diff --git "a/designv7-3.json" "b/designv7-3.json" new file mode 100644--- /dev/null +++ "b/designv7-3.json" @@ -0,0 +1,23119 @@ +[ + { + "image_filename": "designv7_3_0002867_9312710_09367135.pdf-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002867_9312710_09367135.pdf-Figure8-1.png", + "caption": "FIGURE 8. Pre-grasping EE configuration setpoints. P and r are calculated based on the stand markers detection, whereas d1, d2, and \u03b1 are user-defined.", + "texts": [ + " In our experiments, the pipe lies on a pair of v-shaped hangers mounted on aluminum stands, with ArUco markers placed below the hangers to estimate the holding points (H1,H2). The pipe centerP is considered equidistant to both holding points, and the direction r is aligned with \u2212\u2212\u2212\u2192 H1H2 . A predefined distance d1 is then used to approximate the grasping points (P1,P2): P = 1 2 (H2 \u2212H1) r = (H2 \u2212H1) |H2 \u2212H1 | P1 = P \u2212 r \u00b7 d1 P2 = P + r \u00b7 d1 (36) The pre-grasping EEs configuration (\u03b7ee1,\u03b7ee2) is predefined in the robot\u2019s manipulation parameters, where d2 is the pre-grasping distance and \u03b1 the orientation angle (see Fig. 8). This configuration is defined with respect to the detected pipe position P and orientation vector r in the N \u2212 frame. Let the orientation of the pipe in the N \u2212 frame be represented by a 3 \u00d7 3 matrix Rp = [rp1 rp2 rp3 ] where rp1 = (-r )\u00d7[0 0 1]T , rp2 = -r and rp3 = rp1\u00d7rp2 . Then the desired grasping orientation can be computed by simply rotating the Rp frame through an angle of \u03b1 around the y axis: Rd = Ry(\u03b1) \u00b7Rp = [rd1 rd2 rd3 ] T (37) Finally, each pre-grasping pose is given by: \u03b71ee1 = P1 \u2212 d2rd3 \u03b71ee2 = RPY2Euler(Rd ) \u03b72ee1 = P2 \u2212 d2rd3 \u03b72ee2 = RPY2Euler(Rd ) (38) 37676 VOLUME 9, 2021 where the function RPY2Euler(\u00b7) computes the Euler angles of the input rotation matrix" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004941_07-14_b1_zhu2008.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004941_07-14_b1_zhu2008.pdf-Figure2-1.png", + "caption": "Fig. 2. Three FSPMs for spine-motion simulator", + "texts": [ + " Type synthesis of 3R2T FSPM had been a difficulty (Merlet, 2000) and hot topic until dozens of them are proposed (Jin et al., 2001; Fang & Tsai, 2002; Huang & Li, 2002; Kong & Gosselin, 2002; Giuseppe, Lim et al., 2003; Li et al., 2004). Comparing with the degree of concern for them in type synthesis, their application seems to be an inactive area. Among near twenty theoretical types of 3R2T FSPMs currently, there are only three manipulators without passive prismatic and cylindrical pairs, including 5-RRR(RR), 5- (RRR)RR, 5-(RRR)(RR) as shown in Fig.2, where \u201cAB\u201d denotes axes of pairs A and B are parallel, \u201c(AB)\u201d denotes axes of pairs A and B intersect at a common point. www.intechopen.com Parallel Manipulators, Towards New Applications 500 For a 5-RRR(RR) parallel manipulator shown in Fig. 3, the movable and base platforms are connected by five identical limbs each with five revolute joints. Axes of three joints adjacent to the base platform are perpendicular to the base; the other two intersect at point O2. The line passing through the origin O1 and O2 is perpendicular to the base platform" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004536_lator-Oloworaran.pdf-Figure29-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004536_lator-Oloworaran.pdf-Figure29-1.png", + "caption": "Figure 29: Simulated robot joint differences", + "texts": [], + "surrounding_texts": [ + "The GUI provides an intuitive interface for the user to interact with the simulated robot. As the system was aimed towards users without robotic experience, the GUI has been styled simply with a minimal number of sliders and buttons which perform high level functions. These control the functionality to load robots, restart the scene, quit the scene, and invoke inverse kinematics. When the user first loads the program, they will see the following base screen: This contains three buttons for different user functions. The quit button will exit the system, while the restart button will delete any previously loaded objects and display Figure 23 to the user once again. The send command feature is used for sending commands to the real robot through a serial port, as well as controlling the robot\u2019s virtual counterpart. Refer to section 4.3 for more details. Pressing the load button will open a file selection window. The user will use this to select their robot configuration text file. Once a valid robot file is selected and loaded, added controls will be presented to the user in the form of sliders for controlling the robot DH parameters and an inverse kinematics button. Outside of the GUI, camera navigation with arrow keys is also provided for changing view of the scene. 4.1.5 Inverse Kinematics IK is implemented using the method described in section 2.12, though it has been adapted in multiple ways to suit this system. Firstly, it has been generalised to any number of joints and also includes calculations for the link twist angle, in addition to the hinge angle as originally defined. Because of this, IK can be performed in three dimensions rather than two (changing hinge angle would only rotate joints in around the X-Y plane). Currently, the IK algorithm tries to direct the arm to a pre-loaded cube in the scene within the executable system. But this target can be edited within the Unity editor to see IK for any target position in the scene. 4.2 Specification of Robots Robots will be specified through use of a structured text file. This file will contain 20 sets of inputs including information on how the robot is built, system path to robot .obj file models, its initial DH parameters and frames of reference, and many other parameters about the robot. To view the structure of the document, see Appendix C. 4.3 Real Robot 4.3.1 Construction The real robot was constructed with intent of having it simulated in the system and compared to for data collection. From here on, the original online design this robot was adapted from will be referred to as the online specification. The only special tool needed for construction was a 3D printer for fabricating all the online model files and a soldering iron for the circuitry. Otherwise all other tools used were commonplace. While the physical design is completely the same as the online specification, the electrical parts were slightly changed which lead to the wiring being reworked. The online specification\u2019s program was not used in favour of a custom one that more accurately represented basic robot control. For full construction images (including final set up) see Appendix D. 4.3.2 Specifications The chosen robot has three DOF, the first joint allows the robot to rotate its base about the Y-axis. The next two joints allow the robot to rotate its arm about the Z-axis. Finally, a two-pronged gripper exists at the end of the last robot limb. Note here, while the point which connects the gripper to the rest of the robot is technically a hinge joint, the gripper hinge is controlled completely mechanically to force it to stay horizontal. Hence, the joint is considered as essentially constrained and not a DOF. (Refer to Appendix E for details on robot notation) The robot will have a total horizontal reach of 38.2cm and total vertical reach of 36cm. See Appendix F. for robot dimensions. All three robot joints will be controlled from their own stepper motor, while a servo will be incorporated in order to control the gripper fingers. The stepper motors each drive gears that are connected to the robot and this allows them to turn the robot. The servo works similarly, with a gear attached to the servo and to the gripper fingers, as the servo rotates so too do the prongs which can open or close the gripper. The three stepper motors will have their own motor controller modules, and these will be controlled by an Arduino Nano. For a full parts list, refer to Appendix G. 4.3.3 Electrical Wiring and Programming The system was powered by a 12V DC adapter, as well as through the use of a DC/DC buck converter to gain a 5V supply. The stepper motors needed to operate on the 12V supply as they draw high amounts of power and current. In comparison, the Arduino and servo both operate off 5V inputs. In order to accurately control the stepper motors, L298N modules were incorporated which took input signals from the Arduino and turned the stepper motor accordingly. All components are either soldered together or use female to male wire plugs. To see the full electrical diagram, please see Appendix H. The robot was programmed as to constantly read data coming in off a computers serial port which was directly connected to the Arduino through a USB 2.0 cable A-B. Commands it receives must be of the structure: \u201cL\u201d [joint number] [rotation amount] Or \u201cS\u201d [0 or 1] The first command will rotate a robot joint by a certain amount of degrees (by rotating the stepper motor by a certain number of steps). The second command sends a signal to the servo which either turns the servo counter-clockwise for 1 (which closes the gripper) or clockwise for 0 (which opens the gripper). Any other commands are ignored. The program also keeps track of the current robot angle by recording changes made through commands, though this assumes the robot started from a set position and only moves due to the commands. 4.3.4 Final Product and Virtual Model By using the models provided in the online specification and using Blender to convert them from .stl files to .obj files, the system was able to recreate the physical arm in a virtual environment. While the two systems appear visually similar there is one main difference. The simulated robot is unable to model the stepper and servo rotations, so they have been omitted. Due to this the gripper in the simulated robot appears to be floating when it should really be together with the servo. The gripper moves closer and further apart but does not rotate open and closed as the physical robot does. To ensure a realistic representation, virtual robot has been configured to move with the same DOF as the physical robot. 5 Results 5.1 Scale Firstly, to ensure our simulation will be useful, the accuracy of the scaling for this robot is shown. The specified lengths of our robot are known from measurements of the 3D models in Blender (see Appendix F) but they have been scaled down to make them more manageable for Unity. Of importance, here, are the lengths of the height from the ground to the first joint, the link length from the first joint to the second and finally the link length from the second joint to the gripper. In Unity these distances between each joint are checked to get our scale factors (actual length divided by simulated). This result is not completely unexpected, while the two links have a very close scale factor, the base is slightly higher. The base was constructed in Blender by joining three individual models together so it is likely small errors could have occurred in the process. In light of this, the average of the nonground \u2013 joint 1 measurements, 2.575, shall be taken as the scale factor from the virtual robot to reality and it is assumed the simulated height from ground to joint 0 is actually 2.97x2.575 = 7.65cm. 5.2 Single Joint Movements For this test, The final end effector positions are compared after one movement for a single joint, performed over every joint. Measurements of position will be taken from the middle of the joint which connects the last robot link to the gripper. For reference, the measurement will be relative to the middle of the base of the robot and presented in X-Y-Z coordinates. The test was performed in respect to each axis and for each joint (where joint 0 is the base twisting, joint 1 is the first robot hinge joint and joint 2 is the second) and the resulting error in virtual robot end-effector position, compared to the physical robot, is portrayed below. Note for the Y-axis with joint 0 and Z-axis for joints 1 and 2, the end effector did not move in that axis due to those joints rotation types, hence the near constant error values. Due to the mechanical constraints of the robot, some joints have more results and reachable angles than others. For raw error value graphs and tabulated data, see Appendix I and K. The maximum and average errors for each test are presented below. 5.3 Repeatability To test for repeatability, the simulated robot was put through increasingly long chains of commands (up to 5), recording the end-effector position and orientation, then put through the same commands in reverse order and again recording the end-effectors, position and orientation (i.e. the test first involves doing one movement and then returning to the start, then two movements and returning to the start etc.). This test also includes some (manually forced) self-collisions to ensure no parts are dislodged and the robot configuration is altered, after these the robot was set back to the same angle and the test continued. The 5 movements were: \u2022 Rotate Joint 0 by +20 \u2022 Rotate joint 1 by +100 \u2022 Rotate joint 2 by -100 \u2022 Rotate joint 0 by -50 \u2022 Rotate joint 1 by -50 Number of movements completed vs error in end-effector position at start and destination 5.4 Inverse Kinematics Test To run the IK test, two types of robots where considered, the physical robot model which has 3- degrees of freedom and 2 links and a 3-link 8-DOF robot with very simple architecture. Each robot was given 10 random positions to move towards and would generally start from the position the last run of IK ended in (if it was not too disadvantageous). The IK was considered successful if any part of the gripper was touching the target location, or if the target was out of reach, the robot must be pointing towards it with close to its maximum extent. 5.5 Analysis of Results From these tests, the accuracy of the system can be determined. Both the scale test and single movement tests show the ability of the robot to mimic a real robotic arm. While the scale test shows the ability of the simulation to accurately configure a robot, the movement test displays the system\u2019s ability to accurately manipulate the robot. The scale test gave good results, with the robot being able to be configured to a (nearly) consistent scale. The movement test exposed certain angles which were much more inaccurate than others, with joint 2 being highly inaccurate at most points. Otherwise, joints 0 and 1 had relatively small average errors. The repeatability test shows the system is completely repeatable, meaning the errors from the movement test are not accumulated or random. In this test, collisions encountered (once adjusted back to the pre-collision angle) had no impact on the final position of the end-effector. It is important to note the real robot was likely not the most accurate itself, the stepper motor accuracy was 200 steps/revolution. This means for a 360o there are only 200 steps, giving an error of \u00b10.9o. Depending on the pose of the robot this can have noteworthy influence on the end-effector position in a certain axis. It may also be that this robot, who has many mechanical limits, is not suitable to be modelled in a simulation which cannot model them. Considering these factors, the system is still able to simulate robot movement well enough for our purpose, to allow new users to easily manipulate an articulate robot using real robot theory. It is not designed to compete with much larger and more accurate simulations. One conclusion that can be drawn from the (albeit limited) IK test is that the more complex the robot, configuration-wise, the worse the Jacobian Transpose method will work. The 2-link physical had a much smaller chance of colliding with itself (causing the robot to be unable to progress), both due to its lower number of links and its lower DOF. The 3-link robot could easily tie itself into a knot while trying to reach a certain position. This resulted in two collision loop failures for the 2-link robot, compared to six for the 3-link robot. In general, the 2-link robot performed better, achieving its goal (or pointing towards unreachable ones) in five of the tests. The 3-Link robot performed more poorly, only achieving its goal twice in ten tests. See appendix J for more information on tests and result categories. 5.6 Limitations As the system allows for such a wide degree of customisation, there is no guarantee that these tests will hold generally true for all robots. The system aims to expose and allow users to interact with the functionality of an articulate robot but does not compare to much larger systems which focus on accuracy. This is a form of simplification for the system but also a downside. Robots can be created and configured easily without many parameters outside of how they can move and how the parts are positioned, but they lack accurate functionality such as that of simulating motor control, sensors or rigorous IK methods. The system is not suited for any formal robot development, the amount of error is too high for a robot whose main benefits include being more accurate than humans. As such, only informal small robots should be modelled with this system. If one wanted to quickly see the DH parameters, they needed to create a robot and visualise how they would work this system would be. To allow for collision detection, the Unity physics engine is used but this also applies unwanted forces on the robot. The system is not designed to have the robot be hit or put into physically impossible poses, in such situations the physics engine has to deal with improper interactions causes the system to lag until it is unusable." + ] + }, + { + "image_filename": "designv7_3_0004580_73917_FULLTEXT01.pdf-Figure2.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004580_73917_FULLTEXT01.pdf-Figure2.4-1.png", + "caption": "Figure 2.4. Torque-Current curve for a DC motor [9]", + "texts": [ + " Because of all these factors electric grippers are getting more common in the industry and are thought to become even more frequently occurring in the future. When using a DC motor the proportionality between the current and torque can be used to change the force a gripper is exerting on an object. This relationship is given by equation 2.1 T = I \u00b7 kT (2.1) where T is the output torque of the DC motor, I is the current through the motor and kT is the torque constant which is specific to the motor. This equation can be represented by a linear curve where the torque constant is the slope of this curve, shown in Figure 2.4 7 CHAPTER 2. THEORY With the output torque the force applied by the gripper can be calculated using the diameter, dg, of the gear which converts the rotational movement into a linear motion, according to equation 2.2 [9] T = F \u00b7 dg (2.2) To find the relationship between the current and the exerted force, tests can be done using a force senor in the gripper to measure this force at different current inputs. By adding the results into a graph and using a curve fitting method an expression for the relationship between the current and the force can be found" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003285_f_version_1691568217-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003285_f_version_1691568217-Figure2-1.png", + "caption": "Figure 2. Reconfiguration mechanism for the delta robot.", + "texts": [ + ", the distance between the origin of the robot\u2019s frame and point Ai), r is the radius of the moving platform, (i.e., the distance between the center of the platform and point Ci), \u03b1i is the angle between axis X of the fixed frame and each of the three kinematic chains that make up the robot, measured about the fixed Z axis; L1 and L2 are the length of the first and second links of the kinematic chains, respectively, and P is the 3D end-effector position expressed in the fixed frame. With the reconfiguration capability considered in this work, R becomes a (joint) variable. In Figure 2, the reconfiguration mechanism for the robot is shown. More details on the reconfiguration analysis and mechanism can be found in [16]. The following key points can be defined with respect to the robot\u2019s fixed reference frame: Ai = R cos(\u03b1i) R sin(\u03b1i) 0 (1) Bi = (R + L1 cos(\u03b8i1)) cos(\u03b1i) (R + L1 cos(\u03b8i1)) sin(\u03b1i) \u2212L1 sin(\u03b8i1) (2) Ci = Px + r cos(\u03b1i) Py + r sin(\u03b1i) Pz (3) P = Px Py Pz (4) Based on the work reported in [16], and considering the reconfiguration, we define the active joints and Cartesian coordinate vectors of the end-effector as q = R \u03b811 \u03b821 \u03b831 (5) and x = P = Px Py Pz (6) respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.30-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.30-1.png", + "caption": "Figure 5.30: Concept 1:2 with a larger configuration modeled in Autodesk Inventor", + "texts": [ + " The difference with this compared to exiting ideas is reduce the number of parts required to construct a frame. Two housings are fused together in a C-shape. Two \"extensions\" are also fused into a C-shape. The housing is cut all the way through which allows the shapes to slide in and out of one another. In doing this, the adaptability of the assembly is lowered, but the integrity and robustness is vastly increased. Stoppers can be utilized were the extension exits the housing to tighten the frame further The following two images, figure 5.29 and figure 5.30 respectively, shows the frame in its smallest base form and with two additional pieces added per side. This was done to showcase the feature of increasing its size based on the number of wanted rubber modules. The frame is made up of three different parts in total. Two different L-profile beams are attached with an L-shaped connector. One of the main issues that was brought up during the workshop was the issue of tightening and leak proofing flat metal surfaces in contact. The first concept uses the idea of having different dimensions for the frames mounting holes and corner fasteners, to squeeze the frame walls together" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000393_download_13581_13430-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000393_download_13581_13430-Figure1-1.png", + "caption": "Figure 1: RLW robot welding a car front door.", + "texts": [ + " The robot arm moves the scanner with a maximum speed of 0.2-0.5 m/s, and due to the low scanner weight, with a rather high accel- eration. The scanner contains a laser source, two mirrors for the rapid positioning of the laser beam (up to 5 m/s), and a focus lens to regulate the focal length. Hence, the typical RLW robot is a redundant kinematic system with 7 degrees of freedom, in which the mirrors of the scanner move an order of magnitude faster than the mechanical joints of the robot arm. A typical RLW robot is depicted in Figure 1. The robot can weld a seam if the scanner is located within the focus range (e.g., 800-1200 mm) from the seam, and the inclination angle (i.e., the angle between the laser beam and the surface normal) is not more than a specified technological parameter (e.g., 15\u25e6). These constraints define a truncated cone above the seam, which will be called the access volume of the seam. Since the length of a stitch is significantly smaller than other characteristic dimensions in the welding process, it is reasonable to assume that all points of the stitch can be processed from a single, conical access volume" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000262_24_CAD24_131-135.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000262_24_CAD24_131-135.pdf-Figure3-1.png", + "caption": "Fig. 3: Process of base-link registration: (a) OBB of base-link TLS points, (b) OBB of the base-link CAD points, (c) Result of rough registration, (d) Result of sparse ICP registration.", + "texts": [ + " 2(e), the color of each point indicates the distance of the shortest path. The shortest path distances are also calculated using the CAD point cloud of the base link in the same way. Then, TLS points with distances shorter than the maximum of the CAD point cloud are selected as candidate points of the base link, as shown in Fig. 2(f). The CAD point cloud of the base link is fitted to the candidate points of the base link. For rough registration, an oriented bounding box (OBB) is created from each of the CAD point clouds and the TLS candidate points, as shown in Fig. 3(a, b). Then, the OBB of the CAD point cloud is moved and rotated Proceedings of CAD\u201924, Eger, Hungary, July 8-10, 2024, 131-135 \u00a9 2024 U-turn Press LLC, http://www.cad-conference.net at equal intervals so that the sum of the shortest distances between each point in the CAD point cloud to the TLS point cloud is minimized. As shown in Fig. 3(c), the calculated position is used as the rough registration result. Finally, the sparse ICP algorithm [2] is applied for precise registration, as shown in Fig. 3(d). Calculation of Main Links: In our method, the CAD point cloud of each link is fitted to the TLS point clouds sequentially, starting from the base link. Then, the rotation angle of each link is calculated by following child links from the base link. Initially, the rotation angle of each link is determined roughly; then the exact rotation angle is calculated by constrained registration using the relationships between links. To roughly determine the rotation angle at each joint, the CAD point cloud is rotated at equal intervals around the axis defined in the URDF" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003221_f_version_1701332048-Figure18-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003221_f_version_1701332048-Figure18-1.png", + "caption": "Figure 18. Ca era place ent considerations. (Left) Illustration of the decision for the ini u idth of eld f i . (Right) Illustration of the calculation for the i i u orking distance needed to co pletely cover the indo corner area.", + "texts": [ + "31\u00a0 For the wrist camera attached to the robot arm UR5e, its field of view was between 100 mm by 75 mm and 640 mm by 480 mm, and the focus ra ge starte from 70 mm to infinity. Based on the specifications and the height of the window researched in this study, a required minimum field of view (FOV) to fully cover the corner area is around 110 mm by 110 mm; however, considering that the placement angle of the window frame might vary, the narrowest FOV should not be less than 156 mm, which is the maximum length of the seam, as shown in Figure 18. If the shorter width should reach at least around 156 mm, then the working distance from the camera should be around 146 mm above the object. In addition, the height of the window frame (83 mm) should be taken into consideration, as well. Therefore, the proper vertical distance from the camera to the working table should not be less than 229 mm, which equals the height of the window plus the working distance. In order to reserve enough space for the end effector (cleaning tool), a fixed distance was eventually set to 300 mm in the z axis", + "\u00a0 For\u00a0the\u00a0wrist\u00a0camera\u00a0attached\u00a0to\u00a0the\u00a0robot\u00a0arm\u00a0UR5e,\u00a0its\u00a0field\u00a0of\u00a0view\u00a0was\u00a0between\u00a0100\u00a0 mm\u00a0by\u00a075\u00a0mm\u00a0and\u00a0640\u00a0mm\u00a0by\u00a0480\u00a0mm,\u00a0and\u00a0the\u00a0focus\u00a0range\u00a0started\u00a0from\u00a070\u00a0mm\u00a0to\u00a0infinity.\u00a0 Based\u00a0on\u00a0the\u00a0specifications\u00a0and\u00a0the\u00a0height\u00a0of\u00a0the\u00a0window\u00a0researched\u00a0in\u00a0this\u00a0study,\u00a0a\u00a0required\u00a0 minimum\u00a0field\u00a0of\u00a0view\u00a0(FOV)\u00a0to\u00a0fully\u00a0cover\u00a0the\u00a0corner\u00a0area\u00a0is\u00a0around\u00a0110\u00a0mm\u00a0by\u00a0110\u00a0mm;\u00a0 however,\u00a0considering\u00a0that\u00a0the\u00a0placement\u00a0angle\u00a0of\u00a0the\u00a0window\u00a0frame\u00a0might\u00a0vary,\u00a0the\u00a0nar- rowest\u00a0FOV\u00a0should\u00a0not\u00a0be\u00a0less\u00a0than\u00a0156\u00a0mm,\u00a0which\u00a0is\u00a0the\u00a0maximum\u00a0length\u00a0of\u00a0the\u00a0seam,\u00a0as\u00a0 shown\u00a0 in\u00a0Figure\u00a018.\u00a0 If\u00a0 the\u00a0shorter\u00a0width\u00a0should\u00a0reach\u00a0at\u00a0 least\u00a0around\u00a0156\u00a0mm,\u00a0 then\u00a0 the\u00a0 working\u00a0distance\u00a0from\u00a0the\u00a0camera\u00a0should\u00a0be\u00a0around\u00a0146\u00a0mm\u00a0above\u00a0the\u00a0object.\u00a0In\u00a0addition,\u00a0 the\u00a0height\u00a0of\u00a0the\u00a0window\u00a0frame\u00a0(83\u00a0mm)\u00a0should\u00a0be\u00a0taken\u00a0into\u00a0consideration,\u00a0as\u00a0well.\u00a0There- fore,\u00a0the\u00a0proper\u00a0vertical\u00a0distance\u00a0from\u00a0the\u00a0camera\u00a0to\u00a0the\u00a0working\u00a0table\u00a0should\u00a0not\u00a0be\u00a0less\u00a0 than\u00a0229\u00a0mm,\u00a0which\u00a0equals\u00a0the\u00a0height\u00a0of\u00a0the\u00a0window\u00a0plus\u00a0the\u00a0working\u00a0distance.\u00a0In\u00a0order\u00a0to\u00a0 reserve\u00a0enough\u00a0space\u00a0for\u00a0the\u00a0end\u00a0effector\u00a0(cleaning\u00a0tool),\u00a0a\u00a0fixed\u00a0distance\u00a0was\u00a0eventually\u00a0set\u00a0 to\u00a0300\u00a0mm\u00a0in\u00a0the\u00a0z\u00a0axis.\u00a0Since\u00a0the\u00a0camera\u00a0distance\u00a0to\u00a0the\u00a0workstation\u00a0was\u00a0fixed,\u00a0as\u00a0well\u00a0as\u00a0 the\u00a0height\u00a0of\u00a0the\u00a0robotic\u00a0arm\u00a0at\u00a0the\u00a0initial\u00a0position,\u00a0the\u00a0height\u00a0measurements\u00a0(z\u00a0axis)\u00a0were\u00a0 kept\u00a0as\u00a0a\u00a0constant\u00a0true\u00a0value\u00a0and\u00a0not\u00a0estimated\u00a0to\u00a0simplify\u00a0the\u00a0system\u2019s\u00a0operations.\u00a0 Figure\u00a018.\u00a0Camera\u00a0placement\u00a0considerations.\u00a0 (Left)\u00a0 Illustration\u00a0of\u00a0 the\u00a0decision\u00a0 for\u00a0 the\u00a0minimum\u00a0 width\u00a0of\u00a0field\u00a0of\u00a0view.\u00a0 (Right)\u00a0 Illustration\u00a0of\u00a0 the\u00a0calculation\u00a0 for\u00a0 the\u00a0minimum\u00a0working\u00a0distance\u00a0 needed\u00a0to\u00a0completely\u00a0cover\u00a0the\u00a0window\u00a0corner\u00a0area.\u00a0 5.2.\u00a0Framework\u00a0Validation\u00a0 5.2.1.\u00a0Module\u00a01\u00a0 The\u00a0first\u00a0module,\u00a0window\u00a0identification\u00a0and\u00a0location,\u00a0aimed\u00a0to\u00a0locate\u00a0the\u00a0rough\u00a0po- sition\u00a0of\u00a0 the\u00a0start\u00a0point\u00a0 to\u00a0enable\u00a0 the\u00a0robot\u00a0 to\u00a0perform\u00a0an\u00a0 initial\u00a0approach\u00a0 towards\u00a0 the\u00a0 corner\u00a0of\u00a0the\u00a0window\u00a0frame.\u00a0To\u00a0validate\u00a0the\u00a0coordinate\u00a0estimation\u00a0process,\u00a0several\u00a0win- dow\u00a0corners\u00a0were\u00a0placed\u00a0one\u00a0by\u00a0one\u00a0at\u00a0a\u00a0random\u00a0position\u00a0within\u00a0the\u00a0working\u00a0area", + " The actual location was measured as well using a manual tape measure with 1 mm of accuracy to provide the ground truth of the experiment. The results of locating the window corner area are presented in Table 1. Based on the results in Table 1, the performance of the identification algorithm can be statistically analyzed. The average measurement error (mean \u00b1 standard deviation) of the window location is 7.124 \u00b1 2.975 mm and 6.612 \u00b1 3.390 mm for the virtual environment and the real environment, respectively. Given the dimensions of the window corner and required field of view (FOV) shown in Figure 18, the area of the whole window corner was 110 mm by 110 mm, and the FOV of the set height was around 232 mm by 309 mm. The FOV at the set height was at least 86 mm wider than the required FOV to fully cover the corner for both sides. Therefore, a 6 to 7 mm measurement error represents around a 5% error relative to the window corner area and is thus considered acceptable, considering the purpose of the algorithm (approximation step). Buildings 2023, 13, 2990 19 of 24 5.2.2. Module 2 The main function of the second module was to detect the weld seam with the pretrained image segmentation model" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002374__issue-pdf_14110.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002374__issue-pdf_14110.pdf-Figure5-1.png", + "caption": "Figure 5. Robot prototype design with pneumatic actuation for lower limb rehabilitation", + "texts": [], + "surrounding_texts": [ + "The proposed design foresees the programming of the reference movement trajectories by a physiotherapist, in addition to the appropriate limits for the load forces applied to the limbs during the exercises. As seen from Figure 4, the robotic system for rehabilitation of upper and lower limbs is composed of following components: mechanism, pneumatic system and control system. The control system consists of hardware, software, sensors and man-machine interface devices, which allow the implementation of control strategies, operation commands and data acquisition. The mechanism consists of a set of rigid links joined by revolute joints and mounted on a fixed base in the chair, whose function is to perform the desired movements in the rehabilitation exercises. Figures 5 and 6 show the simple design of a pneumatically driven robotic workbench for rehabilitation of upper and lower limbs that it was designed on CAD (Computer Aided Design) software. each mechanism joint is performed by a pneumatic servo positioner comprising a double-acting cylinder and simple rod, and a five-way directional servo valve. Figure 7 presents the representation of the pneumatic scheme of the robot, designed according to ISO 1219 2012). Table 1 describes the basic elements of the pneumatic robot drive system, according to the numerical indication of the Figure 6. For each limb i (upper or lower) to be exercised with an angular movement i of the mechanism, it is necessary to apply a load force fLi provided by the pneumatic system. The mechanical system of the robotic workbench is shown in Figure 4, where the main loads and parameters involved in each limb rotation dynamics are gravity torque fLi, the moment of inertia I0i of the rotating mass (mechanism and limb) around the rotation axis, the angular acceleration of the platform and the distance r from the turning center to the point of application of the force. Applying the sum of the torques (\u2211Toi), we have Equation (1). 22411 Roberta Goergen et al. , 2011; Wolbrecht The actuation of -1 standard (ISO, Tgi, load force ioigiLioi ITfrT In that manner, we have Equation (2), which represents the dynamics of the rotating mechanism coupled with pneumatic actuator. piLigiioi FrfrTI where Mi is the displaced mass in pneumatic actuator, the cylinder piston acceleration, Design of a pneumatically driven robotic workbench for rehabilitation rehabilitation \u2026\u2026\u2026\u2026\u2026..(1) atriii FyM ..\u2026\u2026\u2026\u2026(2) iy is Fpi is the pneumatic force given by Equation (7), and Fatri is the friction force in pneumatic actuator. The kinematic relation between linear movement yi by the pneumatic actuator rod and the angular movement i by the rotating platform can be obtained through the methodology proposed by Valdiero (2012), and is shown in Equation (3): iiiiiiiii LLLLLy 321 2 2 2 1 cos2)( \u2026\u2026..(3) where the constructive parameters L1i, L2i , L3i and i are described in detail in Valdiero (2012). Pneumatic force Fpi is each pneumatic actuator and it is given by Equation (4): biiaiipi pApAF 21 (4) where A1i and A2i are the transversal section areas in the chambers of the pneumatic cylinder i , and pai and pbi are the respective pressures in these chambers, whose values can be measured by means of pressure transducers. The study of pneumatic position servo systems is complex when compared with others position servo drives types, because air is very compressible and the friction force Fatri has a highly non-linear behaviour. Friction is a multifaceted non-linear phenomenon that exhibits many non-linear characteristics. They are composed by well-known and classic static friction (stiction), Coulumb friction, viscous friction and drag friction, that compose the simpler models based in static maps. Otherwise, they are composed by more complex dynamic phenomena known as Stribeck friction, rising static friction, frictional memory and presliding displacement (Valdiero, 2012). It is important to emphasize that, in general the friction characteristics are dependent of velocity, temperature, movement direction, lubrication and the wear between contact surfaces, and even position and movement history. It is possible to determinate easily the static parameters of the friction model through experimental tests carried out with constant velocity. These static parameters can be obtained through an experimental curve that represents a static map, plotting steady state velocity with corresponding friction force. This static map (Figure 8) was obtained through many experiments carried out with velocity values being changed from around null velocity to maximum system value. These experiments were fulfilled with test apparatus configured as an open loop system, when a constant pneumatic valve opening possibilities that pneumatic actuator moves with constant velocity. In this case, acceleration values zero and friction force is equivalent to the resulting force produce in actuator by pneumatic force, given by Equation (4) subtracted from the load force required to drive the robotic mechanism. The identification of steady state friction (Fatri,ss) is important because we can consider at constant speed that the result of the forces in the pneumatic actuator is: Figure 8. Static friction-velocity map in steady state to pneumatic actuator with experimental values of the robot prototype for rehabilitation ssatripiLi FFf , \u2026\u2026\u2026\u2026\u2026\u2026(5) The Equation (5) is useful in force control with friction compensation of the pneumatically driven robotic workbench. As shown in Figure 4, the physiotherapist prescribes the desired movement trajectories for the exercise and the force limits that can be applied to the limbs. Then, from the signals of the angular displacement sensors and the force transducers mounted on the mechanism, the closed-loop control system performs the compensation calculations and sends the control signals to the pneumatic servo valves with the aim of maximizing the performance of the robot for rehabilitation." + ] + }, + { + "image_filename": "designv7_3_0004831_f_version_1576660043-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004831_f_version_1576660043-Figure1-1.png", + "caption": "Figure 1. The control and sensing system of the Shenzhen Institutes of Advanced Technology (SIAT) lower limb exoskeleton robot.", + "texts": [ + " In Reference [35,36], Pang employed KRLS in an FPGA to implement online non-linear regression. Inspired by the real-time and nonlinear properties of KRLS, this work employs KRLS to address the gait phase classification problem in the exoskeleton robot. In this section, the data acquisition platform is described, then the data source is described. After that, we show how we divided the gait phase and how to define the assist torque. Finally, the gait phase classification and prediction model is introduced. The data acquisition platform is shown in Figure 1. There are two kinds of sensors in this exoskeleton robot, the goniometers and the force sensing resistors. The lower limb exoskeleton designed by the Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Science called the SIAT exoskeleton was used in our experiments [37]. This exoskeleton was designed with the aim of helping the paraplegic patients to walk again normally or in the rehabilitation training for people suffering from lower limb injuries, such as accidents or strokes", + " In order to obtain the state information of the SIAT exoskeleton and use it for the controller to decide the following movement, goniometers are installed in the hip and knee joints to collect their angle information. The used goniometers are WDG-AM23-360, which can record the absolute angle range from 0 to 360 with 12-bit resolution. This means that angular measurement precision can be as high as 0.087\u25e6. Meanwhile, three force sense resistors (FSRs) are contained in an insole place in the shoes to detect the relationship between the foot and the ground. As shown in Figure 1, three FSRs are placed on the heel, middle and toe. The FSR 402 sensors equipped in our exoskeleton are produced by Interlink Electronics. FSR is a polymer thick film (PTF), shown in the bottom of Figure 1, whose resistance decreases when the force that is applied to the active surface increases. As the wearer walks in a gait cycle, the output voltage changes corresponding to the variation resistance of the FSR. The SIAT exoskeleton has two working modes\u2014power-assist mode and zero-torque mode\u2014which are used for different condition. The clutches are designed on each joint to switch between the two modes [33]. The power-assist mode offers enough torque to let the wearers walk in the predefined trajectory with the smart crutches to maintain balance" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001304_82703_FULLTEXT01.pdf-FigureB.3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001304_82703_FULLTEXT01.pdf-FigureB.3-1.png", + "caption": "Figure B.3. The final tetrahedral mesh of the bracket.", + "texts": [ + " Therefore a script was downloaded that orients the elements correctly automatically. The result can be seen in Figure B.1 below. The first step in meshing the structure surrounding the reinforcement, the bracket, is to mesh the inner surfaces so that the mesh is identical to the one used on the reinforcement. This is seen in Figure B.2. The next step is to create a triangular mesh on the remaining surfaces. A tetrahedral mesh was then created that matches both the triangular and the quadratic surface elements already created. The final mesh is seen in Figure B.3 below. The final volume to mesh is the middle piece of the bracket. The mesh of this volume has to match the bracket mesh where they are in contact. To do this the mesh on the contact surfaces was simply copied to the surfaces of the middle volume, see Figure B.4. Lastly the final surface was meshed and a tetrahedral mesh was created." + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000827_f_version_1624432525-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000827_f_version_1624432525-Figure7-1.png", + "caption": "Figure 7. No-load simulation of soft joint.", + "texts": [ + " To simplify the simulation, the joint was assumed to be a completely filled solid except for the inner channel, and to simulate the assembly of the real prototype, the soft joint model was assembled including its two support pieces, one at each end. After the design phase, the prototype was 3D printed using NinjaFlex material with 30% infill. The experiments were performed with this specific prototype. The model in SolidWorks was tested under different conditions. First, a no-load test was performed on the soft joint, by only simulating gravity and fixing one of the ends, as shown in Figure 7, with the red arrow representing the orientation of the gravity action in the simulation. One intended use of this soft joint is as a manipulator able to support different loads. Therefore, a second simulation was carried out with a rectangular prism with a fixed mass of 500 gr, homogeneously distributed. This prism represents the weight of the robot gripper in the simulation, Figure 8. In addition, a 10 Newtons downward force is applied to the end effector, simulating an external weight of 1 kg and causing a higher end torque" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001304_82703_FULLTEXT01.pdf-Figure3.16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001304_82703_FULLTEXT01.pdf-Figure3.16-1.png", + "caption": "Figure 3.16. The Front knuckle (red) with the brake caliper (green).", + "texts": [ + " Part data for the suspension fork. Suspension Fork Worst load case (Max) 1 Primary deformation type Compression Highest load size 38000N Load size direction (global) Z Design space (1-5) 3 3.3.6. Knuckles The knuckles, also known as wheel carriers, carries the wheel and allow the wheels to turn turning. The knuckle also carries the brake caliper and has to handle all loads arising from these attachments. Figure 3.13. The H-arm. Figure 3.14. The toe link. Figure 3.15. The suspension fork. The front knuckle can be seen in Figure 3.16. It is subjected to high loads from different directions causing the main load type to be hard to identify, therefore the load case can be considered as mixed. See Table 3.17 for part data. The majority of the loads are acting on the knuckles\u2019 lower part where the knuckle has a complex shape. This decreases the knuckles\u2019 potential to be successfully redesigned into a composite component. Due to the complexity of this component together with the high loads it will not be considered for future study in this report" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001623_0.1145_271283.271306-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001623_0.1145_271283.271306-Figure5-1.png", + "caption": "Figure 5: Work surface angle.", + "texts": [], + "surrounding_texts": [ + "Systems such as the Immersive Workbench are ideally suited to collaborative applications. A virtual model effectively sits on the Workbench and people naturally come over to look at the models. Using the Duo, recently developed by Fakespace, it is now possible for more than one person to see the virtual model correctly.This means that the collaborative virtual model space exists simultaneously for several viewers. The Responsive Workbench developed at GMD, the Immersive Workbench and other projection-based displays such as the Cave were typically restricted to a single interactive viewer and a number of passive participants. The interactive user wears both flicker stereo glasses (typically from StereoGraphics) and a head tracker. Software updates the perspective view to account for the motion of the viewer. Other people looking at the same display also wear stereo glasses and see the same stereo pair as the person with the head tracker. Unfortunately the stereo illusion works for the non head-tracked viewers only when their viewpoint is substantially the same as the headtracked person. One of the key issues cited in research on virtual projection displays is the effect of tracker error on the perceived quality of the environment. Of course, any error correction and measurements are performed relative to the participant who is wearing the head tracker. Even the errors in current tracking technology cause concern for creating a good quality virtual display. Issues such as calibration and lag are deemed essential items for future work. The errors for those participants who do not have the head tracker are enormous.The views they are seeing are calculated for a point of view which is several feet from their actual position! Issues such as tracker lag are totally irrelevant to the passive participants. This reduces the true utility of these systems which have been touted as collaborative design spaces even though there is only one good view. Given that systems such as the Immersive Workbench and Responsive Workbench are so well suited to collaborative design applications in principle, Fakespace has released the Duo for the display of multiple stereo pairs on a single projection surface.Thus, a number of stereo views are projected onto the work surface, and using special shutter glasses, the correct views are seen by the various participants. Initially, this technology has been implemented to support two independent stereo views. Figure 3: An easy to share workspace at Stanford University. The position and location of the workspace are also critical design decisions in these projection-based systems. The workspace should invite you to reach out into the model to point things out to a co-worker and interact with the model. Basically, the workspace needs to accommodate one's natural inclination to reach out and touch the model." + ] + }, + { + "image_filename": "designv7_3_0002823_f_version_1525349461-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002823_f_version_1525349461-Figure11-1.png", + "caption": "Figure 11. The two CIR LiDAR systems: (a) System 1; (b) System 2.", + "texts": [ + " The third dataset was used to verify the feasibility of the proposed method. Figure 10 is the rendered image of third dataset by elevation in which the walking ground wire was missing. The inspection objects in the third dataset mainly include a damper, insulator, and tree crown. There are no other inspection objects (e.g., attachment, broken strand) in the actual line with the naked eye. The three datasets were collected from two CIR LiDAR systems. The first and third datasets were collected by System 1, as shown in Figure 11a. A laser scanner was directly installed below the antenna, leading to blocking the upward scanning angle of LS, so that there was only a power line in the first dataset in Figure 8. The third dataset also misses the walking ground wire (in Figure 10). The second dataset was collected by System 2 in Figure 11b. The upward scanning angle of LS is not covered, and the installation size is beyond the minimum scanning distance of LS (1 m), so the dataset contains all power lines of the testing site (in Figure 9). Table 2 summarizes the specifications of the three datasets in terms of the two LiDAR systems, the number of points, and the densities and dimensions of the covered areas. The three datasets can show that the magnitude of CIR LiDAR datasets is large, for a span segment of a point cloud over 107. The point cloud density is more than three orders of magnitude of the ALS point cloud, providing a strong foundation for precise inspection object recognition" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001330_2_en.1998.1.2004.pdf-Figure5.14-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001330_2_en.1998.1.2004.pdf-Figure5.14-1.png", + "caption": "Figure 5.14: a) connection located outside critical regions; b) overdesigned connection with plastic hinges shifted outside the connection; c) ductile shear", + "texts": [ + "10 as follows: precast systenl able to satisfy all those provisions; precast systenls which are conlbined with cast-in-situ columns or walls in order to satisfy all those provisions; precast syste111s which deviate from those provisions and, by way of consequence, need additional design criteria and should be assigned lower behaviour factors. c) Identification of non-structural elelnents, which 111ay be: - conlpletely uncoupled t1'om the structure; or partially resisting the defonnation of structural elements. d) Identification of the effect of the connections on the energy dissipation capacity of the structure: connections located well outside critical regions (as defined in 5.1.2(1)), not affecting the energy dissipation capacity of the structure (see 5.11.2.1.1 and e.g. Figure 5.14.a); - connections located within critical regions but adequately over-designed with respect to the rest of the structure, so that in the seisll1ic design situation they renlain 128 BS EN 1998-1:2004 EN 1998-1 :2004 (E) elastic while inelastic response occurs in other critical regions (see 5.t 1.2.1.2 and e.g. Figure 5.l4b); ~- connections located within critical regions with substantial ductility (see 5.11.2.1.3 and e.g. Figure 5.14c) and 5.l4d\u00bb.@j] connections of large panels located within critical regions (e.g. at ground floor); and d) ductile continuity connections located within critical regions of frames 5.11.1.3 Design criteria 5.11.1.3.1 Local resistance (1) In precast elelnents and their connections, the possibility of response degradation due to cyclic post-yield defonnations should be taken into account. Norn1ally such response degradation is covered by the n1aterial partial factors on steel and concrete (see 5.2" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004287_35981_FULLTEXT01.pdf-Figure19-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004287_35981_FULLTEXT01.pdf-Figure19-1.png", + "caption": "Figure 19: (a) The mesh and boundary conditions for the corner with different plate thicknesses (one and five millimeters) when loaded in the plane at the thick edge. (b) The boundary conditions for the shell model. The numbers indicate which d.o.f. that are locked.", + "texts": [ + " 17 Two cases will be investigated for the corner, one where the two adjacent plates have the same thickness (figure 18a and 18b) and one where they do not (figure 18c). For the case of both plates having the same thickness the geometry of the plate is according to figure 17a and it is loaded is according to figure 17c. One of the loads is applied at a time and the non loaded edge is fixed in all d.o.f. Just as for the thickness variation models the load is equally distributed over all end nodes, see figure 19, and their magnitudes are: T = N = 10 N and M = 10 Nmm. The thickness of the plates is allowed to change from one to six millimeters with one millimeter increments throughout the simulations. 18 For the case of the plates having different thicknesses one is held constant (t1 in figure 17d) at one millimeter while the other (t2 in figure 17d) is allowed to change from two to seven millimeters with one millimeter increments throughout the simulations. The geometry of the plates can be seen in figure 17b. In this case two ways of loading are of interest. One when loading the thicker plate and one when loading the thinner plate. The edge that is not loaded is fixed in all d.o.f. and the loads used are the same three as in the case of the plates having the same thickness. The thick edge is loaded according to figure 17c and the thin edge according to figure 17d. Note that all loads are applied (distributed) in the same manner as in figure 19 for both edges. The solid model make use of eight-node cubic elements and the mesh can be seen in figure 19a. The shell models have a mesh consisting of quadratic elements with a side length of 0.25 mm. The material used is steel with Young\u2019s modulus E = 210000 Mpa and Poisson\u2019s ratio \u03bd = 0.3. 19 As a final confirmation of the conclusions made for the simpler geometries a real component is to be investigated using a combination of midsurface and offset modeling. Meaning that both offset and non-offset elements will be present. This is then to be compared with a solid model. The component to be investigated is a part of a C-bar, henceforth referred to as C-bar, which is depicted in figure 2" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001283_7339444_10494869.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001283_7339444_10494869.pdf-Figure1-1.png", + "caption": "Fig. 1. Flexible Shaft Construction and Characteristics", + "texts": [ + " In Section III, the experimental investigation of flexible shaft-based transmission and elastic element for robot arm using a test bench are provided and discussed. Section IV discusses the 3-DOF robot developed using a flexible shaft in three subsections: design, modeling, and control. Section V discusses the research outcome and concludes the paper with future work propositions. The flexible shaft is constructed by tightly winding multiple wire coils of variable radius of helices on top of each other around a core wire as shown in Figure 1(a) and (b). The winding direction of adjacent coils is kept opposite to give a bi-directional transmission potential as shown in Figure 1(a). With the increased radius of wires and the flexible shaft\u2019s global radius, D/2 as shown in Figure 1(a), the torque transmission capability is increased at the cost of less bending compliance. Like traditional springs, the increase in length, L and decrease in diameter, D results in decreased torsional and bending stiffness. Due to its bending compliance, once a torque is transmitted, it undergoes a helical buckling, as shown in Figure 1(c), causing reaction pull forces on the motor and load attachments. To stabilize this behavior, a geometric constraint-based stiffness is introduced around the flexible shaft as a flexible conduit with bearings at the end for relative rotation, as shown in Figure 2. The conduit ends are designed to provide connection fixtures for the source and load ends. A conduit with a high torsional and low bending stiffness is an ideal selection for the flexible shaft. The conduit used is made of rubber sheath and flat strip metal coil, which restrains the helical buckling of flexible shaft to assist the transmission of torque" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002698_12235_FULLTEXT01.pdf-Figure18-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002698_12235_FULLTEXT01.pdf-Figure18-1.png", + "caption": "Figure 18. weld stress, for assessment of weld root cracking.", + "texts": [ + " A simple rule to obtain the nominal stress is to extrapolate the linear part of the stress on the surface inwards against the weld, see Figure 17. In the example below the nominal stress could easily be determined but in most cases the reality never looks like in the fatigue codes. 3.1.5. Nominal stress at weld root /throat When the weld is sensitive to fatigue root cracking the analysis should be based on stresses at weld throat by calculating the weld weld stress \u03c3n,w. The weld stress is based on average stress components in the weld throat (similar to static design), see figure 18; the stress \u03c3\u2534 is the normal stress to the weld throat section, the stress \u03c4\u2534 is the normal stress to the weld throat section. For cruciform joints and T-joints the weld stress can be calculated according to the following equation: (\u03c3nt) is the axial force in the plate and (2a) is the weld throat. 3.1.6. Km modification due to misalignment Misalignment in axially loaded joints leads to an increase of stress in the welded joint due to the occurrence of secondary shell bending stresses. The resulting stress is calculated by stress analysis or by using the formulae for the stress magnification factor km given in Table 2" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000549_f_version_1722761863-Figure24-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000549_f_version_1722761863-Figure24-1.png", + "caption": "Figure 24. Movement state after steering.", + "texts": [ + "3, and the overall walking speed of the robot is simulated. The simulation speed curve is shown in Figure 21. Focusing on the designed mobile foot robot, its steering movement is analyzed. Before turning, its walking state is as shown in Figure 22. After advancing a certain distance, the closed-chain leg mechanism begins to turn. In the process of steering, the motion state is as shown in Figure 23. According to the rotation angle of the driving rod, the foot-type mobile robot can realize steering as a whole, and its motion state is as shown in Figure 24. To summarize, it is possible to theoretically simulate the various motions of the designed foot-type mobile robot through software modeling, which can realize the motion state analysis of the mechanism under different conditions. Furthermore, we can intuitively analyze the movement of the foot end, providing conditions for the installation and optimization of the foot-end trajectory. The walking stability of the robot is one of the most important indices in the design process, and the stability of the robot\u2019s motion can be analyzed by observing the fluctuations of the drawn center of the robot\u2019s mass" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003817_8600701_08766968.