1016348803781-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001933_a:1016348803781-Figure1-1.png",
+ "caption": "Figure 1. Two-roller testing machine and dimensions of test rollers.",
+ "texts": [
+ " In order to evaluate the contribution of such micro-pockets separately, in the present paper, using the roller with a small number of micro-dents marked by a diamond pyramid whose total area was, to minimize the effect of work-hardening, set negligibly small compared to the contact area as the follower in a two-roller testing machine, the pitting durability was tested under poor lubrication conditions and/or several loading levels. The result is discussed comparing with electrolytically polished surfaces [4] and tumbled surfaces [5]. The two-roller testing machine used is shown in Figure 1. Load was applied between the contact surfaces of the rollers by using a link mechanism with dead weight. Slip ratio between the rollers was set at \u22120.25 by a gearing having different tooth numbers. Friction force between the rollers were measured by the strain gage pasted onto the torsion bar connected to the follower spindle. The oil film created between two rollers was measured by the electric circuit shown in Figure 2. The exciting voltage applied, E, was 0.1 V. To evaluate the lubrication condition, \u03b5 defined by the time average value of Vc/E is introduced as an index of oil film creation. If the oil film is not created at all, or breaks down completely, the value of \u03b5 approaches 0. If thick oil films are created and asperities do not interact, the value approaches unity. To evaluate the instantaneous oil film breakdown, real time values of Vc/E are also monitored. If the oil film breaks down to yield local severe contact, the instantaneous value of Vc/E approaches 0 at that moment. The dimensions of each roller are shown in Figure 1. The specification of test rollers are shown in Table 1. The equivalent radius of the two rollers is nearly equal to the equivalent radius of curvature of the mating gear teeth used in Refs. [1] and [3]. The slip ratio of \u22120.25 is also nearly equal to the case of gearing in Ref. [1] and [3]. The materials of driver and follower are shown in Table 2. Details of the rollers machined micro-dents are shown in Figure 3. The 4800 dents were formed on the follower surface by a diamond pyramid of micro-Vickers hardness tester"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002406_318-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002406_318-Figure1-1.png",
+ "caption": "Figure 1. Magnet used for the production of a magnetic cluster.",
+ "texts": [
+ " Thus, we can extract the magnetic clusters from the mixing suspension. The last suspension may also be regarded as the most dilute suspension. Anyway, this method can be used to extract the magnetic clusters from any kind of magnetic fluid containing iron particles of any size. Next, we shake the produced suspension of the magnetic clusters in the absence of a magnetic field, because the magnetic clusters are dispersed uniformly in the suspension. We then apply to the suspension a magnetic field of specific strength. Figure 1 shows the magnetic field distribution used in the present test. The suspension is in a vessel. We touch the permanent magnet having a uniform magnetic field intensity region of Hmax out of the surface of the vessel. We can then obtain magnetic clusters of fixed size according to the magnetic field intensity. Figure 2 shows an example of magnetic clusters produced under Hmax = 4100 G as observed via a microscope. The iron used is carbonyl iron HQ (Yamaishi Metal Company, Japan, 20 g) and the magnetic fluid is water-based W35 (35 wt%, Taiho Industry Company, Japan, 10 cc) mixed with 1 g oleic acid Na and 14"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003711_tmag.2006.875997-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003711_tmag.2006.875997-Figure3-1.png",
+ "caption": "Fig. 3. Flux contours at the rated current: (a) healthy motor and (b) motor with 30% eccentricity.",
+ "texts": [
+ " When the rotor is displaced to the stator poles horizontally, the length of gaps between rotor poles and their corresponding stator poles in one half of the rotor surrounding air are reduced, while rising in the other half. According to Fig. 2(b), this leads to the creation of low magnetic reluctance paths for flux. It is whilst; at high current, iron core saturates and its reluctance increases significantly. Hence, variations in air gap lengths do not have a noticeable effect on the total reluctance of the flux paths. So, as seen in Fig. 3, eccentricity cannot affect motor flux pattern considerably, when operating at the high current. 2) Flux-Linkage Profile: Flux-linkage/rotor angular position characteristic is the most important characteristic of the switched reluctance motors. Fig. 4 compares the flux-linkage/rotor angular position characteristic of phase 1 in the healthy motor and the motor with 30% eccentricity at the current equal to 2 A. At higher currents, where saturation gradually appears, flux-linkage characteristic of the healthy motor and the motor with 30% eccentricity are practically identical and are not shown here"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001757_0022-0728(95)03824-z-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001757_0022-0728(95)03824-z-Figure1-1.png",
+ "caption": "Fig. 1. Principal view of the in situ UV visible spectroelectrochemical cell based on LIGA structures as working electrode in a capillary slit.",
+ "texts": [
+ " The use of a L I G A structure as working electrode opens further possibilities of varying cell parameters. The response behaviour becomes more rapid without decreasing the active optical length and the potential control inside the capillary slit is improved. The shorter response time results from the fact that the active optical length is the sum of both the capillary slits between the L I G A structure and the quartz glass spacers and the length of the microholes inside the structure which is equal to the thickness of the structure (called the structure height; see Fig. 1). The conversion time can be decreased by decreasing the capillary slit and the width of the honeycombed holes inside the electrode material. The sensitivity as well as the response behaviour of the L I G A cell depend on the structure height s h which is one part of the active optical length apart from the slits. The ratio between the spacer width and the hole width influences the loss of light intensity at the structure and therefore the sensitivity. Thus the conversion time and the spectroscopic sensitivity can be optimized by the structure parameters hole width, spacer width and structure height as well as by the width of the capillary slit",
+ " The ideal aspect ratio between the inner diameter and the structure height to have a homogeneous potential distribution at the electrode was found to be 1:5. The experimental cyclic voltammetric curves as well as the experimental dependence of the peak current and the peak potential separation are in good agreement with the calculated cyclic voltammograms, with the theoretical dependences of the peak current and the peak potential separation [17]. 2. Experimental The in situ spectroelectrochemical experiments were carried out with a cell (Fig. 1) based on a screw joint of two Teflon parts to hold the L I G A structure and to isolate the non-structured part at the margin [18]. Quartz rods in the bore of the centre of the Teflon parts conduct the light beam through the cell and limit the diffusion layer at the structured part of the working electrode. A silver wire coated with silver chloride was used as a quasi-reference electrode inside the inlet of the cell and a platinum wire in the outlet as counterelectrode. For the cyclic vol tammograms at a planar electrode the same quasi-reference electrode was used which is connected through a salt bridge with a graphite diaphragm containing the same electrolyte as in the cell",
+ " ' //25/zm LIGA r / (optical length 160/~m i \\ 5; ~o ~ / ,ii\\ o., /'\" 50~tm sl i t cel l ~ ~ . 4 / = 2 5 / z m sl i t cell 5 J \\ '\\ ~ . o . . . . t \\ ? , , o 0 ~ , ~ , ~ ~ ~ + , - - 0.0 0 5. I0 , 15 2 0 2 5 3 0 3 5 4 0 t / s . . . . . . I I 115 ' \" ' \" ' ~ . . . . I ' 0 ' ' 115 ' - ~ 0 5 I0 0 5 2 0 trel/S t 25/~m = 2 . 7 s t 50/~m = I I. 5 S Fi~,. 3. C o m p a r i s o n o f the c a l c u l a t e d f a r a d a i c c h a r g e - t i m e curve for a c o n v e n t i o n a l c a p i l l a ~ slit cell a n d for a L I G A cell (Fig. 1 ) wi th the s ame acl ive op t i ca l c ross sec t ion A~ro~ section ~ 3.14 m m 2 (r~o~ ~ section = 1 mm). Slit w i d t h c o r r e s p o n d i n g to the slit b e t w e e n the q u a r t z g lass rods a n d the s t r uc tu r e : cap i l l a ry slit cell, 1110 /zm (curve 1), 50 /zm (curve 2) a n d 25 /zm (curve 3): L I G A cell, 50 ~ m (curve 4) a n d 25 /~m (curve 5). P a r a m e t e r s of the L I G A s t r u c t u r e u sed for the ca l cu l a t i on : Sw = 15 /zm, , % = 2 5 ~ m , S h = 110 /xm, r~,ctiv ",
+ " The time range of the non-lincarity between the electrochemical converted quantity and the absorbance signal caused by the shape of the concentration gradient at net or gauze as well as at minigrid electrodes decreases from 1-2 s to 150-300 ms at L1GA structures. The calculations as well as the experimental results reveal a fast response behaviour of the LIGA cell. The sensitivity and the response behaviour can be influenced by variation of the aspect ratios between the structure height and the inner diameter as well as the inner diameter of the honeycombs and the spacers between them (Fig. 1). The use of all electrochemical and spectroscopic data permits the analysis of complex electrochemical reaction mechanisms and the study of the kinetics of the chemical reactions before and after the heterogeneous charge transfer at the electrode as is shown for the \"self-protonation\" mechanism of the electrochemical reduction of trithioisatoic anhydride\u2022 Summarising, the advantages of the cell are as follows: - - short response and conversion time (intermediates can be detected if they have lifetimes down to 50-100 ms); - - cyclic voltammetric measurements can be carried 1 \u2022 out up to scan rates of 2-5 V s - - the possibility of a quantitative analysis of the cyclic voltammetric curves (comparison of the measured and the calculated curves) as well as the absorbance-t ime curves; - - in situ spectroscopic measurements in transmission at conventional electrode materials used in electrochemistry"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001877_robot.2000.846404-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001877_robot.2000.846404-Figure1-1.png",
+ "caption": "Figure 1: Notation",
+ "texts": [],
+ "surrounding_texts": [
+ "1 Introduction\nA differential drive robot has two independently driven coaxial wheels. It is the configuration used by most wheelchairs, and due to its simplicity is commonly used by mobile robots. By bounded velocity, we mean that the wheel angular velocities are bounded, but otherwise we allow essentially arbitrary motions of the robot. There are no bounds on wheel angular acceleration. In fact, we do not even require that angular acceleration be defineddiscontinuities in wheel angular velocity are admissible.\nThis paper addresses the question: what are the fastest trajectories for a bounded velocity diff drive robot, in a planar environment free of obstacles? Our companion paper [ I] proves that between given start and goal configurations, the fastest trajectories are composed of at most five segments, where each segment is either a straight line or a rotation about the robot's center. This paper completes the analysis of these trajectories.\nWe present an algorithm for computing all optimal trajectories, and show a few plots illustrating the performance limits of bounded velocity diff drive robots.\n1.1 Previous Work\nMuch of the work reported in this paper is a straightforward application of methods developed in the nonholonomic control and motion planning literature. We have found the surveys by Laumond [ 3 ] and Wen [lo] to be\nvery helpful. Most of the work on time-optimal control with bounded velocity models has focused on steered vehicles rather than diff drives, originating with papers by Dubins [2] and Reeds and Shepp [4]. For diff drives, previous work has assumed bounded acceleration rather than bounded velocity. See, for example, papers by Reister and Pin [5 ] and Renaud and Fourquet [6]. Fortunately, the techniques developed for velocity models of steered cars apply readily differential drives. The present paper follows the techniques developed in the papers by Sussman and Tang [9], by Sou5res and Boissonnat [7] , and by Soukres and Laumond [8].\n2 Assumptions, definitions, notation\nThe state of the robot is q = (x, y l e), where the robot reference point (zl y) is centered between the wheels, and the robot direction 0 is 0 when the robot is facing parallel to the z-axis, and increases in the counterclockwise direction (Figure I). The robot's velocity in the forward direction is v and its angular velocity is w. The robot's width is 2b. The wheel angular velocities are wl and w,.. With suitable choices of units we obtain\n0-7803-5886-4/00/$1 O.OO@ 2000 IEEE 2499",
+ "W\nand\nThe robot is a system with control input w(t) = (w l ( t ) , w7.(t)) and output q( t ) . Admissible controls are bounded Lebesgue measurable functions from time interval [0, T ] to the closed box W = [-1,1] x [-ll 11\nThe admissible control region W provides a convenient comparison with previously studied bounded velocity models. If we plot W in U-w space, we obtain a diamond shape. Steered vehicles are typically modeled as having a bound on the steering ratio w : \u2018U, and on the velocity \u2018U (Figure 2). We also need notation for trajectory types. We will use the symbols fi, 4, .A, and n, to denote forwards, backwards, left tums, and right turns. A trajectory of several segments is indicated by a string. Thus, for example, fin40 means a motion of four segments: forward, right tum, backward, left turn.\n3 Time cost of saturated trajectories\nWe define a saturated trajectory to be one for which the input w(t) is at the boundary of the box W over the entire trajectory. That is, at almost all times either w, or WI is at the limit. We define rectified arc length in the plane of robot positions\n( 5 )\nand in the circle of robot orientations\nFor a saturated trajectory, it is easily shown that\nlvl + blwl = 1 (7)\nalmost everywhere. Integrating this equation yields\ns ( t ) + ba(t) = t (8)\nThus the time for a saturated trajectory is just the sum of the arc length in E2 and the arc length in S\u2019 scaled by the robot radius b. This suggests that to minimize the time we ought to turn in place or make straight lines. Our companion paper [ l ] proves that this is indeed the case using Pontryagin\u2019s maximum principle.\n4 Controllability. Existence of optimal controls. Extremals.\nThis section summarizes the results of our companion paper [l]. The bounded velocity diff drive is globally controllable, and time optimal controls exist. Pontryagin\u2019s Maximum Principle yields necessary conditions for time optimal controls. The trajectories satisfying these conditions are thus a superset of the time optimal trajectories, and are called the extremal trajectories. Using additional necessary conditions an enumeration of extremals is obtained.\nThe extremal trajectories can be expressed as a geometric program, using a construction called the 7-line. It is a directed line in the plane, which divides the plane into a left half plane and a right half plane. Pontryagin\u2019s Maximum Principle implies that for any optimal trajectory there is an 7-line such that the trajectory can be achieved by a control of the form:\nW l { = l E [-1,1] if right wheel is on the line (9)\nW T { = l E [-ll 11 if left wheel is on the line (10)\nif right wheel E right half plane\nif right wheel E left half plane\nif left wheel E left half plane\nif left wheel E right half plane\n= -1\n= -1\nThe behavior of the robot falls into one of the following cases (see Figure 3):\n0 CCW and CW: If the robot is in the left half plane out of reach of the v-line, it turns in the counter-clockwise direction (CCW). CW is similar."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002044_s0378-4754(02)00027-7-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002044_s0378-4754(02)00027-7-Figure7-1.png",
+ "caption": "Fig. 7. Orientations to test the door-confirmation module.",
+ "texts": [
+ " After a lot of experimentation, we conclude that the door-recognition vision module works well under stable light conditions; variations in brightness and reflections alter notably the results of the vision module. In spite of this, when light conditions are adequate the vision module helps gratefully to identify door candidates and to reject false ones. For proving the door-confirmation module, we placed our B21 robot in several positions about 95 cm away from the door. Different headings have also been taken into account from each position as shown in Fig. 7. V1 and V3 correspond to the robot heading towards each edge of the door, and V2 represents that the robot is heading to the center of the door. Table 1 shows the percentages of success obtained from each position. The meaning of each Pi position is represented in Fig. 8. It can be deduced that this module works well between the incidence angles we used for training (less than 30\u25e6 from door center and 1 m far). It also works fine for no-door recognition. Door and no-door cases were clearly differenced"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001909_20.250667-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001909_20.250667-Figure6-1.png",
+ "caption": "Fig 6. The mesh generated",
+ "texts": [
+ " It has 48 slots on the stator and the three phase winding is identical to that of figure 2 except that it contains 4 slots per pole per phase. The representation of the whole stator would be difficult. This is why, we used the results already obtained. The stator has been supplied with a homopolar system of currents so that only one sixth of the machine needs to be represented. Figure 5 shows one portion of the magnetic circuit of the stator. the end windings of the machine and the current density in the end windings. The boundary conditions used to compute the vector potential are Dirichlet on all faces surrounding the machine. Figure 6 shows the mesh generated by FLUX3D. The reactances of the end windings have been compared against analytical formulae used by the manufactuer. Table I shows the results. The error E of 8.2 % is acceptable since we do not know what is the true value. Iv. TWO POLE MACHINE The last machine under investigation was a two pole induction machine stator with 24 slots and a 3 phase winding. This means 4 slots per pole per phase. Figure 7 represents the winding. In this case the simplification of a homopolar supply is no longer valid because the geometry of the winding does not allow such simplification"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001423_s1350-4533(99)00095-8-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001423_s1350-4533(99)00095-8-Figure2-1.png",
+ "caption": "Fig. 2. The kinematic model of the finger segments allows the coordinates of a point on the fingertip (inset, arrow) to be estimated with respect to the metacarpal bone (coordinate-system-0). The axis of MCP abduction/adduction (z0) does not intersect the axis of MCP flexion/extension (z1), because the MCP joint has different radii of curvature for these two movements (left). Each of the x-axes (x1\u2026x3) are chosen to point distally along the long axis of the bone, on a line which intersects the next-most-proximal axis. The axis x0 is chosen to intersect z1 at a right angle when the finger is straight. As shown (right) adjacent coordinate systems are related by rotations (qMCPa\u2026qDIP) and displacements (a1\u2026d4).",
+ "texts": [
+ " The Nomenclature ip \u2192 tip Coordinates of finger tip expressed with respect to coordinate-system-i ip \u2192 LUMo Coordinates of origin of lumbrical muscle ip \u2192 ins Coordinates of insertion of lumbrical and radial interosseous on extensor hood ip \u2192 rIOSSo Coordinates of origin of radial interosseous muscle on metacarpal bone qMCPa MetaCarpoPhalangeal joint abduction (about z0) qMCPf MetaCarpoPhalangeal joint flexion (about z1) qPIP Proximal InterPhalangeal joint flexion (about z2) qDIP Distal InterPhalangeal joint flexion (about z3) ,FDS Length (excursion) of Flexor Digitorum Superficialis muscle ,FDP Length (excursion) of Flexor Digitorum Profundus muscle ,EDL Length (excursion) of Extensor Digitorum Longus muscle ,LUM Length (excursion) of LUMbrical muscle ,rIOSS Length (excursion) of radial InterOSSeous muscle ,uIOSS Length (excursion) of ulnar InterOSSeous muscle i\u22121Ti Homogeneous transform from coordinate-system-i to i21 || ||2 Second (Frobenius) norm of a vector, \u221ax2+y2+z2 for [x y z]T radial and ulnar InterOSSeous (rIOSS, uIOSS) muscles originate on the lateral aspects of the metacarpal, and insert on either side of the extensor hood. These two muscles primarily produce abduction/adduction movements about the MCP joint. However, they also change length with MCP joint flexion. We used a kinematic model of the finger segments [2] to estimate the coordinates of a point on the finger tip (Fig. 2, inset) with respect to the metacarpal bone. The axes (z0\u2026z3) represent the axes of rotation of the finger joints for movements of MCP abduction, MCP flexion, PIP flexion, and DIP flexion (Fig. 2, left). The model describes the finger as a set of pin joints separated by links of fixed length (a1\u2026d4) (Fig. 2, right). Although the model allows for non-parallel flexion axes, our apparatus for estimating finger pose could not measure skew angles. Therefore, the flexion axes of the finger joints are assumed parallel. Anatomical data [11] indicate that this assumption, which has been incorporated into many models of the finger [3,6,9,10], is reasonable. The axis of MCP abduction/adduction is taken to be perpendicular to the axis of MCP flexion. The parameter a1 sets the distance between the axis of MCP joint abduction and the axis of MCP joint flexion. The axes do not intersect, because the metacarpal head has a different radius of curvature for each of these movements. The parameter d2 approximates the distance between the axis of MCP flexion and the axis of PIP flexion. The parameter d3 approximates the distance between the axis of PIP flexion and DIP flexion. The parameter d4 approximates the distance from the axis of DIP flexion to a point on the fingertip (Fig. 2, bold arrows). The axes (z0\u2026z3) and the segments corresponding to the shortest distances between them (a1, d2, d3) suggest coordinate systems (Fig. 2, left). A left superscript indicates the coordinate system in which a point is expressed. For example, 3p \u2192 indicates a point expressed with respect to coordinate-system-3, which is fixed in the head of the middle phalanx (Fig. 2, left). The z-axis of this coordinate system is coincident with the axis of rotation of the DIP-joint. The x-axis points distally along the long axis of the bone, and lies on a line which intersects the next-most-proximal coordinate system. Coordinate system-2 and coordinate-system-1 are defined in the same way. Coordinate-system-0 is fixed with respect to the metacarpal bone. The z-axis of this coordinate system is coincident with the axis of the MCP abduction/adduction. The x-axis is chosen to intersect the z-axis of coordinate-system-1 at a right angle when the finger joints are straight",
+ " Based on manufacturer\u2019s literature, the measurements of IRED coordinates had accuracy of \u00b10.15 mm, and precision of \u00b10.015 mm. Offline, the coordinates of the IREDs were used to estimate the abduction (qMCPa) and flexion (qMCPf) angles of the MetacarpoPhalangeal joint, as well as the flexion angles of the Proximal InterPhalangeal joint (qPIP), and Distal InterPhalangeal Joint (qDIP) (Fig. 8, inset). The offset from the center of the most distal IRED (Fig. 8f) to the point on the finger tip indicated by the arrow (Fig. 2, inset) was measured with approximately \u00b10.5 mm precision with a ruler and protractor prior to data collection. Further references to \u201cthe location of the finger tip\u201d refer to this point, selected to approximate the center of the fingertip contact area during precision pinch, and the most distal portion of the finger pad in contact with an object during power grasp. The following tendons of the finger were attached to thin, woven-wire cables loaded through a system of pulleys and weights with forces (9",
+ " Poses which can only be achieved by imposition of an outside load (qDIP.qPIP) were included in the set. Based on 100 randomly selected pairs of measures taken at identical poses (that is, all joint angle measurements matching within 0.01\u00b0), estimates of marker locations were repeatable with an average precision of \u00b10.23 mm, with no pair of repeated measures disagreeing by more than 1.50 mm. The calibrated kinematic model approximated the x, y, and z-coordinates (Fig. 9, top row) of the finger tip (Fig. 2) with satisfactory precision (RMS error=1.41 mm). The forward kinematic model accounted for nearly all of the variance in finger tip coordinates (VAF%=99.09). The precision of the model was comparable to that achieved for kinematic calibration of the finger of a living subject, using a different apparatus to measure finger pose (RMS error=1.42 mm) [2]. Parameters for estimating kinematics of the finger segments appear in Table 1. Excursions of the three extrinsic muscles (Fig. 9, middle row) were also well approximated"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002294_a:1005694704872-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002294_a:1005694704872-Figure1-1.png",
+ "caption": "Fig. 1. The thick-film electrode consists of 3-electrode system. The enzyme is immobilized on the working electrode in the indicating window.",
+ "texts": [
+ " Measurements were carried out with an electrochemical detector (Biometra EP-30) coupled with a computer. A 25 ml beaker was used as a measuring cell at room temperature (21 \u25e6C), with a magnetic stirrer assuring perfect stirring of the background solution. Disposable thick-film platinum electrodes from SensLab GmbH (Leipzig, Germany) were used, which are composed of a three-electrode arrangement of working and counter electrodes with applied potential at +400 mV against internal Ag/AgCl reference electrode (Figure 1). The prepared sensor was vertically arranged in the measuring cell. Sensor responses were measured by allowing 10 ml phosphate buffer solution to equilibrate with atmospheric oxygen (steady-state current), and then injecting various amounts of sample solution to achieve different analyte concentration in the measuring cell. The sensor response was recorded as the difference in current change (end-point detection). Between measurements the cell was rinsed twice with distilled water. When not specified, the sensor was stored at 4 \u25e6C in moisture condition (tight bottle with wet tissue inside) when not in use"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002068_bf00052455-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002068_bf00052455-Figure2-1.png",
+ "caption": "Fig. 2. Rigid body model [20].",
+ "texts": [
+ " Application fields are drivelines of large diesel engines, which due to a large temperature operating range usually are designed with large backlashes [1, 20]. The dissertation [20] represents the newest state of research and will be the basis of this paper. The plenary lecture [19] gives a survey on dynamical systems with time-varying or unsteady structures. Rigid bodies are characterized by six degrees of freedom, three translational and three rotational ones. We combine these magnitudes in a l~6-vector (Figure 2 and [20]) ( 6~ ) EIl~6 (1) P = rH with (~ -~- ( ~ x , ~ y , ~ z ) T, rH = ( A x H , / k y H , A Z H ) T E R 3. (2) Accordingly, the velocities are v = bH = VH ~ (3) Elastic bodies in gear or driveline units usually are shafts with torsional and/or flexural elasticity. In the following we consider only torsion by applying a Ritz approach [18] to the torsional deflection ~ (Figure 3): ~(z , t ) = W(z)Tqel(t) with w,q~l C ]~7~ (4) where the subscript \"el\" stands for \"elastic\". used in multibody theory [3] the free directions f i of motion of a joint i are given with a matrix ~i C ~6,fi",
+ " It starts with d'Alembert's principle which states that passive forces produce no work or according to Jourdain generate no power [3, 18]. This statement can be used to eliminate the passive forces (constraint forces) and to generate a set of differential equations for the coupled machine system under consideration. We start with the equations of motion for a single rigid body. Combining the momentum and moment of momentum equation and considering the fact that the mass center S has a distance d from the body fixed coordinate frame in H (Figure 2) we come out with where I = d = IH = --fK ~- fs= ( I. ma ) 1 6,6 -racl mE~ E (0, O, d) T E ll~ 3 diag (A, A, C) C I~ 3'3 ~ T T [(~JiH~-~e3) ,0] C ~6 The magnitudes A, C are moments of inertia, ft,\" are gyroscopic, fB acceleration and fE applied forces, f2, (~ are prescribed values of angular velocity and acceleration, respectively. The unit vector e3 is body-fixed in H (Figure 2). By adding components with torsional elasticity we can expect an influence on the rigid body motion only with respect to the third equation of (11). Therefore torsional degrees of freedom can be included in a simple way. The equation of motion for a shaft with torsional flexibility is 0 ~ 0 [ G I p ( Z ) ~ z J - M k ~ ( z - z k ) =0. (13) pip(z) ot 2 Oz (p density, Ip area moment of inertia, G shear modulus, Mk torque at location zk). The total angle ~ has three parts t) = f f~(t) dt + p~(t) + 9~(z, t), (14) ~(z, where ~(t) is the angular velocity program, ~ (t) the z-component of ~I, (equation (2)) and ~(z, t) the torsional deflection (Figure 3)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000637_ac960779o-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000637_ac960779o-Figure2-1.png",
+ "caption": "Figure 2. Actuated, optical transmittance flow cell. (a) Perfusion and monitoring of an entrapped bead layer. (b) Ejection of spent beads to waste.",
+ "texts": [
+ "; Chowdhury, D. A.; Kamata, S. Anal. Chem. 1994, 66, 1713-7. (6) Riddick, J. A.; Bunger, W. B.; Sakano, T. K. Organic Solvents, 4th ed.; Wiley & Sons: New York, 1986. Anal. Chem. 1997, 69, 1763-1765 S0003-2700(96)00779-2 CCC: $14.00 \u00a9 1997 American Chemical Society Analytical Chemistry, Vol. 69, No. 9, May 1, 1997 1763 An actuated, optical transmittance flow cell was designed for trapping, perfusing, and monitoring beads. Trapped bead layers in the flow cell were perfused while monitoring with fiber optics (Figure 2a) and then ejected to waste (Figure 2b). A difference of one drill size between the rod in Figure 2 and the FEP fluorocarbon block material of the cell was narrow enough to allow solution to flow around the rod while the bead layer was retained. The rod was made of poly(ethyl ether ketone) (PEEK) and was actuated by two solenoids (intermittent-type, 24 V, Guardian Electric, Woodstock, IL) to move 1 mm so that it either blocked or cleared the 0.8 mm diameter flow channel. A PTFE sheet drilled out two drill sizes smaller than the rod served as a gasket. The holes accommodating the fibers were drilled to within 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001062_s0167-7799(98)01243-8-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001062_s0167-7799(98)01243-8-Figure2-1.png",
+ "caption": "Figure 2 The structure of an integrated enzymic microbattery. The close-up shows the electrodes with immobilized glucose oxidase (a,b), the ion-exchange membrane (c) and platinum electrodes deposited on the silicon-wafer substrate (d). The cells are all connected in series.",
+ "texts": [
+ " The techniques used to fabricate the microbiosensors could also be applied to the enzyme battery, and an integrated enzyme battery has indeed been fabricated by methods such as anodic bonding and anisotropic etching9\u201311. If an enzyme battery could be fabricated using micromachining techniques, it might be implanted inside the human body and use organic compounds as a fuel. This would be an ideal device for the future microsurgery robot. We have attempted to make an integrated enzyme battery in which between two and six cells were connected in series12. All these individual cells were fabricated on a single silicon wafer and glucose solution was introduced into the cell by the capillary effect (Fig. 2). The electrical-power output of this enzyme battery was found to be several Watts. In addition, by connecting the cells in series, high voltages could be gained (a higher voltage is preferable for an electrostatic micromotor, which must produce a propulsive force for the robot). So far, such a microbattery has problems of lifetime and stability but, by applying the knowledge from the development of biosensors, these should be overcome in the near future. 1 Adlhart, O. J., Rohonyi, P., Modroukas, D"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001615_0263-8223(93)90220-k-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001615_0263-8223(93)90220-k-Figure8-1.png",
+ "caption": "Fig. 8. Configuration of the valve spring retainer.",
+ "texts": [
+ " This Change of dynamic modulus and damping at 100 N/mm 2. situation in cross-ply laminates is called the 'characteristic damage state'} The edges of the transverse cracks rub against one another and in doing so raise the energy loss. After a while the crack edges become smooth and the frictional losses decrease. Thus, damping decreases after cracking stops, because no more rubbing surfaces are created and the frictional loss per unit of crack area decreases. A valve spring retainer is a very intense accelerated motor component (Fig. 8). Therefore, it is possible to increase the critical number of revolutions with a mass reduction of this part. The tested part was a 1 : 1 substituent of the retainer made of steel, but its weight was only 3.6 g instead of 17 g? 0.16 - 0.12 0.08 0.04 2 e amox = 40 N / m m 2, emox = 0.4% i mama x 30 N / m m 2, Emax 0.3% ! \u2022 amox 20 N / r a m 2, Emox 0.2% I \u2022 f\\. / ..t \".,,.. /..,, / OCJP m mm ~mmmmm mlmm'm\" mnJm ~ dm \u2022 vvV tvw vvlnV vVv~v I I I I 3 4 5 6 Number of oyeles [log N] Fig. 7. Change of damping at different stress levels"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003897_009-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003897_009-Figure2-1.png",
+ "caption": "Figure 2. Sketch of the experimental geometry.",
+ "texts": [
+ " To elucidate the physical impact of ion-number conservation in the electrowetting of immiscible-electrolytic solutions, we first explore the electrostatics with idealized droplets of fixed shape. The most easily tractable case is a hemispherical droplet, for which exact solutions to the linearized PB equations can be obtained. This section provides the potential and charge distributions for polarized hemispherical droplets in three regimes of size, and determines the ranges of droplet radius over which each asymptotic result is most accurate. A hemispherical droplet is taken to lie between two parallel planar electrodes separated by distance L, as shown in figure 2. The electrode on which the droplet sits is assumed to be an ideal conductor, and thus is an isopotential surface at potential 0. The droplet has a radius of curvature rd. Let z designate the distance perpendicular to the near electrode through the axis of symmetry. We assume the interelectrode distance L rd, making the system semi-infinite with \u2192 0 as z \u2192 \u221e. Designate the phase within the droplet by d and the surrounding phase by s, and the corresponding potentials by d and s. In spherical coordinates, this system is insensitive to the azimuthal angle \u03c8 because it is rotationally symmetric about the z-axis; the potential in phase j , j , depends on the radial coordinate r and polar angle \u03b8 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003711_tmag.2006.875997-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003711_tmag.2006.875997-Figure2-1.png",
+ "caption": "Fig. 2. Flux contours at 10% of the rated current: (a) healthy motor and (b) motor with 30% eccentricity.",
+ "texts": [
+ " It is observed that at the low current, ec- centricity clearly affects the flux pattern, while this is not the case at the high current. The reason is that there is no iron core saturation at low current and then, flux path reluctance is mainly determined by the length of the air gap. When the rotor is displaced to the stator poles horizontally, the length of gaps between rotor poles and their corresponding stator poles in one half of the rotor surrounding air are reduced, while rising in the other half. According to Fig. 2(b), this leads to the creation of low magnetic reluctance paths for flux. It is whilst; at high current, iron core saturates and its reluctance increases significantly. Hence, variations in air gap lengths do not have a noticeable effect on the total reluctance of the flux paths. So, as seen in Fig. 3, eccentricity cannot affect motor flux pattern considerably, when operating at the high current. 2) Flux-Linkage Profile: Flux-linkage/rotor angular position characteristic is the most important characteristic of the switched reluctance motors"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.14-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.14-1.png",
+ "caption": "Figure 3.14. Euler angles and rotations.",
+ "texts": [],
+ "surrounding_texts": [
+ "It was shown in Section 2.7 that consecutive infinitesimal rotations are vectors; and their composition, therefore, is both additive and commutative. We are now able to show that the same result may be derived from (3.147b )."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001429_robot.1989.100102-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001429_robot.1989.100102-Figure3-1.png",
+ "caption": "Figure 3. Top View and Side View of Two Fingers Grasping a Spherical Object. (I=inertial, O=reference member, B=base, and C=contact coordinate frames.)",
+ "texts": [
+ "9 nt-m 5 5 0.9 nt-m, -1.8 nt-m 5 r2 5 1.8 nt-m, -1.8 nt-m 5 r3 5 1.8 nt-m. For simplicity of presentation only two fingers are first used to manipulate a very dense 2 lb. spherical object which has a radius of 1 inch. Simulation results for the 4-finger case are also obtained and presented later in the paper. Hard point contact with friction is assumed. A circular, simple harmonic motion with respect to the vertical axis is planned. This motion is 30' in magnitude and 2 cycles per second in frequency. Figure 3 shows the top view and side view of the mechanism a t the neutral position of the motion. After briefly presenting the model used to describe the mechanism, the known components (W, F, A, B, and C) in the force distribution problem will be determined next. This will be followed by the approach taken to obtaining the general solution of Eq. (2), for this case. B. Obtaining the Known Components in the Force Distribution Problem In (41, an efficient formulation of the force distribution equations, for simple closed-chain robotic mechanisms, has been developed",
+ " (2), we have 1 0 0 0 1 0 0 0 Oy1 0 0 0 - -0y1 0 0 w = 0 0 1 1 0 0 0 1 0 0 0 1 0 0 oyz 0 0 0 -0y2 0 0 F = (fingers) are in frictional contact with it. The case of 2 fingers is considered ( m = 2), and each finger has 3 degrees of freedom ( N = 3). Also, for hard point contact with friction, 3 degrees of constraint are imposed at the contact points (d = 3). For this example, a reference member coordinate frame (0) is defined with its origin at the geometric center of the object. The unit vector \"y aligns with the line passing through the contact points C1 and Cz, and the unit vector O i points upward. (See Fig. 3.) As was mentioned previously, since point contact is assumed, G has only force components. If G is expressed with respect t o reference member coordinates, then Eq. (2) can be decomposed into two parts (see later discussion). This results in the following -Of' - 0 O f Y 0 . (38) 8.91 nt 0 2 O l f = 0 O n Y 0 O n z ~ 0.0194cos4at nt-m force balance equations: - 1 0 0 0 1 0 0 0 1 0 0 oy1 0 0 0 - O Y 1 0 0 1 0 0 - - o f : - - Of\" - 0 1 0 of: O f Y 0 0 1 \" f i \"= f 0 2 0 0 O Y 2 \"fi\" 0 2 1 0 0 0 of; nu -0yz 0 0 \"fi\" - O n z - where O f 1 = [\"fr Of: contact force vector at C1 onto reference member expressed in reference member coordinate frame, = [\"f; Of; of;]T, contact force vector at C, onto reference member expressed in reference member coordinate frame, oylf'yz) = y component of the position vector to C1 (Cz) expressed with respect to reference member coordinate frame, O f = [\"f\" \"fY 'PIT, resultant force vector onto O f ",
+ " G Irm,,, -JT. G 5 -rmin, where J is the composite matrix, whose dements are the Jacobians for the chains, and which relates the finger contact forces to the joint torques. Also, T~~~ (rmin) is the vector of the maximum (minimum) actuator torques. Combining Eqs. (46), (47), and (48) we have: In fact, Eq. (49) is equivalent to Eq. (3) so that A = [ 9 (49) with rm, = [ 0.9 1.8 1.8 0.9 1.8 1.8 I T nt-m, (52) and rman = -Tmax. (53) To maintain contact, Of: should be positive and Of,\" negative (see Fig. 3). Therefore, in order to prevent crushing of the object, the objective function is specified as: @ = C . G (54) C = [ O -1 0 0 1 0 1 (55) where so that the normal components of the contact forces at the local surface are minimized. 948 and Let W\" = [ \"i, ] and (59) -0y1 0 -\"y2 0 Since 2 distinct contact points are considered, \"y1 # Oyz. Therefore, the rank of W\" is 2 and that of Wxy is 3. Equation (56), then, may be used to solve for the z components of the forces. Equation (57), on the other hand, has 4 variables in 3 equations, therefore multiple solutions exist"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001834_cp:20000267-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001834_cp:20000267-Figure1-1.png",
+ "caption": "Fig. 1 Single-phase brushless dc motor andH-bridge inverter.",
+ "texts": [
+ " In literature [ l - 41, whilst the starting torque of 1-ph BLDC motors was studied extensively, the influence of winding inductances on their torque capability has not been addressed. In order to maximise the motor power density and to minimise the motor peak phase current so as to reduce the power device ratings for high-speed applications, two alternative commutation strategies are studied, one using the phase commutation advancing technique and another using the conducting pulse-width control. The paper describes the techniques and reports the corresponding simulated and measured performance. DESCRIPTION OF MOTOWRIVE SYSTEM Fig. 1 shows the prototype 2-pole, 1-ph BLDC motor, its rotor having isotropic, surface-mounted, bonded NdFeB magnets, having ~ 6 0 % by volume loading of NdFeB powder and an outer carbon fibre wrap of 0.5\" thickness. The magnets have a remanence of 0.5T and a relative recoil permeability of 1.19, and are impulse magnetised. The stator laminations are TRANSIL335, and in order that the motor could be retrofitted to the vacuum cleaner, the axial length and outer diameter of the stator were constrained to be 87.5\" and 76\". respectively, to accommodate the existing impeller and mounting. The open-circuit field distribution is shown in Fig. 1. Single-phase motors can exhibit null-points in their torque waveforms, which can make them difficult to start. To overcome this problem, an asymmetrical graded airgap is employed in the prototype motor to introduce a cogging torque component, which complements the excitation torque and results in a net unidirectional total torque, and to impart a preferred direction of rotation. Fig2 compares the finite element predicted and measured cogging torque waveforms, whilst the measured and finite element predicted backemf waveforms are shown in Fig",
+ "(nd) For very low power applications, in order to reduce the cost of the power devices it is common to use the unipolar inverter [l-31 in which only two power switching devices are required. However, this type of inverter cannot fully utilise the copper and the power density is very low since the phase winding only conducts for half cycle. For relatively high power Power Electronics and Variable Speed Drives, 18-19 September 2000, Conference Publication No. 475 Q IEE 2000 applications a bipolar converter, i.e. H-bridge, as shown in Fig.1, is necessary so that the phase winding will conduct over 180\u2019 for both positive and negative cycles. A Hall sensor can be used for rotor position monitoringkommutation, and the motor was supplied from a MOSFET converter and a simple controller via a rectifier/filter from the single-phase mains power supply. DYNAMIC SIMULATION MODEL The electromagnetic equations for single-phase brushless dc drive are relatively simple, the supplied motor terminal voltage is determined from the commutation strategy and is governed by: di(t) vmOtor ( t ) = e(t) + R ",
+ " As the speed increases, the torque capability is reduced considerably, whilst the proposed two methods show significant improvement and hence they are suitable for high-speed, high power density and low cost applications. 3 2 I I I 1 1 S o c t 5 -1 0 I -2 ! I I I I i -3 4 I 0 0.01 0.02 0.03 0.04 Time (s) (a) conventional commutation, 7 m \" 8 6 4 2 0 -2 -4 4 -8 0 0.01 0.02 0.03 0.04 T i (s) (b) 300 advanced commutation/1800 conduction period, 230m\" 2 1 z g o 6 E 1 I -2 4 4 0 0.01 0.02 0.03 0.04 \" (9 (c) Pulse-width controY12oO conduction period, 14m\" Fig. 1 1 Measured and simulated current waveforms at 5,000rpm and 50V dc link voltage. 0.3 . - E 0.25- z 2 0.2 I- 0.15 - 0.1 0.05 - \\ U 0 A I A 0 0 5ooo loo00 15ooo 20000 speed (W) Fig. 12 Measured and simulated torque-speed characteristics under 120' pulse-width control. 33 1 It has been shown in the previous sections that the optimal advanced commutation angle and the optimal pulse-width depend on the winding inductance and the motor operating speed. It is not difficult to implement the optimal values by using a micro-processor or DSP"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003257_tro.2005.844679-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003257_tro.2005.844679-Figure2-1.png",
+ "caption": "Fig. 2. Convention for direction of friction cones in grasping and force triangles/tetrahedra in cable robots.",
+ "texts": [
+ " Thus, form closure, which is usually more difficult to analyze, deals with kinematic constraints, while force closure deals with force-moment constraints. It is well known, as discussed in detail by Mason [14], that force closure does not entail form closure and neither does form closure entail force closure. In other words, force closure does not guarantee full kinematic constraint or vice versa. This paper deals exclusively with force constraints, thus, force closure. For readers interested in analyzing form closure, we recommend two papers by Rimon and Burdick [16], [17]. shown in Fig. 2(a), where the light triangle (planar cone) points away from the finger. This convention is strictly employed throughout this paper. Equivalently, when examining the set of forces that can be generated by a set of coincident cables in a cable robot, we define the resulting half-open triangle (in two dimensions) or half-open tetrahedron (in three dimensions) to always be drawn such that the forces that the cables can apply point away from the cable intersection point. This convention is illustrated in Fig. 2(b) for two coincident cables. Two different cases are shown in Fig. 2(b): For the case where the cables coincide at the moving platform, the location and direction of the light triangle is obvious, while it is less obvious if the cables coincide at the motor location. A planar cable robot must use at least four cables to achieve force closure. Furthermore for mechanism symmetry, kinematic simplicity, and wire tangling, it is beneficial to use only two attachment points on the moving platform, i.e., two pairs of cables that coincide at the platform. An example is shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000666_bit.260460310-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000666_bit.260460310-Figure2-1.png",
+ "caption": "Figure 2. Effect of PEI addition to the paste on the current response to 5 mM D-lactate and 0.1 mM NADH and the response change during storage. Paste composition per 100 mg graphite powder: 0.87 mg D-LDH, 75 mg N A D + , 3.5 mg redox polymer, and 40 pL paraffin oil; carrier: 0.25 M phosphate buffer, pH 7.0; flow rate: 0.84 mL min- '; injection volume: 50 JLL; applied potential: - 50 mV vs. Ag/AgCl (0.1 M KC1).",
+ "texts": [