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003817_8600701_08766968.pdf-Figure3-1.png", + "caption": "FIGURE 3. Illustration of the rotation matrix.", + "texts": [ + " R(x) is a rotation matrix designed so that aTx R(x)d\u0302(x\u0302b) = 0 (31) where ax = \u03b21yTKy(J\u0302 W\u0302+)\u221211F + ap(1\u03bb + \u03b31F), ap = J\u0302 (q\u0307\u2212 z\u0302cW\u0302+(y\u0307d \u2212 \u03b11y)). We can rewrite the position of the end effector xb as xb = [xTbp,x T bo] T , where xbp denotes the position vector and xbo denotes the orientation vector. Thus, ax can be partitioned as ax = [ aTxp, a T xo ]T . d\u0302(x\u0302b) can also be written as d\u0302(x\u0302b) =[ d\u0302Tp (x\u0302b), d\u0302 T o (x\u0302b) ]T . Then, we can define the rotation matrix R(x) as R(x) = [ Rp(np, \u03c6p) 0 0 Ro(no, \u03c6o) ] (32) where np is a unit vector normal to both the vectors axp and d\u0302p(x\u0302b) as shown in Fig.3, \u03c6p is the angle between d\u0302p(x\u0302b) and Rp(np, \u03c6p)d\u0302p(x\u0302b), which can be determined from the angle \u03c6 between d\u0302p(x\u0302b) and axp, the vector d\u0302p(x\u0302b) is rotated by the rotation matrix Rp(np, \u03c6p) about the axis np, so that the vector Rp(np, \u03c6p)d\u0302p(x\u0302b) is perpendicular to the vector axp, as illustrated in Fig.3. Here, the symbol \u00d7 represents cross product. We can design the rotation matrix Ro(no, \u03c6o) by the similar way. In fact, the constraint surface is usually independent of xbo. Thus, we can set the rotation matrix Ro(no, \u03c6o) as an identity matrix. Remark 1: ax and d\u0302(x\u0302b) are all known vectors which can be obtained by using the estimated parameters J\u0302 , W\u0302 , z\u0302c and the measurement parameters q\u0307, y, yd , y\u0307d , \u03bb, \u03bbd and 1F . Therefore, there must be a matrix which can rotate a known vector to perpendicular to another known vector" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001154_6514899_10231152.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001154_6514899_10231152.pdf-Figure1-1.png", + "caption": "Figure 1: Free-body diagram of two-wheeled self-balancing.", + "texts": [ + " MATHEMATICAL MODEL This section presents the nonlinear mathematical modeling of the two-wheeled self-balancing mobile robot. The model is based on the works published in [28], [43], [44]. Some considerations are made: noise, engine wear, road resistance, vibration, wind, and friction between surfaces/wheels are modeled as endogenous and exogenous disturbances. These disturbances will be estimated by the ESO and eliminated by the control action in conjunction with the observer. Consider the free-body diagram in Fig. 1. According to Newton\u2019s second law, the following equations give the equations that describe the dynamics of the inverted pendulum angle and the displacement of the mobile robot. m1(x\u0308 \u2212 l sin\u03d5\u03d5\u0307+ l cos\u03d5\u03d5\u0308) = FH (1) m1(\u2212l cos\u03d5\u03d5\u0307\u2212 l sin\u03d5\u03d5\u0308) = FV \u2212 m1g (2) J \u03d5\u0308 = FV l sin\u03d5\u2212 FH l cos\u03d5 (3) m2x\u0308 = u\u2212 FH (4) where x and \u03d5 define the state variables of our system. x represents the displacement of the robot, and \u03d5 represents the angle of the bar of pendulum. The horizontal and vertical forces on the chassis are defined by FH and FV , respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001177_06044_FULLTEXT01.pdf-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001177_06044_FULLTEXT01.pdf-Figure13-1.png", + "caption": "Figure 13: ABB IRB 7600-255 robot dimensions, required for the kinematic model [62]", + "texts": [ + " This section will describe in more detail the development of a kinematic model, applied to the robot used throughout this thesis. A common method to describe the kinematical chain of a robot is by using the Denavit-Hartenberg (DH) parameter notation [60]. This describes each transformation from one robot joint to the next by a set of four parameters: two distances (a, d) and two angles (\u03b1, \u03b8). A kinematic model for the ABB IRB-7600 robot is identified using the typical DH-parameters and the robot dimensions, provided by ABB, as shown in Figure 13. The DH-parameters for this robot are provided in Table 1. Previous research has also adopted this approach to identify a kinematic and dynamic model of this type of industrial robot [61]. 31 Once the parameters are identified for each of the joints, they can be transformed into a \u201chomogeneous transformation matrix\u201d, \ud835\udc47\ud835\udc470\ud835\udc61\ud835\udc61. This matrix describes the transformation from the robot base frame (index 0) to the tool frame (index t) in a [4\u00d74] matrix, consisting of a [3\u00d73] rotational part, R and a [1\u00d73] translational part \ud835\udc43\ud835\udc43 = [\ud835\udc65\ud835\udc65,\ud835\udc66\ud835\udc66, \ud835\udc67\ud835\udc67]\u2032 in equation (3)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001650_32489_FULLTEXT01.pdf-Figure20-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001650_32489_FULLTEXT01.pdf-Figure20-1.png", + "caption": "Figure 20.Transmitting Angles (Alipiev, 1988)", + "texts": [ + " The value of can be found by the following equation: [ \u221a ( ( ] (Eq 2.1.64) 27 Biser Borislavov, Ivaylo Borisov, Vilislav Panchev This angle depends on the angle \u03c8 and on the coefficient of displacement x. In Figure 19 it has been build the relation of in respect of \u03c8 with different coefficient of displacement x. It is obvious that its maximum value is 90\u00b0 and it can be as positive as negative. - Transmitting Angles The transmitting angle is between the directors of the force \u20d7\u20d7 \u20d7\u20d7 \u20d7 and the speed \u20d7\u20d7 \u20d7\u20d7 \u20d7 (see Figure 20). It is clear that this angle depends on \u03c8. The transmitting angle is important because of possible jamming and it must fulfil the following condition: Sometimes it is better to use the angle \u03b3 instead of \u03b8. The angle \u03b3 is called angle of motion transfer and it is the supplementary of to .And in this case the equation will be: Where the angle \u03b3 can be found by looking at triangle and using the sine theorem: \u0305\u0305 \u0305\u0305 \u0305\u0305 : [ ( \u221a ( ( ] (Eq 2.1.65) 28 Biser Borislavov, Ivaylo Borisov, Vilislav Panchev In Figure 21 it is shown the change of \u03b3 according different stages of ( ( " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003849_f_version_1556450254-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003849_f_version_1556450254-Figure2-1.png", + "caption": "Figure 2. A simplified model of the right front (RF) leg.", + "texts": [ + " To calculate the energy consumption of the robot, the following preconditions are made: (a) Only the motions in the sagittal plane are studied. The robot is walking on a flat surface with the trot gait. (b) When walking on a flat surface, the height change of the robot trunk\u2019s center of mass (COM) is ignored. (c) The trunk of the robot can be regarded as a cuboid, and its COM is assumed to be at the geometric center of the body The legs of the robot have the same structure and mechanical parameters. Here, the right front (RF) leg is used as an example. The single leg model is shown in Figure 2. According to precondition (a), the motions of the rolling hip joint are not considered and the rolling hip joint position is set as 0. In Figure 2, the RF leg can be divided into the hip, thigh, and shank parts. Since the motions of the rolling hip joint are neglected, the hip part can be regarded as the base. The origin of the coordinate frame {Oh} is set at the rolling hip joint. The z-axis direction is vertical to the ground facing upward. The x-axis is pointing to the motion direction of the robot. The mechanical parameters in Figure 2 are introduced as follows. The lengths of the hip, thigh, and shank parts are l0, l1, and l2 respectively, where l0 = 45 mm. m1 and m2 are the masses of the thigh and the shank parts, respectively. The joint positions of the pitching hip and pitching knee joints are denoted as \u03b81 and \u03b82, respectively. The COMs of the thigh and shank parts are defined by lm1, lm2, \u03b51, and \u03b52. When the thigh and shank parts rotate around their own joint shafts, the moments of inertia are I1 and I2, respectively. The values of these mechanical parameters are listed in Table 1 [12]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004310_7042252_07312395.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004310_7042252_07312395.pdf-Figure1-1.png", + "caption": "FIGURE 1. A frame of reference of ground vehicle dynamics.", + "texts": [ + " In this context, a coordinated operation of automotive chassis and powertrain systems undertake the function of controlling the vehicle motion to enhance safety, eco-friendliness, comfort and other vehicle characteristics. IMC application areas relate not only to the traditional transportation sector of passenger cars and commercial vehicles but also to agricultural, mining, construction and forestry machinery. The IMC systems are also substantial components of automated driving, which has dartingly increased importance for the future transportation paradigm. The integration of active chassis and powertrain systems can be considered in relation to three domains of vehicle dynamics, Fig. 1. From this standpoint the IMC can specifically address longitudinal, lateral and vertical motion of the vehicle or can have cross-domain applications. By the cross-domain application is meant that integrated systems are targeting simultaneous improvement of the performance in terms of parameters related to vehicle dynamics in XY-, XZ-, YZ- or even XYZ-frame of reference. Basic works related to the IMC have originated in the middle of 1980s. In particular, Fruechte and co-authors have introduced in [1] the results of General Motors project Trilby, where global integration architecture for various vehicle subsystems has been developed, Fig", + " However, an extended survey of various IMC configurations in relation to longitudinal, lateral and vertical dynamics of the vehicle is not found from the analysis of available research literature. Therefore the presented paper has an intention to close this gap and will discuss the following topics in next sections: IMC classification in relation to a frame of reference of vehicle dynamics; overview of IMC systems; overview of methods for integration of active chassis and powertrain systems. II. INTEGRATED MOTION CONTROL IN CONTEXT OF GROUND VEHICLE DYNAMICS A frame of reference of vehicle dynamics form Fig. 1 can be used as a basis for IMC classification. In that case the classification includes seven possible classes, which can be called hereinafter as X-, Y-, Z-, XY-, YZ-, XZ-, and XYZ-integration for convenience. The X-integrationmeans a combined operation of systems for the purposes of longitudinal vehicle dynamics control, e.g. braking or traction control. A case in point is the electric vehicle brake system integrating conventional friction brakes and electric motors operating in a regeneration mode" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-10-1.png", + "caption": "Figure 70-10. Road Wheel Load Diagram for Rigid Suspension Vehicle", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\nBecause the movement of the structural member is communicated to the vibration-damping material, the inherent effects of hysteresis in the former material are supplemented by the much higher hysteresis of the deadener material or by its dissipative effects of viscosity, fiber flexure, and internal friction, as well as the friction effects at the interface.\nA comprehensive presentation of the subject of vibration and noise control by applied damping treatments is found in Ref. 16.\n10-12.3 STRUCTURAL AND DESIGN MODIFICATION (Ref. 19)\nAnother approach to the problem of reducing or eliminating noise and vibration of military vehicles consists of structural and/or design modification.\nIf the forcing function is of the discrete spectrum type, it may be possible to shift the natural frequencies of the structure so that coincidence with the forcing frequencies is avoided. This may\ninvolve stiffening or weakening the structure. Another method of changing the natural frequencies is to add a spring and mass to the structure and, consequently, add another degree-of-freedom.\nIf the forcing function is of the discrete and/or continuous spectrum type, the addition of damping will reduce the response at the resonant frequencies.\nMethods of introducing damping through structural modification include: (a) replacement of the original material by another having higher internal dampening, (b) the addition of surface damping materials, and (c) the addition of slippage and, hence friction, between members.\nSince one of the principal sources of secondary disturbances and vibrations is the unsprung mass, and since wheel dance is one of the major sources of these disturbances, the amount of noise and vibration can be altered by varying factors such as the major springing system rate, the road wheel tire spring rate, the mass of the road wheel, and the damper characteristic. These factors are discussed in Sections VII and VIII of this chapter.\nSECTION V ROAD WHEELS AND HUBS 10-13 DESIGN CONSIDERATIONS\n10-13.1 NUMBER OF WHEELS REQUIRED The number of road wheels as a parameter in the soil-vehicle relationship is discussed in Part Two\u2014Land Locomotion. The present discussion concerns some of the mechanical aspects of the problem.\nThe number of wheels required varies with the weight of the vehicle. For example, the Main Battle Tank, M60 (102,000 lb) utilizes six dual 26 X 6 road wheels on each side, while the Heavy Tank, T43 (120,000 lb) utilizes seven dual 26 X 6 road wheels on each side. Thus, each dual wheel assembly supports approximately 8,500 pounds if a uniform load distribution is assumed. However, even under static conditions, the loading of the road wheels of a conventional vehicle may not be uniform owing to the location of the center of gravity. Further changes in loading occur as a result of the dynamic conditions experienced by a vehicle.\nIncreasing the number of road wheels to compensate for increase in vehicle weight sometimes results in a decrease in suspension efficiency. However, a decrease in efficiency may be outweighed by advantages obtained in using standardized interchangeable components. Currently, two standard sizes of road wheels are in use: 26 X 6, usually employed on medium and heavy tanks, and 25V2 X 4V2, used on light tanks.\nAnalytical studies and empirical data show that rolling resistance for a tracked vehicle decreases as the number of road wheels increases (Ref. 20). However, since the number of wheels is limited by track length, the specification of a large number of wheels dictates that either small wheels or overlapping wheels must be used. This problem is analyzed in Ref. 10.\n10-13.2 DIAMETER AND WIDTH Two fundamental design considerations related to the diameter of the road wheel are: (a) rolling\n10-12", + "AMCP 706-356\nThese subjects are discussed in Section XII of this chapter.\n10-13.3 SPACING Normally, the spacing of the road wheels of tracked vehicles is nonuniform within limits imposed by the number of wheels, the diameter of the wheels, and the length of the track. As a road wheel travels over a conventional track, it encounters a discontinuity in the running surface at each joint of the track. Noise, vibration, and wear are minimized if the road wheels do not encounter the track joints simultaneously. To accomplish this, the spacing of the wheels is correlated with the pitch of the track shoes.\n10-13.4 LOAD CALCULATIONS\nresistance, and (b) power lost as a result of the track link striking the ground.\nA number of investigators have shown analytically that ainkage and rolling resistance in soils are related to the diameter of the road wheels (Ref. 21). In general, an increase in road wheel diameter (other conditions unchanged) results in a decreased sinkage and rolling resistance.\nThe impacting of track links on the terrain is discussed in paragraph 10-11.3. Equation 10-15 of paragraph 10-11.3 shows that the power lost through the impacting varies inversely as the second power of the radius of the leading road wheel.\nThe width of road wheels enters into the general design considerations from the standpoint of the track and the wheels themselves. Since the track is wider than the wheels acting on it, deflection and transverse load distribution of the links must be considered. In addition, the bearing loads on the track and the wheels must be considered.\n10-13.4.1 Static Loads (Ref. 22) The load acting on each road wheel of a tracked vehicle can be determined by the methods that follow.\nFor the initial calculation, consider a vehicle having three equidistant road wheels on each side, a rigid suspension, and a loose track (as shown in\nThis assumption or condition concerns the sinkage of the wheels. Since the suspension is rigid, the sinkage will be such that the centers of the wheels will remain on a straight line. Furthermore, since the center of gravity is displaced to the left of the center wheel, the left wheel will tend to sink more than the right wheel as shown in Figure 10-10. This condition can be expressed as\nZt -Z2~Z2-Z3 (10-18)\nAs was discussed in Chapter 4, the sinkage Z(, in., for each wheel (assuming the area of the ground-contact of each wheel is the same) is given by\n10-13", + "AMCP 706-356\nwhere\nZ,\nFigure )0-?). Rood Wheel Load Diagram for Independently Sprung Vehicle\n^a= (\nxAk) (10-19)\nW2 \\ !/\" Ak) (10-20)\nw3y/\u00bb (10-21)\nW,; = load acting on each wheel, lb A = area of the ground-contact of each wheel,\nsq in. k = soil constant (see Chapter 4), lb/in.\"+2\nBy using the case of Bernstein's n = V2 and Equations 10-18 to 10-21, the following equation can be\nwritten\nThe solution of Equations 10-16, 10-17, and 10-22, yields the following values for the three unknown loads\nW, = 0.556 W\nW2 = 0.390 W\nW3 = 0.054 W\n(10-23)\n(10-24)\n(10-25)\n2F2 2 - Wf (10-22)\nThese equations show the influence of the location of the center of gravity on the distribution of the wheel loading.\nThe method described above may be extended\nto evaluate the loads on the road wheels of vehicles possessing spring suspension systems. The dis-\ncussion which follows is limited to individually suspended wheels; a thorough discussion of ve-\nhicles having nonindependent suspensions is found\nin Ref. 10.\n10-14" + ] + }, + { + "image_filename": "designv7_3_0001778_f_version_1539156502-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001778_f_version_1539156502-Figure4-1.png", + "caption": "Figure 4. The general appearance of the robot is designed to be integrated into the building\u2019s lobby, and resemble part of the architecture. The colours chosen are the official ones used from the company\u2019s brand. The robot has been designed to support ergonomic aspects that take into account accessibility and affordance.", + "texts": [ + " The App was designed to give notice to the receiver of the visitor\u2019s arrival, with the details received in the subscription form. In this way, the receiver would have been aware of the guest arriving and decide to welcome him/her and, in that case, send the robot to show the way to his/her office. Thus, the interface running for providing an optimized experience essentially consisted of three parts: the tablet in the kiosk, the tablet above the robot courier, and on the smart phone of the receiver inside the company\u2019s building as depicted in Figure 4. According to Dautenhahn [20], the concepts of perception and acceptance are central to HRI, since it is crucial for human partners to interact with the agents in an intuitive way. In the context where the social robots are used, especially in the case of social robots, they have to support people in everyday activities and perform tasks that are simple [60,61]. In order to design socially interactive robots, it is important that the tasks they can perform can be grasped as fast and intuitively as possible by the humans" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001206_f_version_1632980024-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001206_f_version_1632980024-Figure8-1.png", + "caption": "Figure 8. An example 2-DOF problem used to explore the challenges of searching the hypothesis space, H, for the global maximum sum of evidence solution, H?. (a) Geometry and measurements of the example two degree of freedom estimation problem. (b) The sum of conditional likelihoods of the nine range measurements evaluated across the hypothesis space, H = [\u03b81, \u03b82]. (c) Incorrect local maximum sum of evidence at pose HA.", + "texts": [ + " The sum of evidence measure described in Equation (9) requires the summation of conditional measurement likelihoods. As this paper will show, the evidence metric serves as a very robust objective function for the measure of hypothesis likelihood. A search heuristic is required to determine the hypothesis parameters that yield the maximum sum of evidence. This section explores search heuristic performance using an example 2D search space of a robotic manipulator. The example robot geometry is parameterised by the hypothesis space H = [0\u25e6 \u2264 \u03b81 \u2264 180\u25e6, 0\u25e6 \u2264 \u03b82 \u2264 180\u25e6] (Figure 8a). Nine range measurements, Z, are obtained from a sensor with the robot located by Htruth = [28.6\u25e6, 114.6\u25e6]. Figure 8b shows the evidence measure of Equation (9) mapped across the complete hypothesis space, H. The true hypothesis is shown to produce the global maximum sum of evidence, H?, at the correct location, Htruth. An immediate concern, however, is that many local maximums of evidence exist within this surface. Other robot configurations, such as H A (Figure 8c), are reasonably well evidenced from the range measurements and will result in local maximums. Incorrect pose hypotheses (such as H A) can have considerably large basins of convergence. Figure 9b shows the basin of convergence for hypotheses H? and H A. The basins were determined by examining the solutions of a Nelder-Mead solver (with side length 10\u25e6) seeded in 1\u25e6 increments of the hypothesis space, H. Approximately 18% of the seed locations are shown to converge to the MSOE hypothesis, H?, however, 11% were also shown to converge to the competing local maximum, H A" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure5.15-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure5.15-1.png", + "caption": "Figure 5.15 Forklift with 2000kg load", + "texts": [ + "5 Mass Property of Subassembly: Lifting Fork (P83) Figure 5.6 Mass Property of Subassembly: Scissor Lift (P84) Figure 5.7 Mass Property of Forklift Assembly (P84) Figure 5.8 Mass Safety Zone of Forklift (P85) Figure 5.9 Front View of Forklift\u2019s Center of Mass (P86) Figure 5.10 Top View of Forklift\u2019s Center of Mass (P86) Figure 5.11 Top View of Forklift with Stability Triangle Dimension (P87) Figure 5.12 Adjusted Stability Triangles (P88) Figure 5.13 Forklift with 3000kg load (P89) Figure 5.14 Mass Center Positon under 3000kg Load (P90) Figure 5.15 Forklift with 2000kg load (P91) Figure 5.16 Mass Center Positon under 2000kg Load (P92) Figure 6.1 Loading Part Analysis Demonstration (P95) Figure 6.2 Fork Meshing Model (P96) Figure 6.3 Boundary Condition (P96) Figure 6.4 Stress Result of the Fork (P97) Figure 6.5 Strain Result of the Fork (P97) Figure 6.6 Displacement of the Fork (P98) Figure 6.7 Maximum Von Mises Stress Result of the Fork (P98) Figure 6.8 Fatigue Checking of the Fork (P99) Figure 6.9 Meshing Model Using Moderate Elements (P100) Figure 6", + " And then we do a whole assembly mass calculation to the forklift, the result is shown in Figure 5.14. It shows where the mass center is located now. As we can see from Figure 5.14, the mass center of the truck is out of the safety zone (between two black lines), which means under this loading condition, the forklift is not safe. Apparently, the 3000kg weight load is too much for our forklift, so we need to adjust the load we apply. After we change the weight of load a few times (2800kg, 2500kg, 2300kg and 2100kg), finally when the load comes down to 2000kg, as shown in Figure 5.15, we get the result we want: the mass center position stays inside the safety zone. The result of mass calculation is shown in Figure 5.16. As we can see, the center of mass is within those two black lines, which means the truck is balanced at load of 2000kg. Based on the results of the loading test we did above, we can say that our forklift\u2019s maximum loading carrying capacity is 2000kg. Usually in a warehouse, we won\u2019t put such a heavy cargo on the shelf. As to say the forklift won\u2019t pick up such load typically" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003149_eureca2018_02023.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003149_eureca2018_02023.pdf-Figure7-1.png", + "caption": "Fig. 7. Prototype Mission Profile.", + "texts": [ + " The final build of this proposed prototype is roughly shown in Figure 6 where in the future, minor modifications may be necessary. 3.3 Test Protocol The prototype would be conducted in both manual and autonomous flights. The UAV would take off vertically in vertical flying mode, then perform transition to horizontal flying mode, fly straight and level to a certain designated waypoint, then perform transition to vertical flying mode again and finally land the UAV safely. For a manual flight, a ground user would pilot the UAV via radio control transmission. This mission profile can be simply visualized as in Figure 7 below. 8 From Figure 7, the biggest challenge is to perform the transition flight from horizontal flight to vertical flight mode and vice versa. During this portion of the flight, the UAV may lose some altitude due to the reduction in lift force vector while slowing down the vertical motors. Hence, the horizontal motors need to produce enough thrust to accelerate the UAV quickly for the wings to replace the vertical motors in generating lift. Another method to address this possible altitude lose is to develop an effective control system where the vertical motors would continue to generate enough lift while in transition until it passed the minimum stall speed", + " It is important to determine the right AUW for the prototype as the subsequence design calculations are based entirely on this parameter see Table 1. Hence, AUW would be estimated a bit higher than the calculated value to be 3.5 kg. 3.6 Wing Design First, Wing Loading, Wl is to be calculated (Equation 1). \ud835\udc4a\ud835\udc4a\ud835\udc59\ud835\udc59 = \ud835\udc34\ud835\udc34\ud835\udc34\ud835\udc34\ud835\udc4a\ud835\udc4a \ud835\udc46\ud835\udc46\ud835\udc4a\ud835\udc4a (1) The wing loading needs to be as low as possible to ensure minimum stress exerted during flight can be sustained by the wing. Wing loading value is more important than the actual weight of the aircraft because it tells how much weight is 8 From Figure 7, the biggest challenge is to perform the transition flight from horizontal flight to vertical flight mode and vice versa. During this portion of the flight, the UAV may lose some altitude due to the reduction in lift force vector while slowing down the vertical motors. Hence, the horizontal motors need to produce enough thrust to accelerate the UAV quickly for the wings to replace the vertical motors in generating lift. Another method to address this possible altitude lose is to develop an effective control system where the vertical motors would continue to generate enough lift while in transition until it passed the minimum stall speed" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000612_f_version_1684247699-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000612_f_version_1684247699-Figure8-1.png", + "caption": "Figure 8. U-turn of the field experiment for the navigation of the experimental robots (the road end point is the center point of the last two trees). The steering path was planned according to the distance from the tree trunk.", + "texts": [ + " When the proportion was greater than the set ProT or reached the set maximum operation time, the calculation of the RANSAC algorithm was completed (Figure 7). The vehicle was guided at the forward speed until it reached the end of the tree rows, and the number of tree trunks was not enough to use the above method for trajectory planning. In this study, when the vehicle was operated at the road end point (the midpoint of the last two trees), the vehicle steering angle was set based on the distance to the trunk from the LiDAR system (Figure 8). Vehicle steering was started, and the LiDAR system continued to scan the surrounding environment information. DBSCAN and K-means were used to continue to distinguish the location of the surrounding trunks. Until the vehicle was turned to the next road in which the left and right sides obtained enough points returned from the tree trunk, the steering ended and continued to operate according to the path planning algorithm. 2.4.1. Trajectory Tracking Control The path tracking of the robot was divided into three types according to the model used: kinematic-model-based path tracking, dynamic-model-based path tracking, and path tracking that does not require a model" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002726_4_Paper22103-108.pdf-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002726_4_Paper22103-108.pdf-Figure8-1.png", + "caption": "Fig 8 At 288.62 Hz", + "texts": [ + " We applied the boundary conditions and imposed the structure to vibrate at various frequency, it was considered that the frequency at which there would be major deformation ,it would be its natural frequency. Table 2 Frequency at each calculated Mode Fig 9 Frequency at each calculated Mode We did model analysis to find natural frequency of anti vibration mount structure. Following figures shows total deformation in mount structure for each frequency. The frequency at which deflection of structure is maximum gives the natural frequency of the structure of anti vibration mount. In this case maximum deflection of structure shows in fig. 8 at frequency of 288.62 Hz.Thus to avoid resonance ,te mating of natural frequency should be avoided. Transient dynamic analysis is a technique used to determine the dynamic response of a structure under a time-varying load. The time frame for this type of analysis is such that inertia or damping effects of the structure are considered to be important.Cases where such effects play a major role are under step or impulse loading conditions, for example, where there is a sharp load change in a fraction of time" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002287_9159950_09018154.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002287_9159950_09018154.pdf-Figure3-1.png", + "caption": "Fig. 3. Hanging mechanisms on roller can lock onto one ceiling hole only.", + "texts": [ + " Hanging mechanisms for mechanical attachment to the ceiling plate are mounted on the crawler mechanism, and HanGrawler achieves continuous movement by locking onto and releasing from the ceiling plate using the hanging mechanism. To achieve continuous movement, the robot must use a mechanism that achieves both contact and fixing between the hanging mechanisms and ceiling plate, such as a roller or crawler. If the hanging mechanisms are mounted on the circumference of a roller, the adjacent hanging mechanisms cannot lock onto the holes because there is only one contact point or line (see Fig. 3). Therefore, multiple rollers are necessary for stable attachment. However, if multiple rollers are installed, the robot configuration becomes complex, because the robot must synchronize the rotation of multiple rollers and the hanging-mechanism locking/release motions. In contrast, for hanging mechanisms mounted on the circumference of a crawler mechanism, the robot can lock onto multiple ceiling-plate holes because the crawler establishes plane contact with the ceiling plate. Thus, the robot can switch between multiple hanging mechanisms during movement without synchronizing multiple mechanisms, because the crawler mechanism is a unitary structure" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004741_tr_pdf_ADA595226.pdf-Figure31-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004741_tr_pdf_ADA595226.pdf-Figure31-1.png", + "caption": "Figure 31 - Angle change representation", + "texts": [], + "surrounding_texts": [ + "Two steering heads comprised of the same components were developed the only difference being the location of the pneumatic muscles on the head. The range of motion between the two was analyzed for optimal flex/travel (Figure 30). The steering head consists of a tail regulator manifold which reduces the high pressure line down to 40psi, a solenoid valve bank for controlling each muscle individually, and a pneumatic muscle assembly allowing 8 possible directions (Figure 30). Page 23 of 47" + ] + }, + { + "image_filename": "designv7_3_0000428_0120959_WLA_0086.pdf-Figure1-4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000428_0120959_WLA_0086.pdf-Figure1-4-1.png", + "caption": "Figure 1-4 Illustration of the quadrotor drone with creative design. (a) Drone with tilt rotor", + "texts": [ + " On the other side, it refers to the software researches about the creation of quadrotor drone model aiming to examine different control strategies [40-43] relative to the software installed in the drone regarding perfecting the control methods of PID, LQR, backstepping feedback, sliding mode and the integration of these methods [44-47], enriching the controller utilizing vision control of compound eye or cinema [48,49], and integrating different control strategies for autonomous mission or swarm communication [50,51], which aims to promote the stability, agility and controllability of drone [52-54]. Furthermore, as the development of lightweight materials, manufacture, and sensors, as well as the great progress in flight dynamics, control, navigation, and lift capabilities [1], it makes some creative concepts and designs of quadrotor drone to be feasible and realizable, which is potential for improving the flight controllability of quadrotor drone, such as tilting propeller [55-59], potable fuselage [60], and ducted propeller [61-64] as depict in Figure 1-4. Chapter 1.1 Introduction of drone 3 Beyond these previous researches, it is still significant and meaningful to improve the aerodynamic performance of drone due to its increasingly extensive application in different fields, which aims to realize the long endurance of the flight, the less cost of the power, and the high efficiency of the drone system. Thus, we exert ourselves to improve the aerodynamic performance of quadrotor drone from the enlightenment of biomimetics that provides some bioinspired concepts for the design of quadrotor drone from the exquisite flight performance of flying birds or insects [65-69]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002325_f_version_1403313975-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002325_f_version_1403313975-Figure9-1.png", + "caption": "Figure 9. Scanning process.", + "texts": [ + " In the reconstructed clouds of points the gauge holes are segmented and measured and the measurement results are compared with the measurement using a CMM. The direction selected is the one that minimizes the distance error between the centres measured using a CMM and the ones reconstructed with the LTS, Table 4. using the camera 2 images. Once calibration of the LTS has been performed with the captured images of the LTS-gauge, the points in the laser line are known in the global frame of the LTS and the part surfaces can be scanned (Figure 9) using a robot to positioning each surface in the field of view of the LTS (Figure 10). This section shows a method for measuring the different surfaces of the part and establishes the position of each element in the frame of the part avoiding using robot data. Sensors 2011, 11 102 The measurement process is divided in six stages: data acquisition, image analysis, reconstruction of the cloud points and analysis for each element of the part, coordinate system transformation to express point coordinates of each element in the reference system of the part and, finally, result analysis" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001935_f_version_1616408528-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001935_f_version_1616408528-Figure9-1.png", + "caption": "Figure 9. CAD images of two candidates, with the different placements of joints G and H: candidate 1 designed to be located behind the thumb, and the candidate 2 designed to be located beside the wrist.", + "texts": [ + " Regarding the third actuator placement, if it is installed near the palm or the surface, the structure of the base part will be complex and there is the possibility that the collision between chains 3 and 1 or 3 and 2 occur. For this reason, the probable placement is chosen as near to the wrist. However, because the placement of the actuator affects the size of the reachable workspace, the placement is must still be considered in more detail. For the third actuator placement, two models were considered, as shown in Figure 9. Those candidates are designed with the third actuator placed near the wrist, but the detailed placements are different. In the first candidate, the third actuator is placed on the side of the wrist. In the coordinate system in the figure, the third actuator\u2019s position of the xy plane matches the origin point. In the second candidate, the placement of the third actuator is designed to be nearby the wrist. Based on the above-mentioned coordinate system, its actuator position of the xy plane is not in the origin point" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004507_f_version_1657175254-Figure10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004507_f_version_1657175254-Figure10-1.png", + "caption": "Figure 10. Prubot\u2019s reachable workspace in different views.", + "texts": [ + " Therefore, the word \u201cwall\u201d does not invoke a static wall, but rather it is an integral part of a platform. The vine and trellising dimensions that are introduced in Section 4 are also used for modeling the robot task space. However, due to attaching an end-effector to the manipulator, it is vital to fine-tune the position of the manipulator\u2019s shoulder through simulations. It led to an increase in R (i.e., the distance of Prubot\u2019s shoulder from the vine trunk) from 0.8 to 0.96 m. Prubot\u2019s reachable work space is shown in Figure 10 in which 300,000 feasible positions are illustrated by 300,000 random cloud points. The work space contains a vine completely. Simulations indicate that to cane prune a vine row from both sides completely, two Prubot manipulators located symmetrically with respect to the crop row are required because the trellising system practically blocks the manipulator\u2019s access to the other side of the row. In Figure 11, the dimensions of the task space of a grapevine-pruning robotic system with two Prubot manipulators are illustrated", + " Note that in both test 1 and test 2, a path planning trial is considered to fail if a collision happens or the path planning calculations fail. Although the simulation algorithm script is not an optimized one and it does not lead to a trajectory planning result (the differences between path planning and trajectory are clarified in [48]), it still can be a good tool for evaluating Prubot\u2019s kinematic performance and estimating the sampling-based path planning algorithms\u2019 performance for Prubot and its task space. The corresponding simulation to Figure 10 indicates that the work space is so vast that it easily holds the vine entirely and no cut-points are located near or outside of the reachable work space borders, which helps the robot to avoid external singularities. Moreover, the cloud points of end-effector positions are dense in the regions where the cut-points are more likely to exist. Hence, it is demonstrated that Prubot can offer an appropriate workspace for the job. As illustrated in Figure 14, results indicate that in test 1, Prubot is 100% successful in all of the path planning algorithms except in KPIECE and EST, in which success rates are 25% and 75%, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003205_f_version_1666764341-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003205_f_version_1666764341-Figure7-1.png", + "caption": "Figure 7. Top views of typical resulting CADs for the five design goals 1 to 5. The displayed geometries in (a\u2013e) correspond to the listed geometry parameters 1 to 5 in Table 3. The thick red lines show where the Lidar laser scans the ground in front of the vehicle, and the thin red lines show the laser beam path from the Lidar center towards both ends of the thick red lines on the ground.", + "texts": [ + " For Goals 1, 2, and 4, the position of the Lidar was fixed centrally on the vehicle, while for Goals 3 and 5, it could be moved forward and backward. In each of the above design goals, there were still many other geometric degrees of freedom available that led to a multitude of possible geometric setups. Therefore, for each of these design goals, one typical geometric solution was chosen that seemed to achieve the aim without going to unrealistic extremes in any other geometric parameter. The characteristic geometry parameters of each of our chosen CAD solutions are listed in Table 3. A top view of each CAD solution is shown in Figure 7. The CAD variant for Design Goal 1 (Figure 7a) was identical to the prototype vehicle used here. This geometry was used throughout the measurements for this article because it is a good compromise between all the other presented geometries. In general, there are two different strategies for reshaping the FOV of a 2D-Lidar sensor in order to achieve ground detection. This can be seen when comparing Design 1 to Design 2. The first possibility, as in Design 1 (Figure 7a), is to make the laser beam that hits the mirrors at the outward end reflect mostly into the driving direction of the vehicle, i.e., along the y-axis. This results in the right mirror illuminating the near ground at the left side in front of the vehicle and vice versa. The second possibility, as in Design 2 (Figure 7b), is to make the laser beam that hits the mirrors at the inwards end reflect mostly into the driving direction of the vehicle. This results in the right mirror illuminating the near ground at the right side in front of the vehicle and vice versa. When comparing the presented two geometry results, it can be seen that Geometry 1 generated a FOV on the ground that was much nearer to the front of the vehicle (L2 is smaller) and roughly had the width of the vehicle along its full extent in front of the vehicle. In contrast, Geometry 2 created an FOV on the ground with the nearest position further away from the front of the vehicle, but with a width that increased with the distance from the front of the vehicle. The resulting geometry (Figure 7c) for Design Goal 3 proved that it was also possible to keep a large unaffected viewing angle \u03b1 towards the driving direction of the vehicle, in the displayed example of 180\u25e6. For mounting positions of the 2D-Lidar at the very front of a vehicle, as is common for AGVs, this is the maximum useful viewing angle, because towards the back, the vehicle itself normally blocks the Lidar\u2019s view. Therefore, the additional FOV on the ground can in this case be achieved without losing any relevant FOV towards the front. Design Goal 4 was to minimize the total width L1 of the mirror setup. This can be necessary when space for adding plane mirrors next to a Lidar is limited. The corresponding result (Figure 7d) had a total width L1 of around 160 mm. Compared to the width of the current and typical 2D-Lidar sensor housing of around 70 mm, we considered this size increase by a factor of 2 acceptable. In all previous designs presented, the size of the mirrors was kept constant. However, as can be seen in Figure 7, the 100 mm length of the reflecting surface of the mirrors was not fully used in most cases. This was the motivation for decreasing the size of the mirror parts in Design Goal 5. The result is presented in Figure 7e, where the length of the used mirror surfaces was reduced to 43 mm. This significantly reduced the weight of the resulting glass mirror setup. At the same time, it was possible to achieve a very narrow setup with L1 of only 168 mm in the presented example. The calibration procedure presented in Section 2.4 was experimentally tested for several different distances and orientations of the simple flat calibration object. The aim of these experiments was to check if the numeric optimization converged to a realistic result of the mirror orientations" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003743_30457_FULLTEXT02.pdf-Figure4.14-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003743_30457_FULLTEXT02.pdf-Figure4.14-1.png", + "caption": "Figure 4.14: A sample configuration with high stiffness in the global Y direction", + "texts": [ + " 62 | Static Analysis of The Manipulator 63 | Results & Discussion 64 | Static Analysis of The Manipulator As measured by the joint-space evaluation, the highest stiffness in the global X direction occurs when joints 2 and 3 are at 100 and -90 degrees respectively. This configuration is visualized in Figure 4.13. The stiffness in the global Y direction is shaped like a saddle, which conveys the meanings of minimizing the bending moment caused around the base of the robot by having the TCP close to the base. A configuration which is based around this idea is portrayed in Figure 4.14. 65 | Results & Discussion Figure 4.15 visualizes the robot in a stiff Z configuration according to Figure 4.12. The sensible conveyance of this result is to have the mass of the manipulator acting against the direction of the exerted force. 66 | Quasi-Static Analysis of The Manipulator A result of note from the joint-space stiffness evaluation is the weakness of the manipulator in the global Y direction in almost all of the configurations. This is mainly due to the acting bending moment on the base of the robot when the robot is loaded" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003597_f_version_1654854228-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003597_f_version_1654854228-Figure3-1.png", + "caption": "Figure 3. Joint types; (a) \u03b1 = 0, (b) \u03b1 = 1, (c) \u03b1 = 2. Figure 3. Joint types; (a) \u03b1 = 0, (b) \u03b1 = 1, (c) 2.", + "texts": [ + " The maximum length is less important, since the fitness function is trying to minimize the length of the whole manipulator. For our experiments we have used 1000 which was more than enough for the used workspaces. an = 300\u2212 n \u00b7 25 [mm] (1) where: n is the link number and an is the length of the nth link. The joint type describes the rotation of a joint relative to the previous joint, or in the case of the first joint relative to the world coordinate frame. We have used three different orientations shown in Figure 3. The transformation matrices for these joint types are defined in Equation (2). Appl. Sci. 2022, 12, 5897 5 of 14 \u03b1i = 0 \u2192 Ti = cos(\u03b8i) \u2212 sin(\u03b8i) 0 0 sin(\u03b8i) cos(\u03b8i) 0 0 0 0 1 0 ai 0 0 1 \u03b1i = 1 \u2192 Ti = cos(\u03b8i) \u2212 sin(\u03b8i) 0 0 0 0 \u22121 0 sin(\u03b8i) cos(\u03b8i) 0 0 ai 0 0 1 \u03b1i = 2 \u2192 Ti = 0 \u2212sin (\u03b8i) cos(\u03b8i) 0 0 cos(\u03b8i) sin(\u03b8i) 0 \u22121 0 0 0 ai 0 0 1 (2) Appl. Sci. 2022, 12, 5897 4 of 13 2.1. Kinematic Synthesis through Optimization The optimization took place as the second function block in our KBE system", + " The maximum length is less important, since the fitness function is trying to minimize the length of the whole manipulator. For our experiments we have used 1000 which was more than enough for the used workspaces. \ud835\udc4e = 300 \u2212 \ud835\udc5b \u22c5 25 mm (1) where: n is the link number and an is the length of the nth link. The joint type describes the rotation of a joint relative to the previous joint, or in the case of the first joint relative to the world coordinate frame. We have used three different orientations shown in Figure 3. The transformation matrices for these joint types are defined in Equation (2). Transformation matrices for an example 3 DOF kinematic structure with the genotype [300, 0, 400, 0, 200, 1] are shown in (3). TE = cos(\u03b81) \u2212 sin(\u03b81) 0 0 sin(\u03b81) cos(\u03b81) 0 0 0 0 1 0 0.3 0 0 1 \u00b7 cos(\u03b82) \u2212 sin(\u03b82) 0 0 sin(\u03b82) cos(\u03b82) 0 0 0 0 1 0 0.4 0 0 1 \u00b7 cos(\u03b83) \u2212 sin(\u03b83) 0 0 0 0 \u22121 0 sin(\u03b83) cos(\u03b83) 0 0 0.2 0 0 1 (3) where TE is the transformation matrix from the base coordinate frame to the end effector coordinate frame and [\u03b81, \u03b82, \u03b83] is the current joint configuration" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-8-1.png", + "caption": "Figure 8-8. Elastically Conjugate Points", + "texts": [ + ", a sprung vehicle, is determined by the combined elastic and inertial behavior of the particular system. The general procedure for determining the location of the lateral axis of oscillation can be explicated by considering the elastic and the inertial influences separately, and then the combined effect. Figure 8-5 is a diagrammatic representation of a typical vehicular suspension system. The analysis will be simplified if the multiple spring system is replaced by an elastically equivalent two spring system. The two spring system is shown in the upper part of Figure 8-8 and is generated by considering the spring rate moments about the spring center C of the lower system. 8-20 ELASTIC SYSTEM Points such as A and B are called elastically conjugate points. These points are related such that if a vertical force is applied at point A, the body (represented by horizontal axis Y-Y) will rotate about the point B and vice versa. Any pair of points that possess this reciprocal relationship satisfy the equation pq = ab where a, b, p, and q are distances shown in Figure 8-8. Since the dimension q (or p) can be chosen arbitrarily, it follows that there is an infinite number of such pairs of points. The geometrical construction shown in Figure 8-8 enables the pairs of points to be determined graphically. The hyperbola pq = ab \u2014 c2 is drawn relative to the axes XCY. The point \u00dfi corre- sponding to B on the hyperbola is projected horizontally to meet the line CZ at Ai. The projection of Ai on the Y axis give.s the point A. It is obvious that as point A approaches point C, point B will approach infinity. Similarly, as point B approaches point C, point A approaches infinity. 8-21 INERTIAL SYSTEM A similar analysis can be made with respect to dynamically conjugate points" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001304_82703_FULLTEXT01.pdf-Figure4.3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001304_82703_FULLTEXT01.pdf-Figure4.3-1.png", + "caption": "Figure 4.3. Radius recommendation for injected molded parts. [53]", + "texts": [ + " This is also one reason to why it is important to keep the wall thickness consistent, to get an even and fast cooling of the component. The component will be designed with the intent to have no wall thicker than 5mm before drafting. 4.5.3. Corners It is also important to have generously rounded corners to ease the flow of plastic and reduce stress concentrations. A good rule is using at least half of the nominal wall thickness as radius for the inside and using 1.5 times the wall thickness for the outside. This will make the thickness of the corner constant. This is illustrated in Figure 4.3. [53] 4.5.4. Ribs When designing ribs of a structure the ribs should have a thickness of maximum 40-60% of the wall thickness. If the rib is thicker sink marks can appear. It is also important to have a radius of at least 25% of the rib thickness to avoid stress concentrations in the junction. Greater radius reduces the stress concentration more and one can be generous when deciding on radius size. This is illustrated in Figure 4.4. [53] 4.6. CAE Modeling The modeling process consists of modifying the given CAD-geometry, creating a mesh, applying the boundary conditions and then solving the problem" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004943_9668973_09741783.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004943_9668973_09741783.pdf-Figure2-1.png", + "caption": "FIGURE 2. Frames and point of reference in the robot system.", + "texts": [ + " The provided sensors are Quadrature hall effect encoder and Inertial Measurement Unit (IMU) used to measure the corresponding position and orientation of the ADDMR; a LiDAR is also provided for measurements of distance around the robot. The wheels are centered and with center of mass is halfway in between. In addition, two castor wheels are attached for the balance of the ADDMR. B. SYSTEM MODELLING The ADDMR is a type of mobile robots that the speed differences for two actuated wheels cause forward, backward, or turning movement. The illustration can be seen in the following Fig. 2. To establish geometric relationship of the ADDMR, an inertial frame {I } and a body frame {B} are given. Frame reference {I } is attached to the floor and the origin of body frame {B} is located on the center of mass of itself as described in Fig. 2. The orientation of the robot is \u03b8 with respect to the inertial framewhich is calculated by taking angle measurement between the longitudinal axes of body frame and inertial frame. The linear and angular velocities of the ADDMR are calculated with respect to the point o, 33714 VOLUME 10, 2022 i.e. the origin of body frame. Assume that there is a point of contact between each wheel and the floor, there exists resulting tangential velocities from their angular velocities (\u03c6\u0307r , \u03c6\u0307l). The angular and linear velocities of the wheels are proportional to the ratio of the wheel radius R", + " Hence, the ADDMR\u2019s velocities with respect to the inertial frame can be obtained from its wheel angular rates [44]\u2013[48] asI x\u0307BI y\u0307B \u03b8\u0307 = R 2 cos \u03b8 cos \u03b8 sin \u03b8 sin \u03b8 1 L \u2212 1 L [\u03d5\u0307r \u03d5\u0307l ] (1) where \u03b8 is the orientation of the ADDMR. Moreover, the relationship between the velocity of mass (Bx\u0307, \u03b8\u0307 ) with respect to body frame and wheels\u2019 angular velocities are given by:[ \u03d5\u0307r \u03d5\u0307l ] = 1 R [ 1 L 1 \u2212L ] [Bx\u0307 \u03b8\u0307 ] (2) In addition to the kinematic model of Eqs. (1) and (2), the Newton-Euler approach is used to build up the dynamic model of the robot. The ADDMR is assumed to have a unified rigid body and the equations of motion are determined with respect to reference {B} as shown in Fig. 2. Moreover, two motors provide the ADDMR with longitudinal wheel forces (Flwx ,Frwx) created by their corresponding torques (\u03c4l, \u03c4r ) [45], [46], [49]. Hence, the linear and angular accelerations of the robot with respect to the body frame can be represented as Bx\u0308 = 1 MR (\u03c4l + \u03c4r ) (3) \u03b8\u0308 = L JR (\u03c4r \u2212 \u03c4l) (4) That means that the dynamicmodel of the ADDMRgenerates linear velocity (Bx\u0307) and angular velocity (\u03b8\u0307 ) after integration when motor torques \u03c4r and \u03c4l are applied. Combining the aforementioned kinematic with dynamic models, the actuator model is derived to complete the system\u2019s equations of motion" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001083_SET-IJSRMS-09265.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001083_SET-IJSRMS-09265.pdf-Figure5-1.png", + "caption": "Figure 5. Locked Cylinders", + "texts": [ + " To sustain real world situations, the Preserved Geometry is provided along with load magnitude of 800 Newton\u2019s (nearly 80 Kilograms) to the Bottom Cylinder as shown in Figure 4. The arrow indicated with blue signifies that the load has been applied from the upward direction. Green and Yellow color denote the integration of preserved geometry and the optimized shape. It also serves the purpose of an experimental testing of the conditions it can withstand. Load distribution is also done in such a way that the movement is accelerated. To facilitate Locomotion, the central as well as the bottom cylinders are selected as the structural constraints as shown in Figure 5. These are fixed to the leg. The lock signifies the fixing of the following part. It locks the following sub part to the other part of the components such that it is permanently attached and the movement is restricted. The cylinders resemble a hollow wheel like structure permanently affixed with the sub parts generated. The designs have been selected primarily to minimize mass and such that it fulfils the pressure criterion of n times the magnitude applied to any of its part, (in this case) it is 1600 Newton\u2019s on calculating (twice the given magnitude)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000732_-hull-4orosl26hh.pdf-Figure18-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000732_-hull-4orosl26hh.pdf-Figure18-1.png", + "caption": "Figure 18. Rendering of a three-segment MSMR.", + "texts": [ + " The linkage did not provide a roll DoF, resulting in the loss of wheel contact if an obstacle or angular transition was not traversed orthogonally to vehicle motion. Often, when wheel contact was lost the robot would fall from the surface being climbed. A second prototype was built implementing the lessons learned through experimentation with the RC prototype. This second design incorporates the roll-yaw-bow linkage and houses the full electronic suite described earlier. It is being used in the development of the coordinated control software. A three-segment computer-controlled prototype is planned, and an image of the CAD model is provided in Figure 18. It is expected to be more mobile than the two-segment system, but will require a full implementation of the coordinated control system. The prototype MSMR systems developed at SSC Pacific have demonstrated that a multi-segmented magnetic robot with two DoFs between modules can effectively climb and negotiate ferrous surfaces with discontinuities, obstacles, and internal and external corners. Coordinated control of the modules is being developed to enhance operator control of the system. Additional development and maturation is required before the system is ready for testing in operational scenarios" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004999_197h44r_fulltext.pdf-Figure1.2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004999_197h44r_fulltext.pdf-Figure1.2-1.png", + "caption": "Figure 1.2: Overview of wing excursions during WAIR and proposed transitions accompanying the WAIR origin of flight hypothesis. (A and B) Birds running over level substrates or shallow inclines do notrecruit their wings to assist running. However, even partial wing development provides assistanceto individuals during incline (45\u00b0) locomotor performance (C). (C and D) A portion of thewingbeat cycle (up to 30%) involves aerodynamic or inertial forces directed toward the inclinedsurface, rather than skyward, which is sufficient to augment hindlimb traction during WAIR. (D to F) On mastering vertical inclines, birds attain a transverse (dorsoventral) wing excursion that isrequired for aerial flight.