+ " However, because of the versatility of possible additives and the lack of fundamental knowledge of how these may affect the system, PEI was chosen as a model additive in this study because of its previously shown general beneficial proper tie^.^\"^ Even though a very dramatic increase in the number of papers describing enzyme, tissue, and whole cell modified carbon paste electrodes is seen during last few years, lo the basic understanding of the electrochemistry as such and how deep substrate and other compounds from the contacting solution may penetrate the paste is virtually unknown today. '' Figure 2 shows the responses of two equally prepared pastes (0.44 mg of LDH, 75 mg of NAD+, and 3.5 mg of redox polymer, per 100 mg of graphite powder with 40 pL of paraffin oil) with the exception that to one paste 100 pL of 0.2% PEI were added per 100 mg of graphite. The responses to 5 mM D-lactate and 0.1 mM NADH, respectively, were 24% and 18% higher registered for the paste electrodes incorporating PEI. This strongly suggested a positive effect of added PEI on the response. Comparing the shape of the flow injection (FI) peaks obtained, one could note a slightly faster response for the PEI-modified paste, revealed by less width at half height and less tailing",
+ "5 mg of redox polymer per 100 mg of graphite powder was chosen. Some sensor characterization can be obtained when replotting calibration data in the form of an electrochemical Eadie-Hofstee plot. l7 The general equation is j = j,,, - KMaPP (i/C) (2) where j is the current density obtained after the addition of substrate and C is the bulk concentration of substrate. Results from an electrode with 50 mg of NAD+ ,0.87 mg (374 U) of D-LDH, 3.5 mg of redox polymer, and 100 pL of 0.2% PEI per 100 mg of graphite powder using the same measuring condition as in Figure 2 are plotted (data not shown), revealing aj,,, of 230 p A cm-* and an apparent Michaelis-Menten constant (KMapp) of 5.6 mM. This indicates that the electrode is suitable for analysis of D-lactate for concentration approximately <0.1 KMaPP for which a straight calibration curve is obtained. The free dissolved form of the enzyme from the same species of bacteria has a K, of 2.2 mM for D-lactate in 0.1 M Tris-HC1 buffer at pH 8.7, 25\u00b0C.6 Possible explanations to the discrepancy between these values may be that there exists an increased diffusional barrier at the electrode-solution interface or that the high content of NAD+ in the paste affects the constant",
+ "\u2019 A positive stabilizing effect of the enzyme in the electrode by addition of PEI is expected. After 4 days storage, a similar response decrease of around 17% was observed in 5 mM D-lactate for all electrodes irrespective of the presence or absence of PEI. However, the response of PEI-containing electrodes decreased 43%, but the electrodes with no PEI only decreased 22% of its initial re- sponse after 1 week storage. A decline of around 50% was seen for both types of electrodes after 29 days of storage (Fig. 2). From the data collected above, it seems that the addition of PEI has no effect on the storage stability of this electrode, although some positive effect has been shown in another study.\u2019 Covering the CP electrode with a membrane would impose a barrier to include the water-soluble components in the paste during measurement. In addition, electrode fouling may be prevented, l 1 interferences e ~ c l u d e d , ~ and the linear response range extended,21 but at the expense of sensitivity. An Eastman AQ cation-exchange membrane was proven beneficial in a previous investigation of a glucose sensor based on glucose dehydr~genase"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001980_robot.1995.526028-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001980_robot.1995.526028-Figure2-1.png",
+ "caption": "Figure 2 - A Spatial Contact",
+ "texts": [
+ " Our procedure is particularly applicable in the case of enveloping grasps; it is, however, applicable in all grasps, enveloping or not. 2. Modeling and Problem Formulation Consider Figure 1. Let nf be the number of independent fingers in contact with the grasped object, and let \u2018nc be the number of contacts on finger i. The superscript \u201ciJ\u2019 is used to denote the j f h contact on the ith finger. Further, let np be the number of contacts with fixed surfaces, and let the superscript \u201cl\u201d denote the l fh contact with a fixed surface. In Figure 2, we consider a contact between a grasped object and a finger. If the bodies are perfectly rigid we can define the contact point which is the coincidence of two points, iJJoB fixed to the grasped object and i\u2019JoA fixed to the finger. Because all real bodies are not perfectly rigid the contact will occur over a small but finite area. However it is still possible to define the points \u2018PJoA and i,JoB as the points at the centroid of the contacting surface [9]. The point i j ~ A is used to define the origin of moving coordinate frame attached to the finger",
+ " Similarly, we can use a linear tangential spring perpendicular to the contact normal and a linear rotational spring about the normal, with spring constants k, and ke, respectively. Consider an individual contact between a finger and the grasped object. A second order model describing the surface of the finger is given by [lo]: where X A and y A are aligned with the principal axes of curvature of the finger, KUA is the curvature along the xA axis, K,,, is the curvature along the Y A axis, and ZA is the outwardly pointing normal (see Figure 2). x A , y A , and zA define an orthogonal coordinate frame, affixed to the finger, which we refer to as oA.The grasped object is likewise modeled, using the subscript \u201cB\u201d (see also [12]) The angle I+Y specifies the orientation about the common normal of one 2Z,4 i- KUA X i f K,,, y ; = 0 (7) 1368 body with respect to the other. In Figure 2b, this angle is defined such that a positive (counterclockwise) rotation of X , about zA through yaligns the axes X A and xB. In general, II# 0 (i.e. the pFinciple axes of curvature are not aligned). In [5,9], we show that following relationship applies: where the contact stiffness matrix, K,, is the 6x6 matrix given by Equation (9) below: F,,L,(L, + c a ) ' t B + k , ~ oZxf -F,,L,(L, + t , ) ' ~ oZxt AF/A = -K, AX^,, (8) Oh* kll orx> 0 (MOL, -F ,d ) (L , + L B ) ' L B AF,\" (F , , ,A-4LA)(LA + c B r ' A I FE A 0 O M ko F,, is the applied normal force, FtXO and Ftyo are the Cartesian components of the applied tangential (frictional) force (in the xA and yA direction, respectively), and M O is the applied torsional moment"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000497_a:1008966218715-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000497_a:1008966218715-Figure1-1.png",
+ "caption": "Figure 1. Scanning range of laser range finder.",
+ "texts": [
+ " The map of the whole environment is essentially a collection of the obstacle regions characterized by their own stochastic parameters. This paper is organized as follows. Section 2 introduces the concept of clustered region and describes the data clustering procedure. Section 3 introduces the concept of obstacle region and presents a map building procedure using the obstacle regions. Experimental results are discussed in Section 4, and conclusions and comments on future research are made in Section 5. Figure 1 shows the scanning range of the laser range finder that covers about 270\u25e6 of the front side. The center position pc of the mobile robot is represented as (xc, yc) in terms of the world coordinate frame. The incoming data are numbered in the counterclockwise direction and l j , j = 0, 1, . . . 270, are the distance values from the center position of the laser range finder to the objects. The object position p j = (x j , y j ) is determined from the measured distance l j as follows: p j = (x j , y j ) = ( xc + l j cos ( ( j \u2212 45)\u03c0 180 + \u03b8c\u2212 \u03c0 2 ) \u2212 ld cos \u03b8c, yc+ l j sin ( ( j \u2212 45)\u03c0 180 + \u03b8c\u2212 \u03c0 2 ) \u2212 ld sin \u03b8c ) = (xc, yc) + ( l j cos ( ( j \u2212 45)\u03c0 180 + \u03b8c \u2212 \u03c0 2 ) \u2212 ld cos \u03b8c, l j sin ( ( j \u2212 45)\u03c0 180 + \u03b8c \u2212 \u03c0 2 )\u2212 ld sin \u03b8c )) = pc + l j where ld is the distance from the center of the laser scanner to that of the mobile robot and \u03b8c is the angle of the mobile robot measured counterclockwise from the positive x-axis"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002923_acc.2005.1470620-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002923_acc.2005.1470620-Figure8-1.png",
+ "caption": "Fig. 8. ECAV velocities when the ECAV imposes a restriction on the phantom\u2019s velocity annulus.",
+ "texts": [
+ " For any number of ECAVs, for all realistic initial conditions there will always be a feasible velocity sector for the phantom which would guarantee feasible trajectories for the ECAVs. The algorithm would then pick a velocity for the phantom from its feasible velocity sector which would make it travel towards the final waypoint in minimum time. If any one of the ECAV\u2019s states is such that it imposes a restriction on the phantom\u2019s movement through the sufficient condition, it is interesting to note that no matter what velocity heading is picked for the phantom, the ECAV can travel only in a direction that would relax the restriction placed by it at the phantom. Fig.8 illustrates this point. Here 0 max 0 maxr V R W , this implies for all cr It can be then shown that, Hence in the absence of additional constraints, any restriction placed by ECAVs on the velocity annulus of the phantom only relaxes with travel time and ultimately would cease to apply. It can be shown that the condition for an ECAV to be collinear with the phantom and the radar for all time and not just at the end of time steps of the algorithm is, 0 maxmin max 0 min r WW V R V (13) The initial conditions that all ECAVs should satisfy to guarantee a straight line path for the phantom from its first waypoint to the targeted waypoint is, 0, max 0, min i i r W R V (14) where i indexes the ECAVs. When the ECAVs are free to pick one of two velocity headings as shown in the right hand diagram of Fig.8, the algorithm picks the velocity that would take the ECAV to the range given in (13). The fact that the ECAVs will, for most times, have two velocities to pick from, allows the algorithm to easily implement a lower bound on the range of the ECAVs from their respective radars. The algorithm was coded in MATLAB and Fig. 9 gives the simulation results for the case of four ECAVs when the initial conditions are such that initially restrictions are imposed on the annular velocity sector of the phantom"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000385_s0045-7949(98)00165-5-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000385_s0045-7949(98)00165-5-Figure1-1.png",
+ "caption": "Fig. 1. Triangular plate element with layer-wise approximation.",
+ "texts": [
+ " The element can be considered an extension of the linear/ quadratic Reissner\u00b1Mindlin plate element based in an assumed shear strain approach formulated by Zienkiewicz et al. [4], Taylor and Papadopoulus [5] and On\u00c4 ate et al. [6\u00b18]. The inplane element displacements are interpolated linearly inside every layer and they are eliminated during the global assembly by means of a condensation technique. In the following sections details of the element formulation are presented, together with some examples of applications to static, dynamic and instability analysis of laminated composite plates and shells. Fig. 1 shows the geometry of the element. It is worth noting that the laminate is discretized into n analysis layers and n + 1 interfaces. The analysis layers can or cannot coincide with the real material layers. The horizontal displacements (in plane displacements) for the kth layer are interpolated as 0045-7949/99/$ - see front matter # 1999 Published by Elsevier Science Ltd. All rights reserved. PII: S0045-7949(98 )00165-5 u v n o X3 i 1 Ni x; Z Nk z uki vki Nk 1 z uk 1i vk 1i ( )24 35 X6 i 4 Ni x; Z ei\u00ff3 Nk z Dukti Nk 1 z Duk 1ti h i 2 where Dukti (i = 4, 5, 6) are the nodal displacement increments at the element mid-sides for the kth interface in the direction of the unit vectors ei \u00ff 3 (Fig. 1). The normal displacement is assumed to be constant across the thickness and it is interpolated in terms of the corner values in the standard fashion as w X3 i 1 Ni x; Z wi 3 In Eqs. (2) and (3) Ni x; Z Li i 1; 2; 3 N4 x; Z 4L1L2; N5 x; Z 4L2L3; N6 x; Z 4L1L3 4 where Li are the linear shape functions for the three node triangle [9] and Nk z 1\u00ff z 2 ; Nk 1 z 1 z 2 5 Eqs. (2) and (3) imply a hierarchical quadratic interpolation for the in-plane displacements u and v in the plane of every layer and a linear interpolation for w",
+ " The displacements u 0, v 0 in the element plane corresponding to the kth layer are interpolated by [1\u00b13]: u 0 v 0 X3 i 1 Ni x; Z u 0oi v 0oi Nk z u 0ki v 0ki Nk 1 z u 0k 1i v 0k 1i ( )24 35 X6 i 4 Ni x; Z ei\u00ff3 Nk z Dukti Nk 1 z Duk 1ti h i 16 where u 0oi v 0 oi n o are constant (rigid-body) in-plane displace- ments across the thickness of the laminate, u 0ki v 0k i n o are the in-plane displacements which are variable over the thickness and Dukti are the in-plane displacement increments in the midside nodes of the triangle in the directions de\u00aened by the tangent vectors ei \u00ff 3 (Fig. 1). The normal displacement w 0 is assumed to be constant throughout the thickness. Following this hypothesis it is possible to write w 0 X3 i 1 Ni x; Z w 0i 17 In Eqs. (16) and (17) the shape functions are the same that those given by Eqs. (4) and (5). Eqs. (16) and (17) de\u00aene a quadratic interpolation over every interface for the in-plane displacements u 0 and v 0 and a linear interpolation for the displacement w 0. The local strains for the kth layer are written e 0b @u 0 @x 0 ; @v 0 @y 0 ; @u 0 @y 0 @v 0 @x 0 \" #T Bba 0 18 e 0s @w 0 @x 0 @u 0 @z 0 ; @w 0 @y 0 @v 0 @z 0 \" #T Bsa 0 19 where e 0b are the local strains accounting for membrane and bending e ects and e 0s are the transverse shear strains"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000845_s0967-0661(00)00032-0-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000845_s0967-0661(00)00032-0-Figure2-1.png",
+ "caption": "Fig. 2. Flexible body structure in the pitch plane.",
+ "texts": [
+ "qP 0 , (7) where a, b represent angle of attack and side slip angles, respectively, >b , Za are aerodynamic force coe$cients, M q , Ma , N r , Nb are aerodynamic moment coe$cients, >d , Zd are control force coe$cients, Md , Nd are control moment coe$cients, d y , d z are canard de#ections in the pitch and yaw direction, respectively. If P 0 is equal to zero, the dynamics of the pitch and yaw axis is decoupled completely and the transfer function between the pitch angular velocity and the canard \"n de#ection can be written as q(s) d z (s) \" Mds#(ZdMa!ZaMd ) s2!(Za#M q )s!(Ma!ZaMq ) (8) 2.3.2. Bending vibration dynamics The gyroscope in the rocket attitude control loop measures not only the rigid body motion but also the bending vibration mode due to the #exible body e!ect as in Fig. 2, which can be expressed mathematically as m(l ) L2m(l, t) Lt2 # L2 Ll2 CEI(l ) L2m(l, t) Ll2 D\"Fd(l, t), (9) where m is the mass per rocket unit length, m the rocket de#ection due to bending moment, E the Young's modulus, I the area moment of inertia about neutral axis, Fd the external force of bending vibration. Assume the solution of (9) can be separated in time and space and of the form (Meirovitch, 1967) m(l, t)\" = + i/1 u i (l )g i (t), (10) where u i and g i are the eigenfunction and normal coordinate of ith bending mode"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001799_s0168-874x(02)00056-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001799_s0168-874x(02)00056-2-Figure1-1.png",
+ "caption": "Fig. 1. Principle illustration of a rotary forging process: 1\u2014rocker; 2\u2014billet; 3\u2014ram; 4\u2014oil vat.",
+ "texts": [
+ " The pressure distributions of the contact surface along the radial and tangential directions and e9ects of rotary forging parameters on deformation characteristics are given. ? 2002 Elsevier Science B.V. All rights reserved. Keywords: Metal forming; Finite element method; Rotary forging; Ring workpiece A rotary forging process is a kind of metal forming method where a conic upper die, whose axis is deviated an angle from the axis of machine, forges a billet continuously and partially to \"nish the whole deformation, as shown in Fig. 1. To date, much of the research work on rotary forging has been conducted in many countries, such as Britain, Japan, China, Germany, America, Poland and the former Soviet Union. These works concentrated mainly on calculating and verifying the energy parameters and measuring the pressure distributions at the contact area. However, due to the di9erent experimental methods and conditions used by researchers, the results obtained could not show a general agreement. At the same time, because of the complexity of kinematics relationship between \u2217 Corresponding author"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001183_s0020-7683(00)00010-x-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001183_s0020-7683(00)00010-x-Figure10-1.png",
+ "caption": "Fig. 10. Dimensions of circular bearings.",
+ "texts": [
+ " (48) is dmax h F0 P 2 jg1j g2 2 g2 3 q : 63 The maximum height reductions calculated from the above equation shows that, subjected to the same compressive force and the same amplitude of horizontal displacement, columns of a smaller rigidity ratio q or a smaller loss factor g have a higher height reduction. Two groups of isolation bearings were used in the cyclic shear tests. One group of bearings were made of high-damping rubber and the other group of bearings were made of normal rubber, which has a lower damping value. The dimensions for the two groups of bearings were identical. Each group had two shapes: circular and square. The circular bearings, whose dimensions are shown in Fig. 10, have 20 thin rubber layers with thickness t 10 mm and 19 steel shims which are 2 mm thick. The total rubber thickness is tr 200 mm and the height of the bearing excluding the end plates is h 238 mm. The shim diameter is d 280 mm and there is 10 mm of cover for a total diameter of 300 mm. The square bearings, whose dimensions are shown in Fig. 11, have the same number of rubber layers and steel shims as do the circular bearings, but the thickness of the rubber layers is t 6 mm. The total rubber thickness is tr 120 mm and the height of the bearing excluding the end plates is h 158 mm"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000423_1.2834110-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000423_1.2834110-Figure1-1.png",
+ "caption": "Fig. 1 Journal bearing cross-section with relevant nomenclature. The journal (inner member) is rotating clockwise and the bearing (outer member) is stationary.",
+ "texts": [
+ " Furthermore, microfabrication concerns impede or exclude ad ditional means of stabilization, such as herringbone grooves (Fleming and Hamrock, 1974), tilting pads (Lund, 1968), and mid-bearing hydrostatic jacking ports (Powell, 1964). This work was undertaken to provide the tools and understand ing necessary to produce stable gas journal bearings for high speed microturbomachines. To do this, a flexible simulation code was written to allow many design options and manufacturing defects, as well as the interplay between them, to be examined. Bearing Nomenclature and Parameterization The geometry and nomenclature used in this work are shown in Fig. 1. In this article, W is the applied load, R is the bearing radius, r is the journal radius, and their difference, the clearance, is denoted by c. The attitude angle, <\u0302 , is the angle between the applied load and a line connecting the journal and bearing cen ters. The excursion of the journal center from the bearing center, denoted by e, is normalized by c and expressed as an \"eccen tricity ratio,\" e, so e = 0 and e = 1 represent fully-centered Contributed by the Tribology Division of THE AMERICAN SOCIETY OF IMECHANICAL ENGINEERS and presented at the Joint ASME/STLE Tribology Conference, Toronto, Canada, October 25-29, 1998",
+ " Toward this end, following Ausman (1961), $ is defined as the pressure, p, times the channel height h. The Reynolds equation for a compressible, isothermal ideal gas in a journal bearing with perfect axial alignment (i.e., discarding terms involving changes of passage height in the axial direction) may then be expressed as: /!* - ^ ' \u2022 d^h ^ dhd^ , - * + h de do de) (6) for a bearing-centered, non-rotating coordinate system. The ^- coordinate refers to the axial direction (perpendicular to the page in Fig. 1) and is normalized by r. Position in the circumfer ential direction is fixed by 0, which is measured counter-clock wise from a vertical line and is zero at the top of the bearing. This equation differs from that employed by Cheng and Pan only in the absence of a grid rotation term. It is very convenient for a spectral method because it is devoid of cross-derivatives and, in total, only four spatial derivatives must be computed. Just two forward transforms and four backward transforms are therefore required per timestep"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001191_0005-1098(93)90125-d-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001191_0005-1098(93)90125-d-Figure2-1.png",
+ "caption": "FIG. 2. Top view and kinematic parameters of a mobile robot.",
+ "texts": [
+ " Its kinematics and dynamics can be modeled based on the necessary assumption that the wheels are ideally rolling. The conditions to achieve rolling without slipping and skidding are presented. 2.1. Kinematic modeling Although the development of Alexander and Maddocks (1989) is based on the assumption of planar motion their analysis holds for the case of general terrains with the additional assumption that the curvature of the floor is such that sufficient contact of the wheels is guaranteed. Consider the top view of a mobile robot (Fig. 2) moving along a trajectory described in a parametric form by r(s) where s is the parametrization variable. The world coordinate frame (Px, Py, Pz) with unit vectors (i, j, k) is fixed at O. The body coordinate frame (pff, p~, p~) is attached to the body at point B and moves along r(s). The motion of the robot is described by r(s) and the orientation angle function O(s), defined as the angle between px and pff. The instant translational velocity of the robot with respect to the world coordinate frame is ~(t) and its rotational velocity is tb ( t )= to(t)/~",
+ " (1986). A strategy for obstacle avoidance and its applications to multi-robot systems. In Proc. of the 1988 IEEE Int. Conf. on Robotics and Automation, pp. 1224-1229. Wu, C. and C. Jou (1988). Design of a controlled spatial curve trajectory for robot manipulators. In Proc. of the 27th Conf. on Decision and Control, pp. 161-166. APPENDIX A: ROBOT INVERSE DYNAMICS If it is known that the object has, at instant t, translational velocity, v(t), orientation angle O and rotational velocity to(t) = O(t) (Fig. 2). Then the instantaneous angular velocity and steering angle of the wheel i, are (Alexander and Maddocks 0989)): b, = 1 r X ~/Iv(t) 2 + Ixffl 2 (to(t)) 2 - 2 \u00d7 Io(t)l txffl to(t) cos (fl - ai - O(s(t))), (A.1) & = t - l / v(t)l sin )6 - Ix~l to(t) sin (ow are obtained by replacing the transformation matrices in Eqs. (18) and (19), respectively, by their derivatives utilizing Eq. (12). Note that vk m and \\Jiki m are functions of angular velocity components as well as displacements. 5. Mass Center Velocities and Accelerations The position vector from the fixed reference axis w\u00b0 in R to the mass center of the ith element in Bk is given by (with the notation of Fig. 2) (26) (17) where the summations are carried for the bodies along the path from Bk to R and where dl = 0. D ow nl oa de d by P U R D U E U N IV E R SI T Y o n A pr il 13 , 2 01 5 | h ttp :// ar c. ai aa .o rg | D O I: 1 0. 25 14 /3 .2 04 88 NOV.-DEC. 1989 DYNAMICS OF FLEXIBLE TREELIKE STRUCTURES 833 By differentiation, the mass center velocity of the element is obtained as H(k) H(k) H(k)nP Z where s = Yq(k) and p = T(s). The ds can be written as (27) (28) where qs is the vector in the undeformed state"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002270_robot.2001.933127-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002270_robot.2001.933127-Figure1-1.png",
+ "caption": "Figure 1: Three-link 3R planar robot manipulator. This configuration is known as SCARA. The angles { 0 1 , 0 2 , 0 3 } are measured counterclockwise. {z, y} is the location of the third joint.",
+ "texts": [],
+ "surrounding_texts": [
+ "Lemma 3.2. The vector field V zs decoupling for the mechanical system ( 3 ) zf and only zf\nfol- d l 1 5 b 5 n - rn.\nProof. Consider a curve q ( t ) on Q such that i ( t ) = S( t )V(q ( t ) ) . W e compute the quantityoya using two properties of the covariant derivative; see [14]. Since 0x5' is a. differentiation in the second argument, one call prove that\noyfj = vq ( S V ( q ) ) = SV(q) + so$+$ Furthermore, since VxY is linear in the first argument, oiie can prove that\nNexl,, the mrve q ( t ) is a kinematic motion and I/ is a decoupling vector field if the constraints (8) are satisfied. These can be written as:\nfor all 1 5 b 5 n - 7n. Note that ( ( V , xb)) and ((VI/\\[, Sb)) are equivalent to a(.) and b(s) in equatioii ( t ) , respectively. Since s is an arbitrary time scaling and qo is an arbitrary point, V and V v V niiist separately have a vanishing inner product with -7jb. The sillne argument also shows the other implication U\nR.oughly speaking, equation (11) encodes the requiremeiit tlmt motion along V at constant speed be feasible. Equation (10) requires the system to be able to speed u p and slow down the motion along V .\nNote h a t scalar multiples of decoupling vector fields a.re a.gain decoupling, but linear combinations ma.y not be decoupling. There are mechanical control systems for which no decoupling vector fields can be found. The maximum number of linearly independent decoupling vector fields is m..\nA.s described in the introduction, decoupling vector fields reduce the complexit>y of motion planning problems by turning a dynamic problem in to a driftless kinema.tic one. Accordingly, it is of interest to define the class of systems for which this approach a.mlies.\nDefinition 3.3 (Kinematic con trollability). The m.echanica1 system ( 3 ) is kinematically controllable i f every point in the configuration space Q i s reachable via a sequence of kinematic mmtions. The system ( 3 ) i s locally kinematically controllable i f fo,r any q E Q and any neighborhood U, of q , the set of reachable configurations fr0m.q by kinematic motions remaining in U, contains q in its interior.\nObviously, the main difficulty is that there simply might not be enough decoupling fields for controllability. A sufficient test for local kinematic'controllability is given below. We assume the reader to be familiar with the Lie algebra rank condition for local controllability; see [15]. Lemma 3.4. The system ( 3 ) i s locally kinematicully controllable if there exist p 5 m vector fields {VI , . . . , VP} such that\n(ai) Lie{Vl,. . . , I+} has rank 11 at all q E R\"\nProof, Property ti) ensures that the vector fields V, are decoupling. Property ( i i ) ensures the local con- ~- trollability of the driftless k i k\nP 4 = C K ( ( I ) w c\nC = l\n( W l , . . . ,,uJp) E ((*1,0,. . . (0,. . , o , f\niatic system (2)\nO), (0, *l, 0,. . . , O ) , . . . , )>\nand therefore every point in the configuration space is reachable. In the presence of obstacles, a collisionfree path exists between any two points in an open U connected set of the configuration space.\nFinally, we coinpare our novel characterization of controllability with the notion of small time local configura.tion controllability (STLCC) introduced by Lewis and Murray [lo]. Kinematic controllability implies STLCC, while the opposite is not, true. In other words, kinematic controllability is only one way in which a n1echanica.l system can be STLCC. Kinematic controllability is neither implied by, nor implies, small time local con trollability (STLC).\n3.1 Computing decoupling vector fields\nMotiva.ted by the sufficient, test for local kinematic controllability in Lemma 3.4, we investigate how to look for decounling vector fields V . Intuition about",
+ "the behavior of the system is helpful, but a direct algorithm would simplify the task. According to Lemma 3.2, t WO conditions need to be satisfied. To automatically satisfy the first one while losing no generality, we write\nm\nV(q) = C ha ( q ) Y a ( q ) ,\nwhere h(q) = ( h l ( q ) , . . . , / ~ \u201c ( q ) ) ~ are m arbitrary functions on Q. From [14], we recall the identity V x ( h Y ) = h(VxY) + (.Cxh)Y, where Cxh is the Lie derivative of h along X . We compute\na=l\nm m\nvVv = ( h a h b o y a y b + h a ( ~ , h b ) yb), a=l b=l\nso that the vector field V is decoupling if (iii) Numerous vehicle models including the idealized planar hovercraft (planar body with two forces\n0 = ((xc, Vy,yb))(q) (12) away from center of mass) and a rigid body in SE(3) with three thrusters away from the center of mass. The dynamics of these systems are indefor 5 5 - m. Equation (la) is pendent of the configuration, allowing simplified in the unknown functions i h l , . . . > h m ) uration dependent; no general solution methodology appears to be available. Nonetheless it is possible to 4.1 Three link planar robot manipulator find decoupling vector fields in a number of useful examples by relying on insight into the behavior of the system. we will see in section 4.2, Equation (12)\nm m\na=l b = l\ntests for decoupling vector fields (Section 4.2).\nwith a passive joint\nW e consider a three joint robot manipulator mwing\nordinates will be suited to different tasks: the set {@I, &,e,} consists of the absolute angles (measured 4 Examples and extensions counterclockwise) of the three links with respect to\nNumerous systems fit the requiremen ts of Lemma3.4, the horizontal axis, the set {01, ~ Z I 7 3 ) m ~ ~ ~ e s the allowing the decoupling of trajectory planning, E ; ~ - relative angles a t the second and third joint, and amples include: {z, y, 0 3 ) measures the absolute location of the third\njoint and the absolute angle of the third link.\nActuator configuration (0,1,1;)\nsimplifies considerably for certain vehicle models, in a horizontal Plane (see Fig11re \u20181. Different\n(i) All systems subject to nonholonomic or conservation law constraints for which kinematic equations of motion can be written. These systems W e rely on the coordinate system { Q1, yz, y 3 } , Acare described for example in [161 as cordingly, the input co-vector fields Fl, F2, and the locomotion systems\u201d and in [I13 as \u201ckinematic mechanical systems.\u201d Examples include the upright rolling penny and a 3R planar robot arm\n(0 ,1 ,1) ) .\njoint (actuator configuration (1 ,1 ,0) ) . This was the original motivating example in [7], and it is worked out below in full detail. For the actuator configuration (1 ,0 , l ) , we provide one decoupling vector field, but we do not answer the kinematic In other words, the components of the inertia matrix controllability question. W e present all the 3R are independent of 01 and depend on { Q , r3) in a planar robot configurations in Section 4.1. specific manner.\nannihilator vector field x are\nd F1 = dr2 , F2 = dr3, X = ~\nIt is a straightforward computation to see that the\nwith a passive first joint (actuator configuration 801 \u2018\n(ii) A 3R planar robot arm with a passive third inertia matrix A4 has the following structure:\nMlZ(rZ,r3) M22(r3) M23(r3) . (13) M I I ( ~ z > ~ ~ ) MlZ(rZ,r3) M13(rZ,r3) 1 [ M13 (TZ, r3) M32 (T3) M33",
+ "Leiiiiiia 4.1. Coizszder the maizipulator wtth a passive f irs t joiizt. The system as locally kzizeniatacally coiztrollnble m i d two decouplang vector fields are joint to the center of mass of the third link. kinetic energy of the third link is The\n1 1 2 - ( I 3 + m31:)i ; + p ( i 2 + y2)\nVI = Y1 = AKIF1 = M-ldl.2 + m3/3&(~ cos ~3 - j. sin 03).\nV, = Y i = M-'FZ = M-ldr3 . The input co-vector fields F1, F2, and the annihilator vector field X can be written as Proof. By construction, we have\nd dB3 ' F1 = dx, F2 d y , X = - 0 = ((X > Vl)) = ((X, VZ)),\nancl it is easy to see that\n[Vl, v21 $! span(V1, VZ)\nLemma 4.2. Consider the manipulator with a passive third joint. The system ' i s locally kinenzatically controllable, and two decoupling vector fields are\nd d VI =cos&-- + s i n & _\nV2 = sin&- - cos6'3- + --, Next, we show that 0 = ( ( X , Ov,K)) via Ma.thema.tica.TM. The following code illustrates the d X dY computations required to prove that the conditions in d d l a Lemma. 3.2 are satisfied, so that {VI, V 2 ) are indeed ax a y A d 0 3 decoupling.\n(** Mathematica code f o r SCARA 011.\nNeeds [\"MechSys \"'1 ; q = C t h l , r 2 , r 3 ) ;\nwhere X = ( I 3 + ni,3li)/m313. These motions are translation along the third link and rotation of the third link about its center of pel-cussion, respectively.\nProof. It is easy to compute that\n** ** Configuration, inertia, and connection **)\nM = {{Mll[r2,r3], M12[r2,r31, M13[r2,r3]), (M12 [r2 , r3 ] , M22 [r31 , M23 Cr3l 1 , CM13 [ r2 , r3 ] , M23 [I-31 , M33 11 ; InvM = InverseCMl ; n a b l a = LeviCivitaCM, q l ;\n(** i npu t one-forms and a n n i h i l a t o r **) Fl={O, 1 , O ) ; F2=(O , 0 , 1 ) ; X={l, 0,O);\n(** decoup l ing v e c t o r f i e l d s and ** ** t h e i r c o v a r i a n t d e r i v a t i v e s **) V 1 = InvM . F1; V2 = InvM . F2; V 1 1 = CovariantDerCVl, V1, n a b l a , q l ; V22 = CovariantDerrV2, V2, n a b l a , q l ;\n(** t h e s e q u a n t i t i e s v a n i s h **) Simplify[{Vl.M.X, Vll.M.X, V2.M.X, V22.M.X)I\n0\nNext, we show that 0 = ( ( X , Ov,K)) via MathematicaTM. To streamline the computations, we redefine the terms (M11, M12, M22) to account for the term i m 3 ( k a + y 2 ) , and we scale them by a factor m3l3.\n** (** Mathematica code f o r SCARA 110. ** c o n f i g u r a t i o n , i n e r t i a , and c o n n e c t i o n **) Needs [\"MechSys' \"1 ; q = (x , y , t h 3 3 ; fl = ( (Ml l [x ,y l , M12Cx,yl, -S in[ th31) ,\n{M12[x,yl, M 2 2 h , y l , CosCth31 1, {-Sin[th3] , Cos Cth31, lambda 1) ;\nn a b l a = Simpl i fy [ LeviCivitaCM, 411;\n(** i n p u t one-forms and a n n i h i l a t o r **) F1={1 ,O , O ) ; F2={O, 1 ,Ol; X={O , 0 , 1 ) ;\nActuator configuration ( l , l , O ) (** decoup l ing v e c t o r f i e l d s and **\nv1 = {Cos[th3], Sin[th3], o); W e rely on the coordinate system {x, Y, Q 3 > . The kinetic energy of the first two links can be written as ** t he i r covariant derivatives **)\nV2 = {Sin[ th3] , -Cos[th31, l / l ambda 1; &fll(X, Y) MlZ(X, Y) , V 1 1 = Covar ian tDer[Vl , V1, n a b l a , q l ;\nl % Z ( X , Y ) MZZCX,Y) Y V22 = CovariantDer[V2, V2, n a b l a , q l ; 1 [\"I Let 7 j x 3 , 13 denote the mass and moment of inertia of (** t h e s e q u a n t i t i e s v a n i s h **) the third lillk; let l3 be the distance from the third Simplify[{Vl.M.X, Vll.M.X, V2.M.X, V22.M.XIl"
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0001752_jsvi.1997.1511-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001752_jsvi.1997.1511-Figure1-1.png",
+ "caption": "Figure 1. The intrinsic coordinate system.",
+ "texts": [
+ " Since all energy terms concerned are fully derived, the dynamic equation of a general conical spring turns out to be Gs J(r12y/1s2 + r'1y/1s)= (rIs,m + r3ms )12y/1t2, (5) where r'= 1r/1s. If the radius change r' is zero, i.e., the cylindrical spring, the differential equation can be simplified into the well known undamped wave equation: V2 w 12y/1t2 = 12y/1s2, (6) where V2 w =Gs d2/r(8r2 + d2) and r represent the spring wire density. 3. SPRING RATE FOR A GENERAL HELICAL SPRING In order to derive the spring constant of the general helical spring with variable helix radius and variable pitch angle, a co-ordinate system, as shown in Figure 1, is defined. A general helix parametrized by arc length can be expressed as X (s)= r(s) cos u(s)i + r(s) sin u(s)j + h(s)k , (7) where mean radius r, polar angle u, and local helix height h, are all functions of helical length s. Then the tangent of the parametric curve is expressed as the derivative with respect to the helical length s: T (s)=X '(s)= (r' cos u\u2212 u'r sin u)i +(r' sin u+ u'r cos u)j + h'k . (8) The unit tangent is t =T (s)/=T (s) ==(1/W) [(r' cos u\u2212 u'r sin u)i +(r' sin u+ u'r cos u)j + h'k ], (9) where W=zr'2 + r2u'2 + h'2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003246_iemdc.2005.195977-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003246_iemdc.2005.195977-Figure4-1.png",
+ "caption": "Fig. 4. Instantaneous frequency of simulated current signal with apparition of load torque oscillation (magnetically coupled electric circuits)",
+ "texts": [
+ " 2 shows the result from the model based on magnetically coupled electric circuits, Fig. 3 from the space phasor simulation. The theoretically calculated interference structure at fs\u00b1fc/2 is clearly visible in both time-frequency distributions. Only slight differences in amplitude exist between the two simulations. Further simulations at higher and lower load levels always show the same effects on the PWD. The calculation of the stator current IF for the previous signal leads to the result displayed in Fig. 4. Small oscillations are already present in the healthy current IF. The load torque oscillation starting at 0.6 s leads to significant IF oscillations. As the simulations agree with the theory and the experimental results, only the last will be commented in details. As a conclusion, it can be stated that the simple machine model is well suited to correctly represent the effect of the load torque oscillation and that there is therefore no need in this case for a time intensive and detailed simulation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003117_bf00618738-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003117_bf00618738-Figure1-1.png",
+ "caption": "Fig. 1. A schematic diagram of the undivided flow cell A.",
+ "texts": [
+ " The two types of cell (A and B) that were used are shown schematically in Figs. 1 and 2. Cell A was made of four polyethylene blocks machined to have a cylindrical bore (2.5 cm diameter). The dimensions of the cell were 7.6 x 7.6 x 10 cm 3. The electrical connections were a lead rod and a platinum wire for the cathode and anode, respectively; a Luggin capillary, made of a fine vinyl tubing, was connected to the saturated calomel electrode. The cathode had a total surface area of 30 cm 2 and the graphite anode is shown as its actual size in Fig. 1. Cell B was made of a glass tube (5 cm diameter and 10 cm long). Glass beads were placed below the cathode to ensure a uniform current distribution through the packed-bed electrodes. Glass beads were also placed above the anode to decrease the total void space in the cell. Perforated vinyl discs were inserted between the electrodes and glass beads, and a ring-shaped Teflon spacer (1 cm thick) was placed between the anode and cathode. Electrical contacts were made from the top and bottom of the cell (Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001679_(sici)1521-4109(20000301)12:5<343::aid-elan343>3.0.co;2-e-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001679_(sici)1521-4109(20000301)12:5<343::aid-elan343>3.0.co;2-e-Figure9-1.png",
+ "caption": "Fig. 9. Glucose calibration plots at 950 mV after subtracting the blank: a) amperometric, b) CV peak heights at 5 mV=s using the Au-RSH-GOxPVP electrode (8 days old).",
+ "texts": [
+ " This is also the reason for the slow scan rates used in the CV scans, as noted previously by Cass et al. [16] for the ferrocene mediator. The calibrations vary in slope and sensitivity according to the sensor membrane composition used. The results of CV scans for increasing glucose concentrations as shown in Figure 3 indicate the increase in the anodic peak together with the disappearance of the cathodic peak as the catalytic anodic current increases with increasing glucose concentration. A plot of peak height against glucose concentration shown in Figure 9 shows linearity up to approximately 15 mM glucose. The calibration from the amperometric mode of operation is also shown for comparison in Figure 9. There is some difference due to the shift in peak voltage as the glucose concentration is increased. The amperometric precision of replicate glucose measurements and rate of response was also measured. Eight replicates of a 5 mM glucose solution gave an RSD of 2.1 % for a mean current value of 1.27 mA. The electrode response reached 95 % of steady state within approximately 50 s and stayed constant for up to 3 min before the electrode was reimmersed in the blank solution. The blank current reading drifted by approximately 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003024_1.2103093-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003024_1.2103093-Figure3-1.png",
+ "caption": "Fig. 3 Simple brush seal used in the",
+ "texts": [
+ "url=/data/journals/jotuei/28726/ on 05/06/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use numbers Downloaded From: http://turbomachinery.asmedigitalcollection.asme.org/pdfaccess.ashx generator, it is possible to then obtain a new grid to use in the next CFD simulation. The procedure described above should be continued until convergence in the deformation is found. In order to test the iterative procedure, a simple brush seal configuration, was set up including a row of just five bristles, as shown in Fig. 3. In this test case, both the mechanical and fluid dynamics models assumed periodicity in the circumferential direction. The iterative procedure is described and illustrated below using this simple example. Further results for a simple geometry and a real seal geometry are then given in Sec. 3. 2.2 Mechanical Model. SUBSIS an acronym of Surrey University brush seal iterative simulator was used in this study. This is an iterative code developed to predict the bending behavior of bristles in a brush seal",
+ " Analogous procedures are also possible for other commercial mesh generators. To keep this meshing procedure completely automatic, the following approach was adopted: \u2022 Definition of a volume containing the finer and unstructured part of the mesh, but large enough to contain the deflected bristles. \u2022 Bristles\u2019 radius reduction to avoid bristle intersections as explained in Sec. 2.3. 3.1 Simplified Geometry. The iterative coupling procedure was first used to predict the 3D bending behavior of bristles in the simple brush seal shown in Fig. 3. The parameters employed in this work are as summarized in Table 1 unless otherwise stated. The Young\u2019s modulus used is for a cobalt-based alloy known as Haynes-25 see Ref. 14 . Incompressible flow and an axially directed inflow is assumed in this simplified model. Each iterative calculation in the mechanical model has been continued until the displacement residual was much smaller than the deflection. The axial aerodynamic forces per unit length acting on each of the five bristles and the pressure field on the periodic plane of the incompressible CFD solution are shown in Figs"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000999_978-3-7091-2626-4_4-Figure7.2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000999_978-3-7091-2626-4_4-Figure7.2-1.png",
+ "caption": "Figure 7.2: Square plate with a central circular hole",
+ "texts": [
+ " The value for the load factor (3 obtained by the reduced basis technique was (3 = 18.61. In Fig. 7.1b the iteration history for the classical SQP-algorithm and the special SQP-algorithm is compared. Obviously, the convergence behavior of the latter is superior. Shake-down Analysis 229 7.2 Square plate with a central circular hole A square plate with a central circular hole is considered. The length of the plate is L and the ratio between the diameter of the hole and the length of the plate is 0.2. The system is subjected to the biaxial uniform loads PI and p2 (see Figure 7.2). Both can vary independently of each other between zero and certain maximum magnitudes p1 and p2 \u2022 The load domains are defined by 0 ~\u00b7 PI ~ f3 \"'11 O\"o = PI , 0 ~ P2 ~ /3/2 O\"o = ih , 0 ~ /I < 1 0 ~ /2 < 1' where O\"o is the initial yield stress of the employed material and {3 is the shake-down load factor. Suitable choices of /I and 12 enable us to investigate arbitrary load variation domains with different ratios of the load limit PI to P2\u00b7 The shake-down behavior of this system consisting of elastic, perfectly plastic ma terial firstly was investigated numerically by BELYTSCHKO [3] by use of 26 elements"
+ ],
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+ "image_filename": "designv11_6_0003049_b:tril.0000044509.82345.16-Figure11-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003049_b:tril.0000044509.82345.16-Figure11-1.png",
+ "caption": "Figure 11. Maps of calculated friction coefficient calculated assuming a Hertz pressure distribution with centre of pressure at three different grid locations. Test conditions are U \u00bc 1.13 m/s, W \u00bc 50 N, slide roll ratio \u00bc )1.0 (ball faster). Contact inlet on left.",
+ "texts": [
+ " In this work, the contact centre was found iteratively, by guessing its location to lie at various positions within the contact and, based on this, evaluating the pressure map and thus, from the ratio of the shear stress to the pressure at each position, the corresponding friction-coefficient map. It was clear from the shape of this map when the correct contact centre had been located, since only then did the friction map fail to fall sharply to zero at the inlet or exit while being reasonably symmetrical transverse to the sliding direction. Figure 11 shows three computed friction-coefficient maps based in the contact centre being in three different locations, at i \u00bc 10.8, 12.8 and 14.8 grid spacings respectively from the left-hand edge of the region mapped. (The friction coefficient outside of the Hertz contact region has been set to zero). Based on these maps, the contact centre was taken to be at the i \u00bc 12.8, j \u00bc 16.5 grid position in this case. Using this approach, the temperature and pressure at each grid point and each slide-roll ratio studied were determined"
+ ],
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+ "image_filename": "designv11_6_0000549_0890-6955(95)00099-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000549_0890-6955(95)00099-2-Figure1-1.png",
+ "caption": "Fig. 1. The domain and the finite element mesh.",
+ "texts": [],
+ "surrounding_texts": [