[14]", + "texts": [], + "surrounding_texts": [ + "Bio-inspiration and bio-mimicry offer great promise to the design, development, and capabilities of mobile robots. Animals have evolved to be able to traverse across expansive types of environments in nature, with some animals displaying impressive multi-modal capabilities. Researchers have tried to emulate such multi-modal capabilities with the concept of hybrid locomotion mobile robotic systems starting in the early 1980s [25]. What followed was research combining different environmental locomotion capabilities like aerial-wheel [37] and aquatic-wheeled [58]. Some others include ASGUARD- a leg-wheeled platform [3], SCAMP- an aerial-climbing platform [42], and HyTAQ - an aerial-terrestrial platform [28]. ANYmal on Wheels is an enhanced iteration of the ANYmal robot, featuring wheels located at the end of its legs[51], while Max[10], a research platform created by Tencent, is equipped with wheels positioned at the knee joint. A fascination of researchers has long been the locomotive capabilities of birds. Birds are agile flyers; they can walk rapidly, jump over large obstacles and fly to evade predators. This type of mobility is of high interest in robotic applications for scenarios where only one type of locomotion would be insufficient such as search and rescue missions. Aerial and legged locomotion offers the possibility of long-distance travel with a flight mechanism, while the walking mechanism helps in close inspection and surveillance in terrain where wheeled robots would face difficulty. Research on combining aerial and ground mobility capabilities in a single robot is still in its early stages. In the initial stages, wings were utilized for achieving aerial capabilities with Morphing Micro Air-Land Vehicle (MMALV) [4] being one of the first. Further, such implementations were explored with DALER [11] with a foldable skeleton mechanism used for both wing and flight. In these designs, efforts to integrate legged and aerial mobility mechanisms in a single platform are often constrained by the divergent design considerations 1 CHAPTER 1. INTRODUCTION for each system. As such, it can be challenging to fully incorporate the functionalities of both legged and aerial systems in a unified platform. Husky Carbon, which is our project inspired by the locomotion of birds, has shown the possibility of integrating quadrupedal-aerial locomotion[46] into a single platform. This integration is motivated by the need for fast mobility at high altitudes and safe, agile, and efficient mobility in unstructured spaces. In certain scenarios, mono-modal mobile systems may easily fail, posing challenges in Search and Rescue (SAR) operations and the aftermath of disasters. For example, Unmanned Aerial Systems (UAS) can perform aerial surveys and reconnaissance, but airborne structural inspection of buildings and mobility inside collapsed structures is challenging. On the other hand, legged mobility is superior in these scenarios. The energy efficiency of legged locomotion is much higher and as a result operation endurance when legged locomotion is utilized is much higher than flight endurance. 2 CHAPTER 1. INTRODUCTION 3 CHAPTER 1. INTRODUCTION" + ] + }, + { + "image_filename": "designv7_3_0002047_6514899_10220077.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002047_6514899_10220077.pdf-Figure4-1.png", + "caption": "FIGURE 4. (a) DC motor steering hardware (b) DC motor steering design outline", + "texts": [ + " & Ganesan Kaliyaperumal.: Hardware and Software Design for Mobile Robot\u2019s Navigation over On-road and Off-road Curvature Paths directions) can detect a rotation every 1.5 feet, allowing one to calculate the speed of the Mobile Robot. The Mobile Robot's MPU9250 IMU sensor provides information on its direction of movement. An accelerometer, gyroscope, and magnetometer are included in the sensor. The magnetometer has three axes: roll, yaw, and pitch. The Mobile Robot's direction is determined by its yaw value. Figure 4 depicts the actual mobile robot steering hardware. Figure 4 (b) clearly shows how the front DC motor controls the center steering shaft. The DC motor steering mechanism has been modified as a Linear Actuator controlled steering mechanism for travelling over curved paths, over uneven offroad, over tiny obstacles, and so on, as illustrated in Figure 5. In this redesign, a Linear Actuator is used and can hold the center steering shaft with a maximum load capacity of 110 N. The beginning point of the actuator rod has become entangled with the center portion of the center steering shaft (see Figure 5 (b))" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001973_f_version_1615790400-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001973_f_version_1615790400-Figure6-1.png", + "caption": "Figure 6. An illustration of the test workpieces used in our experiments. Each of them is part of the ABC Dataset [22], except for the custom workpiece number 9.", + "texts": [ + " Therefore, a correlation between the policy objective LCLIP(\u03b8) and a value error term c1LVF t (\u03b8) is considered in (12) besides the exploration error term c2S[\u03c0\u03b8 ](st), which checks if the exploration frequency is high enough. The link of the PPO architecture with policy and value networks, operating as actor and critic, to the task environment of the presented framework is visualized in Figure 5. This section presents various experiments with the newly introduced learning framework for view pose planning to provide a proof of concept. Figure 6 shows the exemplary integrated test workpieces from the open-source ABC dataset [22], which collects about one million models in total, as well as a custom test workpiece. The workpieces were scaled such that they are approximately the same size. We present experimental results for the three RL algorithms introduced in Section 2.3.3. Table 1a displays the training settings for Q-learning, Table 1b for DQN and Table 1c for PPO. The experiments have been executed on a PC with 32 GB RAM, an Intel Xeon W-2125 processing unit with 8 cores and 4 GHz clock rate, and a Nvidia Quadro P2000 GPU with 32 GB" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.41-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.41-1.png", + "caption": "FIGURE 21.41. Discretization of the surface of a car to compute the aerodynamic field using the panels method (a) and of the whole aerodynamic field using the finite element approach (b).", + "texts": [ + " This difference is linked with the difficulty of predicting numerically where the flow detaches from the body: computational aerodynamics yields very good results in case of attached flows, but when large wakes or separation bubbles are present the computation becomes more difficult and the results less reliable. Numerical methods may, on the contrary, be used without problems in automotive aerodynamics if the location where the flow detaches is known. Numerical aerodynamics is based mainly on the discretization of the aerodynamic field, and on the use of a simplified form of the Navier-Stokes equations. The simplest approach is the use of the boundary elements method, which in aerodynamics is often referred to as the panels method. Only the surface of the body needs to be discretized (Fig. 21.41a). This is a linearized method, and can be used on an attached inviscid flow, although it may be applied also to zones where the separation zone is known and described geometrically with high precision. It is a technique widely used in aeronautics, but in the automotive case it requires the use of experimental techniques to define the zones where the flow separates. The methods based on the discretization of the whole aerodynamic field up to a certain distance from the vehicle (finite differences method, finite elements method (FEM, Fig. 21.41b)) allow nonlinear forms of the Navier-Stokes equations to be discretized as well, and the zone where the flow detaches to be computed through iterative techniques. Combined approaches are also possible, to combine the advantages of the various methods. An example of the computation of the pressure distribution, accurately obtained using the finite volumes methods, is shown in Fig. 21.4217. To obtain such a good result, the aerodynamic field was subdivided into more than 5 million cells. 17H. Wustenberg, B" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004883_f_version_1635910427-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004883_f_version_1635910427-Figure13-1.png", + "caption": "Figure 13. Structure of the new end-effector for a citrus picking robot meeting the demands of the spherical fruit and clamp damage reduction: 1, tube; 2, swing knife; 3, motor; 4, spherical finger; 5, motor; 6, airbag.", + "texts": [ + " In addition, a horizontal rotation degree of freedom was added between the base of the 2-DOF manipulator and the lifting platform to meet the demands of a flexible attitude change during picking. 4.4.3. End-Effector According to the demands of picking citrus with a flat stem and reduced clamp damage, the technologies required for citrus clamping mainly include double spherical finger structures (CN213214398-U), airbag grasping (CN111937592-A), and pipeline swallowing structures (CN111972127A). From this technical combination, a robot end-effector for picking fruit with a flat stem was created. Its structure is shown in Figure 13. The new end-effector is composed of two spherical finger mechanisms, a knife swing mechanism, a pipeline airbag sucker structure, and a fruit delivery hose. \u2022 The two spherical finger mechanisms are composed of a relatively symmetrical 1/4 spherical holding finger and a single-motor symmetrical transmission mechanism. Processes 2021, 9, 1905 17 of 21 The two spherical fingers are symmetrically installed above the tube and driven to open and close by the motor in order to clamp the fruit; \u2022 The knife swinging mechanism is a semicircular narrow knife, which is also installed above the tube, and swung upward and reset by the motor" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000377_9359896_09311188.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000377_9359896_09311188.pdf-Figure7-1.png", + "caption": "Fig. 7. Schematic representation of the pendulum with respect to the knee joint.", + "texts": [ + " A trigonometric function gives the moment arm: r(\u03b8p) = \u221a h2 knee + d2 knee sin ( tan\u22121 ( dknee hknee ) + 20\u03c0/180 \u2212 \u03b8p 2 ) In which the moment arm is calculated from the configuration parameters, hknee and dknee (as shown in Figure 2) in m and the pendulum angle \u03b8p in rad. This is derived from a straightforward trigonometric analysis of the knee joint. Note the 20\u25e6 offset between pendulum angle, \u03b8p, and knee angle (\u03b8knee = 20 \u2212 \u03b8p), that matches the pendulum orientation with that of a leg in swing. This is shown in Figure 7. The moment arm is also multiplied by the output force to find the torque acting on the pendulum, so this geometric nonlinearity is introduced twice in the system; from PREHydrA to pendulum block and back. Let\u2019s assume a constant moment arm. Figures 8 and 9 show the transfer functions of the control plants for the output force and pendulum angle controlled systems respectively, calculated for different values across the entire range of possible moment arms. Figure 8 shows that the changing moment arm does not influence the location of the anti-resonance at 0" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000201_f_version_1669012486-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000201_f_version_1669012486-Figure2-1.png", + "caption": "Figure 2. Structure of PAM.", + "texts": [ + " Therefore, we developed a smart PAM system that estimates the amount of contraction of a PAM based on the amount of circumferential deformation by means of a flexible flexure sensor based on strain gauges attached to the surface of the PAM. Its self-monitoring function enables detection of any excessive contraction and deterioration. This paper proposes a smart PAM system that resembles human muscle through use of muscle spindles, and introduces its structure, manufacturing method and sensing technique to explain its effectiveness. Figure 1 portrays a photograph of the PAM in its actuated condition. Table 1 shows the specifications of the PAM used for this study. In addition, Figure 2 portrays the structures of a McKibben-type PAM and a PAM reinforced by straight fibers, the latter of which was the PAM type used in this study. For manufacture of the PAM, the groove of the silicon tube, extruded into a gear type as shown in the figure, was a bonded carbon fiber strip, further covering the thin-film silicon tube of the cylinder on the outer periphery. In addition, the configuration of the pneumatic joint section for the actuator, as shown in the figure, consisted of a male threaded portion, a female threaded portion and a tapered portion", + " Therefore, we developed a smart PAM system that estimates the amount of contraction of a PAM based on the amount of circumferential deformation by means of a flexible flexure sensor based on strain gauges attached to the surface of the PAM. Its self-monitoring function enables detection of any excessive contraction and deterioration. This paper proposes a smart PAM system that resembles human muscle through use of muscle spindles, and introduces its structure, manufacturing method and sensing technique to explain its effectiveness. Figure 1 portrays a photograph of the PAM in its actuated condition. Table 1 shows the specifications of the PAM used for this study. In addition, Figure 2 portrays the structures of a McKibben-type PAM and a PAM reinforced by straight fibers, the latter of which was the PAM type used in this study. For manufacture of the PAM, the groove of the silicon tube, extruded into a gear type as shown in the figure, was a bonded carbon fiber strip, further covering the thin-film silicon tube of the cylinder on the outer periphery. In addition, the configuration of the pneumatic joint section for the actuator, as shown in the figure, consisted of a male threaded portion, a female threaded portion and a tapered portion", + " Air pressure input to the PAM was controlled by an electro-pneumatic proportional valve (ETR-200-1; Koganei Seisakusho, Tokyo, Japan). Accuracy of the linear potentiometer used demonstrated a \u00b1100 mm rated capacity and nonlinearity within \u00b10.5%; 100 mm \u00d7 0.5% = \u00b10.5 mm. Figure 4 shows the characteristics of the relationship between input pressure and the amount of contraction. Our PAM had a dead zone between 0 MPa and 0.08 MPa, contracted significantly at 0.08~0.12 MPa and increased slowly afterward. Sensors 2022, 22, x FOR PEER REVIEW 4 of 11 Figure 2. Structure of PAM. 2.2. Fundamental Characteristics Figure 3 shows the experimental setup for measuring the relationship between input pressure and contraction. In this experiment, the input air pressure was set from 0 MPa to 0.18 MPa, in 0.02 MPa increments. One end of the PAM was connected to a fixed plate. The other end was connected to a slider that moved freely in the horizontal direction. The PAM was therefore driven along the slider. The PAM was then extended and retracted by the sliding jig, and the amount of expansion and contraction of the acrylic plate connected to this jig (equal to the amount of expansion and contraction of the PAM) was measured with a linear potentiometer (DLT-100AS: KYOWA ELECTRONIC INSTRUMENTS CO", + " Air pressure input to the PAM was controlled by an electro-pneumatic proportional valve (ETR-200-1; Koganei Seisakusho, Tokyo, Japan). Accuracy of the linear potentiometer used demonstrated a \u00b1100 mm rated capacity and nonlinearity within \u00b10.5%; 100 mm \u00d7 0.5% = \u00b10.5 mm. Figure 4 shows the characteristics of the relationship between input pressure and the amount of contraction. Our PAM had a dead zone between 0 MPa and 0.08 MPa, contracted significantly at 0.08~0.12 MPa and increased slowly afterward. Sensors 2022, 22, x FOR PEER REVIEW 4 of 11 Figure 2. Structure of PAM. Figure 3 shows the experimental setup for measuring the relationship between input pressure and contraction. In this experiment, the input air pressure was set from 0 MPa to 0.18 MPa, in 0.02 MPa increments. One end of the PAM was connected to a fixed plate. The other end was connected to a slider that moved freely in the horizontal direction. The PAM was therefore driven along the slider. The PAM was then extended and retracted by the sliding jig, and the amount of expansion and contraction of the acrylic plate connected to this jig (equal to the amount of expansion and contraction of the PAM) was measured with a linear potentio eter (DLT-100AS: KYOWA ELECTRONIC INSTRUMENTS CO" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000032_f_version_1613481839-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000032_f_version_1613481839-Figure6-1.png", + "caption": "Figure 6. Variation of the manipulator design with two circular guides that permits higher values of rotational angle \u03d5.", + "texts": [ + " The extreme values of angle \u03d5 are smaller than the ones for the classical GoughStewart platform that can reach about 60\u25e6 [36,37]. However, with Equations (23)\u2013(26), one can formulate an optimization problem to find mechanism geometry that will maximize the range of rotation. Another solution is to change the manipulator structure and use two circular guides: one of them is inside the other (as in [38]) or stacked over it. Each guide will support only three carriages increasing their driving range and, therefore, the rotational capabilities of the platform. Figure 6 presents such a variation of the proposed design with two circular guides. The swinging arms can rotate at higher angles leading to the increased value of platform rotational angle \u03d5. Here are: 1\u2014inner circular guide (fixed link); 2\u2014outer circular guide (fixed link); 3\u2014drive; 4\u2014support for drive 3; 5\u2014crank; 6\u2014slide block; 7\u2014swinging arm; 8\u2014carriage; 9\u2014leg; 10\u2014platform (end-effector). The proposed design requires location of the centers of spherical joints 9\u201310 according to view I in Figure 6, where each pair of these joints is on the same radius of the platform. To provide higher rotational angle \u03d5, three kinematic chains of links 5\u20137 are moved under the circular guides (section A-A in Figure 6). For the presented design, the maximum value of rotational angle \u03d5 is about 55\u25e6, which is comparable to the Gough-Stewart platform. Both proposed designs in Figures 1 and 6 can be further optimized to enhance the rotational capabilities of the platform, not only in one particular configuration but over the whole working area. This topic is beyond the current study but presents interest for future research. This study has presented a novel version of the 6-DoF manipulator with a circular guide. The proposed manipulator has such design advantages as having all drives fixed on the base, sufficiently large rotation of the end-effector around the vertical axis, and using cranks as the driving links (as an alternative to carriages) placed within the circular guide" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001597_ae-iot2018_03046.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001597_ae-iot2018_03046.pdf-Figure2-1.png", + "caption": "Figure 2. The first-order mode shape when four sides are fixed.", + "texts": [ + " Generally, the modal effective mass of the high-order mode accounts for a very small proportion, so only the low-order mode is concerned. As to the calculation of the restraint modes of the motor base, the low-order modes are calculated. The natural frequencies with different boundary constraints are shown in Table 1 Table 1 shows that the natural frequencies are close when two wide sides and four sides are fixed. The natural frequencies are slightly smaller when two narrow sides are fixed. Due to length of space, parts of mode shapes are shown in Figure 2-4. Although the boundary constraints are different, the mode shapes are basically similar except that the vibration amplitude is slightly different. The mode shape of the first-order vibrates back and forth. The mode shape of the second-order vibrates left and right, and the third-order occurs torsion. The vibration amplitude of high-order mode shapes is larger. The maximum speed of the motor is 6000 rpm which corresponds to 100 Hz of the natural frequency. Resonance will happen when the frequency is lower than 100 Hz", + " The natural frequencies with different boundary constraints are shown in Table 2. Table 2 shows that the natural frequencies of the improved motor base are much higher than which of predesign motor base. Also, the natural frequencies are still close when two wide sides and four sides are all fixed. But the difference between the two constraints is more obvious. The natural frequencies of the improved motor base under the situation that two narrow sides are fixed, are significantly smaller than others boundary constraints. The mode shapes are similar to Figure 2-4, as shown in Figure 6-8. The mode shape of the first-order vibrates back and forth. The mode shape of the second-order vibrates left and right, and the mode shape of the third-order occurs torsional phenomenon. Although the first-order frequency of 110.6 Hz under the situation that two wide sides are fixed is more than 100 Hz, it is too close. The first-order frequency of 125.53 Hz under the situation that four sides are all fixed is much more than 100 Hz, so the situation is chosen as installation method which can better prevent resonance" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003027_8600701_08876854.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003027_8600701_08876854.pdf-Figure3-1.png", + "caption": "FIGURE 3. Rotation of single wheel. We use it as a simplified model to analyze the kinetics analysis of robot.", + "texts": [ + " KINETIC ANALYSIS According to the existing studies [25], [26], it is an effective way to explain the rationality of the design by analyzing the dynamics and kinematics of the model. So, in order to verify the superiority of the steering method proposed in this paper, this segment describes the force of the parallelogram linkage under different motion conditions due to the motion coupling of four wheels. Assume that each wheel keeps balance on the ground and does pure rolling motion without skidding, and the friction of the bearing on the vertical rotation axis is omitted. For convenience, as shown in Fig. 3, the rotation of one wheel 152140 VOLUME 7, 2019 around the vertical rotation axis is extracted from the overall motion. The momentum moment of the wheel around the vertical rotation axis is: Lz = Jz\u03c9z (1) where, Jz is the wheel\u2019s moment of inertia around vertical rotation axis,\u03c9z is the angular velocity of particles on vertical rotation axis due to the turning of wheels. To the best of our knowledge, the expression for the torque Mz can be given below: d dt Lz = Mz (2) By calculating the first derivative of (1) and combined with (2), the following equation can be obtained: Mz = Jz d\u03c9z dt (3) We use Mi to express the torque exerts on different vertical rotation axis and it can be proposed as follows (i = 1,2,3,4", + " And we use \u03b8 = \u03b8t \u2212 \u03b8t\u22121 to represent it (Let\u2019s stipulate that the motion starts at time zero), \u03b8t\u22121 represents the initial angle of wheel at the start of each motion, \u03b8t represents the angle value at time t. L is the arc length corresponding to \u03b8 . For convenience, it is assumed that the initial steering angle of the wheel is \u03b8t\u22121 = 0. And the relevant analysis is conducted on the assumption that wheel does not slipping, so the path S that the wheel rolls over can be calculated as: S = r\u2217\u03d5 (10) S = L (11) where \u03d5 is the rotation angle of the wheel around the x-axis direction, as presented in Fig. 3. At which the wheel rolls purely along the ground and the angle is reflected by the motor. r is the radius of wheel. Through the derivation of the (9), (10) and (11), the following equation can be obtained: \u03d5 = b r \u03b8 (12) By calculating the first derivative of the (12), the expression for the angular velocity of the wheel as it rolls purely along the ground \u03c9c can be presented as below: \u03c9c = b r d\u03b8 dt (13) In consideration of the robot\u2019s motion just in two-dimensional space, the two-dimensional coordinate systems are set up as shown in Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001853_d.aspx_paperID_80070-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001853_d.aspx_paperID_80070-Figure1-1.png", + "caption": "Figure 1. Type-2 fuzzy logic membership function.", + "texts": [ + " The dynamics of the electrical robot (1)-(4) in the state space is formed as ( )= +f bux x (5) where ( ) ( ) ( ) ( )( ) ( ) ( ) 2 1 1 1 1 1 2 2 3 4 1 2 1 3 4 5 1 4 5 , m b \u2212 \u2212 \u2212 \u2212 \u2212 \u2212 + = \u2212 \u2212 + \u2212 + g f J x D x x Kx C x x x Krx xx rKx r Kx Bx K x L K x Rx , 1\u2212 = b 0 0 0 0 L , m m a = I x \u03b8 \u03b8 \u03b8 \u03b8 A fuzzy logic system that uses at least one type-2 fuzzy set is called a type-2 fuzzy logic system. It is very useful in circumstances where determination of an exact membership grade for a fuzzy set is difficult [4]. As illustrated in Figure 1, a DOI: 10.4236/jsea.2017.1011048 858 Journal of Software Engineering and Applications type-2 fuzzy membership function (MF) can be obtained by starting with a type-1 MF and blurring it. The extra mathematical dimension provided by the blurred area, referred to as the footprint of uncertainty (FOU), and represents the uncertainties in the shape and position of the type-1 fuzzy set. The FOU is bounded by upper and lower MF, and points within the \u201cblurred area\u201d have membership grades given by type-1 MF" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.15-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.15-1.png", + "caption": "Figure 4.15 Overview & Dimension of Rack Axle (cm)", + "texts": [ + "5 Overview & Dimension of the Frame 1 (P57) Figure 4.6 Overview & Dimension of the Frame 2 (P58) Figure 4.7 Overview & Dimension of the Wheel (P58) Figure 4.8 Scissor Lift Supporting Operator Cabin (P59) Figure 4.9 Hydraulic Pump (P59) Figure 4.10 Front View of Scissor Lift with Maximum Lifting Range (P60) Figure 4.11 Collapsed View of Lifting Fork Assembly (P61) Figure 4.12 Exploded View of lifting Fork Assembly (P62) Figure 4.13 Overview & Dimension of Fork Lid (P63) Figure 4.14 Overview & Dimension of Fork Support Frame (P64) Figure 4.15 Overview & Dimension of Rack Axle (P65) Figure 4.16 Overview & Dimension of Rack Fixer (P65) Figure 4.17 Overview & Dimension of the Fork (P66) Figure 4.18 Overview & Dimension of Spur Gear (P67) Figure 4.19 Overview & Dimension of Rack Motor (P67) Figure 4.20 Fork Horizontal Movement of the Forks (P68) Figure 4.21 Vertical Movement of the Forks (P69) Figure 4.22 Rotation of the Forks (P69) Figure 4.23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004944_56597_FULLTEXT01.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004944_56597_FULLTEXT01.pdf-Figure3-1.png", + "caption": "Figure 3: Basic solution scale abele in length. Perspective view.", + "texts": [ + " As already in the design, all solutions must be recyclable. It should be easy to carry parts on existing transport solutions. All components must be removable by hand. The construction should provide protection for the climate and offer security and dignity for the people living or working there. It should be resistant to violence caused by hand. The solution should provide conditions to gradually enhance comfort and sanitation solutions in place. A basic model scalable in length with floors, walls, and ceilings (Figure 3 and 4) could be used in an emergency effort to later be supplemented with additional storeys and with a more permanent foundation. This means that the first part would be mounted on the latter. The basic model consists of three different building elements for walls and ceilings. The floor also consists of three different elements. This idea is realized in a project that will create a guideline of how effective flows with automated production for similar products can be created. Identified needs and requirements, as well as the project structure, are summarized in Figure 5" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003734_6514899_10316279.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003734_6514899_10316279.pdf-Figure4-1.png", + "caption": "FIGURE 4. 3T&3R metamorphic parallel robot in 3T motion mode.", + "texts": [ + " It should be noted that we do not consider the case of elements oij = \ud835\udf0b (ij = 12,13,23) in the MCM D1, because oij = \ud835\udf0b indicates that the metamorphic parallel robot is in singular configuration, and the singularities of mechanisms are generally not considered during the type synthesis process. The physical model of 3T&3R metamorphic parallel robot is made by 3D printing technology, as shown in Figs. 4 and 5. When the revolute pair R1 in each branch chain is locked, the moving platform of the 3T&3R metamorphic parallel robot has three translational DOFs and can move in any direction, as shown in Fig. 4. When the prismatic pair P6 in each branch chain is locked, the moving platform of the 3T&3R metamorphic parallel robot has three rotational DOFs and can rotate along any axis, as shown in Fig. 5. Moreover, the 3T&3R metamorphic parallel robot can switch between 3T and 3R motion modes in any position and posture. Wheels have the characteristics of unrestricted movement range. If wheels can be used in the design of parallel robots, then a class of wheeled parallel robots with large working space can be invented" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003807_icsbook-download.pdf-Figure19-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003807_icsbook-download.pdf-Figure19-1.png", + "caption": "Fig. 19: Parts are presented to the customer (the operator) in stacks on a table.", + "texts": [ + " 10: The exponential curve of progress in robotics technology. 48 Fig. 11: Example of robotic cell delivering value to a customer. 51 Fig. 12: Two cell deployment timelines (...) 56 Fig. 13: Overview of phases in the lean robotics cell deployment sequence. 59 Fig. 14: Design phase overview. 69 Fig. 15: Example of a simplified value stream map. 70 Fig. 16: Manual task map and layout steps shown in overall design phase sequence. 74 Fig. 17: Template for manual task map summary. 83 Fig. 18 : Example of a finished part. 86 Fig. 19: Parts are presented to the customer (the operator) in stacks on a table. 86 Fig. 20: Input part (blank). 87 Fig. 21: Blank parts are presented to the operator in stacks on a table. 88 Fig. 22: Sequence of manual process. 90 Fig. 23: Acme\u2019s manual task map summary. 93 Fig. 24: Acme\u2019s drawing of the manual cell layout. 94 Fig. 25: Acme\u2019s illustration of their manual station. 95 Fig. 26: Robotic cell concept, layout, and task map steps shown in overall design phase sequence. 98 Fig. 27: Robotic task map template", + " Let\u2019s start by looking at their initial process for creating their manual task map. The cell customer is the operator who brings the machined parts to an inspection station. \u2192 a tray of 60 parts every 2 hours (specifically part numbers AGS202, AGS204, AGS225, AGS400), so I can... \u2192 take the finished parts to the inspection station (see Fig. 18). 86 DEPLOYING YOUR ROBOTIC CELL Fig. 18 19.2 mm 50\u201363.75 mm 70\u2013110.5 mm : Example of a finished part. Par t(s) presentation The following questions relate to how the parts are arranged at output (see Fig. 19). Are the parts singulated? How much space is around them? \u2192 The parts are stacked on top of each other. \u2192 The stacks of parts are on a tray. 87 Are the output parts placed onto a moving surface (e.g. a conveyor belt)? \u2192 No, they are placed on a stable surface (a tray on a table). Nature of the par t(s) How many types of parts are there? \u2192 There are four different types of blanks. \u2192 See Fig. 20. \u2192 Max: 110.5 mm x 63.75 mm x 19.2 mm rectangular blocks \u2192 Min: 70 mm x 50 mm x 19.2 mm rectangular blocks \u2192 Max" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004805_4785241_10308529.pdf-Figure21-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004805_4785241_10308529.pdf-Figure21-1.png", + "caption": "Fig. 21. Hooves loaded for yaw stiffness test on the linear guide setup.", + "texts": [ + "e., 19.75 kg. Therefore, the foot will be safe because of the adaptation of the foot happens at a much lower load. 3) Yaw Stiffness Stability Test (Lower Bound): In the yaw case, observations are made to find the maximum load that opens hoof\u2019s yaw phalange digits to the maximum available deflection based on the obstacle profile. Because if the phalanges adapt to the obstacle shape, they cannot move anymore. Then the foot will see a rigid collision, which is not preferred. It can also be seen in Fig. 21. The values of the loads to achieve the maximum possible deflection are shown in Table VI. A comparison of how the load varies among different surface materials is shown in Fig. 22. 4) Yaw Stiffness Stability Test (Upper Bound): We use the rectangular obstacle R40 as the ground feature in this test. Though the maximum possible vertical translation of the system is 20 mm, a 40 mm obstacle is used to give space for the other hoof to move. The load that opens the hoof pad is 12.5 kg. It is less than the permissible limit of 150 N (\u224815" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000152_d.aspx_paperID_39416-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000152_d.aspx_paperID_39416-Figure9-1.png", + "caption": "Figure 9. Block diagram of the electro-hydraulic system.", + "texts": [ + " Gain/phase margins, phase/gain crossover frequencies, Integral of the Square Error (ISE), and Integral of the Absolute Error (IAE) are given in Table 1. From Table 1 and Figure 8, one can see that the proposed method gives faster response, better performance, and better robustness than those of other methods presented. Note that the proposed mrthod can provide a simple way to improved the system that has been controlled. Example 2: Consider an electro-hydraulic velocity/position servo control system [22] shown in Figure 9. The relation between the servo spool position vX and the input voltage u is in the form of 2 2 2 1 v v v v v X K G s u s s v (12) where vK is the valve gain, v is the damping ratio of the servo valve and v is the natural frequency of the Open Access JAMP T.-S. TSAY Open Access JAMP 89 servo valve. In general, Equation (12) can be approximated by v vX K u for large v . The relation between the valve displacement VX and the load flow rate LQ is governed by the well-known orifice law [22] 7 2 t3" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-7-1.png", + "caption": "Figure 70-7. Vertical Volute Spring Bogie", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\nREFERENCES 1. AMCP 706-355, Engineering Design Handbook,\nAutomotive Series, The Automotive Assembly, Chap. 11. 2. Ibid., p. 11-2. 3. C. H. Winfree, Structural Design Criteria for\nMilitary Vehicles, U.S. Army Tank-Automotive Center, Warren, Mich., Sept. 1962, pp. 20-21. 4. IIIAGSED, Handbook of Instructions for Aircraft Ground Support Equipment Designers,\nJune 1963, Part A. 5. Maintenance Criteria, U.S. Army Tank-Auto-\nmotive Center, Warren, Michigan, January, 1959. 6. W. Steeds, Mechanics of Road Vehicles, Iliffe and Sons Ltd., London, England, 1960, pp. 181- 8. 7. AMCP 706-355, op. cit., Chap. 12. 8. T. Baumeister, Ed., Mark's Mechanical Engi-\nneers' Handbook, 6th Ed. McGraw-Hill Book Co., Inc. N. Y. 1958, p. 11-13. 9. AMCP 706-355, op. cit., Chap. 11. 10. \"Plastic Wheels,\" Machine Design 31, 26-27\n(1959).\n11. S. A. Zdan, Design and Manufacture of 25 X 13.00 Aluminium Wheel for Truck Tractors, XM-376 and XM-377, Kelsey-Hayes Company, Detroit, Mich., 1956. 12. T. Franzen, Development of Light Military Track Wheels Under Technical Supervision of Detroit Arsenal, Kelsey-Hayes Company, Detroit, Mich., 1956. 13. AMCP 706-355, op. cit., p. 11-37. 14. Standard Military Components Directory, U.S.\nArmy Tank-Automotive Center, Research and Development Directorate, Warren, Mich. 15. Handbook of Off-the-Road Tires, The Goodyear Tire and Eubber Company, Akron, Ohio, 1952, pp. 46-7. 16. AMCP 706-355, op. cit., pp. 11-39, 11-40. 17. R. C. Kerr, Motor Vehicle Design Studies,\nArabian American Oil Company, New York, N. Y, 1955, pp. 7-46. 18. K. P. Eklund, The Influence of Load and Inflation on the Selection of Pneumatic Tires for Military Vehicles, Rept. No. 922, U.S. Army Engineering Research and Development Laboratories, Ft. Belvoir, Va., 1945.\n9-46", + "AMCP 706-356\nCHAPTER 10\nSUSPENSIONS FOR TRACKED VEHICLES*\nSECTION I GENERAL 10-1 INTRODUCTION\nThe design goals for suspension systems for tracked vehicles are identical to those applying to the vehicle as a whole. Among these goals are: (a) maximizing mobility, utility, reliability and durability, (b) minimizing fuel consumption, weight, maintenance and cost, and (c) achieving a high level of standardization of components.\nThe purpose and function of the suspension system for tracked vehicles are discussed in Chapter 2. The characteristics, purpose, and functions of the various components and subsystems that are combined to form the total suspension system are discussed in subsequent sections of this chapter. Components within the current suspension systems for tracked vehicles include: (a) track assemblies, (b) road wheels and tires, (c) sprockets, (d) support rollers, (e) road wheel arms or links, (f)' spring systems, (g) damping systems (shock absorbers), (h) bump stops, and (i) track envelope adjusters. A number of standard types of these components are illustrated in Appendix II, showing how these components are integrated into a suspension system for the track-laying vehicles.\nIn addition, a rather extensive tabulation of a representative number of standard suspension systems and their characteristics are also given in Appendix II. These data should provide useful guidance to those designers who are new to the military vehicle design field and should serve as a useful check of past and current design accomplishments to the more experienced military designer.\n10-2 GENERAL TRACKED SUSPENSION TYPES\n\u2022 Written by Nicholas R. Rome of the IIT Research Institute, Chicago, Illinois.\n10-2.1 BOGIE SUSPENSIONS A bogie for a tracked vehicle (tank bogie) is a suspension assembly consisting of a system of links, arms, and springs interconnected in a manner to permit two or more road wheels to function together in tandem. This type of suspension was used extensively on early tracked vehicles but is now obsolete The independent type of suspension is used exclusively on modern American tracked vehicles.\nThe bogie suspension provides a walking-beam effect that divides the load equally between a pair of tandem wheels. When one of the wheels is displaced, or is subjected to a vertical track force, an equal force is reflected on the wheel of the bogie unit. This arrangement permits the vehicle to ne-\n10-1", + "AMCP 706-356\n1. The displacement of one or several road wheels does not substantially change the displacement of the remaining road wheels. 1. The maximum displacement of a single road wheel is greater than the maximum simultaneous displacement of all the road wheels of the entire bogie unit.\n2. Changing the loading of one road wheel does not change the loading of the others while the hull is stationary. Redistribution of the loads on the road wheels is possible only by changing the position of the hull. 2. Changing the loading of one road wheel correspondingly changes the loading of the other wheels of the bogie unit.\n3. In encountering a terrain irregularity, an impact is immediately received by only one road wheel. 3. In encountering a terrain irregularity, the impact is received by all of the road wheels of the particular bogie unit.\n4. Decommission of one road wheel does not impair the effectiveness of the remaining road wheels except for the increased load. 4. Decommission of one road wheel impairs the functioning of the entire bogie unit.\n5. Large diameter road wheels are usually employed; never less than 18 in. 5. Numerous small-diameter road wheels are used, improving weight distribution but reducing tire life.\n6. Mechanically less complex than bogies, thereby facilitating maintenance. More protected from damage by enemy action and terrain debris. 6. More complex than independent; therefore, more subject to malfunction and difficult to maintain. More exposed to ballistic attack.\n7. Usually softer suspension with higher reserve of energy absorption and road wheel deflection, compared with bogies. Dampers essential. 7. Usually harder suspension resulting in harsh jolting ride.\n8. Recommended for high-speed (over 10 mph) operation because of superior impact absorption reserve. 8. Inferior for high-speed operation because of preloading of suspension spring by interconnection of road wheels in tandem. Superior for low-speed locomobility because interconnection equalizes load.\n9. No inherent track tension adjustment to compensate for road wheel deflections. 9. Substantial inherent track tensioning compensation for wheel deflections.\n10. Combined types offer certain functional advantages but not advised because of increased parts inventory requirement.\ngotiate substantial terrain irregularities without transmitting undue shocks to the sprung mass and without varying excessively the load distribution or vehicle elevation. The bogie suspension behaves in the manner intended at low speeds only. For the typical vehicle, at speeds above 10 mph, the walking beam effect is lost and the entire bogie\nunit \"pancakes,\" reducing the remaining spring travel to a small value.\nVarious types of bogie suspension systems are described in Ref. 1. Schematics of bogie suspension units are shown in Figures 10-1 and 10-2. Additional information on existing bogie suspensions is given in Appendix II.\n10-2" + ] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-9-1.png", + "caption": "Figure 8-9- Dynamically Conjugate Points", + "texts": [ + " The geometrical construction shown in Figure 8-8 enables the pairs of points to be determined graphically. The hyperbola pq = ab \u2014 c2 is drawn relative to the axes XCY. The point \u00dfi corre- sponding to B on the hyperbola is projected horizontally to meet the line CZ at Ai. The projection of Ai on the Y axis give.s the point A. It is obvious that as point A approaches point C, point B will approach infinity. Similarly, as point B approaches point C, point A approaches infinity. 8-21 INERTIAL SYSTEM A similar analysis can be made with respect to dynamically conjugate points. Figure 8-9 shows a 8-14 AMCP 706-356 typical vehicular mass system M. A dynamically equivalent mass system can be selected to replace the original system. This second system must possess the same mass, moment of inertia, and position of its mass center as the original mass system. Thus a body consisting of two masses mx and m2 (with mi ~\\- m2 = M) concentrated at points E and F as shown and connected by a weightless bar can be substituted for the original mass provided that the essential dynamical characteristics are the same. The moment of inertia about its mass center of the original mass can be expressed as Mk2. If mir = m2s and m^r2 -j- m2s'2 = Mk2, then rs = k2. Since the dimension r(or s) can be chosen arbitrarily, it follows that there is an infinite number of such pairs of points. The geometrical construction shown in Figure 8-9 enables the pairs of dynamically conjugate points to be determined graphically in a manner similar to that used for the elastically conjugate points. 8-22 COMBINED SYSTEM The elastically conjugate system can be combined with the dynamically conjugate system as shown in Figure 8-10. For a given mass-elastic system, the two hyperbolas will, in general, intersect at one point L. Then the points H and /, which are projected from L, are points which are both elastically and dynamically conjugate and are termed doubly conjugate points" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001101_f_version_1688017499-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001101_f_version_1688017499-Figure2-1.png", + "caption": "Figure 2. Actuating principle of the RSEA. (a) Arc grooves design. (b) Principle of torque transfer. (c) Torque and spring deformation analysis.", + "texts": [ + " The proposed miniature compact RSEA is displayed in Figure 1. The RSEA is mainly composed of micro servo motor, driving flange, output flange, encoder, and linear springs. The driving flange is mounted on the output shaft of the micro servo motor to actuate the output flange. Two linear springs are designed between the driving flange and output flange to transmit the rotation motion in an elastic manner. The two springs are embedded in the arc grooves of the driving flange and output flange, as shown in Figure 2a. The driving flange and the output flange are assembled by a thin-walled bearing to ensure that they are concentric. As the driving flange and output flange rotate relatively, the springs will be compressed and produce a resilience. In this way, driving torque of the driving flange will be transmitted to the output flange elastically. The driving torque is a function of the relative rotation angle between the driving flange and output flange. The relative rotation angle can be measured via a rotary encoder embedded on the surface of the output flange. An output swing arm and wire wheel are designed on the output flange for the convenience of subsequent experimental research. As depicted in Figure 2a,b, two arc grooves are symmetrically designed on the driving and output flanges to achieve bidirectional actuating. Each arc groove contains a limit surface pair, those are a&b, c&d, A&B, and C&D, respectively. Limit surface pairs a&b and c&d belong to the driving flange, while A&B and C&D belong to the output flange. Under the action of the spring\u2019s resilience, limit surface A and a, B and b, C and c, and D and d will align automatically. As an external load Fo is applied to the output flange, a relative angular offset \u03b8c will appear between the driving flange and output flange. When the output flange is actuated to rotate clockwise with respect to the input flange, two springs will be compressed by limiting surfaces a&B and c&D. In the same way, two springs will be compressed by limiting surfaces A&b and C&d as the output flange rotates counter clockwise. Due to the arc grooves, the axial size from driving flange to the output flange Actuators 2023, 12, 267 3 of 12 of the RSEA can be effectively reduced, which is 11.5 mm in the presented design. As shown in Figure 2a, the springs could be embedded in the arc grooves reliably without any additional installation structures. It should be noted that the groove needs to be filled with an appropriate amount of lubricating grease before the assembly. In this way, the effect of the friction between the springs and the groove on the final force control could be significantly reduced. Thus, the whole RSEA system could achieve simplicity and compactness which will be sufficient for the applications in robotics, such as robotic hand", + " Finally, the overall dimension, weight and maximum driving torque of the RSEA are 42.5 mm \u00d7 34 mm \u00d7 62 mm, 85 g and 2 Nm, respectively. It is worth noting that for the proposed RSEA configuration, its dimension could be further reduced. However, this could lead to the decrement of the peak torque. The RSEA prototype design in this study is a balance between the dimension and actuating ability. Figure 1. 3 ill stration of the SE syste . Actuators 2023, 12, x FOR PEER REVIEW 3 of 13 Figure 1. 3D CAD illustration of the RSEA system. As depicted in Figure 2a,b, two arc grooves are symmetrically desig e on the driv- ing and output flanges to achieve bidirectional actuating. Each arc groove contains a limit surface pair, those are a&b, c&d, A&B, and C&D, respectively. Limit surface pairs a&b and c&d belong to the driving flange, while A&B and C&D belong to the output flange. Under the action of the spring\u2019s resilience, limit surface A and a, B and b, C and c, and D and d will align automatically. As an external load oF is applied to the output flange, a relative angular offset c will appear between the driving flange and output flange. When the output flange is actuated to rotate clockwise with respect to the input flange, two springs will be compressed by limiting surfaces a&B and c&D. In the same way, two springs will be compressed by limiting surfaces A&b and C&d as the output flange rotates counter clockwise. Due to the arc grooves, the axial size from driving flange to the output flange of the RSEA can be effectively reduced, which is 11.5 mm in the presented design. As shown in Figure 2a, the springs could be embedded in the arc grooves reliably without any additional installation structures. It should be noted that the groove needs to be filled with an appropriate amount of lubricating grease before the assembly. In this way, the effect of the friction between the springs and the groove on the final force control could be significantly reduced. Thus, the whole RSEA system could achieve simplicity and com- pactness which will be sufficient for the applications in robotics, such as robotic hand", + " To obtain the relation between the output torque To and the relative rotation angle \u03b8c, a model identification experiment has been conducted, as shown in Figure 3. As output flange rotates clockwise and contact with the Y-type contact of the force gauge, its rotation will be limited by the Y-type contact and apply a horizontal force Fo to the force gauge, see Figure 3a. In this way, Fo could be measured by the force gauge directly. Then, the output torque To could be obtained as To = Foro, as illustrated in Figure 2c. In experimental tests, the loading and unloading process has been repeated for three rounds to observe the hysteresis and the repeatability characteristics of the SEA system. The relative rotation angle \u03b8c between the driving flange and output flange is measured via the rotary encoder which is embedded on the surface of the output flange, as depicted in Figure 1. Actuators 2023, 12, x FOR PEER REVIEW 4 of 13 Figure 2. Actuating principle of the RSEA. (a) Arc grooves design. (b) Principle of torque transfer. (c) Torque and spring deformation analysis. According to the relative angular offset c , the output torque oT of the output flange could be given as, 2o s so s o s cT kr l r r (1) where, k , sr and sol denote the spring stiffness, radius of the spring centerline and spring original length, respectively. o denotes the angle of the arc grooves of the driving flange and output flange. It should be noted that spring stiffness k is unknown for its bending deformation", + " To obtain the relation between the output torque oT and the relative rotation angle c , a model identification experiment has been conducted, as shown in Figure 3. As output flange rotates clockwise and contact with the Y-type contact of the force gauge, its rotation will be limited by the Y-type contact and apply a horizontal force oF to the force gauge, see Figure 3a. In this way, oF could be measured by the force gauge directly. Then, the output torque oT could be obtained as o o oT F r , as illustrated in Figure 2c. In experi- mental tests, the loa ing an unloading process has been repeated for three rounds to observe the hysteresis and the repeat bili y characteristics of the SEA system. The relative rotation angle c between the driving flange and output flange is measured via the rotary encoder which is embedded on the surface of the output flange, as depicted in Figure 1. Figure 3. Experi ental platfor to easure the actuating force of the SEA system. (a) Unloading state. (b) Loading state. The polynomial model has been adopted to design the relation between Fo and \u03b8c" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004333_f_version_1650759780-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004333_f_version_1650759780-Figure2-1.png", + "caption": "Figure 2. (a) The compensation action of the robot causes the drill to bend. At the same time, the deflection force of the drill tool is also reflected to the handle and felt by the operator, (b) the deflection model of the drill tool in contact with the object surface.", + "texts": [ + " As the drill approaches the surface of vertebra to which the drill is not perpendicular, the drill tends to skid away from the target drilling path. This is partially due to improper control of the exerted force with respect to the contact force situation. Too much pushing force on the tool when breaking the slippery and stiff bone surface usually produces tool skidding. The handheld robot is even more complicated, because the robot at the same time needs to stabilize the drill against disturbances caused by involuntary hand motion. In certain circumstances, the robot may cause tool deflection when moving the tool (Figure 2a) when the tool tip is still being maintained at the touch-down location. This situation provides the wrong information by the optical tracker regarding the actual location of the tool tip with respect to desired path because the tool is presumed to be rigid. This error can subsequently cause difficulties in correcting the deviation of the tool caused by the robot, because the tool is no longer un-deformed. In this case, a tool deflection model is necessary. Figure 2b shows the tool deflection model, which describes the forces acting on the bone surface originating from the drill and takes into account the deflection of the drill bit. Drill deflection indicates that the drill is likely unable to slide freely on the surface in order to correct the entry point (shown in Figure 3). In this case, contact compliance adjustment is necessary. During entry point correction, the actuators exert actuation forces in order to move the tool, while at the same time resulting in contact forces from the bone" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001974_3_3_article-p285.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001974_3_3_article-p285.pdf-Figure7-1.png", + "caption": "Fig. 7. The connection of involute curves", + "texts": [ + " The maximum Hertz stress (Equivalent stress) can be calculated in the case of toothed gear pairs by the following formula [11]: \u03c3 2 H \u00bc 0:35$ Fn l $ 1 r1 \u00fe 1 r2 1 E1 \u00fe 1 E2 (5) Consequently, the characteristic of the involute curve is that the common normal line of the connecting tooth curves touches the base circle diameters (db1, db2) from which the involute curve can be generated (Fig. 6). The Pythagorean theorem can be useable for the O1N1C and the O2N2C rectangular triangles to determine the r1 and r2 involute curvatures on the common contact point which is the common tangent point of the rolling circles (Fig. 7): dw1;2 2 2 \u00bc r21;2 \u00fe db1;2 2 2 \u2192 r1;2 \u00bc ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi dw1;2 2 2 db1;2 2 2 s (6) r1 \u00bc 22:778mm; r2 \u00bc 34:169mm The load moment from the pinion affects the gear along the perimeter of the rolling circle diameter of the pinion. The circumferential force can be calculated by the following formula: M \u00bc Fc$ dw1 2 \u2192 Fc \u00bc 2$M dw1 \u00bc . . . \u00bc 1315:594N (7) Based on Fig. 8 the normal force is Fn \u00bc Fc cosaw \u00bc " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.52-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.52-1.png", + "caption": "Figure 5.52: Final idea of how 3:1 could look like", + "texts": [], + "surrounding_texts": [ + "5.11. Refinement and finalization of concepts 81", + "Refinement of concept 3:1, which can be viewed below in figures 5.52, 5.53 and 5.54. The footprint of the L-profiles has been enlarged and walls thickened. The supports have been slimmed down for a better fit in tight spots and the function of the corner fasteners has been tweaked for better visualization.", + "5.11. Refinement and finalization of concepts 83" + ] + }, + { + "image_filename": "designv7_3_0000345_f_version_1651916906-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000345_f_version_1651916906-Figure1-1.png", + "caption": "Figure 1. The Serpent 1 robot with all attached frames.", + "texts": [ + " In this section, a Serpent 1 robot is selected as an illustrative object, and its quasi-physical model will be built. The SCARA Serpent 1 robot has three rotary joints using servomotors. The robot end-effector can be moved vertically by a pneumatic cylinder. This study concentrates on the problem of actuator torque loss; therefore, the pneumatic cylinder can be inactive. In fact, this neglect does not affect the position and orientation of the end-effector (EE) projected on the working plane. The initial configuration of the Serpent 1 robot with attached-body frames is depicted in Figure 1, and the D-H parameters are described in Table 1. 1 In Figure 1, besides the base frame, which is O0x0y0z0, another fixed frame Owxwywzw (called the world frame) is also depicted with a0 = 0.15 and d0 = 0.3725. Based on the three-dimensional CAD assembly files of the Serpent 1 robot depicted in Figure 2, the approximated values of mass mi (kg), body centroid rCi (m) with respect to the attachedbody coordinate system, and inertia tensor Ii (kgm2) can be obtained by any professional mechanical design software. In this way, the nominal values of robot parameters have been achieved and are shown in (24): Base : m0 = 7" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003149_eureca2018_02023.pdf-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003149_eureca2018_02023.pdf-Figure8-1.png", + "caption": "Fig. 8. F450 frame.", + "texts": [ + "096 m2 The Aspect Ratio of the horizontal tail is taken as 3. The subsequent calculations to find tail span and tail chord are the same as Equation (2) and (3) respectively. This gives bht = 0.53 m and Cht = 0.18 m. For the Elevator sizing, the the suitable Elevator area, Se = 20% of Sht Therefore, Se = 0.096*0.2 = 0.0192 m2 be = (0.0192*3)0.5 = 0.24 m Ce = 0.0192/0.24 = 0.08 m 3.8 Fuselage Design The fuselage does not have any specific calculations as the prototype will use the F450 quadcopter frame (Figure 8) as the base fuselage. This frame\u2019s aerodynamic shape can be improved to cater for the horizontal flight mode by covering 10 the centre hub using light materials and incorporating shape that can improve lift and reduce drag. Covering the centre hub also protects the exposed main electronics part such as the flight controller unit, battery, GPS unit and power distribution board. 3.9 Material Selection Key and critical parameters in the design of such UAV is choice of material. Every single part of the smallest item such as a screw to the largest part such as a wing, weight is the critical factor when coming to selection" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000224_LobsterMechanics.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000224_LobsterMechanics.pdf-Figure1-1.png", + "caption": "FIGURE 1. Bio-inspiration from anatomical structure of lobster\u2019s abdomen and geometric parameters that can influence the behavior.", + "texts": [ + " Crustaceans such as lobsters swim under water through the flapping motion from their abdomen with a backward propulsion as a startle-escape response [19,20]. These tail-flips are brought about by soft muscle\u2019s rapid alternate extensions and flexions within their abdomen, pushing or dragging rigid exoskeletons to move in a rotary trajectory [21]. The anatomical structure of lobster\u2019s abdomen leads to the design of the proposed hybrid actuator including rigid shell segments outside and a soft actuator inside, as shown in Fig. 1. The soft chamber inside provides necessary actuation like the abdomen muscle of a lobster, while the rigid shell segments serve multiple purposes to combat the disadvantages of soft actuators with preserved advantages in rigid robotics [22, 23]. In the rest of this paper, section 2 explains the design principles and fabrication procedures of this hybrid actuator. In section 3, a quasi-static model is proposed to analyze the bending actuation and tip force exertion of this hybrid actuator, along with its forward kinematics", + " This mechanism defines a precise bending trajectory for the hybrid actuator, making it comparable to a robotic manipulator with known forward kinematics during bending motion. As a result, this makes the hybrid actuator fundamentally different from most existing soft actuators whose continuous deformation is beyond the capacity of traditional robotic theory. We design a novel folding mechanism with inspirations from lobster\u2019s shell pattern to provide an improved protection to the soft chamber inside. As shown in Fig.1, the fractured sphere shells are foldable into an adjacent segment\u2019s half cylinder chamber before actuation. Once actuated by pressurizing the soft chamber inside, the inflated soft actuator expands and pushes the edge of the fracture sphere shells to rotate around the joint axes to accomplish a bending motion. The half cylinder chambers along with the fractured sphere shells can fully envelop the soft chamber throughout the range of bending motion, and excessive local stretch is therefore completely avoided", + " Finally, the soft chamber was inserted into the 3D printed shells to form the hybrid actuator (Fig. 2(c)). The contact surface between soft chamber bottom and each shell segment was glued to ensure a consistent stretch along the soft chamber under actuation. The hybrid actuator design can be tuned by changing several geometric parameters including internal width and length of the soft actuator, wall thickness, the distance between two axes, shell inner radius and the distance between the joint axis and soft actuator bottom (see Fig. 1). Geometric parameters chosen in this design was based on a further application in a robotic glove. Therefore, several geometrical parameters are determined by the hand size of the researcher involved. With the introduction of rigid constraints, computationally inexpensive analytic models and forward kinematics of the hybrid actuator are pursued to estimate and predict its mechanical performance. Once inflated by pressured air, the soft chamber will expand to conform to the internal space of the rigid shells, and the actuator will then either bend or exert force when in contact with external objects" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002726_4_Paper22103-108.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002726_4_Paper22103-108.pdf-Figure6-1.png", + "caption": "Fig 6 At 85.944 Hz", + "texts": [], + "surrounding_texts": [ + "By stress analysis, minimum and maximum normal and shear stress values occurring at the fracture surface during operation is investigated. At first, forces and torques acting on the mount are determined. By analyzing minimum stress value, only the weight of the empty cabin (420 kg) and balance weight (310 kg) is considered. Shear forces, caused due to the loads of empty cabin, ropes and balance weights, forms a shear stress of 7.69 MPa. By analyzing maximum stress value, balance weight, cabin weight with four persons inside (each person is 80 kg and the total weight of the cabin is 740 kg), torsion moment and impact ratio is considered." + ] + }, + { + "image_filename": "designv7_3_0004479_f_version_1679279622-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004479_f_version_1679279622-Figure3-1.png", + "caption": "Figure 3. The series connector of the SWC robots.", + "texts": [ + " A DC motor (rated voltage: 6 V, rated torque: 0.6 kg \u00b7 cm) was installed in the motor base, and its output shaft rotates three gears with a gear ratio of 4:7. The lowest gear rotates the helix, which produces the wave-like locomotion through the links. In particular, the motor tail is connected to an encoder, which can accurately measure the motor speed. In this subsection, two connection structures of the SWC robot are introduced, including the series and parallel connections. A. The Series Connection Figure 3 illustrates the series connector\u2019s mechanical structure, which was designed to enable the SWC robots to perform more complex tasks, such as crossing gaps and climbing steps. The series connector mainly consists of an active lock and an arc slider. The abovementioned active lock comprises a sliding rail, two linear servo motors (working voltage: 5 V), and two sliding blocks. Two arc guide rails were designed at the end of the arc slider to improve the fault tolerance of the docking. The number of robot modules must be at least three to ensure the stability of the robot\u2019s center of mass" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure5-4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure5-4-1.png", + "caption": "Figure 5-4. Wheel Ground Pressure Distribution", + "texts": [ + " This illus- trates that the addition of a road wheel midway between two wheels produces a greater sinkage at the midpoint than occurred before the additional wheel was introduced, but it results in a reduction of sinkage at all other points. The net result is a more uniform track sinkage and a more uniform pressure distribution under the track. Equations 5-14 and 5-15 are based upon the assumption that the track is perfectly flexible. Actual tracks possess considerable rigidity which helps distribute the load more uniformly and reduces the necessity for a large number of road wheels. p = ^+\u00dc[\u00ab,-r(l-eoif)]' (5-17) The resulting pressure distribution is of the form shown on Figure 5-4. This, of course, represents an extreme case. In practical cases, the track will have some rigidity and tension due to sinkage of adjacent wheels which will limit the ability of the track to conform to the wheel shape as it sinks into the ground. Both of these effects will lead to more uniform pressure distribution under the wheel and a reduction in the maximum wheel sinkage. In general, however, the distribution of load under a track in the longitudinal direction is not uniform but varies with the design of the track support, the track flexibility, and with the soil parameters fcc, k$ , and n. 5-9.3 SINKAGE AND LOAD DISTRIBUTION UNDER WHEELS Consider again the case of the vehicle at rest (only vertical forces need be considered), and assume that the track is flexible and loose enough to wrap freely around the wheel as it sinks into the ground (Figure 5-4). The ground pressure at any point is, by Equation 4-5, V (\u00a5 + *) From Figure 5-4, neglecting the thickness of the track, z = z0 \u2014 r(l \u2014 cos 0) Substituting into Equation 4-5, (5-16) 5-10 STEERING OF TRACKED VEHICLES 5-10.1 GENERAL DISCUSSION All current standard military tracked vehicles use laterally rigid tracks. The most serious basic limitation on the performance of these vehicles is the almost universally used skid-steering method of maneuvering. Steering is accomplished by controlling the relative speed of the tracks to reduce the net longitudinal thrust of one track and, if possible, increase the longitudinal thrust of the other track" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001384_f_version_1675951287-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001384_f_version_1675951287-Figure5-1.png", + "caption": "Figure 5. The sketch representing the body frames of the virtual isolated bodies.", + "texts": [ + " Based on the Lagrangian formulation, the closed-form dynamics in terms of the quasi-coordinates is established. Then, the principle of virtual work and the relationships between the active and passive prismatic joint variables are employed to eliminate the dependent coordinates (three passive prismatic joint variables). Finally, the closed-form dynamic model for the 2R1T 3PPS PKM with a rigid\u2013flexible structure in terms of the three active prismatic joint variables is established. As shown in Figure 5, body frames fixed at center of mass (COM) of the three active prismatic joints are numbered from 1 to 3, body frames fixed at COM of the three passive prismatic joints are numbered from 4 to 6, body frame 7 is fixed at the COM of the moving platform with the same orientation as the frame M, and the fixed base frame B of the 2R1T 3PPS PKM is labeled as frame 0. The quasi-coordinates q \u2208 <6\u00d71 are represented by q = qa1 qa2 qa3 qp1 qp2 qp3 = q1 q2 q3 q4 q5 q6 (18) The kinetic energy and potential energy of each body are expressed in the base frame" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001895_9312710_09495824.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001895_9312710_09495824.pdf-Figure1-1.png", + "caption": "FIGURE 1. Modeling of a screw-based crawling robot.", + "texts": [ + " The experimental results and analysis are presented in Section 4. Finally, the significance and conclusions of this study are presented in Section 5. II. THE PROTOTYPE OF THE SCREW-BASED CRAWLING ROBOT In this section, a prototype of the screw-based crawling robot is described. This prototype borrows the form of a robot studied by Os\u00edski and Szykiedans [2] from several previously studied types of screw-based crawling robots. A. PROTOTYPE OF SCREW-BASED CRAWLING ROBOT The model of the screw-based crawling robot used in the experiment is shown in Fig. 1. The dimensions of the screw-based crawling robot are 165.28 mm, 217.72 mm, and 80.94 mm (except for the wheel\u2019s blade, laser sensor reflector, and weight basket). The screw wheel is powered by two geared motors with an encoder. A DC motor (IG32GM+ENCODER 05TYPE (12V), D&J WITH Co., Ltd.) is used, and its specifications are shown in Table 1. Power without any problem with driving is supplied through the power-supply. For convenience, the screw wheels can be easily attached and detached in the experiment", + " The size of the test bench considered the size of robot, to avoid interfering with the test\u2019s progress. The structure of the test bench is shown in Fig. 4. In the controller part, the motor is controlled through a motor drive. A dual VNH3SP30 motor driver carrier MD03A was used as the motor drive. Guide profiles were used to compensate for the 1-axis straight-forward motion of the robot. An OSTSenVL53L1X sensor was used for speed measurement, and its specifications are listed in Table 2. The laser sensor reflector shown in Fig. 1 was used along with the laser sensor to receive real-time speed data. To emulate a granular surface, sand was piled up approximately 50 mm from the bottom of the test bench. The sand was composed of river sand from the Nakdong River, which is available in the market. This sand is classified as dry sand, with a size of 0.2mm-0.7mm, similar to 0.1mm-1mm for granular particles such as desert sand [24]. In each experiment, the same starting conditions were ensured by flattening the sand prior to the start of the velocity measurement", + " Since the goal of the experiment was to obtain the robot\u2019s maximum speed, we used Equation (1) as follows. S/Nratio = \u221210log \u2223\u2223\u2223\u2223\u2223\u2223\u2223 ( 1 y1 )2 + ( 1 y2 )2 + \u00b7 \u00b7 \u00b7 ( 1 yn )2 n \u2223\u2223\u2223\u2223\u2223\u2223\u2223 [dB] (1) where the yi value is based on the experimental measurements, which is the forward distance per revolution (mm/rev), and i represents the i-th repeated experiment. n represents the total number of experiments. IV. RESULT OF EXPERIMENT The results of the experiment are presented in Table 5. The speed data were measured using the laser reflector, as shown in Fig. 1, and the laser sensor is shown in Fig. 4. Data at the beginning and the end were excluded to obtain stable speed measurement data. The forward distance per revolution was calculated by dividing the measured speed by the rpm value. The experiments were repeated three times to improve their reliability. Based on these values, the S/N ratio was calculated using Equation (1). VOLUME 9, 2021 103991 TABLE 5. L9 ( 34 ) Taguchi orthogonal array. Fig. 7 shows the S/N ratio for the design parameters. The most sensitive parameter was the number of spirals, which tended to decrease as the number of spirals increased" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001650_32489_FULLTEXT01.pdf-Figure16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001650_32489_FULLTEXT01.pdf-Figure16-1.png", + "caption": "Figure 16. Corrected epicycloid transmission (Alipiev, 1988)", + "texts": [ + "Used symbols Symbol Explanation Dimension Note Angle of motion transmission deg Coefficient of non-centrodidity - Correction coefficient of - - Gearing conditions Every epicycloidal gear meshes correctly if: 1. The radius of the circle on which the centers of the pins are located is equal to the pitch center distance; 2. The radius of the pins is equal to the form generating circle; 3. The difference between the number of teeth of the epicycloidal wheel and the number of pins must be equal to 1; 4. The center distance is equal to the eccentricity i.e. ( (Eq 2.1.43) On Figure 16 is shown an epicycloidal gearing, where and are respectively the radii of the centrode circles of the epicycloidal and the circle on which the pins are located. These circles are starting circles. Since : , (Eq 2.1.44) 23 Biser Borislavov, Ivaylo Borisov, Vilislav Panchev for the radii of the base circles we have : (Eq 2.1.45) (Eq 2.1.46) After taking into consideration the equation (Eq 2.1.43) we can determine the formulas for the radii of the base circles ( (Eq 2.1.47) ( (Eq 2.1.48) - Dimensions of the housing All these dimension can be determined only with the basic parameters m, , x, " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003053_f_version_1614169697-Figure10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003053_f_version_1614169697-Figure10-1.png", + "caption": "Figure 10. Displacement values in the humanoid foot.", + "texts": [ + "57 \u00d7 106 N/m2 is observed in the upper part of the rigid midfoot, next to the connection to the compliant body. The maximum value is significantly smaller than the yield limit of the material, thus validating the proposed humanoid foot for an average walking gait. The behavior of the impact of the foot on the ground is obtained by applying the mean angle displacement taken from the analyzed subjects (see Section 2). The results can be observed in the step-by-step effect of the load on the different bodies of the humanoid foot, as is shown in the linear displacement distribution reported in Figure 10: \u2022 Starting from the rigid body of the hindfoot, the angular displacement is applied to the ankle joint. The hindfoot is connected to the flexible body of the midfoot, which starts to deform. \u2022 When the angular displacement causes the foot to hit the ground, the midfoot is characterized by a stress concentration in the upper part, as per Figure 9. \u2022 The arc bottom part of the foot is loaded with a maximum tension of 1.57 \u00d7 106 N/m2, behaving as the human foot muscle when stepping. \u2022 The spring connecting the two bodies of the forefoot is stretched", + " By using the real dimension of the marker, i.e., 10 \u00d7 10 mm, the motion in pixels is converted to real-world one with a semi-automated tracking process, which has an estimated accuracy of 5% (measured through a checkerboard calibration). A 1-second stance cycle was manually reproduced, moving according to the motion in Figure 16, which was measured with the camera during the experiment. During the load cycle, the marker moved 9.5 mm, with a comparable motion to the corresponding point in the analysis in Figure 10. The action of the foot on the ground, measured with the load cell, was reported in Figure 17. The vertical ground reaction force applied to the foot is bimodal, with an initial impact peak, followed almost immediately by a propulsive peak as the foot pushes off against the ground. In a conventional humanoid robotic foot, this impulsive force is transmitted fully to the ankle, with the risk of disrupting the robot\u2019s balance. Conversely, the proposed foot is able to dampen this impact through the spring and the compliant body, significantly reducing the stress on the ankle joint" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003743_30457_FULLTEXT02.pdf-Figure2.8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003743_30457_FULLTEXT02.pdf-Figure2.8-1.png", + "caption": "Figure 2.8: Diagram of 2D mode coupling chatter [27]", + "texts": [ + " Frictional chatter: The slip-stick force between the tool and the workpiece can cause oscillations which are commonly called the \u201cdry friction\u201d response amongst machinists. Lubricating the system can minimize this effect and create stability. 2. Regenerative chatter: The most common and researched source of chatter for the past sixty years [26], this type of chatter is caused by the interaction of the approaching tooth and the wavy surface created on the workpiece by the returning tool as depicted in Figure 2.7. 3. Mode-coupling chatter: This type of chatter is caused by the coupling of two vibration modes during operation as portrayed in Figure 2.8 [27]. The system vibrates at the resonance frequency in this case, making mode-coupling chatter hard to distinguish from external force excitations of the system. 25 | Literature Review and Theoretical Background 4. Thermomechanical chatter: Induced by the thermal expansion and contraction of the tool or workpiece during machining processes, these effects often become more apparent when extreme operation parameters such as depth of cut are considered. 26 | Contact Applications Involving Robotic Manipulators There have been recent attempts in modelling robot manipulators utilized for contact applications", + " The influences of the machining process on the combined system The dynamics and mechanics of the robotic manipulator have been studied previously as discussed before [13, 22]. The machining process response can be defined based on the observations of Pan et al. [36] and a derivation from Stone [25] which yields: 2 1 1 1 1 1 1 1 2 ( )2 ( ) ( ) ( ) ( ( )cos ( )sin )cos d x t dx t m c k x t Rb x t x t dt dt \u2212+ + = \u2212 + (2.19) 2 2 2 2 2 2 2 1 2 ( )2 ( ) ( ) ( ) ( ( )cos ( )sin )sin d x t dx t m c k x t Rb x t x t dt dt \u2212+ + = + (2.20) where equations (2.19) and (2.20) represent the oscillations of the tool in the two main modal directions as seen in Figure 2.8. b is the contact length and R is the constant cutting force coefficient. By following this depiction, the depth of cut (d) can be simply modeled as: 1 2( )cos ( )sind x t x t = + (2.21) which models the mode-coupling chatter observations of Pan et al. [36] in a theoretical fashion. The range of motion increases exponentially when chatter occurs and therefore the depth of cut would change in an oscillatory motion which leads to the chatter marks as observed in Figure 2.13. Chapter 3 This chapter focuses on presenting the simulation and experimental setup and approach towards analysis of the results in the current study", + " Producing a detailed mapping of the joint-space can lead to a satisfactory estimation of the robot behavior in the workspace as discussed in the previous section. The following section will focus on modelling contact applications utilizing a robotic manipulator to provide a deeper understanding of the combined operation behavior. Contact applications can be modeled based on the results of the literature survey and previous experiments involving robotic manipulators. In this study, the interaction of the robot TCP with the workpiece is modeled according to Figure 2.8 with the goal of modelling the chatter behavior of the robot and assessing the dynamic behavior of the TCP in these applications. The following models are created to provide a low-level and high-level understanding of the architecture of interactions between the tool and the workpiece in chatter behavior: \u2022 Combined 1-DOF model: This model was made according to equations (2.19) and (2.20), with the oscillations being divided into two respective DOFs. This model allows the understanding of low-level interactions and provides more insight into the nature of selfexcited vibrations in contact applications. \u2022 2-DOF model: This model was constructed with respect to Figure 2.8 as an abstract model to visualize and provide a higher-level understanding of mode-coupling chatter. The movement of the TCP and interactions of the two modes can be seen in the oscillation plane in this model. The objective of this study was to measure and quantify the influencing properties on system behavior. As noted by previous authors [36], the lower stiffness value of the manipulator when compared to CNC machine is of concern in contact applications and stability criteria should be derived based on modelling and simulations" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003053_f_version_1614169697-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003053_f_version_1614169697-Figure7-1.png", + "caption": "Figure 7. Ankle joint axis of the CAD model, on which the input motion is applied.", + "texts": [ + " The mean angular displacement of the ankle acquired from the subject was used as the input motion for the nonlinear dynamic simulation. The definition of the time curve for the angle displacement application was set to simulate the mean step duration for 0.63 s, using a force control technique. The input given to the simulation was extracted by the gait analysis data, and it corresponds to the average gait of Figure 3. The input motion was applied to the ankle joint axis, which is highlighted in blue in Figure 7. The humanoid foot is composed of four bodies, three of which are in ABS rigid plastic (Table 2), and the middle of which is set to thermoplastic polyurethane (TPU) for his flexible mechanical properties, simulating the muscle part. Another key component is the spring\u2014shown in Figure 8\u2014in the forefoot, which passively improves the ability of the foot to adapt to the ground; the spring was modelled with a 2 mm diameter, five coils, and an 8 mm length, and alloy steel was chosen as material in order to simulate a commercial part" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000827_f_version_1624432525-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000827_f_version_1624432525-Figure5-1.png", + "caption": "Figure 5. The elements of the platform are the soft joint (1), a metal base (2), motors (3), electronic elements to feed and control the motors (4) and other connective elements such as motor supports (5), joint bases (6) and tendons (7).", + "texts": [ + " The linear displacement is transformed into an angular displacement by the length of the arc formed by the circumference of the winch for a certain angle (Figure 4), following the equation below: \u2126 = (Lo \u2212 Li) R (1) R is the radius of the winch where the tendon is wound or unwound, in this case 9.3 mm, and \u2126 is the angle that provides that displacement. To choose the soft joint operation, a test platform was designed. The goal is that the rest position of the joint is horizontal. Three motors will be used to operate the joint by tendons, each of which will wind the three tendons (Figure 5). The fixing base is made up of two 3 mm thick metal plates, to be strong enough to support the test loads. The motors used for the drive are Maxon EC-max 22. The motors are controlled by Technosoft\u2019s Intelligent Drives iPOS 4808 MX, which communicate with the PC via busCAN. Connecting elements have been printed on a 3D printer Creatbot600 pro and Zmorph from PLA (Polylactic acid) material. They are two bases for fastening the soft joint with the metal base, a platform for fastening the electronic elements, three motor fasteners with the metal platform and three winches that are attached to the motor shaft and the tendons, made of polyester thread, for the activation of the joint" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004244_Bhattacharya_MSc.pdf-Figure3.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004244_Bhattacharya_MSc.pdf-Figure3.1-1.png", + "caption": "Figure 3.1: An N link constrained serial chain with axial and transverse loading", + "texts": [ + " A realistic view of the vertebrae column would require each segment to have all six degrees-of-freedom (DoF) at each joint if the constraints due to the muscles and tendons are ignored [26]. However, this is computationally intensive. Furthermore, many of the DoFs in the 6-DoF model are unnecessary. To simplify our modeling, we consider the spine to be a multi-body serial manipulator with rigid segments and joints with some limits to the angle of rotations at the joints. We also assume that the joints have torsional springs that offer resistance to the rotations at the joints. Figure 3.1 shows a N link serial chain with one end fixed and the free end subjected to a horizontal force resulting in a desired end motion. The rotations at the joints, \u03b8i, are with respect to a horizontal X axis and hence are absolute rotations. Each joint has an associated lumped stiffness Ki and a lumped damping Ci. At each joint, there is a loading along the negative Y axis denoted by PY which the structure must be capable of bearing in addition to the self-weight. The desired end motion is denoted by \u03b4X and this is due to a horizontal actuating force PX " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000798_37295_FULLTEXT01.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000798_37295_FULLTEXT01.pdf-Figure3-1.png", + "caption": "Fig. 3 : Automated leveling is achieved when the robot endeffector pointing vector is aligned with the horizontal axis of the inertial frame {B}", + "texts": [ + " In this work we mainly focus on experimentally validating that the proposed control method can be used to identify the position of the \u201chuman joint\u201d in human-robot object co-manipulation. The use of the online estimates of the constraints imposed by the human can be used to achieve a specific control objective. An example described in the following section is the automated leveling of an object jointly held by a human and a robot. Here, we define leveling as aligning the end-effector frame of the robot with the horizontal axis of the world frame, while jointly holding an object, see Fig 3. In early work [4], leveling has been dealt with by controlling the orientation of the robot end-effector so that the pointing vector becomes parallel with the ground; the problem is solved by considering that the axis of motion is known with respect to the end-effector while the inexact knowledge of the distance between the human and the robot grasping points can only deteriorate the rate of convergence. Here we deal with the leveling problem [4] but we consider that the robot is not aware of the center of rotation, i", + " 2) The desired torque \u03c4d is set zero. If we consider the case of symmetric human and robot grasping points with respect to the center of mass of the object modeled as a beam, human and robot will share the load. 3) A projection operator that does not affect the convergence and stability properties of d\u0302 is used on (10) in order to ensure that d\u0302(t) 6= 0, \u2200 t. 4) The desired velocity used in the feedforward terms of the controller is replaced by a feedback term based on the leveling angle \u03d1 \u2208 (\u2212\u03c0/2, \u03c0/2) shown in Fig. 3 which is the angle between a horizontal line and the pointing vector, defined as follows: \u03d1 = arcsin ( y>h y ) (12) where y is the vertical axis of the inertial frame (i.e. [0 1]>) expressed at the end-effector frame. Instead of calculating the angle \u03d1, sin\u03d1 can be alternatively used in the controller, i.e.: vd = \u2212 \u03b1 d\u0302 sin\u03d1 = \u2212\u03b1 d\u0302 y\u0302>h y (13) where \u03b1 is a positive control gain that is modulated by d\u0302 to enable the system a convergence rate independent of kinematic parameters of the task. Particularly, the convergence of the leveling angle to zero is described by the following differential equation: \u03d1\u0307 = \u2212 \u03b1d c\u03d5\u0303d\u0302 sin\u03d1 (14) which implies that \u03d1 \u2192 0 since c\u03d5\u0303 > 0, d\u0302 > 0; thus the leveling objective can be achieved independently of the learning objective", + " In scenario B, the human agent starts by moving the object, and the robot estimates the constraints on-line while following the action initiated by the human. 1) Scenario A - Estimation of Kinematics of Passive Human: In the first scenario, we demonstrate the capability of the proposed method to estimate the constraints imposed by a human on a jointly held object. The human is passively holding one end of a 95 cm long wooden board, with a mass of 2.75 kg, and the robot has a fixed grasp of the other end, see Figure 3. The task for the robot is to actively rotate the board around the virtual vertical axis imposed by the human at point ph. We run two experiments in this scenario. In both of these experiments, the controller was run using \u03b3 = 700, \u03b3d = 1000, \u03b1f = 0.001, and \u03b1\u03c4 = 0.002. In experiment 1, the human agent keeps arms fixed and lets the board rotate around the grasping point (ph1 in Figure 4). The point ph1 was marked with a visible spot on the board, at [0 0.81]> in the end-effector frame, and a laser pointer was fixed to the ceiling and set to point to the spot" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001863_f_version_1690282100-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001863_f_version_1690282100-Figure1-1.png", + "caption": "Figure 1. Structure diagram of the amphibious robot. The robot is mainly composed of a hollow helical propulsion drum, a chain drive structure, a mechanical-arm-type garbage collection shovel, a waterproof box, and the main hull.", + "texts": [ + " The spiral-propulsion-based amphibious intelligent robot for garbage cleaning proposed in this paper aims to automatically collect floating debris on the water surface and debris in areas such as coastal regions, lakes, and mudflats. Conventional garbage collection vessels are ineffective in these regions, due to their shallow depths, low water disturbance, and sandy terrain. To address these challenges, a structural design is proposed, consisting of a hollow spiral-propulsion drum, a chain drive structure, a mechanical-arm shovel for garbage collection, a waterproof box, and the main hull (Figure 1). Figure 2 illustrates the overall working schematic of the spiral-propulsion-based amphibious intelligent robot. It can be remotely controlled through a PC host or a mobile app, to clean garbage on the sea surface. The rotation speed and direction of the spiral roller can be adjusted to control its movement, while the mechanical bucket arm collects the garbage. By combining the spiral roller and the mechanical bucket arm, the robot can transport litter from the water surface to the shoreline. The robot can collect garbage from the sea surface and shoreline areas, transport it to a designated collection area, and continue executing instructions for garbage collection" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003064_m_20Instructions.pdf-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003064_m_20Instructions.pdf-Figure12-1.png", + "caption": "Figure 12 Slip Insertion System Figure 13 Threaded Insertion System", + "texts": [], + "surrounding_texts": [ + "Two types of collet assemblies are available for the Tyler Calibration System: (1) a threaded insertion type which is the standard for the system (and for which the foregoing instructions are intended), and (2) a slip insertion type available as an accessory. As the names imply, the threaded insertion system screws into the threaded sleeve of the fixation post, while the slip insertion system slips into the threaded sleeve of the fixation post. In all other respects they are identical. Each type has its advantages: The Threaded Insertion System may be installed prior to placing the combined alignment and fixation frame over the patient\u2019s head. The needle guides cannot be dislodged or pushed out of the insert inadvertently and they are immediately available as soon as the frame is immobilized on the patient. Because the collets are fixed in position until unscrewed, only the calibrated needle guides can be pulled away as the weal of anesthetic forms under the skin and therefore the relative position of the needle guide in the collet is not maintained. This means that the measurements denoting fixation screw length with this system must be noted and recorded prior to injection. The Slip Insertion System can be installed very quickly following immobilization of the frame, and when creating a \u201cbubble\u201d of anesthetic at the injection site, the entire collet can be pulled away as the bubble of anesthetic forms under the skin without changing the relative position of the needle guide in the collet. The screw length indication at each site is therefore preserved as the guide assemblies are removed and may be referenced subsequently. Tyler Alignment & Calibration System with Leksell Fixation Frame" + ] + }, + { + "image_filename": "designv7_3_0004875_8948470_09184789.pdf-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004875_8948470_09184789.pdf-Figure12-1.png", + "caption": "FIGURE 12. Tool path and machined contour simulated in MATLAB.", + "texts": [ + " Then, the coordinate values are transformed into the flange coordinates in world coordinate system, and in this coordinate mode the joint variables are calculated through inverse kinematic solution, driving the robot model to move, as shown in Fig. 11. Themotion simulation shows that robot\u2019s motion accords with the expectation of V-shaped cutting process. The machined contour is simulated by 2D graphic calculation based on the tool path coordinate data and the workblank model in MATLAB. The simulation results of the machined contour and tool paths are shown in Fig. 12. Blue lines mean the tool paths generated by post-processing, and as a comparison, the red lines mean the tool paths generated by NX. The difference between the two paths indicates the effect of post-processing for V-shaped cutting. Simulation results of machined contour verify the accuracy of the robot machining files generated by the post-processing program. IV. EXPERIMENTAL VERIFICATION A. ROBOT MACHINING EXPERIMENTS An experiment on KUKA KR2210 robot is conducted to verify the path planning" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-50-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-50-1.png", + "caption": "Figure 10-50. Grouser Side of T9JE3 Track With Pad Detached", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\ndetailed tabulation of standard track types and their design characteristics is given in Appendix II.\nBlocks, as used in double-pin tracks, compose the basic track body. When two blocks are assembled on the bushings and track pins, as shown in Figure 10-46, the unit is known as a link. The link, end connectors, wedges, and capped center guide are called the shoe assembly. Blocks may consist of rubber on both sides (Figures 10-48 and 10-49), of a steel face and rubber back (Figure 10-46) or of an all-steel construction. A grouser (chevron) is a raised segment on the tread surface of the block, which affords increased traction over a smooth tread surface. In the T91B3 track the detachable pad functions as a grouser. All current tracks are rubber-bushed with 0.187-inch-thick, doughnut-type bushings.\nIn the T91E3 single-pin track the basic metalrubber structure is called the body. When bushings are added, the assembly is known as a link and is comparable to the link of the double-pin rack. The link, pin, nuts and washers (Figure 10-47) make up the shoe assembly.\nCenter guides are either bolted to or integral with the top of the body (T91E3 track), or attached by caps to the pins (T96 and T84B1 tracks). In\nthe latter case the capped guide not only functions as a track retaining component but as an additional connecting unit. Outer guides are sometimes incorporated at the extremities of the links, and are made integral with end connectors of double-pin tracks and integral with the body or link of singlepin tracks.\nBinocular frames arc metal tubular units with webbed ends, and are designed to contain the bushings and pins of double-pin tracks. The binocular frame provides support for all-rubber blocks or fabricated rubber-steel combinations. In Figure 10-51 the rubber road wheel surface is removed to show binocular construction.\n10-37 OTHER TYPES OF TRACKS\n10-37.1 FLEXIBLE PIN-JOINTED TYPE Most foreign tank tracks, at least through the World War II period, were of the flexible pinjointed type. This track consists of a chain formed of a series of rigid links connected by hinged joints. These hinges are formed by passing a pin through interlocking links, or through adjacent rigid links. The links may be identical or may be of two different types, alternating around the track. This\n10-66", + "AMCP 706-356\nlatter construction is referred to as a \"two-piece link\".\nCharacteristics of pin-jointed tracks are strongly dependent upon track pitch (distance between corresponding points of neighboring joints). Pitches of different tracks vary from about 1%\nin. to 10 in. These tracks bend into a polygon, rather than into a smooth eurve, when deformed.\nFlexible pin-jointed tracks may be subdivided into \"dry pin\" and \"lubricated\" types of track. In most modern tracks, the pin is without lubrica-\ntion and friction arises as the metal surfaces move with respect to each other. Track power losses are high and this type of track wears out rapidly. In the past, designs involving lubricated and sealed pins have been produced ; however, such systems are not in general use today because of the good service obtained from the rubber-bushed track.\n10-37.2 IRREVERSIBLE TYPES (ELASTIC GIRDER AND RIGID GIRDER)\nAll of the track types discussed previously were free to bend in either direction. In the rigid girder track, the links are so interlocked as to permit the track to form a convex, but not a concave, curve. The ground pressure under a short-pitched pin: jointed track, or a continuously flexible track, is greatest directly under each road wheel because the track is relatively free to bow upward between them. A rigid girder track is designed to prevent such upward bowing, and the portion of the track between the road wheels remains in contact with the ground.\nThe rigid girder track cannot be used with a sprung suspension system, which permits road wheels to displace vertically, since this would place an overload upon the unsupported girder when\n10-67", + "AMCP 706-356\npassing over hard obstacles. Its application has been restricted to very slow-moving vehicles such as life-boat carriers and log trailers. It has been suggested that a rigid-girder tracked vehicle be built with the road wheels all mounted on a single rigid unit with suspension springing between this unit and the vehicle hull.\nThe elastic girder track is similar in principle to the rigid girder track; however, in this case, the joints incorporate rubber blocks which tend' to make the track assume a slightly convex curvature. Normal track loads cause this track catenary to flatten out so that ground pressure is more evenly distributed. A slight amount of flexibility is present which permits the track to adjust to rough, hard terrain.\n10-37.3 CONTINUOUSLY FLEXIBLE OR ENDLESS BAND TYPE\nThis type of track consists of a continuous band which is flexible at any point along its length rather than a series of rigid links that are flexible only at their pin-connected joints. The band is usually formed of fabric or steel-reinforced rubber. The use of the band track has not been as widespread as the block and pin type; therefore, the development of this type is not as advanced. However, the recent emphasis for greater speed and air transportability of military vehicles makes the use of the band track more attractive.\nThere are three basic types of band tracks (a) flexible friction drive track, (b) rubber band\ntrack, and (c) band-block track. These are discussed in the paragraphs which follow.\n10-37.3.1 Flexible Friction Drive Track The distinguishing characteristic of this track is that stiff lateral members are not employed. This track, like most band tracks, is usually made up of steel and fabric-reinforced rubber. Since lateral stiffeners are not employed, the drive force is transmitted by means of V-groove-type drive wheels which engage raised V-belt-like rails on the track. This light flexible type of track has many desirable characteristics for achieving high flotation for light vehicles and cargo trailers. It is not used on combat-type tracked vehicles because of its strength limitations.\n10-37.3.2 Rubber Band Track This term applies to the type of reinforced rubber track used in the American half-track vehicles of the 1930's and World War II. Lateral stiffness is obtained in this track by means of rigid cross members vulcanized into the rubber. The driving force is transmitted by the sprocket through these rigid cross members. In order to restrict the twisting of the track along its longitudinal axis, the track guide members are interlocked (see Figure 10-52).\n10-37.3.3 Band-Block Track The band-block track has either rubber blocks\nor metal track bars bolted or riveted to the flexible,\n10-68" + ] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure27.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure27.5-1.png", + "caption": "FIGURE 27.5. Definition of distance d.", + "texts": [ + " driver uses a reference a point close to the front end of the vehicle, as when driving in the fog looking at the curb, while the oscillations disappear when the reference point is far in front of the vehicle. A simple way to incorporate a kind of predictive behavior into the model is that of using as error not the difference between the desired and the actual value of the yaw angle, but the distance d between a point on the vehicle x-axis at a given distance L in front of the vehicle and the required trajectory (distance d in Fig. 27.5a). With simple computations and assuming that angle \u03c8 \u2212\u03c81 is small, such a distance can be approximated as d = L ( \u03c8 \u2212 \u03c81 + y L ) , (27.23) where y is the lateral displacement of the vehicle, i.e. the integral of the lateral velocity v. If the speed of the vehicle is constant, with the usual linearization, it coincides with the integral of \u03b2, multiplied by V . Angle \u03c81 is the angle between the X-axis and a line passing through two points of the trajectory at a distance L; it may be easily computed from the shape of the trajectory" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-47-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-47-1.png", + "caption": "Figure 10-47. Single-Pin Shoe Assembly (T91E3 Track)", + "texts": [ + " A grouser (chevron) is a raised segment on the tread surface of the block, which affords increased traction over a smooth tread surface. In the T91B3 track the detachable pad functions as a grouser. All current tracks are rubber-bushed with 0.187-inch-thick, doughnut-type bushings. In the T91E3 single-pin track the basic metalrubber structure is called the body. When bushings are added, the assembly is known as a link and is comparable to the link of the double-pin rack. The link, pin, nuts and washers (Figure 10-47) make up the shoe assembly. Center guides are either bolted to or integral with the top of the body (T91E3 track), or attached by caps to the pins (T96 and T84B1 tracks). In the latter case the capped guide not only functions as a track retaining component but as an additional connecting unit. Outer guides are sometimes incorporated at the extremities of the links, and are made integral with end connectors of double-pin tracks and integral with the body or link of singlepin tracks. Binocular frames arc metal tubular units with webbed ends, and are designed to contain the bushings and pins of double-pin tracks" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002698_12235_FULLTEXT01.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002698_12235_FULLTEXT01.pdf-Figure6-1.png", + "caption": "Figure 6. Effective penetration for T-butt welds.", + "texts": [ + " If the plates are controlled or brought into force by a rigid structure the weld can be considered centrically loaded. The design resistance of a T-butt joint, consisting of a pair of partial penetration butt welds reinforced by superimposed fillet welds, may be determined as for a full penetration butt weld if the total nominal throat thickness, exclusive of the un-welded gap, is not less than the thickness t of the part forming the stem of the tee joint, provided that the un-welded gap is not more than (t / 5) or 3 mm, whichever is less, see figure 6. The design resistance of a T-butt joint which does not meet the requirements should be determined using the method for a fillet weld or a deep penetration fillet weld, depending on the amount of penetration. The throat thickness should be determined in conformity with the provisions for both fillet welds and partial penetration butt welds. 2.4. Fillet welds The rules for fillet welds are valid if the angle between the welded plates is 60\u00b0 \u2264 \u03b1 \u2264 120\u00b0. If the angle is < 60\u00b0 then the fillet weld should be designed as partial penetrated butt weld" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000946_i_pdfs_ADA299658.pdf-Figure5-19-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000946_i_pdfs_ADA299658.pdf-Figure5-19-1.png", + "caption": "Figure 5-19: Photograph of the Actuator test rig", + "texts": [], + "surrounding_texts": [ + "The motor board contains a Motorola 6811 micro-controller, on which the control code runs. The 6811 has 4 analogue to digital converters, which are used to sample the sensor readings. The control loop is set to run at 1kHz. The board also contains hardware to read the encoder on the motor, a PWM generating circuit, and a H bridge to provide power to the motor. There is a differentially driven communication bus to the Motorola 68332 processor. Code for the 6811 is hand coded in assemblylanguage, and then down-loaded from the serial line of the Macintosh PC. The motor board essentially contains all that is need to control the motor. The 68332 is used for higher level processing. It communicates with the motor board at up to 400Hz, sending gains and set-points for the control loop, and receiving data. The processor runs L, a subset of Common Lisp, written by Rodney Brooks at MIT [6]. The front end of the 68332 is a Macintosh PC, where the data from the actuator can be displayed and analysed. 56 CHAPTERS. ACTUATOR DESIGN 5.7 Control The control loop implemented on the 6811 is similar to that detailed in Chapter 3. A block diagram showing all the systems is included in Figure 5-17.. There are essentially five parts in the diagram, the sensor differentiation part, the PID servo on desired torque, the feedforward terms for desired torque and acceleration of the output shaft, and the feedforward model of the motor. Some comments about the block diagram: \u2022 The A/D converter on the 6811 is only 8 bits, so in order to reduce the errors from differentiating small signals in software, the analogue sensor readings were differentiated using an analogue circuit. The encoder reading is 16 bits, and changes enough in normal use to allow differentiation in software. To help this, the effective sampling frequency for the encoder was reduced to 250Hz. \u2022 The feedforward model described in section 3.3 was implemented apart from the term which included the second differential of the desired force. This was because of the difficulties of differentiating small fixed numbers in software. The encoder velocity was calculated by differencing the encoder readings. This was used with the differentiated strain gauge signal to calculate the acceleration of the output shaft 9t. The parameter \"Fgain\" is a gain parameter corresponding to the amount of feedforward used (Kfj in figure 3-5). \u2022 The readings for the strain gauges were converted to 16 bits for the servo loop calculations, and 16 bit gains were used. The output of the servo loop is a desired current, an 8 bit number. This is the input to the feedforward motor model, which produces a PWM duty cycle command (8 bits) and a direction (1 bit) which are applied to the motor. The 6811 carries out fixed point arithmetic, which is why there are so many \"divide by 256\" terms in the block diagram'. \u2022 The motor is driven by an H-bridge, using PWM at 48V, and 31.25kHz. A simple feedforward model of the motor was used to calculate the correct voltage to apply to ensure that the motor current (and so the torque) followed that commanded by the control system. The 6811 was not fast enough to run a separate current feedback loop as well as the torque control. A full feedforward model would include terms to compensate for the motor resistance, inductance and back emf (see Figure 5-18), however only terms for the resistance and the back emf were implemented. 5.7. CONTROL 16 10\u22126 \u2217 I4\u00d74, 4 \u2264 t \u2264 16, R = { 10\u22122 \u2217 I4\u00d74, t < 4s, t > 16 2\u00d7 10\u22124 \u2217 I4\u00d74 4 \u2264 t \u2264 16, (23) The initial value of noise covariances are set as Q\u0302 = 10\u221210, and R = 10\u22124. Results of the estimation of states of the system are given in Fig. 12. The estimation error and mean square error (MSE) of the estimation, which are given in Fig. 13, and Tab. 11, show that the proposed filter is an acceptable solution and can be applied to different nonlinear systems while employing the proposed conditions. To obtain an idea of a realistic behaviour of the developed method, it is applied on a practical servo-hydraulic system. The system are shown in Fig. 14 is located at the Laboratory of Intelligent Machines at LUT University. The practical data is collected from the system. The proposed method is applied on it, and results are presented in Fig. 15. IV. ANALYSIS AND DISCUSSION The analysis should be separated into two different parts. First, it is necessary to discuss the proposed fuzzy adaptive evolutionary algorithm. The proposed algorithm was developed by implementing fuzzy logic to determine the updating factor for the new candidate solutions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001006_f_version_1529920169-Figure20-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001006_f_version_1529920169-Figure20-1.png", + "caption": "Figure 20. A planned route for the robot.", + "texts": [ + " Suppose that the robot initially rests at point-a and starts a sequence of forward motions. That is, striding three steps toward point-b; turning 45o counterclockwise; striding three steps toward point-c; turning 45\u00b0 counterclockwise; striding three steps toward point-d. Then, it manages a turn with 135o clockwise and initiates a sequence of backward motions. That is, striding three steps toward point-e; turning 45o counterclockwise; striding three steps toward point-f; turning 90o counterclockwise; striding three steps toward point-a; turning 135o clockwise. Figure 20. A planned route for the robot. Based on Equation (8) with parameters H = 133 mm, L = 40 mm, D = 45 mm, the simulation showed satisfactory results. The top view of the central pattern as shown in Figure 21 agreed with the planned route. The isometric view of the central pattern as shown in Figure 22 reveals the nature of the motion performed by this robot, where each ripple corresponds to a step. The center of mass fluctuated between 88 mm (=H \u2212 D) and 128 mm (=H \u2013 D + L) for every step within step size equal to 80 mm (=2 \u00d7 L). Figure 19. Graphical user interface. A planned route for the robot to move as shown in Figure 20 is illustrated to justify the formula established by the previous section. Suppose that the robot initially rests at point-a and starts a sequence of forward motions. That is, striding three steps toward point-b; turning 45o counterclockwise; striding three steps toward point-c; turning 45\u25e6 counterclockwise; striding three steps toward point-d. Then, it manages a turn with 135o clockwise and initiates a sequence of backward motions. That is, striding three steps toward point-e; turning 45o counterclockwise; striding three steps toward point-f; turning 90o counterclockwise; striding three steps toward point-a; turning 135o clockwise", + " Suppose that the robot initially rests at point-a and starts a sequence of forward motions. That is, striding three steps toward point-b; turning 45o counterclockwise; striding three steps toward point-c; turning 45\u00b0 counterclockwise; striding three steps toward point-d. Then, it manages a turn with 135o clockwise and initiates a sequence of backward motions. That is, striding three steps toward point-e; turning 45o counterclockwise; striding three steps toward point-f; turning 90o counterclockwise; striding three steps toward point-a; turning 135o clockwise. Figure 20. A planned route for the robot. Based on Equation (8) with parameters H = 133 mm, L = 40 mm, D = 45 mm, the simulation showed satisfactory results. The top view of the central pattern as shown in Figure 21 agreed with the planned route. The isometric view of the central pattern as shown in Figure 22 reveals the nature of the motion performed by this robot, where each ripple corresponds to a step. The center of mass fluctuated between 88 mm (=H \u2212 D) and 128 mm (=H \u2013 D + L) for every step within step size equal to 80 mm (=2 \u00d7 L)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002414_f_version_1598603470-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002414_f_version_1598603470-Figure13-1.png", + "caption": "Figure 13. Four solutions to the inverse displacement analysis for each pattern: (a) negative/positive, (b) positive/positive, (c) negative/negative, and (d) positive/negative. (These results depended on the values of angles \u03b8C and \u03b8D).", + "texts": [ + " If the case of chain ACE is considered, the detailed equations used to determine the angle of joints A and C can be described as follows: \u03b8CAE = cos\u22121 ( l2 AC + d2 AE \u2212 l2 CE 2lACdAE ) , \u03b8ACE = cos\u22121 ( lAC 2 + lCE 2 \u2212 d2 AE 2lACdCE ) (11) dAE = \u2016E\u2212A\u2016 , \u03b8\u03b1 = atan2(ey \u2212 ay, ex \u2212 ax) (12) \u03b8A = \u03b8\u03b1 + \u03b8CAE, \u03b8C = \u03b8ACE \u2212 \u03c0 (13) where lAC, dAE, lCE, \u03b8\u03b1, \u03b8A, \u03b8C, \u03b8CAE, and \u03b8ACE are the link length of AC, distance between joints A and E, link length of CE, orientation angles of AE from the x axis, angle of joint A, angle of joint C, angle of CAE, and angle of ACE, respectively. Because chains ACE and BDF have the same kinematic structures, each joint angle of chain BDF can be derived using the same method. Figure 12 shows the procedure of the inverse displacement analysis of the PMG. In the results of the displacement analysis, there are four types of solution, as shown in Figure 13. Each solution is classified by the angle values of \u03b8C and \u03b8D. Considering rehabilitation, the users\u2019 hands will be located inside the chain ACEBDF. To prevent collisions with the hands, solution (a) is considered suitable for the application in this study. If the OG is projected on the y\u2032z\u2032 plane of the P\u2032-x\u2032y\u2032z\u2032 coordinate system, it can be considered to be a four-bar linkage even though an offset was adopted in the proposed mechanism. Figure 14 shows a diagram of the OG in the plane. The model of the OG can be considered to be a four-bar linkage" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000541_f_version_1559303731-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000541_f_version_1559303731-Figure11-1.png", + "caption": "Figure 11. Traction margin T\u00b5 and contact forces on a curved surface against thickness t and angular position \u03d1gravity along the curved path. (a) Traction margin; contact force for (b) the wheels in P0,r and (c) the skid in P1,r.", + "texts": [ + " In the following, the results of traction margin T\u00b5 are presented in different combinations of parameters, namely, t, the mass of the master robot mm, the orientation of the gravity vector \u03d1, and slope angle \u03b3 of the parking structure. The first aspect that needs to be addressed is the one related to the curved portion of the support sheet. Indeed, as can be seen from Figure 2, the robot travels from an upright to an upside-down configuration by traveling along a cylindrical polycarbonate sheet. The chart in Figure 11 shows how the traction margin behaves for different sheet thicknesses t along the path around the cylinder, represented by gravity vector orientation \u03d1. For design purposes, the selection of t can be done by making sure that Equation (20) is satisfied along the entire curved trajectory, i.e., when \u2212\u03c0/2 \u2264 \u03d1 \u2264 \u03c0/2; this guarantees that the robot operates correctly on the curved sheet. Curvature \u03c1 of the cylindrical surface being the second main parameter, we can see the behavior of T\u00b5 against it in Figure 12 along with the contact forces", + " Ceiling operation, i.e., when the robot is overturned, depends on same Conditions (20); however, in this case, the support surface is planar and horizontal: \u03d1 = \u03c0/2. It is worth noting that the worst-case scenario is indeed when the surface is horizontal as opposed to otherwise oriented; in Figure 13, the traction margin is shown along with the contact forces: it can be seen that, for a fixed mass of mr = 0.200 kg, contact forces are lower than those existing at \u03d1 = 0 at the same thickness t, as seen in Figure 11. This observation is made assuming that the influence of curvature is negligible; in fact, as previously discussed, the curvature has a detrimental effect, which strengthens the thesis. The last fundamental operating scenario is that of parking (Phases D and E). These phases are reversible, i.e., the system can transition F \u2212\u2192 E \u2212\u2192 D \u2212\u2192 C (engaging with the follower cart) similarly to C \u2212\u2192 D \u2212\u2192 E \u2212\u2192 F (parking); note that a certain hysteresis exists that stems from the friction of the follower cart, although this can safely be neglected" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003798_india.org_img_87.