+ "Rolling can be considered as one of the most important processes in industry, and is at the same time one of the oldest metal-working processes. Numerous investigations, both analytical and experimental, have been carried on the rolling process [1-19]. In view of the complexity of the process, these methods make use of several assumptions. A slab method for flat rolling proposed by Orowan [2] assumes that the arcs of contact remain circular while their radii increase according to Hitchcock's formula [20]. He considered the interfacial shear stress t~ to be directly proportional to t,, depending on the friction coefficient IX through the equation t~ = IXt,, subject to the limitation that the maximum value of the interfacial shear stress would be equal to the yield shear stress of the material. He discussed the complicating factor of the inhomogeneity of deformation and introduced an adjusting factor which takes this into account. The method was too complicated to obtain an analytical solution. On account of this, other solutions based on simplifying assumptions were presented [3, 5]. Corrections for the effects of elastic entry and exit are included in the work of Bland and Ford [5]. Alexander [9] computerized Orowan's model and presented adequate predictions of roll force and roll torque. However, he did not include the inhomogeneity factor introduced by Orowan and felt the need of slip-line field solution for the accurate estimation of this factor. An upper bound solution presented by Avitzur [7], which does not rely on the assumption of \"plane sections remain plane\", gave an expression for torque and the position of the neutral point for a nonhardening material, but which does not provide roll force and pressure distribution which are important design parameters. For the cases in which roll flattening is significant and may affect torque, one has to compute roll force by some other method and calculate deformed radius of roll which is then to be substituted in the expression of torque developed by Avitzur. Recently, several attempts have been made to solve the rolling problem by the application of the finite-element technique. The primary concern is to find the roll force, torque and interfacial stresses, and a rigid visco-plastic analysis in the Eulerian reference frame is found to be most suitable. Zienkiewicz et al. [12] considered the rolled material to be rigid-visco-plastic and incompressible. They simulated the friction at the roll-strip interface by introducing a thin Analysis of flat rolling and application of fuzzy set theory 949 layer of elements whose yield strength is assumed to depend on the coefficient of friction and mean stress. The neutral point is not modeled in this method. Mori et al. [13] minimized a functional with respect to the position of neutral point in their formulation, thus making the analysis more realistic. Li and Kobayashi [ 14] developed velocity-dependent friction stress for the treatment of the neutral point problem. Assuming the existence of rigid-plastic material and rigid roll, authors have compared their predictions with the results of AI-Salehi et al. [10] and Shida and Awazuhara [ 11] and observed that there is good agreement. Hwu and Lenard [17] incorporated roll flattening and the variable coefficient of friction in the model of Li and Kobayashi. A comparison of predicted and experimental results indicates better agreement than in the case of Ref. [14]. Prakash et al. [19] presented a FEM formulation in which the neutral point is found iteratively from the condition that the interfacial shear stress changes its sign at the neutral point. In all these FEM analyses, penalty parameter formulation is used--here the selection of the proper value of the penalty parameter is important. Also, since hydrostatic pressure is divergence of the velocity times penalty constant, the accuracy of the former is very sensitive to the accuracy of the velocity field. All the above authors seem to calculate torque by integrating shear stresses along the interface. The accuracy of secondary variables viz. stresses is always lower than that of primary variables viz. velocities throughout the domain. Especially on the interface, secondary derivatives are expected to be more inaccurate, and a slight error in the position of neutral point may cause much inaccuracy in the computation of torque. This necessitates a refined mesh in the plastic zone and a very accurate velocity field. In general a number of iterations are required in these methods, which becomes of concern during mill design or when optimization results are needed for a number of different cases. None of these authors have presented results in the presence of front and back tension. Recently Dixit and Dixit [21] analyzed the wire drawing process by mixed pressure and velocity formulation, in which equations for pressure and velocity system are solved by the Householder method [22]. The drawing force is calculated not by the integration of stresses at the exit of plastic boundary, but by computing the total power of deformation. In the present paper the same methodology is extended to the problem of flat rolling. The method has provision for the presence of front and back tensions. Roll flattening is taken into account by means of Hitchctx:k's formula. Friction at the interface is modeled by the method of Wanheim [23] and Wanheim and Bay [2411 though in cold rolling where coefficient of friction is not high a Coulomb coefficient of friction delivers almost the same results. The model developed here is by no means a perfect one. There are a number of less influencing factors, which have to be considered when a precise analysis is to be made. Consideration of temperature and the strain-rate dependency of flow stress and variation of friction coefficient are a few such factors. Their inclusion in the analysis not only makes analysis complicated, but also poses the difficulty of obtaining experimental data which can model the behavior of various process parameters, thus rendering the analysis to be of academic interest only. It has been observed that in a real material flow stress cannot be reproduced to better than _+_5% accuracy [25]. There is also a limit to the precision of the reported values of other parameters. Apart from this, in metal forming some subjective information does arise when we say a particular grade of material is to be deformed in the presence of a particular lubricant. Naturally the process parameters we have in our mind are not definite numbers, but ranges of numbers in which they can lie. With the element of uncertainty present in process parameters, a designer may be interested in knowing the ranges of design parameters and the uncertainty of information associated with such ranges. Fuzzy set theory [26-29] which has been applied in a number of engineering problems can also be applied to metal forming problems. The model developed in this paper has been studied with fuzzy parameters. The initial value of yield stress, hardening coefficients and friction coefficient are treated as fuzzy numbers. Fuzzy output is presented for representative cases. It is shown that this gives a more realistic simulation of experimental results. Finally, a method to measure the reliability of a design is proposed to help the designer make decisions. Some of the relevant aspects of fuzzy-set theory are presented in appendix B. 950 U.S. Dixit and P. M. Dixit 3. ANALYSIS In the present study, only the steady-state part of the process is considered, and hence an Eulerian formulation is used. A two-dimensional (plane-strain) problem is considered. The elastic effects are neglected as they are significant only at the inlet and the exit. The strainhardening behavior is modeled, but the effects of temperature and strain-rate on the strength of the material are ignored, because the temperature rise and strain rates in a typical cold rolling operation are quite small. Furthermore, they have opposite effects on the flow strength. Roll flattening is taken into account by means of Hitchcock's formula in which the ratio of the radius of the deformed arc of contact to roll radius is given by = 1 + (1) where Fr is the roll force and 8=h~-h2 is the \"draft\" (difference in initial and final thicknesses). The constant C depends on the materials of rolls, its value for steel rolls being 4.62\u00d710'* MN m -2. Hitchcock's formula has been used here in view of its simplicity. Better treatments for roll deformation can be found in other references [16, 17]. 3.1. Material behavior In Eulerian formulation, the strain rate tensor is normally used as a measure of deformation. Here v~ is the component of velocity vector with respect to the Cartesian coordinate x~. For an isotropic rigid-plastic material, the deviatoric part Sij of the stress tensor o 0 is related to eij by the relation [30] S~j = 21~j (3) whilst the hydrostatic part or pressure (p) has to be obtained from the incompressibility constraint. For materials yielding according to the yon Mises criterion, the proportionality factor 11 is given by [30] oy I1 = (3~_) (4) where e = ( 5 ) the second invariant of eij is called the equivalent strain rate and Oy (the flow stress in tension) is assumed to be independent of strain-rate and temperature. When the loading is proportional, the flow stress of an isotropic strain-hardening material can be expressed in terms of the equivalent plastic strain g which can be obtained by integrating i~ along the particle path: g= f'o dt (6) The procedure followed for constructing particle paths and integrating the strain rates is given in [21]. For most metals, the dependence of oy on ~ can be modeled by a power law: Analysis of fiat rolling and application of fuzzy set theory 95 i (~y = ((~y)O(l + ~ ) n (7) Here ((~y)o is the yield stress of the material and b and n are the material dependent coefficients determined from the results of experiments. The mechanical behavior of a material is governed by the continuity and momentum equations. For a steady process, the Eulerian form of these equations is - 0 (8) 8%_ 8p i)S~ /)xj 3x, + ~ = 0 (9) Here in the momentum equation inertia terms have been neglected as they are very small. The domain (or the control volume) along with mesh system is shown in Fig. I. The con- ditions on the boundaries AF and DE are 1)1 = U I , I)2 := 0 on AF; v~ = U2, v2 = 0 on DE where U~ and U2 are respectively the inlet and exit velocities related by (lO) U I = U2(I -- r) (11) and r is the reduction ratio given by h i - h2 r - - - (12) hi In a rolling problem the inlet and exit velocities are not specified, instead the roll velocity is prescribed. In the present formulation the roll velocity corresponding to the specified value of U2 is obtained as the velocity at the neutral point (a point where shear stress changes its sign). The velocity field for the prescribed VR Can then be obtained by multiplying the whole velocity field by an appropriate scaling factor so as to make the velocity of neutral point equal to the roll velocity. 952 U.S. Dixit and P. M. Dixit the x2 direction on the surface except near the entry to the roll gap. Therefore, in the present work, the following boundary conditions are used, tt = 0, v2 = 0 on AB and CD (except the two nodes near entry to roll gap) (13) tt = 0, t2 = 0 on the two nodes near entry to roll gap (14) The boundary FE lies on the plane of symmetry. The symmetry implies the following conditions: tt = 0,vz = 0 on FE (15) On the roll-strip interface (boundary BC), the normal component of velocity must be zero. Thus, vn = 0 on BC (16) The second boundary condition is provided by the friction law It, I = clt.I (17) In the case of Coulomb model c is equal to B, the coefficient of friction. In the case of Wanheim and Bay 's model c is given by B\" [18], where ~la for t, < t , ' B* / Ua*(t.) for t. > t.\" The la'(t,) is given by the expression (18) < r ) . l . * ( / n ) = SS exp - - - t. L o/ '3 - t,,)t.,j (19) where ts\" and t,\" are tangential and normal stresses at the limit of proportionality and f is the friction factor related to the coefficient of friction by the relation [15] f B = (20) 1 + ~ + c o s - I f + ~(1 _ f 2 ) Furthermore, t n ' ?\u00a2 .E2-. 1 + ~+COS-y+ ~t(1 _ f 2 ) ~ ( 1 + ~1 - f ) and (21) Note that so far no boundary condition has been imposed on pressure. In finite element \"-\" = VG-- (22) O r Analysis of flat rolling and application of fuzzy set theory 953 formulation, often a spurious pressure distribution is obtained, giving rise to nonzero average values of pressure at the inlet and/or exit, herein denoted by p,~ and p .... respectively. However, in the case of zero front and back tensions, pressure values at the entry and exit should be zero. Therefore the pressure field is modified by making the average pressures equal to zero at the entry and exit. The method of modifying pressure values in the presence of nonzero front and back tensions is described in Section 3.5\u2022 3.2. Nond im en s io n a l i za t i o n The nondimensionalization of various physical quantities is undertaken using the following relationships: - - X I - - X 2 - - V I - - V 2 x, = h~/2' x2 = h-~2' v, = U22' v2 = U22 (23) - p ~ _ I.t (24) P - ((~y)o/3)' where (Gy)o (25) 11\u00b0 = 3(U21hz) Then the nondimensional versions of continuity and momentum equations are obtained by substituting equations (23)--(25) into equations (8) and (9). 3.3. F in i t e - e l emen t f o r m u l a t i o n Let vz, v2, p be the functions that satisfy all the essential boundary conditions exactly. Then v~, v2, p constitute a weak solution if the following weighted integral of the nondimensionai continuity and momentum equation is satisfied: A [ ( ~ 1 1 \"l\" ~ 2 2 ) W p \"0\" \\ ~XI \"~ ~X 2 ] wxl \"l\" ~ ~X I + ~X 2 ] 14.\"x2 ] d x t d x 2 = 0 (26) where wp, w.; and wx2 are the weight functions that satisfy the homogeneous versions of the boundary conditions and A represents the area of the domain. Integrating the second and third parts of equation (26), we obtain f ,..,..-f -f /4dF~2=O a a G I rx2 (27) where t, = - w , , [ ~ , + ~] \u2022 . .. .. Is = - .~[~,,(w) + ~z2(w)] + 21a[~,,ell(W) + e:zze2z(w) + 2~,z~,2(w)] 13 = tnwx o, I4 = t 2 w x 2 (28) (29) (30) and Fxj and Fx2 are respectively Rose pa~t_, s of the boundary where the traction components Fi and F2 are specified. The terms Etl(w), e22(w), et2(w) are the components of the tensor 1 ~(w) = ~ (Vw + (VwO) (31) 954 u.s . Dixit and P. M. Dixit where w = wx,i~, + wxffx2 (32) The finite-element formulation of the Galerkin integral and the nondimensional version of the boundary conditions are similar to that of a flow problem of a non-Newtonian incompressible fluid, the details of which are described in any standard text, viz. [31]. In the present work, 9-noded rectangular elements are used to discretize the domain (Fig. 2), with biquadratic approximations for the velocity components and bi-linear approximations for the pressure. The assembly of the elemental coefficient matrices and the right-hand side vectors into the global matrix and vector is done by transferring the elements corresponding to a local degree of freedom in each elemental matrix/vector to positions of the corresponding global degrees of freedom in the global matrix/vector. The essential boundary conditions except for those on the roll-strip interface are applied in the usual way. The conditions on the interface are applied by performing certain row operations on the global coefficient matrix and the global righthand side vector, the details of which are given in the thesis of Dixit 132]. In order to apply this boundary condition, it is necessary to know the direction of the interfacial shear stress and thus the location of the neutral point. In this formulation, the neutral point is found by minimizing total power with respect to the position of the neutral point. This is based on the upper bound theorem, the justification for which is given in Appendix A. The initial estimation for the neutral point is found by using the slab method formula [3]. Taking this point in the middle, an interval in which the neutral point may lie is assumed. By the interval reducing method [33], this interval is reduced. After the interval has been sufficiently reduced, the exact position of neutral point is obtained as a quadratic approximation. The global equation after application of all the boundary conditions is [K]IA} = {F} (33) where IK] is the global coefficient matrix, {F} is the global right-hand side vector and {A} is the global vector of primary unknowns (i.e. velocity components and pressure). 3.4. Implementat ion The lengths li and lo of the inlet and exit zones are usually taken as Analysis of flat rolling and application of fuzzy set theory 955 The value of the multiplying factor \"n\" has to be selected such that uniform conditions prevail at the beginning of the inlet zone and the end of the exit zone. After conducting several numerical experiments, a value of three was selected for this analysis. At each assumed position of the neutral point, a number of iterations may be required. According to Ref. [34], a very convenient but powerful method of acceleration has been proposed by Aitken and Steffensen. According to this method, x~, x2 and x3 denote the results of three consecutive iterations. Assuming that they approach their limit x as a geometrical series i.e. X 1 - - X X 2 - - X x 2 - X x 3 - X (35) then the limit can be calculated as x lx 3 - - ~ x - - - (36) x t - - 2 x 2 + x 3 The above procedure was tested and found to be correct to 1% accuracy for torque and force calculations. Thus for each position of neutral point, only four-five iterations are required. A total of 20-25 iterations are sufficient to give the position of the neutral point and values of roll force and torque correctly. 3.5. Modification of pressure field in presence of tensions When the front and back tensions (tf and th) are present, it does not seem possible to incorporate them through the imposition of traction boundary conditions as these boundaries fall in the rigid zone. In the present model, the following approach is proposed. It is assumed that (I) The velocity field and hence the strain rate is not affected significantly in the presence of tensions. The tensions, therefore, only influence the pressure (or hydrostatic stress). (2) The effect of tensions is experienced uniformly across a cross-section of the strip, so that the one-dimensional equations of the slab method become applicable. According to the slab method [6], the roll pressure with tensions (q) is related to the one without tensions (qo) by the relation qo-q = tfe 2~'~ on exit side (37) qo-q = the 2acv\u00b0-v) on entry side (38) Here a = Ix (39) (40) \u00a2 is the angular position of the point (i.e. the angle between the lines joining the center of deformed arc with the exit point and the particular point) and ~o is the value of q/when \u00a2 is equal to the angle of contact (o0. Since the deviatoric part is unaffected by the tensions, q - qo will be equal to p - Po where Po is the pressure (hydrostatic stress) without tensions and p is its value in their presence. Then, using equations (37) and (38), we obtain the following relation between p and Po: 956 U. S. Dixit and P. M. Dixit p = po--(tf + pavo)e ~v on exit side p = po-( tb + pavi)e 2~tvo-~'~ on entry side (41) (42) The additional terms (Pavi and Pavo) in the above equations have been introduced to take care of a spurious pressure distribution which often arises in finite element formulation. Note that in the absence of tensions (tf=tb--O), p should be equal to Po giving rise to Pavi=Pavo=O. This indeed is the condition imposed on pressure in the absence of tensions (see Section 3.1). Furthermore, the spurious pressure distribution may be interpreted as the one arising out of some nonzero value of front and back tensions. 3.6. Calculation o f secondary variables Once the solution of the problem is obtained in the form of nodal velocities and pressures for any assumed position of neutral point, the secondary quantities, viz. the roll torque, the roll pressure and the roll force are calculated as explained below: (i) Roll torque(T)-the roll torque is calculated from the relationship T = PR/VR (43) (a) where the total power P consists of the following three parts: Power required for plastic deformation (Pp). The power dissipated due to plastic deformation is given by PP= fa S~\u00b0dxldX2 (44) (b) Substitution of equations (3)-(5) into this equation leads to Pp = f O ~ dxl dx2 (45) A Power required to overcome friction at the roll-strip interface (Pr). The power dissipated due to friction is given by P,= f[ Itsllv l (46) (c) where vs is the resultant velocity along the interface and l is the arc length. The ts is calculated from equation (17). Power due to tensions (P,). The power required in the presence of front and back tensions is hi Pt = (tb--tf)-~U1 (47) (ii) Roll pressure or interfacial normal stress (t,)-while calculating tn, the stresses a~j are first calculated at 2x2 Gauss points and then they are extrapolated to various points on the roll-strip interface, after which t. is calculated from the expression t. = t.~/ (48) where t, = o ~ (49) Analysis of fiat rolling and application of fuzzy set theory 957 and ti is the unit outward normal to the interface. (iii) Roll force (Fr)-the roll force is given by F~=f'o(t.cos*-t~sinC,)d~ (50) where l is the arc of contact."
+ ]
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+ "image_filename": "designv11_6_0000858_s0379-6779(98)00128-3-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000858_s0379-6779(98)00128-3-Figure1-1.png",
+ "caption": "Fig. 1. (a) Cyclic voltammogram of a 2.37 \u00d7 10 -3 M solution of I in 0.2 M Bu4NBF4 in CH2C12. Initial potential: 0.0 V, switching potential: 1.7 V, ten recurrent sweeps. (b) Study of the deposit formed in ( a ) in 0.1 M Bu4NBF4 in CH3CN. Initial potential: 0.0 V, switching potential: 1.4 V, five recurrent sweeps. Scan rate: 100 mv s- t. Working electrode: platinum disk of diameter 1 mm.",
+ "texts": [
+ " Cyclic voltammetry analysis I is electrooxidized irreversibly and the oxidation appears as two broad peaks in the potential region at about E J = 1.5 V and E 2 = 1.65 V. These peaks probably correspond to the respective oxidation of the two fluorene units of I. When the oxidation is performed only in the potential range of the first oxidation peak E l, the polymerization occurs slowly and a new redox system is visible between 0.9 and 1.4 V. However, when the oxidation is performed in the potential range including the two oxidation peaks E 1 and E 2 as presented in Fig. 1 (a), an oxidation reduction wave appears also between 0.9 and 1.4 V; but its growth is largely more important, it corresponds to the redox reaction of the polymeric film. The electrode taken out of the solution after the tenth sweep seems unmodified because it is covered by a transparent polymer. However, the modified electrode studied in a CH3CN solution containing 0.1 M Bu4NBF 4 presents a reversible oxidationreduction system shown in Fig. l (b ) . This system is the electrochemical response of the polymer coating the platinum electrode",
+ " The increase of iv at E 1 (i(E1) ) and E 2 (i(E2) ) is linear with the concentration of I. A comparison of fluorene and I oxidations shows that, when the two substrates are in solutions of the same concentration, the oxidation peak of the fluorene (ip(fluorene) measured at 1.5 V) has an intensity lying between i(E 1) and i(E 2) of I. This may be explained by the fact that fluorene diffuses more quickly than I, ip(fluorene) is higher than i(E ~ ) of I but the oxidation of the second fluorene unit of I leads to an i(E 2) higher than ip(fluorene). Fig. 1 shows typical a cyclic voltammogram of I at stationary platinum electrodes in CH2C12 solution containing 0.2 M Bu4NBF4 and 2.37 \u00d7 10 -3 M 9,9'-spirobifluorene for the electrode potential swept continuously between 0.0 and 1.7 V. Polymerization has also been performed by oxidation of I at fixed potential. Fig. 2 presents the redox behaviour of poly(I) deposits obtained by oxidation at 1.6 and 1.9 V in CH2C12 solution containing 0.2 M B u 4 N B F 4 and 4.95 \u00d7 10-3 M 9,9'-spirobifluorene. The electrolytic medium is also CH2C12 solution containing 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001325_jsvi.2000.3040-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001325_jsvi.2000.3040-Figure6-1.png",
+ "caption": "Figure 6. Response of the controlled axially moving string with 5% white noise in the amplitude of the sinusoidal excitation. Control force q a1 (x, t)\"0; c\"0)3, d\"0)05, x 3 \"0)25, x 4 \"0)3, a 2 \"0)5.",
+ "texts": [
+ " From equation (29), it is noted that the stability of the uncontrolled string is a!ected by the boundary conditions since u(s)\"h 0 (s)h 1 (s). Consider the \"xed}\"xed boundary, h 0 (s)\"h 1 (s)\"!1. By the theorem, the string is marginally stable because Du (s) D\"1. Thus, the control forces (27) and (28) are also marginally stable. This means that the proposed active vibration control scheme is not robust enough to perform a stable control in real time under a noisy environment of practical test conditions. This is typical of a feedforward control [11]. Figure 6 shows the time response of the controlled axially moving string when there is a 5% white noise in the amplitude of the excitation force applied at x\"0)05. Only one control force q 2 (x, t) is applied at a 2 \"0)5. It is seen that the downstream vibration does not go to zero, but is bounded. However, the control force, shown in Figure 7, appears to increase unboundedly with time. It is thus necessary to resolve the robustness issue of the controllers before they can be applied for real-time control"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001925_84.388115-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001925_84.388115-Figure2-1.png",
+ "caption": "Fig. 2",
+ "texts": [
+ " We have developed a self-driven miniature car to study the locomotive mechanism and moving performance. 11. MOTOR A. Manufacturing Fig. 1 shows the schematic structure and main specifications of the micromotor manufactured for the microcar. The motor is a type of stepmotor that is electromagnetically driven. The rotor is an isotropic barium ferrite magnet. The magnet was machined into a tube shape by a cylindrical grinder. The outer and inner diameter of the tube are 1.0 and 0.25 mm, respectively. The core was then made as a 4-pole magnet by a special apparatus shown in Fig. 2. The apparatus consists of four contact probes having coils that generatea 4-pole magnetic field. The end of the contact probe has a concave shape to fit the rotor. The end firmly contacts the rotor utilizing the Manuscript received March 22, 1994; revised December 29, 1994. Subject The authors are with Research Laboratories, Nippondenso Co., Ltd., Aichi E E E Log Number 941 1737. Editor, R. 0. Warrington. 470-01, Japan. thermal expansion of the probe when the coil is activated. This enables a uniformly magnetized rotor"
+ ],
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+ },
+ {
+ "image_filename": "designv11_6_0001869_irds.2002.1043954-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001869_irds.2002.1043954-Figure2-1.png",
+ "caption": "Figure 2: Two point contact model of knotted suture",
+ "texts": [
+ " As the starting point of knot placement, we assume a simple knot is already developed by wrapping the loop strand around the post strand and by applying tension forces as shown in Figure 1. 2.2 Sliding condition Moving the knot requires sliding the two strands relative to each other. To investigate the impending sliding condition, we need to have a static force balance model. The general model of a knotted suture is quite difficult due in part of the flexibility of the suture and complex contact geometry. In this paper, we use a simplified model based on the assumption of a two-point contact between the sutures, as shown in Figure 2. The freebody diagram is shown in Figure 3. The impending sliding problem can now be stated as: Given &, @2a, A, and A, determine the relationship between the angles 11flb11 ll@\"bII yi's and pi's, i=1,2, when the sliding motion is about to begin. Define Zla = L, &a = L, Z1b = h, and IIFlaII l lFZa11 l l F l b I I Z2b = A ll&, and let Zn = e be the unit vec- tor along which the normal forces apply and Zt be the unit vector along which the frictiyn forces apply. When the knot is in equilibrium, F = 0, so FlaZia + F2aZ2a FlbZIb + F2b&b = 0"
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+ },
+ {
+ "image_filename": "designv11_6_0001615_0263-8223(93)90220-k-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001615_0263-8223(93)90220-k-Figure3-1.png",
+ "caption": "Fig. 3. Definitions of stiffnesses on a hysteresis loop.",
+ "texts": [
+ " If a material behaves as a linear-viscoelastic solid, the hysteresis loop takes the form of an ellipse. In this case eqns (3)-(5) can be solved analytically: W 1 = 7tOg Sin 6 (6a) W s = 6~ cos 6 (6b) A = ~t tan 6 (6c) where O and g represent the stress and strain amplitudes, respectively. On the other hand, the definition of the energies according to eqns (3) and (4) has the advantage that it is valid for both linear-visco- elastic materials and non-linear-viscoelastic materials. The mid-curve also enables the definition of various stiffnesses (Fig. 3). The compression stiffness at minimum load, El, emerges at the lower end of the loop and, analogously, the mean stiffness, Em, at mean strain and tensile stiffness, E u, at maximum strain: dOmc E=el =-\u00b0 tan ctl (7a) El = - ~ e e Em d\u00b0mc ~:=em O - = - tan a m (7b) de e E,, dame a = = - tan a~ (7c) The dynamic secant modulus Edy n is obtained from the maximum and minimum stress and strain: E d y n - Ou -- O1 (8) Eu -- El 3 EXPERIMENTAL EQUIPMENT AND PROCEDURE FOR HYSTERESIS MEASUREMENTS The experimental equipment is shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001338_0094-114x(95)00082-a-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001338_0094-114x(95)00082-a-Figure3-1.png",
+ "caption": "Fig, 3. Tip interference during engagement.",
+ "texts": [
+ " 2 (ring gear is the driver in gearing action) the approach contact (CP) ac, recess contact (PB) re and contact ratio Cr are expressed as a\u00a2 = x/~2p - r~,p - rp sin g (3) r~ = r~ s in ~t -- ~ - - r~g (4) C, = (ac + rc)/(zcm cos ~0) (5) Minimum tooth difference 477 where, rp and rg are the working pitch circle radii, rap and rag are the tip radii and rbp and rbg are the base circle radii of the pinion and gear respectively, ~ and ~0 are the working and standard pressure angles respectively, and m is the standard module. 3.1. Tip interference Referring to the two gear epicyclic drive the ring gear is the driver during gearing actions in both type-I and type-II transmissions. Therefore, the flank contact is such that the tip interference does not occur during disengagement if it can be avoided during engagement. Moreover, due to the presence of backlash checking of the interference at one side is sufficient. Figure 3 illustrates the condition when the engagement tip interference just exists in involute internal-external gear pair with internal, i.e. the ring gear as the driver. To avoid the tooth tip interferences the following conditions are to be satisfied [3, 7]: In the case of tip interference during engagement: Angles 0 o and 0g are calculated as follows: cos_,(r~, + A 2 - r~,) _ 0 , = \\ 2At., / ' 00 = cos - ' ( r \u2022 ' - A 2 - r.~p) + ap \\ 2Ar~p ,] (6) (7) (8) where the subscripts g and p refer to the gear and pinion respectively and 'A' is the center distance between gear and pinion"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003804_rnc.1084-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003804_rnc.1084-Figure2-1.png",
+ "caption": "Figure 2. Two inverted pendulums connected by a spring.",
+ "texts": [
+ "1002/rnc Substituting (37) into last equation \u2019Vi \u00bc 1 2 \u00f0eTi L T i Piei \u00fe zT\u00f0Xi\u00deFfiB T i Piei \u00fe zT\u00f0Xi\u00deFgiB T i Pieiui \u00fe wiB T i Piei \u00fe BT i Pieiuia \u00fe aT\u00f0X\u00deFdiB T i Piei \u00fe eTi PiLiei \u00fe eTi PiBiFT fiz\u00f0Xi\u00de \u00fe eTi PiBiwi \u00fe eTi PiBiuia \u00fe eTi PiBiFT giz\u00f0Xi\u00deui \u00fe eTi PiBiFT dia\u00f0X\u00de\u00de \u00fe 1 Z1 FT fi \u2019Ffi \u00fe 1 Z2 FT gi \u2019Fgi \u00fe 1 Z3 FT di \u2019Fdi \u00f045\u00de Substituting (39) into (45) and use \u2019Ffi \u00bc \u2019yfi; \u2019Fgi \u00bc \u2019ygi; \u2019Fdi \u00bc \u2019ydi and fact that eTi PiBi is scalar we get V : i \u00bc 1 2 eTi LT i Pi \u00fe PiLi 2 ri PiBiB T i Pi ei \u00fe 1 2 \u00f0wiB T i Piei \u00fe eTi PiBiwi\u00de \u00fe 1 Z1 FT fi \u00bd\u2019yfi \u00fe Z1e T i PiBiz T\u00f0Xi\u00de \u00fe 1 Z2 FT gi\u00bd\u2019ygi \u00fe Z2e T i PiBiz T\u00f0Xi\u00deui \u00fe 1 Z2 FT di\u00bd\u2019ydi \u00fe Z3e T i PiBia\u00f0X\u00de \u00f046\u00de Using the adaptation laws (40)\u2013(42) along with Riccati-like equation (21), we get \u2019Vi4 1 2 eTi Qiei \u00fe 1 2 r2w2 i \u00f047\u00de The conclusions of Theorem 2 can be obtained by following the same procedure as in the proof of Theorem 1. In this section, we demonstrate the effectiveness of the proposed direct and indirect adaptive fuzzy control algorithms using two illustrative examples. Example 1 A double-inverted pendulum model [19] shown in Figure 2 is considered. Each pendulum may be positioned by a torque input ui applied by a servomotor at its base. It is assumed that both yi and \u2019yi (angular position and velocity) are available to the ith controller for i=1, 2. The equations describing the dynamics of the pendulums are defined by \u2019x11 \u00bc x12 \u00f048\u00de \u2019x12 \u00bc m1gr J1 kr2 4J1 sin\u00f0x11\u00de \u00fe kr 2J1 \u00f0l b\u00de \u00fe u1 J1 \u00fe kr2 4J1 sin\u00f0x21\u00de \u00f049\u00de \u2019x21 \u00bc x22 \u00f050\u00de \u2019x22 \u00bc m2gr J2 kr2 4J2 sin\u00f0x21\u00de kr 2J2 \u00f0l b\u00de \u00fe u2 J2 \u00fe kr2 4J2 sin\u00f0x12\u00de \u00f051\u00de Copyright # 2006 John Wiley & Sons, Ltd"
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+ {
+ "image_filename": "designv11_6_0002121_jp012819k-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002121_jp012819k-Figure4-1.png",
+ "caption": "Figure 4. (a) Illustration of the origin of the attractive component of vertical vortex-vortex interaction (see Text for details). The graph in (b) shows a qualitative profile of the equilibrium separation deq between the centers of two disks as a function of their rotational speed.",
+ "texts": [
+ " The magnitude of the repulsive hydrodynamic force exerted by disk 1 on disk 2 is given by Fh,1(z) \u221d F\u03c92a1 3(z)a2 4(z)/d3, and the total repulsive force FR between the Taylor vortices is obtained by summing repulsive forces between imaginary disks at all elevations within the liquid layer: Integrating and neglecting small exponential terms, FR can be rewritten as The qualitative dependence of this force on the rotational speed is shown in Figure 3d: for small values of \u03c9, the repulsion grows with angular speed until it reaches a maximum, and it decays (approximately exponentially) for high values of rotational speeds. AttractiVe Interaction. As \u03c9 becomes larger, the repulsion described by eq 2 becomes smaller; at the same time, an attraction between disks becomes more important. Consider the flux toward the disk spinning on the lower interface (Figure 4a). The quantity of fluid Q flowing toward this disk depends on the rotational speed \u03c9 and the radius a of the disk:24 Q \u221d a2\u03c91/2. As confirmed by direct observation, the fluid is pumped onto the lower disk from the region near the upper interface. To simplify the argument, we assume that this region is a layer of constant thickness T, and consider the flow within this layer that is directed toward the axis of rotation of the lower disk (the angular component of the flow does not contribute to the transport of liquid onto lower disk)",
+ " This pressure gradient gives rise to a force FA that acts on a neutraly buoyant disk floating on the upper interface and attracts it toward the axis of rotation of the lower disk: FA(d) \u221d (Q/d)2 \u221d \u03c9/d2 (a similar force acts on the lower disks as the result of the liquid transfer from the lower interface toward the upper spinning disk). This attractive force increases monotonically with increasing rotational speed of the disks. Balance of Forces. The equilibrium separation between the axes of rotation of the disks is defined by the balance of the attractive force FA and the repulsive force FR: The qualitative dependence of the equilibrium separation on the rotational speed is illustrated in Figure 4b. At low values of \u03c9, \u03c9/deq 2 ) constant3\u03c9 3/2 exp(-4constant2h\u03c91/2)/deq 3 (3) deq \u221d \u03c91/2 exp(-4constant2h\u03c91/2) (4) FR(d) \u221d \u222bz)0 z)h F\u03c92a1 3(z)a2 4(z)/d3 dz (1) FR(d) \u221d \u03c93/2 exp(-4constant2h\u03c91/2)/d3 (2) the separation between the disks increases with \u03c9 until it reaches a maximum; past this maximum deq decreases approximately exponentially with \u03c9. Also, for a given value of rotational speed, the model predicts an exponential decrease in deq with increasing h. We experimentally observed a stronger-than-linear decrease in the equilibrium separation of disks with both h and \u03c9 (for \u03c9 > \u223c150 rpm)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003893_0301-679x(83)90004-x-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003893_0301-679x(83)90004-x-Figure2-1.png",
+ "caption": "Fig 2 Displacement transducers: (a) design (b) arrangement",
+ "texts": [
+ " Spherical samples were tested in compression, in shear around the x axis (k= in a-direction, Fig lb), and in torsion around the z-axis (k-/in ~,-direction, Fig lb). Tests were performed on universal precision testing machines - an Instron TT-DM (0.1 MN maximum capacity) and TT-KM (0.25 MN maximum capacity). These machines have very high structural stiffness and sensitive extenso. meters. However, both parameters were found to be inadequate for testing ultrathin-layered laminates in compression. Ultra-sensitive displacement transducers (Fig 2(a)) were used to eliminate the influence of the testing machine structural stiffness on test results. The transducer was machined from a solid block of low-hysteresis (spring) steel, thus eliminating friction in the joints which could affect transducer sensitivity. Four strain gauges provided compensation for machining asymmetry and thermal effects. Using good strain-gauge amplifiers, these transducers can reliably measure displacements as small as 0.05-0.1/am. Standard extensometer amplifiers were used with the testing machines to give resolutions of 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000497_a:1008966218715-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000497_a:1008966218715-Figure5-1.png",
+ "caption": "Figure 5. Local map and active circle.",
+ "texts": [
+ " Consequently, it will be time consuming to test all of these obstacle regions to see if they are associated with the clustered regions. In the presented map building method, the obstacle regions located within some distance from the mobile robot are only considered to test its association with the clustered region. We call this set of obstacle regions as local map. To select obstacle regions which included in the local map, we introduce the concept of active circle that represent the region around the mobile robot within the distance dc. Figure 5 shows the example of an active circle. The local map is composed of M1, M2 and M4. The presented world map building method then consists of the following steps. \u2022 Step 1. Determining clustered regions Ri \u2019s at the present sampling time. \u2022 Step 2. Selecting obstacle regions that are located within the local map. \u2022 Step 3. Determining the obstacle region Mk\u2019s that are associated with Ri \u2019s and updating their parameters. \u2022 Step 4. Deleting obstacle regions that are in the field of view but are not associated with any of Ri \u2019s"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.13-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.13-1.png",
+ "caption": "Figure 3.13. Finite rotations of the solar panel of a spacecraft.",
+ "texts": [
+ "150); and the resultant rotation may be found by the matrix product of the successive rotation matrices in the form provided in (3.147b ). The angle and the axis of the resultant Euler rotation may then be computed in the frame 1/J by aid of (3.89) and (3.90), as usual. It is useful to observe in calculations that the matrix of S is skew and that of a\u00ae a is symmetric. Example 3.14. The solar panel of a spacecraft receives three rotations about axes ak in the spatial frame 1/J = { 0; ek }, as shown in Fig. 3.13. The first rotation is 90\u00b0 about the panel axis a 1 ; the second is 90\u00b0 about the satellite body axis a 2 ; and the last is a 180\u00b0 turn of the satellite about the line a 3 \u2022 Find the angle and axis of the equivalent Euler rotation. What is the final orien tation in 1/J of the satellite body axis? Chapter 3 Solution. The equation for the kth rotation Rk through the angle 8k about the axis ak may be obtained from (3.150): (3.152) without sum on k. Thus, with 81 = n/2, the first rotation is given by R 1 = S 1 + a 1 \u00aea1 , wherein the axis is obtained from the geometry in Fig. 3.13: J3 1 a1=-e2+-e3 2 2 in t/J. Then use of this result in (3.151) yields the matrices -1/2 J312] 0 0 ' 0 0 0 3/4 J314 ;/4]\u00b7 1/4 referred to t/J. It follows from the formula given earlier that the matrix in t/1 of the rotation tensor R 1 = R!qepq is given by [ 0 -1/2 J312] R 1 = 1/2 3/4 j3/4 . - J312 J314 1/4 The second rotation is easily obtained by construction of a basis transfor mation array, as described in Example 3.6, or by use of the same formula given above with 82 = n/2 and a 2 = e3 \u2022 The reader will find the tensor R2 = R~eij whose matrix in t/1 is [0 -1 0] R 2 = 1 0 0 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001576_042516402776250388-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001576_042516402776250388-Figure1-1.png",
+ "caption": "Fig 1: The completed FE model of one hoof. Solar loading (LC1) is shown and described in the text. Inset shows the location of points on the wall for which principal strains were compared with in vivo data.",
+ "texts": [
+ " (1999) and with the relative strain magnitudes for the 9 gauges. In vivo strain recording Details of the experimental protocol are given by Thomason et al. (2002). Briefly, 5 small rosette gauges (element length, 2 mm) were glued one-third of the way down the right, front hoof wall of 9 Standardbred horses which were unshod but had been trimmed within the previous 3 weeks. Gauges were placed on the medial and lateral quarters and dorsum (toe) and at 2 intermediate positions called medial45 and lateral45 (Fig 1, inset). Each horse was trotted on a treadmill at velocities 3.5\u20137.5 m/s while strains were recorded for between 50 and 110 strides per velocity. Magnitudes of principal compressive strain \u03b52 at midstance were extracted from the complete records. Only values of \u03b52, for a velocity of 5.0 m/s, are used here because this is a medium-paced trot which has significance for the loading of the FE model (see below). For a tenth horse, 9 rosette gauges were attached to the hoof at the medial and lateral quarters and dorsum",
+ " In each of 3 test runs, 5 of the gauges were sampled, with 2 dorsal gauges being common to each run. Twenty or more strides per run were recorded at a trot while the animal was ridden in an indoor arena. Midstance values of \u03b52 were extracted from the records and data were pooled across runs. Rosettes experiencing the highest values were identified. Much of the preparation of the model and the analysis were run using Cosmos/M software1 on a generic Pentium 4 computer (1.3 GHz with 256 Mb RAM). Some calculations of coordinates were done in a spreadsheet2. The completed model is shown in Figure 1 and was constructed as follows on a protocol refined from that in McClinchey (2000): (1) Shape: Scaled, digital photographs were taken of each hoof in dorsal, medial, lateral and solar views. From the solar view, the coordinates of 11 points describing the border of the wall were extracted. From the other views, the following measurements were made: toe (dorsal) angle (TA), toe length (TL), medial and lateral wall angles (MA, LA), medial and lateral wall lengths (ML, LL), heel angle (HA) and medial and lateral heel bulb heights (MH, LH, measured perpendicular to the ground)",
+ " (c) Expansion of shell in B to wall (W) in 2 layers, laminar junction (LJ) and sole (S). (d) Addition of solar dermis (SD) and distal phalanx (PIII). (4) Loading and boundary conditions: The forces and moments acting on PIII during stance are not amenable to direct measurement, but ground reaction forces (GRF) have frequently been recorded (Merkens et al. 1993). For this reason, each model was loaded sequentially in 2 ways. In loading condition one (LC1, solar loading), a uniform pressure was applied to each node on the solar bearing surface of the wall (Fig 1). Magnitude of the pressure was calculated by dividing the area of the bearing surface into a force of 1.15 times the known body mass of each animal. The resultant force on the hoof was equivalent to the peak vertical GRF recorded for horses at a medium-paced trot (Merkens et al. 1993). On the dorsal surface of PIII, 121 nodes were constrained from displacing (Fig 1). The nodes were located near the centre of PIII so stress concentrations around them would be confined within the block and not radiate into surrounding tissue layers. When the analysis was run, reaction forces were calculated at each of these nodes and deriving these forces was the whole purpose of LC1. In loading condition 2 (LC2, skeletal loading), the reaction forces resulting from LC1 were applied to the top of PIII and the distal bearing surface of the wall was partially constrained from moving",
+ " This is equivalent to the hoof being prevented from indenting the substrate but being free to lift from it or slide on it. Two nodes on the bearing surface, at junctions of toe and each quarter, were constrained completely to prevent whole body motion of the model. Only results of LC2 are presented here, because LC1 was just to provide appropriate loads on PIII. (5) Presentation of results: Each model was compared with digital photographs of the real hoof to ascertain which nodes corresponded most closely in position to the location of the 5 rosette gauges (Fig 1, inset). Magnitudes of principal strains \u03b51 and \u03b52 at each node were extracted from the analysis of LC2 and were compared with the corresponding in vivo values. At each site, the predicted value of compressive principal strain \u03b52 were expressed as a percentage of the mean in vivo values, for comparison. Predictions were individually tested for similarity to the mean in vivo values (i.e. lack of statistical difference) using t tests of single values vs. sample means at an alpha level of 0.01. This stringent level broadened the band in which strain values would not be distinguished as different"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001059_12.403696-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001059_12.403696-Figure5-1.png",
+ "caption": "Figure 5. Kinematic model of a flexure hinge with unreeling centroides",
+ "texts": [
+ " If only the deflections are of interest and not the effecting loads and stresses the stress-strain relationship of the material has no influence. Also the factor n, thus a working tensile force or compressive force, and the transverse force Q do not have big influence to the deflection curves of notch flexure hinges from a certain length for l2 up.8,10 Now if the deflection curve of one point of the flexure hinge is well-known during load, the movement of the center of rotation can be calculated. The movement of a body in a plane can always be described by an unreeling movement of a moving centroide on a fixed centroide (fig. 5).11 The curve of the instantaneous centers of rotation can now be determined either graphically or computationally from the coordinates (xB, zB, \u03c6B) of the deflection curve. The coordinates of the instant centers at different joint angles are given by: B B BP d dy xx \u03c6 \u2212= , (11) B B BP d dx yz \u03c6 += . (12) Because the coordinates of point B are determined discretely, xP and zP must be calculated over the difference quotient. A second possibility of calculating xP and zP is to derive functional dependencies yB = f (\u03c6B) and xB = f (\u03c6B) and afterwards form the differential quotient"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure4-1.png",
+ "caption": "Fig. 4 Scheme of the friction testing apparatus",
+ "texts": [
+ "3 per cent carbon and HV \u02c6 205 for the axle (A1N-UIC 811\u00b11 O) and a quenched and tempered steel with 0.5 per cent carbon and HV \u02c6 260 for the wheel (R7T-UIC 812\u00b13 O). The initial specimens roughness was Ra \u02c6 0.8 mm for the axle and Ra \u02c6 1.5 mm for the wheel. As stated above, the test apparatus was designed to be mounted on a standard axial testing machine. In particular, in the present experiment a servo-hydraulic INSTRON machine with a maximum load of 100 kN and a maximum grip distance of 300 mm was used. The scheme of the device is shown in Fig. 4. Two couples of the specimens are present in a symmetrical position, in order to avoid bending and torsional effects. The bodies are mounted on a central slide attached to the lower grip of the testing machine, while the punches are mounted on two lateral walls, attached to the higher grip of the machine. Spherical joints are present between the apparatus and the machine grips, in order to avoid any problem of misalignment. A normal load N is applied during the test by means of a bolt, with pivoted axial rolling bearings under the bolt head and under the nut, to avoid the transmission of a torque to the walls during the tightening operation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002912_6.2004-4911-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002912_6.2004-4911-Figure2-1.png",
+ "caption": "Figure 2: EADS-Quattrocopter MAV",
+ "texts": [
+ " MEMS Components Flight Testing To perform investigations on MEMS-based micro-avionics systems and miniaturised autopilots suited for flight control of MAVs, a rotary wing MAV was designed as a flying testbed. The rotary wing configuration was chosen because it offers the higher challenge for MAV flight control compared to a fixed wing configuration. This MAV serves also as a testbed to investigate the capabilities of small scale hovering surveillance platforms. The so called Quattrocopter (see Fig. 2) is an electrically driven rotary wing platform with four fixed pitch rotors (no swash plates). The flight control is performed through the variation of the motor speed. It has an overall size of 65 cm and a total weight of approximately half a kilogram. The Quattrocopter is designed for a flight duration of about 25min with one charge of the lithium batteries. The micro avionics is comprising a 6DoF MEMS IMU, a pressure sensor, 16bit A/D conversion, a GPS module, a RC-control receiver and power amplifiers for motor control"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000885_s0263-8223(00)00103-3-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000885_s0263-8223(00)00103-3-Figure7-1.png",
+ "caption": "Fig. 7. The distribution of the residual stress component of rx for the 90\u00b0 orientation angle.",
+ "texts": [],
+ "surrounding_texts": [
+ "5. Results and discussion\nAll the results in this study are found from the analytical solution. When the bending moment values reach the values in Table 2, plastic yielding occurs. As seen from this table, the bending moment which starts the plastic yielding is maximum for the orientations angle of 0\u00b0, as 12629.3 Nmm. It is minimum for the orientation angle of 90\u00b0, as 1706.7 Nmm.\nElastic, elastic\u00b1plastic and residual stress components for 0\u00b0, 30\u00b0, 45\u00b0, 60\u00b0 and 90\u00b0 orientation angles are given in Table 3. As seen from this table, maximum residual stress component is found at upper and lower surfaces. It is the greatest value for the orientation angle of 0\u00b0 as \u00ff17:30 MPa at the lower surface. When the orientation angle is increased, the residual stress component of rx becomes smaller. When h 2 mm, the equivalent plastic strain is maximum for 30\u00b0 orientation angle as 0.9%.",