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003798_india.org_img_87.pdf-Figure3-1.png", + "caption": "Figure 3: Proposed Concept Model \u2013 01", + "texts": [], + "surrounding_texts": [ + "Traction is an essential component of an outdoor mobile robot. A suitable design can result in higher optimal performances. The design of traction mechanism varies from one model to another according to applications and requirement. It has been observed that use of arm or leg reduces traction and limits mobility, so any form of leg/arm is discarded since mobility is one of the primary concerns of terrain adaptability. Continuous tracks enjoy a lot of advantages over wheels. Compared with wheels tracks have higher performance, optimized traction system, better power efficiency and lower ground impact. Two different kinds of stresses develop under a rigid wheel. One is due to the weight of the vehicle and the other is due to the shear stresses developed by driving moment Mg Bekker and Janosi developed formulas for normal and shearing interaction respectively which were developed from soil test instruments. Bekker\u2019s formulas applications were restricted but Janosi\u2019s shearing interaction models have been used universally [1]. F A K sl sl K t max{ [ exp ( )]}1 1 [N] (7) Here: A = the ground contact area for a tracked vehicle [m2], l = the length of the area [m], max = the maximum value of the shear stress [N/m] cmax (8) c = the internal cohesion of the soil (N/m 2 ), = coefficient of internal soil friction, = normal soil stress under a wheel (N/m 2 ), K = shape factor of the shear diagram [m], s = slip Tractive forces for both the wheel and track-belt configurations were calculated. It was revealed from the above equations that increase in the ground contact area and track length or both resulted in an increase in the tractive force. The more the tractive force less is the chance of slipping. It has been already noted that track belt configuration has several advantages over the wheeled configuration in terms of enhanced bearing area, positive traction and uniform load distribution over the soil, spot turning etc. The passive compliance difference between wheeled and tracked configuration is shown in Fig. (2). The proposed system has to explore mostly in the outdoor rugged rough terrains, marshy lands, sandy area, rocky or hilly areas or areas with larger undulations. For this purpose larger ground clearance is necessary along with obstacle over ridding capability. Obstacle over-riding is somehow related with the approach angle. Based on the above requirements the following configurations using links, pulleys and tracked belts have been designed and analyzed. The analysis has been presented in brief below. First of all, the belt lengths readily available in the market were taken into account and then the four models were designed with different arm lengths and pulley diameter, keeping the payload same. As it has to move over rough terrain change of configuration is imperative. The first concept model as shown in Fig. (3) uses a rigid Y-shaped link with three pulleys of same size (outside diameter is 381 mm) for each side. All the pulleys are identical. The link can rotate about a hinged point placed at the middle of the link to generate a new configuration. A tracked belt has been used for traction and transmission of power to all the pulleys. The belt lengths for both these configurations are same as mention above. The maximum ground clearance is only 67 mm. However the major disadvantage of this configuration is that a huge amount of power will be required to rotate the link about its hinge point. The overall maximum length of the system will be 863.45 mm. All dimensions in the schematics are in millimeter. The second concept model as shown Fig. (4) differs from the first one in terms of using the third pulley of larger diameter (approximately 610 mm). Otherwise it uses similar Y-shaped link with three pulleys wrapped with double sided tracked belt. The belt length has increased to 4377 mm. This length is constant for both the configurations. The maximum overall length of the system is around 1805 mm. The maximum ground clearance that can be obtained is around 124 mm which is higher than the first one. However the disadvantage is same as before i.e. it needs huge power to rotate the link and it may not be possible to rotate the link while the system is in motion. The third concept model use two rigid links rather than a single link. The Y-shaped configuration is formed by a straight link another shorter link hinged at angle with the straight one. The shorter link is rotated to generate different configuration for over-riding on obstacles of different size and shape. Here two pulleys are identical (diameter is 190.99 mm) and third one is larger in diameter (302.76 mm). The belt length has to be kept constant in spite of the rotation of the shorter link as well as two different configurations have to be generated. Fig. (5) shows two different configurations and the corresponding belt lengths are 2479.8 mm and 2468.9 mm. This negligible difference will be compensated by adjusting the tension of the belt. Here the maximum overall length of the system is approximately 950 mm. The maximum ground clearance is around 250 mm. Approach angle has been provided for the ease of riding over any obstacle. The fourth concept model uses two flexible links to form the Y-shape for better overriding capability. Here the straight link as well as the shorter (branch) link is telescopic in nature. This will help the system to keep the belt length constant as well as obtain different approach angles for over-riding the obstacles. As shown in Fig. (6) the length of the straight link changes from 650 mm to 750 mm (stroke is 100 mm) whereas the length of the short link changes from 240 mm to 325 mm (stroke is 85 mm). The dimensions of the pulleys are same as in the concept model 03. In this model only the larger pulley has been used to approach during over-riding obstacles in comparison to the concept model 03. The maximum overall length is 881 mm and the ground clearance is constant at around 200 mm." + ] + }, + { + "image_filename": "designv7_3_0001002_0.1145_358628.358643-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001002_0.1145_358628.358643-Figure7-1.png", + "caption": "Fig. 7. Use o f a Div ide-and-Conquer Strategy for Comput ing an Integral Property I o f a Solid S Represented in CSG.", + "texts": [ + " A CSG representation of a solid is a tree whose nonterminal nodes represent operators and whose leaves represent primitive solids. A natural method for computing integral properties of solids represented via CSG exploits a \"divide-andconquer\" strategy by applying recursively the formulas: (12b) (The starred operators are slighly modified--regularized-versions of the conventional set operators [18]). Observe that the \"primitive problem\" one must solve is that of evaluating an integral over the intersection of an arbitrary number of primitive solids. As the example in Fig. 7 shows, the number of primitive problems grows swiftly (exponentially, in a worst case) and the primitive problems are not of homogeneous complexity. Thus it is easy to generate examples in which everything interacts with everything else and the computational load is enormous. Typical mechanical parts do not exhibit this \"pathological\" behavior, however, and most of the primitive problems yield null results. Nevertheless, the limited experimental evidence obtained by testing a program written by Check and Requicha at the University of Rochester indicates that the number of non-null terms generated may be too large for the method to be computationally attractive for reasonably general domains of solids" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure30.7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure30.7-1.png", + "caption": "FIGURE 30.7. Geared system: Sketch of the (a) actual system and (b) equivalent system; (c) planetary gear train. Sketch of the system and notation.", + "texts": [ + " The driveline, including shafts, gear wheels, joints and other elements such as the clutch with related damper springs, may be modelled as a lumped parameters system (made by massless shafts where the elastic properties of the system are concentrated) with lumped masses modelling its inertial properties. The damping of the system may be neglected altogether, or modelled by introducing suitable viscous dampers in parallel to the springs modelling the various parts of the shaft and joints. gear, the configuration of the driveline is fixed. There is then no difficulty in building a simple mathematical model of the entire system. Nor does the fact that the various elements of the driveline rotate at different speeds cause problems. Consider the system sketched in Fig. 30.7a, in which the two shafts are linked by a pair of gear wheels, with transmission ratio \u03c4 . For the study of the torsional vibrations of the system, it is possible to replace the system with a suitable equivalent , in which one of the two shafts is replaced by an expansion of the other (Fig. 30.7b). Assuming as well that the deformation of gear wheels is negligible, the equivalent rotations \u03c6\u2217 i may be obtained from the actual rotations \u03c6i simply by dividing the latter by the transmission ratio \u03c4 = \u03a92/\u03a91, \u03c6\u2217 i = \u03c6i \u03c4 . (30.30) The kinetic energy of the ith flywheel, whose moment of inertia is Ji, and the elastic potential energy of the ith span of the shaft are, respectively, 30.3 Driveline 597 T = 1 2Ji\u03c6\u0307 2 i = 1 2J\u2217 i \u03c6\u0307 \u22172 i , U = 1 2ki ( \u03c62 i+1 \u2212 \u03c62 i ) = 1 2k\u2217 i ( \u03c6\u22172 i+1 \u2212 \u03c6\u22172 i ) , (30", + "33) dampers in parallel to the springs, the damping coefficient must be multiplied by the square of the gear ratio. If the system includes a planetary gear train, the computation can be performed without difficulties. The equivalent stiffness can be computed simply from the overall transmission ratio. The total kinetic energy of the rotating parts must be taken into account when computing the equivalent inertia. The angular velocities of the central gear \u03a91, of the ring gear \u03a92, of the revolving carrier \u03a9i, and of the intermediate pinions \u03a9p of the planetary gear shown in Figure 30.7c are linked by the equation \u03a91 \u2212 \u03a9i \u03a92 \u2212 \u03a9i = \u2212r2 r1 , \u03a9p = (\u03a91 \u2212 \u03a9i) r1 rp \u2212 \u03a9i. (30.34) The equivalent moment of inertia of the system made of the internal gear, with moment of inertia J1, the ring gear, with moment of inertia J2, the revolving carrier, with moment of inertia Ji, and n intermediate pinions, each with mass mp and moment of inertia Jp, referred to the shaft of the internal gear is Jeq = J1 + J2 ( \u03a92 \u03a91 )2 + (Ji + nmpr 2 i ) ( \u03a9i \u03a91 )2 + nJp ( \u03a9p \u03a91 )2 . (30.35) to introduce two separate degrees of freedom for the two meshing gear wheels into the model, modeled as two different inertias, and to introduce a shaft between them whose compliance simulates the compliance of the transmission" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004197__tsotr2015_01019.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004197__tsotr2015_01019.pdf-Figure4-1.png", + "caption": "Figure 4. Wing edge design layouts a) variant 1; b) variant 2: c) variant 3.", + "texts": [ + " It is visible that the most loaded area is the edge radius limited by 10 mm density from the critical point. The maximal values for the heat flux density constituted 260 000, 1 430 000 and 4 720 000 W/m2 for the flow speed of 1000, 2000 and 3000 m/s correspondingly. In hypersonic aircraft leading edges high-temperature ceramics (HTC) [14], ceramic matrix composite materials (CMC) [15], or high-porousity quartz ceramics [16] can be used [2]. A number of leading edge design variants were developed for these materials (Fig. 4). Their external profile corresponded to the gas-dynamics model. 01019-p.3 In order to analyze the thermal state of the design variants, combined heat transfer process was simulated. All the materials were assumed to be void-free, homogeneous, possessing temperature dependent density, heat capacity and heat conductivity. All the surfaces were assumed to be diffusely radiating grey. The emissivity coefficient was specified as non-temperature dependent. The thermal contact at the materials interface was assumed to be ideal", + " The mathematical model of the process constituted a system of the three-dimensional non-steady non-linear heat conductivity equation and the radiative heat transfer equation for a system of diffusegrey surface bodies [17]. It was assumed that the outer surface is exposed to the heat fluxes obtained from the gas dynamics modelling problem (Fig. 3), with the environment temperature equaling 213\u00b0 K. The simulation was performed in the ANSYS Transient Thermal\u00b0 16.0 software package [13]. The series of calculations for each variant provided temperature fields. The first variant (Fig. 4a) was based on the CMC shell reinforced with heat-resistant aircraft-grade steel elements [16]. The casing wall was 4 mm thick, the load-bearing elements were positioned at 140 and 320 mm distance from the critical point. The position of the hottest area corresponds to the position of the applied heat flux maximum \u2013 approximately 10 mm from the critical point. In the case of 2900 m/s flow the temperature of the front load-bearing element reached the limit of the steel temperature operating range. For 3000 m/s speed, the temperatures in the critical points and loadbearing elements exceed maximum values for the materials used. The second variant (Fig. 4b) was also based on the CMC shell. But in order to block thermal radiation from the shell surface inside the structure, thermal protection screens from high-porousity quartz ceramics were positioned in the grooves of the front load-bearing element. For 2000m/s flow speed the front load-bearing element temperature was close to the maximally acceptable. For 3000 m/s speed, the temperature of several elements exceeded the acceptable values. In the third variant (Fig. 4c) an additional HTC cap was installed in the most heat loaded area of the wing edge. The front load-bearing element was made out of CMC and the rear element from the heat resistant aircraftgrade steel. Apart of that an additional thermal protection screen was installed into the groove of the rear loadbearing element. At 3000 m/c flow none of the elements had the temperature higher than the acceptable values. The temperature field for the third design variant of the wing edge for 2000 m/c flow speed is presented in Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure6-14-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure6-14-1.png", + "caption": "Figure 6-14. Aviation-Type \u00dfo/imorfini Track", + "texts": [ + " The track is tensioned by various mechanical and hydraulic means to about 1000 to 1800 pounds (for a vehicle of about 2,200 lb gross weight), and the inflation pressure varies between 10 and 28 psi 6-9 AMCP 706-356 depending upon the operational environment. The pneumatic track is molded of rubber and fabric, is of tubeless construction, and is reinforced with steel wires (in the sidewalls of the aviation type track) or a flexible, inextensible belt (in the tractor type track) imbedded longitudinally in the track walls to absorb the track tension and to improve the track's lateral stability. The aviation-type track (Figure 6-14) is smooth on both surfaces, i.e., on its tread surface and on the surface which contacts the driving and idler wheels. In addition, the surface which contacts the wheels is lubricated. The tractor-type track is raised cleats or lugs molded onto its tread surface. The inner or wheel- contacting surface is molded with deep, transverse grooves Avhich mesh with sprocket-like lugs across the concave face of the driving wheel (Figure 6-15). This results in a positive track drive. The wheel-contacting surfaces of the tractor-type track are not lubricated" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000759__106414_TLA_0311.pdf-Figure4.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000759__106414_TLA_0311.pdf-Figure4.5-1.png", + "caption": "FIGURE 4.5: CAD drawings of dummy fingers for force and torque measurements (Left) and motion capture (Right). Dimensions for the fingers are presented in Table 4.4. The models are available online at the Thingiverse website [74].", + "texts": [ + " Although measuring soft actuators\u2019 free motion and constrained force output on a test rig can be used to compare different actuators to each other, to get a realistic view of the actuators\u2019 performance, they should be attached to a finger. Furthermore, if the actuators extend also in length, accurate tip force measurement becomes difficult due to the deformation. However, accurate measurement of motion trajectories and torques of a human finger is challenging due to the soft tissues that cover the underlying skeletal structure, and the possibility of human influence on the results. Thus, we designed and manufactured an anthropomorphic dummy finger (Figure 4.5) that worked as a test bench for measuring how the reinforcements affected the coupled motion and joint angles, and the torques that the actuators could apply to the finger joints. The MCP joint was a 2-DoF ball joint, and the IP joints were 1-DoF pin joints. As with the actuators, the dummy finger\u2019s dimensions (Table 4.4) were based on the collaborating patient\u2019s index finger. actuators Two versions of the finger were made, one for force and torque measurements and one for motion capture (Figure 4.5). The fingers were 3D printed from PLA. The one for torque measurements had holes through the IP joint centers for wire attachment, while 3-mm reflective markers were attached to the one for motion capture. CAD files and further details for both dummy fingers are available online at the Thingiverse website [74]. For evaluating the prototypes\u2019 response, we connected them to the dummy finger and measured the finger\u2019s motion with a motion capture system. The motion capture measurements were made in 1D, meaning that only one camera for each plane of motion was used" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003694_f_version_1532416988-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003694_f_version_1532416988-Figure13-1.png", + "caption": "Figure 13. Overall configuration of the slave robot.", + "texts": [ + " In addition, an encoder (E40H; Autonics, Incheon, Korea) and an IMU sensor (MPU-9250, InvenSense, Sunnyvale, CA, USA) are used to measure position information; a 6-axis force/torque sensor and a 1-DOF torque sensor (SDS-100; Senstech Corp, Busan, Korea) are used for torque and force measurement. 4.1. Integration of Haptic Master and Slave Robot Fig re 12. hotogra h of the ha tic aster syste feat ring cl tches an brakes. Materials 2018, 11, 1268 12 of 17 As mentioned earlier, the slave robot implements the surgical command transferred from the master. The mechanism of the 6-DOF slave robot is proposed as shown in Figure 13. The proposed slave robot consists of three robot arms, servomotors, and a surgical instrument. Because the surgical instrument is inserted into a small incision, the instrument is attached to the end point of the third robot arm. In addition, a surgical tool such as forceps or a knife is placed at the opposite end of the instrument. As the wire and motor actuator are connected with the surgical tool, the surgical tool can rotate in three directions, i.e., rolling, pitching, and spinning. Each robot arm can rotate using the servomotor, and the end position of the third arm moves along the X, Y, and Z axes", + " In addition, the rotation information of the haptic master handle along the pitching, rolling, and spinning directions is directly transferred to the surgical tool part of the slave robot. Based on the transferred rotation command, the surgical tool is rotated using the wire actuator. Please refer to the details about the transformation in [31,32]. The rotational information of the handle is measured using the inertial measurement unit (MPU-9250). Materials 2018, 11, x FOR PEER REVIEW 12 of 17 As mentioned earlier, the slave robot implements the surgical command transferred from the master. The mech nism of the 6-DOF slave robot is roposed as shown in Figure 13. The proposed slave robot consists of three robot arms, servomotors, and a surgical instrument. Because the surgical instrument is inserted into a small incision, the instrument is attached to the end point of the third robot arm. In addition, a surgical tool such as forceps or a knife is placed at the opposite end of the instrument. As the wire and motor actuator are connected with the surgical tool, the surgical tool can rotate in three directions, i.e., rolling, pitching, and spinning. Each robot arm can rotate using the servomotor, and the end position of the third arm moves along the X, Y, and Z axes" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001658_f_version_1705566273-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001658_f_version_1705566273-Figure12-1.png", + "caption": "Figure 12. The stability tetrahedron is formed by the contact points of the wheels and the center of inertia of the robot.", + "texts": [ + " However, checking the stability under dynamic conditions would be an interesting extension of this work. The tip-over stability margin was computed with a simple static analysis, considering the center of inertia, the angle of the contact plane formed by the three contact points, and the reaction forces at the wheels. In the case of the three-wheeled robot, we can create tip-over planes by joining the contact point of two wheels with the center of inertia of the robot, forming a tetrahedron; see Figure 12. In order to ensure static stability, the axis of the weight force, located at the center of inertia, must fall within the tetrahedron in order to determine whether the robot will roll over. It is easy to see that, for the offset-differential robot, unless the load is perfectly centered at the vertical rotation axis, lateral stability must be checked during the motion planning of the robot, even in smooth, horizontal terrain. The angle of the caster wheel needs to be known in order to perform this check" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000668_f_version_1574234693-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000668_f_version_1574234693-Figure11-1.png", + "caption": "Figure 11. Gazebo simulated world used for the experiments. We use an extended version of the world originally created by Speck et al. [3]. Waypoints (e.g., w1) that are used during the different experiments have been indicated on the map. For all experiments there are also waypoints either side of doorways.", + "texts": [ + " Through simulated experiments we aim to demonstrate (i) how much representing all devices as a single \u201cremote\u201d device has reduced the number of calls from the TFD/M planner to the Capability Checker; (ii) our framework\u2019s ability to trigger replanning when a device becomes unavailable, (iii) the effect increasing the number of objects in the environment has on the planning time and (iv) the effect increasing the number of layers in the PDDL hierarchy has on the planning time. All these experiments use an environment simulated with Gazebo, this is shown in Figure 11. The State Estimators and Action Executors used are described in Table 1 and Appendix A, respectively; the goal the goal_creator sets is specific to each experiment. Each subsection describes the experiment set-up, followed by the results. In this section, experimental results are presented to show how including all remote devices as separate objects in the PDDL problem compares to representing the remote devices as a single object. The number of calls from the TFD/M planner to the capability checking module, for a varying number of devices, are provided in Table 2", + ", number of primitive actions) and the time spent planning are discussed. All experiments were ran on a virtual machine with 9GB of RAM and an Intel i7 2.9GHz CPU. The scenario also demonstrates the applicability of our designed hierarchy to a different situation, that is, a smart office environment. Further, these experiments demonstrate that our framework is able to monitor both hierarchical and non-hierarchical plans. 8.2.1. Set-Up A smart office environment has two floors with identical floor plans, as shown in Figure 11. Each floor is equipped with an IoT coffee machine, which is located at waypoint w4. The robot started on the first floor, at location w2 and was tasked with delivering a cup of coffee to a human. Specifically, the robot\u2019s goal was (and (is-full cup1 coffee) (has-object human1 cup1)). This task involved the following high-level steps: (i) getting a cup from location w3 on floor 1, (ii) asking one of the machines to fill the cup and (iii) delivering the cup to a human, located at w5 on the second floor", + " This is also applicable to any state change that may occur, for example, the planned cup being used by another agent, a door being closed, the human moving location and so forth. In order to compare the computational times of planning everything upfront and our hierarchical method, we present the planning times for differing environment complexities. By incrementing the number of floors in our scenario, we are able to increase the complexity of the environment at a steady rate, that is, the total number of object rises linearly. These objects include: waypoints, doors and all IoT devices. As an example, a floor is displayed in Figure 11. 8.3.1. Set-Up For this experiment the robot navigated from its start location (i.e., waypoint1.1_room1.0) to a room on a different floor, which was chosen at random. The plans produced when the randomly selected room is room2.2, for planning everything upfront and for hierarchical planning are shown in Listings 6 and 7, respectively. We selected 3 random different rooms and ran each experiment 5 times; thus, each point on the results graph is the average of 15 runs. The planning everything upfront approach takes, as input, a single domain file containing the actions required to navigate a multi-floor environment, that is, drive_base, request_lift, request_floor and open_door" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-70-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure8-70-1.png", + "caption": "Figure 8-70. Doubly Conjugate Points", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\ntermined mathematically by using the principle that the algebraic summation of the rate moments of the individual suspension units about the spring center is equal to zero, each rate moment being the product of the particular vertical spring rate ~k and its respective longitudinal distance from the spring center x.\nFor tracked vehicles having transverse torsion bar springs, it is customary to longitudinally displace the suspension unit on one side of the vehicle\nrelative to those on the other side. Figure 8-7 shows the offset of typical suspension units for a track-laying vehicle. The spring center on one side of the vehicle is longitudinally offset from that on the opposite side. The longitudinal location of the spring center of the vehicle can be found by passing an axis through the individual centers; the point of intersection of this axis with the longitudinal centerline of the vehicle is the spring center of the basic elastic system.\nSECTION VI PRIMARY VIBRATIONS IN THE LONGITUDINAL VERTICAL PLANE (Ref. 7)\nThe location of the lateral axis of oscillation for a body on resilient supports, e.g., a sprung vehicle, is determined by the combined elastic and inertial behavior of the particular system.\nThe general procedure for determining the location of the lateral axis of oscillation can be explicated by considering the elastic and the inertial influences separately, and then the combined effect. Figure 8-5 is a diagrammatic representation of a typical vehicular suspension system. The analysis will be simplified if the multiple spring system is replaced by an elastically equivalent two spring system. The two spring system is shown in the upper part of Figure 8-8 and is generated by considering the spring rate moments about the spring center C of the lower system.\n8-20 ELASTIC SYSTEM Points such as A and B are called elastically conjugate points. These points are related such that if a vertical force is applied at point A, the body (represented by horizontal axis Y-Y) will rotate about the point B and vice versa. Any pair of points that possess this reciprocal relationship satisfy the equation pq = ab where a, b, p, and q are distances shown in Figure 8-8. Since the dimension q (or p) can be chosen arbitrarily, it follows that there is an infinite number of such pairs of points.\nThe geometrical construction shown in Figure 8-8 enables the pairs of points to be determined graphically. The hyperbola pq = ab \u2014 c2 is drawn relative to the axes XCY. The point \u00dfi corre-\nsponding to B on the hyperbola is projected horizontally to meet the line CZ at Ai. The projection of Ai on the Y axis give.s the point A. It is obvious that as point A approaches point C, point B will approach infinity. Similarly, as point B approaches point C, point A approaches infinity.\n8-21 INERTIAL SYSTEM A similar analysis can be made with respect to dynamically conjugate points. Figure 8-9 shows a\n8-14", + "AMCP 706-356\ntypical vehicular mass system M. A dynamically equivalent mass system can be selected to replace the original system. This second system must possess the same mass, moment of inertia, and position of its mass center as the original mass system. Thus a body consisting of two masses mx and m2 (with mi ~\\- m2 = M) concentrated at points E and F as shown and connected by a weightless bar can be substituted for the original mass provided that the essential dynamical characteristics are the same.\nThe moment of inertia about its mass center of the original mass can be expressed as Mk2. If mir = m2s and m^r2 -j- m2s'2 = Mk2, then rs = k2.\nSince the dimension r(or s) can be chosen arbitrarily, it follows that there is an infinite number of such pairs of points. The geometrical construction shown in Figure 8-9 enables the pairs of dynamically conjugate points to be determined graphically in a manner similar to that used for the elastically conjugate points.\n8-22 COMBINED SYSTEM The elastically conjugate system can be combined with the dynamically conjugate system as shown in Figure 8-10. For a given mass-elastic system, the two hyperbolas will, in general, intersect at one point L. Then the points H and /, which are projected from L, are points which are both elastically and dynamically conjugate and are termed doubly conjugate points.\nIf the position of the mass center G, in Figure 8-10, approaches the spring center C, then the point of intersection of the hyperbolas will move to the right; and when G arrives at C, the point J will be at infinity and the point H will coincide with the common point CG. Under these conditions, and if c2 does not equal k2, the suspended body will oscillate with two independent motions, i.e., translation in the vertical plane, and angular displacement about the point G. The system now acts as if the entire mass is concentrated at H but possesses a moment of inertia about H equal to Mk2.\nAn algebraic method to determine the doubly conjugate points can be presented. By referring to Figures 8-8 and 8-9, the following equations can be written\npq \u2014 ab = c2\nrs = fc2\n(8-33)\n(8-34)\n8-15", + "AMCP 706-356\np = r -\\- x\nq = s \u2014 x\n(8-35)\n(8-36)\nFor a given system the quantities c2, A:2, and x are normally known; and p, q, r and s are to be determined. Substituting for p and q in Equation 8-33 results in\n(r + x) fc2 \\\n(8-37)\nor\nr2 x + r (x2 4- ", + " As the planar equivalent to the Stewart-Gough platform, this mechanism has been investigated by several scientists in terms of direct kinematics [1\u20138,32], singularities [29\u201331,33\u201335] and control [36\u201338]. In this section, we review the classical method to derive the assembly modes of the general planar 3-RPR parallel mechanism by following the method introduced by Gosselin et al. [1]. In contrast to the classical planar 3-RPR parallel mechanism where the manipulator is illustrated as a triangle, we use the mechanism displayed in Figure 1. However, we show that by using the linear actuators\u2019 lengths, for this parallel mechanism, up to six solutions for the direct kinematics problem, that is, up to six assembly modes, exist. The inverse kinematics of the general planar 3-RPR parallel mechanism can be written as \u03c12 1 = x2 + y2 , (2) \u03c12 2 = (x + l1 cos \u03b3\u2212 c1) 2 + (y + l1 sin \u03b3\u2212 d1) 2 , (3) \u03c12 3 = ( x + (l1 + l2) cos \u03b3\u2212 c2 )2 + ( y + (l1 + l2) sin \u03b3\u2212 d2 )2 . (4) By subtracting Equation (2) from Equation (3) and Equation (2) from Equation (4), we get \u03c12 2 \u2212 \u03c12 1 = Rx + Sy + T , (5) \u03c12 3 \u2212 \u03c12 1 = Ux + Vy + W (6) with R = 2l1 cos \u03b3\u2212 2c1 , S = 2l1 sin \u03b3\u2212 2d1 , T = l2 1 + c2 1 + d2 1 \u2212 2l1(c1 cos \u03b3 + d1 sin \u03b3) , U = 2(l1 + l2) cos \u03b3\u2212 2c2 , V = 2(l1 + l2) sin \u03b3\u2212 2d2 , W = (l1 + l2)2 + c2 2 + d2 2 \u2212 2(l1 + l2)(c2 cos \u03b3 + d2 sin \u03b3) ", + " In this section, we demonstrate that by using the three linear actuators\u2019 orientations, the solution of the direct kinematics problem of the general planar 3-RPR parallel mechanism can be calculated analytically and a maximum of two instead of six assembly modes exist. Here, the elimination method described in Section 2.1 is used where the inverse kinematic equations are used to systematically eliminate unknown variables until a univariate equation is obtained. For the general planar 3-RPR parallel mechanism shown in Figure 1, the inverse kinematics can be rewritten as tan \u03d51\ufe38 \ufe37\ufe37 \ufe38 A = y x , (37) tan \u03d52\ufe38 \ufe37\ufe37 \ufe38 B = y + l1 sin \u03b3\u2212 d1 x + l1 cos \u03b3\u2212 c1 , (38) tan \u03d53\ufe38 \ufe37\ufe37 \ufe38 C = y + (l1 + l2) sin \u03b3\u2212 d2 x + (l1 + l2) cos \u03b3\u2212 c2 , (39) where we will be using the abbreviations A, B and C in the following. The angles \u03d51, \u03d52 and \u03d53 are the three orientation angles of the linear actuators with respect to the base platform\u2019s x-axis and can be obtained, for example, from IMUs that are mounted on the linear actuators. Now, we can rewrite Equation (37): y = Ax , (40) and use it in Equation (39): C = Ax + (l1 + l2) sin \u03b3\u2212 d2 x + (l1 + l2) cos \u03b3\u2212 c2 ", + " Here, we use image processing to optically analyse the actual manipulator platform\u2019s pose, whose joints\u2019 positions are equipped with small red dots for optically tracking their position. The positions of the red dots\u2019 center points are therefore detected, stored and converted into the positions of the manipulator platform\u2019s joints from which the manipulator platform\u2019s pose can be calculated. For the experiments on the general planar 3-RPR parallel mechanism, we use the following parameters for the base and manipulator platform\u2019s joints\u2019 coordinates according to Figure 1: c1 = 170 mm , d1 = 10 mm , l1 = 70 mm , c2 = 280 mm , d2 = \u221220 mm , l2 = 30 mm . (65) The mechanism\u2019s y-axis corresponds to the negative gravity vector of the Earth g. The IMUs are mounted on the linear actuators in the way that their x-axes are always parallel to the mechanism\u2019s z-axis. For static poses, it is therewith possible to obtain the orientation angles \u03d51, \u03d52 and \u03d53 solely from the accelerometer values of the IMU, ay,k and az,k, where \u03d5k,acc = atan 2 ( ak,y, ak,z ) . (66) However, when the manipulator platform moves and, therewith, the linear actuators move too, the accelerometer values do not provide accurate results, leading to faulty pose calculations" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003746_f_version_1666184220-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003746_f_version_1666184220-Figure4-1.png", + "caption": "Figure 4. Composite wheels and elastic shock-absorbing suspension mechanisms: (a) Overall view; (b) Side view; (c) Top view.", + "texts": [ + " In the normal climbing state, there is a small gap between the anti-deflection wheels and the pipeline; when the robot deviates from the pipeline, the anti-deflection wheels contact the pipeline and guide the robot to return to the normal route. Figure 3 shows driving mechanisms of the robot, which provide power for climbing. Two motors are located above the V-shaped wheels and transmit power through multiple gears. The symmetrical layout makes the mass load of the motors evenly distributed on two V-shaped wheels to avoid the sideways shaking of the robot. These two groups of driving mechanisms can rotate flexibly through the rotating joint mechanism. Figure 4 shows the elastic shock-absorbing suspension mechanisms and composite wheels. The composite wheel consists of three small V-shaped wheels, which can rotate flexibly along its own axis. The elastic shock-absorbing suspension mechanism is a four- Figure 2. Mechanical structure of the pipeline-cli bing robot: (a) Overall view; (b) Top view; (c) Side view. Based on double-sided V-shaped wheels and composite wheels, the robot can be clamped on pipelines. The V-shaped wheels have a 150\u25e6 scalloped surface, which is conducive to full contact with the pipelines", + " In the normal climbing stat , ther is a small g p between the anti-deflection whe l and the pipeline; when the robot deviates fro the pipeline, the anti-deflection wheels contact the pipeline and guide the robot to return to the normal route. Figure 3 shows driving mechanisms of the robot, which provide pow r f r climbing. Two motors are located abov the V-shaped wheels and tra smit power through multiple g ars. The symm trical layo t makes th mass load of th otors venly distributed on two V-shaped wheels to avoid the sideways shaking of the robot. These two groups of driving mechanisms can rotate flexibly through the rotating joint mechanism. Figure 3. Driving mechanism of the pipeline-climbing robot. Figure 4 shows the elastic shock-absorbing suspension mechanisms and composite wheels. The composite wheel consists of three small V-shaped wheels, which can rotate flexibly along its own axis. The elastic shock-absorbing suspension mechanism is a four- re 3. Driv ng mechanism of the pipeline-climbing robot. Machines 2022, 10, 874 5 of 17 Figure 4 shows the elastic shock-absorbing suspension mechanisms and composite wheels. The composite wheel consists of three small V-shaped wheels, which can rotate flexibly along its own axis. The elastic shock-absorbing suspension mechanism is a four-bar linkage. The composite wheel position can be adjusted by changing the shape and position of the connecting links. The diagonal joints of the four-bar linkage are tensioned by springs to provide pressing force for the composite wheels. Similarly, two elastic shock-absorbing suspension mechanisms can rotate flexibly through two rotating joint mechanisms", + "3 m/s Obstacle-surmounting height 20 mm Pipeline diameter 50\u2013250 mm Machines 2022, 10, 874 6 of 17 Machines 2022, 10, x FOR PEER REVIEW 5 of 17 bar linkage. The composite wheel position can be adjusted by changing the shape and position of the connecting links. The diagonal joints of the four-bar linkage are tensioned by springs to provide pressing force for the composite wheels. Similarly, two elastic shockabsorbing suspension mechanisms can rotate flexibly through two rotating joint mechanisms. Figure 4. Composite wheels and elastic shock-absorbing suspension mechanisms: (a) Overall view; (b) Side view; (c) Top view. Figure 5 shows the schematic diagram of the robot climbing on curved pipelines of spherical tanks. In order to adapt to curved pipelines, the robot can change the angle between the front and rear wheels through rotating joint mechanisms. The parameters of the pipeline-climbing robot are shown in Table 1. The outer diameter of the V-shaped wheels is 78 mm, and the diameter of the small V-shaped wheels in the composite wheels is 52 mm" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001006_f_version_1529920169-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001006_f_version_1529920169-Figure1-1.png", + "caption": "Figure 1. Visualization of components.", + "texts": [ + " Since stable tripod gaits are generated by mechanism instead of computer, a great amount of computing resources can be released and diverted to engineering applications. In this paper, we will briefly discuss some design issues, elaborate the mechanism of reducing the number of actuators, establish the mathematical model, and introduce the relevant hardware as well as software. Determining how to build a robot is somewhat mundane. Nevertheless, it is sufficiently nontrivial and in fact sophisticated that we must have a design mechanism, select materials, determine component sizes, make engineering drawings as shown in Figure 1, machine all of the parts, and assemble them into a robot as shown in Figure 2, where the size of the robot is about 712 mm \u00d7 641 mm \u00d7 189 mm and the size of its main body is 382 mm \u00d7 222 mm \u00d7 134 mm when six legs are detached. Figure 1 shows that there are only three motors required by this hexapod (i.e., bottom motor, upper motor, and swivel motor). Although ball bearings are better than porous metal bearings in terms of overall performance, they require more space in their housing and more material to construct. In order to achieve a light-weight design, the structure is made of lighter aluminum AT6061T6 and porous metal bearings. Appl. Syst. Innov. 2018, 2, x FOR PEER REVIEW 2 of 15 spinal cord is an autonomous device generating rhythmic behaviors such as locomotion, requiring neither peripheral sensor feedback nor the regulation command from the brain-stem", + " Since stable tripod gaits are generated by mechanism instead of computer, a great amount of computing resources can be released and diverted to engineering applications. In this paper, we will briefly discuss some design issues, elaborate the mechanism of reducing the number of actuators, establish the mathematical model, and introduce the relevant hardware as well as software. Determining how to build a robot is somewhat mundane. Nevertheless, it is sufficiently nontrivial and in fact sophisticated that we must have a design mechanism, select materials, determine component sizes, make engineering drawings as shown in Figure 1, machine all of the parts, and assemble them into a robot as shown in Figure 2, where the size of the robot is about 712 mm \u00d7 641 mm \u00d7 189 mm and the size of its main body is 382 mm \u00d7 222 mm \u00d7 134 mm when six legs are detached. Figure 1 shows that there are only three motors required by this hexapod (i.e., bottom motor, upper motor, and swivel motor). Although ball bearings are better than porous metal bearings in terms of overall performance, they require more space in their housing and more material to construct. In order to achieve a light-weight design, the structure is made of lighter aluminum AT6061T6 and porous metal bearings. Figure 1. Visualization of components. Figure 2. Completed hexapod robot. The servos used in the hobby radio control (RC) market for controlling model airplanes, cars, and boats are also frequently used in robots. The servos that are good for light-weight application Appl. Syst. Innov. 2018, 2, x FOR PEER REVIEW 2 of 15 spinal cord is an autonomous device generating rhythmic behaviors such as locomotion, requiring neither peripheral sensor feedback nor the regulation command from the brain-stem. Hybrid chemes using either fuzzy controllers or neural networks to implem nt bionic control are appealing, and have b en conducted extensively in many articles (e", + " Since stable ripod gaits ar generated by mechanism stead of computer, a gr at amou t of computing resources c n be released and div ted to engineer ng applications. In his paper, we will briefly discus some design issu s, elaborat he m cha ism of reducing the number of actuators, establish the mathematical mod l, and introduce the relevant hardware as well as software. Determining how to build a robot is somewhat mundane. Nevertheless, it is sufficiently nontrivial and in fact sophisticated that we must have a design mechanism, select materials, determine component sizes, make engineering drawings as shown in Figure 1, machine all of the parts, and assemble them into a robot as shown in Figure 2, where the size of the robot is about 712 mm \u00d7 641 mm \u00d7 189 mm and the size of its main body is 382 mm \u00d7 222 mm \u00d7 134 mm when six legs are detached. Figure 1 shows that there are only three motors required by this hexapod (i.e., bottom motor, upper motor, and swivel motor). Although ball bearings are better than porous metal bearings in terms of overall performance, they require more space in their housing and ore material to construct. In order to achieve a light-weight design, the structure is made of lighter aluminum AT6061T6 and porous metal bearings. Figure 2. Completed hexapod robot. The servos used in the hobby radio control (RC) market for controlling model airplanes, cars, and boats are also frequently used in robots" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003638_38496_FULLTEXT02.pdf-Figure5.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003638_38496_FULLTEXT02.pdf-Figure5.5-1.png", + "caption": "Figure 5.5 line of action and offline of action [22]", + "texts": [], + "surrounding_texts": [ + "The misalignment value used in the study was extracted from MASTA where the whole gearbox was modelled. According to MASTA, documentation misalignment is defined in the transverse plane as a displacement along the line of action. If the plane of action is considered, positive misalignment is defined as the gap at the most positive end of the gears in the z direction (in the gears local coordinate system) that there would be if the other ends were just in contact. In this model, the misalignment was negative. In LDP, misalignment also considered in the line of action. According to LDP, negative misalignment in the start or end will add extra material from the flank thus the contact shifts to that side. This misalignment value used is composed of two values that can be expressed in vertical and horizontal axis as in equation (5.3)according to Houser [22] where these two coordinates can be seen. 59 Misalignment along x-direction is called the parallelism error and along ydirection is called skew misalignment. According to Houser, this skew misalignment is far more important compared to the other one. In addition, the misalignment in line of action is calculated with the following formula (5.3) Where and are respectively the two misalignments in x and y direction. In Abaqus, this misalignment was introduced by rotating the gear around perpendicular axis constructed on a reference plane depicting the plane of line of action. One problem encountered introducing the same misalignment in KISSsoft as it was considering the two-different component separately as shown in Figure 5.6. Compared to LDP, inclination in KISSsoft is the parallelism error and deviation error is the skew misalignment. However, there were no instruction or document found how equivalent misalignment in the plane of action was calculated. 60 This uncertainty leads to believe that this could be the reason behind the significant variation in contact stress result for case two from KISSsoft compared to any other software. Master Thesis Stress Analysis Validation for Gear Design 61" + ] + }, + { + "image_filename": "designv7_3_0001147_f_version_1585297185-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001147_f_version_1585297185-Figure11-1.png", + "caption": "Figure 11. Study case: A Franka Emika robot with a PCJ attached at its end-effector executes a three-dimensional (3D) trajectory to get in contact with the patient\u2019s body.", + "texts": [ + " Therefore, the model of the PCJ has been virtually implemented in the robot\u2019s controller. We propose executing a 3D Cartesian trajectory Xd(t) while keeping a fixed orientation, so that the end-effector\u2019s tool is kept upright. This trajectory is typically executed at the beginning of an ultrasound test to contact with the patient\u2019s body. This last one has been represented by a compliant foam. During the execution of the trajectory, along the vertical z-axis, the patient\u2019s body interferes with the desired robot\u2019s trajectory generating a physical contact. Figure 11 illustrates the proposed study case. According to the control law of Equation (4), we defined the PD constant parameters as follows: Kpx = diag{800, 800, 800, 60, 60, 60} N/m and Kdx = diag{56, 56, 56, 15, 15, 15} Ns/m, respectively. The objective function was used to stabilize the internal motion by minimizing the joint velocities, as follows: \u03be = \u22120.1 . qi. We compare the behavior of the robot in two different compliance configurations: For a rigid-body robot case and when using the PCJ. Due to the slow velocities executed on these examinations, around 0" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000139_46226_FULLTEXT01.pdf-Figure23-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000139_46226_FULLTEXT01.pdf-Figure23-1.png", + "caption": "Figure 23. TurtleBot3 Burger components", + "texts": [ + " TurtleBot3 Burger is delevoped by ROBOTIS, which is one of the leading manufacturers of robotic hardware. They specialize in the manufacture of robotic hardware and full platforms for use in all fields of study and industry, as well as educational robotics kits for all ages and skill levels. The TurtleBot3 Burger kit includes a printed easy-to-follow assembly manual that explains step by step how to build the robot correctly. The e-Manual [82] provides both a PDF to download and a set of videos explaining how to assemble it. Figure 23 shows the main components of the TurtleBot3 Burger. The encoder is shown in Figure 23a) is of type XL430-W250, leading the robot to have a maximum velocity of 0.22 m/s. The shape of the Waffle plate leads to a highly versatile structure, allowing the user to customize the robot according to the project needs. OpenCR (Open-source Control module for ROS) is developed for ROS embedded systems to provide completely open-source hardware and software. OpenCR provides digital and analogue input/output pins and supports 12V, 5V, 3.3V power outputs for the different sensors and the Raspberry Pi SBC, where the Raspbian Stretch OS is located" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002287_9159950_09018154.pdf-Figure27-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002287_9159950_09018154.pdf-Figure27-1.png", + "caption": "Fig. 27. Snapshot of hanging mechanism inserted into ceiling hole.", + "texts": [ + " By pressing the plunger into the valley of the index plate, it is possible to correct and hold the turntable turning angle without any sensors. There is also a function to hold the table angle when the robot exits the turntable, which is in the unlocked state. Hence, a turning operation with high angular reproducibility is realized. Fig. 26 shows a functional block diagram of the HanGrawler electrical system. Actuator control and hanging-mechanism position recognition are performed by an 8-b microcontroller (Atmel Co., ATmega2560). We verified the stability of the hanging ability on the perforated metal ceiling plate. Fig. 27 shows the hanging mechanism of the HanGrawler. When this mechanism is locked and a load is applied, the entire mechanism is intended to be located at the center of the hole and to be solidly anchored to the ceiling hole. A regularly locked hanging mechanism has sufficient load durability, and the influence of any external interference is quite low. We evaluated the performance of the linear mobile robot and verified that ceiling movement is possible in combination with mechanical hanging and the crawler mechanism, and that the target load of 50 kg and 0" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004824_f_version_1680588195-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004824_f_version_1680588195-Figure4-1.png", + "caption": "Figure 4. Free body diagram of a gripper jaw. i re 4. i r f a ri er ja .", + "texts": [ + " Actuators 2023, 12, 160 6 of 17 where G(T) is the shear modulus of the SMA spring that is estimated from experiment results in Section 4.1.2. Therefore, when TM \u2264 T \u2264 TA, the axial load at temperature T is expressed as: F(T) = d4G(T) 8D3n \u03b4(T) (3) when the axial displacement of the SMA spring is restricted, the compressed length of the SMA spring is kept as: \u03b4(T) = \u03b4L (4) when TM \u2264 T \u2264 TA, the output force at temperature T can be obtained from (3) and (4) as: F(T) = d4G(T) 8D3n \u03b4L (5) 3.2. Contact Force of Single Gripper Finger Assuming that the gripper is holding an object with a dimension of D, as shown in Figure 4, and is actuated by a pair of SMA springs via tendons, the tendon forces of the second linkage can be expressed as: F2 = F1 \u00d7 cos \u03b81 (6) F4 = F3 \u00d7 cos \u03b81 (7) where F3 denotes the pulling force of Spring 2 at the austenite state, and F1 represents the pulling force of Spring 1 at the martensite state. F1 and F3 can be calculated from Equation (5). The equations denote that G\u2122 represents the shear modulus of SMA spring of SSAs 1, whereas \u03b4L1 signifies the displacement of SSAs 1. Similarly, G(TA) represents the shear modulus of SMA Spring 2 of the SSAs 2, and \u03b4L2 indicates the displacement of the SSAs 2", + " Actuators 2023, 12, 160 7 of 17 Actuators 2023, 12, x FOR PEER REVIEW 7 of 18 Table 1. Parameters of the SMA spring. Parameter Symbol Value Material NiTi-45 Nitinol Spring diameter D 6.5 mm Wire diameter d 0.75 mm Original length Lmin 20 mm Maximum length stretch Lmax 150 mm Number of coils n 21 Elastic modulus at room temperature E 50 GPa Austenite temperature 45\u201350 \u00b0C 3.2. Contact Force of Single Gripper Finger Assuming that the gripper is holding an object with a dimension of D, as shown in Figure 4, and is actuated by a pair of SMA springs via tendons, the tendon forces of the second linkage can be expressed as: 2 1 1F F cos= \u00d7 \u03b8 (6) 4 3 1F F cos= \u00d7 \u03b8 (7) where F3 denotes the pulling force of Spring 2 at the austenite state, and F1 represents the pulling force of Spring 1 at the martensite state. F1 and F3 can be calculated from Equation (5). The equations denote that G\u2122 represents the shear modulus of SMA spring of SSAs 1, whereas \u03b4L1 signifies the displacement of SSAs 1. Similarly, G(TA) represents the shear modulus of SMA Spring 2 of the SSAs 2, and \u03b4L2 indicates the displacement of the SSAs 2" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002452_f_version_1620712213-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002452_f_version_1620712213-Figure2-1.png", + "caption": "Figure 2. Kinematic model of the surgical assistant robot: (a) remote center motion; (b) configuration of joints and links.", + "texts": [ + " The value generated by the force/torque sensor is converted into a control command and input into position control, so the remote center can be kept solid, but care must be taken in the design of the motion generation algorithm to create a sensitive feeling. Through an experiment in which the user directly teaches by grasping the end-effector of the robot, it evaluates the ability to follow instructions well and the performance to which it maintains the remote center position. In general laparoscopic surgery, the surgical instrument requires four-degrees-offreedom motion: Pan (Roll), Tilt (Pitch), Spin (Yaw) rotational and linear movements (Forward/Backward), as shown in Figure 2a. In this study, a two-degree-of-freedom endeffector is mounted on a six-degree-of-freedom cooperative robot, and a virtual remote center is defined by a control algorithm to achieve RCM. A six-degree-of-freedom cooperative robot embodies Pan and Tilt rotational movements in the four-degree-of-freedom RCM while maintaining the remote center of three-dimensional space to form a conical trajectory. Surgery assistance is performed in such a small space that the scrub nurse has to hold an endoscopic camera between the sides of a surgeon. This robot, which maintains a non-mechanical remote center, mimics the movement of a human wrist, as shown in Figure 2a. In this case, a small device mechanism can have the effect of human grasping surgical tools in a narrow space and minimize collisions when collaborating with surgeons. However, the robustness of the controller is very important for safe surgery. As the twodegree-of-freedom motion of an end-effector can be controlled independently, this paper focuses research on the pan, tilt RCM control of the cooperative robot. The kinematic model of a robot is required as shown in Figure 2b. A robot base has a fixed frame {0} and a moving frame {e} is attached to a remote center point, and the rotation angle of each joint is qi and the link parameter is ri. The kinematic model of a robot is derived using a homogeneous transformation matrix between moving frames attached to each joint as shown in Equation (1). The forward kinematics of a robot manipulator can be obtained by a sequential product of transformation matrices as shown in Equation (2). Coordinates of the remote center point in the three-dimensional space, (xRC, yRC, zRC), can be extracted from the fourth column of the matrix T0e as shown in Equation (3), and the pan and tilt angles of the end-effector can be calculated from the rotation matrix elements of the matrix T0e as shown in Equation (4)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004027__icmes2016_03001.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004027__icmes2016_03001.pdf-Figure2-1.png", + "caption": "Figure 2. The two solutions of the FPKs for two configurations of the TLPM", + "texts": [ + " (2), by substitution of the points p and qi, the forward kinematic problem can be formulated as in the following equations: 2 2 1 0 1 2 0 2 2 3 0 3 / 3 2 / 3 / 6 / 3 / 6 / 3 x l L L l L l L L l L l L L l L (3) 2 2 3 0 2 0 2 0 2 3 / 6 3 / 3 3 / 6 3 / 3 y l L L l L L l L L l L (4) (1) 2 2 2 0 1( ) ( - )z h L l X L Y + (5) (2) 2 2 2 0 1( ) ( - )z h L l X L Y + (6) Eqs. (3-6) are the polynomial solution for the forward kinematics problem of this robot with at most two real solutions; the Cartesian positions of the moving platform are shown in Table 1 as p1=(x, y, z 1)T and p2=( x, y, z 2)T. The solutions depend only on the geometric parameters and the lengths of the prismatic actuators l1, l2 and l3; all double solutions lead to two configurations. Fig. 2 shows all distinct real configurations of this robot. 