+ "The displacement components at the mid-point of the free end x 0; y 0 are given in Table 4. As seen from this table, the vertical displacement component v is larger than the horizontal displacement u. The vertical displacement component is maximum for the orientation angle of 30\u00b0 as \u00ff5:98 mm for h 2 mm.\nThe distribution of the residual stress component of rx for the 0\u00b0 orientation angle is shown in Fig. 3. As seen from this \u00aegure, the intensity of the residual stress component is maximum at the upper and lower surfaces for h 4 and 6 mm. But it is maximum at the boundary of the elastic and plastic regions for h 2 mm. The distribution of the residual stress component of rx for 30\u00b0, 45\u00b0, 60\u00b0 and 90\u00b0 orientation angles is shown in Figs. 4\u00b17, respectively. As seen from these \u00aegures, the intensity of the residual stress component rx is maximum at the upper and lower surfaces or at the boundary of the elastic and plastic regions for h 6 and 4 mm. But it is maximum for all the cases at the boundary of the elastic and plastic regions for h 2 mm. It varies nearly linearly in the plastic region for small plastic deformations.\n6. Conclusion\nThe following conclusions are obtained from the analytical solution of the composite cantilever beam: 1. The intensity of the residual stress component of rx is\nmaximum at the upper and lower surfaces or at the boundary of the elastic and plastic regions. 2. If the plastic region is increased further, maximum residual stress is obtained at the boundary of the elastic and the plastic regions. 3. The vertical displacement is larger than the horizontal displacement. 4. The beam gives the greatest vertical displacement at the mid-point of the free end for the orientation angle of 30\u00b0. 5. The residual stress component of rx is the greatest for the orientation angle of 0\u00b0. 6. Maximum equivalent plastic strain is obtained for the orientation angle of 30\u00b0 at h 2 mm.\nReferences\n[1] Jegley D. Impact-damaged graphite-thermoplastic trapezoidal-\ncorrugation sandwich and semi-sandwich panels. J Compos Mater 1993;27(5):526\u00b138. [2] Marissen R, Brouwer R, Linsen J. Notched strength of thermo-\nplastic woven fabric composites. Compos Mater 1995;29:1544\u00b164. [3] Cantwell WJ. The in\u00afuence of stamping temperature on the\nproperties of a glass mat thermoplastic composites. J Compos Mater 1996;30(10):1266\u00b181.",
+ "[4] Shi FF. The mechanical properties and deformation of shear-\ninduced polymer liquid crystalline \u00aebers in an engineering thermoplastic. J Compos Mater 1996;30(14):1613\u00b126. [5] Tavman IH. Thermal and mechanical properties of aluminium\npowder \u00aelled high-density polyethylene composites. J Appl Polym Sci 1996;62:2161\u00b17. [6] Miyazaki M, Hamao T. Solid particle erosion of thermoplastic\nresins reinforced by short \u00aebers. J Compos Mater 1994;28(9): 871\u00b183. [7] Jeronimidis G, Parkyn AT. Residual stress in carbon \u00aebre\u00b1\nthermoplastic matrix laminates. J Compos Mater 1998;22-5:401\u00b1 15. [8] Domb MM, Hansen JS. The e ect of cooling rate on free-edge\nstress development in semi-crystalline thermoplastic laminates. J Compos Mater 1998;32(4):361\u00b185. [9] Akay M, Ozden S. Measurement of residual stresses in injection\nmoulded thermoplastics. Polym Test 1994;13:323\u00b154.\n[10] Akay M, Ozden S. In\u00afuence of residual stresses on mechanical\nand thermal properties of injection moulded polycarbonate. Plastics, Rubber and Compos Processing Appl 1996;25(3): 138\u00b144.\n[11] Karakuzu R, Sayman O. Elasto-plastic \u00aenite element analysis of\northotropic rotating discs with holes. Comput Struct 1994; 51(6):695\u00b1703. [12] Karakuzu R, Ozel A, Sayman O. Elasto-plastic \u00aenite element\nanalysis of metal-matrix plates with edge notches. Comput Struct 1997;63(3):551\u00b18. [13] Sayman O. Elasto-plastic stress analysis in stainless steel \u00aeber\nreinforced aluminum metal laminated plates loaded transversely. Compos Struct 1998;43:147\u00b154. [14] Karakuzu R, Ozcan R. Exact solution of elasto-plastic stresses in\na metal-matrix composite beam of arbitrary orientation subjected to transverse loads. Compos Sci Technol 1996;56:1383\u00b19. [15] Sayman O, Kayrici M. An elastic\u00b1plastic stress analysis in a\nthermoplastic composite cantilever beam. Compos Sci Technol 2000;60:623\u00b131. [16] Lekhniskii SG. Anisotropic plates. London: Gordon and Breach,\n1968.\n[17] Jones RM. Mechanics of composite materials. Tokyo: McGraw-\nHill Kogakusha, 1975.\n[18] Owen DRJ, Hinton E. Finite elements in plasticity. Swansea:\nPineridge, 1980."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-8-1.png",
+ "caption": "Figure 1-8. Interferometric set-up combined with a 3 x 3 coupler arrangement for phase demodulation (according to [429])",
+ "texts": [
+ " Stripe waveguides (diameter approximately 5 urn) at higher refractive index are placed in parallel at a distance such that the evanescent fields can cross-talk from the first waveguide to the second. Such devices are frequently used in telecommunications for phase decoding. For this reason, they are available in various structures [20] and at reasonable prices. A typical form is the socalled 3x3 coupler, shown schematically in Figure 1-7. 14 l Opto-Chemical and Opto-lmmuno Sensors 1.2 Principles of Optical Transduction 15 Combination of such signal processing units with interferometers supply sensitive sensing properties. A complex set-up is shown in Figure 1-8 [429]. Additional literature is cited in Table 1-4. 16 l Opto-Chemical and Opto-Immuno Sensors Surface Plasmon Resonance (SPR) The principle has been explained in Section 1.2.2. Two types of excitation of the surface plasmon resonance [254, 368] are possible: (a) The angle of incidence of monochromatic light is varied. The resonance condition is monitored by use of a position-sensitive linear photodiode array [294]. This principle is commercialized by Pharmacia. At present it is one of the most commonly used bioanalytical systems for examining affinity reactions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.3-1.png",
+ "caption": "Figure 1.3. A simple mechanical system in which a small body P is modeled as a particle.",
+ "texts": [
+ " In the preceding example, we started from a given motion relation and derived the velocity and acceleration from it. Most of the time, however, we must obtain the motion relation from other data provided in the problem. Let us look at an illustration of a simple mechanical system in which the motion is obtained by construction of the position vector from geometrical con siderations. Example 1.3. The hinged support H of a thin rod of length L to which a small ball Pis attached moves with constant angular speed d8(t)jdt = w on a vertical circle of radius R as shown in Fig. 1.3. We wish to determine the velocity and acceleration of the ball as it moves in the plane relative to frame t/1 = { 0; i, j} which is fixed in the plane space at 0. Solution. Since the size of P, though unspecified but finite, is apparently very small compared to the lengths L and R, it is reasonable to model P as a particle attached to the end point of the rod. Then, in terms of the angles 8 and ifJ shown in Fig. 1.3, the position vector of P in the fixed Cartesian frame t/1 is given by xi/I(P, t) = x(t) i + y(t) j = [R cos 8(t) + L cos ifJ(t)] i + [R sin 8(t) + L sin f/J(t)] j. * The angular velocity vector ro will be defined carefully in Chapter 2; its magnitude, the angular speed, has the same physical interpretation illustrated in this simpler intuitive setting. 12 Chapter 1 Hence, recalling that 0 = w, we find with ( 1.8) and ( 1.9) that relative to frame 1./J v\"'(P, t) = -(Rw sin 8+ L~ sin ifJ) i + (Rw cos 8+ ~cos ifJ)j, a\"'(P, t) = - (Rw 2 cos 8 + L~2 cos ifJ + L(fi sin ifJ) i ( 1",
+ "* Clearly, its physical dimensions are [T- 2]; and its usual measure units are rad/sec2\u2022 Notice that the same result would be obtained were we to consider, more precisely, that L was the distance from the support H to the center of the ball at P, or to any other point in the ball. In this case it makes no difference what the dimensions of the ball may be. D Example 1.4. Determine the velocity and acceleration of the ball P relative to a moving reference frame J1. = { 0; e 1 , e2 } fixed in the wheel of the device shown in Fig. 1.3. Solution. To find the velocity and acceleration of P relative to a moving frame J1. = { 0; ek} fixed in the wheel at 0, we first write its position vector relative to frame J-L: x1_.(P, t) = R + L[cos ifJ(t) e1 +sin ifJ(t) e2 ] where now R is the constant vector of H from 0. Hence, with (1.8) and (1.9), we find relative to frame J1. v 1-'(P, t) = L~[ -sin ifJ(t) e 1 +cos ifJ(t) e2], a~-'(P, t) = -L[{fi sin ifJ(t) + ~2 cos ifJ{t)] e 1 (1.18) + L[{ficosifJ{t)-~2 sinifJ(t)] e2 \u2022 Notice that in the moving frame J-1",
+ " But a constant speed by itself does not constitute a uniform motion because there are infinitely many paths along which a particle may travel with a con stant speed. A straight line is only one of them. An example of another one studied earlier is the helical path ( 1. 7) for which the constant speed was found to be v = ( w 2 R 2 +A 2 ) 112. For the given initial data x0 and v0 , there is one and only one uniform motion (1.55); but for the same x 0 and v0 there are infinitely many motions of P for which only the speed is uniform. Example 1.9. Suppose that the hinge point H of the system shown in Fig. 1.3 moves with a constant speed v = 2 m/sec on a circle of radius Solution. The position vector of H in 1/1 = { 0; i, j} is given by x(H, t) =50( cos 8 i +sin 8 j) em, where 8(t) denotes the angular placement of H measured from the fixed ver tical line shown in Fig. 1.3. Application of (1.8) to the last equation gives v(H, t) = 508(- sin 8 i +cos 8 j) em/sec. Therefore, after a change of units, I vi= 508 = v = 200 em/sec shows that 8 = 4 rad/sec, which is the constant angular speed of H about point 0 in 1/J. It is now easy to show with (1.9) that a(H, t) = -8(cos 8 i +sin 8 j) m/sec 2, whence follows la(H, t)l = 8 m/sec 2 . The point H has a constant speed; but this result shows that its acceleration is not zero because the velocity vector is changing its direction asH rotates around 0",
+ " At the other extreme, a rigid body is a body with the property that the straight line distance between every pair of its particles is constant in time. This idealization of a body that cannot be deformed, however great may be the forces and torques that act upon it, is so intuitively natural that it is often used without mention. The reader surely will recognize that our basic definition of a reference frame embodied the concept of rigidity. In fact, there were sev,eral occasions in Chapter 1 where the concept was quietly invoked. In particular, it was tacitly supposed for the mechanical device shown in Fig. 1.3 that the radius R of the wheel and the length L of the hinged rod did not vary with time. These are typical examples of rigid bodies whose motions will be investigated in this chapter. The kinematics of a rigid body in general motion in space will be studied. The main objective will be to learn how the velocity and acceleration of the particles of a rigid body are related to the translational and rotational parts of its motion. The theory of the motion of a rigid body rests upo111 a fundamental theorem due to Euler (1775)",
+ "30) for the rigid body velocity and acceleration of a particle P rotating on a circle of radius p with angular speed (J about a fixed axis a= b. 2.14. Use the geometrical interpretations of the terms in (2.27) and (2.30) to determine the velocity and acceleration of the rim particle P in Fig. 1.14. Check your solutions against (1.78). See Example 1.8. 2.15. Apply equations (2.27) and (2.30) to determine for the conditions specified in Problem 1.12 the velocity and acceleration of the mass M. Note the geometrical nature of the terms computed. 2.16. Employ (2.27) and (2.30) to find the velocity and acceleration of the ball P in Fig. 1.3. Use the conditions described in Example 1.3, and compare your results with those in ( 1.17 ). Observe the geometrical character of the terms computed. 2.17. The slider block of a machine oscillates along a straight line; and at the instant illustrated, it has a speed of 30ft/sec and is accelerating at 10 ftjsec 2 toward the right. The connecting rod AB has an angular speed of 4 rad/sec and an angular acceleration of 8 rad/sec2 clockwise about its hinge at A, and the rod is in a vertical position"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001444_48.286641-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001444_48.286641-Figure1-1.png",
+ "caption": "Fig. 1. Mathematical model.",
+ "texts": [
+ " The surface wake of an undersea towed body seems to simulate a similar situation, since the wavelengths involved in its wake can be as long as 60 meters, and produce magnetic fields greater than nT at a 10 km distance along its track. The most sensitive magnetometers or gradiometers available use SQUID technology and have a sensitivity of about II. MATHEMATICAL FORMULATION The mean free surface of the sea is taken to be the plane z = 0 in a rectangular coordinate system, with the z axis directed upward into air, the 2 axis along the direction opposite to that in which the body is traveling, and the y axis chosen to form a right-handed triad. We assume that BE (the geomagnetic induction) is constant everywhere (Fig. 1). Here i , j , k are unit vectors along the three coordinate axes, y is the angle between the 2 axis and magnetic north, and I is the dip angle. We can write: BE = F( icos lcosy + j c o s I s i n y - ks inI ) (1) nT. where F is the magnitude of BE. 0364-9059/94$04.00 0 1994 IEEE 194 Here, we assume the body is located at the point z = -h at time t = 0, and is traveling at a uniform speed U in the \u201c-x\u201d direction. Let q(z , y, z , t) be the velocity of the fluid, which is entirely due to the moving body\u2019s passage, with all other ocean phenomenon such as wind-generated waves and ocean swells being ignored"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002572_robot.1996.506595-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002572_robot.1996.506595-Figure6-1.png",
+ "caption": "Fig. 6 Simulation result with collision avoidance",
+ "texts": [
+ " The path for the case when the position and the orientation of the object are fixed has 0.0549 as the value of S. In the case of Fig.3, total value of variations of joint variables becomes smaller by moving the manipulator-A. From this result the meaning of the pseudo inverse is understood. Fig.4 shows the result considering obstacle avoidance. The value of S is 0.0198 for this case. The obstacle is avoided by using the pokential function in eq.(47). Next, 3-dimensional example is considered. Fig.5 shows the simulation result with y = 0 in eq.(48) and Fig.6 shows the result with collision avoidance. 7 Conclusions Our purpose of this paper was to propose an algorithm to plan the cooperative collision free motion for two manipulators system. In general, the two manipulators system has redundancy. By using the redundant degrees of freedom, the desired cooperative motion which executes the specified task can be planned. The potential function method is used for collision avoidance. Numerical examples show the effectiveness of the proposed method. References [l] C"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002581_robot.1996.503837-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002581_robot.1996.503837-Figure2-1.png",
+ "caption": "Figure 2: The compass gait. During single support, the hip follows the arc of a circle with radius equal to the stance leg length. At exchange of support, there is an instantaneous change in linear velocity of the hip.",
+ "texts": [
+ " In the single support phase, the stance leg is in contact with the ground and carries the weight of the biped, while the swing leg usually moves forward in preparation for the next step. At exchange of support the weight of the robot is transferred from one leg to the other. In this section, we examine exchange of support, discuss why it might not be smooth, and present a set of constraints which ensure smooth exchange of support. Inman et al. [lo] examined bipedal walking in humans and proposed a model of bipedal walking based on the compass gait (Figure 2) . In this gait the leg lengths are fixed, so t,he hip trajectory follows the arc of a circle as the biped pivots about the distal end of the stance leg. At exchange of support, the stance and swing legs trade roles, and the hip begins to follow the arc of a new circle. Because the origins of the two circles are .not coincident, the hip trajectory contains a cusp at exchange of support. Velocity vectors vand v+ attached to the hip trajectory at a cusp indicate translational velocity of the hip just before and just after exchange of support, respectively"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001440_s0925-4005(00)00722-x-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001440_s0925-4005(00)00722-x-Figure2-1.png",
+ "caption": "Fig. 2. Pool optode based on renewable reagent system operated in batch mode.",
+ "texts": [
+ " The pipette tip was then loaded with reagent solution and \u00aexed onto the end of the bifurcated \u00aebre optic supported in the syringe body. A hole was punched out of the side of the pipette to relieve backpressure and to enable solution of ions to diffuse through the membrane without producing a pressure differential. The pool optodes of the design shown in Fig. 1(a) and (b) are of low cost and relatively easy to prepare. For renewable reagent scheme, the pool optode was also incorporated with pumping system for delivering reagent from a reservoir into the pool via capillary tubing having dimensions similar to the \u00aebre optics (Fig. 2). Reagent pumping was performed by means of syringe pump, which can deliver small volumes in a reproducible manner. Other feature of the pool optode includes its use as a disposable system for single-shot analysis. In order to achieve maximum sensitivity, the pool optode was operated in a batch mode. That is, for each measurement the pool of reagent was immersed and stopped for a \u00aexed period of time to preconcentrate analyte until the reaction achieved the steady state. Once measurement has been made, the used reagent was removed from the pool by pumping fresh reagent",
+ " Therefore, it allowed greatly reduced recovery times compared to that obtained with immobilised reagent based sensor. The effects of different parameters on the sensor response were also studied. Initially, the solutions safranin and potassium iodide were added to form a mixture. The solution mixture was kept at room temperature ( 228C), and a small portion of this mixture was added to the probe head, to form the pool optode reagent solution. For operation in this system, the pool optode was immersed in a batch of sample solution (Fig. 2). In order to accelerate the reaction, a magnetic stirrer was also used. The signal response of the mercury sensor was measured at an optimum wavelength of 620 nm (Fig. 3). Each of the pool optode design was tested towards reaction with Hg(II) ion. The responses of the pool optode designs recorded as a function of time are shown in Fig. 4. The principle disadvantage of the probe head of the \u00aerst pool design (Fig. 4(a)) is the slow response and slightly lower levels of signal yielded. Furthermore, it also suffers from sensor to sensor irreproducibility and, as a result, the reproducibility of Na\u00aeon \u00aelm thickness could not be guaranteed in such a design due to the \u00aelm being formed at an angle of 458"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000629_0302-4598(94)01772-s-FigureI-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000629_0302-4598(94)01772-s-FigureI-1.png",
+ "caption": "Fig. I. Typical cyclic voltammograms demonstrating the mediated electron transfer of EEO-SOD(Cu 2+, Zn 2+) by the M V 2 + / M V + couple in DMSO solutions containing 0.I M TEAP and ( . . . . . . ) 2 mM PEO-SOD(Cu 2+, Zn2+), ( . . . . ) 0.2 mM MV 2+ or ( ) 0.2 mM MV2++ 2 mM PEO-SOD(Cu 2+, Zn 2+) under a nitrogen atmosphere. Potential scan rate: (a) 10; (b) 100; (\u00a2) 500 mV s - I .",
+ "texts": [],
+ "surrounding_texts": [
+ "Methyl viologen was found to efficiently mediate the electron transfer between polyethylene oxide-modified superoxide dismutase and the electrode in dimethyl sulphoxide media. Based on the potential-step chronoamperometric experiments, the rate constant for the mediated electron transfer was estimated to be = (1-2) \u00d7 103 M- 1 s- 1.\nKeywords: Mediated electron transfer; polyethylene oxide-modified superoxide dismutase; methyl viologen\n1. Introduction\nSuperoxide dismutases (SODs), which efficiently catalyse the dismutation of superoxide ion to H20 2 and 0 2 via a cyclic oxidation-reduction mechanism, are essential metallo-enzymes and are found in virtually all organisms [1-3]. So far there have been few electrochemical studies on electron transfer of SODs, although it has been well recognized that information on electron transfer is very useful in understanding the intrinsic thermodynamic and kinetic properties and in the practical development of the SOD-based biosensors [1-4]. Recently, Iyer and Schmidt [5] observed the direct, irreversible oxidation of copper-zinc SOD at a bare Au electrode in phosphate buffer solution of pH 4.0, and suggested that a conformational change occurs at the active sites via its adsorption on the electrode surface, thus facilitating direct electron transfer. Borsari and Azab [6] also reported the successful use of some promoters in obtaining the reversible redox response of copper-zinc SOD at an Au electrode in NaC104 aqueous solution (pH 7.2).\nThis type of study concerning the direct electron transfer of SODs seems limited because of their intrinsic electroinactivity, i.e. they lack an external pathway for electron transfer from the protein surface to the active site. On the other hand, the so-called mediated\n* Corresponding author.\n0302-4598/95/$09.50 \u00a9 1995 Elsevier Science S.A. All rights reserved SSDI 0302-4598(94)01772-7\nelectron transfer is possible for such an intrinsic enzyme by using freely mobile, soluble redox species which efficiently mediate electron transfer between the active site of the enzyme and the electrode. In order to clarify the mediated electron-transfer properties of SODs, we have been investigating their electrochemical behaviour. In this paper, we report the preliminary results of the mediated electron transfer of polyethylene oxide (PEO)-modified SOD by methyl viologen (MV 2+) in dimethyl sulphoxide (DMSO) media. The chemical modification of SODs by covalent attachment of PEO to them has recently become of great interest from the viewpoint of increasing in vitro stability, in vivo half-life and protein solubility and decreasing immunogenicity [7,8]. In this study, the main purpose of modifying SOD by PEO with amphiphilic properties is to increase the solubility of SOD in DMSO.\n2. Experimental\nBovine erythrocyte copper-zinc superoxide dismutase (SOD(Cu2+-Zn2+), 3000 units mg -1) was purchased from Wako Pure Chemical Industries (Osaka, Japan). Methyl viologen dichloride (MVCI 2) was obtained from Aldrich. A 0.1 M tetraethylammonium perchlorate (TEAP) solution was used as the supporting electrolyte in dimethyl sulphoxide (DMSO). Polyethylene oxide (PEO)-modified SOD (Cu 2\u00f7, Zn 2\u00f7) (abbreviated as PEO-SOD (Cu 2\u00f7, Zn 2+) henceforth)",
+ "was prepared from PEO monomethoxyl ether (molar mass = 5000) according to the published procedure [9]. The modification percentage was estimated to be about 35% based on the data concerning the percentage of lysines on SOD (Cu 2\u00f7, Zn 2+) (20 per SOD(Cu 2+, Zn z+) dimer) derivatized with PEO [9]. Thus, the molecular weight of the PEO-SOD(Cu 2\u00f7, Zn 2\u00f7) was calculated to be ca. 67 700.\n[CH 30\"(\" CH 2CH 20-~n CCH zCH 2~-- N]m-- ~\n0 u H x (NH2)20.m\nm - 7 , n - l 1 2\nPEO-SOD(Cu 2+, Zn 2+ )\nCyclic voltammetric and potential-step chronoamperometric experiments were carried out using a three-electrode system. A glassy carbon disc (GC-20; Tokai Carbon, diameter 1.0 mm) was used as the working electrode, a platinum wire as the auxiliary electrode and Ag/AgCIO 4 (0.01 M Ag +) as the reference electrode. A cell for a small-volume sample (about 0.2 ml) working under a nitrogen atmosphere at 25 + 2\u00b0C was used. The surface of the glassy carbon electrode was polished before each use with 0.3 /zm alumina powder (Marumoto Kogyo) on a microcloth wetted with deionized water obtained with a Milli-Q water system (Millipore), and was successively carefully sonicated in water and rinsed with water and DMSO.",
+ "diated electron transfer of PEO-SOD(Cu 2+, Zn 2+) by the MV2+/MV + couple:\nM V 2 + + e . ~ M V + 1 (1) kz I\nM V + + P E O - S O D ( C u 2 + ' Z n 2 + ) * M V 2 + + P E O - S O I M C u + , Z n 2 + ) (2)\nThe potential-step chronoamperometric experiments confirmed the above-mentioned cyclic voltammetric results. The typical results for the reduction of MV 2+ to MV + in the absence and presence of PEOSOD(Cu 2+, Zn 2+) are shown as Cottrell plots in Fig. 2. The linear Cottrell plot was, as expected, obtained in the absence of PEO-SOD(Cu 2+, Zn2+), and the slope gave the diffusion coefficient of MV 2+ as 4.8 \u00d7 10 -6 cm 2 s-l. On the other hand, such a linear Cottrell plot was not obtained in the presence of PEO-SOD(Cu 2+, Zn2+). That is, at electrolysis times shorter than ca. 30 ms the current was almost the same as that in the absence of PEO-SOD(Cu 2+, Zn2+), whereas at longer electrolysis times the increment in the current (in comparison with the current obtained when PEOSOD(Cu 2+, Zn 2+) is absent) was observed and it became larger. The increased reduction current is due to the mediated electron-transfer reaction of PEOSOD(Cu 2+, Zn 2+) (Eq. (2)). The data in Fig. 2 were replotted as the current ratio (IMed/I) against t x/2 (Fig. 3), where Iraeu and I represent the reduction current of M V 2+ to M V + in the presence and the absence, respectively, of 2 mM PEO-SOD(Cu 2+, Zn2+). Curves 1-6 are those calculated for typical\nvalues of the rate constant (k 2) for the electron-transfer reaction (Eq. (2)) using the following equation [10]:\nIMeai =/~1/2[ 'WI/2 erf(A1/2)\nwith\nA = ( k 2 C s o D t ) 1/2\nexp(-A) ] + A1/2 (3)\n(4) where Cso D is the concentration of the Cu 2\u00f7 active sites in the PEO-SOD(Cu 2\u00f7, zne+). From Fig. 3, the value of k 2 was estimated to be ca. (1-2) x 103 M-1 S -1 .\nIn conclusion, the mediated electron transfer of PEO-SOD(Cu 2\u00f7, Zn 2+) by the MV2+/MV + couple in DMSO media was observed for the first time by cyclic voltammetry and potential-step chronoamperometry, and the rate constant for the homogeneous electron-transfer reaction between MV \u00f7 and PEOSOD(Cu 2\u00f7, Zn 2\u00f7) was estimated. A related study using other redox mediators is in progress.\nAcknowledgements This work was financially supported by a Grant-inAid for Scientific Research (No. 05453117) and for Priority Area Research on New Development of Organic Electrochemistry (Nos. 05235214 and 06226222) from the Ministry of Education, Science and Culture, Japan, and the Nissan Science Foundation."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.7-1.png",
+ "caption": "Figure 4.7. Multiple reference frames applied to the complex rotations of a robot.",
+ "texts": [
+ " However, use of consecutive numerical labels that reflect the chain of angular velocities Motion Referred to a Moving Reference Frame and Relative Motion 245 involved in the problem usually is more convenient, especially for the com putation of the total angular acceleration studied later. In any case, care must be exercised to name and identify the various frames or the bodies in which the frames are imbedded. D Example 4.5. Recall the data for the moment of interest t 0 described in Example 4.1, and suppose further that the claw attached to the telescopic arm of the robot turns about the arm axis with an angular velocity co 3 = 0.1 y rad/sec relative to the arm, as indicated. The data are shown in Fig. 4.7, in which four appropriate reference frames also are defined. Find for the instant t0 the total angular velocity of the claw in the machine frame 0, but referred to frame 1 fixed in the yoke. Solution. Let us write co32 = 0.1 y radjsec for the angular velocity of the claw frame 3 ={A; y, e, f} relative to the arm frame 2 = { 0; y, i', j} whose angular velocity relative to the yoke frame 1 = { 0; i, j, k} is written as co 21 = co2 = 0.2j rad/sec. Let COw= co 1 = 0.5k rad/sec denote the angular velocity of the yoke frame 1 relative to the preferred, machine frame 0 = { 0; I, J, K }",
+ " The frames and angular velocity vectors are shown in Fig. 4. 7, but now we shall ignore the special numerical values assigned before. We want to find the total angular velocity and angular acceleration of the claw in the machine frame, but referred to the yoke frame. Let ~ be the angular speed of the claw relative to the telescopic arm; write iJ for the angular speed of the arm relative to the yoke, and let li denote the angular speed of the yoke relative to the machine frame. Then the corresponding relative angular velocity vectors indicated in Fig. 4.7 are given by (4.40a) Therefore, with the aid of y =sin pi+ cos p k in the first equation in ( 4.40a ), the total angular velocity of the claw in the machine frame and referred to the yoke frame is given by the kinematic chain rule ( 4.25b ). We thereby obtain ro 30 = ~ sin P i + iJj + ( ~ cos p + li) k. (4.40b) The corresponding total angular acceleration may be found from ( 4.36 ). We observe in ( 4.40a) that y is fixed in frame 2; j is in frame 1; and k is in frame 0. Then the relative angular acceleration vectors derive from ( 4",
+ " The second problem concerns a speed control governor and will demonstrate three methods that use spherical coordinates in slightly different ways, one being the direct use of ( 4. 70) and ( 4. 71 ). The final illustration is an application of ( 4.46) and ( 4.48) to the motion of a point on a helicopter blade referred to a spherical reference frame. Motion Referred to a Moving Reference Frame and Relative Motion 279 Example 4.12. The relative angular velocity vectors for the general rotation of the manipulator claw of the robot shown in Fig. 4.7 are given in ( 4.40a ). Recall also that the length /( t) of the telescopic arm, as shown in Fig. 4.4, is a computer-controlled function of time. Find the absolute velocity and acceleration of point A on the claw referred to frame 2 = { 0; y, i', j} shown in Fig. 4.7. Solution. A few moments' reflection will reveal in Fig. 4. 7 that with y = e\" i' = e0 , and j = e.p frame 2 may be identified as the spherical reference frame t/t={O;e\"e0 ,e.p}\u00b7 It is seen that r=l(t),e={J(t), and \u00a2=r~.(t). Therefore, the absolute velocity and acceleration of point A on the manipulator claw may be read directly from (4.70) and (4.71). We find v A= ie, + lri sin {3 e.p + 1Pe8, a A= (i\"-IP2 -lri2 sin2 {J) e, + (2iri sin {J + 2/riP cos {J + Iii sin {3) e.p +UP+ 2iiJ -lri 2 sin {J cos {J) e0 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002746_0278364905060149-Figure23-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002746_0278364905060149-Figure23-1.png",
+ "caption": "Fig. 23. Reference points on surface plate and base platform.",
+ "texts": [
+ " If the base platform\u2019s position and orientation, which are represented in a coordinate system located on the surface plate, are measured while the machine is in process, the thermal and elastic deformations of the frame can be compensated independent of the structural and the material configurations of the machine base and the frame. In general, the three joints on the base platform of a tripodtype PKM shown in Figure 2(b) are located at regular intervals of 120 degrees. Moreover, two of the six joints on the base platform of a Hexapod-type PKM, shown in Figure 2(a), are closely located; thus, common PKMs have three joint supports mounting the mechanism. Thus, when three reference points are set on each joint support as shown in Figure 23, the position and orientation of the mechanism\u2019s base platform can be expressed by the coordinates of the reference points. Furthermore, the three distances among them, t1 \u2212 t3, represent the dimensions of the base platform. On the other hand, six reference points placed on the surface plate express its position and orientation. Consequently, the base platform\u2019s position and the orientation expressed in the coordinate system located on the surface plate are derived from the six distances among the reference points on both the joint supports and the surface plate, u1 \u2212 u6",
+ " In coordinate measuring machines, first a coordinate of the probe tip BPr , which is observed in the moving coordinate system \u2211 B , is calculated by the forward kinematics from the limb\u2019s lengths measured by the linear scale units. Secondly, the measured coordinate BPr is transformed to a coordinate B0Pr represented in the initial coordinate system \u2211 B0 by B0P r = B0P B + B0RB BP r. (7) In brief, all measured coordinates are rewritten in the initial coordinate system. at UNIVERSITY OF BRIGHTON on July 11, 2014ijr.sagepub.comDownloaded from Figure 26 depicts an example of the measurement method for the distance changes, u1 \u2212 u6, shown in Figure 23. The spherical joint is mounted on a joint support made of low thermal expansion cast iron. A Super-Invar rod is used as a spanner between the joint support and the surface plate. One end of the rod is connected to the surface plate by a flexure hinge. The other end is guided via a hole in a holder mounted on the joint support. A displacement sensor installed in the hole measures the displacement change in the rod end\u2019s surface in the longitudinal direction of the rod. The length of the rod is constant because no external force is applied to the rod"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003319_s0167-8922(08)71045-9-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003319_s0167-8922(08)71045-9-Figure2-1.png",
+ "caption": "Fig. 2 Bearing testing machine.",
+ "texts": [
+ " The inner race had a raceway groove, which the outer race did not have. The pitch circle diameter of the raceway groove of the inner race was 33.5 mm. The retainer was machined, and had a bore diameter of 25.2 mm and an outer diameter of 47 mm. were made of vacuum-degassed ASTM 52100 steel with hardness ranging from 61.4 to 62.4 HRC, while the material of the retainer was ASTM D2. The inner race, the ball and the outer race The bearing testing machine used in the The test bearing was attached to the rolling contact fatigue test is illustrated in Fig.2. bottom end of a spindle. downward axial load was statically applied to the bearing by means of a dead weight lever system. The test bearing was run under an axial load of 3.14 kN at a rotational speed of 660 rev/min in a mineral oil bath. contact pressure induced in the outer race was 5.64 GPa. considering the plastic deformation at the surface of the raceway track. minimum film thickness Ho to the composite surface roughness R was 0.21-0.27. film thickness Ho was calculated according to an The vertical and The maximum This value was obtained by The ratio of the The minimum roughness of the raceway track was measured after the test"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure10-1.png",
+ "caption": "Figure 10. Factors of the system with C3v symmetry: (a) in group-theoretical method; and (b) in canonical form III decomposition.",
+ "texts": [
+ " Now the eigenvalues (natural frequencies) of each subspace can be easily calculated. Whereas subspace V (3) is associated with double-repeating roots. The frequency found from subspace V (31) should be identically repeated in the set of answers for the original problem. Subspace V (1): 2 1 = k1/m and subspace V (3): 2 2 = 2 3 = (k1 + 3k2)/m Finally, it is concluded that two problems, each of which is of dimension one, are solved instead of a three-dimensional problem. The decomposed factors of this structure are shown in Figure 10, where the factors obtained above via the group-theoretical approach are shown in Figure 10(a), and the factors which result from the decomposition of canonical form III symmetry are presented in Figure 10(b). By comparing Figures 10(a) and (b) it can be seen that the efficiency of the group-theoretic approach is due to the decomposition of group-invariant subspace V (3) into orthogonal subspaces V (31) and V (32), or in better words, group-theoretical method can recognize the existence of the multi-repeating roots in a problem. Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm As another example, the symmetric dynamic system of Figure 11 is considered"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003075_bf02441586-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003075_bf02441586-Figure5-1.png",
+ "caption": "Fig. 5",
+ "texts": [
+ " (Sampling from a 37~ source for 20 s periods every 120 S at 22~ ambient ensures that the analyte is cooled to less than 27~ at the ChemFET input). The mode of operation of the system is self-explanatory; note that the reference electrode junction is situated immediately downstream of the ChemFET cell to eliminate spurious liquid-junction potentials, and that the inclusion of a three-way input tap is useful for rapidly priming the system during the initial setting-up procedure. The hardware is assembled on a 98 x 4 8 m m printed-circuit board, thus forming a small, robust 'remote sensor unit', shown in Fig. 5, with easy access to all fluid lines and incorporating a LED indicator to show when the valve is being actuated. This unit is mounted on to the end of a spring-cantilevered arm, which is then attached to the instrumentation trolley such that the remote sensor unit can be swivelled and rotated freely, and can be positioned rapidly and easily wherever required by the clinician, thus allowing flexible access for use in a wide variety of applications (e.g. at operating-table height, with cardiopulmonary bypass equipment (where the sampling site is close to the ground), at the bedside)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001423_s1350-4533(99)00095-8-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001423_s1350-4533(99)00095-8-Figure5-1.png",
+ "caption": "Fig. 5. The model of the lateral bands of the EDL (thickest black line segment) allows for slack in the distal portion of the central slip (serpentine portion of tendon shown in gray), caused by DIP flexion sufficient to tense the lateral bands. The lateral bands are assumed to bowstring from a",
+ "texts": [
+ " Keeping the number of parameters small helps insure that each can be estimated uniquely. The second term contributing to EDL excursion concerns the lateral bands, which divide from the EDL central slip, \u201cbowstring\u201d past the PIP joint without wrapping over the head of the first phalanx, and insert on the distal phalanx. These bands become taut only when the DIP joint is flexed enough to take the slack out of them. Once this point is reached, further flexion of the DIP joint can create slack in the terminus of the central slip, while further stretching the EDL muscle (Fig. 5). The contribution of the lateral bands to changing the length of the EDL depends on tautness (Eq. (6)). The top term reflects poses where the lateral bands are taut; the bottom term reflects poses where the lateral bands are slack. Given the approximate bilateral symmetry of these two tendons [10], one term is used to account for the effects of both the ulnar and radial lateral bands. The model predicts a non-linear relationship between PIP joint angle and EDL length when the lateral bands are taut, as does the model of An [10]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001061_s0021-9290(00)00032-4-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001061_s0021-9290(00)00032-4-Figure2-1.png",
+ "caption": "Fig. 2. Example of the two-step rotation compared with 3-1-2 sequence Cardan angles. XYZ is a reference Cartesian coordinate system, xyz is a segment \"xed coordinate system, y-axis represents the long axis of the segment.",
+ "texts": [
+ " Attitude AN(1): 903 rotation about z-axis (1)N(2): 903 rotation about x-axis (2)NAttitude B: 903 rotation about y-axis Rotation 2: Attitude AN(3)N Attitude B is long axis rotation#the axial rotation Attitude AN(3): long axis (y-axis) rotate 903 about X-axis of the reference frame (3)NAttitude B: 1803 axial rotation about the long axis Rotation 3: Attitude AN(4)N Attitude B is the axial rotation#the long axis rotation Attitude AN(4): 1803 axial rotation about long axis (4)NAttitude B: long axis (y-axis) rotate 903 about X-axis of the reference frame the long axis of the limb segment about a speci\"c axis passing through the proximal joint and perpendicular to the long axis of the limb segment, and the other is an axial rotation about the long axis (Fig. 1). The two-step rotation is apparently sequence independent. Using the two-step rotation method, the 3D rotation of the limb segment from one attitude to another in the physiological reachable range can be fully determined. To show this, an example is given below and compared with the rotations of Euler/Cardan angles in 3-1-2 sequence. In Fig. 2, XYZ is a reference Cartesian coordinate system, xyz denotes a segment \"xed Cartesian coordinate system and the y-axis represents the long axis of the segment. The segment \"xed frame xyz is assumed to be parallel to the reference coordinate system XYZ before rotation and is denoted as attitude A. In order to create a comparable attitude, \"rst let the segment (xyz frame) rotate from attitude A to attitude B by three ordered rotations, #903 each, following the 3-1-2 sequence used by Tupling and Pierrynowski (1987) as shown in the top of Fig. 2. The two-step rotation from attitude A to attitude B is shown in the middle and bottom of the \"gure. First, in the middle of Fig. 2, the long axis (y-axis) of the segment rotates 903 about the X-axis of the reference frame, then the segment axially rotates 1803 about the long axis (y-axis) of itself. If we change the order of the two rotations as shown in the bottom of Fig. 2, the same result can be obtained. More examples corresponding to other ordered rotations can be carried out by readers. The example shows that the long axis rotation can be uniquely determined by its initial and \"nal positions in the reference frame. Therefore, the segment rotation between any two attitudes can be uniquely described by the two-sequence-independent rotations. Determinations of the two rotations from two known attitudes are given in the following. In Fig. 3, the initial and \"nal positions of the long axis of the limb segment in the reference frame are represented by its unit vectors n 1 and n 2 , respectively",
+ " The gimbal-lock problem occurring in the axial rotation angles can also be resolved by dividing the full cycle of activity into a limited number of sections. If the full cycle was divided into two sections and the axial rotation angle from the \"rst initial attitude n 1 to the second initial attitude n@ 1 is / 1 , and from the second attitude to any attitude in the second section is /@ 1 , then the axial rotation angle from the \"rst initial attitude to any attitude in the second section can be calculated by the additive law as: / 2 \"/ 1 #/@ 1 . (B.1) In the graphic example (Fig. 2), the axial rotation from attitude (3) to attitude B reaches 1803 that is a gimballock point. If an attitude C between the two attitudes was recorded, the problem can be solved by selecting attitude C as the second initial attitude and dividing the full period of time into two sections, attitude (3) to attitude C and attitude C to attitude B (Fig. 6). In the case there may be more than one gimbal-lock point, the number of sections can be determined depending on how many gimbal-lock points involved in an activity, which can be pre-determined according to the activities to be investigated"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003974_tia.2005.863911-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003974_tia.2005.863911-Figure8-1.png",
+ "caption": "Fig. 8. Stator windings arrangement.",
+ "texts": [
+ " In the proposed system, the radial force detection block, as shown in Fig. 3, is added in Fig. 7. The radial forces F\u0302\u03b1 and F\u0302\u03b2 are calculated in the radial force detection block. These signals are amplified by a constant H , and subtracted from (1 + H)F \u2217 \u03b1 and (1 + H)F \u2217 \u03b2 . The four-pole windings are used as motor windings. These windings are connected to a motor driver operating indepen- dently from radial positioning. Thus, a motor driver can be commercial power lines, or general-purpose inverters. Fig. 8 shows the arrangement of stator windings in a cross section of a stator core of a three-phase bearingless induction motor. There are 24 slots in the stator core. The Nu4 and Nu2 show the four-pole motor and two-pole radial force winding conductors in the u phase, respectively. The two-pole winding conductor is made of two series and eight parallel 0.55 mm\u03c6 wires. The four-pole winding conductor is made of 5 series and 12 parallel 0.55 mm\u03c6 wires. The v-phase and w-phase windings are arranged symmetrically"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003394_tmag.1985.1064226-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003394_tmag.1985.1064226-Figure4-1.png",
+ "caption": "Fig. 4. Skmded-pole motor",
+ "texts": [],
+ "surrounding_texts": [
+ "respectively. After the discretization by finite elements, if o is assumed as a constant in the conducting regions, the above field equation holds:\n[SllA1+]c,~crfTI[AI= lRl[-agradt~l (3)\nwhere\nsij (NrN) = .~ .\n- ,. . ,,: ' , - . ,. c ~ ,,\n,,. , .,(, ,..- 1\n.~\n. . . . ,. . . . . . . I\n.. .... .\ni ... .\nFig. 3. {a) Exciting current of the relay (b) Eorces of the relay\nARpiicahon to the shaded-pole motor The method described is also applied to the solution of a four-pole shaded-pole motor. A cross section of the rnotm is shown In Fig.$. The main dimensions of the motor and the action of this type of motor have been described in [?I. All currents are assumed tx be adally direckd and the fielg eylyacjclns reduce to two-dimensional form. All the four pole-pitch of the machirie are analysed becguse of a non integral number o f bars per pole v,lth rotc?r. The Dirichlet boundary condition sahsfied by the finite element formulation is a t the outer surface of the stator. The finite element matrices are computed on the entire cross section of the machine.\nThe final equations must be solved at the rotating reference position of the rotor. The bar number is greater than the pole number for the squirrel cage motor, so the position of the rotor is' not important to the solution and an initial position is taker1 into account.\nThe iron core is laminated, its non saturated\npermeability is pi,=3000, B = p p , H , its conductivity in the axial direction is low and is assumed as zero. In this paper, only linear cas has been taken into account, but tile method described can also be applied to mrl linear cases by means of the multistep method or the equivalent permeability method.\nA finite element mesh of 2906 triangular elements of first order and a t o t a l of 1474 nodes to the entire cross section is shown in Fig.5. The sky-line storied technique is taken. There are 29 average elements per line.\nThe rotor currents for slip s with frequence sf, may be modelled by modification of rotor condu.chvity where f , is the su.pply freqwncy. In the rotor, the equation is\nV V w\nFig. 5 . Einite eiement mesh",
+ "2291\nREFERENCE\nA = A,sinCswt + rp), so\naiiAIht = jwasA = jwcr'A\n6' is equivalent conductivity with 6' = sa. The solution has been performed for slip values from 0 to 1. The equipotential plots are shown in Fig.6 at slip s= 1, and computed exciting currents versus the slip in Fig. 7. '\nCONCLUSION\nThe matrix method which ombines field equations with circuit equations has been, developed for calculating the performances of electromagnetic devices with specified terminal voltages and external impedances of electric circuit. This approach takes into account eddy current effects and creates a symmetric system with respect to the ones mentioned in the literature. I t has been verified using a 4-pOle shaded-pole motor and a electromagnetic relay in which the exciting current is computed. The agreement between computed and experimental results is satisfactory. This method should be useful in calculating electric devices such as relays and induction motors.\n1. M.VX. Chari, \"Finite element solution of the eddy current problem in magnetic structures\", IEEE Trans. Power App. Sys. Vol. PAS-93, 1973. 2. T. Nakata, N. Takahaski, \"Direct finite element analysis of flux and current distributions under specified conditions\", IEEE Trans. Mag., Vol. MAG-18, N02, pp325-330, 1982. 3. S. Williamson, J.W. Ralph, \"Finite element analysis of an induction motor fed from a-constant-voltage source\", Proc. IEE,Vo1.130, Pt.B. N*l,ppt8-24, 1983. 4. P.G. Potter, GX. Cambrell, \"A combined finite element and loop analysis for non-lineary intkracting magnetic fields and circuits\", IEEE Trans. Mag., Vol. MAG- 19, N\"6, ~ ~ 2 3 5 2 - 2 3 5 5 , 1983. 5. M. Ito, N. Fujimoto, H. Okuda, N. Takaski, T. Miyata, \"Analytical model for magnetic field analysis of induction mobr performance\", IEEE Trans. Power App.\n6. A. Konrad, \"The numerical solution of steady-state skin effect problems - an integrodifferential approach\", IEEE Trans. Mag. Vol. MAG- 17, 1981 7. R. Perret, \"Contribution a 1'8tude des moteurs mOnOphaSeS a bobines Ocrans saturk\", These d'Etat, Grenoble, 1974.\nSYS, VOl. PAS-100, N O 1 1, ~~4582-4550 , 1982."
+ ]
+ },
+ {
+ "image_filename": "designv11_6_0002579_robot.1997.606743-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002579_robot.1997.606743-Figure6-1.png",
+ "caption": "Figure 6: 3R free-joint manipulator",
+ "texts": [
+ " We can construct a control of the system such as a free-joint manipulator which has no stable equilibrium points, while Baillieul consider a stabilization to an equilibrium point by energy dissipa- tion. About the subsequent procedure to the convergence to the desired manifold, that is, stopping at the destination, the method was provided in our previous work[l]. In the next section, we show another example for a 3R free-joint manipulator. 4 3R free-joint manipulator 4.1 Averaging the manipulator We consider a 3R free-joint manipulator whose first joint is only actuated and others axe free as shown in Fig. 6. We consider the manipulator resides in the horizontal plane and the mass, the inertia momentum, the length of ith link and the distance from the i th joint to the center of mass of the ith link are denoted by mi, 4, l;, and si , respectively. The dynamics is given by 8) (16) where 2 A1 = 11 4- m1sl2 + mdx2 + m3dl , A2 = I2 + m 2 ~ 2 ~ + m31z2, A3 = 13 + m 3 ~ 3 ~ , B21 = m31112 + m2l1s2, B31 = m311s3, B32 = m31m and cZ1 = cos(& - SI), ~ 3 1 = C O S ( & - el), ~ 3 2 = C O S ( ~ S - & ) , s21 = sin(02-01), a "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001509_978-1-4615-3176-0_10-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001509_978-1-4615-3176-0_10-Figure1-1.png",
+ "caption": "Figure 1: A rigid-body model of a falling cat",
+ "texts": [
+ " Thus, a reasonable model of a falling cat is consisted of the upper body and the lower body, both treated as rigid, coupled to each other by either a ball-in-socket joint or a universal joint. If modeled by a ball-in-socket joint, the upper body would have three degrees of freedom (dof) relative to the lower body, and 2 dof otherwise. In this paper, we will consider both models as a ball-in-socket joint model would give us a system with 6 states and 3 control inputs and universal-joint model a system with 5 states and 2 control inputs. 2.1 A Ball-in-socket Joint Model Consider the system shown in Figure 1. The coordinate frames Co, C1 and C2 are called, respectively, the inertial reference frame, the body fixed frame to body-1 (the upper body) and the body fixed frame to body-2 (the lower body). We assume that the ori gins of the body frames coincide with the mass centers of the respective bodies. For body i = 1,2, we denote by (ri' Ai) E ~ x SO(3) the position and orientation of frame Ci relative to the inertial frame Co, and also by r E ~ the position vector of the mass center of the whole system"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure6-1.png",
+ "caption": "Fig. 6. Generation of worm by plunging disk.",
+ "texts": [
+ " In case of a misaligned gear drive with imaginary rigid teeth, the contact ratio due to misalignment is one only. The desired parabolic function of transmission errors is obtained by plunging of the disk that generates the pro\u00aele crowned worm surface R 1 w . Thus, the worm thread surface will be crowned in the longitudinal direction also. Henceforth we will use designation R 1 w for the pro\u00aele crowned worm surface and R 2 w for the double-crowned worm surface (crowned in pro\u00aele and longitudinal directions). Drawings of Fig. 6 illustrate how the longitudinal crowning of worm thread surface Rw is accomplished. Fig. 6(b) shows the installment of a disk provided with surface Rc for generation of worm thread surface. The axes of the disk and the worm are crossed and form angle cc kw, where kw is the lead angle of the worm at the surface Rw middle point Ow. The current shortest distance Ec wc (Fig. 6(a)) between the axes of the worm and the disk is varied in the process of worm generation. The disk (with coordinate system Sc) is hold at rest and the worm performs a screw motion about its axis zw. During this motion, the disk is plunged and the current shortest distance Ec wc is executed as Ec wc Eo \u00ff apll2 w: 17 Here, Eo is the initial shortest distance; lw the axial displacement of the worm measured from the middle point Ow; apl the parabola coe cient of the parabolic plunging function Eo \u00ff Ec wc apll2 w: 18 Parameter wc indicates the angle of rotation of the worm in its screw motion (Fig. 6(c)). Disk surface Rc is conjugated to the pro\u00aele crowned worm thread surface R 1 w . This means that Rc will generate R 1 w if only screw motion is provided in the process of worm generation. Double crowned worm surface R 2 w is generated by Rc if plunging of Rc is executed in addition to the screw motion. Surface R 2 w is determined as the envelope to family of surfaces Rc that is generated in coordinate system Sw rigidly connected to the worm. The main goal of simulation of meshing is to determine the shift of the bearing contact and transmission errors caused by gear drive misalignment"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000548_s0584-8547(99)00038-5-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000548_s0584-8547(99)00038-5-Figure2-1.png",
+ "caption": "Fig. 2. Schematic diagram of the incorporation of the graphite \u017d . \u017d . \u017d .tube in the flow system: A sample in; B graphite tube; C \u017d .gaskets; and D sample out.",
+ "texts": [
+ " Schematic diagram of the flow system: A sample; B \u017d . \u017d . \u017d .PTFE tubing; C peristaltic pump; D plexiglass closure; E \u017d . \u017d . \u017d . \u017d .graphite tube; F contact to tube; G cell; H membrane; I \u017d y1 . \u017d . \u017d .counter space 1 mol l HNO ; J counter electrode; K3 \u017d . \u017d .reference electrode; L potentiostat; and M waste. fect flow of the solution along the inner walls of the graphite tube and for the metal deposition only in the central part of the tube. The incorporation of the graphite tube is given in Fig. 2 in detail. The graphite tube is placed on a plexiglass rod, which forms part of the flow-through cell. At the opposite end of the graphite tube a closure from plexiglass with a gasket is inserted. The whole space with the working electrode was washed for 2 min with doubly-distilled water, and then the sample solution was pumped. After deposition the graphite tube was rinsed with doubly-distilled water for 3]5 min, removed from the cell and dried by means of an infra-lamp. Finally it was placed into the graphite furnace for measurement according to the temperature pro\u017d "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000418_s1474-6670(17)40039-5-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000418_s1474-6670(17)40039-5-Figure2-1.png",
+ "caption": "Fig. 2. The free-body diagram of a helicopter in flight",
+ "texts": [
+ " The state is defined as x = [pT VT RT wTV E ~3 X ~3 X 50(3) X ~3 where P and V are the position and velocity vectors of center of mass in spatial coordinates, R is the rotation matrix of the body axes relative to the spatial axes, and the body angular velocity vector is represented by w. The controls are u = [OM OT a bV E ~4 where OM, OT, a and b are the main rotor collective pitch, tail rotor collective pitch , longitudinal cyclic pitch and lateral cyclic pitch , respectively. The state equation consists of the transla tional and rotational kinematic and dynamic equations: where b[ = [0 0 IV and g is the gravitational constant. As shown in Figure 2, J b and T b are the resultant force and torque acting on the body, respectively. Both force and torque are functions of the controls, u. For details, please refer to (Lee et al., August 1993). 3. Hybrid Control Formulation This section describes the hybrid control problem of integrating the continuous con trol laws and system dynamics with the dis crete planning and decision making. In case of the helicopter , the hybrid system design has to consider multiple, sometimes conflict ing objectives such as safety, efficiency, accu racy and reliability of operation"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003219_iros.1992.594551-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003219_iros.1992.594551-Figure4-1.png",
+ "caption": "Fig. 4. Mechanism to be used for excavation. From 1161.",
+ "texts": [
+ " The cost of this simplification is that the selected point in the action space specifies only one dig and at most we can be sure that we have picked the best dig on a per dig basis but not necessarily the one that will provide the most gain over the entire task. Neither can we be certain that the search will escape local extrema. Hence, although we have avoided the issue of a very large search space with complex obstacles to avoid, the second issue of search remains. 111. THE APPROACH In order to provide an intuitive understanding of the proposed approach, let us consider an extended example in a twodimensional world. Fig. 3 Fig. 3 shows a terrain that must be excavated and Fig. 4 shows the conventional version of a mechanism that is to be used. This sort of device is commonly called a \u201cbucket loader\u201d or a \u201cfront-end loader\u201d and can be automated. The loader is M completely excavate the pile, without intruding below the surface of the ground. In this example, we will show how geometrk and force constraints are imposed on the acuon space (a, d , h) from Fig. 2. Force constraints are refined through force feedback data obtained during experimentation. The constrained volume is then searched to select a dig that maximizes the amount of soil obtained",
+ " We will model the excavator as a P-R-R manipulator shown in Fig. 5. Given a candidate dig, that is a trajectory for the bucket tip to follow, a standard inverse kinematics method is used to find the corresponding joint displacements (dl , 02, e3). A candidate dig may fail this constraint if it is required that the excavator reach outside its workspace (exceeds joint limits) or if in the course of the dig, one or more of the links are required to interpenetrate the terrain. The composite constraint surface due to the terrain in Fig. 3 and the excavator in Fig. 4, is shown in Fig. 6. The surface represents the boundary between the reachable and nonreachable digs- all points below the surface represent digs that meet the reachability constraint. Volume Constraint: Since the excavator bucket can only hold a volume Vmax, then an (a, d, h) triplet should not excavate more than this amount of soil. This gives us a further basis on which we can limit the set of feasible digs. This constraint is shown in Fig. 7. Shaping Constraint: This constraint is given by the goal state of the terrain",
+ " $ is also called the angle of internal friction and is directly visible as the angle of repose of a pile of dry, uncompacted granular material like sand and sugar. So far, in this section we have said that if the soil properties (density, angle of internal friction, cohesion) are known, it is possible to get order of magnitude estimates of the resistance force encountered for the type of digging motions that have been proposed. The action space can now be further constrained based on whether or not it is possible for the robot to generate the required forces for perform a candidate dig. Lets say that the excavator in Fig. 4 can develop a maximum of 1000 units of force at the end effector. Also, lets assume that the soil properties are y= 20, @ = 30, c = 5. The constraint surface due to force limitation, given the terrain of Fig. 3, can be seen in Fig. 10. C. Search for an r r O p t i d Dig It remains now to search this space for a point that optimizes a cost function- at least up to an acceptable threshold of the maximum expected. We might note some properties of this optimization problem: the search space is large"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003364_0020-7403(88)90076-8-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003364_0020-7403(88)90076-8-Figure3-1.png",
+ "caption": "FIG. 3. Normal tractions, frictionless contact, v = 0.3.",
+ "texts": [
+ " (14) n= - ( S - 1) This renders the problem determinate, since there are now 2S + 2 equations in as many unknowns--the 2 S - 1 ordinates of pressure P, , D (a measure of the rigid body normal approach), A (a measure of the contact width) and the eccentricity e. It should be noted that from the symmetry of this configuration we expect that e will be zero. The equations are linear and are thus readily solved using a computer library routine. Some sample results obtained with S = I0 and v = 0.3 are shown in Fig. 3. For large tyre thicknesses, the normal pressure distribution approaches that of Hertz [8] for contact between a rigid cylinder and an elastic half-plane. As the tyre thickness is reduced, the contact width decreases and there is a corresponding increase in the peak pressure. The pressure distribution, however, remains approximately parabolic. At very small strip thicknesses the contact patch becomes very small, as the configuration now approximates that of the contact of two rigid cylinders, where point contact applies"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002677_rob.4620070207-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002677_rob.4620070207-Figure2-1.png",
+ "caption": "Figure 2. The PUMA robot.",
+ "texts": [
+ " Then use the relations (11) to detect the existence of possible supplementary eliminations and the relation (27), (29) to detect the particular regrouping of the parameters of link j , for j = 1, . . . , r2. This will concern the translational links between r l and r2, if the axes of the joints between r l and r2 are parallel or perpendicular the relations (34) and (35) can be used. We have developed a program which calculates automatically steps 1 and 2 and Xi and fi needed in step 3.213rr In the following example we get the minimum inertial parameters of the six rotational joint of the 560 PUMA robot. (Fig. 2). The geometric parameters of the robot are given in Table 1. Step (1) the parameters having no effect on the dynamic model are: Step (2) using relation (31) for j = n, . . . , 2 we get: Khalil, Bennis, and Gautier: Minimum Inertial Parameters of Robots 237 j = 6 : The minimum parameters of link 6 are: XXR6, m6, XZ,, Y&, zz6, MX6, M y6. j = 5 : XXRS = XX5 + YY, - YY5 XXR4 = XX4 + Y Y 5 ZZR4 = ZZ4 + YY5 MYR4 = MY, - M Z s 238 Journal of Robotic Systems - 1990 The minimum parameters of link 5 are: XXR5, XY5, X Z 5 , YZ,, ZZR5, MX5, j = 4 : MYR5"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000774_(sici)1097-4628(19961107)62:6<875::aid-app3>3.0.co;2-m-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000774_(sici)1097-4628(19961107)62:6<875::aid-app3>3.0.co;2-m-Figure3-1.png",
+ "caption": "Figure 3 troscopy. Experimental setup used for UV-visible spec-",
+ "texts": [
+ " This solution was used to load the microcapsules with Au-tagged HRP. Gold, being electron dense, can be easily observed within the PPy capsules using the TEM. The microcapsules used for these studies were prepared by the purely chemical method. Monitoring Enzyme Activity We have encapsulated five enzymes and one chemical catalytic system within microcapsules prepared via the electrochemical/chemical method described above. UV-visible spectroscopy was used to assay the activity of the encapsulated enzymes. The experimental setup used is shown in Figure 3. The enzyme-loaded microcapsule array is inserted (using the glass rod) into a cuvette (3 mL) that contains the substrate for the enzyme and the enzyme assay chemistry (see below). The cuvette is present in the sample chamber of a Hitachi U-3501 UV-vis spectrometer. A magnetic stir bar is used to stir the solution in the cuvette. Prior to the monitoring of the enzyme activity, the enzyme-loaded microcapsule array was immersed in the buffer solution a t 4\u00b0C. The solution was stirred for a period of 2 days"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001521_iros.1994.407377-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001521_iros.1994.407377-Figure1-1.png",
+ "caption": "Figure 1: a) Path planned by means of Eq. (1) at k = 60, b) Logarithmic representation of concentration distribution at k = 60",
+ "texts": [
+ " This algorithm updates the distribution function ~ k ; ~ for each time step k by means of simple mathematical operations between M (4 or 8) neighboring cells of T . If k is large enough and R\u2018 and 6R\u2019 are fixed, the function converges to its equilibrium state umir. um;r shows a single peak at TG with a monotonous slope leading to any point T in the workspace (Fig. l(b)). The path from each arbitrary starting point TS to TG is computed by following the gradient of um;r. Interpolation methods have also been utilized to obtain smooth paths (Fig. 1 (a)). As addressed in [7], the diffusion equation algorithm can be directly implemented on a parallel processor system. However, even a sequential implementation meets real time requirements. 2.1 Extended Diffusion Process The diffusion planner in its basic form can be directly applied to path planning for real mobile robots. Robots with circular or quadratic shapes are assumed to be reduced to a point if we apply the principle of obstacle grciwing, i.e. expanding the obstacles by the radius of the robot"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002731_j.ijmachtools.2004.03.005-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002731_j.ijmachtools.2004.03.005-Figure3-1.png",
+ "caption": "Fig. 3. Probes: (a) a straight probe and (b) a bent probe.",
+ "texts": [
+ " The accurate virtual CMM model simulates CMM operation and its measurement process with haptic perception. The CMM off-line programming model does all inspection planning tasks, including all high and low levels inspection planning mentioned above. Fig. 2 shows the HVCMM system working flowchart. The research in this paper focuses on low-level path planning for CMM. We assume that the part is in a given setup and a specific probe has been selected in a specific orientation. A straight probe, shown in Fig. 3(a), is normally attached to the CMM ram, which is much longer than the probe and aligned with its axis. We consider the whole ram/probe assembly as forming the straight probe and make no distinction between the two. For complex parts, a bent probe as shown in Fig. 3(b) is needed to measure some features such as holes at different angles. To position the points to be probed of a part, it is required to view the part\u2019s CAD model or the whole scene, including the part and the HVCMM, from different points of view. In the HVCMM system, the scene can be rotated, translated, and zoomed. There is no coordinate compensation for the rotation and translation of the scene. Fig. 4(a) and (b) show the original and rotated scene, respectively. It is very easy to do it by pressing and holding the button on the stylus of the haptic device",
+ " The following sections describe the proposed methods for collision (or contact) detection and contact force feedback. The collision detection is an important subject for dimensional inspection with CMM. As the HVCMM system is used in this paper for the inspection path planning, the operator is responsible for deciding the zones to be inspected and the positions of points to be probed. Therefore, it is much easier to generate collision-free probe paths. For a contact measurement, the part might collide with the tip, the stylus and the body of a probe [17]. In this paper, a straight probe as shown in Fig. 3 is mainly considered. The diameter of the tip is larger than that of the stylus. Collision with the tip happens when any surface of the part is in the traversing trajectory of the probe, such as the path from A to B shown in Fig. 5(a). Collision with the stylus happens when probing a point near or under a cantilever as shown in Fig. 5(b). Collision with the body of a probe happens when probing points under a cantilever as shown in Fig. 5(c) and the measuring stylus is not long enough when inspecting a narrow slot as shown in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001656_1.1330743-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001656_1.1330743-Figure2-1.png",
+ "caption": "Fig. 2 Analytical model of a tri-pad contact slider",
+ "texts": [
+ " Furthermore, the design conditions of the contact sliders and the disk surfaces both for perfect contact sliding and wear durability are discussed. Figure 1 shows a typical geometry of a tri-pad slider which has two front air bearing surfaces and one rear air bearing surface with a contact pad. Note that the figure illustrates an example of the tri-pad slider and one can design freely the air bearing surfaces and the contact pad according to the design conditions discussed in this paper. An analytical model of the tri-pad contact slider and the surface of the disk which was utilized in this analysis is shown in Fig. 2 @13#. The tri-pad contact slider is modeled as a rectangle with length a and height b. The slider suspension system is represented as the normal spring stiffness k, the angular spring stiffness ku , and the damping coefficients c and cu . The air bearing effects are represented by two lumped linear springs ~k f and kr! and the dampers ~c f and cr!, which are distant from the center of the mass of the slider by d f and dr , respectively. Although the air bearing has nonlinear stiffness, it was not taken into account for the sake of simplicity"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003210_j.conengprac.2005.06.005-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003210_j.conengprac.2005.06.005-Figure3-1.png",
+ "caption": "Fig. 3. Sketch of a SCARA robot following a contour.",
+ "texts": [
+ " The contact is achieved by means of a proper probe endowed with a ball bearing with an 8mm diameter whose aim is reducing tangential friction forces that may arise from the contact with the piece (see Fig. 2). The PC-based controller is based on a QNX4 real time operating system and the control algorithms were written in C/C++ language. Acquisition and control were performed at a frequency of 1 kHz. The task to be performed by the end-effector of the manipulator is to track the contour of an unknown (planar) object with a given reference tangential velocity and by applying a given force to the object in the normal direction. With reference to Fig. 3, frame (0) refers to the robot base, while the task frame \u00f0T\u00de has its origin on the robot end-effector, its n-axis directed along the normal of the piece contour and its t-axis along its tangent; W is the angle between n-axis and x-axis of frame (0). Let Q \u00bc \u00bdq1; q2 T be the vector of joint positions and _Q; \u20acQ its first and second time derivatives, respectively. Since a suitable belt transmission keeps the end-effector with constant orientation with respect to the absolute frame, the force measurements are directly available in frame (0)",
+ " Note that these testbed workpieces have significant dimensions with respect to the manipulator workspace (see Fig. 5, where the position of the pieces tracked in all the experiments presented in the paper is shown). Both pieces have been tracked counterclockwise with a constant normal reference force of 20N and a tangential velocity of 8mm/s for the disc and 10mm/s for the wooden object. Control law (3) has been used. The robot configuration was such that the joint angle q2 between the second and the first link (see Fig. 3) always maintains a positive value during the contour task. The PID gains have been selected through an extensive trialand-error procedure in order to guarantee that the contact of the probe with the workpiece is not lost because either of the excessive increase of force oscillations or of the excessive normal force error occurring when joint friction torque changes its signs at the motor velocity inversion. As a result of this procedure, the derivative action of the force PID controller was not adopted, actually, as it will be discussed in Section 4"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.2-1.png",
+ "caption": "Figure 3.2. Direction angles of a unit vector n, and a change of basis.",
+ "texts": [
+ "96) to obtain (3.99) And similarly, reversing the roles of the primed and unprimed sets and using (3.97) while retaining the definition (3.96), we have also (3.100) Either of the transformation rules (3.99) and (3.100) is called a change of basis. The same thing may be seen in more geometrical terms by our recalling that any unit vector n, say, may be expressed in terms of the three cosines of the direction angles 11.1 that it makes with the familiar orthonormal basis direc tions i1 at a point Q, as shown in Fig. 3.2a. Namely, n =cos 11.1 i1 . If we write cos(n, i1 ) for the cosine of the angle 11.1 between n and the i1 direction and agree, as mentioned above, to extend the summation rule to terms in the cuneiform brackets, then n may be written more conveniently as n = Finite Rigid Body Displacements 177 cos (a) Voltage and current 90\u00b0 out of phase. 79 derivations will be omitted here, but the results are stated in the suc ceeding paragraphs. For constant-frequency cases where the voltage and current waveforms are sinusoidal, phasors can be used as a convenient means to display the phase relationship between voltage and current",
+ " For motoring operation, the values of power factor are between 0 and 1.0. A nega tive value of power factor signifies induction generator operation. Usually, power factor, like efficiency, is expressed as a percentage value, for example, 90%, rather than the per-unit value, 0.9. It is useful to define two additional terms for subsequent discus sions. The apparent power, PA , is (5.3) and the reactive volt-amperes, V AR, are V AR = VI sin() (5.4) For most motor calculations the term KV AR, kilovolt-amperes, is I (c) Voltage and current phasors for Figure 5.2(b). Power Factor 81 more convenient to use. The relationship between the three quantities defined by (5.2), (5.3), and (5.4) can be displayed in a phasor diagram shown in Fig. 5.4. Now, having defined the various components, let us consider their effects on energy consumption. The real power, as previously noted, is delivered to the motor as electrical power and is converted by the motor to mechanical power which is delivered to the load plus losses which escape as heat. This power has to be supplied by the power system and, therefore, some form of fuel-oil, coal, gas, nuclear, etc"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure2.8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure2.8-1.png",
+ "caption": "Figure 2.8. Composition of successive infinitesimal rotations about concurrent axes.",
+ "texts": [
+ " Therefore, in light of the character of finite rotations, it is of interest to verify that successive infinitesimal rotations of a rigid body about concurrent axes, independently of their order of execution, may be added vectorially to form a single equivalent infinitesimal rotation about another concurrent line. To establish this result, let d 1 and d2 denote two displacements due to consecutive infinitesimal rotations through angles A(} 1 and .182 about the respective concurrent axes a 1 and a2 through a point fixed at 0, as shown in Fig. 2.8a. Then, in view of (2. 18 ), the corresponding infinitesimal dis placements given by (2.13) may be written as d 1 =A9 1 xx, d2 = L19 2 X X1 = .192 X X+ L19 2 X (,19 1 X X), (2.20a) (2.20b) Kinematics of Rigid Body Motion 97 where x 1 = x + d1 is the position vector of a particle P after the first rotation from its initial place at x. The total displacement is d = d1 + d2 \u2022 Now, starting from the same initial position x and using identical rotations but performed with AIJ2 followed by AIJ 1 , as shown in Fig. 2.8b, we see with (2.18) and (2.13) that the corresponding infinitesimal displacement vectors are given by a!= L192 X X, a2 = AOI X XI= AOI X X+ AOI X (L192 X x), (2.21a) (2.21b) wherein X I = X + a I is the position vector of p after the first rotation, and now a= a 1 + a2 defines the total displacement. Upon discarding terms of order larger than the first in AIJ 1 and AIJ2 in (2.20b) and (2.21b), which is consistent with our earlier approximation m (2.18), we find and Therefore, regardless of the order of the rotations, the total displacement, a= a 1 + a2 = d2 + d 1 = d, is the same; and, With the aid Of the foregoing relations, it may be written as Consequently, there exists independently of the order of the rotations an equivalent infinitesimal rotation (2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001200_jjap.38.5660-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001200_jjap.38.5660-Figure2-1.png",
+ "caption": "Fig. 2. Schematic alignment structure of SSFLC: the molecules on the chevron interface are parallel to each other and to the substrate surface.",
+ "texts": [
+ " (2) represent nonpolar anchoring and symmetric functions of the azimuthal angle of the c-director (\u03c6) about \u00b1\u03c0 /2, and the third term represents polar anchoring and breaks the symmetry mentioned above. If the orientation of the LC molecules is the uniform structure, p0= pd . If it is defined that fS = f 0 s 1(Y )+ f d s 1(Y \u2212 d), (3) the total free energy of a conventional SSFLC cell (FSS), whose effective area is A, at the quiescent condition is given by FSS = \u222b A 0 \u222b d 0 ( felas + fS)dY d A, (4) where we assume that the orientation of the LC directors is homogeneous at the chevron interface as shown in Fig. 2. Furthermore, if we assume that the two substrate surfaces are equally treated, the orientation of the LC molecules is symmetric about the chevron interface and A = 1 m2, eq. (4) can be expressed as FSS = 2 \u222b d/2 0 ( felas + fS)dY, (5) where \u03b4 > 0 in the C2 structure. We also assume that in Y = 0 to Y = d/2, \u03c6(Y ) =\u03c6s + ( d\u03c6 dY ) Y =\u03c6s + ( \u03c6c \u2212 \u03c6s d/2 ) Y, (6) where \u03c6s and \u03c6c are the azimuthal angle of the c-director of the FLC molecules on the substrate surface and chevron interface, respectively, and are expressed as sin\u03c6s = tan \u03b4 tan \u03b8 + sin \u03b2 sin \u03b8 cos \u03b4, (7) sin\u03c6c = tan \u03b4 tan \u03b8, (8) where \u03b8 is the cone or tilt angle"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002362_itsc.2003.1252673-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002362_itsc.2003.1252673-Figure3-1.png",
+ "caption": "Figure 3 Vehicle model",
+ "texts": [],
+ "surrounding_texts": [
+ "1. Introduction An automated parallel parking strategy for a vehicle-like robot is presented. This study i s part ofthc research project in t,hc development of the autonomous vehicle control. I\u2019arallel parking is difficult for human driver especially Ibr beginners. Therefore. this type or problems altracts a great deal of attention from the research community. This research is derived from the study ofmotion-planning ofrobots. There exists many algorithms in robot motion planning and they were difficult to apply those algorithms into fourwheels vehicle parking cases. The research on this topic can be clissifird into two groups: I-stabilization of the vehicle to a point by means o f feedback state; 2 - planning a feasiblc path to reach a point and following the path. I n the lormer category, Yasunobu and Murai [I] have proposcd a controllcr based on human experience to develop a hierarchical fuzzy control and predictive f u v y control for vehicle parking. The vehicle i s controlled moving point by point. That algorithm generates the mancuvering path point by point from the human knowledge base in the predictive fuzzy controller. Researchcn 1101 only concerning the classical four wheels vehicle. trailer vehicle are also considered. Jenkin and Yuhas 121 have reported a simplified neural network controller by decomposition. The neural controller i s decomposed by subtasks. The neural controller is trained based on the kinematics data, however the decomposed neural network require less training time thus i t has simplified the training process. Kin,jo. Wang and Yamamoto [3] have used Genetic Algorithm (GA) to o p l i m k neural Contmller for controlling trailer truck. Initially theneural controller i s produced randomly and GA changes the weighting af the controller to a suitable d u e . The algorithms discussed above are based on the kinematics data to formulate intelligent controllers.\nFor the path planning category. Paromtchik and Laugier 141 presented an approach to parallel parking for a nonholonomic vehicle. In thatapproach. a parking space i s scanned before the vehicle moves backward into i ts parking bay. The vehicle follows a sinusoidal path in backward motion. while the fbrward motion is along a straight line withoot sideways displacement. I n this approach. the possible collision during reverse betwecn thc vehicle and thc longitudinal bnundar) ofthe parking space i s not discussed. Murray and Sastry [ 5 ] worked on steering a nonholonomic system between arbitrary points by means of sinusoids.\nAutomatic parallel parking involves inany problems. such as recognition of driving circumstances. maneuvering path planning. communication and vehicle control. This paper focuses on the maneuvering path planning. \u2018The system works in three phases. I n scanning phases: the parking circumstance, is scanned by infrared srnsors after the parking command is activated. I t then gucs to ncxt phasr. starling phase. after a\nsuitable parking space has been detected. The maneuvering path i s also produced according to the scanned information. The robots movrs backward to the edge ofthr parking position and begins its parking strategy. In order to avoid potential collision. the robot starts at thc suitable position which depends on different dimension of parking space. In the final phase. inaneuvertrackiiig phase. the robot followsthc path 10 a desired parking posi!ion. The parameters ofthe maneuvering path have beenproduced off-line. A database has been built for different ~ i r ~ ~ m s t a n ~ e such as the longitudinal and latrral\ndimension ofparking space, thedimension ofvehicle-like robot. i ts specification ofthe stcrring angle (maximum turning angle) and lateral displacement from the aside car.",
+ "2. Car Modelling A four-wheeled vehicle-like robot is considered. The location of the vehicle reference to the coordinate system is denoted as (x .y ,e ) , where yare the coordinates of the midpoint of the robot's back wheel axisand e is the orientation of vehicle that the angle relative to its parallel position. Therefore, the motion ofvehicle in time-varying can be described as the followings:\ndx -= vcosacose di\n- = Y c o m i n 6 dr dB m i n a dr L where' a i s the steering angle, v is the velocity of the vehicle and L is distance between two wheel axis. Equations ( I ) are valid for the robot moves in flat ground in slow speed and there is no significant slippage. In planar motions, the robot subject to a constraint which is the limits of the steering angle a, -% 3.0.co;2-i-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001575_1097-4628(20001121)78:8<1566::aid-app140>3.0.co;2-i-Figure4-1.png",
+ "caption": "Figure 4 Three-dimensional tire model for implicit FEA.",
+ "texts": [
+ " Assuming a deformation during manufacturing process is purely due to pantographic action, the angle and spacing of REBAR in the cured tire can be obtained as follows: a 5 Fr9sin b9 r sin b Ga9, b 5 cos21F r cos b9 r9~1 1 \u00ab!G (1) where a, b, r, and \u00ab are spacing, angle, radius, and elongation factor of fiber reinforcements after lift, respectively. Also, a9, b9, and r9 are spacing, angle, and radius on a tire-building drum. After a tire is mounted on a rim, an inflation pressure of 200 kPa is applied to the axisymmetric tire FE model. Figure 4 shows a three-dimensional FE tire model that can be generated based on the inflated results with the symmetric model generation, and the symmetric results are transferred to a threedimensional format with capability of ABAQUS/ Standard. A pavement is modeled as a rigid element. The steady-state transport analysis capability can be formulated with a moving reference frame technique, so a mesh needs only to be refined in a contact region, as shown in Figure 4. This model has 5976 nodes and 4464 elements. On the other hand, a fine mesh is required in circumferential direction for the explicit finite element technique, as mentioned later.3 Before a cornering simulation of a tire, braking and driving simulations are conducted with slip angle of 0\u00b0 in order to determine a free rolling radius of a tire. In the steady-state rolling simulation based on moving reference frame tech- nique, angular velocity of a tire is required to synchronize with travel velocity"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003002_0021-9797(84)90503-4-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003002_0021-9797(84)90503-4-Figure1-1.png",
+ "caption": "FIG. 1. Schema of the apparatus, m, Stainless steel; [~, Teflon; [], copper; ~, rubber.",
+ "texts": [
+ "4 dyn/cm K at 30\u00b0C below the minimum, to +0.2 dyn/cm K 30\u00b0C above the minimum. The n-hexanol and the n-heptanol (quality puriss) were provided by Fluka. The n-nonanol was purified by distillation under vacuum by Professor R. Vochten. 261 Journal of Colloid and Interface Science, Vol. 98, No. 1, March 1984 The water used is bidistilled (the first distillation being done in presence of KMnO4). In order to create zones at the surface at different temperatures and to observe movements between them, we used the simple setup described in Fig. 1. A Pyrex container Ct (diameter 1 cm, depth 1 cm) contains the solution to be studied. The latter is maintained at the temperature T~ by circulating water in the container C2. A double-wall Pyrex lid filled with water at T3 (/'3 > Tt and T2) prevents air currents from inducing movements at the surface and also prevents condensation of the vapor emitted by the solution. Through the orifice E in the lid, talc powder can be blown on to the liquid surface with an adapted needle. Another circular orifice (diameter 1 cm) allows us to adjust the heating system (or the cooling). It consists of a copper disk (diameter 3 cm, thickness 1 mm) welded to a vertical inox tube (diameter 1 cm) in which water circulates at the temperature T2. The steady temperature is attained in 2 min, this has been checked by using a Pt resistor. A Teflon piece (D) (0.5 mm thick) insulates the bottom and the lateral parts of the copper disk. Small orifices (F) (diameter 1.5 mm) in the copper disk and the Teflon permit the liquid to flow. The whole setup represented in Fig. 1 is placed on the carriage of a profile projector (Nikon Model 6) under a telecentric objective giving a magnification of 10. The device described above can be lit either by the side or from below. 0021-9797/84 $3.00 Copyright \u00a9 1984 by Academic Press, Inc. All rights of reproduction in any form reserved. 262 NOTES NOTES 2 6 3 The movements at the surface are made visible by test bodies. We used either talc powder or glass beads (Type Glaverbel Microcel Type M35, density 0.35, diameter 1/10 mm) the density of which is lower than that of the solution. 3. RESULTS Experiments were carried out with the three prepared solutions by imposing a temperature gradient in the region where the temperature is lower than the one for which the surface tension is minimum; a temperature gradient in the region above this minimum. Each gradient has been applied successively in both senses: for the same difference AT, T2 > TI, then TI > T2. The liquid height in the trough (CI, Fig. 1) was nearly 1 cm. The copper plate was placed at nearly 1 mm (or less) under the free liquid surface. The results concerning the alcohol solutions and pure water are gathered in Table I. An example of surface movement is represented on Fig. 2. In Table I, the two cases marked with stars have led in a reproducible way to the following observations. In the first case (*), the solution of n-nonanol is heated by the copper disk, with the whole solution being below the temperature of the minimum of ~r"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003985_tro.2006.878956-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003985_tro.2006.878956-Figure9-1.png",
+ "caption": "Fig. 9. Edge\u2013Vertex case. Angles (left). Projection on the plane (dotted lines) of the contact manifold (right).",
+ "texts": [
+ " (ak; bk; ek) as the map which solves problem (iii) for a specific path pk , theLEV () function is LEV (wi; oj) = min p 2fOPg Lp (EVp (wi; oj)) (18) with Lp(LEV (wi; oj)) = 1 if the contact point lies outside the edge boundaries. 1) Handling Type-B Paths: Let (qi; qi+1) be two adjacent robot vertices. From (9), the linewi can be expressed as y = mi( )x+ni( ), where mi( ) = tan ( + 0 ) ni( ) = qi mi( )qi 0 = arctan l sin( ) l sin( ) l cos( ) l cos( ) and 0 is the angle made by the edge wi and the direction vector !v . Fig. 9 (left) shows, for instance, the angles 0 , 0 relative to two edges w1, w2 for a generic polygonal robot. The coordinates of the target point oj being (ox; oy), the manifold representing oj 2 wi is Cij EV ( ) = f joj 2 wig and is expressed by ijEV ( ) = oy mi( )ox ni( ) = ( ox + x + li cos( + i)) sin ( + 0 ) + (oy y li sin( + i)) cos ( + 0 ) = 0 which describes, as varies, a 2-D surface whose projection on the xy plane is made of straight lines rotating at a fixed distance from oj [Fig. 9 (right)]. Lemma 3: If a Type-B path is optimal for problem (iii), then: 1) line D0 must be perpendicular to the edge wi at the end of the path; 2) the contact point lies at the intersection of D0 and wi. Proof: The constraint f 2 Cij EV , expressed as ijEV ( f) = 0, yields the transversality conditions f = MT , where M = @ ijEV ( f) @ f = [sin ( (tf ) + 0 ) cos ( (tf) + 0 ) ( oy + y(tf )) sin ( (tf) + 0 ) + ( ox + x(tf)) cos ( (tf) + 0 )] : Hence, we get 1 = sin ( (tf) + 0 ) 2 = cos ( (tf) + 0 ) 3(tf) = (( oy + y(tf )) sin ( (tf) + 0 ) + ( ox + x(tf)) cos ( (tf) + 0 )) which yields 2 1 = 1 tan ( (tf ) + 0 ) = 1 mi ( (tf)) (19) 3(tf) = 1 (y(tf) oy) 2 (x(tf) ox) : (20) Equation (19) proves point 1 of Lemma 1; from (20), we have 3(t0) = 1oy+ 2ox, which yields 3(t) = 1(y(t) oy) 2(x(t) ox)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001325_jsvi.2000.3040-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001325_jsvi.2000.3040-Figure4-1.png",
+ "caption": "Figure 4. Response of the axially moving string under a sinusoidal point load and controlled by the &&real-time'' control forces of Figure 2.",
+ "texts": [
+ " The control force which is applied at t c is de\"ned as &&real time'', i.e., it is computed without any knowledge of the response history during 0)t)t c , and the control force which tracks the response history during 0)t)t c as &&simulation''. The latter is suitably termed &&simulation'' because it can be achieved only in simulations but not in real time control. The &&real time'' and &&simulation'' control forces for this example are plotted in Figures 2 and 3. The corresponding responses of the controlled system are shown in Figures 4 and 5. In Figure 4, it is seen that the controlled vibration does not go to zero as a result of nonzero motions at the boundaries when the control forces are applied at t c . However, the controlled amplitude is much smaller than the uncontrolled one. In Figure 5, as predicted by the control laws, the vibration is suppressed to zero in x)a 1 and x*a 2 . Comparing Figures 4 and 5, it is seen that the control is still e!ective in the presence of non-zero initial conditions at non-\"xed boundaries. For this type of feedforward control, disturbances in the uncontrolled regions and boundary excitations can be attenuated by feedback control [36]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002756_pcfd.2004.003789-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002756_pcfd.2004.003789-Figure1-1.png",
+ "caption": "Figure 1 Schematic sketch of a stationary GMAW system (not to scale)",
+ "texts": [
+ " NOMENCLATURE Av constant in equation (20) B\u03b8 self-induced azimuthal magnetic field c specific heat C inertial coefficient e electronic charge f mass fraction F volume of fluid function Fsa surface tension force per unit interfacial area Fsv surface tension force per unit volume g gravitational acceleration h enthalpy hl defined in equation (12) hc effective heat-transfer coefficient \u2206H latent heat of fusion I welding current je electron current density ji iron current density jr radial current density jz axial current density k thermal conductivity keff effective conductivity at the anode-plasma interface K permeability Kb Boltzmann\u2019s constant L latent heat of vaporization n normal direction n\u0302 unit normal vector to the local free surface p pressure Q inflow rate of shielding gas qev heat loss by evaporation r \u2013 z cylindrical coordinate system Rl radius of the electrode 2 R internal radius of shielding gas Re Reynolds number SR radiation heat loss t time T temperature T0 reference temperature for natural convection Tanode anode temperature Tarc arc temperature Te electron temperature Tl liquidus temperature Ts solidus temperature T\u221e ambient temperature u velocity in r-direction v velocity in z-direction V velocity vector Vi ionization potential of the gas Vls relative velocity between liquid phase and solid phase Vr relative velocity between plasma and liquid metal Vw wire feed speed Greek symbols \u03b2T thermal expansion coefficient \u03b4 thickness of anode sheath \u03b3 surface tension \u03b5 emissivity of surface \u03ba free surface curvature \u00b5 viscosity of arc plasma \u00b5l dynamic viscosity of molten metal \u00b50 magnetic permeability of free space \u03c6 electrical potential \u03c6W work function of the anode material \u03c3 electrical conductivity \u03c1 density Subscripts 0 initial condition l liquid phase r relative to solid velocity s solid phase Gas metal arc welding (GMAW) is an arc welding process that uses plasma arc between a continuous, consumable filler-metal electrode and the weld pool, Figure 1. Due to its high productivity, the GMAW process has been the predominant welding method. The welding quality depends on various parameters, such as welding current, electrode, wire feed rate, travel speed, and shielding gas. A comprehensive dynamic model of the GMAW process would provide many helpful insights on key process parameters leading to the improvement of weld quality. In such a model, there are three major coupling events to be considered: 1 the generation and changing process of arc plasma 2 the dynamic process of electrode melting, droplet formation, detachment, and impingement onto the weld pool 3 the dynamics of welding pool under the influences of arc plasma and the periodical impingement of droplets",
+ " In this paper, a two-dimensional mathematical model employing the volume of fluid (VOF) technique and the continuum formulation [19] is developed to simulate the coupled transport phenomena including the arc plasma, electrode melting, droplet formation, detachment, and impingement onto the base metal, and the dynamics of the weld pool. The VOF technique can handle transient deformed weld pool free surface and droplet surface, while the continuum formulation can handle fusion and solidification for the entire metal domain, including the liquid region, the mush zone, and the solid region. Figure 1 shows a schematic sketch of a stationary axisymmetric GMAW process. The electrode is fed downward at a constant speed. A constant current is applied to the electrode, providing heat to melt the electrode and to generate droplets. The inert gas (argon) with fully developed initial velocity profile is also assumed, providing shielding effect to prevent the molten metal from oxidation. Very high temperature arc plasma exists between the electrode and the weld pool, providing additional heat to melt the electrode and the weld pool",