03001-p.2 In this project, as shown in Fig. 3, the workspace of the TLPM robot is defined as a region of the three dimensional space generated by the three prismatic joints in the FCS frame. The Jacobian matrix is defined as the matrix map between of the velocity of the end effector and the vector of linear actuated joint rates. Using Jacobian matrices, singularity analysis and various kinds of singularities for the TLPM robot will be investigated" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001622_f_version_1525348922-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001622_f_version_1525348922-Figure3-1.png", + "caption": "Figure 3. Body frame and NED frame representation of linear velocities [u v w], forces [X Y Z], angular velocities [p q r], attitude [\u03c6 \u03b8 \u03c8] and torque [K M N].", + "texts": [ + " A mathematical model for the autonomous navigation capability of Guanay II AUV has been elaborated in order to simulate the performance of the vehicle in open loop and to design controllers. However, modeling a marine vehicle, which is moving inside a turbulent fluid, is a complex task. In general, one can encounter two main difficulties: the selection of the coefficients and secondly their calculation. Different studies have been done to solve these problems [33\u201335]. The forces and torques that generate the vehicle\u2019s accelerations are represented in an equation, which is given as a function of the velocity vector v. Figure 3 shows the vehicle coordinates, velocities and forces. Moreover, the rigid body dynamics must take into account the Coriolis and centrifugal effects. For simplicity, they are usually calculated in the body frame. Using all of these considerations, the dynamics of the vehicle can be described as follows, as is proposed in [33]. (MRB + MA)v\u0307 + (CRB + CA)v + Dnv = \u03c4, (1) where MRB is the rigid body inertia matrix, CRB is the rigid body Coriolis and centripetal matrix, MA and CA represent the added mass matrices and Dn represent the sum of non-linear damping factors" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004637_44070_FULLTEXT01.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004637_44070_FULLTEXT01.pdf-Figure1-1.png", + "caption": "Fig. 1. (a) Components of a light-frame timber module illustrating rails, studs, beams and sheathing panels of the walls and the floor elements, (b) balloon framing and (c) platform framing.", + "texts": [ + " owadays self-bearing, prefabricated and timber-based modules have ained significant traction as favored structural components for contructing highly efficient multi-storey residential complexes, at times eaching up to six stories in height. The trend is particularly proounced in the Nordic countries where highly automated industrial roduction and effective on-site installation have made such buildings ttractive [5]. Light-frame timber modules are typical volumetric box elements ith predefined dimensions and a standardized design. The modules re composed of two long shear walls, two short transverse walls, and wo floor elements with stiff horizontal diaphragms, see Fig. 1(a). The alls are cladded by sheathings in one or two layers, the sheathings eing firmly secured to the framing members with mechanical fasteners uch as nails, screws or staples. The position and size of openings for \u2217 Corresponding author. E-mail addresses: rajan.maharjan@kau.se (R. Maharjan), le.kuai@lnu.se (L. Kuai), johan.vessby@kau.se (J. Vessby), sigurdur.ormarsson@lnu.se S. Ormarsson). doors and windows depend on the design and requirements of the final building. The floor elements (top and bottom respectively) are made up of structural timber, glulam or laminated veneer lumber (LVL). They are fully covered with sheathing panels of various materials which are mechanically jointed to the frame. These elements in turn are mechanically connected to the walls. It is also important to mention that the manner in which floor elements are assembled to wall elements can take two different approaches. The first one involves placing the floor elements in between the walls, often referred to as \u2018\u2018balloon framing\u2019\u2019, in which the continuous stacking of walls upon walls is provided, see Fig. 1(b). In contrast, the second approach involves placing the floor elements on top of or beneath the walls, see Fig. 1(c). This method called \u2018\u2018platform framing\u2019\u2019 takes its name from the notion that the ceiling in the initial storey acts as the foundation or \u2018\u2018platform\u2019\u2019 for the module above. In a building with self-bearing modules stacked side-by-side and on top of one another without any superstructure being involved, there is a need for inter-module load transfer. In Nordic countries, it is a common practice to use some type of rubber-like friction bricks between the modules to transfer the horizontal (and vertical compression) vailable online 16 February 2024 141-0296/\u00a9 2024 The Authors" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003402_9668973_09664517.pdf-Figure10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003402_9668973_09664517.pdf-Figure10-1.png", + "caption": "FIGURE 10. The elastic deformations of the EF model.", + "texts": [ + " Then the stiffness matrix K can be calculated according to (55) the equation can be derived, as shown at the top of next page. Subsequently, the deformations of m can be calculated according to (56). The detailed analytic values are shown in TABLE 7. From a simulative point of view, a finite element simulative model is established by SolidWorks according to the dimension and material parameters described in TABLE 6. When applying the identical wrenches as the analytic model to the finite element simulative model, the deformations can be obtained, as shown in FIGURE 10. The detailed simulative values are shown in TABLE 7. Since the results of the FE simulated model depend on multiple key factors (e. g. dimensions and types, boundary constraints, solver, connection constraints), it is well known that the results of the FE model are approximate numerical results. Therefore, the analytic deformation values and the simulative deformation values in TABLE 6 are basically coincident, which is acceptable for stiffness analysis, and verifies the correctness of the stiffness model established in this study" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002332_ASET_5-3508-3519.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002332_ASET_5-3508-3519.pdf-Figure5-1.png", + "caption": "Fig. 5: C-C view", + "texts": [], + "surrounding_texts": [ + "Structure design:\u00a0Shown in Fig. 1 to 6, the jet-driven vascular robot is consist of the upper and lower shell, micro-batteries, variable pump, radio control block, 12 suction nozzles, 24 2/2-way solenoid valves and operation mechanism. Its diameter is 4 mm and it could swim in blood vessels of diameter 6 mm. Suction nozzle is key for swim and posture adjustment of vascular robot. Its shape is a cylinder, with an internal Res. J. Appl. Sci. Eng. Technol., 5(13): 3508-3519, 2013 3510\u00a0 axial through-hole, whose both ends tapered outward expansion, the taper length of the outer end is shorter than that of the inner end, the middle section is the downstream segment, in Fig. 2 to 6. 6-1 until 6-12 indicate the position of suction nozzle (Jiang, 2010). Because the vascular robot swims in blood vessels, its components must be miniaturized. Micro-batteries mainly supplies energy for the wireless receiver control block and the operation mechanism, their volume should be less than 1mm in diameter. Variable pump uses the structure shown in Fig. 6, the main body is the elastic capsule structure with corrugated ring, magnetic material covering the surface outside of its end to squeeze and expansion the elastic capsule under the influence of external magnetic field, making the capsule volume changes and then suction or jet liquid. The operation mechanism is installed according to the needs, such as a manipulator is installed to clean up blood clots. Principle of swimming and posture adjustment: The jet-driven principle of jet-driven vascular robot is similar to the jet-driven of the squid, variable pump in the vascular robot quickly ejects the blood, the jet flow is faster than blood flow, blood vessels, so give the robot a reverse thrust, this reverse thrust to drive the robot forward. The propulsive efficiency of vascular robot is analyzed by following. The actual filling liquid volume of variable pump in vascular robot is the internal volume variation V in this time, the momentum variation of the liquid ejected per unit time is propel force, under unsteady conditions, the propel force is calculation by the following equation (Du, 2008): ( ) ( , ) ( , ) ( , )j jCV CS F t u x t dV u x t u x t dA t \u03c1 \u03c1\u2202 = + \u2202 \u222b \u222b (1) where, F(t) : The propel force produced by jet flow at time t \u03a1 : The density of blood uj(x, t) : Velocity of jet flow by vascular robot dv : Volume increment of elastic capsule in the variable pump dA : Area increment of internal surface of the variable pump Equation (1) is more complex to calculate the propel force F(t), but only consider the quasi-steady flow, the propel force F(t) can be simplified to Eq. (2): 2( ) n jF t A u\u03c1= (2) where, An is internal section area of suction nozzle: 2 4 n n DA \u03c0 = Dn : Nozzle diameter uj : Velocity of jet flow According to the Bernoulli equation of the unsteady flow, the pressure inside of elastic capsule of variable pump could be drawn when the vascular robot swims, such as the Eq. (3): 0 22 1 ( , ) 2 2 js j jm m m j s p up u u s tz z ds g g g g g t\u03c1 \u03c1 \u2202 + + = + + + \u2202\u222b (3) where, zm : The blood depth inside of elastic capsule zj : The depth of jet flow related the reference point pm : The pressure inside of elastic capsule pj : The pressure of jet flow um : Flow velocity inside of elastic capsule u(s, t) : Flow velocity inside of control volume s : The streamline length from the variable pump to suction nozzle, that is from s0 to sj Res. J. Appl. Sci. Eng. Technol., 5(13): 3508-3519, 2013 3511\u00a0 The loss induced by the fourth item in the right of Eq. (3) is very small, can be ignored in only consider quasi-steady flow. Assume that vascular robot swimming follows the horizontal direction and jet flow is also along the horizontal direction, pj is approximately 0, the pressure inside of elastic capsule of variable pump can be calculated by Eq. (4): 2 2 j m u p \u03c1 = (4) When the angle between the nozzle axis of the robot and the swimming direction is known, the propulsive efficiency of the robot can be calculated by Eq. (5): 2 2 2 2 2 2 coscos cos [( cos ) sin ] 2 j j j j j UuTU V U uTU u U u t \u03b8\u03b8\u03b7 \u03c1\u03b8 \u03b8 \u03b8 = = ++ \u2212 + (5) where, U: Swim velocity of vascular robot V: The volume of elastic capsule of variable pump As the blood density is 1.056 g/cm3, vein blood flow is 12 cm/s, the volume of elastic capsule of variable pump is 56.55 mm3, nozzle diameter is 0.5 mm, uj is 14.4 cm/s, the angle \u03b8 between the nozzle axis of the robot and the swimming direction is 0, the robot moving velocity U is 3 mm/s, then the propulsive force is 0.0062 N calculated by (2), (4), (5), the pressure Res. J. Appl. Sci. Eng. Technol., 5(13): 3508-3519, 2013 3512\u00a0 inside of elastic capsule is 10.95 Pa, the propulsive efficiency \u03b7j is 41.6%. The fluid flow path analysis under vascular robot swimming and posture adjustment: Figure 7 is a posture diagram of jet-driven vascular robot, vascular robot suspended in the blood has six degrees of freedom, could achieve 12 swimming actions. The connection relationship among of suction nozzle, variable pump and solenoid valve in vascular robot is shown in Fig. 8. Vascular robot achieves the movement shown in Fig. 7, by through connection and disconnection between of different suction nozzle and the entrances and exits of the variable pump. Under the different posture of vascular robot, the connection and disconnection between of suction nozzle and variable pump, open and closed of solenoid valve are described in detail below (Jiang, 2010). Forward: The solenoid valve 7-1I, 7-2O open, blood enter the variable pump 4 from the pump suction nozzle 6-1 and jet by the suction nozzle 6-2, drive the robot swim forward (Fig. 2 in the direction of the arrow D). Backward: The solenoid valve 7-2I, 7-1O open, blood enter the variable pump 4 from suction nozzle 6-2 and jet by the suction nozzle 6-1, drive the robot swim backwards. Upward translation: The solenoid valve 7-7I, 7-8I, 7- 9O and 7-10O open, blood enter the variable pump 4 from the suction nozzle 6-7, 6-8 and jet by the suction nozzle 6-9, 6-10 and drive the robot to upward translation. Downward translation: The solenoid valve 7-9I, 7- 10I, 7-7O and 7-8O open, blood enter the variable pump 4 from suction nozzle 6-9, 6-10 and jet by the suction nozzle 6-7, 6-8, drive the robot to downward translation. Left translation: The solenoid valve 7-3I, 7-4I, 7-5O and 7-6O open, blood enter the variable pump 4 from the suction nozzle 6-3, 6-4 and jet by the suction nozzle 6-5, 6-6, drive robot to left translation. Right translation: The solenoid valve 7-5I, m7-6I, 7- 3O and 7-4O open, blood enter the variable pump 4 from the suction nozzle 6-5, 6-6 and jet by the suction nozzle 6-3, 6-4, drive the robot to right translation. Front left tilt: The solenoid valve 7-6I, 7-5O open, blood enter the variable pump 4 from the suction nozzle 6-6 and jet by the suction nozzle 6-5, drive the robot to front left tilt. Front right tilt: The solenoid valve 7-3I, 7-4O open, blood enter the variable pump 4 from the suction nozzle 6-4 and jet by the suction nozzle 6-3, drive the robot to front right tilt. Front upward tilt: The solenoid valve 7-10I, 7-9O open, blood enter the variable pump 4 from the suction nozzle 6-10 and jet by the suction nozzle 6-9, drive the robot to front upward tilt. Front downward tilt: The solenoid valve 7-8I, 7-7O open, blood enter the variable pump 4 from the suction nozzle 6-8 and jet by the suction nozzle 6-7, drive the robot to front downward tilt. Clockwise rotation around the vertical axis: The solenoid valve 7-12I, 7-11O open, blood enter the variable pump 4 from the suction nozzle 6-12 and jet by the suction nozzle 6-11, drive the robot to clockwise rotation around the vertical axis. Counterclockwise rotation around the vertical axis: The solenoid valve 7-11I, 7-12O open, blood enter the variable pump 4 from the suction nozzle 6-11 and jet by the suction nozzle 6-12, drive the robot to counterclockwise rotation around the vertical axis." + ] + }, + { + "image_filename": "designv7_3_0002781_1145_3629606.3629628-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002781_1145_3629606.3629628-Figure11-1.png", + "caption": "Figure 11: The gadget structure.", + "texts": [ + " A chemical reaction occurs between them to produce a humidity color, thus achieving a surface and texture similar to bronze. Meanwhile, we can control the amount of patina by controlling the humidity of the air. The robot body consists of two facial expression gadgets, a central pillar, a waist layer, and a top decorative layer (Figure 9). The two gadgets are symmetrical at the top and bottom. Each gadget has three concentric rings. All the six rings are connected to the central pillar with a planetary gear mechanism (Figure 11). Each ring can be independently rotated around the central pillar. In each gadget, the horn-ring, the face-ring, and the mouth-ring are arranged in order, from the outside to the inside. \u2022 Horn-ring: the outer ring, carrying three horns of different shapes. The base of the horn-ring is a metal disc, which is linked to the central column by means of bearings. A servo motor is fixed to the center pillar through the top metal disc, rotating the horn-ring through a gear set. The three horns are fixed to the metal disc by reinforcement bars at 120-degree intervals" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003523_f_version_1709282395-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003523_f_version_1709282395-Figure1-1.png", + "caption": "Figure 1. The body-fixed frame and the corresponding Euler angles.", + "texts": [ + " Experimental results demonstrate that this improved algorithm reduces oscillations compared to approaches that do not incorporate second-order information, such as velocities. The simulation environment is built based on gym-pybullet-drones [43]. In this work, a QUAV with an \u201cX\u201d configuration is considered. Similar to many fixed-wing UAVs [44], it has six degrees of freedom. Its position and Euler angles are defined as p = [x, y, z]T and \u0398 = [\u03d5, \u03b8, \u03c8]T , respectively. The Euler angles as shown in Figure 1 are obtained following the intrinsic z-y-x sequence (or, equivalently, extrinsic x-y-z sequence). Therefore, the rotation matrix from the body-fixed frame {xb, yb, zb} to the earth frame {xe, ye, ze} is calculated by R = [xb, yb, zb] = c\u03b8c\u03c8 c\u03c8s\u03b8s\u03d5 \u2212 s\u03c8c\u03d5 c\u03c8s\u03b8c\u03d5 + s\u03c8s\u03d5 c\u03b8s\u03c8 s\u03c8s\u03b8s\u03d5 + c\u03c8c\u03d5 s\u03c8s\u03b8c\u03d5 \u2212 c\u03c8s\u03d5 \u2212s\u03b8 s\u03d5c\u03b8 c\u03d5c\u03b8 , (1) where the coordinates of xb, yb, and zb are in the earth frame, zb = [zx b, zy b, zz b] T , c\u03be and s\u03be (\u03be = \u03d5, \u03b8, \u03c8) are short for cos \u03be and sin \u03be, respectively, and R \u2208 SO(3). In this work, we use the frame of SE(3) control [45] to avoid using a transformation matrix W between the Euler angles \u0398 and the angular velocity \u03c9 = [\u03c9x, \u03c9y, \u03c9z]T , which suffers from singularity as \u03b8 approaches \u03c0 2 " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004429_9647862_09706262.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004429_9647862_09706262.pdf-Figure5-1.png", + "caption": "Fig. 5. Position measurements visualised and evaluated in GOM Inspect (top) and associated diagrams with experimental and simulation data (bottom).", + "texts": [ + "69 Nm/rad and for the third 0.61 Nm/rad. The following analyses were performed in a transient study with 10 seconds of running time using a Backward Euler solver with a consistency tolerance of 10\u22129 as default value. The input parameter of the simulation is the corresponding pulled tendon length to achieve a bending angle of 36\u00b0. As output parameter Simscape calculates the position of calculation points. We defined our eight calculation points at the top and bottom of each disc shown as black dots in the middle plot in Fig. 5. At these specific points we compared the results in position for planar motion and pulled tendon length of the analytical CC-kinematic and the rigid MBS model in absence of gravity. Even though the model is dynamic, here we only study the static deviation at the end of the deformation process. In order to be able to model the behavior of the switchability of the stiffness in the simulation process, all three segments were first assumed to be ideally stiff. Starting from the bottom up, only the corresponding segment was discretized as described above while the other two were still defined as stiff and the position adjustment was calculated up to an angle of 36\u00b0", + " The pulling lengths of the tendons required for the angular adjustment were determined in preliminary tests and marked accordingly in order to be able to set them correctly by hand in the measurements. The manipulator was scanned from 20 different perspectives for each target shape. Reference points on the surface of the latex membrane enabled the software to recognize the different perspectives and combine them into a 3D mesh. With the GOM Inspect software, it is possible to determine the bending angle, the required tendon length and the position of the segments from the mesh (see Fig. 5 above plots). The red points marked in the left plot in Fig. 5 were defined as fixed reference points for the position measurement. To compare the measurements with the simulation results, the positions of the points at the top and bottom of the discs corresponding to those of the simulation were determined by transformation. In view to compare the experimental values of the three shapes determined with the optical measurement system with the analytical solution (CC-kinematics) and with the kinematic simulation (rigid MBS), all results are shown in a diagram per target shape in Fig. 5. It can be seen that both calculation methods give similar results to the measurement in absence of gravity. The error here is less than 2%. The small error, despite the absence of gravity in the calculations, could be explained by the fact that it was assumed that the powder and the membrane have no influence on the stiffness and the bending curve in the soft state. Even if the results of the first calculation step without gravity seem to represent the system sufficiently, i.e., the much simpler CC calculation could also be used, this only applies to the very specific configuration of the system investigated without applied forces and is not transferable", + " For this reason, the own weight deformation is larger in the simulation than in the measurements. The highest position error under gravity occurs for the C-Form in the second segment due to the larger arms of lever from the center of masses. To reduce the position error, the stiffness of the second segment was calculated from force-displacement measurements and implemented into the simulation model, as described in Section IV. A. Stiffness Characterization. Implementing this corrected stiffness into the rigid MBS model leads to the purple squares in the C-form in Fig. 5. Using the characterized stiffness of the middle segment in soft state, it was possible to reduce the position error to 3%. Nevertheless, the error is greater than for the calculations without gravity, since only the stiffness of the second segment was measured and implemented. To obtain an accurate calculation of the position under gravity, a stiffness characterization of all three segments is required. The upright C-form and S-form have lower errors under gravity because they are more upright, so the masses of the following segments have smaller arms of lever. Hence the simulation with corrected stiffness is only shown for the C-form in Fig. 5. The design of a robot structure with variable stiffness through the use of particle jamming was demonstrated. Using the example of a 3-segment robot arm, it was shown that by using this structure, combined with only two tendon actuators, various shapes can be realized by planar deformation. The number of actuators required could be significantly reduced compared to existing systems. This demonstrates that by using structural elements with variable stiffness in combination with tendon actuators, it\u2019s possible to develop underactuated systems that can realize complex shapes" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003287_6514899_10288498.pdf-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003287_6514899_10288498.pdf-Figure9-1.png", + "caption": "FIGURE 9. (a) Motor front seat; (b) Motor back seat; (c) Shaft sleeve.", + "texts": [ + " Flat sections were also cut into the shaft to enhance the stability of locking screws. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/ VOLUME XX, 2017 9 As shown in Fig. 8, the motor assembly includes front and back motor seats to minimize vibration and a shaft sleeve to connect the gear assembly. The front seat provides a groove into which the motor is inserted with four screw holes corresponding to holes on the motor (Fig. 9(a)) and the upper section of the back seat can be adjusted vertically by screws to lock the motor securely in place (Fig. 9(b)). A sleave is fit over the motor shaft to increase the diameter to 10 mm, which corresponds to the diameter of the hole in the gear assembly (Fig. 9(c)). Note that the sleeve is tightly locked to the front end of the motor via three screw holes evenly spaced around the circumference (i.e., at angles of 120 degrees). Fig. 10 illustrates the configuration of the gears driving Linkage-I, where Gear-I and Gear-II have the same number of teeth and Linkage-I and Gear-II are attached to the same shaft (Shaft-II). Thus, any counterclockwise rotation of Motor-1 and Gear-I causes an equal clockwise rotation of Gear-II as well as Linkage-I. Fig. 11 shows the belt-drive system used for Linkage-II" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002925_f_version_1445520180-Figure15-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002925_f_version_1445520180-Figure15-1.png", + "caption": "Figure 15. Measurement apparatus for drag force.", + "texts": [ + " The electric current and the voltage of the battery in the robot were simultaneously measured. The circulating water tank was an impeller type and was driven by a three-phase 200 W AC motor. The water speed in the circulating water tank can be controlled in 0 mm/s to 570 mm/s by a small inverter (VfnC1-2002P). The drag of each propulsive speed was measured as we changed the water speed in the circulating water tank according to the propulsive speed of the robotic fish. An overview of the apparatus for measuring the drag force is shown in Figure 15. The robot was fixed to the measuring apparatus so that it could not move, allowing the drag force in the circulating water to be measured by the load cell. Since the robot was fixed, the drag force varied with the water flow speed. The drag force was measured for water flow speeds of 20 to 200 mm/s in steps of 20 mm/s. In addition, the drag force was also measured for water flow speeds corresponding to the actual measured speeds of the robot during the swimming experiments. These were 21, 77, 80, 102, 107, 108, 110, and 111 mm/s, and were obtained by changing the phase difference between the tail-fin motors" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003643_09_epjconf162261.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003643_09_epjconf162261.pdf-Figure2-1.png", + "caption": "Figure 2. Schematic of the setup: The vibration generator consisted of an electromagnetic shaker that drove a 45 cm-by-45 cm square plate, that was screwed to a pair of square, aluminum tubes that strengthen the base. The driving sinusoidal signal was generated by a function generator, which was then amplified by a power amplifier. The shaker was cooled by air. We measured the vibration amplitude by imaging the vibrating plate via a highspeed camera (Photron FASTCAM SA5). The first peak of the vibration was large relative to later vibration, but contributed insignificantly to the packing compared to the total amount of energy from the vibration.", + "texts": [ + "1 between particles and the surface, or a sand paper surface, which had a higher friction coefficient such that particles only rolled when we tilted the surface. We refer to the Teflon and sand paper as low friction (LF) and high friction (HF) bases. We prepared columns with different diameters D and initial heights, which were chosen to be around the critical height hc in our previous results [10]. Columns were placed on a vibration plate and we applied sinusoidal vibrations to induce collapse (See Fig.2). The sinusoidal vibration had frequency f = 58.6\u00b10.3 Hz and dimensionless vibration strength \u0393 = A\u03c92/g = 2.0\u00b10.2, which were kept unchanged in all runs. On top of the plate, we glued either a Teflon sheet or sand paper as described earlier. All the collapse dynamics were captured by high speed video imaging at 250 frame/s on the LF base and 60 frame/s on the HF base. Homemade Python codes were used to post-process the images and the centroid height h(t) of the packing in the images was found (Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000247_6514899_10494537.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000247_6514899_10494537.pdf-Figure1-1.png", + "caption": "FIGURE 1: A linear translation by utilizing a zigzag walking movement.", + "texts": [ + " Consequently, one of the legs lifts off the ground while the robot balances on the other leg, forming a pivot point. This results in a rotational movement where the wheel continues to turn until the other leg makes contact with the ground again. Similarly, applying current in the reverse direction causes the opposite leg to become the pivotal axis of rotation. By rapidly turning the wheel from side to side for brief durations (\u2264 100ms), a zigzag movement is achieved that closely approximates a forward motion (Figure 1). By adjusting the rotation periods of the wheel on each angular direction, one can create circular or curved movements at will, up to a pure rotation. This is demonstrated in the videos showcasing the robot in action [20] or in video. III. DYNAMIC ANALYSIS A dynamic model has been developed by formulating EulerLagrange equations, based on the assumption that at any given moment, one of the robot\u2019s legs is in contact with the ground. This model effectively captures the system\u2019s dynamics, offering valuable insights into the robot\u2019s behavior and aiding in the analysis and development of control strategies" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002585_f_version_1709037070-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002585_f_version_1709037070-Figure1-1.png", + "caption": "Figure 1. Biomimetic structure and surface for grasping. The wedge-shaped surface, suction cup surface and claw thorn surface find extensive applications in grasping tasks performed underwater, in vacuum environments, and in the air. With the combination of the bioinspired surface, composite biomimetic adhesive surface is possible to be attached to various roughness and curvature target surfaces with all-direction bearing. Adapted with permission from [8]. Copyright 2005, SpringerVerlag Berlin Heidelberg. Adapted with permission from [9]. Copyright 2015, WILEY-VCH Verlag GmbH & Co. Adapted with permission from [10]. Copyright 2021, IEEE. Adapted with permission from [11]. Copyright 2019, American Chemical Society.", + "texts": [ + " Therefore, achieving more biological surface functionalities, such as omnidirectional bearing and higher adaptability to roughness, becomes crucial, given the current manufacturing capabilities. Bioinspired structures and surfaces have certain limitations in terms of the usage environments, surface roughness, and curvature. They are typically designed for specific adhesion environments, with pressure adhesion often used in atmospheric or underwater high-pressure conditions [1,2], claw-like attachment structures suitable for air environments, and gecko-inspired adhesive surfaces often used in clean environments such as air or vacuum [3] (Figure 1). Additionally, the adaptability of bioinspired structures and surfaces to surface roughness varies. Pressure adhesion surfaces require relatively small surface roughness compared to the size of the suction cup; otherwise, it is challenging to generate Biomimetics 2024, 9, 144. https://doi.org/10.3390/biomimetics9030144 https://www.mdpi.com/journal/biomimetics Biomimetics 2024, 9, 144 2 of 26 a seal and create internal negative pressure [4,5]. Claw-like attachment structures are suitable for relatively rough surfaces, making mechanical interlocking between the claws and the target surface more achievable [6]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000765_f_version_1624330364-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000765_f_version_1624330364-Figure2-1.png", + "caption": "Figure 2. Definitions for frames and vectors.", + "texts": [ + " This means that the robots can transport the object while keeping the object\u2019s attitude stable. On the other hand, when the computed slope is greater than the threshold, that grid is set to be a non-traversable area. Through this process, the elevation map is transformed into the traversability map, which is composed of traversable and non-traversable areas. Note that non-traversable areas in the traversability map are assumed as obstacles. To describe motions of robots and an object, frames and vectors are defined as shown in Figure 2. The inertial frame is defined using unit vectors n\u0302k for k = 1, 2, and 3, and the body frame that is fixed on the object\u2019s center-of-mass is defined by b\u0302k. The position and velocity vectors of i-th robot with respect to the inertial frame are defined as ri = [ri,x, ri,y, ri,z] T \u2208 R3 and r\u0307i = [r\u0307i,x, r\u0307i,y, r\u0307i,z] T \u2208 R3, and the position vectors of each robot with respect to the body frame are defined as pi = [pi,x, pi,y, pi,z] T \u2208 R3. In addition, the object\u2019s position and velocity vectors with respect to the inertial frame are defined as rc = [rc,x, rc,y, rc,z]T \u2208 R3 and r\u0307c = [r\u0307c,x, r\u0307c,y, r\u0307c,z]T \u2208 R3" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002121_Mechatr_2010Proc.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002121_Mechatr_2010Proc.pdf-Figure5-1.png", + "caption": "Fig. 5. Three-dimensional mode shapes of the first four modes of the vertical dynamics of the piezoelectric actuator including a thin disk flexible load.", + "texts": [ + " If a thin disk is applied, the low order bending modes of the disk will appear in the same frequency range as the low order extension modes of the tube. As a result, the relative ordering of the low order resonant and anti-resonant modes of the thin disk may deviate from the nominal load case (h = 1, 52 mm) causing a large mismatch in phase between control system and actuator if the control system is tuned for the nominal load case. Ultimately, this may affect the stability of the feedback loop. To illustrate this effect, the three dimensional mode shapes of the first four modes of the actuator in combination with a thin disk is shown in Fig. 5. From this Figure it is clear that the mode shape of the second mode is dominated by the bending of the disk. This case corresponds to the case shown in blue in Fig. 4. For thicker disks, the low order bending modes appear close to the third and higher order modes in the same frequency range as the radial modes. Modes dominated by radial displacement (see for example Fig. 5, right) are in general hard to control since they tend to appear close together. Therefore, in a practical control design case, the bending modes of the thicker disks (1.52 and 2.28 mm) appear in a frequency range where excitation of modes by the control system is avoided by providing roll off. The dynamics of the piezoelectric actuator are also influenced by the dynamics of a flexible actuator mount. The effect of solid steel base on the dynamics of the tube is shown in Fig. 6. The presence of the base introduces a series of resonant and anti-resonant modes which appear in pairs" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001462_9831196_09830834.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001462_9831196_09830834.pdf-Figure3-1.png", + "caption": "Fig. 3. Actual and erroneous hole locations. The center of the actual hole in the board is indicated by a blue dot. The baseline planner is given an erroneous estimate of the hole locationXdes, uniformly distributed in a ring (red shadowed region) around the actual center of the hole with inner and outer radii of 0.21[mm] and 0.8[mm], respectively. The peg (yellow circle) is illustrated at a possible Xdes. The diameters of the peg and hole are 4.2[mm] and 4.6[mm], respectively.", + "texts": [ + " Simulations of peg insertion were conducted under the following conditions: Size: The diameters of the peg and hole were Dp = 4.2[mm] and Dh = 4.6[mm], respectively. Board location: The board was randomly located in the x, y plan, at the beginning of each episode, with uniform distribution in the working space. Location uncertainty: A random translation error was added to the actual center of the hole to generate the desired location Xdes that was sent to the baseline planner. Errors were uniformly distributed in a ring with inner and outer radii of 0.21[mm] and 0.8[mm], respectively, as shown in Fig. 3, to assure overlap between the peg and the board. Orientation uncertainties: Orientation uncertainties were included only during testing. The orientation of the peg was uniformly distributed in a cone with apex angle of 24\u25e6 around the z axis. Three types of impedance policies were compared, with three types of stiffness and damping matrices: (1) diagonal, (2) non-diagonal, and (3) asymmetric matrices, as detailed in Section III-B. Six training sessions were performed with each type of impedance policy to support statistical evaluation" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004301_6514899_10366270.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004301_6514899_10366270.pdf-Figure4-1.png", + "caption": "FIGURE 4. Schematic of the virtual force of the improved APF.", + "texts": [ + " Next,Rmax is used to constrain the envelope of the quadrotor-payload system and thus achieve less conservative obstacle avoidance. Considering the real-time swing position of the payload, the improved repulsive force function is designed as follows: Frepi = kri[ 1 \u03c1oi(\u03be\u2217,\u03beoi) \u2212 1 \u03c1\u2217 ] 1 \u03c1oi2(\u03be\u2217,\u03beoi) \u2207\u03c1oi(\u03be\u2217, \u03beoi) , \u03c1oi \u2212 \u03c1\u2217 \u2264 0 ; 0 , \u03c1oi \u2212 \u03c1\u2217 > 0 ; \u03c1\u2217 = Rmax + roi +\u2206dmin (27) Fall = Fattuav + n\u2211 i=1 Frepi (28) where roi is the radius of the i-th obstacle and Rmax is the maximum envelope circular radius of the quadrotor-payload system. Remark 1: The virtual force diagram of the improved APF is shown in Fig.4. The envelope circular is used for obstacle avoidance constraints of the quadrotor-payload system. Obviously, changing the original obstacle avoidance distance \u03c10 (\u03c10 = l+ roi+\u2206dmin) to \u03c1\u22170 (\u03c1 \u2217 0 = Rmax+ roi+\u2206dmin) with the change of the swing angle can achieve less conservative obstacle avoidance detection. The application of the improved APF function for obstacle avoidance is closer to the practical case of quadrotor-payload flight, which has the advantage of improving the timeliness and safety of flying" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002519_cle_download_252_185-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002519_cle_download_252_185-Figure6-1.png", + "caption": "Figure 6. Six-legged Robots: RHex", + "texts": [ + " In this case, robot alternately rests on three of six legs: two non-adjacent angled legs on one side of body and one central on other. That is, center legs on both sides have a greater load than corner legs. To reduce this load, the central legs are located at greater distance from longitudinal axis of symmetry than angular legs. 7. Great example would be RHex, bio-inspired hex robot built for traversing terrain. He can ride on stones, mud, sand, snow and railway tracks, and even climb stairs and descents up to 45 degrees (Figure 6) [24] [25]. 8. Octopod (eight-legged robot) is like prototypes of spiders, scorpions, crab, etc. They are used for: scientific missions, moving in pipes, for mine clearance, that is, to obtain information about an object, for example, monitoring and moving often in hard-to-reach, extreme and unsafe places [26] [27] [28] [29]. Figure 7 shows typical example of an octopod [27]. (b) T8X Robot 9. T8X is only robot in market that combines so much resemblance to real spider with fine movements, programmability, and customizability" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000077_f_version_1703033959-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000077_f_version_1703033959-Figure2-1.png", + "caption": "Figure 2. Structure of miniature\u2212sized hollow-cup motor.", + "texts": [ + " For the application of a fiber positioner, the use of highly compact microdrives is imperative. After extensive evaluation, a \u03c64 mm hollow-cup motor, provided by NAMIKI Precision Jewel Co., Ltd., Tokyo, Japan, has been identified as the optimal choice. Table 1 delineates the motor\u2019s detailed specifications. The compact microdrive system is instrumental in ensuring stability and precision within the realm of micro-precision instrumentation. The primary subject of our investigation is the 4 mm motor, whose structural components are depicted in Figure 2. The key features of the motor\u2019s construction are as follows: (1) The stator winding consists entirely of self-supporting copper coils arranged in a skewed pattern, as opposed to coils wound on a laminated iron core. This innovative coreless stator design is lightweight and devoid of cogging torque, which enhances its performance. (2) The motor\u2019s compact architectural design incorporates an internal rotor that is a singular cylindrical permanent magnet, magnetized in the diametrical plane. This feature results in low rotational inertia and high responsiveness to changes in rotational speed" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002840_f_version_1665489054-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002840_f_version_1665489054-Figure5-1.png", + "caption": "Figure 5. Winch with ball spline. (a) Picture of the winch developed at Irma l@B (University of Bologna). (b) The motor (M) is fixed to the frame and coupled to the drum (D) using a ball spline (P) to transmit the torque. The drum is mounted onto two plates (which form the carriage C), and can translate thanks to a screw/nut pair (H).", + "texts": [ + " the carriage, whereas the drum can rotate supported by two bearings (R). The rotational motion of the drum is transformed into the translation of the carriage along two prismatic pairs (P) thanks to a helical pair (H). The latter is usually realized using a screw/nut system, where the nut is fixed to the drum. This solution has the same kinematic behavior as the rototranslating design, and its transmission ratio is hereby reported for completeness: K = \u221a K2 S + r2 D [m/rad] (3) The winch design proposed in this paper, called Spline Winch, is shown in Figure 5. The proposed design concept aims to merge the benefits of the rotrotranslational-drum design with the ones of the translating-motor system, as detailed in Section 4. The motor (M) is fixed to the winch frame, while the drum (D) can (see Figure 5): \u2022 Rotate since a spline shaft is rigidly attached to the motor axis, and a spline nut is attached to the drum; the spline shaft/nut pair is effectively a prismatic joint (P), designed so as to transmit torque while allowing axial translation; \u2022 Translate since a screw shaft is rigidly attached to the winch frame, and a screw nut is attached to the drum; this is the classical helical pair (H) used in all winch designs. The drum is supported via two plates (or carriages, C): a revolute joint (R) and two prismatic joints (P) are embedded into each plate, so that the drum can freely rotate w" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000477__cccar2022_02021.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000477__cccar2022_02021.pdf-Figure1-1.png", + "caption": "Fig. 1. Target ball positioning tool.", + "texts": [ + " The target ball positioning tool adopts four reflective target balls to form features. Considering the end effector tool during the movement of the mobile manipulator, the target ball positioning tool is designed with general parts. No matter how the end effector tool is selected, the flange at the end of the manipulator does not change, so the connector is designed to be fixed on the flange of the outer ring, and the height position of the target ball tool is adjusted according to the end of the manipulator to prevent collision. As shown in figure 1 below: In order to accurately describe the pose of the target ball positioning tool, it is necessary to establish the target ball positioning tool coordinate system {\ud835\udc42\ud835\udc42\ud835\udc61\ud835\udc61} according to the four target balls. To establish a coordinate system, you first need to number the target balls. As shown in figure 2, mark the numbers of the four target balls, \ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc350,\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc351,\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc352,\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc353. The center direction of \ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc351\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc350 is the positive direction of the \ud835\udc4b\ud835\udc4b\ud835\udc61\ud835\udc61 axis, and the center direction of \ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc350\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc35\ud835\udc352 is the positive direction of the \ud835\udc4c\ud835\udc4c\ud835\udc61\ud835\udc61 axis" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.38-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.38-1.png", + "caption": "FIGURE 21.38. Plans of six wind tunnels for full-scale testing of road vehicles. (a)Volkwagen, Wolfsburg, Germany; (b) Ford, Detroit, USA; (c) F.K.F.S., Stuttgard, Germany; (d) Pininfarina, Torino, Italy; (e) M.I.R.A., Lindley Nuneaton, G.B., (f) Nissan, Oppama Yokosuka, Japan.", + "texts": [ + " An alternative is the use of closed test chambers with porous walls, that is walls allowing a certain quantity of air to be extracted from the flow, with 21.6 Experimental study of aerodynamic forces 157 consequent reduction in the thickness of the boundary layer. Another possibility is the use of adaptive test chambers, in which a number of actuators allow the shape of the test chamber to be changed so that the streamlines at a certain distance from the vehicle are similar to those occurring in a free flow. Sketches of six of the most important vehicular wind tunnels are plotted in Fig. 21.38. Three of them have a closed circuit and three are open, two with air recirculation. The cross section of the Pininfarina wind tunnel is shown in Fig. 21.39, as an example of a modern climatic aerodynamic tunnel with open circuit and air recirculation and open test chamber. Peculiar difficulties encountered in wind tunnel testing of vehicles are linked with the presence of the ground. To simulate the motion of the ground with respect to the vehicle, a sort of carpet moving at the speed of the air should be used, with the wheels rolling on it" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000709_14_1_article-p45.pdf-Figure17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000709_14_1_article-p45.pdf-Figure17-1.png", + "caption": "Fig. 17. The moment values and the regions they applied in the simulations realized for a 12-rotor drone system", + "texts": [ + "091 Hz 10-rotor drone structure (Mode 4) have been represented. As seen from the results deformation effects are occurring in 9 of the 10 blades and their motor holder parts. Finally, in the Mode 6 structure which was analyzed under the 7.0927 Hz frequency similar results to the Unauthenticated | Downloaded 12/20/24 06:11 AM UTC previous modes have been obtained in terms of the deformation due to the moment effect. The last drone modal analyzed in this work is the drone structure consisting of 12 rotors as shown below (Fig. 17). Figure 18 shows the main body and interior view deformation results obtained after applying different moments to the 12-rotor drone structure. Similar to the drone structures previously analyzed, in the 12-rotor structural deformations have been especially affecting the motor holder parts and their relevant extreme regions. When the results obtained for the frequencies of 6.8307 Hz in Fig. 19(a) and 6.8341 Hz in Fig. 19(b) are Unauthenticated | Downloaded 12/20/24 06:11 AM UTC examined, in both Mode 1 and Mode 2 structures, it is seen that deformations appear in 10 of the 12 blades and their relevant motor holders" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure23.2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure23.2-1.png", + "caption": "FIGURE 23.2. Forces acting on an articulated vehicle moving on an inclined road. (a) Tractor or vehicle with more than two axles; (b) trailer.", + "texts": [ + " Operating in the same way, at 70 km/h = 19.44 m/s the value of \u0394x is 4.0 mm for all tires. The other results are K1 = 8.490 \u00d7 10\u22126 s2/m, K2 = \u22125.867 \u00d7 10\u22125 s2/m, Fz1 = 4643 N, Fz2 = 3542 N. d) The acceleration is V\u0307 = \u22123.924 m/s2. As the speed is the same as in case b), the same values for \u0394x, K1 and K2 hold. The forces are Fz1 = 5498 N, Fz2 = 2813 N. If more than two axles are present, even in symmetrical conditions the system remains statically indeterminate and it is necessary to take into account the compliance of the suspensions (Fig. 23.2a). The equilibrium equations (23.3) still hold, provided that the terms Fx1 + Fx2 , Fz1 + Fz2 , Fz1(a + \u0394x1) \u2212 Fz2(b \u2212 \u0394x2) 23.1 Load distribution on the ground 189 are substituted by \u2211 \u2200i Fxi , \u2211 \u2200i Fzi , \u2211 \u2200i Fz1(xi + \u0394xi) , where distances xi are positive for axles located forward of the centre of mass and negative otherwise. For computation of normal loads on the ground a number (n \u2212 2) of equations, where n is the total number of axles, must be added. Each one of them simply expresses the condition that the vertical displacement of the point where each intermediate suspension is attached to the body is compatible with the displacement of the first and the last", + "3), form a set of n equations that can be solved to yield the n normal forces acting on the axles. Remark 23.1 Forces Fzi can never become negative: If a negative value is obtained, it means that the relevant axle loses contact with the ground and the computation must be repeated after setting the force to zero due to the relevant axle. The procedure is repeated until no negative force is present. 23.1 Load distribution on the ground 191 In the case of articulated vehicles with a tractor with two axles and one or more trailers with no more than a single axle each (Fig. 23.2), the computation is straightforward. In this case, the equilibrium equations of the tractor are\u23a7\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23a8 \u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23a9 n\u2211 i=1 Fxi \u2212 Fxt + Fxaer \u2212 mg sin(\u03b1) = mV\u0307 n\u2211 i=1 Fzi \u2212 Fzt + Fzaer \u2212 mg cos(\u03b1) = 0 n\u2211 i=1 Fzi (xi + \u0394xi) + Fzt c + Fxt ht + mghG sin(\u03b1) \u2212 Maer+ +|Fxaer |hG = \u2212mhGV\u0307 , (23.9) where forces Fxt and Fzt are those the tractor exerts on the trailer, as in the figure, the number of axles of the tractor is assumed to be n (in the present case n = 2), the moments are computed with reference to point O, and the aerodynamic forces and moments are those exerted on the tractor only" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001309_f_version_1698070838-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001309_f_version_1698070838-Figure3-1.png", + "caption": "Figure 3. Simplified coordinate transformation model for a mobile robot.", + "texts": [ + " The second factor is the speed control of the adjustment. To reduce the system lag caused by untimely adjustments and vehicle body vibration caused by overshoot, the telescoping speed of each leg needs to adapt to the terrain changes. 2.2.1. Attitude Angle Control Model Establishment This section introduces the attitude angle control method based on ideal ground conditions (i.e., an ideal plane with a hill). Before introducing the control method, several related concepts are defined, as shown in Figure 3: Agriculture 2023, 12, x FOR PEER REVIEW 6 of 29 This article mainly considers the need for the vehicle to maintain a horizontal posture when walking in a greenhouse; therefore, the control targets for pitch and roll angles are set to 0. To achieve the fastest response speed, the attitude angle is adjusted based on the principle of keeping the center point stationary. That is, in each adjustment cycle, the four legs are synchronized to extend or retract based on the geometric center point of the vehicle plane" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004594_13_submission_95.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004594_13_submission_95.pdf-Figure7-1.png", + "caption": "Figure 7: The Articulation of the Thumb", + "texts": [ + " c) Motor M3 can be moved to impart only abduction and adduction if and only if effects on M2 and M1 are mitigated. Since the thumb has got two DoFs (one palmer and one radial), to incorporate the same two motors have been utilized. Motor M4 creates the radial motion to the base of the thumb Motor, M5 the combined motion for the phalanx of the thumb with the aid of one worm wheel pairs as shown in Figure 6. IV. KINEMATIC ANALYSIS AND CONTROL STRATEGY Quasi-static motion as well as force analysis has been accomplished analytically. Figure 7 shows that the fingertip velocity initially increases and then decreases as the fingertip approaches the object (fine manipulation) whereas the grasping force imparted by the finger gradually increases to ensure a stable grasp, as evident through Figure 8. Proceedings of the 1st International and 16th National Conference on Machines and Mechanisms (iNaCoMM2013), IIT Roorkee, India, Dec 18-20 2013 The finger tip trajectory and the workspace of the designed finger were simulated without abduction and adduction and are shown in Figure 10 and Figure 11 respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004115_tr_pdf_ADA593274.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004115_tr_pdf_ADA593274.pdf-Figure5-1.png", + "caption": "Figure 5 : See-thru packaging design for DR vehicle", + "texts": [ + " In addition, the side-pod sections of the shell house the computing and DC/DC power stage electronics, as well as the wireless command-and-control (C&C) and video/audio transmitters and transceivers. The rear section of the main body-section supports the rear wheels, which are driven off a brushless DC motor running through a single 3:1 gear-up train driving a fixed shaft; a co-axial slip-clutch protects both motor and drivetrain against overloads. The remainder of the space is primarily taken up by the wiring harness to distribute power, signal and video to and from the actuation, sensing, computing and communication systems. The internal see-through view of the DR-vehicle shown in Figure 5, depicts the main elements internal to the vehicle: The electronics system for the DR vehicle are based on a straightforward centralized architecture. An on-board CPU is interfaced to the OCU through a wireless modem transceiver unit, allowing it to exchange C&C information with the operator. All relevant actuation (drive, steering, camera-pitch) is performed through PWM control over digital I/O ports; motion-sensors are monitored on thresholded TTL input-lines. Video and audio are directly fed into a separate analog wireless transmitter" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004998_8600701_08625490.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004998_8600701_08625490.pdf-Figure1-1.png", + "caption": "FIGURE 1. Mobile robot coordinate system.", + "texts": [ + " According to the conversion between the coordinate systems, the information of the robot and surrounding obstacles in the global coordinate system can be obtained. The environmental model uses the grid method. Choosing the reasonable grid size can reduce optimization time and improve the quality of the solution. A. COORDINATE MODEL To ensure sufficient accuracy of the state information, an appropriate coordinate system must be established, comprising a global coordinate system and two local coordinate systems (Fig. 1): the global coordinate system XGOGYG, the robot-centered local coordinate system XRORYR, and the local coordinate system centered on the laser XLOLYL . The global coordinates of an obstacle are obtained from the following coordinate transformation:[ xg yg ] = [ \u03c1 cos |\u03b8 \u2212 \u03c0/2| + xe 0 0 \u03c1 cos |\u03b8 \u2212 \u03c0/2| + xe ] \u00b7 [ cos\u03d5 sin\u03d5 ] + [ x y ] (1) VOLUME 7, 2019 15141 here (xg, yg) are the coordinates of the obstacle in the system XGOGYG; (x, y) are the coordinates of the robot in the system XLOLYL ; xe is the distance between the coordinate originsOL andOR; \u03c1 and \u03b8 are respectively the polar distances and polar angle of the obstacle measured by the laser sensor" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003394_6514899_10230249.pdf-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003394_6514899_10230249.pdf-Figure12-1.png", + "caption": "FIGURE 12. Top view of robot in initial pose.", + "texts": [ + " Since the inchworm robot adds a transverse servo motor unit, the robot can achieve a steering gait. The inchworm robot has certain requirements for the space size to complete the steering gait. Next, we calculate the minimum space required for the inchworm robot to complete the steering. In order to show the steering motion process of the inchworm robot, we use the robot 's top view to describe the process. Based on the overall structure of the robot in Fig.4, the top view of the robot can be obtained as shown in Fig.12. When the robot is in the initial attitude S1, the steering process of the robot is shown in Fig.13. The inchworm robot turns the initial state as shown in the X1 pose in Fig.13, and there is a certain distance between the two suckers \ud835\udc510; when the robot performs a large-angle steering motion, the torso part will appropriately increase the step length of the step according to the steering angle to ensure that the two suckers will not collide with each other during the steering process. As shown in Fig", + " According to the attitude process of the robot steering, we derive the relationship between the steering angle and the distance between the two suckers as shown in Equation (16). { \ud835\udc37 = \ud835\udc371 + \ud835\udc371 \ud835\udc61\ud835\udc4e\ud835\udc5b \ud835\udefc + \ud835\udc371 \ud835\udc50\ud835\udc5c\ud835\udc60 \ud835\udefc \ud835\udc51 = \ud835\udc371 \ud835\udc60\ud835\udc56\ud835\udc5b \ud835\udefc \ud835\udc51 = \ud835\udc37 \ud835\udc60\ud835\udc56\ud835\udc5b \ud835\udefc \ud835\udc50\ud835\udc5c\ud835\udc60 \ud835\udefc 1+ \ud835\udc60\ud835\udc56\ud835\udc5b \ud835\udefc+ \ud835\udc50\ud835\udc5c\ud835\udc60 \ud835\udefc (16) The \ud835\udc371 in the equation (16) is the distance from the intersection point to the edge of the sucker, which is generated by the intersection of the position of the sucker on the steering center axis after steering and the position before steering in Fig.12, as shown in Fig.14. \ud835\udc37 is the side length of the sucker. From Equation (16), it can be obtained that the spacing \ud835\udc51 of the two suckers changes with the rotation angle \ud835\udefc. Under the condition that the distance between the two suckers \ud835\udc51 is the initial distance \ud835\udc510 and there is no collision during the steering process, the maximum steering angle of the steering motion can be obtained to be about 32\u00b0. When the steering angle exceeds 32\u00b0, the distance \ud835\udc51 between the two suckers will exceed the initial distance" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001937_00461_FULLTEXT01.pdf-Figure31-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001937_00461_FULLTEXT01.pdf-Figure31-1.png", + "caption": "Figure 31: Surface displacement of the test at a natural frequency of 0.82 p.u", + "texts": [ + "52 nm occurred at the end of the second foundation of the test bench. It increases at the end of the foundation, the displacement of the foundation, and the steel casing shown in black color in figure 30. The steel casing bends more than the foundation. The longitudinal strain of the left side casing is maximum along the negative x-axis. 49 At the second eigenfrequency 0.82 p.u, the maximum surface displacement of the hook bolt is 1.34 \u03bcm left side of the casing along the negative y-axis. The minimum displacement near to joint of left side of casing. Figure 31 shows maximum displacement at all the corners of the foundation and the tip of both casings. So, this frequency is crucial to avoid due to its twisting of the basement in the middle of the test bench. From figure 30,31 and 32, the study has been found that as the frequency increase from 0.46 to 1.57 p.u, the bending of the test bench foundation also increases. 