+ " Conservation of current 1 0r r zr r z \u03c6 \u03c6 \u03c3 \u03c3 \u2202 \u2202 \u2202 \u2202 \u2202 \u2202 + = \u2202 \u2202 (8) where \u03c6 is the electrical potential. According to Ohm\u2019s law, the current densities are given by ,rj r \u03c6 \u03c3 \u2202 = \u2212 \u2202 zj z \u03c6 \u03c3 \u2202 = \u2212 \u2202 (9) The self-induced magnetic field B\u03b8 is calculated by the following Ampere\u2019s law: 0 0 d r zB j r r r\u03b8 \u00b5 = \u222b (10) where \u00b50 = 4\u03c0 \u00d7 10\u20137 Hm\u20131 is the magnetic permeability of free space. In order to solve equation (8) to obtain current density, the required boundary conditions for the domain and boundary surfaces as shown in Figure 1 are summarized in the following table: Boundaries AB BD DF FG GA B.C.s 2 1 \u03c6\u03c3 \u03c0 \u2202\u2212 = \u2202 I z R 0\u03c6\u2202 = \u2202z 0\u03c6\u2202 = \u2202r \u03c6 = 0 0\u03c6\u2202 = \u2202r where R1 is the radius of the electrode. Equations (1)\u2013(10) define the basic governing equations and variables describing the physical conditions of the arc, the electrode, and the weld pool. The variables involved are: pressure (p), temperature (T), radial velocity (u), axial velocity (v), electrical potential (\u03c6), radial and axial current densities (jr and jz), and azimuthal magnetic field (B\u03b8)",
+ " In our model, the VOF function of F is chosen to be the characteristic function, and the final expression for Fsv(x) is given by ( ) 2 ( ) ( ) ( )svF x x F x F x\u03b3 \u03ba= \u2207 (14) where the curvature \u03ba(x) is calculated from ( )\u02c6( )x n\u03ba = \u2212 \u2207\u22c5 (15) where n\u0302 is the unit vector normal to the surface, and it is ( ) ( ) ( ) \u02c6 F x n x F x \u2207 = \u2207 (16) Hence, with the volume force Fsv, the surface tension effect at the free surface is modelled as a body force in the momentum transport equation. The boundary conditions for metal domain are summarized into several boundary surfaces as shown in Figure 1. To the surface cells of molten electrode, the surface is a free surface. The arc plasma will not have effects on the velocity of liquid metal. The pressure of the surface cells is equal to the pressure of adjacent arc plasma cells since the surface tension has been converted to a body force. liquid metal arc=p p (17) The friction drag on the surface is [25]: 0 r s V n \u03c4 \u00b5 \u2202 = \u2202 (18) where \u00b5 is the viscosity of arc plasma, Vr is the relative velocity between plasma and liquid metal, n is the normal direction, and the subscript s means at the surface",
+ " / 0v r\u2202 \u2202 = (26) 0u = (27) / 0p r\u2202 \u2202 = (28) / 0T r\u2202 \u2202 = (29) / 0u r\u2202 \u2202 = (30) 0v = (31) / 0v z\u2202 \u2202 = (33) u = 0 (34) For the inflow gas from the nozzle, the radial velocity component is neglected and the axial velocity component is determined as follows [31]: ( ) ( ) ( ) ( ) ( ) 22 2 2 2 22 2 1 2 1 22 2 2 2 14 4 2 1 1 2 1 ln lnln2 \u03c0 ln ln r R RR r R R R RQ rv Vw RR R R R R R R \u2212 + \u2212 = + \u2212 \u2212 + (36) where Q is the inflow rate of shielding gas, R1 is the radius of electrode, R2 is the internal radius of shielding nozzle, and Vw is the wire feed speed. The temperature boundary is T = 300 K. (37) surface (BNM, KJ in Figure 1) Since an interface has a vanishing mass, it cannot store momentum, therefore the velocity must be continuous across the interface: gas liquid metalu u=v v (38) For the temperature boundary condition, the energy equation is modified to include an additional source term _a apS expressing the corresponding cooling effects due to the sheath ( )eff arc anode _ 5 2 b e a ap a R k T T K T S j F e\u03b4 \u2212 = \u2212 \u2212 \u2212 (39) The velocity boundary condition follows equation (38). For the temperature boundary condition, the energy equation is modified to include an additional source term _c apS expressing the corresponding cooling effects due to the sheath ( )_ 5 2 b c ap i i e c R k T S j V j h T T F e \u221e= \u2212 + + \u2212 \u2212 (40) The boundary conditions are the same equations as given in Section 2",
+ " As the droplet contains superheated thermal energy and the base metal is simultaneously heated by the arc heat flux, the droplet does not solidify immediately. In fact, some base metal begins to melt and mix with the droplet. Since the first droplet is not fully solidified before the second one reaches the base metal, a liquid weld pool starts to form immediately after the first droplet. The LHS of Figure 6 shows the velocity profiles for arc plasma corresponding to Figure 5 at 50 L/min of inert gas flow rate; while the RHS figures are for gas flow rate at 10 L/min. The inner diameter of the nozzle is 9.4 mm, as shown in Figure 1. Two streamlines starting from r = 2 mm and r = 4 mm are drawn to show how the gas flow rate influences the shielding effect. At the high gas flow rate (10 L/min), it is seen that the electrode, droplet and weld pool surface all are \u2018protected\u2019 by the inert gas. On the other hand, at the lower gas flow rate (10 L/min), the shielding gas cannot prevent the weld pool from exposure to the ambient air, leading to a possibility of oxidation. While the shielding effects are very different, the gas flow rate does not significantly influence the generation and detachment of droplets and the weld pool shape, as shown in Figure 6"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002201_ac025918i-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002201_ac025918i-Figure10-1.png",
+ "caption": "Figure 10. Effect of the interaction parameter r on the peak broadening. 1 is a CV diagram calculated by taking into account different ionic concentrations inside the film: reduction 5 M, oxidation 0.001 M (eq 9); 2 is a CV diagram calculated by taking into account both different ionic concentrations and interaction parameter: r ) -1.0 (eq 11). Parameters used in the calculations are the same as in Figure 9.",
+ "texts": [
+ " Figure 9 illustrates the effect of the difference of ionic concentrations during oxidation and reduction processes on the peak separation. In the present work, the experimental peak broadening has been described by taking into account the concentration depend- ence of the surface activity coefficients of the redox centers in the framework of the lattice theory (eq 1). The applicability of the lattice theory to our films has been discussed in the previous subsection. Substitution of eq 1 into eq 5 leads to the following expressions: and Figure 10 illustrates the peak broadening when r in eq 11 is negative in accordance with the literature data.31,33,34 As mentioned in the introduction, the negative value of the interaction parameter corresponds to a situation when a mixture of oxidized and reduced molecules is the energetically preferable state, leading to the peak broadening. Thus, eq 11 expresses the reversible voltammetric response of a multilayer film when the interfacial potential distribution and concentration dependence of surface activity coefficients of the oxidized and reduced molecules are taken into account"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001338_0094-114x(95)00082-a-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001338_0094-114x(95)00082-a-Figure5-1.png",
+ "caption": "Fig. 5. Harmonic drive.",
+ "texts": [
+ " On the other hand, very high reduction in single stage gives rise to other design and kinematic problems. In harmonic drives the tooth difference is usually kept to two, which is essential for the kinematic requirement. The possibility of tip interference reduces in harmonic drive as the pinion acts as a flex-spline of elliptical shape. In fact much before the tip interference the rim of the flex-spline deflected inwardly along with the teeth and after the tip interference zone the teeth are again engaged (see Fig. 5). Although there are few reports on the modified tooth geometry for harmonic drives [4, 5] the open literature is lacking in reporting how the tip interference is avoided in such units with involute gearing. The involute profiles are easily cut at lower costs and have some definite advantages over the other conjugate profiles used for gear teeth. The present work, therefore, also aims at crystallizing the theoretical relations on the avoidance of tip interference phenomenon in harmonic drives with involute gear pair",
+ " Also for 22.5 \u00b0 involute gears the difference cannot be lower than 5 even after corrections. On the other hand for 30 \u00b0 involute gears the difference can not be lower than 4 which is achieved without any corrections (see Table 5). Preceding analyses will be useful for circular pinion, i.e. pinion with undeflected rim. The primary concern is to verify the tip interference, after modifying the tooth and keeping the contact ratio within satisfactory limits. In the cases of common type harmonic drives (see Fig. 5) double contacts of the pinion with the internal gear at 180 \u00b0 phase are achieved by allowing the pinion rim to deflect. An elliptical cam is used for this purpose. With such an arrangement dynamic imbalance, as in the case of multiple planet other two gear epicyclic drives, is eliminated. The geometric and kinematic relations of the gears and cam of such a unit are established [4, 5]. However, the conditions of tip interference and its avoidance with reference to the deformed elliptical shape of the pinion are not discussed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002672_j.sysconle.2004.11.014-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002672_j.sysconle.2004.11.014-Figure4-1.png",
+ "caption": "Fig. 4. Non-zero measure invariant sets.",
+ "texts": [
+ " Now consider a transversal section L to the trajectory through z, that is, a closed line segment containing no equilibrium points and such that at every point the field f is not parallel to the direction of L. On this section L, we can find a point y0, arbitrarily close to z, whose -limit is the origin, since this kind of trajectories are dense in the plane. Then, as in the Poincar\u00e9\u2013Bendixson theorem, we can construct a closed path with the negative trajectory through z, a piece of the transversal section L and the positive trajectory through y0.2 This path limits a closed region of the plane, with a finite number of equilibrium points inside it. The first situation we can have is the one shown in Fig. 4(a). On the transversal section, we can find two points whose -limit sets are the origin and their -limit sets are some singular point (could be other than the origin). The trajectories through these points are like the bold ones in Fig. 4(a). The other case is shown in 4(b) and the result is the same as case (a). In both situations, the sets limited by the bold trajectories are invariant and have non-zero Lebesgue measure. This is absurd and then the origin is locally stable equilibrium point. 2 For details of this construction, see [3, Chapter 7]. Remarks. \u2022 If the measure is monotone, then condition (2) is fulfilled for every set with finite -measure. \u2022 If the origin is almost global stable, then the density of the attracted trajectories is fulfilled",
+ " We know that N attracts a dense set of initial conditions to the past and that we can define a Borel measure on the sphere in a way that given any non-zero Lebesgue measure neighborhood Y of N with S /\u2208 Y\u0304 , it verifies 0< (Y ) < \u221e and for every t > 0, [f t (Y )] > (Y ). Then we consider the reversed system x\u0307 = \u2212f (x) on the sphere and we obtain that N attracts a dense set of initial conditions. We can reconstruct the proof of Theorem 3.2, denying the thesis and getting the existence of the bold trajectories of Fig. 4. If the set A enclosed by this curve has finite measure , it is absurd, just as in the previous proof. So, the question we must answer is if S \u2208 A\u0304. But if it was the case, S would be the -limit of the bold trajectories and then S could not attract almost all the initial conditions of the original system. In order to see this, consider again the closed path constructed with the negative trajectory of z, the positive trajectory of y0 and a piece of the transversal section through z. We draw again the picture in Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000673_b006664h-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000673_b006664h-Figure1-1.png",
+ "caption": "Fig. 1 Schematic view of the disposable enzyme sensor based on H+sensitive electrode with integrated Ag/AgCl reference electrode. A, Crosssectional view. B, Front and rear view.",
+ "texts": [
+ " The concentrated enzyme solution was stored at 220 \u00b0C until use. Progress of the purification process was monitored by determining specific activity and by analysis with sodium dodecyl sulfate\u2013polyacrylamide gel electrophoresis (SDS-PAGE). Enzymatic activity was measured by monitoring the change in absorbance at 400 nm, when paraoxon was hydrolyzed to diethyl phosphate and p-nitrophenol (e400 = 17 mM21 cm21) in 20 mM glycine buffer (pH 9.0), 100 mM sodium chloride. One unit (U) of activity is defined as 1 mmol paraoxon hydrolyzed per minute. Fig. 1 shows a schematic view of the screen-printed H+sensitive electrode with integrated Ag/AgCl reference electrode which was used as transducer for the disposable enzyme sensor. The working electrodes were produced in a batch process similar to that described previously.20,24 Conducting lines of the electrodes were screen-printed with silver carbon ink (Auromal L 180, Doduco, Pforzheim, Germany) on a sheet of a 150 mm thick polyester\u2013polyethylene heat sealing film (Team Codor, DUBO-Schweitzer GmbH, Haltern, Germany)",
+ " D ow nl oa de d by U ni ve rs ity o f Il lin oi s at C hi ca go o n 13 /0 8/ 20 13 1 2: 49 :3 6. sensitive membrane and a contact pad of 5 mm length at the electrode\u2019s upper part. The reference electrode was screen-printed on the back side of the heat sealing film of the working electrode using screenprinting ink (Elektrodag 6037 SS, Acheson, Scheemda, Netherlands) with Ag and AgCl in a ratio of 3+2.25 After curing for 1 h at 80 \u00b0C filter paper strips (4 3 20 mm, Schleicher & Schuell, Dassel, Germany) were positioned on the conducting lines (Fig. 1). Encapsulation of the reference electrode was carried out by lamination with a further heat sealing film at 125 \u00b0C leaving a contact pad of 5 mm uncovered at the upper part of the electrode. Upon immersion of the completed electrode in measuring buffer, which contained 100 mM sodium chloride as electrolyte, an opening at the lower part of the reference electrode allowed the spontaneous filling of the filter paper by capillary forces. Preparation of H+-sensitive double matrix membranes (DMM) The working electrodes received the H+-sensitive character by positioning a defined membrane mixture on to the filter paper",
+ "17,26,27 In brief, 300 mg of PCS prepolymer (33.4%) were mixed with 300 ml of 10.0 mM glycine buffer (pH 9.0), 100 mM sodium chloride. Poly(ethyleneimine) (2.5% m/v in water) was added under constant mixing to adjust the pH to 6.4\u20136.5. After centrifugation to remove polymerized particles, PCS and OPH solution (10 000\u2013270 000 U ml21) were mixed at a ratio of 1+1. A total volume of 3.0 ml of the mixture was deposited on the heat sealing film in a spot directly adjacent to the H+-sensitive membrane (Fig. 1) and allowed to polymerize for 30 min at 30 \u00b0C. Subsequently, the sensors were ready for use or stored under dry conditions at 4 \u00b0C. Experimental set-up for sensor measurements All measurements were carried out in a stirred measuring cell containing 2 ml of 1.0 mM HEPES buffer (pH 9.3) and 100 mM sodium chloride at 37 \u00b0C. Stock solutions of OP compounds and Soxhlet extraction of soil samples were prepared with methanol. When adding OP insecticides the change in potential due to the release of protons after hydrolysis was recorded with a microprocessor pH analyser (microprocessor pH meter 3000 with multiplex 3000, WTW, Weilheim, Germany) connected to a computer"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003378_0734-743x(86)90024-2-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003378_0734-743x(86)90024-2-Figure1-1.png",
+ "caption": "FIG. 1. Relative approach: s=z-w.",
+ "texts": [
+ " A physical explanation of this is given in the final discussion of this paper. T H E O R Y A sphere which strikes an infinite, thin shallow spherical shell at normal incidence will be considered. Both the sphere and the shell are assumed to be linear elastic. Elastic impact of spheres 13 An equation of the impact process can be obtained by simultaneously solving the equations of motion for the sphere and for the shell. Taking z as the displacement of the centre of the sphere from its position at initial contact (see Fig. 1), we can write 2=-F/m (l) Here, m is the mass of the sphere, and F is the reaction of the shell to the sphere. Henceforth, F will be referred to as the contact force. Since the shell response is expected to be primarily transverse in nature during the time of contact, longitudinal inertia will be neglected in the description of the shell. First, a concentrated normal impulse load Fog(t), applied at the shell pole, is considered, where Fo is a constant with force dimensions and 8(0 is the Dirac delta function",
+ " As r~ becomes smaller, the 'period', 2~r'rr~, becomes shorter. The shell response to a point load, F(t), of arbitrary time dependence, can thus be expressed as In order to eliminate the unknown impact force F, the Hertzian assumption [11] can be used which states that the stresses and deformations close to the contact area can be 14 M. (;. KoI I,KR and M. 13USl;N.,XRt calculated at any instant as if the contact were static. Consequently, k is essentially a function of the relative displacement s between the sphere and the sheli (see Fig. 1 ). F is explicitly given by F=ks ~:, (5} where s=z-w. 16) The Hertzian constant k is an abbreviation of k 4 E'bE's [ r b ' r ~ 1/2 ( 7 ) where Ks E'b= l _ E - - ~ v b b a n d E ' ~ = ~ . Eb and Vb denote the Young's modulus and the Poisson's ratio, respectively, of the impinging sphere, and rb is the radius of the sphere. A single integro-differential equation may now be obtained in only one dependent variable, s, by differentiating equation (4) twice with respect to time, and then subtracting this equation from equation (1)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003124_0891-5849(88)90101-3-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003124_0891-5849(88)90101-3-Figure4-1.png",
+ "caption": "Fig. 4. Effect of exposure milieu on the inactivation of catalase by ozone. Catalas\u00a2 was diluted to a final concentration of 0.2 mg/ml in the following solvents: chelexed phosphate buffer (50 mM), pH 7.0; unchelexed phosphate buffer pH 7.0; and double distilled water. Solutions were then exposed to ozone and assayed for catalase activity as described in Figure 1. Data from the exposures was exp~ssed as percent activity remaining as function of exposure time. Line A, unchelexed buffer; line B, distilled water; line C, chelexed buffer.",
+ "texts": [
+ "2 mg/ml) was exposed to ozone in double-distilled water, chelexed potassium phosphate buffer (50 mM, pH 7.0), or in unchelexed phosphate buffer, pH 7.0, in order to determine their effect on the rate of inactivation. Chelexed phosphate buffer was prepared according to the method of Buettner 2s by adding chelex 100 resin (100-200 mesh, sodium form) to the buffer (10 g/liter of buffer). The chelex resinbuffer mixture was stirred overnight and subsequently filtered before use. Similar rates of inactivation were observed for catalase solutions exposed in unchelexed buffer or distilled water (Fig. 4). Catalase exposed in chelexed buffer showed an enhanced rate of inactivation in response to ozone (Fig. 4). gers against catalase inactivation by ozone. Bar graph # 1 represents the average percent catalase activity remaining in all the control catalase solutions exposed without antioxidant compounds. Alcohols, scavengers of hydroxyl radicals, were not generally good protectors against catalase inactivation by ozone. Only ethanol exhibited a partial protective effect. Butyl alcohol was not only ineffective as a protectant but had an attributory effect. No significant reduction of the catalase inactivation was observed when catalase solutions were exposed in the presence of superoxide dismutase, a specific scavenger of superoxide radicals"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003628_13.57074-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003628_13.57074-Figure8-1.png",
+ "caption": "Fig. 8. Coupled drive system.",
+ "texts": [
+ "1 and natural frequency 10 rad/s. The transfer function also incorporates two zeros whose locations can be manipulated to illustrate nonminimum phase behavior and transmission zeros on thejw axis in the complex plane. A Material Transport System-ne Coupled-Drives System The aim of this system is to illustrate the type of problems encountered in the production and transport of con- tinuous webs of material such as textile yam, paper, magnetic tape, strip metal, and plastics. The equipment consists (Fig. 8) of two identical dc motors which are coupled by a continuous flexible belt. The belt passes over pulleys mounted directly on the motor shafts and over a jockey pulley. The control objective is to regulate the belt speed and tension at the jockey pulley. The control inputs are the drive voltages to the dc servomotor amplifiers. The servomotors are equipped with tachogenerators; however, the primary output variables are the belt tension and speed as measured at the jockey pulley. Accordingly, the jockey pulley is equipped with a tachogenerator for speed measurement"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001077_1.1533072-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001077_1.1533072-Figure1-1.png",
+ "caption": "FIGURE 1. Schematic of NO delivery system: \u201ea\u2026 stirred chamber of 120 mL; \u201eb\u2026 partial cross section of Silastic tubing and surrounding liquid film.",
+ "texts": [
+ " was prepared by dissolving appropriate amounts of dibasic and monobasic potassium phosphate salts in deionized water, supplemented with 0.1 mM diethylene-triamine-pentaacetic acid ~DTPA!. Phosphate salts, DTPA, potassium iodide, and sulfuric acid were obtained from Sigma ~St. Louis, MO!. A nitrite standard solution was purchased from World Precision Instruments ~Sarasota, FL! and a nitrate/nitrite assay kit was obtained from Kamiya Biomedical Co. ~Seattle, WA!. Delivery Apparatus. As shown in Fig. 1~a!, the delivery device consisted of a closed, liquid-filled container, in which NO and O2 were supplied via separate loops of gas-permeable tubing. The Teflon container of 120 mL ~Cole-Parmer, Vernon Hills, IL, model E-06103-30! had a magnetic stirrer bar ~3.8 cm length, 0.8 cm diameter! placed at the bottom. The container cap was modified to include stainless steel compression fittings for insertion of a Clark-type O2 electrode ~Orion, Beverly, MA, model 810A plus! and a 2 mm diameter NO sensor ~World Precision Instruments, ISO\u2013NO Mark II system",
+ " To investigate the factors that underly the composition dependence of the parameters in the macroscopic model, microscopic diffusion-reaction models were developed for the aqueous boundary layer and membrane. Three such models were examined, differing only in their chemical complexity. The features common to all are described first, and then the special aspects of each model are discussed. The microscopic models were based on a stagnantfilm approximation for the liquid boundary layer. Because each mass transfer coefficient was measured using single-gas delivery experiments, the following models describe mass transfer and/or reactions at the one \u2018\u2018active\u2019\u2019 tubing loop. As shown in Fig. 1~b!, an aqueous film of thickness d was assumed to reside next to a Silastic tube of inner radius ri and outer radius ro . The concentrations in the film and membrane are denoted as C\u0302 j(r ,t) and C\u0304 j(r ,t), respectively, where r is the radial coordinate. ~The relatively thick tubing wall, with ri /ro 50.75, makes curvature important and requires the use of cylindrical coordinates.! Although the concentrations are time dependent, the film and membrane problems are both pseudosteady. That is, the characteristic times for diffusion were all much shorter than the experimental time scale of about 20\u201330 min"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.14-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.14-1.png",
+ "caption": "Figure 1.14. Torsional oscillations around a circle referred to the intrinsic frame.",
+ "texts": [
+ " As a consequence, he always finds ( 1.70) and ( 1.71 ). The relation between motion referred to an arbitrary moving reference frame and motion relative to it will be discussed in greater detail in Chapter 4. To see this more graphically, let us return to our earlier example of the torsional oscillations of a circular disk. The motion, velocity, and acceleration of a particle P on the rim of the disk are given by ( 1.38 ), ( 1.39 ), and ( 1.40) relative to the fixed Cartesian frame cp = { 0; ik} shown in Fig. 1.14a. Guided by our previous discussion of motion on a circle, we know that the intrinsic frame 1/J = { P; tk} has the instantaneous orientation shown in Fig. 1.14a. We want to show that the intrinsic velocity and acceleration components are the 34 Chapter 1 instantaneous projections upon the moving, intrinsic frame 1/J of the velocity and acceleration relative to frame r.p. The relevant problem geometry is illustrated in Fig. 1.14b. It is seen that the instantaneous projections of the unit vectors i and j upon the intrinsic directions t and n are given by i = sin et - cos e n, j = -cos e t - sin e n. (1.77) Substitution of ( 1. 77) into ( 1.38 ), ( 1.39 ), and ( 1.40 ), and use of a familiar trigonometric identity yields the results desired: x(P, t) = -an, v(P, t)= -aflt, a(P, t) = -aD't + afl 2n. ( 1.78a) (1.78b) ( 1.78c) These equations still describe the motion, velocity, and acceleration of P relative to the fixed Cartesian frame r.p = { 0; ik }, but the vectors are now referred to the moving, intrinsic frame 1/1 = { P; tk}. Their new simplicity is evident. Of course, the equations (1.78b) and (1.78c) may be derived directly from (1.74) for the circular motion of a particle. We must remember, however, that e in Fig. 1.14a initially is decreasing in time. Therefore, with w = -8, w = -{J, and r =a, it is seen that ( 1.78b) and ( 1.78c) follow easily from ( 1.74 ). 1.7.4. Some Applications of the Intrinsic Velocity and Acceleration Some examples that illustrate various methods used in the analysis of problems involving intrinsic quantities will be studied next. The formula for the curvature of a plane curve will be reviewed in the solution of the first example, and the formula will be used in two others that follow",
+ " Conversely, suppose that a body moves so that in every motion the velocity of each of its particles is given by (2.27). Prove that the body is rigid. 2.13. Use (1.70), (1.71), and the relation s=pO to derive the equations (2.27) and (2.30) for the rigid body velocity and acceleration of a particle P rotating on a circle of radius p with angular speed (J about a fixed axis a= b. 2.14. Use the geometrical interpretations of the terms in (2.27) and (2.30) to determine the velocity and acceleration of the rim particle P in Fig. 1.14. Check your solutions against (1.78). See Example 1.8. 2.15. Apply equations (2.27) and (2.30) to determine for the conditions specified in Problem 1.12 the velocity and acceleration of the mass M. Note the geometrical nature of the terms computed. 2.16. Employ (2.27) and (2.30) to find the velocity and acceleration of the ball P in Fig. 1.3. Use the conditions described in Example 1.3, and compare your results with those in ( 1.17 ). Observe the geometrical character of the terms computed. 2.17"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure3.17-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure3.17-1.png",
+ "caption": "Figure 3.17. Schematic of consecutive rotational displacements about nonintersecting axes.",
+ "texts": [
+ " Since the second axis is through the displaced point denoted as B', the reversed rotation produces no motion of B'; and the resultant dis placement is a pure translation in which all points of the body experience the same translational displacement d(P) = b0 = b in accordance with (3.160). Thus, reversed rotations about distinct parallel lines will produce a dis placement that is similar to a common walking motion. Although the composition of rotations is not additive, under appropriate conditions, any given displacement may be decomposed into a sum of rotational displacements about certain lines which generally do not intersect. To see this, let us suppose in Fig. 3.17a that for a given displacement (3.161) the resultant rotation about the base point 0 is decomposed into two con secutive rotations R 1 and R 2 about concurrent axes a 1 and a2 , such that a 1 is any given direction and a 2 is perpendicular to the translation vector b*. Since T*=T 1 +T2 R1, (3.161) may be written as d*=T 1x+b*+T 2 x, where X= R I X is the position vector from 0 to the final position r of the particle p Finite Rigid Body Displacements 213 after the first rotation alone. Since a 2 \u00b7 b* = 0, we may apply the parallel axis theorem in Fig. 3.17b to find a parallel line through another base point 0' such that d = b* + T 2 x = T 2 x' is a pure rotation about 0', where x' is the location of P' from 0'. Thus, as shown in Fig. 3.18, the given displacement d*(P) is the sum of two pure rotational displacements d 1 = T 1 x and d2 = T 2 x' about 0 and 0', so that (3.162) Hence, any given rigid body displacement (3.161) may be represented by the sum of two consecutive pure rotational displacements about, in general, non intersecting axes a 1 and a 2 , where a 1 is any assigned direction and a 2 is perpen dicular to the parallel translation vector of the assigned displacement"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002061_jsvi.2001.4018-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002061_jsvi.2001.4018-Figure1-1.png",
+ "caption": "Figure 1. Single mass rotor on a light shaft, running in #uid lubricated bearing.",
+ "texts": [
+ " 1 5 sin 7 t2 , (11a) m \"1/2 I 1 2 # 7 6 cos t# 1 2 cos 2 t# 1 30 cos 3 t! 6 105 cos 5 t! 12 35 cos 7 t2 . (11b) Considering equation (9), the additional forces can be written as f \" Q sin i t, f \" P cos i t. (12a,b) Similarly, according to equation (11), the additional moments may be written as: m \" = sin i t, m \" O cos i t. (13a,b) 3. ROTOR AND BEARING SYSTEM The total de#ection of the rotor is the vector sum of the de#ection of the rotor relative to the shaft ends plus that of the shaft ends in the bearings (Figure 1). The de#ection of the shaft ends in the bearing is related to the force transmitted through the bearings by the bearing sti!ness and damping coe$cients as follows: f \"k m#k n#c mR #c nR , (14a) f \"k m#k n#c m#c n, (14b) where m and n are the instantaneous displacements of the shaft ends relative to the bearings in the horizontal and vertical directions, respectively, and take the form m\" M sin(i t)# M cos(i t), (15a) n\" N cos(i t)# N sin(i t), (15b) f \" F sin(i t)# F cos(i t), (15c) f \" F cos(i t)# F sin(i t)"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003629_ramech.2006.252627-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003629_ramech.2006.252627-Figure1-1.png",
+ "caption": "Fig. 1. Autonomous mini-robot Tinyphoon, http://www.tinyphoon.com",
+ "texts": [
+ " In the presented approach both gyro and acceleration sensors are transiently substituted for wheel encoder data when necessary, thus enabling reliable side-slip angle estimation and tangential slip detection and ultimately allowing for slip control. The proposed navigation system is used in conjunction with the predictive trajectory tracking algorithm from [9]. Experimental results show that the combined navigation and control system enables appropriate tracking of highly dynamic trajectories. The autonomous robot Tinyphoon (www.tinyphoon.com), [10], Fig. 1, has two wheels with rubber tires and two felt shoes, one at the front and one at the rear to stabilise it around the pitch axis. It fits into a cuboid with a 75mm square footprint. The two wheels are supported by ball bearings and powered by two individual DC-motors. Exhibiting a power-mass-ratio of 22.5W/kg, the robot is capable of accelerating far beyond the slip boundary. Its maximum velocity is approximately 4m/s. The robot is equipped with two single-chip two-axis acceleration sensors measuring tangential and lateral acceleration, 1\u20134244\u20130025\u20132/06/$20"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001191_0005-1098(93)90125-d-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001191_0005-1098(93)90125-d-Figure7-1.png",
+ "caption": "FIG, 7. Environment with a mobile robot and a moving obstacle.",
+ "texts": [
+ "t equation (11)-(15) (81) n w ui sin (~\u00b0(s(t))) = u (given), i = l that can be reformulated as max w X w -< r/EF 2 - 2 2 ( f ix+f/y) , i = 1 . . . . . nw, w_>0 equation (11)-(15) n w ui \u00d7 sin (tp\u00b0(s(t))) i = 1 -- u (given in equation (80)), (82) where X = [f ixf ly\" ' fn,xf~,y F l ' ' ' F~w~2wl . The idea behind this optimization is to try to allocate the forces ui in a such a way so that saturation of the available friction at each wheel is avoided. 4. SIMULATION RESULTS In this section a case study is presented. A mobile robot and a moving obstacle with geometric shapes, moving in the same environment (Fig. 7). The shape of both the mobile robot and the moving obstacle is rectangle with dimensions 0.3 m x 0.52 m and 0.28 m x 0.28 m, respectively. The scenario is that when the mobile robot is about to start moving, an obstacle with kinematic parameters x0 = 4.0 m, Y0 = 7.0 m, Vx = 0.04 m sec -1, vy = -0 .075 m sec -1, ax = 0.094 m sec -2, Or = -0.041 m sec -2, is going to collide with it under the current plan. The mobile robot has parameters: Mass (M) : 60 kg. Inertia (Izz) : 32 kg m 2. Maximum accelerating force (U1): 140 N. Minimum decelerating force (U2) : -60 N. Maximum velocity (Vmax) : 8 m sec -2. Wheel-f loor friction coefficient (r/) : -0 .12 . It has the task of going from configuration A to configuration B within T = 12.1753 sec. An offline path planning stage is done and a path r(s) O<-s<-s I with total length s 1 ~ 1 4 . 6 0 m is computed. The parameters of r(s) are indicated on Fig. 7. Initial and final velocities are zero (VA = VB = 0). The resulting velocity profile from the Potential Fields Strategy (PFS) is plotted with solid line on Fig. 8. The dotted ( . . . ) line is the velocity vn(s) of the nominal plan. Line ( - - - ) is the maximum velocity Vmax(S) along r(s). The noisy components of the velocity profile results from the fact that numerical differentiation was actually done to calculate the distance derivatives. The time functions for PFS (tpfs(s)) and the nominal plant (thorn(S)) are plotted on Fig"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002455_j.precisioneng.2004.03.003-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002455_j.precisioneng.2004.03.003-Figure1-1.png",
+ "caption": "Fig. 1. Ball bearing model for calculating NRRO.",
+ "texts": [
+ " 0141-6359/$ \u2013 see front matter \u00a9 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.precisioneng.2004.03.003 The radial NRRO is a problem to be investigated from the viewpoint of ball bearings used in magnetic disc devices. In this research, on the assumption that the ball bearing can be treated as a two-dimensional model, the radial behavior of the center position is analyzed considering the dynamical balance of the Herzian contacting stress between the inner and outer raceways and balls. Fig. 1 shows a NRRO analytical model of the ball bearing. The X- and Y-axes run across the center, O, of the surface of the outer raceway, and x and y represent the coordinates from O\u2032, which is the center of the surface of the inner raceway surface. Since the geometrical errors of the surfaces of the raceways and the balls are small, it is assumed that the balls never slide, but roll perfectly, and have elastic contact with the surfaces of the inner and outer raceways. When the angle of the running inner raceway is \u03c9t , the angles of balls\u2019 positions and the angle of balls\u2019 rotation are given by the following equations"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001968_3-540-45118-8_19-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001968_3-540-45118-8_19-Figure1-1.png",
+ "caption": "Figure 1. Schematic view of the steering device",
+ "texts": [
+ " given sti ness of the inner components increases when reducing the endoscope diameter. Moreover, the technology selection must withstand the sterilization process (140oC during 20 minutes). It has to make the system as simple as possible and to facilitate its manufacturing at small scale. The controllably bendable portion of the instrument must be able to adapt Segments its local curvature to the interior geometry by a spontaneous reaction to the interactions with the environment while the viewing tip follows a track in a vessel or in a cavity. Figure 1 schematically illustrated the endoscopic system we designed. The mechanical structure of the device can be viewed as an hyper-redundant manipulator which embrace the endoscope components (optic bundle, light guides, tool chanels). It is a serial arrangement of tubular segments articulated to each other by pin joints. This design is modular, the number of segments can be adjusted to the application and is in theory in nite. On the actual design, the segment length is 4 mm, the inner diameter 5.4 mm and the outer diameter (including the outer elastomer cover) is 8 mm"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.15-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.15-1.png",
+ "caption": "Figure 4.15. Simple relative motion of a ball apparent to a ferris wheel rider.",
+ "texts": [
+ "51 ), we have vJ/=0 and a11 =0; that is, no particle may have a nontrivial velocity or acceleration relative to itself Thus, by (4.51), the mutual velocity and acceleration vectors for each pair of origin points are equal and oppositely direc ted: (4.52) Finally, with the aid of (4.51), we derive the following kinematic chain rules for simple relative motion: ( 4.53) a,o= an,n- l +an-l,n-2 + ''. + a2l + alO\u00b7 The easy application of the foregoing chain rules will be demonstrated next. Motion Referred to a Moving Reference Frame and Relative Motion 265 Examples 4.8. The ferris wheel shown in Fig. 4.15 is turning with a con stant, counterclockwise angular speed w = (1/2) radjsec (about 5 rpm). A ball v BG = ~ 15i ~ 4j ft/sec, aBG = ~32j ftjsec 2\u2022 (4.54a) What are the velocity and the acceleration of the ball apparent to the rider at the position shown? Assume that the seat does not swing to and fro about its axle. Solution. Since the seat does not swing about its axle, as the wheel turns, the moving frame rp at A always remains parallel to the ground frame r[J at G. Therefore, bearing in mind the assigned data in ( 4",
+ "54a ), the velocity and the acceleration of the ball B relative to the rider A are given by the chain rules (4.51): (4.54b) It remains to determine the velocity and the acceleration of G relative to A. Since point 0 is fixed in rfJ, the absolute velocity and acceleration of A in r[J are given by (2.27) and (2.30). Taking into account the rule (4.52), we find VAG= ~vGA = V AO = 0) X X= 10j ft/sec, aAG= ~aGA=aA0 =rox(roxx)= ~5ift/sec2, (4.54c) wherein x = 20i ft and ro = ( 1/2) k rad/sec in accordance with Fig. 4.15. Of course, m=O in (2.30). Thus, substitution of (4.54a) and (4.54c) into (4.54b) determines the velocity and acceleration of the ball apparent to the rider: v BA = ~ 15i ~ 14j ft/sec. anA= ~32j + 5i ft/sec 2. (4.54d) 266 Chapter 4 Since the frames are parallel, the results may be referred to either basis set with ik = Ik. 0 Example 4.9. A pin P shown in Fig. 4.16 is constrained to move in a cir cular groove milled to a radius of 3ft in a large rectangular plate. The pin also slides in the straight slot of a slanted link mechanism which is moving toward the right with a constant speed of 5 ftjsec"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003688_tcst.2004.833622-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003688_tcst.2004.833622-Figure1-1.png",
+ "caption": "Fig. 1. (a) TVC actuator with single nozzle and rolling torque scheme. (b) Missile\u2019s divert control system (bottom view). (c) Two angles of TVC in body coordinate frame.",
+ "texts": [
+ " A missile equipped with thrust vector control (TVC) can effectively control its acceleration direction [1] when the missile\u2019s fin fails, which in turn implies that the maneuverability/controllability of the missile can be greatly enhanced during the stage when the speed of the missile is slow and/or the air density surrounding the missile is low. In this brief, we investigate the variable structure (VS)-based missile guidance/autopilot problem for a missile equipped with TVC and divert control system (DCS) so that the intercepting missile is able to fulfill the purpose of successful interception of an inbound target missile in a single intercepting phase. The motion of a missile can be described in two parts as follows: Translation: (1) Rotation: (2) where , and all the variables are defined in the nomenclature. After referring to Fig. 1(a)\u2013(c), the force and torque exerted on the missile can be, respectively, expressed in the body coordinate frame as (3) (4) where is the aforementioned variable moment in the axial direction of the missile. Let the rotation matrix denote the transformation from the body coordinate frame to the inertial coordinate frame. From (1) to (4), the motion model of the missile can then be written as (5) (6) where and . B. Zero-Effort-Miss Phase Assume that both the missile and the target are moving only with constant gravitational acceleration, i",
+ " Accordingly, the desired overall acceleration perpendicular to the LOS can be derived due to the result in Section III, which together with in the direction leads to the desired acceleration (see Fig. 3) of the missile, namely Hence, the resulting acceleration of the missile due to TVC and DCS together will lie on the plane . We note the following two facts: 1) projection of the desired resulting acceleration onto the axis of is simply and 2) projection of onto the axis perpendicular to the plane will be identically zero. Then, we can derive the following constraint equations of in the body coordinate frame as: By Cramer\u2019s rule, the acceleration [see Fig. 1(b)] generated by the divert control system, denoted as , can be derived as Remark 1: To avoid the singularity for computing the , we propose one possible solution to modify the force from the divert control system when the singularity condition \u201c \u201d occurs as follows: and if and if To validate the proposed sliding-mode guidance and autopilot of the missile system, we provide a realistic computer simulation in this section. We assume the target is launched from somewhere 600 km far away. The missile has a sampling period of 10 ms"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003477_cnm.913-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003477_cnm.913-Figure3-1.png",
+ "caption": "Figure 3. Symmetric graph with the canonical form II symmetry and its factors: (a) D; and (b) C.",
+ "texts": [
+ " Canonical form II: For this case, matrix [M] can be decomposed into the following form: [M] = [[A]n\u00d7n [B]n\u00d7n [B]n\u00d7n [A]n\u00d7n ] N\u00d7N (8) The eigenvalues of [M] can be calculated as { (M)} = { (C)}\u222a{ (D)} (9) Copyright q 2006 John Wiley & Sons, Ltd. Commun. Numer. Meth. Engng 2007; 23:639\u2013664 DOI: 10.1002/cnm where: [C] = [A] + [B] and [D] = [A] \u2212 [B] (10) [C] and [D] are called condensed submatrices of [M]. The axis of symmetry in a graph of the form II symmetry passes through the members but not the nodes. The members cut by the axis of symmetry are called link members. Link members connect two isomorphic subgraphs S1 and S2 to each other. Figure 3 shows a symmetric graph with the canonical form II and its decomposed factors. Canonical form III: This form has a form II submatrix augmented by some rows and columns as shown in the following: [M] = \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a3 L11 . . . L1k [A] [B] L21 . . . L2k Ln1 . . . Lnk L11 . . . L1k [B] [A] L21 L2k Ln1 . . . Lnk C(2n+1, 1) . C(2n+1, 2n) C(2n+1, 2n+1) . . . C(2n+1, 2n+k) . . . . . . . . Z(2n+k, 1) . Z(2n+k, 2n) Z(2n+k, 2n+1) . . . Z(2n+k, 2n+k) \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a6 (11) where [M] is a (2n + k) \u00d7 (2n + k) matrix, with a 2n \u00d7 2n submatrix with the pattern of form II, and k augmented columns and rows"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000577_(sici)1521-4109(199911)11:17<1259::aid-elan1259>3.0.co;2-b-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000577_(sici)1521-4109(199911)11:17<1259::aid-elan1259>3.0.co;2-b-Figure5-1.png",
+ "caption": "Fig. 5. Schematic diagram of the \u00aerst electrode design.",
+ "texts": [
+ " It should be noted that methylene blue binds to the surface of Zr(HPO4)2 whether crystalline or amorphous, but it was found that photocurrents obtained with a mixture of methylene blue and amorphous Zr(HPO4)2 were signi\u00aecantly smaller than those obtained after methylene blue had been intercalated into the lattice. In initial photochemical experiments the working electrode and light pen were aligned manually and were separate, the working electrode consisting of a Te\u00afon rod with a copper rod along its central axis. The end of the Te\u00afon contained a hole of diameter 5 mm and depth 0.5 mm which was \u00aelled with the graphite=mineral oil=a-Zr(HPO4)2 H2O mixture. This experimental set-up is shown in Figure 5. However, the initial success of this electrode in exhibiting signi\u00aecant photocurrents with ascorbic acid led to the development of an all-in-one light source and working electrode. Analytical measurements were made using this novel design of the electrode, which is shown in Figure 6. Graphite (99.9 %, Aldrich) was crushed using a pestle and mortar before mixing with the dye=phosphate compound, this was also mixed with mineral oil. ESR experiments were performed using a Bruker ER 200D \u00b1 SRC spectrometer, at a centre \u00aeeld value of 3500 G, with a sweep width of 150 G, in accordance with procedures outlined previously [12]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000385_s0045-7949(98)00165-5-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000385_s0045-7949(98)00165-5-Figure5-1.png",
+ "caption": "Fig. 5. Simply supported laminated shell (three graphite-epoxy layers with orientations 908/08/908 referred to the global y-axis). Geometry and material properties (y= 308).",
+ "texts": [
+ " Again one-quarter of the plate was analyzed due to symmetry. Results are shown for two di erent meshes (m = 2 and m = 4) giving practically the same period and small changes in the amplitudes. The same results are practically obtained when the number of analysis layers increases. This example corresponds to a simply supported laminated cylindrical shell. The shell is composed by three graphite-epoxy layers of high elastic modulus. The orientations are 908/08/908 referred to the global y-axis (Fig. 5). Fig. 5 also shows the geometry and material properties. The analysis is made by considering three di erent meshes: 4 4, 6 6 and 8 8 elements. For computational purposes the thickness is divided into 3, 6 and 24 analysis layers for the 4 4 mesh and in 24 layers for the other meshes. Table 4 shows some numerical results for the displacement and stresses at di erent points. The variation of the displacements across the thickness is shown in Fig. 6. Fig. 7 displays the distribution of syz and sxz across the thickness"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003443_bf00934465-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003443_bf00934465-Figure3-1.png",
+ "caption": "Fig. 3. Optimal accelerations for a given \u00a2*.",
+ "texts": [
+ " (26) and (27) yield A (0) = A (0) = y(O)/II y(0)tl ~- -\u00a2*, (28) (* being a constant unit vector on each optimal trajectory. (26) (27) JOTA: VOL, 43, NO. 3, JULY 1984 437 The candidate optimal strategy pair can now be determined by u*, v* = arg rain max H = arg max min H, (29) u~U v c V v~V u~U yielding U* = -- a e M T M p ~ * / II MeG* li, (30) v* = -aeMT Mz~*/I1ME~:* II, with P L 0 ME=[C\u00b0oXE ~]. (31) The optimization results by maximizing the projection of the admissible accelerator vector on the direction opposite to the unit vector ~*, as depicted in Fig. 3. From this figure, it is easy to see that the respective acceleration components in the Y and Z directions are u* = ae sin \u2022*, and (32) and Op(~) a= HMe(II = (~:~ cos z Xe + ~2)1/2 OE (~) A lfM~sCl[ = (sc~ cos 2 Xz + ~:~)1/2. (38) This candidate solution is indeed optimal if the sufficiency condition, requiring smooth isocost surfaces (Ref. 8), is satisfied. The construction of the isocost surfaces has to be carried out in two consecutive steps, using Eq. (36) for both. First, the direction of ~* maximizing the bracket in Eq",
+ " (35) The optimal cost j* = I[Y*(0)l I can be obtained by multiplying the vector y*(0) by a unit vector in its own direction. Such vector is -~* [see Eq. (28)]. The search for this, a priori unknown, direction is the major part of the optimal game solution. Since any point in the game space (y, 0) can be considered as an initial condition, J*(y, O)= sup { -~Ty -p (O)Qe( ( )+e (O)O~( ( ) } , (36) tJ~tl = a with p(O) ~= ap@[02/2 - ~0(0)], e(O) A= a .r2(02/2), (37) JOTA: VOL. 43, NO. 3, JULY 1984 439 can be characterized by the angle/3\" (see Fig. 3), ~:* = -cos fl*, ~* = -sin/3\", (39) and the solution can be expressed as /3* =/3*(y, 0). (40) The next step is to substitute Eq. (40) into Eq. (36) and to set a constant value C for J*, J*[y, o,/3*(y, 0)] = C. (41) This last expression is the equation of the isocost surface J* = C to be tested for smoothness. is the existence of a unique solution/3* of Eq. (36) for any given (y, 0). The maximization process (using/3 as the variable) leads to the following equation: Yl sin/3 - Y2 cos fl + sin/3 cos/3 [ p ( 0 ) / Op (/3) ] sin 2 Xe - [e(0)/Q~ (/3)] sin 2 XE = 0, (42) where Qp(/3) and QE (/3) are obtained by substituting Eq",
+ " Singularity is detected when, in a part of the state space, the gradient of the optimal cost cannot be uniquely defined. The origin of this singular behaviour is the difference in the minor to major axis ratios of the respective ellipses (cos Xv > cos X~, as shown in Fig. 2). This property is an inherent feature of the missile/aircraft collision course trajectory for Ve > VE and sin XE ~ 0 (see Fig. 1). As a consequence of this difference, the effective missile/aircraft maneuver ratio ~er, defined in Eq. (48), depends on the gradient direction (see Fig. 3), indicating the preference of the evader to orient its acceleration in the direction of the major axis ([3* -- ~r/2). The singular region of the state space is small. It is confined to a part of the plane of symmetry Y2 = 0 inside the isocost tube J * = Cx [see Eq. (55)] for 0 < 0x [Eq. (53)] only. This region is divided into two different JOTA: VOL. 43, NO. 3, JULY 1984 455 types of singular surfaces (see Fig. 11): a dispersal zone of the evader D1XOs and a focal surface FIXOs. The dispersal zone is a set of initial conditions (Yl, 0) for a pair of symmetrical trajectories departing toward opposite y2-directions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002529_s0379-6779(02)00099-1-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002529_s0379-6779(02)00099-1-Figure2-1.png",
+ "caption": "Fig. 2. Cyclic voltammograms of Ni electrode between 0.2 and 0.6 V at different scan rates subsequent to an initial cycle in the potential range between 0.2 and 1.2 V in 0.5 M H2SO4 consisting of 0.1 M aniline and 50 mM Fe2\u00fe/Fe3\u00fe.",
+ "texts": [
+ " However, there is a simultaneous increase in DEp. After about four cycles, there is a rapid increase in DEp (Fig. 1 inset). Thus, this experiment facilitates monitoring of the redox process simultaneously with the growth of PANI layer on Ni. In another type of experiment, a thin layer PANI was deposited on the Ni in 0.5 M H2SO4 \u00fe 0:5 M aniline\u00fe 50 mM Fe2\u00fe=Fe3\u00fe during the initial potentiodynamic cycle between \u20130.2 and 1.2 V, and subsequently cycled in the same electrolyte only between 0.2 and 0.6 V (Fig. 2). The redox peaks of Fe2\u00fe=Fe3\u00fe reaction alone appear in the potential range between 0.2 and 0.6 V and the values of ip and DEp remain unaltered for repeated potential sweeps (not shown) at a given scan rate. Since the potential sweep is reversed at 0.6 V, further growth of the PANI (which occur at a potential of >0.6 V) does not take place and therefore thickness of the PANI remains unaltered. As a result, the voltammograms corresponding to Fe2\u00fe=Fe3\u00fe are reproducible during repeated cycling at a given scan rate, and the magnitude ip increases with an increase in sweep rate (Fig. 2). Furthermore, the electrode was removed from the electrolyte, washed repeatedly in 0.5 M H2SO4 and cyclic voltammograms were recorded in 0.5 M H2SO4 containing 50 mM of Fe2\u00fe=Fe3\u00fe electrolyte. The voltammograms recorded at several sweep rates were identical to those shown in Fig. 2. In the experiments described above, the electrolyte contained Fe2\u00fe=Fe3\u00fe redox species during the deposition of PANI. It may be anticipated that Fe2\u00fe and/or Fe3\u00fe ions are included within the PANI layer. The catalytic behaviour of the PANI on Ni may thus be attributed to the included ions. In order to examine this aspect, PANI was deposited on Ni during the initial potential cycle in 0.5 M H2SO4 \u00fe 0:1 M aniline (hereafter referred to as PANI modified Ni electrode), the electrode was copiously washed in 0.5 M H2SO4, and then cycled between 0.2 and 0.6 V in an electrolyte of 0.5 M H2SO4 containing 50 mM of Fe2\u00fe=Fe3\u00fe. The voltammograms of the redox reaction (Fig. 3) resemble to those shown in Fig. 2 in shape as well as in magnitude of the peak currents and the peak potential values. These results suggest that the catalytic behavior of PANI deposited in presence and absence of redox ions is alike towards reaction (1). For the purpose of comparison, cyclic voltammograms of both Pt and PANI modified Ni electrodes were recorded in 0.5 M H2SO4 supporting electrolyte consisting of Fe2\u00fe=Fe3\u00fe (Fig. 4). Peak current of the PANI modified Ni electrode is higher than that of the Pt electrode. Similar observation is made at several concentrations of the redox couple and several sweep rates"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002606_iros.1997.655141-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002606_iros.1997.655141-Figure2-1.png",
+ "caption": "Figure 2: Classical approach",
+ "texts": [
+ " H will be written as follows : Note that H components for each position and orientation of the gripper are directly supplied by the outputs of the robot encoders. 0 L : homogeneous transformation matrix from F,, to Fe. L must be computed by performing extrinsic calibration. However, it should be stressed that the extrinsic calibration is in most cases greatly dependent on intrinsic parameters calibration and 1059 image detections. sometimes quite inaccurate. So, L estimation might be (7) R1 3 L = ( o 1 ) According to the figure 2, it is obvious that AX = X 3 (8) (3) 0 T : homogeneous transformation matrix from Fm where A and B are known and X represents the handeye calibration transformation that is to be estimated. t.o Fm - I ' _ _ At least three different robot motions are necessary to solve the system [3]. In practice, a set of n positions ( n 2 3) is selected and the system is overdetermined. T represents the location of the calibration object in the robot world coordinate sytem. There is a lot of possibilities to solve for (AiX = X B i ) i E [l..n] (9) (4) Rt Tt T = ( 0 1 ) 0 X : homogeneous transformation matrix from Fe to Fh is the unknown hand-eye transformation. (5) Figure 1 explains the relationships between the different frames and the various homogeneous matrices. 2.2 Classical Approach Let's consider two different positions i and j of the gripper inside the robot workspace (see fig.2). Then, matrices H and L have to be indexed by i and j corresponding to these two different stations of the gripper. Matrix X doesn't have any index since the camera is rigidly mounted on one of the robot links. As H, and H j are known, it is possible to estimate the transformation A that gives the location of the second gripper position relative to the first position. A = (Ha)-'(Hj) (6) Similarly, Li and Lj can be computed and it is also possible to determine B : [a] and [3] propose closed-form solutions"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001338_0094-114x(95)00082-a-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001338_0094-114x(95)00082-a-Figure2-1.png",
+ "caption": "Fig. 2. Gear geometry for contact ratio.",
+ "texts": [
+ " However, minimum value of (Z s - Zp) after avoiding tip interference will be further limited by the accepted value of contact ratio. 2.2. Contact ratio Both the approach contact and recess contact vary with the addendum truncation as well as center distance modification. With a greater number of corrections sometimes one of them becomes negative although their sum remains positive and gives a satisfactory contact ratio. But it is undesirable for gearing action. Therefore, in the present work these two contacts are verified separately in computation. Referring to Fig. 2 (ring gear is the driver in gearing action) the approach contact (CP) ac, recess contact (PB) re and contact ratio Cr are expressed as a\u00a2 = x/~2p - r~,p - rp sin g (3) r~ = r~ s in ~t -- ~ - - r~g (4) C, = (ac + rc)/(zcm cos ~0) (5) Minimum tooth difference 477 where, rp and rg are the working pitch circle radii, rap and rag are the tip radii and rbp and rbg are the base circle radii of the pinion and gear respectively, ~ and ~0 are the working and standard pressure angles respectively, and m is the standard module"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003657_j.cma.2005.02.033-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003657_j.cma.2005.02.033-Figure3-1.png",
+ "caption": "Fig. 3. Open-loop multibody system [4].",
+ "texts": [
+ " (2) Spherical joint\u2014in this case, the orientation of the body on the distal side of the spherical joint is measured relative to the ground body. Once again, the indirect coordinates correspond to the absolute angular coordinates for the distal body. (3) Two prismatic joints with parallel axes\u2014the translation of the body on the distal side of the distal prismatic joint is measured relative to the body on the proximal side of the proximal joint. This rule is very similar to rule 1 for revolute joints. To demonstrate, consider the example from Fayet and Pfister shown in Fig. 3. Four bodies (m1, m2, m3, m4) are connected in series to the ground by a revolute joint (h12), two revolute joints (h13 and h14) with parallel axes, and a spherical joint (b15). The indirect coordinates for this system consist of the first and second revolute joint coordinates, which locate m1 and m2. The orientation of the third body m3 is measured relative to m1 using rule 1 above. Finally, the orientation of the distal body m4 is measured relative to the ground, in accordance with rule 2. Fayet and Pfister present a systematic formulation of the kinematic and dynamic equations for open-loop systems in terms of indirect coordinates, and give some examples of the resulting simplifications in the dynamic equations",
+ " To extend this graph-theoretic approach to indirect coordinates, the concept of \u2018\u2018virtual joints\u2019\u2019 must be introduced. Essentially, a virtual joint, sometimes called a \u2018\u2018free\u2019\u2019 joint or sensor element, is used to measure the relative motion of any two bodies in a system. The joint is \u2018\u2018virtual\u2019\u2019 since it does not necessarily correspond to a physical joint in the multibody system. To demonstrate, consider the linear graph shown in Fig. 7. This graph represents Fayet and Pfister s multibody system from Fig. 3, which is superimposed on the graph in dotted lines. The graph consists of four rigid body elements m1 m4, seven arm elements r5 r11, three revolute joints h12 h14, and one spherical joint b15. In addition, two virtual joints are added to the graph: a virtual revolute joint vh16 between bodies m1 and m3, and a virtual spherical joint vb17 between the ground and body m4. These virtual joints correspond to Fayet and Pfister s guidelines for defining indirect coordinates, described previously in Section 2"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003610_j.aca.2005.08.037-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003610_j.aca.2005.08.037-Figure2-1.png",
+ "caption": "Fig. 2. Schematic representation of the design used for the optical flow-cell: (1) quartz slide with two holes, (2) clamp for fixation, (3) Teflon tubing for sample flow, (4) glass tube glued to the quartz slide used for housing the Teflon tubing, (5) quartz slide as substrate for the optical film, (6) sensing film, and (7) Teflon gasket to control the cell volume.",
+ "texts": [
+ " 1A for chemical structure), sodium perchlorate, sodium odide, 2-morpholinoethanesulfonic acid (MES), sodium saliylate, and sodium nitrate were purchased from Sigma\u2013Aldrich ntific; Pittsburgh, PA) was positioned by applying vacuum in spin-coating device (model SCS-G3-8 obtained from Cookon Electronics; Providence, RI). The quartz plate was rotated t 600 rpm, and 100 L of the membrane cocktail was injected nto the rotating glass plate. After spinning for \u223c5 s, the quartz late coated with the thin polymeric film was removed from the pin coater and dried in air for \u223c10 min. When not in use, the lm was stored in the dark. The thickness of the sensing film was estimated to be in the range of 2\u20133 m [23] (see Fig. 2 in Ref. [23]). A quartz plate coated with the fluoride sensitive film was mounted in a custom-built spectrophotometer flow-cell (see Fig. 2 for schematic representation of this cell). The sample volume of the cell was estimated to be about 25 L when using a Teflon gasket with a thickness of 0.14 mm. The flow-cell was then mounted into a Perkin-Elmer double-beam UV\u2013vis spectrophotometer (model Lambda 35; Boston, MA). Using a Gilson Minipuls-3 peristaltic pump (Middleton, WI), a buffer was allowed to flow over the surface of the film for 20 min with a flow rate of 1.4 mL/min to pre-condition the sensing film. The response of the optical sensing film toward different anions was evaluated by adding known aliquots of the test solution to a stirred reservoir containing 50 mL of buffer",
+ " L+ + Ind\u2212 + H+ (a) + F\u2212 (a) IndH + LF (1) The co-extraction constant (K) corresponding to this equilibrium is expressed as: K = [IndH][LF] [Ind\u2212][L+] 1 aH+ \u00b7 aF\u2212 (2) To describe the response characteristics of this sensor system, it is quite useful to use the relative absorbance, \u03b1 [28], which is the fraction of the total indicator (IndT) that is present in the d \u2212 i \u03b1 w a u p s a a K m r K a i a acid dye (Ind\u2212) to ensure electroneutrality in the bulk of the thin polymeric film (see sensing scheme in Fig. 3). This protonation of the chromoionophore leads to a large change in the absorbance of the optical film. Indeed, as shown in Fig. 4, the absorbance spectrum of a polymeric film formulated with 2 DOS:1 PVC and impregnated with Al-Sal/ETH-7075, measured in 50 mM glycine-phosphate buffer, pH 3.00, is highly dependent on the fluoride ion concentration in the bathing sample phase (using flow-through configuration shown in Fig. 2). With increasing fluoride concentrations, the extent of protonation of the acid dye in the film by proton co-extraction becomes greater, yielding a lower absorbance for the deprotonated form of the indicator (\u03bbmax = 529 nm) and higher absorbance of the protonated form (\u03bbmax = 441 nm) with an isobestic point at 474 nm. Plotting the background corrected absorbance values at 529 nm versus the total fluoride concentration (Fig. 5) demonstrates that the Al-Sal based optical film responds with high sensitivity to fluoride with a sub-micromolar detection limit and a dynamic measurement range from 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003635_rob.4620060406-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003635_rob.4620060406-Figure1-1.png",
+ "caption": "Figure 1. Elastic links.",
+ "texts": [
+ " In cases of flexible arms, the transformation Low: Solution Schemes for the System Equations of Flexible Robots 385 matrices are, in general, functions of the corresponding joint displacements and the elastic slopes. In the following, a derivation for the kinematic equations of flexible robots is first presented. The author then introduces a general transformation matrix associated with the elastic deformation. Consequently, the possibilities of simplifying the expression of the matrix from the assumption that the strain components and elastic slopes are small compared to unity are investigated. As shown in Figure 1, the position vector for the tip-point of a flexible robot (point 2\u201d\u2019) relative to the origin of the inertial frame is expressed as PI = Pi + D1+ (P2 + C2) + D2 PI = Roipi + Roidi + RoiR11, R 1 2 ~ 2 +RoiRi I* R142 (1 ) (2) in which Ro, and RIP2 are the transformation matrices associated with the rigid-body motion, whereas R l l , is due to the elastic slopes of the end of the previous link. The vectors pi and dj ( j = 1.2) denote the vectors relative to local coordinate systems. Note that system 0 is the inertial frame"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002517_1.1515324-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002517_1.1515324-Figure4-1.png",
+ "caption": "Fig. 4 Change of constraints by foot change",
+ "texts": [
+ ", we can derive the equation of motion in the second phase as follows: F M 11 M 121M 13 M 121M 13 M 2212M 231M 33 G H u\u03081 u\u03082 J 1F 0 c121c13 2c122c13 2c23 G 3H u\u03071 2 u\u03072 2J 1 H K1 K21K3 J 5 H 0 0J . (2) Equation ~2! is rewritten in the form, u\u03085 f ~u , u\u0307 ! (3) where u5$u1 ,u2% T. 2.4 Angular Velocity Variation Caused by Foot Exchange. In this analysis, it is assumed that the toe collision is plastic and the foot exchange takes place instantly for the sake of analytical simplicity. As shown in Fig. 4, u\u0307 i p4 represents the angular velocity of link i at the moment right before the foot exchange ~posture 4 in Fig. 2!, whereas u\u0307 i p5 stands for the angular velocity of link i at the moment right after the foot exchange ~posture 5 in Fig. 2!. The analytical model of link i at the instant of the foot exchange is shown in Fig. 5. Pi and Pi11 are the impulses caused by the collision at the joints i and i11, respectively. The impulsemomentum equations for link i are written in the forms, mi~v ix p52v ix p4",
+ "5Pix2P (i11)x mi~v iy p52v iy p4!5Piy2P (i11)y (4) I i~ u\u0307 i p52 u\u0307 i p4!5ai3Pi1~ li2ai!3Pi11 556 \u00d5 Vol. 124, DECEMBER 2002 rom: http://dynamicsystems.asmedigitalcollection.asme.org/ on 01/28/201 where v i p4 is the mass center velocity of link i at the moment right before foot exchange and vi p5 is the mass center velocity of link i at the moment right after the foot exchange. Before the foot exchange, the swing leg is in a straight line and the analytical model is a 2-dof link system as shown in the left side of Fig. 4. After the foot exchange, however, the model turns into a 3-dof system. The relationship of the link angular velocities during the foot exchange is derived from ~4! as follows: F H11 H12 H21 0 H31 0 G H u\u03071 p4 u\u03072 p4J 5F M 11 M 12 M 13 M 22 M 23 Sym M 33 G H u\u03071 p5 u\u03072 p5 u\u03073 p5 J , (5) where M i j is the same as Eq. ~1!, and Hi j is as follows: H1152@m1a11m2~ l21l32a2!1m3~ l32a3!#l1 cos~u12u2! H125I12m1a1~ l12a1! H215I22m2a2~ l21l32a2!2m3l2~ l32a3! H315I32m3a3~ l32a3!. 2.5 Cyclic Walking Locomotion Condition",
+ " In order to realize the cyclic walking locomotion, the motion state at posture 5 must be the same as that at posture 1. Therefore, we get up55up1 (6) u\u0307p55u\u0307p1 We note that there are two zero elements in @H# as shown in Eq. ~5!. By substituting the formula ~6! into Eq. ~5!, we have the relationship between u\u03071 p1, u\u03072 p1 and u\u03073 p1 of the form, Transactions of the ASME 6 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F S M 212 H21 H31 M 31D u\u03071 p11S M 222 H21 H31 M 32D u\u03072 p11S M 23 2 H21 H31 M 33D u\u03073 p150 (7) The angular position at posture 4 is calculated as follows from Fig. 4 and Eq. ~6!: u1 p45u2 p11p (8) u2 p45u1 p12p . From Eqs. ~5! and ~6!, the angular velocities u\u03071 p4 and u\u03072 p4 are solved as functions of u\u0307p1 as follows: u\u03071 p45 1 H21 ~M 21u\u03071 p11M 22u\u03072 p11M 23u\u03073 p1! (9) u\u03072 p45 u\u03073 p45 1 H12H21 ~a u\u03071 p11b u\u03072 p11c u\u03073 p1!. where a5H21M 112H11M 21 , b5H21M 122H11M 22 , c5H21M 13 2H11M 23 . By setting c15u and c25 u\u03075c\u03071 , Eq. ~3! is rewritten in the following form of one order differential equation c\u03075H c\u03071 c\u03072 J 5 H c2 f ~c1 ,c2!J 5L~c!. (10) We apply the backward time Runge-Kutta integration method and integrate Eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000517_1616-8984(199607)1:1<1::aid-seup1>3.0.co;2-6-Figure1-10-1.png",
+ "caption": "Figure 1-10. Slab waveguide-based SPR [359].",
+ "texts": [
+ " Both principles are illustrated in Figure 1-9. 1.2 Principles of Optical Transduction 17 As in the case of intrinsic fiber optics, guided radiation can be used to couple via a buffer layer to a metal film and excite surface plasmons at the opposite interface. Suitable refractive indices for buffer layers and the correct wavelength guided in the waveguide are necessary to find a resonance condition. Such devices (slab waveguide-based SPR) can be used as sensing systems [359]. A schematic representation is shown in Figure 1-10. First attempts have been undertaken to achieve a multi-element surface plasmon resonance chip. Using the set-up with a variation of the angle of incidence, four sensor elements have been published [299]. In contrast, the slab waveguide-based SPR chips are expected to allow even more elements to be interrogated, since optical micro-structuring becomes a common process. Recently, fiber optical-supported surface plasmon resonance spectroscopy [235] has been developed using coated multimode fibers excited by polychromatic light"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002517_1.1515324-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002517_1.1515324-Figure3-1.png",
+ "caption": "Fig. 3 3-dof analytical model of a biped walking mechanism",
+ "texts": [
+ " Here, the toe collision is also assumed to be inelastic, so that the toe does not bounce from the ground. From posture 5, the next step starts. Because both the knee collision and foot exchange take place instantly, the one step period is t11t2 . An efficient and natural walking locomotion of a 3-dof walking mechanism in the first phase is solved by the optimal trajectory planning method. 2.2 3-dof Analytical Model and Equation of Motion in the First Section. The analytical model of the 3-dof biped walking mechanism used for the optimal trajectory planning in the first section is shown in Fig. 3. Notation ui is the input torque at joint i , l i is the i-th link length, mi is the i-th link mass, ai is the distance of the mass center of the i-th link from the joint i , and I i is the inertia moment of the i-th link about the mass center. Using Lagrange\u2019s equation, the equation of motion with respect to u1 , u2 , and u3 is derived as follows: F M 11 M 12 M 13 M 22 M 23 Sym M 33 G H u\u03081 u\u03082 u\u03083 J 1F 0 c12 c13 0 c23 AntiSym 0 G \u2022H u\u03071 2 u\u03072 2 u\u03073 2 J 1H K1 K2 K3 J 5H u12u2 u22u3 u3 J (1) where M 115I11m1a1 21~m21m3"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure4.16-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure4.16-1.png",
+ "caption": "Figure 4.16. Simple relative motion of a sliding pin of a mechanism.",
+ "texts": [
+ "52), we find VAG= ~vGA = V AO = 0) X X= 10j ft/sec, aAG= ~aGA=aA0 =rox(roxx)= ~5ift/sec2, (4.54c) wherein x = 20i ft and ro = ( 1/2) k rad/sec in accordance with Fig. 4.15. Of course, m=O in (2.30). Thus, substitution of (4.54a) and (4.54c) into (4.54b) determines the velocity and acceleration of the ball apparent to the rider: v BA = ~ 15i ~ 14j ft/sec. anA= ~32j + 5i ft/sec 2. (4.54d) 266 Chapter 4 Since the frames are parallel, the results may be referred to either basis set with ik = Ik. 0 Example 4.9. A pin P shown in Fig. 4.16 is constrained to move in a cir cular groove milled to a radius of 3ft in a large rectangular plate. The pin also slides in the straight slot of a slanted link mechanism which is moving toward the right with a constant speed of 5 ftjsec. The slot makes an angle of 30\u00b0 with the horizontal drive shaft, as illustrated. Find for the instant shown the velocity and the acceleration of P relative to the plate and to the link. Solution. Let the frame f/J = { F; I, J, K} be fixed in the plate, and let aPF= apo\u00b7 (4.55b) Each of these vector equations involves two unknown vector quantities; hence, additional information about their components must be furnished in order to solve ( 4.55b) for the unknown vectors. This is done by considering the nature of the motion of the pin in the separate frames. The observer in f/J sees P move on a circle of radius R = 3 ft whereas the observer in
= { F; ik}. Find the velocity and acceleration of pin A in frame r/> when the link is in the configuration shown. What are the velocity and acceleration of A relative to B at this instant? 4.34. Suppose that the mechanism described in Example 4.9 has the initial position shown in Fig. 4.16. Find the velocity and acceleration of the pin P relative to the frames r/> and qJ at the instant t = 0.4 sec. 4.35. A pin P controls the motion of two slotted links so that they move on guide rods at right angles to one another. At the instant illustrated, link A has a speed to the right of 15 cm(sec and is decelerating at the rate of 50 cmfsec2. Concurrently, the link B is moving upward with a speed of 20 em/sec and is slowing down at the rate of 75 cmfsec each second. What is the radius of curvature of the trajectory of P at this instant"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003972_robot.2006.1642071-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003972_robot.2006.1642071-Figure2-1.png",
+ "caption": "Fig. 2. Simultaneous control of motion and deformation in 1D",
+ "texts": [
+ " In this section, we formulate the simultaneous control of motion and deformation of the soft material. First, we model the soft object using particle based model [9]. We use linear mass-damper-spring components. Next, we formulate the system including the control laws. Finally, we analyze the stability of the system by the Rauth-Hurwitz Criterion. A. Description of motion and deformation of soft material along the x-axis In this paper, we consider a simultaneous control of a soft object as shown in Figure 2. The soft object moves along the x-axis, and includes two positioned points and two manipulated points. The positioned and the manipulated points are mass points. We can control the motion and the deformation of the soft object by regulating all the positioned points to respective desired points. In general, physical parameters of a soft object, especially viscosity, is unknown. Hence, it is difficult to use a feedforward control as a control law. We use a feedback control as a control law. Concretely, we use PID control for the positioned points",
+ " In this model, we use linear mass-damper-spring components and consider the motion and deformation of the soft object along the x-axis. Let Pi represent the i-th mass point. Let xi and vi represent the position and velocity of Pi at time t, respectively. Note that the number of masses is not serialized along the x-axis to utilize the symmetry of the model in analysis. In Figure 4, P0 and P2 are manipulated points, while P1 and P3 are positioned points. We regulate the positioned points to the respective desired points by controlling the manipulated points to control the motion and the deformation simultaneously, as shown in Figure 2. Let kij and bij be the elastic and viscosity coefficients, respectively, of the soft interface between i-th and j-th masses, and mi represent the mass of Pi. Additionally, let Lij be the natural length of the soft interface between i-th and j-th masses. Physical parameters of the soft interface and mass points are time-invariant and positive. By varying the physical parameters, the model can be used to represent various cases. For example, when we use a high stiffness value as a parameter k13, the model describes the case of a soft-fingered robotic hand grasping a rigid object as shown in Figure 5"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002283_20.917638-Figure6-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002283_20.917638-Figure6-1.png",
+ "caption": "Fig. 6. Power spectra of velocity measurement between disk B and the slider (SD).",
+ "texts": [
+ " The FH was numerically calculated by the Computer Mechanics Laboratory (CML) Air Bearing Design Code and plotted as a function of disk RPM as shown in Fig. 5(b). Before measuring the repeatable FHM of the slider, we evaluated the flyability of the slider by the \u201cspin-down\u201d test measuring friction and AE and also measuring the velocity response between the slider and disk (SD). From the velocity response with disk B for different RPM, we saw that the slider strongly oscillates if the disk velocity is less than 20.6 m/s. Fig. 6 shows the frequency domain data of single SD velocity time captures from 12 to 22.3 m/s (increasing air-bearing resonant amplitudes as RPM decreases). Even at 20.6 m/s, the bursts in the velocity history indicate that the slider did not steadily fly over disk B. In fact, the velocity output of the LDV is much better than the displacement output in detecting this kind of small bursts. Similarly, below 20.6 m/s there were very strong AE signals, which saturated our data acquisition system even with a very low amplifier gain, and high friction values were also recorded. From both the \u201cspin-down\u201d flyability test and the measurement of the time histories of the velocity of the slider flying with disk A (SD) for disk RPM ranging from 10.3 to 17.2 m/s, it was observed that the slider could steadily fly with disk A at and above 12 m/s. Fig. 7 shows the frequency domain of SD of a single time capture with the same scaling as in Fig. 6. The air-bearing resonance at 12 m/s, which results in a large FH variation, can be seen. We measured the responses of all three sliders mentioned previously, and they all showed very similar phenomena. During the experiment, we found the strong oscillations of the slider are not very repeatable, therefore they cannot be easily observed in the time domain with the trigger. If the air-bearing resonance is not clear in the time averaged frequency domain but appears strongly in the frequency averaged data, then the excitation of the air-bearing is nonrepeatable"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003502_095440904322804439-Figure15-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003502_095440904322804439-Figure15-1.png",
+ "caption": "Fig. 15 The three different wheelsets analysed with the FEM model",
+ "texts": [
+ " An elastic\u00b1plastic material behaviour (and therefore the actual stress\u00b1strain diagram) could also be considered with this model, but the corresponding results differ very little from those obtained from the linear elastic hypothesis; the plastic zones are in fact present only for high interference values, but they are always very small and located at the wheel seat chamfer, with a negligible effect on the press-\u00aet curve. All the analyses for the press-\u00aet curve determination have therefore been carried out under the linear elastic hypothesis. Three different wheelsets have been examined, named Sao Paolo, United Kingdom and Fiat Ferroviaria, shown in Fig. 15. For each wheelset, a range of possible interferences has been considered, due to the machining tolerance of the axle and wheel. The press-\u00aet operation was simulated constraining one end of the axle in its longitudinal direction and applying a displacement at the wheel, as shown in Fig. 16. The sum of the reaction loads at the constrained end represents the press-\u00aet load, whose value is expected to increase with the wheel displacement, due to the increasing friction-resistant load. Proc. Instn Mech"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003657_j.cma.2005.02.033-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003657_j.cma.2005.02.033-Figure10-1.png",
+ "caption": "Fig. 10. 3-DOF RPR planar parallel robot.",
+ "texts": [
+ " For 12 s of simulated mechanism motion, the solution time for the indirect coordinate equations is reduced to less than half the time required to solve the equivalent joint coordinate equations. The time required to formulate the motion equations is also reduced when indirect coordinates are used. Note that the formulation time is less important than the solution time since, in a symbolic approach such as this, the equations are only formulated once prior to subsequent simulations\u2014 unlike in a numerical approach where the equations are re-assembled at each time step of a forward dynamic simulation. The two-dimensional, 3-DOF parallel robot shown in Fig. 10 has three revolute-prismatic-revolute chains acting in parallel on the end effector, body 7. The three chains are driven by rotational motors at joints A, B, and C. This configuration is known [17] as the 3-RPR planar parallel mechanism (PPM), where the underlined letter indicates which joint is driven in each kinematic chain. The linear graph of the 3-DOF parallel robot is shown in Fig. 11. A planar joint pl28, which allows 2 translational and 1 rotational DOF, has been added so that the end-effector variables can be included directly in the dynamic equations"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000482_39.666569-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000482_39.666569-Figure2-1.png",
+ "caption": "Figure 2. The da-qa frame",
+ "texts": [
+ " 1, the IEEE Power Engineering Review, May 1998 63 point A has a low PF. It is possible to improve this PF, maintaining the same active power, by moving the pointA to B location (optimal PF). In this case, the magnetization current is reduced (I@ < I@). The stator current is then reduced leading to copper losses decrease (i2t). Moreover, magnetization current decrease leads also to iron loss decrease. Finally, loss balance can be obtained approximately leading then to a maximum efficiency. Optimization Algorithm: According to Figure 2, the PF is expressed in the d-q frame by In the da-qa frame, it becomes The following relationship is then deduced. Isdc = \u2018qa \u2018g9-I (3) Therefore, the PF optimal value is reached when equation cp = \u2018pa is (4) Going back to the d-q frame leads to the basic equation of the opti- insured. In this case, (3) could be replaced by I,, = K,Isq,; KO = tgcp-\u2019 mization algorithm (\u2019control variable). where is called the e~ciency-optimizationfactor (EOF). As it is shown by (6), one main advantage of the proposed method is that it is insensitive to parameter variations contrary to the loss-minimization factor (LMF) presented in [3]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001280_0022-0728(94)03651-i-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001280_0022-0728(94)03651-i-Figure4-1.png",
+ "caption": "Fig. 4. Cyclic voltammograms obtained with a Pf-CP(BQ)E in (A) the base solution of pH 7.0 and (B) a solution containing 10 mM nicotinic acid. Scan rate, 2 mV s 1.",
+ "texts": [
+ " The effectiveness of the compounds as mediators may depend on such factors as their reactivity with the enzyme in the bacterial membranes and the permeability of the membranes to the compounds. Since BQ is as effective as PMS as the mediator and is more stable than PMS, we used BQ as the mediator in the following experiments. Dialysis-membrane-covered Pf-modified CPEs containing BQ (Pf-CP(BQ)Es) were prepared in a similar manner to that reported [18] for the preparat ion of enzyme-modified CPEs containing BQ. Pf-CP(BQ)Es containing 3% w / w BQ were used unless stated otherwise. Fig. 4 shows cyclic vol tammograms recorded with a Pf-CP(BQ)E in (A) the base solution and (B) the base solution containing 10 mM nicotinic acid. The Pf-CP(BQ)E produced cathodic and anodic waves starting from +0.04 V and +0.15 V respectively in the base solution, which are attributable to the redox reaction of BQ entrapped in the immobilized Pf layer between the electrode and the dialysis membrane as was confirmed previously in the case of a CPE containing BQ with immobilized oxidoreductase behind a dialysis membrane [19]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003534_j.talanta.2006.08.037-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003534_j.talanta.2006.08.037-Figure4-1.png",
+ "caption": "Fig. 4. Chemiluminescence response from the reaction of manganese(IV) ( ( o",
+ "texts": [
+ " The se of 3 mol L\u22121 formaldehyde produced the greatest chemiluinescence response above the background: a 500-fold increase n signal intensity (Fig. 3) compared to responses obtained when nalyte and carrier solutions contained no formaldehyde. Yet, espite this notable enhancement in manganese(IV) chemiluinescence intensity, the reactions were still not visible to the aked eye in a darkened room. An increase in both signal and background intensity was also bserved using higher orthophosphoric acid concentrations to ilute the stock manganese(IV) solution (Fig. 4). For example, he use of 6 mol L\u22121 orthophosphoric acid gave approximately 12-fold increase in signal (compared to the 3 mol L\u22121 diluion used in previous chemiluminescence studies [1\u201311]), and he reagent remained stable for over 4 months without preciptating. These improvements in chemiluminescence response nd reagent stability are possibly due to the stabilising effect f orthophosphoric acid on the manganese dioxide particles in olution via adsorption to the particle\u2019s surface [15,19]. Howver, concentrations above 3 mol L\u22121 orthophosphoric acid were enerally avoided due to the viscosity of the solutions and the arge increases in background signal, which compromised low evel detection"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002168_s0039-9140(03)00075-4-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002168_s0039-9140(03)00075-4-Figure1-1.png",
+ "caption": "Fig. 1. (A) Scheme of the flow cell used in the measurements (see test for description); (B) Picture of the flow cell placed into the sample compartment of the luminometer. (a) Stainless steel piece; (b) y; (c) inlet and outlet; (d) methacrylate piece; (e) optical fiber.",
+ "texts": [
+ "1 ml of a phosphate buffer solution contain- ing 20 mg of acrylamide, 4 mg of bis-acrylamide and 8 mg of ammonium persulphate (as a reaction precursor) were mixed with 0.1 ml of the GOx-FS solution. Dissolved oxygen was eliminated by bubbling nitrogen through the solution. The cocktail was spread on a 0.5 mm hollow made in a glass film (20 /9 /0.1 mm), covered with a Mylar film and a glass film, and irradiated with the UV-lamp (254 nm) for 50 min. The film was then stored in the phosphate buffer solution at 4 8C. The flow cell was designed in our laboratory (Fig. 1A). The main part of the cell (a) was a stainless steel piece (2 /2.5 /2 cm) with a hollow (0.5 /1.5 /0.3 cm) in which the sensor film (b) is fixed with a holed Mylar film (c). The flow cell was covered with a methacrylate piece (d) containing two stainless steel tubes (2 mm, outer diameter) for circulation of the fluid in the cell; the space between tubes was just wide enough for the optical fiber termination (Fig. 1B). Pieces (a) and (d) were joined by means of four screws and a silicon washer (e) to avoid fluid loss. The sensor had a 225 ml capacity. The phosphate buffer solution flowed across the flow cell at 0.7 ml min 1 and the fluorescence intensity began to be monitored at lexc /490 and lem /520 nm (I0 being the initial fluorescence intensity of the film). Three hundred microlitres of the sample (or glucose standard solution) were injected and a transient signal obtained, Imax being the fluorescence intensity at the maximum",
+ " 2A shows how the fluorescence intensity of the sensor changes when the flow-cell is fed in a continuous mode with solutions of different glucose concen- tration; as the glucose concentration increases the rate of the intensity variation with time increases but the maximum intensity changes very slightly; if a random time t is considered after the beginning of the glucose feed and before the maximum is reached, the intensity at this time (It) changes with the glucose concentration. When glucose solutions are injected in FIA mode (discrete sample volume) two opposite effects take place: (1) the increase in fluorescence intensity due to the enzymatic reaction; and (2) the decrease in intensity due to dilution of glucose and regeneration of the enzyme. These opposite effects give a FIA-like peak in which the analytical parameters described in Section 2.6, change with glucose concentration (Fig. 2B). Prior to the system shown in Fig. 1, two other flow cell systems were designed. Firstly, a system (Fig. 3A) consisting of a methacrylate piece (a; 7.7 /5 /0.4 cm) with a central hollow (b; 1.1 / 0.5 /0.5 cm; 275 ml volume) and two lateral orifices (c and d; 0.5 mm diameter) for sample inlet and outlet. Two Mylar films (e, f) fixed with silicone closed the central hollow; the rear film (e) contained the polyacrylamide-GOx-FS sensor film (g). Finally, a reflecting mirror (h) was fixed to the back part of the system to increase the optical path-length"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001511_978-1-4612-1416-8_9-Figure9.2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001511_978-1-4612-1416-8_9-Figure9.2-1.png",
+ "caption": "FIGURE 9.2. (a) Controlled planar body with a pendulum attachment; (b) Controlled pla nar body with an extending pendulum attachment. The length of the extensible pendulum is ax, where x is the x-coordinate of the hinge point connecting the two bodies.",
+ "texts": [
+ " The nonvanishing of the curvatures associated with both the 3 x 3 inertia tensor of the unreduced system and the 2 x 2 inertia tensor of the reduced system imply that there is no change of coordinates such that the dynamical dependence on input accelerations is eliminated and the dynamics of the configuration variables \u00a2 and 1/1 are also decoupled. Whether one can simply eliminate the input accelerations by a choice of coordinates in which there is inertial coupling of the \u00a2 and 1/1 dynamics remains for the moment an open question. Example 9.3.2 (Controlled planar body with pendulum attachment) Here we consider a pair of rigid bodies which are connected by a simple frictionless single degree-of-freedom hinge as illustrated in Figure 9.2(a). One of the bodies (the larger one depicted in the figure) is assumed to have actuators allowing its motion in the plane to be controlled to follow any prescribed smooth path. No actuation is applied directly to the pendulum, and hence it moves entirely under the influence of gravity and motion of the controlled body. Take as generalized coordinates for the system x (the horizontal displacement of the large body), y (the vertical displacement of the large body), and e (the angular displacement ofthe pendulum from the vertical, downward pointing configuration)",
+ " It is also easy to verify that the vanishing conditions of Theorem 9.3.1 are satisfied. Indeed, the reduced inertia tensor, M = h, is a scalar, and hence the Riemannian curvature is trivially zero. The input connection f li}, i, j = 1,2 is zero, and hence the input curvature is also zero. Example 9.3.3 (Controlled planar body coupled with extending pendulum at tachment) The concluding example treats another system for which the curvature vanishing conditions of Theorem 9.3.1 are not satisfied. The mechanism depicted in Figure 9.2(b) is similar to the previous example, with the significant difference being that we assume there is an internal mechanism which causes the length of the pendulum attachment to depend on the x-coordinate of the body. Specifically, we assume the length of the pendulum is ax, where a > 0 is some fixed constant. We assume again that the pendulum is attached by a frictionless hinge. To simplify the discussion (and with no loss of generality) we idealize the model so that the pendulum is comprised of a point mass mb and a massless linkage between the point mass and hinge"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003893_0301-679x(83)90004-x-Figure10-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003893_0301-679x(83)90004-x-Figure10-1.png",
+ "caption": "Fig 10 Universal joint with rubber-metal laminated bushings",
+ "texts": [