50 5 Discussions 5.1 Automatic data processing of traction motor measured data discussion Another result shows that the PM magnet temperature data collected by the temperature logger in the study helps to understand the PM temperature trend with respect to time" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003332_f_version_1709110394-Figure18-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003332_f_version_1709110394-Figure18-1.png", + "caption": "Figure 18. Robot configuration with three omnidirectional wheels.", + "texts": [ + " In this configuration, three DC-geared motors are installed so that the steering axles match the geometric center of the chassis, with 120 degrees between each motor axis, as shown in Figure 17. For this purpose, the three motor supports should be oriented at 120 degrees and screwed, where another motor support and a DC-geared motor with another omnidirectional wheel replace the idler wheel. It is worth mentioning that now two linear velocities are presented for each wheel, vxi as the wheel longitudinal velocity, vyi as the wheel lateral velocity, and ui is the wheel angular velocity for i = 1, 2, 3. Figure 18 depicts the new assembly configuration, which is described as follows: one encoder is added to the inputs, a motor is added to the outputs, and another H-bridge can be used to drive the third motor. Assumption 3. Note, that this type of robot also considers the Assumptions 1 and 2. Furthermore, it is worth mentioning that the distance LO is constant and orthogonal to the three wheels, and the three distances match the geometric center of the robot\u2019s chassis. Figure 19 illustrates the robot\u2019s attitude concerning the inertial frame xI \u2212 yI " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004741_tr_pdf_ADA595226.pdf-Figure15-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004741_tr_pdf_ADA595226.pdf-Figure15-1.png", + "caption": "Figure 15 - Inflation diagram", + "texts": [ + " The glass aids in evaluating troublesome situations to clearly verify any problems in challenging pipe geometries (Figure Figure 12, Figure 13 and Figure 14). Page 13 of 47 During testing, unrestricted expansion of the bladders decreased resultant axial force. A new \u2018X\u2019 wing design was developed to constrain bladder inflation and provide bearing surfaces during motion and help center the module in the pipe. The \u2018X\u2019 shaped skid allows the silicone tubing of the grippers to inflate in a controlled geometry which decreases inflation/deflation times (Figure 15). A gripper snout was developed for both the front and rear of the robot to aid in smoother motion of the gripper around curves, tees, elbows, etc. (Figure 16). Page 14 of 47 The new design allowed for higher pressure which allowed the gripper to achieve 30lbs of axial force (Figure 17). Based on the success of the new \u2018X\u2019 wing design a second set of parts were fabricated. A printed circuit board (PCB) assembly was designed and built to facilitate remote control of the robot. This module is composed of two PCB assemblies; a controller and a valve driver" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000371_e_download_3204_2352-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000371_e_download_3204_2352-Figure2-1.png", + "caption": "Fig. 2. Complete system of computer vision", + "texts": [ + " It also has a light source, in the form of a ring of bulbs to achieve a diffused light form. To manage the computer vision system (Fig. 1), a stepper motor was developed, which will allow automatic focus movement, to have a more precise movement [11, 12]. The proposed stepper motor is a bipolar permanent magnet motor; this design is 4 coils. The operation is very simple. The rotor is fixed in the middle of the stator, when the polarity of one of the stator poles changes, then the magnet aligns itself according to the polarity. The developed prototype is demonstrated in Fig. 2. There were two aluminum tubes, a webcam, a PVC mount for the webcam, a thin lens with a focal length of 8.4 cm for which a PVC mount was also developed. A diaphragm was developed to limit light rays from external sources, a base for the device and a light source, formed by a ring of 12 V bulbs to obtain a diffused light. Autofocus by contrast evaluation is based on the principle that an out-of-focus image has lower contrast, while a focused DEVELOPMENT AND ANALYSIS OF COMPUTER VISION SYSTEM FOR MICROMECHANICS Tetyana Baydyk Corresponding author Department of Micro and Nanotechnology1 t" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000633_77754_FULLTEXT01.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000633_77754_FULLTEXT01.pdf-Figure4-1.png", + "caption": "Figure 4: Double horseshoe (Brown 1892)", + "texts": [ + " As with the materials, the shape of horseshoes has also changed through the history. Henry Burden in the United States patented the first horseshoe-manufacturing machine in 1835. This machine could produce a maximum of 60 pieces per hour. Although it is unknown who invented the first horseshoe a few years later in 1861, J.B. Kendall patented the first composite horseshoe. Some years later, Oscar E. Brown invented the double horseshoe in 1892. This horseshoe was composed of two pieces, which are displayed in Figure 4 (piece 1 and piece 2). One of these pieces was the upper shoe (piece 1), which was attached directly to the hoof of the horse. The other piece (piece 2) could be attached to the upper shoe and it could be removed if it was necessary. The aim of this horseshoe was to obtain a faster change of horseshoes without needing to remove it completely. 5 The main functions of the horse\u00b4s hoof are to support the weight of the horse, to absorb shock against the ground, to provide traction to the horse and to permit the blood flow explained above; therefore, the objective of horseshoes is to supply these functions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000224_LobsterMechanics.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000224_LobsterMechanics.pdf-Figure4-1.png", + "caption": "FIGURE 4. Evaluation platform consisting of the pneumatic control circuit and data acquisition system, test rig and a 6-axis force/torque sensor.", + "texts": [ + " (5), (22), (21) and (19), an explicit relationship between output tip force and input pressure can be get as F = Ma \u2212M f ,max \u2212M\u03b8=0 l\u2217 = K1 l\u2217 Pin \u2212 K2 l\u2217 (20) where K1 and K2 are parameters only related to actuator geometry and friction limit, as discussed in section 3.3. To demonstrate the mechanical performance of this proposed hybrid actuator and validate the proposed analytic model, hybrid actuators with six configurations, from 7 to 12 segments, were fabricated and an evaluation platform was developed for the characterization tests. The platform (see Fig. 4) contained a 6-axis force/torque sensor which was mounted onto a three-axis adjustable aluminum frame to measure the force at the tip of the actuator. The measured data was displayed through a graphical interface (GUI) written in LabView. Pressure readings were obtained through a microcontroller (Arduino Mega) and displayed to the user to correspond the pressure in the soft actuator to the force it could produce. The hybrid actuator\u2019s proximal tip with air inlet was clamped in a rigid fixture, emulating a boundary condition as fixed" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003439_f_version_1668760308-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003439_f_version_1668760308-Figure2-1.png", + "caption": "Figure 2. Schematic representation of the measurement and compensation system.", + "texts": [ + " By precisely evaluating its design factors and appropriately raising the diameter of the rotor to grow the radial bearing area, the spindle can meet the requirements of a high bearing capacity, as well as high stiffness. The aerostatic lubrication makes the main shaft have a high rotation accuracy, extremely low friction coefficient, and low speed without creep [28]. By optimizing the selection of a larger air film thickness, the temperature increase due to the air film shearing is reduced. As a result, the machine tool can quickly reach thermal equilibrium at various speeds, and the influence of the machine tool\u2019s thermal errors on machining accuracy is decreased to a very low level. Figure 2 presents a schematic representation of the measurement and compensation system. Note that although the measuring system and cutting system are given in the same schematic diagram, they are not simultaneously implemented. Figure 3 illustrates a photograph of the diamond turning machine and the experimental setup exploited for the measurement. For ultra-precision machining, the magnitudes of the WRE and SREM are of the same order. According to the error separating principle, an in situ roundness measuring system by the 3-sensor approach is built up" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001863_f_version_1690282100-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001863_f_version_1690282100-Figure4-1.png", + "caption": "Figure 4. The shovel can perform two-degrees-of-freedom motion: namely, translational freedom along the x-axis and rotational freedom along the y-axis.", + "texts": [ + " The rotation speed and direction of the spiral roller can be adjusted to control its movement, while the mechanical bucket arm collects the garbage. By combining the spiral roller and the mechanical bucket arm, the robot can transport litter from the water surface to the shoreline. The robot can collect garbage from the sea surface and shoreline areas, transport it to a designated collection area, and continue executing instructions for garbage collection. Figure 3 presents the working schematic of the litter collection process, showing the movement of the bucket and the feeding motion of the garbage into the robot\u2019s garbage bin. Figure 4 displays the overall operational schematic, where an operator controls the robot via a PC terminal, for garbage collection from the sea surface and for onshore transportation. The cleaned garbage includes plastic waste, such as bottles, cans, and floating debris. The spiral drum has a historical background in coal mining, and it has undergone improvements by countries such as the United Kingdom, Germany, France, and the former Soviet Union. Initially used in coal cutting machines, the rotating spiral drum effectively excavates coal and transports it through internal conveyors or pipelines, significantly enhancing mining efficiency and reducing manual labor [38]", + " These two degrees of freedom work in tandem, enabling the shovel to move along the guide rails during garbage collection. By adjusting the tilt angle of the shovel, using the servomotor, the shovel can be rotated upwards by 120 degrees or more, allowing the garbage to be dumped into the robot\u2019s garbage collection box. This mechanism effectively achieves the function of garbage collection. For a visual representation of the mechanical-arm-type shovel\u2019s operation in garbage collection, refer to Figure 4, which illustrates the specific working schematic diagram. Given the robot\u2019s maritime and intertidal usage, waterproof performance is crucial. A waterproof box structure is adopted, consisting of a sealed waterproof garbage bin and a waterproof box for the main control board and chips. The box has two layers, with a hollow space for absorbent materials to provide protection in case of water leakage. The box is sealed with waterproof adhesive, to prevent water ingress, effectively protecting the robot\u2019s circuitry (Figure 5)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004210__download_22299_9453-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004210__download_22299_9453-Figure7-1.png", + "caption": "Fig. 7. Motor control circuit diagram.", + "texts": [ + "org Regarding the 24 volt and 350 Watt gear motor: when the motor control circuit delivers direct electric current to the motors as seen in Fig 6a, the motors will rotate according to the control kit controlled by facilitating two-directional rotation, namely, the clockwise direction and anticlockwise direction that facilitate the PWM system. The rotational speed adjustment is represented as a percentage according to commands of the motor control circuit. In this study, 2 units of motors mounted on the left rear wheel and right rear wheel were used, as seen in Fig 6b. As mentioned earlier, the hardware control of robot mobility was connected via electric circuits to control the mobility of the 2 motors that start from the direct connection of the motor control circuit to the microcontroller board, as seen in Fig 7a. In this study, the microcontroller board and DC motor driver board operating together with an Android smartphone application developed for voice commands were used to command the motors to work as required by using 12 V electricity to deliver electric current to the motors according to the circuit diagrams, as seen in Fig 7b. (a) iJOE \u2012 Vol. 17, No. 06, 2021 29 Data transmission: the wheelchair and the input device will be connected to the signal Wi-Fi network. Wi-Fi is distributed from the input device, causing the input device to act as a router device. When the system installed in the wheelchair is opened, the system will connect to the client device via Wi-Fi network as shown in fig. 8. 30 http://www.i-joe.org As shown in figure 8, the systems are connected together on the same Wi-Fi network. The microcontroller board receives voice commands from the input device to process and send the processed voice commands to control the movement of the robot" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004999_197h44r_fulltext.pdf-Figure4.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004999_197h44r_fulltext.pdf-Figure4.1-1.png", + "caption": "Figure 4.1: Illustrates Husky Reduced-Order Model (HROM)", + "texts": [], + "surrounding_texts": [ + "CHAPTER 3. HUSKY-\u03b2 PLATFORM\n25", + "Chapter 4\nWe use a reduced-order model, called HROM, for the collocation-based control design.\nIn the HROM, each leg is assumed to be massless, that is, all masses are incorporated into the body yielding a 6-DOF model representing the torso\u2019s linear and orientation dynamics. Each leg is modeled using two hip angles (frontal and sagittal) and a prismatic joint to describe the leg end\n26", + "CHAPTER 4. HUSKY CARBON MODELING\nposition. In HROM, the thruster forces are applied to the body center of mass (COM) and the ground reaction forces (GRF) are applied at the foot end positions.\nLet the superscript b represent a vector defined in the body frame (e.g., ab), and the rotation\nmatrix Rb \u2208 SO(3) represents the rotation of a vector from the body frame to the inertial frame (e.g., a = Rba b). As such, the foot-end positions in the HROM can be derived using the following kinematics equations: pfi = pb +Rbl b hi +Rbl b fi\nlbfi = Ry (\u03d5i)Rx (\u03b3i) [ 0, 0, \u2212ri ]\u22a4 ,\n(4.1)\nwhere pfi and pb denote the world-frame position of leg-ends and body position, respectively. lbhi and lbfi denote the body-frame position of hip-COM and foot-hip, respectively. Rx and Ry denote the rotation matrices around the x- and y-axes. Finally, \u03d5i and \u03b3i are the hip frontal and sagittal angles respectively, and ri is the prismatic joint length.\nLet \u03c9b be the body angular velocity vector in the body frame and g denote the gravitational\nacceleration vector. The legs of HROM are massless, so we can ignore all leg states and directly calculate the total kinetic energy K = 1 2mp\u0307\u22a4b p\u0307b+ 1 2\u03c9 \u22a4 b Jb\u03c9b (where m and Jb denote total body mass and mass moment of inertia tensor). The total potential energy of HROM is given by V = \u2212mp\u22a4b g. Then, the Lagrangian L of the system can be calculated as L = K \u2212 V . Hence, the dynamical equations of motion are derived using the Euler-Lagrangian formalism.\n27" + ] + }, + { + "image_filename": "designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure53-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure53-1.png", + "caption": "Figure 53. Computer-aided drawing of an expanding wheel shown compressed and expanded.", + "texts": [ + " Prototype of present MFL test platform with non-magnetic Mecanum-type wheels to investigate horizontal moves. ERDC/ITL TR-19-2 48 To maximize platform positional accuracy and simplify control software, the platform should be capable of executing lateral moves. Other commercial research-and-development groups have come to the same conclusion, and some are turning to a complete second drive system to move magnetic crawlers laterally. Using the existing drive motors, an expanding wheel design is proposed (Figure 53), that will be placed perpendicular to the magnetic forward moving wheels. These expanding wheels can be forced open to lift the forward moving wheels and allow for lateral movement. With the expected mechanical advantage gained by the expanding wheel design, minimum effort would be required to lift the crawler from the magnetic surface. As little as 62 ounce-inches of torque per wheel is theorized to be adequate to lift the crawler from a steel surface. Water sealing of the Mobile Sensor Inspection Platform has been a major consideration from the start of this project; therefore, water sealing techniques have been studied and tested" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003325_8478841_08373731.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003325_8478841_08373731.pdf-Figure7-1.png", + "caption": "Fig. 7. Sketches of SoftHand 2 prototype. The red line in panel (a) highlights the tendon route. Panel (b) presents main components of SoftHand 2: (1) are the two motors, (2) are the four encoders, (3) is the control and power electronics. Panel (c) reports a 2-D section of the motor and encoder assembly. (a) Routing. (b) Exploded sketch. (c) Motor and encoder.", + "texts": [ + ", ri = r\u0304, Vi = V\u0304 \u2200i, E = k I), the following free closure configuration space results: Span \u23a7 \u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23a8 \u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23a9 \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a3 1 1 1 1 1 1 \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a6 , \u23a1 \u23a2\u23a2\u23a2\u23a2\u23a2\u23a2\u23a3 2 2 17 17 \u221219 \u221219 \u23a4 \u23a5\u23a5\u23a5\u23a5\u23a5\u23a5\u23a6 \u23ab \u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23ac \u23aa\u23aa\u23aa\u23aa\u23aa\u23aa\u23ad . (36) Thus, the net effect of this routing change is to leave the first direction unchanged, and to modify the second, reorganizing its elements. We present here the Pisa/IIT SoftHand 2, an anthropomorphic robotic hand evolving the Pisa/IIT SoftHand by the introduction of a friction mediated DoA. Fig. 6 shows the hand prototype, while Fig. 7(a) shows a sketch of the transmission system. Pisa/IIT SoftHand 2 has 19 joints. Five of them are simple revolute joints, and they implement the adduction/abduction movement of each finger. The remaining 14 joints are compliant rolling-contact element (CORE) joints [27] (see appendix A for more details). This choice strongly increases the hand robustness, such as the similarity between its kinematics and one of the human hands. Elasticity is introduced in each joint as discussed in Appendix B. A single tendon moves from the palm base, through all the fingers", + " Neglecting the four long fingers abduction joints (see Section V for more details) and considering a linear elastic field, the input directions of the two DoAs results from (20) as the span of [1, . . . , 1]TN and [33, 33, 33, 17, 17, 17, 1, 1, 1,\u221215, \u221215, -15, -31, -31, -31]TN. As prescribed by (23), the freeclosure configuration space is the span of [1, . . . , 1]T and [2, 2, 2, 1, 1, 1, 0, 0, 0, \u22121, \u22121, \u22121, \u22122, \u22122, \u22122]T , compatibly with physical joint limits. Thus, both closures are in line with the desired ones. We will test the ability of the proposed design to present such behavior through accurate simulations in the next section, and experimentally in Section VI. Fig. 7(a) and (b) shows two CAD views of SoftHand 2, with main components highlighted. The hand includes two MAXON DC-X 22 s 24 V motors, mounted on the back. We also included 86:1 gearboxes, characterized by 15 W of continuous output power. A single Dyneema tendon runs in the whole hand. The motor positions are acquired using magnetic sensors from Austrian Microsystem. Two encoders are included for each motor, as depicted in Fig. 7(b). This choice is due to the necessity of having an absolute measurement of motor angles, robust to possible unexpected switching OFFof the electronics. The number of tics of the two encoders is selected to be coprime. The absolute angle is then derived integrating the two measurements through the Chinese remainder theorem [33]. The firmware is implemented on a custom electronic board, mounted on the bottom part of the hand. Its schematics are openly released, and they are available online as part of the Natural Machine Motion Initiative [34]", + " They are kinematically equivalent to an RR arm, with a virtual (i.e., no inertia) intermediate link with an equality constraint between the two joint angles [see Fig. 23(a) and (b)]. Hence, the 4-joint robotic finger dynamics is equivalent to a 7R arm with standard kinematics, plus three equality constraints, which reduce the DoFs to 4. This model describes index, middle, ring, and little fingers of the Pisa/IIT SoftHand. The thumb differs slightly, since it has one phalanx less and the abduction axis is oriented differently (see Fig. 7). Fig. 24 shows a schematic representation of interphalangeal elastic mechanism. The spring characteristic is considered linear. The spring deflection w.r.t. qi is 2Ri(cos (\u03b2i + qi) \u2212 cos (\u03b2i)). Gear envelope radius Ri is considered constant. The angle of the spring connection with respect to the segment connecting the envelope centers is referred as \u03b2i . Resulting spring energy is E(q) = 4\u2211 i=2 2kiR 2 i (cos (\u03b2i + qi) \u2212 cos (\u03b2i))2 . (45) The interphalangeal elastic field Gi(q) is Gi(q) = 4 ki R2 i (cos (\u03b2i) \u2212 cos (\u03b2i + qi)) sin (\u03b2i + qi)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003161_f_version_1657709863-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003161_f_version_1657709863-Figure12-1.png", + "caption": "Figure 12. Control sequence of each joint of manipulator.", + "texts": [ + " When the contact signal appears as the manipulator approaches the target object, the mechanical finger bends to the specified initial bending value according to the signal generated in different situations. The contact signals here can be divided into three categories, the first of which is the palm- type power grip contact signal. In this case, the data M of the pressure sensor at the palm is used as the trigger symbol, and when M is unequal to 0, the contact has been triggered. According to the law of hand grasping, the manipulator successively bends the MCP, PIP, and DIP, and the control sequence of each joint is shown in Figure 12. The second category is the power grasp of the proximal interphalangeal joint, with the pressure signal MP of i re 11. xternal interaction perception based on accel ration. (a) The hand maintains static or e at a uniform speed. (b) Collision with obstacles located in the Y and Z axes. (c) The change i Z-axis acceleration when the object is being placed on the table. According to the analysis and relevant conclusions in the preceding sections, the control and planning of manipulator grasping are carried out based on the understanding of manual grasping mechanism", + " An obstacle collision was estimated to have occurred when the accelera- tion in ax, ay is greater than the collision threshold, and then the path is re-planned in reverse motion in accordance with the original motion direction of the manipulator. All the above control selection and planning processes are presented in Figure 13 clearly. The overall planning is mainly based on the tactile sensing and position perception system, analyzing and summarizing the mechanism, as well as characteristics of the human hand grasping and mapping to the manipulator grasping. Figure 12. Control sequence of each joint of manipulator. After the mechanical finger makes full contact with the object, the surface force will be sensed through the FSR pressure sensor. According to the research in Section 3.1, there is a certain correlation between the forces of the three joints in a stable grasping state. The pressure decreases sequentially from the distal phalangeal joint to the metacarpal joint, which can be used as an initial judgment for attempted grasping. Once the joint force meets the initial grasping criteria, the robotic arm moves upward, and the manipulator tries to grab objects" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003096_8600701_08610222.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003096_8600701_08610222.pdf-Figure1-1.png", + "caption": "FIGURE 1. 2-DOF robot manipulator scheme.", + "texts": [ + " Then, according [30, Lemma 1], three dominant real roots are placed at \u03c3i = \u03c3 \u2217i and the maximal exponential decay rate \u03c3 \u2217 is reached, if the control parameters are selected as follows: \u03c3 \u2217i = \u03b4i\u03bdi + \u221a \u03bd2i (1\u2212 \u03b4 2 i )+ \u03ba\u0303i, (22) and, the gain values kPi, kRi and delay Ti of the input torque (16) are: kPi = \u03bd2i + \u03ba\u0303i, (23) VOLUME 7, 2019 13991 Ti = 1\u221a \u03bd2i (1\u2212 \u03b4 2 i )+ \u03ba\u0303i , (24) kRi = 2(\u03c3 \u2217i \u2212 \u03b4i\u03bdi) Tie\u03c3 \u2217 i Ti . (25) IV. DYNAMIC MODEL AND CONTROLLER DESIGN This section is devoted to provide the dynamic equations of a 2-DOF planar robot manipulator. Also the proposed design methodology for the PD+G and PR+G control schemes to perform tracking trajectories tasks is presented. A. DYNAMIC MODEL OF 2-DOF MANIPULATOR ROBOT In Figure 1 a schematic of the planar robot under study is presented. Here, L1 and L2 represent the length of each link, l1 and l2 stand for the length of each center of mass, while m1 and m2 are the masses of the links, and their inertias are denoted as I1 and I2. The gravitational constant is g and finally \u03c41 and \u03c42 symbolize the control inputs. The generalized coordinates are given by the angular positions q = [q1 q2]T and the dynamic model of the robot manipulator is given as follows: M(q)q\u0308+ C(q, q\u0307)q\u0307+G(q) = \u03c4 \u2212 Dq\u0307 (26) where \u03c4 = [\u03c41 \u03c42]T represents the generalized input torque vector and: M(q) = [ m11 m12 m21 m22 ] , where m11 = m1l21+m2L21+m2l22+2m2L1l2 cos(q2)+I1 + I2 m12 = m21 = m2l22 + m2L1l2 cos(q2)+ I2 m22 = m2l22 + I2, C(q, q\u0307) = [ \u22122m2L1l2q\u03072 sin(q2) \u2212m2L1l2q\u03072 sin(q2) m2L1l2q\u03071 sin(q2) 0 ] , G(q) = [ (m1l1 + m2L1)g sin(q1)+ m2l2g sin(q1 + q2) m2l2g sin(q1 + q2) ] , and D is the unknown matrix of the viscous friction and is of the form: D = [ d1 0 0 d2 ] " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002097_0.1145_192161.192200-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002097_0.1145_192161.192200-Figure3-1.png", + "caption": "Figure 3: Geometric details of the modelling of the iris.", + "texts": [], + "surrounding_texts": [ + "2\nROBOTIC SYSTEM Micro-surgery is currently performed by skilled surgeons often using hand crafted tools, where surgical intervention is limited by the dexterity of the surgeon and the available workspace. In the teleoperated micro-surgical robotic system currently being developed, a micro-surgical robot (MSR-1) will perform delicate eye operations under the guidance of a surgeon [8]. The micro-surgical system (see Figure 1) is composed of mechanical and visual master and slave subsystems. The surgeon grasps a handle (such as a micro-scalpel handle) which forms part of the micro-surgical mechanical master. Movements of this handle are monitored by six position transducers and fed to the master computer, where tremor is filtered prior to transmission to the slave computer which reproduces the same movement but scaled down by up to 100 times. The slave micro-surgical robot can hold a variety of micro-tools (diamond knives, probes etc). Forces measured by six transducers in the slave micro-surgical robot are scaled up and reflected back to the six actuators in the mechanical master which then exerts corresponding forces on the handle giving force feedback. The six-axis position/orientation of the surgeon's head (helmet) is used to control the slave stereo camera head. Stereo images from the slave cameras are transmitted back to the surgeon and displayed on either a head mounted display (HMD) or on a large high resolution video rear projection screen.\nThe modular nature of the Master-Slave arrangement allows the images and forces fed back to the master from the slave to be replaced (or aided) by visual and mechanical computer simulations. The virtual reality system replaces (or combines) the camera image with computer graphics generated from the eye model. Forces felt by the robot are determined using a finite element model of the tissue and are fed back to the operator via the force reflecting master. In this way both visual and mechanical simulation are achieved, with the surgeon using the same physical equipment as in an actual operation. The graphics can be displayed on either a stereo monitor, video projection screen or HMD.\nAs described in medical texts the eyeball can be considered as being composed of the segments of two slightly deformed spheres of different radii. It consists of three concentric layers which enclose its contents (see Figure 2): (1) The outermost fibrous layer maintains the shape of the eyeball and is called the sclera save for a transparent section at the front called the cornea which is the major area of refraction for light entering the eye. (2) The pigmented middle layer is vascular and nutritive in function and comprises the choroid, ciliary body and iris which is visible through the cornea. (3) The innermost layer is the retina, which consists of nerve elements and is the visually receptive area of the eye.\nThe eye has previously been modelled for computer graphics applications, mainly as part of facial models for animation sequences. Detail has usually been unnecessary because the face has been viewed from a distance, thus specific features of the eye have been simplified or omitted. The iris has normally been treated as a one or two colour annulus and the eyelids and eyelashes (if any) have been simple curves and surfaces, for example [9]. No reference has been found which models the interior of the eye.", + "3 The aim here was to produce a fast accurate 3-D model of the eye which holds its detailed appearance even on close up. We chose 10 Hz to be the minimum acceptable display rate for our initial virtual reality applications. It was necessary to make the model modular, so that aspects of the model, both graphical and analytical could be refined independently as development proceeded, and to allow aspects of the model to be animated such as making the eyelids blink, the eyeball rotate in its orbit and the pupil constrict or dilate. Another concern was to give the graphics generated from the model parametric complexity so that the same 'model' could be used for rendering at different speeds. Different levels of detail (LOD) can be individually assigned to components of the model. The above considerations led to a graphical modelling approach based on 3-D graphics primitives rendered by a workstation's graphics pipeline. Quite realistic images and lighting can be generated without the need for more versatile but more compute intensive rendering options such as ray tracing. A general view of the current model is shown in Figure 6. The eyeball can be seen together with the arrangement of the surface patches used to represent the skin.\nThe cornea is more highly curved than and protrudes from the sclera, which is white and smooth except where the tendons of the ocular muscles are attached. Both are displayed using relatively few polygons which are Gouraud shaded to produce a smoothed effect. For corneal surgery the specific geometry of a particular cornea will be obtained using laser based confocal microscopic imaging systems being developed for use in the micro-surgical robotic system [8].\nThe iris is the gemlike adjustable diaphragm around the pupil which controls the amount of light entering the eye. The colour of the iris ranges from light blue to very dark brown and is due to iridial connective tissue and pigment cells, which are often distributed irregularly producing a flecked appearance. The front surface of the iris can be divided into outer, ciliary, and inner, pupillary zones which often differ in colour and are separated by the collarette, a zigzag line, near which there are many pit like depressions called crypts. Representing the iris parametrically is difficult due to its complex colours and shapes. The approach adopted was to generate two layers (ciliary and pupillary) of wavy radial fibres with each fibre being a single Gouraud shaded polygon with six or more vertices and colours specified by a colour ramp. The co-radial fibre vertices were given slightly different colours to produce a 3-D curved effect. The ciliary fibres were bounded to the collarette which was generated using a periodic function. The ciliary fibre waviness was increased with Gaussian perturbations near the collarette resulting in the formation of crypts between opposed phases. When the pupil dilates in the model, the ciliary fibres become wavy. The pupillary fibres lie slightly below and have the greatest radial retraction. An alternative method that we have used to generate the iris has been to apply a texture map (from a close up photograph) to\nsignificantly fewer polygons. This speeds up the rendering of the iris on dedicated texture mapping hardware such as Silicon Graphics' Reality Engine. A disadvantage of this approach is that it does not allow the individual components comprising the iris to be manipulated as separate objects. We have chosen a combination of discrete object modelling and texture mapping depending on the level of object manipulation we require and the texture mapping performance of the workstation.\nThe retina is mainly soft and translucent. Near its centre is an oval yellowish area which has a central depression, the fovea centralis, where visual resolution is the highest. This area contains no retinal blood vessels. About 3 mm nasal to this area is the optic disc where the optic nerve joins the retina. The optic disc is slightly puckered and is pierced by the central retinal blood vessels. Usually pink but much paler than the retina, it may be grey or almost white. The general retinal hue is a bright terracotta red which contrasts sharply with the optic disc. The central retinal artery divides into two equal branches and again in a few mm, each branch supplying its own 'quadrant' of the retina. The central retinal vein is formed correspondingly. The branching of the artery is usually dichotomous with a 45 to 60 degree angle. Smaller lateral branches may leave at right angles. The vessels are visible as they lie close to the retinal surface. For retinal surgery, in order to accurately model the retina and retinal blood vessel distribution of a specific patient, it would be necessary to stereoscopically scan the retina obtaining 3-D retinal surface estimation and blood vessel form in a similar manner to [15]. At present we are focusing on corneal surgery and retinal and retinal blood vessel positional data are generated using a model which reproduces the fundamental anatomical features and allows the display method to be assessed. In the model of the fundus the retina has been represented as a deformed spherical segment containing the separately modelled optic disc on the posterior pole. The retinal blood vessels have been generated using a fractal tree [11] originating from the optic disc. The tree is projected onto the retinal sphere (see Figures 4 and 5). A recursive algorithm generated the vessel trees to a specified level of detail, subject to parameters describing mean branching angle, vessel radii and undulation, and creation of fine lateral vessels which branch from the main vessels at right angles. A repulsion factor was added in order to keep the large vessels from growing near the fovea centralis.", + "4\nAt the lowest LOD simple line segments are used. At the highest level, the vessels are represented by faceted cylinders replacing the line segments (depending on diameter). At middle levels Gouraud triangular prisms proved to be adequate.\nThe eyelids are two thin movable folds, adapted to the front of the eyes and forming an elliptical space when parted. The upper eyelid is larger and more mobile. On the nasal side the eyelids are separated by a triangular space, the lacus lacrimalis (tear lake), which contains a small elevation, the caruncle, and a reddish fold, the plica semilinaris. On the lateral side the eyelids meet at a more acute angle.\nRepresenting the shape of the surface of the skin around the eye presents several problems. There are large smooth areas of tissue, overlapping folds and areas of sharp curvature between the front and rear surfaces of the eyelids. Parametric complexity is desired and surfaces should be flexible and editable: during surgery the eyelids will be stretched open and fixed. Non-uniform rational B-spline (NURBS) surfaces were chosen to model the facial surface for several reasons: (1) Surfaces are represented with minimal data. Large data sets from patient facial scans may be reduced dramatically by the least squares fitting of a NURBS surface. (2) NURBS are implemented in hardware on several graphics workstations and evaluation is reasonably fast and stable. (3) They have a powerful geometric toolkit. The shape is controlled with control points and the continuity with knots. Refinement can be achieved by subdivision and knot addition. (4) The net formed by the control points approximates the surface. This allows for fast preliminary collision detection between the robot tools and the face. The initial geometrical data for a patients face is taken from a 3D surface scan. Because the resulting data currently does not give fine enough detail around the eye, and does not give the most efficient representation, a least squares NURBS surface fit of the data is made This represents the basic characteristic features, but with minimal data. An interactive NURBS facial surface editor was written to refine and manipulate the resulting surface. The refinements are made using anatomical data and pictures. Extra knots and control points were added around the eyelid area for fine control over the eyelids and lacus lacrimalis. The multiplicity of the knots along the rim of the eyelids was increased so that the curve between the front and rear faces could be sharpened." + ] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-6-1.png", + "caption": "Figure 9-6. Typical Driven Independent Suspension System for Wheeled Vehicle", + "texts": [ + " A simple geomet- 9-9 AMCP 706-356 ric construction reveals, for the conditions of no lateral movement of the tire at the ground, the ratio of: L h + S (9-1) Similar kinematic studies and additional kinetic investigations should be made for any proposed independent suspension layouts to incorporate the following desirable characteristics into, the system (a) minimum gyroscopic or inertia torques with vertical displacement, (b) minimum disturbance of the steering geometry with vertical displacement, and (c) favorable changes in whee' attitude, e.g., camber, during deflection caused by roll. 9-8 DRIVEN TYPES Driven, or powered, independent suspension systems can be utilized in the front or rear of wheeled vehicles. In the former case, a steering system must be incorporated into the total assembly in addition to the power transmission system. A driven, steerable independent suspension utilizing pivoted control links is shown in Figure 9-6. Typical of powered independent suspension systems is the location of the gear or differential ease shown in Figure 9-6. The power is transmitted to each wheel through half-shafts from the gear case which is attached to the sprung mass of the* vehicle. Since the gear box is fastened to the vehicle body or frame, the driving torque reactions do not affect the suspension springs as they do with the powered rigid (nonindependeiit) axle suspension system. Another important characteristic of the driven independent suspension system is the reduction in unsprung weight with respect to a comparable rigid axle system. Figures 9-7 and 9-8 show other arrangements of driven independent suspension systems" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000565_f_version_1587442673-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000565_f_version_1587442673-Figure4-1.png", + "caption": "Figure 4. Newton\u2013Euler Formulation for an arbitrary link in ijk coordinates.", + "texts": [ + " (8) The state-space system in Equation (8) can be used for both forward and backward recursions to obtain the generalized forces at the robot\u2019s joints. In the former, the higher motion variables are computed up to acceleration at the last link. This involves maneuvering the frames attached to each joint, i.e., from the base link up to the last link in the robot. On the other hand, generalized forces at each joint are modeled using the backward recursion. Thus, direct evaluations of the state-space system in Equation (8) are done in forward and backward recursions. Considering \u2112 in Figure 4 as an arbitrary link having its center of mass at \ud835\udc36 , if ?\u20d7? is a vector at joint \ud835\udc57 to joint \ud835\udc58 (\ud835\udc58 \u2236= \ud835\udc57 + 1) and aligns with \u2112 in magnitude and direction, ?\u20d7? can be described with respect to frame \ud835\udc56 at the robot\u2019s base (\ud835\udc56 \u2236= \ud835\udc57 \u2212 1). Thus, the forward kinematic model is obtained with the generalized DH matrix by taking \ud835\udc4e , \ud835\udf03 , \ud835\udefc , and \ud835\udc51 as parameters of link \ud835\udc3f in Equation (1). Since the coordinate systems of frames attached to the robot\u2019s links are orthonormal, any arbitrary point \ud835\udc5f along vector ", + " (8) The state-space system in Equation (8) can be used for both forward and backward recursions to obtain the generalized forces at the robot\u2019s joints. In the former, the higher motion variables are computed up to acceleration at the last link. This involves maneuvering the frames attached to each joint, i.e., from the base link up to the last link in the robot. On the other hand, generalized forces at each joint are modeled using the backward recursion. Thus, direct evaluations of the state-space system in Equation (8) are done in forward and backward recursions. Considering L j in Figure 4 as an arbitrary link having its center of mass at C j, if \u2192 u j is a vector at joint j to joint k(k := j + 1) and aligns with L j in magnitude and direction, \u2192 u j can be described with respect to frame i at the robot\u2019s base (i := j\u2212 1). Thus, the forward kinematic model is obtained with the generalized DH matrix by taking a j, \u03b8 j, \u03b1 j, and d j as parameters of link L j in Equation (1). Since the coordinate systems of frames attached to the robot\u2019s links are orthonormal, any arbitrary point \u2192 r j along vector \u2192 u j in frame k can be defined with respect to frame j using the relation ( j\u2192r j,k ) , as given in Equation (9), where iR j T and iP j are obtained using Equations (10) and (11), respectively: i\u2192r j,k = iR j T ( iP j ) = a j d jsin(\u03b1 j) d jcos(\u03b1 j) , (9) iR j = cos(\u03b8 j) \u2212sin(\u03b8 j)cos(\u03b1 j) sin(\u03b8 j)sin(\u03b1 j) sin(\u03b8 j) cos(\u03b8 j)cos(\u03b1 j) \u2212cos(\u03b8 j)sin(\u03b1 j) 0 sin(\u03b1 j) cos(\u03b1 j) , (10) iP j = a j cos ( \u03b1 j ) a jsin(\u03b1 j) d j) ", + " Thus, all are \ud835\udc43\ud835\udc5c\ud835\udc36 , ranked, the optimal tuple is selected as the one with the lowest \ud835\udc43\ud835\udc5c\ud835\udc36 , value, and the associated IK solution is utilized for the \ud835\udc43 \u2192 \ud835\udc43 movement in the operational plane. Examples of this case are the ash and red poses in Figure 5b. In cases with more than one obstacle, all \ud835\udc43\ud835\udc5c\ud835\udc36 , values could be greater than 0 where collision is just from a single link. Thus, the angle of the first revolute joint (\ud835\udf11) is re-computed to change the operational plane, viz. the black pose in the figure. 4. Implementation and Validation Results In this study, a typical \ud835\udc77 \ud835\udc79 \ud835\udc8f (n = 5) prototype of the snake-like robotic model in Figure 1 was simulated with the Robotics Toolbox [51] in Matlab (MathWorks, Inc., Natick, MA, USA). The flexible Figure 5. Analysis of the IK solution for obstacle (a) detection and (b) avoidance during motion planning. (a) Collision Detection Optimal mid and virtual points are needed to achieve a stable and collision-free point-to-point motion. Collision is analyzed in Figure 5a using a unique rotation axis of the robot\u2019s links in the workspace" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002434_f_version_1689397016-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002434_f_version_1689397016-Figure2-1.png", + "caption": "Figure 2. Establishment of spherical robot coordinate system: (a) spatial coordinate system of spherical robot; (b) projection of coordinate system on YAZA plane; (c) projection of coordinate system on XAZA plane.", + "texts": [ + "\u00a0Dynamic\u00a0Modeling\u00a0 The\u00a0dynamic\u00a0model\u00a0of\u00a0MMSPR\u00a0in\u00a0this\u00a0paper\u00a0is\u00a0based\u00a0on\u00a0the\u00a0following\u00a0assumptions:\u00a0 The dynamic model of MMSPR in this paper is based on the following assumptions: \u2022 During movement, MMSPR rolls without slipping, and its mass is decomposed into the mass of the shell and the pendulum: Ms, mp; \u2022 The centroid of MMSPR coincides with its geometric center; \u2022 The two degrees of freedom do not mutually interfere, and the longitudinal axis does not rotate. Appl. Sci. 2023, 13, 8218 4 of 17 The schematic diagram of MMSPR during rolling is shown in Figure 2a. Specifically, OA, OB, and OC represent the coordinate systems OA \u2212 XAYAZA, O\u2212 XBYBZB, and O\u2212 XCYCZC, and OA is the world coordinate system. OB is the coordinate system fixed at the geometric center of the sphere, which can only translate relative to OA. Additionally, OC is the coordinate system fixed at the geometric center of the sphere, which can only rotate relative to OA. R and L represent sphere\u2019s radius and the pendulum\u2019s length, respectively. \u03b8 and \u03c6 represent the rolling angles of MMSPR along its XB and YB", + " \u03b1 and \u03b2 refer to the rotation angles of the pendulum around the XB and YB. \u03c4x and \u03c4y are the driving torques acting on the XB and YB. Appl.\u00a0Sci.\u00a02023,\u00a013,\u00a0x\u00a0FOR\u00a0PEER\u00a0REVIEW\u00a0 4\u00a0 of\u00a0 17\u00a0 \u00a0 During\u00a0movement,\u00a0MMSPR\u00a0rolls\u00a0without\u00a0slipping,\u00a0and\u00a0its\u00a0mass\u00a0is\u00a0decomposed\u00a0into\u00a0 the\u00a0mass\u00a0of\u00a0the\u00a0shell\u00a0and\u00a0the\u00a0pendulum:\u00a0\ud835\udc40 ,\u00a0\ud835\udc5a ;\u00a0 The\u00a0centroid\u00a0of\u00a0MMSPR\u00a0coincides\u00a0with\u00a0its\u00a0geometric\u00a0center;\u00a0 The\u00a0two\u00a0degrees\u00a0of\u00a0freedom\u00a0do\u00a0not\u00a0mutually\u00a0interfere,\u00a0and\u00a0the\u00a0longitudinal\u00a0axis\u00a0does\u00a0 not\u00a0rotate.\u00a0 The\u00a0schematic\u00a0diagram\u00a0of\u00a0MMSPR\u00a0during\u00a0rolling\u00a0is\u00a0shown\u00a0in\u00a0Figure\u00a02a.\u00a0Specifically,\u00a0 \ud835\udc42 \u00a0,\u00a0 \ud835\udc42 \u00a0,\u00a0 and\u00a0 \ud835\udc42 \u00a0\u00a0 represent\u00a0 the\u00a0 coordinate\u00a0 systems\u00a0 \ud835\udc42 \ud835\udc4b \ud835\udc4c \ud835\udc4d , \ud835\udc42 \ud835\udc4b \ud835\udc4c \ud835\udc4d \u00a0,\u00a0 and\u00a0 \ud835\udc42 \ud835\udc4b \ud835\udc4c \ud835\udc4d ,\u00a0and\u00a0\ud835\udc42 \u00a0 is\u00a0the\u00a0world\u00a0coordinate\u00a0system.\u00a0\ud835\udc42 \u00a0 is\u00a0the\u00a0coordinate\u00a0system\u00a0fixed\u00a0at\u00a0the\u00a0 geometric\u00a0center\u00a0of\u00a0the\u00a0sphere,\u00a0which\u00a0can\u00a0only\u00a0translate\u00a0relative\u00a0to\u00a0 \ud835\udc42 .\u00a0Additionally,\u00a0\ud835\udc42 \u00a0 is\u00a0the\u00a0coordinate\u00a0system\u00a0fixed\u00a0at\u00a0the\u00a0geometric\u00a0center\u00a0of\u00a0the\u00a0sphere,\u00a0which\u00a0can\u00a0only\u00a0rotate\u00a0 relative\u00a0 to\u00a0 \ud835\udc42 \u00a0.\u00a0 \ud835\udc45\u00a0 and\u00a0 \ud835\udc3f\u00a0 represent\u00a0 sphere\u2019s\u00a0 radius\u00a0and\u00a0 the\u00a0pendulum\u2019s\u00a0 length,\u00a0 respec- tively.\u00a0 \ud835\udf03\u00a0 and\u00a0\ud835\udf19\u00a0 represent\u00a0 the\u00a0rolling\u00a0angles\u00a0of\u00a0MMSPR\u00a0along\u00a0 its\u00a0\ud835\udc4b \u00a0 and\u00a0 \ud835\udc4c .\u00a0 \ud835\udefc\u00a0 and\u00a0 \ud835\udefd\u00a0 refer\u00a0to\u00a0the\u00a0rotation\u00a0angles\u00a0of\u00a0the\u00a0pendulum\u00a0around\u00a0the\u00a0\ud835\udc4b \u00a0 and\u00a0 \ud835\udc4c .\u00a0 \ud835\udf0f \u00a0 and\u00a0 \ud835\udf0f \u00a0are\u00a0the\u00a0 driving\u00a0torques\u00a0acting\u00a0on\u00a0the\u00a0\ud835\udc4b \u00a0 and\u00a0 \ud835\udc4c .\u00a0 Figure\u00a02.\u00a0Establishment\u00a0of\u00a0spherical\u00a0robot\u00a0coordinate\u00a0system:\u00a0(a)\u00a0spatial\u00a0coordinate\u00a0system\u00a0of\u00a0spherical\u00a0robot;\u00a0(b)\u00a0projection\u00a0of\u00a0coordinate\u00a0system\u00a0on\u00a0 \ud835\udc4c \ud835\udc4d \u00a0 plane;\u00a0(c)\u00a0projection\u00a0of\u00a0coordinate\u00a0system\u00a0on\u00a0 \ud835\udc4b \ud835\udc4d \u00a0 plane.\u00a0 To\u00a0facilitate\u00a0the\u00a0controller\u00a0design,\u00a0MMSPR\u2019s\u00a0system\u00a0needs\u00a0to\u00a0be\u00a0decoupled.\u00a0Referring\u00a0 to\u00a0Kayacan\u00a0[24],\u00a0we\u00a0decoupled\u00a0the\u00a0robot\u00a0into\u00a0the\u00a0forward\u00a0motion\u00a0and\u00a0the\u00a0steering\u00a0motion\u00a0 (Figure\u00a0 2b,c).\u00a0 According\u00a0 to\u00a0 the\u00a0 Lagrange\u00a0 equation,\u00a0 taking\u00a0 the\u00a0 state\u00a0 variable\u00a0 \ud835\udc65 \ud835\udf03 \ud835\udefc \ud835\udf19 \ud835\udefd ,\u00a0the\u00a0dynamic\u00a0model\u00a0of\u00a0MMSPR\u00a0can\u00a0be\u00a0formulated\u00a0as:\u00a0 \ud835\udc40 \ud835\udc65 \ud835\udc61 \ud835\udc65 \ud835\udc61 \ud835\udc49 \ud835\udc65 \ud835\udc61 , \ud835\udc65 \ud835\udc61 \ud835\udc62 \ud835\udc61 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc40 \ud835\udc65 \ud835\udc65 \ud835\udc65 \ud835\udc65 \ud835\udc49 \ud835\udc49 \ud835\udc49 \ud835\udc49 \ud835\udf0f \ud835\udf0f \ud835\udf0f \ud835\udf0f \u00a0 (1)\u00a0 To facilitate the controller design, MMSPR\u2019s system needs to be decoupled. Referring to Kayacan [24], we decoupled the robot into the forward motion and the steering motion (Figure 2b,c). According to the Lagrange equation, taking the state variable x = [ \u03b8 \u03b1 \u03c6 \u03b2 ]T , the dynamic model of MMSPR can be formulated as: M(x(t)) .. x(t) + V ( x(t), . x(t) ) = u(t) M11 M12 M13 M14 M21 M22 M23 M24 M31 M32 M33 M34 M41 M42 M43 M44 .. x1.. x2.. x3.. x4 + V1 V2 V3 V4 = \u03c4x \u03c4x \u03c4y \u03c4y (1) Appl. Sci. 2023, 13, 8218 5 of 17 where: M11 = MsR2 + mpR2 + mpL2 + Is + Ip + 2mpRLcos(x2 \u2212 x1), M12 = \u2212mpL2 \u2212 Ip \u2212mpRLcos(x2 \u2212 x1), M13 = M14 = 0, M21 = \u2212mpL2 \u2212 Ip \u2212mpRLcos(x2 \u2212 x1), M22 = mpL2 + Ip, M23 = M24 = M31 = M32 = 0, M33 = MsR2 + mpR2 + mpL2 + Is + Ip + 2mpRLcos(x4 \u2212 x3), M34 = \u2212mpL2 \u2212 Ip \u2212mpRLcos(x4 \u2212 x3), M41 = M42 = 0, M43 = \u2212mpL2 \u2212 Ip \u2212mpRLcos(x4 \u2212 x3), M44 = mpL2 + Ip, V1 = mpRLsin(x2 \u2212 x1) " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003402_9668973_09664517.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003402_9668973_09664517.pdf-Figure3-1.png", + "caption": "FIGURE 3. The constraints decomposition of r1 and r2.", + "texts": [ + " Based on the principle of force equivalence, Fp2 can be equivalent to a force Fs which is parallel with Fp2 as well as passes through A2 and a torque T2 which is perpendicular with A2C and Fp2. Fs and T2 can be expressed as below: Fs = Fp2, Fs = Fp2 T2 = A2C \u00d7 Fp2 = (|A2C|R24)\u00d7 ( Fp2R23 ) = Fp2 |A2C| (R24 \u00d7 R23) (42) To find the deformations due to Ti, decompose Ti into two elements (i = 1, 2) [26], one is along ri (named Tip), and the other one is perpendicular to ri (named Tiq), as shown in FIGURE 3. Let \u03c42, \u03c4ip and \u03c4iq be the unit vector of T2, Tip and Tiq, respectively. Based on (4), it leads to: \u03c4 1p = \u03b41, \u03c4 1q\u22a5\u03c4 1p, \u03c4 1p\u22a5R12, \u03c4 1\u22a5R12, \u03c4 1q\u22a5R12, \u03c4 1q = \u03b41 \u00d7 R12\u03c4 2\u22a5R23, \u03c4 2\u22a5R24, \u03c4 2p = \u03b42, \u03c4 2q\u22a5\u03c4 2p, \u03c4 2q\u22a5R23, \u03c4 2q = \u03b42 \u00d7 R23 (43) According to (43), the value of Tip and Tiq (i = 1, 2) can be expressed as below: T1p = s1pT1, s1p = \u03c4 1 \u00b7 \u03b41 T1q = ( \u03c4 1 \u00b7 \u03c4 1q ) T1 = s1qT1, s1q = \u03c4 1 \u00b7 (\u03b41 \u00d7 R12) T2p = T2 \u00b7 \u03c4 2p = T2 \u00b7 \u03b42 = Fp2 |A2C| (R24 \u00d7 R23) \u00b7 \u03b42 = s2pFp2 s2p = |A2C| (R24 \u00d7 R23) \u00b7 \u03b42 T2q = T2 \u00b7 \u03c4 2q = T2 \u00b7 (\u03b42 \u00d7 R23) = Fp2 |A2C| (R24 \u00d7 R23) \u00b7 (\u03b42 \u00d7 R23) = s2qFp2 s2q = |A2C| (R24 \u00d7 R23) \u00b7 (\u03b42 \u00d7 R23) (44) where sip/siq (i = 1, 2) is a coefficient representing the relationship between the constrained forces/torques and their components" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000746_8600701_08740872.pdf-Figure17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000746_8600701_08740872.pdf-Figure17-1.png", + "caption": "FIGURE 17. The manipulator and two obstacles in physical space.", + "texts": [ + " On the other hand, fixing the task by adjusting the obstacle location or the manipulator base in the vertical direction outweighs those of the horizontal direction. D. MULTIPLE OBSTACLES Realizability of a path planning task in cluttered environment is of more interest in practice. For a given task, different obstacles may affect the task feasibility variously. In order to fix an unrealizable task, it is necessary to identify which obstacle prevents the task from being accomplished. The manipulator and its physical space is shown in Fig.17. The length of each link is 0.5m, and the coordinates of the manipulator base is (1, 1). Two circular obstacles are scattered in the environment. One obstacle with radius of 0.2m is centered at (1.3, 1.66), and the other with radius 0.15m is centered at (0.7, 1.4). Scopes for robot joint angles are 0 \u2264 \u03b81 \u2264 \u03c0 and 0 \u2264 \u03b82 < 2\u03c0 , respectively. The manipulator is assigned with three path planning tasks shown in Table 1. VOLUME 7, 2019 81537 The R-space is constructed with joint angles \u03b81 and \u03b82, the same as (11)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004907_f_version_1677146860-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004907_f_version_1677146860-Figure7-1.png", + "caption": "Figure 7. Schematic diagram of coordinate conversion.", + "texts": [ + " As shown in Figure 6b, the origin of the camera coordinate system is the optical center of the camera, and zc direction points in front of the camera, xc direction is the right side of the camera image, and yc direction points below the camera image. In addition, the coordinates under the camera coordinate system can be converted to the world coordinate system through rigid body transformation, including rotation transformation and translation transformation. Assume that the coordinates of the measured target center in the image coordinate system are (uo, vo) and (xc, yc, zc) are the coordinates in the camera coordinate system. Figure 7 shows the coordinate transformation diagram. The origin of the world coordinate system is the initial takeoff position of the UAV. Where d is the distance from the target to the optical center of the camera. According to the camera aperture imaging principle, d can be calculated with d = H f /h. And the value of d is equal to the depth of the depth camera Zc. Where h is the height of the target, H is the height of the tracking boundary box of the target in the image, and f is the focal length of the camera" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001304_82703_FULLTEXT01.pdf-Figure4.17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001304_82703_FULLTEXT01.pdf-Figure4.17-1.png", + "caption": "Figure 4.17. The second iteration design, side view to show side-cutout.", + "texts": [], + "surrounding_texts": [ + "The component should be able to withstand temperature between -30\u00b0C to +60\u00b0C without any loss of function." + ] + }, + { + "image_filename": "designv7_3_0002061_6514899_10266320.pdf-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002061_6514899_10266320.pdf-Figure13-1.png", + "caption": "FIGURE 13: A Hexsoon EDU-450 quadcopter equipped with a Intel NUC, a Realsense D455 camera, an IMU, a battery and a flight controller.", + "texts": [ + " VOLUME 4, 2016 11 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ A. Milas: Autonomous UAV Exploration With Semantic Understanding of Indoor Environments Namely, for the simple warehouse scenario at r = 0.1 m the UAV traveled on average 43.59 m and 53.02 m by ASEP and MRF respectively, while at r = 0.2 m, 31.73 m and 39.43 m. VII. EXPERIMENTAL ANALYSIS A. SETUP For our outdoor experimental analysis, a Hexsoon EDU-450 quadcopter is used (Fig. 13) which features four T-motors HS2216 920KV motors attached to a carbon fiber frame. The dimensions of the UAV are 0.36 m \u00d7 0.36 m \u00d7 0.3 m, which makes it a relatively small UAV suitable for indoor environments. The total flight time of the UAV is around 8 min with a mass of m = 2.5 kg, including batteries, electronics and sensory apparatus. The Cube Orange+ flight controller unit is attached to the center of the UAV body, and it is responsible for the low-level attitude control of the vehicle. Furthermore, the UAV is equipped with an Intel NUC, i7-8650U CPU @ 1" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002619_2a313a8eec13cc12.