+ " A typical joint has two yokes attached to the shafts to be connected and a spider with four trunnions, each pair of the trunnions rotationally engaged with its respective yoke and the axes of two pairs in one plane and orthogonal. Both sliding and rolling friction bearings are used in universal joints, and for both types their use in these joints is one of the most trying possible applications because of the oscillatory character of the motion. Again, the application of thin-layered rubber-metal laminates for U-joint yoke bearings (Fig 10) ~l seems to be a logical solution of the problem. Detailed calculations have shown that using the types of laminates discussed in the first part of this paper, with one-layer thickness of 0.01-0.1 mm, only a small fraction of the load-supporting area of the trunnion is needed for transmission of the rated load for a given size of the joint. Reduction of this area greatly reduces the shear stiffness of the laminated bearings. The greatest advantages of universal joints with rubber laminated bearings are: elimination of lubrication and sealing devices; elimination of wear and backlash in the connection; very substantial attenuation of radial forces and/or vibrational excitations transmitted through the connection"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002374_naecon.1994.332886-Figure12-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002374_naecon.1994.332886-Figure12-1.png",
+ "caption": "Figure 12",
+ "texts": [
+ " AIRCRAFT SPOILER (1988 - ) This prototype subsystem was built specifically for use in a commuter aircraft spoiler actuation application. It was designed with assistance from the aircraft manufacturer to fit the aircraft envelope. Extensive bench testing was performed on the EMA in a simulated aircraft installation with al l performance criteria successfully verified. The use of 270 VDC allowed lower current levels and higher reliability switching devices. A photograph of this EMA i s shown in Figure 12. 1343 SYSTEM ADVANCES - Brushless DC motor, 270 VDC power supply DIGITAL MISSLE CONTROL (1990-) This prototype subsystem was designed to accomplish steering of a missile system. This EMA incorporated a microprocessor driven control system which allowed fault management. The overall subsystem predicted reliability was increased along with heat management. SYSTEM ADVANCES - Digital control, MIL-STD1553 data bus interface, digital slaving. LARGE AIRCRAFT AILERON (1990-) This long term development program includes several phases of development ranging from feasibility studies to fabrication of flight quality demonstrators"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003704_robot.2003.1241965-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003704_robot.2003.1241965-Figure1-1.png",
+ "caption": "Figure 1: Model of compass-like biped robot",
+ "texts": [
+ " The potential energy in walking down the slope changes the robot\u2019s kinetic energy. The robot loses energy when the swing leg contacts the ground. In the c a e of stable gait, it keeps a balance between the energy lost at the ground impact and the energy s u p plied by potential energy. In this study, the stability and dynamics around the fixed point before and af - ter period-doubling bifurcation are investigated. Especially, we focus on the stored energy of the robot and the rate of change of this energy 2 Compass-like Biped Model Figure 1 shows the model of compass-like biped robot. In this figure, m is the mass of each leg. 1 is the leg length, and a is the distance from the tip 0-7803-7736-2/03/$17.00 02003 IEEE 2478 of leg to the center of mass of it. I is the moment of inertia about its center of mass. 8,, and Os, are the angles of stance leg and swing leg with respect to the horizon respectively. a is the inter-leg angle. y is the angle of slope. The gait consists of the swing phase and the transition phase. During the swing phase, the contact point +of stance leg is not off at any time"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001419_robot.1991.131938-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001419_robot.1991.131938-Figure5-1.png",
+ "caption": "Fig. 5 : First Method to Select a Support Trajectory of Circling Gaits.",
+ "texts": [
+ " Since the crab walking gait is a special case of circling gaits, the four wave-circling gaits should possess a similar feature. In other words, for a given turning center, if the stabilit,y margin at, ,B = 3/4 is zero, it should be more stable when /3 > 3/4. Based on this inference, two st,rat,egies for the selection of support trajectories are developed. The distinguishing feature of the first, strategy is that the support trajectories of the four legs pa.ss through their workspace centers. Referring to Fig. 5 . since the largest leg angular stroke 91 is less than the largest leg stroke + 4 , leg 1 has less adjusta.bility and the support trajectory of leg 1 is selected first. As shown in Fig. 5 , the middle portion of 91, the solid arc Tis;, is chosen to be the support trajectory of leg 1. At the moment right before leg 2 is placed, leg 1 is a t the position of Ml. In order t o have a zero stability margin a t this moment, leg 4 should be a t the position of M4, which is the intersection of the straight line passing through M1 and the gravity center with the circular path of leg 4. By using M4 as a reference point, the support trajectory of leg 4 can be selected, as shown in Fig. 5 . I t is possible that the selected support trajectory of leg 4 is outside the workspace of leg 4 or that the straight line M ~ M I and the circular path of leg 4 do not intersect. Under these circumstances, the turning gait is considered to be unstable. Similarly, we can select the support trajectories of leg 2 and leg 3. This strategy can be also applied to +y type, - z type and --y type wave-circling gaits. In the second strategy, the two support trajectories with larger available leg angular strokes do not necessarily pass through their workspace centers"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002374_naecon.1994.332886-Figure3-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002374_naecon.1994.332886-Figure3-1.png",
+ "caption": "Figure 3",
+ "texts": [
+ " Flow direction and rate is accomplished through the positioning of variable angle swashplate. The positioning of the swashplate i s governed by an internal control loop which receives the control error input, measures swashplate position and produces control flow to one of two stroke control pistons. An integral fixed displacement boost pump, used to supply control flow and maintain minimum actuator pressure can also be used. Maximum discharge pressure capability of the servopump has been well proven at 5000 psi. A schematic of the servopump is shown in Figure 3. ELECTRIC MOTOR - Since the servo control of the lAPTM i s performed within the servopump detailed above, the only requirement for the electric motor i s to rotate the servopump at a fixed speed and direction. This requirement can be accomplished with either AC or DC motors. The preferred choice i s AC as this provides a simpler, more readily available design. In addition, AC power minimizes EM1 generation and it's possible degradation of control signalling. In an aircraft system where DC motors are preferred, the lAPTM can be configured with a brushless DC motor and motor controller designed to maintain a relatively fixed speed"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000497_a:1008966218715-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000497_a:1008966218715-Figure9-1.png",
+ "caption": "Figure 9. The field of view, the clustered regions and the obstacle regions.",
+ "texts": [
+ " After updating the parameters of the associated obstacle regions by using the corresponding clustered regions, we now move on to delete the obstacle regions that are in the field of view and not associated with any of the clustered regions. The field of view is the scanning range of the laser scanner where the distance of view depends on whether a clustered region Ri exists in the direction of view. If Ri exists in the direction of view, then the distance of view is the distance up to Ri . Otherwise, it stretches up to the detection limit of the active circle dc. An example of the field of view is shown in Fig. 9. As shown in Fig. 9, the obstacle regions M3 and M4 are located in the field of view and they are not associated with any of Ri \u2019s. Consequently, they must have been moved to another location and must be deleted from the map. The obstacle regions M1 and M2 are not associated with any of Ri \u2019s either, but they are not deleted from the map because they are outside of the field of view. In other words, we do not know whether M1 or M2 has been moved or not, because they have not been currently detected. The obstacle region M7 is associated with R4, but it is not updated because part of it is located outside of the field of view",
+ " The angle interval of Mk is the interval of directions along which the laser range finder detects the obstacles in Mk . As shown in Fig. 10, the angle interval is determined from the major eigenvector of Mk . Its major eigenvector is described as e\u0304k \u2212 s\u0304k , where e\u0304k and s\u0304k represent its start and end positions in the sensor coordinate frame. The angle interval of Mk is then determined as [6 s\u0304k, 6 e\u0304k], where s\u0304k = m\u0304k + \u03bb\u03041k \u03c6\u0304k \u2212 pc, e\u0304k = m\u0304k \u2212 \u03bb\u03041k \u03c6\u0304k \u2212 pc, and pc is the center position of the mobile robot. As shown in Fig. 9, the angle intervals of the obstacle regions such as M1 and M7 range outside of [0, 270] and their parameters remain unchanged. On the other hand, the angle interval of R1 fully covers that of M2 and the distance of M2 is longer than the that of R1. Consequently, M2 is located behind R1 and its parameters remain unchanged. Finally, if Ri is not associated with any of the existing Mk\u2019s, then a new obstacle region is created with Ri and is included in the map. For example, R2 in Fig. 9 is not associated with any of Mk\u2019s, and a new obstacle region is created with R2. The object position p j determined from dead reckoning and measured distance value l j is bound to have uncertainty, which may cause mismatch between the map and the real environment. In general, there are two types of uncertainty sources: one is the noise inherent in the measured data, and the other is the mechanical aspects of the mobile robot such as slippage and upsetting events. The gaussian random noise inherent in the object position p j is essentially cancelled out in the presented algorithm because all of the object positions included in the same clustered region Ri are averaged to determine the stochastic parameters of Ri "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001850_jsen.2003.814649-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001850_jsen.2003.814649-Figure2-1.png",
+ "caption": "Fig. 2. Photo image of fabricated three electrode cell for glucose and its cross section view. (a) Photo image. (b) Cross section view.",
+ "texts": [
+ " A Conventional Ag/AgCl (3 M KCl) electrode was used as a reference electrode during the potential measurements and the electro-deposition of platinum and enzyme layers. Electrochemical measurements were carried out in PBS (phosphate buffered saline) solution containing 0.1 M Na HPO , 0.15 M NaCl, and 0.1 g/l NaN (pH 7.4). Potentials were measured under open-circuit condition. Performance evaluation of the glucose sensors was carried out with the on-chip plasma-treated Ag/AgCl reference electrode without any additional electrode. Fig. 2 shows the photo image and its cross section diagram of fabricated sensor array. The order of the electrode placement was, from the center, working, counter, and reference electrodes. Uncompensated solution resistance can be minimized if the reference electrode is positioned to the nearest of working electrode. However, in this paper, it was placed at the outside of the counter electrode to avoid the electrical short to the working electrode due to the dissolved silver ions. The area of working, counter, and reference electrode was 0"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003734_ip-b:19830027-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003734_ip-b:19830027-Figure4-1.png",
+ "caption": "Fig. 4 Explanation of slip derivation (eqn. 7)",
+ "texts": [
+ " If the rotor moves in a helical fashion, then the slip of the rotor related to the kl harmonic of the magnetic field is expressed by the equation ktt \" vxk vzli (7) i l k where vx and vz are rotor speeds in the x-and z-directions and vxk = \u2014 2rxfe/and vzU = \u2014 2Te/,/are speeds of the kl harmonic in the x- and z-directions. Eqn. 7 can be derived in two different ways. One of them, given in Reference 1, is as follows: If the rotor moves with asynchronous speed in relation to the kith field harmonic, it means that the field of kith harmonic varies for each point on the rotor surface. Thus, for the moving point P[Xi(t), zt(t)] on the rotor surface (Fig. 4), we have: JSz(t,X,z) = (6) ^ i , z i ) = 5mWexp / \\tot+ \u2014 xt +\u2014 zx [ \\ Txk Tzl = variable (8) IEEPROC, Vol. 130, Pt. B, No. 3, MA Y1983 187 Hence u>t n H (9) where a(t) is the angle between point P and the wavefront of the kith harmonic. Differentiating each side of eqn. 9, we obtain: CO + Vx+ Vz = Txk Tzl (10) where vx, vz are the rotary and linear rotor speeds, respectively, and dt is the angular speed of point P in relation to the kith field harmonic. Similarly, as in the theory of conventional induction motors, we can write Thus, from eqns"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002362_itsc.2003.1252673-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002362_itsc.2003.1252673-Figure4-1.png",
+ "caption": "Figure 4 Reference point of vehicle",
+ "texts": [
+ " Since this procedure isreversible thus it can be applied in parallel parking problem Furthermore, this procedure is simplified the steering angles to the minimum radius condition. Effectively, according to the vehicle steering scenario described at the former kction two identical circles with tangent point can be formed. For example, a vehicle moves backward from A to B following a path formed by two circular arcs tangentially connected to each other. Supposing B i s parking bay and A is starting position, thereby parallel parking is achieved (see figure 4). The locations of circle center are depending on the detected parking space and the lateral displacement from the aside car. There are several conditions have to fulfill in order to have a collision-free motion (see figure 5) : 1. The length L must be larger than radius of the circle C,. . 2. Thecar mustatacomect position when begin to parking. The right position is determined by AxandAy. 3. The tuning point AT is depending on different value of Ax and hY. In our methodology the vehicle is always track to the tangential circles"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003008_1.1757488-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003008_1.1757488-Figure4-1.png",
+ "caption": "Fig. 4 Twist disclination loop of radius a0 coaxial to a cylinder. Distribution of virtual twist disclination loops is shown on cylinder surface.",
+ "texts": [
+ "u z5h r5a0 1 2h a0 J**~1,1;1 !u z5h r5a0 1 2h2 a0 2 J**~1,1;2 !u z5h r5a0D G , (34) where rcore is the core cutoff radius of the loop. The first term in Eq. ~34! is the energy of the prismatic dislocation loop in an infinite medium and the second term is the interaction energy between the prismatic loop and the free surface. 4.3 Twist Disclination Loop Coaxial to a Circular Cylinder. Consider a twist disclination loop of radius a0 placed coaxially in an infinitely long elastic circular cylinder of radius r0 as shown in Fig. 4; the coordinates of the loop center are ~0,0,0!. On the free surface of the cylinder, the following boundary conditions for the stress field must be fulfilled: sr jur5r0 50, j5r ,w ,z . (35) The twist disclination loop has the stress component srw ~see Eqs. ~10!! contributing to the conditions Eqs. ~35!. We present the resulting field of the twist disclination loop in the cylinder in the form of Eqs. ~15!. The additional field ipi j is produced by the virtual twist loops distributed in the manner shown in Fig. 4. All virtual loops have the same radius r0 . Then the boundary conditions Eqs. ~35! can be rewritten in terms of the distribution function f (z0) of the virtual twist disclination loops: Transactions of the ASME 16 Terms of Use: http://www.asme.org/about-asme/terms-of-use Downloaded F 2 Gv 2 sgn~z !J~2,2;1 !ur5r0 1E 2` ` f ~z0!F2 Gv 2 sgn~z 2z0!E 0 ` J2~k!J2~k!expF2 uz2z0u r0 kGkdkGdz050. (36) Applying the Fourier transformation to Eq. ~36!, one can find the Fourier transform of the distribution function f\u0302 "
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002455_j.precisioneng.2004.03.003-Figure9-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002455_j.precisioneng.2004.03.003-Figure9-1.png",
+ "caption": "Fig. 9. Structure of experimental apparatus for measuring NRRO.",
+ "texts": [
+ " Additionally, in the case of the same value of mutual diameter differences of balls, a larger number of balls makes the fc component smaller. However, if the mutual diameter differences of balls are minified by 0.01 m, the contributing ratio to reduce the expected value of the fc component is 20% for Z = 8 and 17\u201318% for Z = 10. Here, the contributing ratio is defined as the diminution of the expected value of fc component divided by the diminution of the mutual diameter differences of balls in a production lot. Fig. 9 shows an experimental apparatus for investigating the influence of location of balls on the fc component [2]. As the NRRO measuring device methods for single ball bearing, the following techniques are reported. The first is a measurement technique of radial runout of the spindle axis which is constructed by the rolling bearing to be measured and another rolling bearing [9,10]. The second is an imitative technique of the revolution error measurement method for rolling bearings described in JIS B 1515, using aerostatic Oldham coupling [11]"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000481_j.1470-8744.1999.tb01149.x-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000481_j.1470-8744.1999.tb01149.x-Figure1-1.png",
+ "caption": "Figure 1 Schematic design of the BChE\u2013ChO sensor",
+ "texts": [
+ " After removal of the membrane, the solution was added to a mixture consisting of a 4-aminoantipyrine} Labels : a, platinum wire ; b, glass ; c, Teflon cap ; d, HEMA\u2013VCA membrane. phenol}peroxidase mixture ; the activity was calculated from the A500 value. Free BChE activity was determined spectrophotometrically by using a kinetic method that followed the increase in A405 due to 5-thio-2-nitrobenzoate produced by the reaction between 0.4 mM 5,5\u00ab-dithiobis-(2-nitrobenzoic acid) and thiocholine formed in the enzymic hydrolysis of butyrylthiocholine iodide [0.335 mM in phosphate buffer (pH 7.0)]. As shown in Figure 1, the amperometric transducer consisted of a platinum wire (0.5 mm diameter) sealed in a glass tube (5 mm diameter) and polished with alumina powder to ensure a flat surface. The HEMA\u2013VCA membrane containing the two immobilized enzymes was placed on the flat electrode surface and fixed with a Teflon cap having a 3 mm hole. The good mechanical properties of the wet membranes and the fixing system used allowed their easy replacement and also the possibility of using them again. When not in use the membranes were stored at 4 \u00b0C in a suitable buffer or in the dry state"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001305_0924-0136(94)01333-v-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001305_0924-0136(94)01333-v-Figure1-1.png",
+ "caption": "Fig. 1. The shape of the panels in the present study (dimensions: mm).",
+ "texts": [
+ " (i) Can the tensile behaviour of the virgin material be used for prediction of the yield strength of a panel pressed in the same material? (ii) What does replacement of a mild steel sheet by a high strength steel sheet mean in terms of strain level in the panel? (iii) How can the stiffness of the panel be characterized? (iv) On what does the dent resistance of the panel depend? The present investigation has been carried out in order to answer the above questions. The panels pressed in this study are a small-size version of the roof panel of an existing car body and are double-curved, Fig. 1. The yield strength of the panel is to be determined at its centre by the drawing of tensile specimen cut at 0 \u00b0, 45 \u00b0 and 90 \u00b0 to the original rolling direction, whilst the 0924-0136/95/$09.50 \u00a9 1995 Elsevier Science S.A. All rights reserved. SSDI 0 9 2 4 - 0 1 3 6 ( 9 4 ) 0 1 3 3 3 - V stiftness of the panel at its centre is to be measured using a flat-headed punch with a diameter 100 mm. The dent depth is to be measured at the centre of the panel also, in this test a hemispherical punch with a diameter of 100 mm being used",
+ " Asnafi / Journal of Materials Processing Technology 49 (1995) 13-31 15 and ~2 = [ 1 2 ( 1 - v2)] 1/2 ~2 ( R ) , (5) where R is the radius of the sphere, P is the concentrated load at the apex, E is Young's modulus, t is the shell thickness, v is Poisson's ratio and ~ is the angle between the centre and the edge of the sphere. Furthermore in this figure, ~5 is the deflection at the apex. Note that 22 in Eq. (5) and Fig. 2 is a measure of how large the shell segment is! The greater the value of ~, the larger is the sphere segment. a spherical shell. Depending on which side of the rectangle is used in the approximation, different values of ~2 are obtained: see Fig. 3 and compare it with Fig. 1! Combining Eqs. (2), (3) and (4) p . ~ P - 2 ~ E t a (6) The maximum load that will be used in the stiffness tests is 125 N. Substituting into Eq. (6) this value, the nominal values of R1 and R2 (Fig. 1), E = 20.104 N/mm 2 and t = 0.7 mm, P* = 0.334. which gives the encircled zone in Fig. 2, applicable in the present approximated case. Knowing the different values of 2 2 (Fig. 3), the applicable load~leflect ion zone in the present approximated case, (Fig. 2), and the shape of the load-deflect ion curve in this zone, it is assumed that over this interval and for the present panel p , = C(6/t) m (7) N. Asnafi / Journal of Materials Processing Technology 49 (1995) 13-31 17 in which C and m are different constants"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001553_s0045-7825(99)00329-1-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001553_s0045-7825(99)00329-1-Figure2-1.png",
+ "caption": "Fig. 2. Illustration of line of singularities and two branches of generated surface.",
+ "texts": [
+ " ; 3) are formed by respective elements of matrix A. The simultaneous equality to zero of the three determinants represented above means D2 1 D2 2 D2 3 0; 10 that yields the following equation F2h ut;wt;wh 0: 11 Step 3: The sought for limiting line Lh on surface Rh is determined as follows: rh rh ut;wt ; f2h ut;wt;wh 0; F2h ut;wt;wh 0: 12 Step 4: Using the coordinate transformation from Sh to S2, we may determine E2, the line of singularities on worm-gear tooth surface R2. Singularities of R2 can be avoided by limitation of dimensions of R2. Fig. 2 shows line E2 of singularities on surface R2 that is simultaneously the envelope to contact lines on R2 and the edge of regression; E2 is the common line of two branches of R2 as well. Note: It was mentioned above that for determination of F2h 0 (see Eq. (11)) it is necessary to use Eq. (10) as the requirement of equality to zero of three determinants: D1, D2, and D3. In most cases, it is suf\u00aecient to require equality to zero only of one of the three determinants (to derive F2h 0). The equality to zero of two remaining determinants will be in agreement with F2h 0 as well"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000619_1.2832484-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000619_1.2832484-Figure2-1.png",
+ "caption": "Fig. 2 The coordinate system and the sign convention of the journal forces",
+ "texts": [
+ " For a given journal speed, the pressure p and the bearing lubricant film thickness h are functions of the journal position and the rate of change of position. The pressure and the film thickness can be expanded in Taylor's series to the first order as follows: P = Po + Px^x + pAx + PyAy -t- p^y ( l a ) h ~ ho + h^x + hAx + hyAy + h^y ( lb) where the subscript \" 0 \" denotes the equilibrium position, ( );i represents a partial derivative with respect to the x perturbation, ( )i is a partial derivative with respect to the x perturbation, and similarly for y and y. With the coordinate system shown in Fig. 2, the bearing stiffness and damping coefficients are obtained in terms of the pressure perturbations as (Peng and Carpino, 1993): Contributed by the Tribology Division for publication in the JOURNAL OF TRIBOUOGY. Manuscript received by the Tribology Division February 29, 1996; revised manuscript received May 17, 1996, Associate Technical Editor: D. E. Brewe. Kyx ^j'j'J J-LnJoi \\_Px cos 9 Py cos 9 sin 6 Py sin 6 Rd9dz (2a) Journal of Tribology JANUARY 1997, Vol. 1 1 9 / 8 5 Copyright \u00a9 1997 by ASME Downloaded From: http://tribology"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003341_bf01213545-Figure8-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003341_bf01213545-Figure8-1.png",
+ "caption": "Fig. 8. Variation of T with 7~3 for different values of",
+ "texts": [
+ " C is found to be quite high for viscous fluid compared with couple stress fluid of the same viscosity for a given value of ~1. C decreases for increasing values of B. Figure 7, contains the graphs showing the variation of C with A for fixed value of #1 --~ 7.65 \u2022 10 _5 and B = 0.5 for different values of u C decreases for increase in Y values, which indicates the suitability of couple stress fluid as efficient lubricant. Porous slider bearing with couple stress fluid 109 110 N. M. Bujurke, H. P. Patil, and S. G. Bh~vi Porous slider bearing with couple stress fluid 111 In Fig. 8, the variation of squeeze film time is shown for different values of couple stress fluid parameters. The squeezing t ime of the step bearing with couple stress fluid is longer t han tha t with a Newtonian fluid. This is a very desirable finding since longer squeeze film t ime results in a smaller co-efficient of friction and almost negligible rate of wear of the bearing. From Fig. 9, it is observed that approaching t ime increases when the porosity of the 112 N.M. Bujurke, H. P. Patti, and S. G"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001929_952470-Figure4-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001929_952470-Figure4-1.png",
+ "caption": "Fig. 4 (a) Rin holder; (b) ring guide; (c) load cell 9 normal oad measurement.",
+ "texts": [
+ " The speed range for this configuration was from 100 to 600 rpm. The pulley system could be reconfigurated in future experiments to a 1: 1 speed ratio for a range of 900 to 3600 rpm. The head of the engine was removed so that a reciprocating fixture could be mounted on the top of the piston. This fixture is guided by two linear bearings to minimize any lateral motion. The assembled recip~ocating fixture and ring holder fixture are shown in Fig. 2. The pieces of the ring holder fixture are shown in Fig. 3. The ring was mounted on a ring holder (Fig. 4a) which was allowed to slide in a ring guide (Fig. 4b) so that the ring was constrained laterally by the liner segment in front and the front surface of the ring guide at the back. A load cell was mounted at the interface between the ring holder and the ring guide (Fig. 4c) so that the normal force on the ring could be measured. The ring guide was connected to the reciprocating fixture by a pneumatically driven air cylinder so that the normal force exerted on the ring could be varied by varying the driving pressure. The rin,g radius could be adjusted to conform to the liner radius of Fig. Redprocator with dng (Only one of ll curvature by two set screws each of which was located at the side of the ring holder (Fig. 4a). two linear bearings is shown.) The liner segment was supported by a floatin,g holder mounted on a pair of linear bearings. The holder was connected by a load cell to the side plate which was fixed to the block of the Kohler engine. The load ceU wiis set up to measure the force component in the direction of the ring travel. At -mid stroke, two LIF probes were installed. The center of the probe volumes were at 81' crank angle from the TDC position. The fiber optics probes were ~nounted on the side plate and light was focused through the windows on the liner to the lubricating oil film ((Fig",
+ "12, in which the LIF signal (uncalibrated) and the normal and frictional forces are shown over 10 cycles. The cycle-to-cycle repeatability is better than 10%. The run-torun repeatability is of the same order. Normal Force Measurements An example of the normal force exerted by the air cylinder on the ring as measured by the load cell is shown in Fig.13a. The force was very repeatable from cycle to cycle but it was not uniform over a cycle. There was a consistent difference between the upstroke and the downstroke value. This non-uniform reading was traced back to the load cell arrangement (Fig. 4c): the load was only measured at the load cell \"button\" which was about 9 mm2 in area. There could be secondary contact points between the ring holder guide, which was driven by the air cylinder, and the ring holder. The variation in force reading could be due to the redistribution of forces at the contact points. The variation was especially pronounce at light loading and high rpm. Frictional Force Measurements A typical friction force measurement is shown in Fig. 13b. The signal was noisy and had been averaged over 10 cycles of data"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003845_3.9671-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003845_3.9671-Figure1-1.png",
+ "caption": "Fig. 1 Rod and tip weight before deformation.",
+ "texts": [
+ " 2) The matrices [M2]0, [ K 2 ] 0 , [ JT4]0, [K5]0, and [M2]0 are assembled as described in the text between Eqs. (20) and (24). 3) The matrices [KQ] and [M0] are assembled according to Eqs. (27). 4) The eigenvalue problem [Eq. (26)] is solved and the frequencies and mode shapes are obtained. Results and Discussion To check the accuracy of the model derived above, the theoretical results are compared in this section with existing experimental and other theoretical results.4'5 The case under consideration is shown in Fig. 1. A cantilevered rod is loaded transversely by a tip weight that causes a substantial deformation. Then, the deformed rod is excited in both the flatwise and edgewise directions (z and y, respectively) and the frequencies of the first natural mode in each direction is found. The experiments included changes in the tip weight magnitude and the load angle y (see Fig. 1). Two aluminum rods with identical rectangular cross sections but different lengths have been used. The rod properties are outlined in Table 1. In Ref. 2, the value for El was taken as that which made the theoretically predicted deflection match experiment for one specific load angle. This provided a structural base from which nonlinear effects as influenced by load angle changes could be assessed. It was not possible to determine EI^ directly from the static experiments, so its value was obtained by dividing EI^ by 16, based on a cross-sectional width-tothickness ratio of 4"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000726_s0043-1648(96)07463-7-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000726_s0043-1648(96)07463-7-Figure1-1.png",
+ "caption": "Fig. 1. Schematic diagram of rotary lip seal.",
+ "texts": [
+ " Furthermore, if a successful seal is reverse mounted (inverting the air and liquid sides), then the seal will leak excessively [6]. 7. A relatively new seal is bidirectional. However, if a seal has been run with the shaft rotation in one direction for a long period of time, then the seal will leak when the rotation is reversed. The above observations provide a basis on which a lip seal model can be constructed. Any prospective model should be capable of explaining all these observations. 2. Model Fig. 1 shows a schematic diagram of a typical lip seal, while Fig. 2 shows the region near the sealing zone, assuming Journal: WEA (Wear) Article: 7463 that the meniscus that separates the sealed liquid from the atmosphere is on the air side of the seal. The pressure P l on the liquid side of themeniscus is below atmospheric pressure, as a result of the action of surface tension forces, while the sealed pressure P s is assumed to be above atmospheric pressure. The flow field within the sealing zone can be thought of as the superposition of two flows",
+ " b axial width of seal E Young\u2019s modulus F cavitation index h film thickness h 0 average film thickness h 1 half-height of asperities h m film thickness at meniscus location hU dimensionless film thickness, h/h 1 hU 0 dimensionless average film thickness, h 0 /h 1 hU 1 dimensionless half-height of asperities, h 1 /b hU m dimensionless film thickness at meniscus location, h m /h 1 I 1 influence coefficient for normal (radial) deformation I 2 influence coefficient for shear (circumferential) deformation I m distance from air-side edge of sealing zone to meniscus, averaged over one wavelength in x direction, when meniscus is on air side of seal l U m dimensionless distance from air-side edge of sealing zone to meniscus, l m /h 1 N number of asperities across axial width of sealing zone P pressure P a ambient pressure P avg pressure averaged over one wavelength in x direction Journal: WEA (Wear) Article: 7463 P c cavitation pressure P contact contact pressure P s sealed pressure P l pressure on liquid side of meniscus PU dimensionless pressure for fluid mechanics analysis, (PyP c )/(mV/h 1 ) PUU dimensionless pressure for deformation analysis, P/E Q leakage rate per wavelength QU dimensionless leakage rate, Q/(lh E/m)2 1 R lip radius R m radius of curvature of meniscus RU dimensionless lip radius, R/b V surface speed of shaft V U dimensionless surface speed of shaft, mV/bE x circumferential coordinate xU dimensionless circumferential coordinate, x/l y axial coordinate y m axial location of meniscus, within sealing zone yU dimensionless axial coordinate, y/b Greek letters g U 6l/h 1 DyU distance between nodes in yU direction d circumferential displacement of lip surface dU dimensionless circumferential displacement of lip surface, d/l u lip angle (see Fig. 1) l wavelength of micro-geometry in x direction lU dimensionless wavelength, l/b m viscosity r density r liq density of the sealed liquid rU dimensionless density, r/r liq s surface tension sU dimensionless surface tension, s/h 1 E t shear stress tU dimensionless shear stress, t/E f dimensionless pressure in the liquid region, related to the dimensionless density in the cavitation region ( ) avg averaged over one wavelength in xU direction ( )i evaluated at ith node [1] R.F. Salant, Elastohydrodynamic model of the rotary lip seal, ASME J"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0002263_6.2003-5349-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0002263_6.2003-5349-Figure1-1.png",
+ "caption": "Fig. 1 Vario X-Treme helicopter",
+ "texts": [
+ " The second section presents the trimming results obtained for the Vario X-Treme model-scale helicopter followed by a stability analysis of the stabilizing bar impact on the helicopter dynamics. The third section focuses on the design and implementation of a forward flight control system for the Vario X-Treme helicopter, and presents the simulation results obtained with the full nonlinear dynamic model. The last section summarizes the contents of the paper and points out directions for future work. This section presents the dynamic model of a single main rotor and tail rotor helicopter equipped with a Bell-Hiller stabilizing bar, as the one depicted in Fig. 1. A comprehensive study of the helicopter dynamic model can be found in 3. For in depth coverage of helicopter flight dynamics, the reader is referred to Johnson7 and Padfield11. The dynamics of the helicopter can be described using a 6 DoF rigid body model driven by forces and moments that explicitly include the effects of the main rotor, Bell-Hiller stabilizing bar, tail rotor, fuselage, horizontal tailplane, and vertical fin. To derive the equations of motion, the following notation is required: {U} - universal coordinate frame; {CM} - body-fixed coordinate frame, with origin at the vehicle\u2019s centre of mass; p = [ x y z ]T - position of the vehicle\u2019s center of mass, expressed in {U}; \u03bb = [ \u03c6 \u03b8 \u03c8 ]T - Z-Y-X Euler angles that parametrize locally the orientation of the vehicle relative to {U}; v = [ u v w ]T - body-fixed linear velocity vector; \u03c9 = [ p q r ]T - body-fixed angular velocity vector"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003284_978-1-4899-7285-9-Figure1.18-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003284_978-1-4899-7285-9-Figure1.18-1.png",
+ "caption": "Figure 1.18. Comparison of the hodograph motion and the particle motion.",
+ "texts": [
+ " The velocity vector is tangent to the path traced by the position vector, and the acceleration is directed in the osculating plane toward the concave side of the path. In this section, we introduce a simpler kind of geometrical description for the velocity and acceleration that uses the velocity vector as the path writer. Imagine a fictitious particle PH whose \"position vector\" xH relative to an origin 0' is equal to the velocity vector of the particle P in the actual motion; and let us write v H = xH for the \"velocity\" of PH\u00b7 Then VH=a. (1.116a) (1.116b) The \"motion\" xH is called the hodograph motion; and the path !l'H traced by xH=v, as shown in Fig. 1.18b, is called the hodograph. In these terms, (1.116) Kinematics of a Particle 47 shows that the \"velocity\" v H in the hodograph motion, called the hodograph velocity, is equal to the acceleration in the actual motion. Hence, the acceleration in the particle motion always is tangent to the hodograph. This is to be compared with the intrinsic description of the actual motion in Fig. 1.18a. Some examples follow. Example 1.17. The velocity vector in a uniform motion of a particle is a constant vector v = v0 \u2022 Therefore, the hodograph is a point xH = v0 , constant. Notice from ( 1.116b) that the hodograph velocity is zero: v H =a = 0. D Example 1.18. If a particle has constant acceleration a # 0, the hodograph is a path described with constant velocity v H =a. The equation of the hodograph is obtained by integrating a= XH; We get XH = V =at+ C, where c is a constant vector. Hence, the hodograph is a straight line"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003241_tasc.2004.830317-Figure2-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003241_tasc.2004.830317-Figure2-1.png",
+ "caption": "Fig. 2. Squirrel cage rotor of the induction motor. (a) Conventional motor (b) HTS motor 1, 5: rotor core 2,6: short ring 3, 7: bar 4, 8: assembled rotor.",
+ "texts": [
+ " If it is too small, it will not recover from quench after starting. Two HTS tapes which were connected in parallel were used for one bar. Critical current of one HTS tape was 115 A at self field. To accommodate the flat HTS tape, shape of the slot of the HTS rotor should be different from that of the conventional motor. Cross section of the HTS rotor is given in Fig. 1. Figs. 1(a) and (b) show the cross section of straight part and the end part, respectively. Outer diameter and inner diameter of the HTS rotor were 78 mm and 22 mm, respectively. Fig. 2 shows the cage rotor of the conventional and the HTS motor. HTS tapes for the short bars are soldered to the HTS tapes for the short rings. Electrodynamometer was coupled to the motor to apply the load. Fig. 3 shows the test system, where the HTS motor, the electrodynamometer and the cryostat are shown. Electro-dynamometer was placed on the top flange of the cryostat. To simplify the cooling system of the HTS motor, whole motor including stator and rotor was put in the cryostat and immersed in liquid nitrogen"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003646_robot.2006.1642337-Figure5-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003646_robot.2006.1642337-Figure5-1.png",
+ "caption": "Fig. 5. Pan tilt unit has 2 D.O.F. and the depth as a virtual D.O.F.",
+ "texts": [
+ " \u00b7 \u201e j\u22121Q i=1 MiLj j\u22121Q i=1 fMj\u2212i \u00ab\u2013 dqj (39) Since j\u22121\u220f i=1 Mi n\u220f i=j Mi = n\u220f i=1 Mi we have dx\u2032 p = n\u2211 j=1 [( n\u220f i=1 Mixp n\u220f i=1 M\u0303n\u2212i+1 ) \u00b7 ( j\u22121\u220f i=1 MiLj j\u22121\u220f i=1 M\u0303j\u2212i )] dqj (40) Recall the equation (30) of the direct kinematics, since in (40) appears again x\u2032 p, we can replace (30) in (40) to get dx\u2032 p = n\u2211 j=1 [ x\u2032 p \u00b7 ( j\u22121\u220f i=1 MiLj j\u22121\u220f i=1 M\u0303j\u2212i )] dqj (41) If we define L\u2032 as function of L as follows L\u2032 j = j\u22121\u220f i=1 MiLj j\u22121\u220f i=1 M\u0303j\u2212i, (42) we get a very compact expression of differential kinematics. dx\u2032 p = n\u2211 j=1 [ x\u2032 p \u00b7 L\u2032 j ] dqj , (43) in this way we can finally write: x\u0307\u2032 p = ( x\u2032 p \u00b7 L\u2032 1 \u00b7 \u00b7 \u00b7 x\u2032 p \u00b7 L \u2032 n )\u239b\u239c\u239d q\u03071 ... q\u0307n \u239e \u239f\u23a0 (44) VI. KINEMATIC CONTROL FOR A PAN-TILT UNIT. We will show an example using our new formulation of the Jacobian. This is the control of a pan-tilt unit. A. The Pan-Tilt unit We implement algorithm for the velocity control of a pantilt unit (PTU Fig. 5) assuming three degree of freedom. We consider the stereo depth as one virtual D.O.F. thus the PTU has a similar kinematic behavior as a robot with three D.O.F. In order to carry out a velocity control, we need first to compute the direct kinematics, this is very easy to do, as we know the axis lines: L1 = \u2212e31 (45) L2 = e12 + d1e1e\u221e (46) L3 = e1e\u221e (47) Since Mi = e\u2212 1 2 qiLi and M\u0303i = e 1 2 qiLi , we can compute the position of end effector using (30) as: xp(q) = x\u2032 p = M1M2M3xpM\u03033M\u03032M\u03031, (48) The estate variable representation of the system is as follows\u23a7\u23aa\u23aa\u23a8 \u23aa\u23aa\u23a9 x\u0307\u2032 p = x\u2032 \u00b7 ( L\u2032 1 L\u2032 2 L\u2032 3 )\u239b\u239du1 u2 u3 \u239e \u23a0 y = x\u2032 p (49) where the position of end effector at home position xp is the conformal mapping of xpe = d3e1 + (d1 + d2)e2 (see eq"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0003271_eurcon.2005.1629898-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0003271_eurcon.2005.1629898-Figure1-1.png",
+ "caption": "Fig. 1. a: A PUMA 560 on a mobile platform. b: Two PUMA 560s on the ground.",
+ "texts": [
+ " These cases were tested on the Itree and the original SBL-PRM algorithms for comparison. The manipulator model used was the PUMA 560 with six degrees of freedom. Figures la and lb are referring to case 1 (ci) and case 4 (c4) respectively. Case 2 (c2) is a PUMA 560 on the ground and case 3 (c3) is two PUMA 560 each of of them mounted on a mobile platform. The object model in the simulation is a car and the task is to move the manipulator(s) from a start configuration to the goal position (at the other end of the line path) as shown in Figure 1. the s-ants but the paths connected from the food, g, to any of s-ants trail will definitely give the path to the food, s. However, the g-ants will get the shortest path by choosing the appropriate trails with the heuristic provided in the global table. Finally when all g-ants have made the In each of the experiments, the number of configurations was calculated and the running time was recorded. The results in Figure 1 and Figure 2 shown below were obtained on 2.60 GHz Pentium4 processor with 512 MB of main memory running Microsoft Visual C++ 6.0. The parameter p was set to 0.15 and the resolution E to 0.012. A path in configuration space between two configurations is considered collision free if a series of points on the path in every successive point are closer apart than some e. As can be seen in Figure 2, Itree-ACO has shown a smaller number of configurations generated on the robot(s) path than the configurations generated by SBLPRM"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0000606_(sici)1096-9845(199610)25:10<1139::aid-eqe606>3.0.co;2-s-Figure1-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0000606_(sici)1096-9845(199610)25:10<1139::aid-eqe606>3.0.co;2-s-Figure1-1.png",
+ "caption": "Figure 1. Slide rotation of the body with a fixed direction of the friction force",
+ "texts": [
+ " For example, if the ground motion is harmonic with respect to time, ig = uo cos ot (1) then sliding certainly occurs if p < 0.537ag/g (2) where ag = u o o . Thus, we accept the third assumption to be realized: (3) the friction coefficient p is small enough to provide sliding. If the body starts to slide the direction of relative sliding between the body and the ground is fixed for a period of time, when we call 'the first phase' of the motion. For this phase the friction force Ff does not change its direction, and we have (see Figure 1) Fc = ~ L N (3) where N is a normal reaction of the ground. The plane motion of the block is described by the following equations: mx, = Ff my, = N - mg I $ = Fryc - N ( a cos cp - h sin cp) where y , = asin cp + hcos cp. SLIDE ROTATION O F RIGID BODIES 1141 Here (x,y) is the fixed Cartesian co-ordinate system, 2a the width of the block, 2h its height. The point above any variable denotes its derivative with respect to the time t. The moment of inertia m 3 I , = - (a2 + h 2 ) It follows from equations (3)-(5) that N = m ( j c + g) yc = (acoscp - hsincp)$ - (asin cp + hcoscp)qj2 I,$ = m ( j c + 9) [ p ( a sin cp + h cos cp) - (a cos cp - h sin cp)] Taking into account equalities (6) and (7b) the last equation can be rewritten as follows: al(cp)$ + bl((P)q2 = C l ( c p ) where al(cp)= 1 +a2-3(coscp-asincp)[(p+u)sincp+(pa-1)coscp] bl (cp) = 3(sin cp + u cos cp) [( p + u) sin cp + ( p a - 1) cos cp] 9 cl(cp) = 3 - [(p + u) sin cp + ( p a - 1) cos cp] U The main geometric parameter h a = - U is a relative height of the construction"
+ ],
+ "surrounding_texts": []
+ },
+ {
+ "image_filename": "designv11_6_0001419_robot.1991.131938-Figure7-1.png",
+ "original_path": "designv11-6/openalex_figure/designv11_6_0001419_robot.1991.131938-Figure7-1.png",
+ "caption": "Fig. 7: Unstable Area of Circling Gaits Based on the First Method with p = 314.",
+ "texts": [
+ " Since At2 is greater than x , the gait stability margin of the +a: type wave-circling gait is less than zero. Similarly, we can prove that +y type, -y type and -y type wave-circling gaits have a negative stability margin when the turning center is coincident with the gravity center. Therefore, for a given angle T, there should exist a critical turning radius R, so that the gait is st.able when R 2 R,. By calculat,ing the R, for many y, we can construct an unstable area of turning center for the wave-circling gaits. The unstable area of the wave-circling gait of t h e walk- ing chair is shown in Fig. 7 by using the first strategy. The unstable area is symmetrical about the body longitudinal and lateral axes due to the symmetrical leg workspaces. Fig. 8 shows the unstable area of the wave-circling gaits with the second strategy. Compared to first strategy, the unstable area is greatly reduced. Thus, the second strategy is more effective and we will apply the second strategy in the following examples. Fig. 9.a shows the relationship between S,,, and a in the following range 0\u2019 5 cy 5 360\u2019. The duty factor /3 is equal to 5/6 and turning radius R is a constant"
+ ],
+ "surrounding_texts": []
+ }
+]
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