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002619_2a313a8eec13cc12.pdf-Figure1-1.png", + "caption": "Figure 1: The two phases of the SMC [3].", + "texts": [ + " The designing of the SMC consists of two steps, (1) the construct of a sliding surface and (2) the construct of the control law. The Sliding Mode Controller consists of two phases [2], as explained below: A: Reaching phase: during this phase, the state trajectory is steering toward the sliding surface . In this phase, the system is sensitive to different types of perturbations. When the state trajectory arrived at the sliding surface another phase gets started called sliding phase, as shown in Figure 1. B: Sliding phase: during this phase, the state trajectory is forced to slide on the sliding surface and to move on this surface until it arrived at the origin as displayed in Figure 1. The general equation of control law is given by: (1) Where, is the equivalent control term responsible for steering the state trajectory of the system towards the sliding surface ( ) and is the discontinuous control term to constrainthe state trajectory to move straight on the surface until reaching the origin. The equation is given by [11]: ( ) ( ) (2) Where, is a constant gain with . The signum function ( ) is shown in Figure 2 below and is described as below [7, 13]: ( ) { (3) By substitute Eq" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure7-1.png", + "caption": "Figure 7: Stress distribution in medium carbon steel", + "texts": [], + "surrounding_texts": [ + "Comparision of maximum contact stresses for the three materials of spur gear i.e. grey cast iron, high carbon steel and medium carbon steel obtained from Hertz equation and ANSYS 12.1 is given in Table 3. Table 2. Comparision of maximum contact stresses obtained from Hertz equation and ANSYS 12.1 Supr Gear \u03c3\ud835\udc4e (MPa) Hertz Equation \u03c3\ud835\udc4e (MPa) ANSYS 12.1 Difference (%) Grey Cast Iron 231.58 233.89 0.987 High Carbon Steel 95.785 94.19 1.6 Medium Carbon Steel 113.42 113.33 0.07 http: // www.ijesrt.com \u00a9 International Journal of Engineering Sciences & Research Technology [327]" + ] + }, + { + "image_filename": "designv7_3_0001438_f_version_1529485659-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001438_f_version_1529485659-Figure1-1.png", + "caption": "Figure 1. Unfolding the side of a truncated cone-shaped link.", + "texts": [ + " Free electrons move in a regular direction to form the current under the action of the electric field force, which includes an electric current field. The electric field that accompanies the current field is excited by all charges in the space. If we want to maintain a constant current distribution, the charge density everywhere should be maintained and should not change with time. In this way, the potential value of every point in the electric field is known and unchangeable. According to geometry, the side of a truncated cone is an annular sector, as seen in Figure 1. The essence of wrapping a truncated cone-shaped link is to wrap the side of the truncated cone; hence, the shape of the proposed sensor is annular sectorial. Using the geometric properties of the annular sector, we established a polar coordinate system on the sensor, as shown in Figure 2. The parameters r1, r2 and \u03b80 in Figure 2 are adjustable based on the dimension of the target link. M(r, \u03b8) is the coordinate of the contact point under a polar coordinate system on the annular sectorial sensor, where r is the polar radius of M and \u03b8 is the polar angle of M" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000199_f_version_1611042768-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000199_f_version_1611042768-Figure1-1.png", + "caption": "Figure 1. Agent coordinate system.", + "texts": [ + " In this paper, we mainly focus on the 3D real-time trajectory planning of the kind of space-based robots, such as SPHERES [38] and astronaut assistant robots [39]. The agent can work in a space station or specific working range in which the flying distance is much shorter than the radius of the orbit. In addition, the algorithm can also be extended to other types of agent 3D trajectory planning. This section provides the mathematical model of the motion and the attitude of the spatial agent. In a 3D environment, the attitude of the agent is represented by the pitch angle \u03b8, yaw angle \u03c8, and roll angle \u03c6, as shown in Figure 1. Under reference coordinate system (Xf, Yf, Zf), the equation of the agent\u2019s motion is written as: X f (t+1) Yf (t+1) Z f (t+1) = X f (t) Yf (t) Z f (t) + \u2206t \u2217R f b vb x vb y vb z (1) where the \u2206t is the sampling time. The conversion between the reference coordinate system oXfYfZf and the body coordinate system oXbYbZb is in the order of 321. Therefore, the transformation matrix from the body coordinate system to the reference coordinate system is: R f b = c\u03c8c\u03b8 \u2212s\u03c8c\u03c6 + c\u03c8s\u03b8s\u03c6 s\u03c8s\u03c6 + c\u03c8s\u03b8c\u03c6 s\u03c8c\u03b8 c\u03c8c\u03c6 + s\u03c8s\u03b8s\u03c6 \u2212c\u03c8s\u03c6 + s\u03c8s\u03b8c\u03c6 \u2212s\u03b8 c\u03b8s\u03c6 c\u03b8c\u03c6 (2) where c and s are the cosine and sine, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004604_download_25463_10239-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004604_download_25463_10239-Figure9-1.png", + "caption": "Fig. 9. MLX90640-D55 distance between sensors and objects", + "texts": [ + " This engineering calculation gives us the maximum that the robot can measure and track abnormal body temperature. For example, if the pedestrian is inside the black spot area, the robot will stop moving, and the same if the pedestrian is outside the FOV area. \ud835\udc4b = 2000 \u2217 tan ( 55 2 ) = 1041\ud835\udc5a\ud835\udc5a (5) iJOE \u2012 Vol. 17, No. 11, 2021 111 We determine the FOV by the angle in each sensor sensitive radiation, which means the sensor detects if the object in FOV. To determine the distance between sensors and objects, we use equation (6), as shown in Figure 9. \ud835\udc37 = \ud835\udc46 2\u2217 \ud835\udc47\ud835\udc4e\ud835\udc5b( \ud835\udc39\ud835\udc42\ud835\udc49 2 ) (6) 112 http://www.i-joe.org This engineering estimate gives us the maximum amount that a robot can determine at a temperature level and at a level that tracks people. For example, if the object is within the empty spot area, the robot will stop moving, the same if the object is outside the observation field, as shown in Figure 10. The abnormal temperature was determined using a thermal camera. We utilize the I2C protocol to arrange the communication between the camera and the computer unit [33], [34], as shown in Figure 11" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003743_30457_FULLTEXT02.pdf-Figure2.7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003743_30457_FULLTEXT02.pdf-Figure2.7-1.png", + "caption": "Figure 2.7: Regenerative chatter caused by the interaction between the teeth of the tool and the workpiece [26]", + "texts": [ + " Frictional chatter: The slip-stick force between the tool and the workpiece can cause oscillations which are commonly called the \u201cdry friction\u201d response amongst machinists. Lubricating the system can minimize this effect and create stability. 2. Regenerative chatter: The most common and researched source of chatter for the past sixty years [26], this type of chatter is caused by the interaction of the approaching tooth and the wavy surface created on the workpiece by the returning tool as depicted in Figure 2.7. 3. Mode-coupling chatter: This type of chatter is caused by the coupling of two vibration modes during operation as portrayed in Figure 2.8 [27]. The system vibrates at the resonance frequency in this case, making mode-coupling chatter hard to distinguish from external force excitations of the system. 25 | Literature Review and Theoretical Background 4. Thermomechanical chatter: Induced by the thermal expansion and contraction of the tool or workpiece during machining processes, these effects often become more apparent when extreme operation parameters such as depth of cut are considered" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003007_d-Sutherland-PhD.pdf-FigureA-2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003007_d-Sutherland-PhD.pdf-FigureA-2-1.png", + "caption": "Figure A-2 Equivalent circuit model for DC motor.", + "texts": [ + " The extra versatility provided by DC motor control also comes at some cost in terms of ease of use. While servo actuators have an encapsulated positional control system, a robot using DC motors for actuation must implement its own positional, velocity or torque control systems. Regardless of the control scheme desired, implementation of control using DC motors is performed by regulating the input voltage to generate an output torque. The relationship between applied voltage and motor torque in a DC Motor can be described using the equivalent circuit model, shown in Figure A-2. [27] Motor torque is proportional to current: \u03c4motor = Kmotor I Back electromotive force is generated by shaft velocity: 346 Vemf = Ke \u03c9 Voltage induced by changing current: Vautoinduct= Lmotor ( dI/dt ) From the motor equivalent circuit model, we can say: Vapplied = I Rmotor + Vautoinduct + Vemf I = (Vapplied - Vemf - Vautoinduct) / Rmotor I = (Vapplied - Ke \u03c9 - Lmotor (dI/dt)) / Rmotor In a simplified model, Lmotor= 0 H: \u03c4motor = Kmotor (Vapplied - Ke \u03c9 ) / Rmotor \u03c4motor = f (Vapplied, \u03c9) Motor torque is a function of applied voltage and shaft velocity" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-FigureA.9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-FigureA.9-1.png", + "caption": "Figure A.9: Small round single cable sealers from Roxtec, Hilti and Cape Industries", + "texts": [], + "surrounding_texts": [ + "4. Conduct benchmarking and trendwatching for inspiration on possible solutions 5. Generate concepts 6. Evaluate the concepts through workshop 7. Generate/refine the concepts 8. Redo step 6 and 7 until satisfactory results 9. Start prototyping and testing Future work \u2022 As mentioned in the discussion regarding testing of prototypes, all three concepts needs to go through more iterations and further IP-testing to smooth out issues that has occurred and might occur, as well for more detailed and defined design choices \u2022 Interest from the market needs to be evaluated. The producer might see a value in modular products, but they wont be of value if their not sought after by the market \u2022 Further testing on IP, grounding, fire, etc needs to be done for proper certifications and market placement. New products are compared to old ones when deciding prices and what kind of application should be aimed at References [1] American Chemical Society, \u201cCas registry,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.cas.org/cas-data/cas-registry [2] K. L. Bariball and A. While, \u201cCollecting data using a semi-structured interview: a discussion paper,\u201d Journal of Advanced Nursing, vol. 19, no. 2, pp. 328\u2013335, Feb 1994, (Accessed May 29, 2024). [Online]. Available: https://pubmed.ncbi.nlm.nih.gov/8188965/ [3] K. Baylis, G. Zhang, and D. A. McAdams, \u201cProduct family platform selection using a pareto front of maximum commonality and strategic modularity,\u201d Research in Engineering Design, vol. 29, pp. 547\u2013563, Oct. 2018, (Accessed Dec. 18, 2023). [Online]. Available: https://doi.org/10.1007/s00163-018-0288-5 [4] W. S. Bisenius, \u201cIngress protection: The system of tests and meaning of codes,\u201d (Accessed June 29, 2024). [Online]. Available: https://web.archive.org/web/20 130522115323/http://www.ce-mag.com/archive/06/ARG/bisenius.htm [5] BTTG, \u201cReaction to fire,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.bttg.co.uk/testing/construction-products/reaction-to-fire/#:~: text=Overview,to%20their%20end%20use%20application. [6] CEN-CENELEC, \u201cEuropean standards,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.cencenelec.eu/european-standardization/european-sta ndards/ [7] DEJOND, \u201cL-profile - 30x30x3mm - sheets stainless steel 304,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.dejond.com/en/product/l-profile-3 0x30x3mm-sheets-stainless-steel-304 [8] DETASULTRA, \u201cCfs-t sbo transit frames,\u201d (Accessed June 27, 2024). [Online]. Available: https://en.detasultra.com/products/des-24 [9] S. D. Eppinger and T. R. Browning, Design Structure Matrix Methods and Applications. The MIT Press, 2012, (Accessed Dec. 18, 2023). [Online]. Available: https://ieeexplore.ieee.org/book/6267543 [10] G. Erixon, Design for Modularity. Dordrecht: Springer Netherlands, 1996, ch. Design for Modularity, pp. 356\u2013379, (Accessed March 04, 2024). [Online]. Available: https://link.springer.com/chapter/10.1007/978-94-011-3985-4_18 [11] \u2014\u2014, \u201cModular function development mfd, support for good product structure creation,\u201d in DS 53: Proceedings of the 2nd WDK Workshop on Product Structuring, vol. 2. Delft, The Netherlands: Delft University of Technology, June 1996, (Accessed March 04, 2024). [Online]. Available: 99 100 References https://www.designsociety.org/publication/28051/DS+53%3A+Proceedings +of+the+2nd+WDK+Workshop+on+Product+Structuring+1996%2C+Delf t+University+of+Technology%2C+the+Netherlands%2C+03.-04.06.1996 [12] \u2014\u2014, \u201cModular function deployment - a method for product modularisation,\u201d Ph.D. dissertation, The Royal Institute of Technology, 1998, (Accessed Dec. 18, 2023). [Online]. 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Available: https://www.icotek.com/sv/produkter/renrum-kabelgenomfoering /kel-er-cr [22] International Electrotechnical Commission, \u201cIngress protection (ip) ratings,\u201d (Accessed April 04, 2024). [Online]. Available: https://www.iec.ch/ip-ratings [23] J. v. Kistowski et al., \u201cHow to build a benchmark,\u201d in Proceedings of the 6th ACM/SPEC International Conference on Performance Engineering, ser. ICPE \u201915. New York, NY, USA: Association for Computing Machinery, 2015, p. 333\u2013336, (Accessed May 29, 2024). [Online]. Available: https://doi.org/10.1145/2668930.2688819 References 101 [24] K. Beck et al., \u201cThe 12 Principles behind the Agile Manifesto,\u201d (Accessed March 04, 2024). [Online]. Available: https://www.agilealliance.org/agile101/1 2-principles-behind-the-agile-manifesto/ [25] \u2014\u2014, \u201cWhat is the agile manifesto?\u201d (Accessed March 01, 2024). [Online]. Available: https://www.agilealliance.org/agile101/the-agile-manifesto/ [26] L. Baker Jr and J. E. Long, \u201cRole of system engineering across the system life cycle,\u201d Vitech Corporation, 2070 Chain Bridge Road, Suite 105 Vienna, Virginia 22182-2536, Tech. Rep., 2000, (Accessed May 29, 2024). [Online]. Available: https://vitechcorp-webdownload.s3.amazonaws.com/technical_pa pers/200701031632040.baker_long.pdf [27] D. McDonagh-Philp and A. Bruseberg, \u201cUsing focus groups to support new product development,\u201d September 2000, (Accessed May 28, 2024). [Online]. Available: https://api.semanticscholar.org/CorpusID:7103034 [28] MCT BRATTBERG, \u201cAlf cabinet seal,\u201d (Accessed June 27, 2024). [Online]. Available: https://www.mctbrattberg.com/product-catalog/cabinet-seals/alf-c abinet-seal/ [29] \u2014\u2014, \u201cRfcs cabinet seal - retrofit cabinet seal,\u201d (Accessed June 27, 2024). [Online]. Available: https://www.mctbrattberg.com/product-catalog/cabinet-s eals/rfcs-cs-cabinet-seal/ [30] Merriam Webster Inc., \u201cFrame definition Meaning,\u201d (Accessed Jan. 15, 2024). [Online]. Available: https://www.merriam-webster.com/dictionary/frame [31] R. Newcombe, \u201cFrom Client to Project Stakeholders: A Stakeholder Mapping Approach,\u201d Construction Management and Economics, vol. 21, no. 8, pp. 841\u2013848, Dec. 2003, (Accessed Jan. 15, 2024). [Online]. Available: https://doi.org/10.1080/0144619032000072137 [32] J. Pakkanen, T. Juuti, and T. Lehtonen, \u201cBrownfield process: A method for modular product family development aiming for product configuration,\u201d Design Studies, vol. 45, pp. 210\u2013241, 2016, (Accessed April 05, 2024). [Online]. Available: https://www.sciencedirect.com/science/article/pii/S0142694X16300 229 [33] Plastic Materials and Processes (PMP), \u201cEn 45545-2 \u2013 fire protection on railway vehicles,\u201d (Accessed May 28, 2024). [Online]. Available: https://pmpgro up.org/wp-content/uploads/2021/10/PMP-EN-45545-2-Railway-Standrad.pdf [34] M. G. Rekoff, \u201cOn reverse engineering,\u201d IEEE Transactions on Systems, Man, and Cybernetics, vol. SMC-15, no. 2, pp. 244\u2013252, 1985, (Accessed May 29, 2024). [Online]. Available: https://ieeexplore.ieee.org/abstract/document/6313 354/authors#authors [35] Roxtec, \u201cCrf 60x60/4 cm,\u201d (Accessed June 27, 2024). [Online]. Available: https://www.roxtec.com/en/products/solutions/roxtec-crf-transits/ [36] T. Rubber, \u201cCustom rubber extrusions and extruded rubber products,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.timcorubber.com/ rubber-capabilities/extruded-rubber-products/ 102 References [37] Seaview Progress, \u201cRetrofit cable seals,\u201d (Accessed June 27, 2024). [Online]. Available: https://www.seaviewprogress.com/en/webstore/seaview-elevate-ele ctronics/cable-seal/retrofit-cable-seals/ [38] Solar, \u201cKantlist sz kant,\u201d (Accessed May 28, 2024). [Online]. Available: https://www.solar.se/se-webshop/automation/apparatlador-och-skap/accessor ies-for-distribution-board/component-for-wiring-cable-entry-cable-fixing-enclo sureswitchgear-cabinet/1000522577/ [39] D. V. Steward, \u201cThe design structure system: A method for managing the design of complex systems,\u201d IEEE Transactions on Engineering Management, vol. EM-28, no. 3, pp. 71\u201374, 1981, (Accessed Dec. 18, 2023). [Online]. Available: https://ieeexplore.ieee.org/document/6448589 [40] Z. Varvasovszky and R. Brugha, \u201cA stakeholder analysis,\u201d Health Policy and Planning, vol. 15, no. 3, pp. 338\u2013345, Sept. 2000, (Accessed Jan. 15, 2024). [Online]. Available: https://doi.org/10.1093/heapol/15.3.338 [41] WallMax, \u201cRectangular metal frames - wmf,\u201d (Accessed June 27, 2024). [Online]. Available: https://www.wallmax.it/product/wmf/ [42] \u00d8ystein Eggen, \u201cModular product development,\u201d Norwegian University of Science and Technology - Department of Product Design, Tech. Rep., 2002, (Accessed March 4, 2024). [Online]. Available: http: //alvarestech.com/temp/PDP2011/CDAndrea/Gerenciamento%20da%20a rquitetura%20do%20produto/PROJETO%20MODULAR.pdf Appendix A Supplemental Information 104 Appendix A. Supplemental Information 105 106 Appendix A. Supplemental Information 107 108 Appendix A. Supplemental Information 109 110 Appendix A. Supplemental Information 111 112 Appendix A. Supplemental Information 113 114 Appendix A. Supplemental Information 115 116 Appendix A. Supplemental Information 117 118 Appendix A. Supplemental Information 119 Grand tour \u2022 Finns det n\u00e5got/n\u00e5gra problem med tillverkningen/designen av produkterna som du m\u00e4rkt av? \u2022 Finns det funktioner i produkterna som du tycker saknas? \u2022 Vilka problem har uppst\u00e5tt som motiverar en modul\u00e4r produkt? \u2022 Varf\u00f6r blir det dyrt att \u00e4ndra h\u00e5ldimensioner? G\u00e4ller det strikt efterarbete eller \u00e4r det andra faktorer som p\u00e5verkar? \u2022 Vad h\u00e4nder d\u00e5 kraven p\u00e5 produkten fr\u00e5n kunden \u00e4ndras n\u00e4ra inp\u00e5 leverans/tillverkningsprocessen? \u2022 Finns det n\u00e5got s\u00e4rskilt som kunder har \u00f6nskat ang\u00e5ende ytterligare funktioner och design p\u00e5 era produkter? Reflection \u2022 Summera lite av vad som sagts. \u2022 \u00c4r det n\u00e5got du skulle vilja till\u00e4gga? Faculty of Mechanical Engineering, Blekinge Institute of Technology, 371 79 Karlskrona, Sweden" + ] + }, + { + "image_filename": "designv7_3_0001309_f_version_1698070838-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001309_f_version_1698070838-Figure1-1.png", + "caption": "Figure 1. Design of greenhouse self-balancing mobile robot. Note: components, No.: 1. three-degrees-of-freedom wheel-leg; 2. human\u2013machine interface; 3. robot frame; 4. control cabinet; 5. wheel-leg shell; 6. flexible joint sensor shell; 7. wheel-leg drive unit shell; 8. wheel hub.", + "texts": [ + " In this section, we will provide a detailed introduction to the design of the greenhouse self-balancing mobile robot developed in this study. 2.1. Design Scheme and Working Principle of Self-Balancing Mobile Robot in Greenhouse The four-wheel layout can balance flexibility and stability; therefore, this paper designed a self-balancing mobile robot for facility harvesting based on the four-wheel layout, which is mainly used for facility agriculture harvesting and transportation. The structure of the facility harvesting self-balancing mobile robot is shown in Figure 1. The greenhouse self-balancing mobile robot mainly consists of a self-balancing control system, a three-degrees-of-freedom wheeled-leg system, and a walking control system. The threedegrees-of-freedom wheel-leg is primarily responsible for the robot\u2019s walking mode and robot posture control. The casings of the wheel-leg, flexible joint sensor, and wheel-leg drive unit are mainly designed to protect the motors and sensors from damage. Agriculture 2023, 12, x FOR PEER REVIEW 3 of 29 the stable state of the robot platform is easily disrupted, which can have an impact on other operational equipment", + " In this section, we will provide a detailed introduction to the design of the greenhouse self-balancing mobile robot developed in this study. 2.1. Design Scheme and Working Principle of Self-Balancing Mobile Robot in Greenhouse The four-wheel layout can balance flexibility and stability; therefore, this paper designed a self-balancing mobile robot for facility harvesting based on the four-wheel layout, which is mainly used for facility agriculture harvesting and transportation. The structure of the facility harvesting self-balancing mobile robot is shown in Figure 1. The greenhouse self-balancing mobile robot mainly consists of a self-balancing control system, a three-degrees-of-freedom wheeled-leg system, and a walking control system. The threedegrees-of-freedom wheel-leg is primarily responsible for the robot\u2019s walking mode and robot posture control. The casings of the wheel-leg, flexible joint sensor, and wheel-leg drive unit are mainly designed to protect the motors and sensors from damage. Figure 1. Design f ree se self-balancing mobile robot. Note: compone ts, No.: 1. three-degreesof-freedom wheel-leg; 2. human\u2013 chine interface; 3. robot frame; 4. control cabinet; 5. wh el-leg s ll; 6. flexible joint sens r shell; 7. w el-leg drive unit shell; 8. w el hub. The three degrees of freedom of the three-degrees-of-freedom wheeled-leg system are responsible for driving, steering, and balancing, as shown in Figure 2a. A single threedegrees-of-freedom wheeled-leg system has three drive motors, which are the leveling control motor(china), steering motor(china), and walking motor(china)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.20-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.20-1.png", + "caption": "Figure 4.20 Fork Horizontal Movement of the Forks", + "texts": [ + "10 Front View of Scissor Lift with Maximum Lifting Range (P60) Figure 4.11 Collapsed View of Lifting Fork Assembly (P61) Figure 4.12 Exploded View of lifting Fork Assembly (P62) Figure 4.13 Overview & Dimension of Fork Lid (P63) Figure 4.14 Overview & Dimension of Fork Support Frame (P64) Figure 4.15 Overview & Dimension of Rack Axle (P65) Figure 4.16 Overview & Dimension of Rack Fixer (P65) Figure 4.17 Overview & Dimension of the Fork (P66) Figure 4.18 Overview & Dimension of Spur Gear (P67) Figure 4.19 Overview & Dimension of Rack Motor (P67) Figure 4.20 Fork Horizontal Movement of the Forks (P68) Figure 4.21 Vertical Movement of the Forks (P69) Figure 4.22 Rotation of the Forks (P69) Figure 4.23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4.25 Overview & Dimension of the Steering Wheel (P71) Figure 4.26 Overview & Dimension of Chassis (P72) Figure 4.27 Overview & Dimension of Counterweight (P73) Figure 4.28 Overview & Dimension of Mast 1 (P74) Figure 4.29 Overview & Dimension of Mast 2 (P75) Figure 4", + "12 Exploded View of lifting Fork Assembly Overall there are 9 different components designed here. Figure 4.13 \u2013 Figure 4.19 are the isometric view and engineering drawings of 7 of them. The motor used here is a standard part, not designed specifically. All parts\u2019 dimensions are introduced here as well. (a) Isometric View Movements of lifting fork can be simplified as three basic motions: horizontal, vertical and rotation. Here we will use the lifting fork assembly and the cabin to demonstrate them. First, the forks are at resting position as in Figure 4.20a shows. The forks usually rest on one side of the truck (depending on which side of aisle the load is sitting and the fork will be on the other side waiting for the next move). In this case it is on the left side of the truck. After the forklift reaches the cargo, the forks will move forward in order to go under the cargo, as Figure 4.20b shows. The arrow indicates the forks move to the right of the truck. When those forks reach under the cargo, part of the fork assembly, including forks, the support frame and fork lid, will move up to lift the load up, see Figure 4.21. After the load is picked up, the forks will retreat to its middle position as shown in Figure 4.22a. At this point, the cargo has completely been moved away from the shelf and resting on those forks. Then the fork support frame makes a 90\u00b0 turn to make the cargo face in front as in Figure 4" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001452_onf_er2017_02004.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001452_onf_er2017_02004.pdf-Figure3-1.png", + "caption": "Fig. 3. Model of a moving platform with pendulum.", + "texts": [ + " The method of overcoming the \"distance\" between the theory of adaptive and robust control with the practice of its application, based on the transition to multialternative systems, is considered in [17]. The ideas of multi-alternativeness have biological analogies, defined in W. Ashby\u2019s Law of Requisite Variety [18], and also correspond to fuzzy control procedures of L. Zadeh [19]. The authors regard the inverted pendulum model as a typical member of structurally unstable objects. The model is fixed on the platform moving in a horizontal plane with some friction under the action of the external force (Fig. 3). The movement of an unstable object is given as: ( + )x \u2212 (\u03b1cos\u03b1 \u2212 \u03b1 sin\u03b1) = \u2212 = + ( \u2219 \u2212 xsin\u03b1 \u2212 \u03b1 )sign(x)\u2212xcos\u03b1 + \u03b1 \u2212 gsin\u03b1 = 0 , (8) where m1, m2 are the masses of platform and inverted pendulum, kg; L is the length of pendulum, m; \u0445 is the coordinate of platform\u2019s horizontal location, \u03b1 is the lack of perpendicularity angle, rad; g is the acceleration of gravity, m/s2; \u03c9 is the angular rate, rad/sec; \u00b5 is a dry friction coefficient of the platform; Ffr is the dry friction force, N; F is the imposed force to the platform, N" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003014_)_2022_1029-1041.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003014_)_2022_1029-1041.pdf-Figure3-1.png", + "caption": "Figure 3: Shelf support with machined features in red.", + "texts": [ + " They could be used to adapt the process parameters, such as torch distance, welding power, travel speed of the torch, speed of the wire, etc\u2026, according to pre-elaborated bead formation models and correction strategies. Such strategy could be conveniently based on Machine Learning (ML) algorithms which have been trained based on an extensive experimental campaign [7]. This section presents a test case to highlight the steps of the proposed process and how they should be addressed to fully exploit the developing process. The considered test case is a support for large and heavy shelf (Fig. 3). This bracket is composed of a base and four links. The base is hold to the wall by three screws or studs. Also, the longer links have two holes for fixing. The bounding box measures are 755 x 425 x 365 mm and structural steel has been selected as material. According to Lockett in [27], this part is suitable for WAAM as it has a buy-to-fly ratio of 10 and its features are thicker than 2mm. Indeed, limited production batch does not justify standard forming technologies such as casting. Computer-Aided Design & Applications, 19(5), 2022, 1029-1041 \u00a9 2022 CAD Solutions, LLC, http://www.cad-journal.net However, some interfaces require a grade of precision stricter than WAAM can guarantee. Thus, in Fig. 3 the features that requires further machining are highlighted in red: the holes, the center cross cutout and the functional surfaces that are in contact with other bodies. So, the intermediate geometry manufacturable through WAAM is presented in Fig. 4. Focusing on the volume subdivision stage, it is possible to identify 9 sub-volumes by using concave loop extraction: the base, the 4 links and the supporting ends of the links. Next, the slicing trajectory needs to be identified for each sub-volume" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.33-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.33-1.png", + "caption": "Figure 4.33 Exploded View of Forklift", + "texts": [ + "23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4.25 Overview & Dimension of the Steering Wheel (P71) Figure 4.26 Overview & Dimension of Chassis (P72) Figure 4.27 Overview & Dimension of Counterweight (P73) Figure 4.28 Overview & Dimension of Mast 1 (P74) Figure 4.29 Overview & Dimension of Mast 2 (P75) Figure 4.30 Overview & Dimension of Tire (P76) Figure 4.31 Rendering Model of the Forklift (P77) Figure 4.32 Collapsed View of Forklift (P78) Figure 4.33 Exploded View of Forklift (P79) Figure 5.1 Mass Property of Truck Body (P81) Figure 5.2 Mass Property of Counterweight (P82) Figure 5.3 Mass Property of Operator Cabin (P82) Figure 5.4 Mass Property of Supporting Mast (P83) Figure 5.5 Mass Property of Subassembly: Lifting Fork (P83) Figure 5.6 Mass Property of Subassembly: Scissor Lift (P84) Figure 5.7 Mass Property of Forklift Assembly (P84) Figure 5.8 Mass Safety Zone of Forklift (P85) Figure 5.9 Front View of Forklift\u2019s Center of Mass (P86) Figure 5", + " This generates a more realistic image about how the forklift looks under its working condition. Figure 4.32 shows Figure 4.31 with the feature tree. As the feature tree shows on the left, there are 12 components (not including cargo) and two subassemblies. We have already introduced both subassemblies in previous section. The scissor lift pushes up the operator cabin alone with the lifting fork and the lifting fork in front of the truck is what the driver controls to pick up and drop all loads. Figure 4.33 is the exploded view if the forklift. It separates the forklift into 6 different major parts: the lifting fork in the front, the scissor lift, the operator cabin above it and the chassis under it, the supporting mast and the counterweight. The chassis is at the bottom, on top of it are scissor lift and operator cabin. The lifting fork system will be connected to operator cabin with its motors and the down rack fixer. They allow the system to move under the driver\u2019s control. During the loading process, the center of gravity will shift left or right, if the load is very heavy in which case it might cause the failure of the scissor lift" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004340_f_version_1690795198-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004340_f_version_1690795198-Figure4-1.png", + "caption": "Figure 4. Cont.", + "texts": [ + " Therefore, in order to predict the grasping range of the three ring-shaped soft grippers, FEM models were constructed to simulate the deformation of the inner wall of the three ring-shaped soft grippers, respectively. To simplify simulation and improve computational efficiency, the pneumatic inlets and pneumatic tubes were ignored. The surfaces of the top, bottom, and outside of the three ring-shaped soft grippers were constrained. The input air pressure varied from 0 kPa to 15 kPa at 1 kPa interval and applied on the inner surfaces of the air chambers. The contact between the inner wall was considered. As illustrated in Figure 4, the maximum deflection is used to indicate the degree of deformation of the inner wall; the deformation increases as the input air pressure increases, and the maximum deflection is at the central position of each inner wall. It is worth noting that the maximum deflection of the three-chamber ring-shaped soft gripper models (Figure 4b) is significantly larger than that of the two-chamber ring-shaped soft gripper models (Figure 4a) and the four-chamber ring-shaped soft gripper models (Figure 4c) under input air pressure from 4 kPa to 15 kPa. Biomimetics 2023, 8, x FOR PEER REVIEW 5 of 15 \ud835\udc4a \ud835\udc36 \ud835\udc3c 3 \ud835\udc36 \ud835\udc3c 3 (4) The defor ation range of the inner all deter ines the grasping range of the ringshape soft gripper; the larger the range of inner all efor ation, the larger the grasping ra e f t e ri -s a e s ft ri er. e ras i ra e is e f t e i rta t i exes f r s i rf r c f ri -s s ft ri r. r f r , i r r t r ict t i r e of the thr e ring-shaped soft grippers, FEM models were constructed to simulat the deformation of the inner wall of the three ring-shaped soft gripp rs, resp ctively", + " The surfaces of the t p, bottom, and outside of th three ring-shaped soft grippers were co strained. The input air pressure varied from 0 kPa to 15 kPa t 1 kPa interv l and applied o the inner urfac s of t e air chambers. The contact betwee the inner wall was considered. of the i ner wall; the deformation increases as the input air pressure in- creases, and the aximum deflection is at the central p sition of each inner wall. It is worth noting that the maximum deflection of the three-chamber ring- haped soft gripper models (Figure 4b) is significantly l rger than that of t e two-chamber ring-shaped soft gripper models (Figure 4a) and t e four-chamber ring-shaped soft gripper models (Figure 4c) under input air pressure from 4 kPa to 15 kPa. Biomimetics 2023, 8, 337 6 of 15Biomimetics 2023, 8, x FOR PEER REVIEW 6 of 15 Figure 4. The FEM results of the deformation of the inner wall of the three ring-shaped soft grippers at prescribed input air pressures. (a) Two-chamber ring-shaped soft gripper. (b) Three-chamber ring-shaped soft gripper. (c) Four-chamber ring-shaped soft gripper. 2.5. Finite Element Modeling of Contact Force The inner wall of the ring-shaped soft gripper expands and deforms under input air pressure, contacting the target object and resulting in contact force. We took the threechamber ring-shaped soft gripper as an example to study the relationship between its contact force and input air pressure. We used two cylinders (diameter 60 mm and 40 mm) as the grasping targets with PLA materials, the grasping targets were considered discrete rigid in FEM. For simplicity and intuition, the contact force between the inner wall of a single air chamber and the cylinder was analyzed (Figure 5a). The surfaces of the top, bottom, and outside of the FEM models were constrained. The finite element analysis results indicate the relationship between contact force and input air pressure, as shown in Figure 4. The FEM results of the deformation of the inner wall of the three ring-shaped soft grippers at prescribed input air pressures. (a) Two-chamber ring-shaped soft gripper. (b) Three-chamber ring-shaped soft gripper. (c) Four-chamber ring-shaped soft gripper. The inner wall of the ring-shaped soft gripper expands and deforms under input air pressure, contacting the target object and resulting in contact force. We took the threechamber ring-shaped soft gripper as an example to study the relationship between its contact force and input air pressure" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002964_9668973_09764737.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002964_9668973_09764737.pdf-Figure6-1.png", + "caption": "FIGURE 6. Strain Analysis.", + "texts": [ + "We conduct a deformation and strain analysis on the bogie of the first version and on the wheel frame of the second version of the rover keeping the pivot bar as a fixed support. The simulation was done based on the equation 1 where E denotes elasticity, \u03c3 denotes stress and \u03b5 denotes strain. E = \u03c3 \u03b5 (1) VOLUME 10, 2022 50733 It is observed from the deformation analysis (see Figure 5) that the maximum deformation under the critical load with a safety factor of 4 is 0.17 mm and 0.16 mm respectively. But significant change is found in strain analysis (see Figure 6) that maximum strain in the first version is found in the bent portion of the bogie, which leads to buckling. In the second version however, the maximum strain is observed at the bottom of the wheel frame, which is certainly not a critical position. This frame can tolerate the reaction force without developing any buckling and the rover can withstand impact using a four-wheel mechanism. Thus, a four-wheel chassis and drive subsystem was designed (see Figure 3(b)) with a semi-differential mechanism on the body which ensures maximum ground contact, preventing the rover from tipping at the pivot during extreme traversal" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004822_8948470_09167205.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004822_8948470_09167205.pdf-Figure1-1.png", + "caption": "FIGURE 1. (a) Mechanical design of robotic exoskeleton for supported shoulder-elbow motion. (b) Joint configurations assignment.", + "texts": [ + " OVERVIEW OF SYSTEM DESIGN The design targets to develop a compact, light-weight upper limb robotic exoskeleton that fits to the anatomical structure and agrees with the movement of the upper limb as close as possible. In general, the human upper limb mainly consists of seven degrees of freedom, but most executed rehabilitation exercises involve shoulder abduction/adduction, shoulder flexion/extension, shoulder internal/external rotation, and elbow flexion/extension. As such, a four-DOF upper-limb robotic exoskeleton design is presented in this paper. As shown in Fig. 1(a) for the shoulder joint mechanism, the first L type of link is actuated through the ring bearing joint 1 that is mounted to the shoulder plate. The ring bearing joint 2 that is fixed to the first L type of link drives the second L type of link, and the housing cap for the upper arm support is rotated by the ring bearing joint 3. The length of the housing cap is varied by connecting a sliding link to adapt the different lengths of human arms. The proposed design, as shown in Fig. 1(b), emulates the anatomical ball-andsocket shoulder joints of human beings, and kinematically equivalent to a serial chain with three perpendicular revolute joint axes intersecting at a single point [34]. Moreover, the shoulder abduction/adduction \u03b81, shoulder flexion/extension \u03b82, and shoulder internal/external rotation \u03b83 clearly agree VOLUME 8, 2020 149797 with the description of the ZYX Euler angles for a coordinate system assignment. In the elbow joint design, only allowed is the elbow flexion/extension \u03b84" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001904__wfces2021_01035.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001904__wfces2021_01035.pdf-Figure1-1.png", + "caption": "Fig. 1. Kinematic scheme of a mobile robot.", + "texts": [ + " However, the authors do not take into account the range of on-board sensors and sensors, which significantly limits the field of visibility of the robot; as a result, it is impossible to accurately identify the characteristics of the obstacle that the robot encounters during the movement. Based on the analysis of existing solutions, it can be concluded that the development of a method for planning the trajectory of a mobile robot, taking into account the limited capabilities of the on-board system, is an urgent and timely task. The paper considers a two-wheeled mobile robot with a differential drive, the kinematic scheme of which is shown in Figure 1. On Figure 1 x and y denote the position of the center of the robot axis in the global coordinate system, \u03b8 indicates the direction of movement of the mobile robot relative to the x-axis in the global coordinate system. Variable rw is robot\u2019s wheel radius, B \u2013 is the distance between the wheels. Finally, v and w are the linear and angular velocities, respectively, and wL and wR \u2013 are the rotational speeds of the left and right wheels, respectively. This model in the global coordinate system is one of the simplest and most minimalistic representations of a two-wheeled mobile robot" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure5.9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure5.9-1.png", + "caption": "Figure 5.9 Front View of Forklift\u2019s Center of Mass", + "texts": [ + "31 Rendering Model of the Forklift (P77) Figure 4.32 Collapsed View of Forklift (P78) Figure 4.33 Exploded View of Forklift (P79) Figure 5.1 Mass Property of Truck Body (P81) Figure 5.2 Mass Property of Counterweight (P82) Figure 5.3 Mass Property of Operator Cabin (P82) Figure 5.4 Mass Property of Supporting Mast (P83) Figure 5.5 Mass Property of Subassembly: Lifting Fork (P83) Figure 5.6 Mass Property of Subassembly: Scissor Lift (P84) Figure 5.7 Mass Property of Forklift Assembly (P84) Figure 5.8 Mass Safety Zone of Forklift (P85) Figure 5.9 Front View of Forklift\u2019s Center of Mass (P86) Figure 5.10 Top View of Forklift\u2019s Center of Mass (P86) Figure 5.11 Top View of Forklift with Stability Triangle Dimension (P87) Figure 5.12 Adjusted Stability Triangles (P88) Figure 5.13 Forklift with 3000kg load (P89) Figure 5.14 Mass Center Positon under 3000kg Load (P90) Figure 5.15 Forklift with 2000kg load (P91) Figure 5.16 Mass Center Positon under 2000kg Load (P92) Figure 6.1 Loading Part Analysis Demonstration (P95) Figure 6.2 Fork Meshing Model (P96) Figure 6", + " During the transportation, those roads would make the transportation bumpy, and it would cause sudden load on different part of the truck. Those sudden loads may cause truck failure. That is why the weight of the forklift matters. In our case, most warehouse floor could take a truck with such weight. Since we already have the data about the mass properties of all the components, we need to investigate if the forklift is safe under static conditions. This entails that forklift center of gravity needs to stay within the safety triangle, as shown in Figure 5.8; otherwise the forklift will tip over (see section 3.1.2). Figure 5.9 & Figure 5.10 shows clearly that when the forklift is under static condition, the center of gravity of the tuck remains in the safety triangle zone. The arrow in Figure 5.9 indicates that, when forks move up and down, the mass center also moves up and down, but it will still remain in the safety area. The arrow in Figure 5.10 indicates that, when forks move left and right, the mass center will also move to the left or right. Since this is a symmetric design, if the forklift can remain stable when forks are on one side (like shown in Figure 5.10, forklift is stable when the forks are on the right side), then it will also be safe when fork move to the other side. Section 5" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003068_RC_files_Vol2_04.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003068_RC_files_Vol2_04.pdf-Figure3-1.png", + "caption": "Figure 3. The complete mobile manipulator used during the competition, showing the Kinova robotic arm and the cargo bay attached to the Husky mobile base.", + "texts": [ + " On the other hand, the motors offer exceptional torque, and the rugged construction allows the robot to traverse difficult, uneven terrain. To minimize the time spent by transitioning between the pickup and the placement area, the robot was equipped with a custom-designed cargo bay, which can fit up to 7 bricks of red, green, and blue color. This way, the UGV can load and transport an entire layer of the wall section in one trip. The cargo bay is attached to the rear section of the robot as shown in Figure 3. For the brick manipulation, we employ a manipulator arm by Kinova Robotics. A Gen3 Kinova7 arm with 7 degrees of freedom (DOF) was chosen. The arm offers a working envelope, which is large enough to engulf all positions in the cargo bay, as well as all layers of bricks in the pickup zone. The added redundancy of the over-actuated manipulator also ensures exceptional dexterity of the arm. Thanks to these properties, the end effector can be oriented parallel to the ground at 6 https://clearpathrobotics" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001169_f_version_1618987687-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001169_f_version_1618987687-Figure11-1.png", + "caption": "Figure 11. Contact scenario during tool change.", + "texts": [ + " The overall goal was to deduce the applied wrench at the EE. The wrench applied at the EE and the base wrench were related by the transformation( IfB IMB ) \ufe38 \ufe37\ufe37 \ufe38 I hB = [ I 0 I r\u0303BE I ][ RI6 0 0 RI6 ] \ufe38 \ufe37\ufe37 \ufe38 TBE ( 6fE 6ME ) \ufe38 \ufe37\ufe37 \ufe38 6hE (22) where 6hE is the EE wrench represented in the body-fixed frame at the last (sixth) link, IhB is the wrench at the ground represented in the global inertial frame (I), and IrBE is the position vector from the base frame to the EE frame represented in the inertial frame (see Figure 11). The reduced base wrench comprising the measurements I fBz, I MBx, I MBy was thus determined by IhB,red = I fBz I MBx I MBy = STBE\ufe38 \ufe37\ufe37 \ufe38 TBE,red IhE. (23) This is an overdetermined linear system in the unknown EE wrench. The latter can be determined by solving the minimization problem min I hE 1 2 IhT EW IhE (24) s.t. IhB,red = TBE,red IhE where W is a weighting matrix. It has the unique solution IhE = W\u22121TT BE,red(TBE,redW\u22121TT BE,red) \u22121 IhB,red (25) = T# BE,red IhB,red. (26) For the tool changing task, the contact forces at the EE were most relevant, the weighting matrix could be chosen as W = diag [1, 1, 1, 50, 50, 50]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004762_f_version_1627444660-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004762_f_version_1627444660-Figure11-1.png", + "caption": "Figure 11. Wrist motion support part of the proposed exoskeleton robot.", + "texts": [ + " The custom-made semi-circular ring (spur) gear was fabricated out of stainless steel (stainless steel 304). The sleeves in the forearm cuff assembly were 3D printed using 1.75 mm PLA filament. The balls used in the forearm cuff assembly are standard 4 mm stainless steel balls. 2.6. Wrist Module The wrist module of the proposed exoskeleton functionality of u-Rob consists of two revolute joints to provide wrist radial\u2013ulnar deviation and flexion\u2013extension. Moreover, a force sensor was placed at the wrist handle to sense three Cartesian forces exerted by the user. As shown in Figure 11, the actuator assembly for joint-6 was mounted on the joint-6 base link; the base link was rigidly connected to the output of the forearm cuff. The output of actuator-6 was then fastened to wrist link-1. Note that the base link was designed so that it acts as a physical stopper for wrist link-1. The other end of wrist link-1 was rigidly fastened to wrist link-2, which houses the actuator assembly for joint-7. The output of actuator-7 was connected to wrist link-3 with a force sensor in between. The integration of the force sensor into the wrist module is shown in Figure 12", + " The custom-made semi-circular ring (spur) gear was fabricated out of stainless steel (stainless steel 304). The sleeves in the forearm cuff assembly were 3D printed using 1.75 mm PLA filament. The balls used in the forearm cuff assembly are standard 4 mm stainless steel balls. 2.6. Wrist Module The wrist module of the proposed exoskeleton functionality of u-Rob consists of two revolute joints to provide wrist radial\u2013ulnar deviation and flexion\u2013extension. Moreover, a force sensor was placed at the wrist handl to sense three Cartesian forces exerted by the user. As shown in Figure 11, the actuator assembly for joint-6 was mounted on the joint-6 base link; the base link was rigidly connected to the output of the forearm cuff. The output of actuator-6 was then fastened to wrist link-1. Note that the base link was designed so that it acts as a physical stopper for wrist link-1. The other end of wrist link-1 was rigidly fastened to wrist link-2, which houses the actuator assembly for joint-7. The output of actuat r-7 was connected to wri t link-3 with a force sensor in between. The integration of the force sensor into the wrist module is shown in Figure 12. Figure 11. Wrist motion support part of the proposed exoskeleton robot. Micromachines 2021, 12, 870 12 of 30 Micromachines 2021, 12, 870 13 of 32 Figure 12. Exploded view of the integration of the wrist force sensor into the proposed exoskeleton robot. During the fabrication of the wrist motion support part, aluminum was used for the fabrication of the joint-6 base link, wrist link-1, wrist link-2, wrist link-3, and plate-1. The computer-aided manufacturing (CAM) of these parts was designed in AutoCAD Fusion 360 and machined in CNC" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002378_0040949_09858332.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002378_0040949_09858332.pdf-Figure3-1.png", + "caption": "Fig. 3. Components of a FreeBOT module.", + "texts": [ + " An MSRR robot whose module can be freely connected, termed as FreeBOT, has been proposed by Liang et al. [27]. This section uses FreeBOTs to realize the kinematic motion of the two-DOF SRC joint and manipulator composed of SRC joints. The desired SRC joint motions are translated into those of the driving trolley inside the FreeBOT through path planning; then, the control method is proposed for the trolley, such that the trolley drives the SRC joint and end-effector of the manipulator to move as expected. A. FreeBOT Components As shown in Fig. 3, a FreeBOT is mainly composed of an iron sphere shell, a differential-wheel-driven trolley inside the shell, a permanent magnet at the trolley bottom, and other measurement and control units. When a FreeBOT moves over another one, the magnetic force between the permanent magnet of one FreeBOT and the iron shell of the other FreeBOT guarantees the two FreeBOTs not separated. A layer of ethylene-vinyl acetate (EVA) foam is applied to the outer surface of the iron sphere shell to increase friction forces and torques, such that the two FreeBOTs roll relatively without slipping at the contact point, and the rotation about the vertical axis of the tangent plane at the contact point is avoided", + " Then, we design that the trolley moves forward with the speed uif = s\u0307ri + ksi(s r i \u2212 si) (63) where ksi are positive constant gains. Given the forward dynamics of the trolley i that s\u0307i = uif , it is readily to prove that the forward speed in (63) guarantees the trolley going through the required arc distance sri . Therefore, the SRC joint i reaches the required position qr i . As a result, the end-effector reaches the desired pose I Ir d Bn and qd n,I in the task space. 3) Wheel Speeds: For the FreeBOT shown in Fig. 3, the forward and steering speeds of the driving trolley and the rotation speeds of its two differential wheels satisfy the following relationships (refer to Appendix C):\u23a7\u23a8\u23a9uif = ri,out ri,w\u221a 4 r2i,in\u2212l2i,w (\u03c9ir + \u03c9il) uis = ri,w li,w (\u03c9ir \u2212 \u03c9il) (64) where wir and wil represent the rotation speeds of the right and left wheels of the trolley i, respectively. Other parameters are defined in Fig. 5. Having obtained the trolley forward and steering speeds uif and uis in the trolley control method, the wheel speeds that generate uif and uis can be solved from (64)\u23a7\u23aa\u23a8\u23aa\u23a9 wir = \u221a 4 r2i,in\u2212l2i,w 2 ri,out ri,w uif + li,w 2 ri,w uis wil = \u221a 4 r2i,in\u2212l2i,w 2 ri,out ri,w uif \u2212 li,w 2 ri,w uis " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure29.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure29.5-1.png", + "caption": "FIGURE 29.5. Sketch of an idealized independent suspension.", + "texts": [ + "); others will be identical in modulus but with opposite sign (for instance, the product of inertia Jxy, some angles, etc.). In the latter case, reference will be made to the left suspension (subscript i = L), while the characteristics of the right suspension (subscript i = R) will have opposite sign. The simplest case, although only an ideal one, is a suspension in which the unsprung masses can only move along a straight line in the direction of the z axis of the sprung mass. The sprung mass is the main body, while the single suspension (wheel, hub and all parts attached to it) is the secondary body (Fig. 29.5). The suspension is constrained to the main body by a prismatic guide whose axis is parallel to the z axis. The reference point C is on the axis of the guide and the distance \u03b6 between the position C1 of C belonging to the sprung mass and C2 belonging to the unsprung mass is taken as a generalized coordinate. Obviously in the reference position with \u03b6 = 0, C1 coincides with C2. Moreover, assume that the directions of the axes of frame xuyuzu coincide with those of the axes of frame xyz. Consider as reference point for translational coordinates the same point H already used to compute the kinetic energy of the sprung mass" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004235_6514899_09469870.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004235_6514899_09469870.pdf-Figure1-1.png", + "caption": "FIGURE 1. Fingered end-effectors: (a) 2-finger type, (b) 3-finger type [3], [4].", + "texts": [ + " However, it does not consider the grasping stiffness of the robot hand, passively regulate it, or rely on the material\u2019s ductility that constitutes the robot hand. To grasp various unknown objects without damage, the grasping stiffness should be actively controlled. For the manipulator to perform the tasks, the end-effector should be installed at the distal part to enable interaction with the object. Most end-effectors currently in use in the industry are classified into two broad categories according to task: mechanical grippers and vacuum grippers. In particular, mechanical grippers such as those shown in figure 1 are used in 2-finger type and 3-finger type grippers [3], [4]. However, The associate editor coordinating the review of this manuscript and approving it for publication was Bidyadhar Subudhi . these grippers are limited to transporting simple forms of objects, which is a pick-and-place. A. ANTHROPOMORPHIC ROBOT HAND Recently, the anthropomorphic type of robot hands that can grasp and interact with various objects have been studied [5], [10]. The anthropomorphic type robot hand is a form that mimics a human hand, and it is a multi-finger type with 4-fingers or more (shown in figure 2)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004562_f_version_1639043485-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004562_f_version_1639043485-Figure13-1.png", + "caption": "Figure 13. Different grasping modes. (a) Parallel grasping. (b) Shape-adaptive grasping. (c) Adjusting the orientation of the distal phalanx of each finger.", + "texts": [ + "0 (\u03c6KBA is Constrained by the mechanical stopper)LEF= 72.0 LKI= 40.0 1 Referring to Figure 4b. Table 2. Specifications of the actuation system. FAULHABER Motor 1 1 Motor 2 2 Motor 3 2 Motor type 1724T012SR 1717T012SR 1717T012SR Rated torque 4.5 Nmm 2.1 Nmm 2.1 Nmm Controller type MCDC 3006 S MCDC 3006 S MCDC 3006 S 1 Denote the powerful motor fixed to the orange worm in Figure 12. 2 Denote the two less powerful motors fixed to the two green worms in Figure 12. Parallel grasping is demonstrated in Figure 13a. It can be found that the workspace of the gripper is very big and the maximum span of the gripper is around 260 mm. The payload for parallel grasping is around 2.5 kg. Figure 13b demonstrates the shape-adaptive grasping. Moreover, the orientation of the distal phalanx is decoupled from the open-close motion and can be actively adjusted as shown in Figure 13c. Thus, the orientation of the distal phalanx can be maintained at a desired angle during grasping, even when the distal phalanx makes a contact with the supported environment accidentally as shown in Figure 14. Hence, parallel grasping can be continued and we call this grasping mode \u2018environmental contact-based grasping\u2019. This grasping mode is very useful for grasping thin objects lying on flat surfaces. For many other grippers, instead, a combination of some new grasping strategy and special designs is required for picking up small objects lying on flat surfaces [39,47]", + "0L ( KBA\u03c6 is Constrained by the mechanical stopper) EF =72.0L KI =40.0L 1 Referring to Figure 4b. Table 2. Specifications of the actuation system. FAULHABER Motor 1 1 Motor 2 2 Motor 3 2 Motor type 1724T012SR 1717T012SR 1717T012SR Rat d torque 4.5 Nmm 2.1 Nmm 2.1 Nmm Controller type MCDC 3006 S MCDC 3006 S MCDC 3006 S 1 Denote the powerful motor fixed to the orange worm in Figure 12. 2 Denote the two less powerful motors fixed to the two green worms in Figure 12. Parallel grasping is demonstrated in Figure 13a. It can be found that the workspace of the gripper is very big and the maximum span of the gripper is around 260 mm. The payload for parallel grasping is around 2.5 kg. Figure 13b demonstrates the shape-adaptive gras ing. Moreover, t e orientation of the distal phalanx is decoupled from the openclose motion and can be actively adjusted as shown in Figure 13c. Thus, the orientation of the distal phalanx can be maintained at a desired angle during grasping, even when the distal phalanx makes a contact with the supported environment accidentally as shown in Figure 14. Henc , parallel grasping can b continued and w c l thi grasping mode \u2018environmental contact-based grasping\u2019. This grasping mode is very useful for grasping thin objects lying on flat surfaces. For many other grippers, instead, a combination of some new grasping strategy and special designs is required for picking up small objects lying on flat surfaces [39,47]. Figure 13. Different grasping modes. (a) Parallel gr sping. (b) Shape-adaptive grasping. (c) Adjusting the orientation of the distal phalanx of each finger. Machines 2021, 9, 347 15 of 26Machines 2021, 9, x FOR PEER REVIEW 15 of 26 Figure 14. Parallel grasping during making contact with the environment. (a) At the start point of the contact. (b) A reference state when the gripper moves upward with the robot arm but still in contact with the supported base. 5.2. Analysis of the Environmental Contact-Based Grasping The aforementioned contact-based grasping is very useful for picking up thin and small objects lying on flat surfaces" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003707_8600701_08758094.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003707_8600701_08758094.pdf-Figure1-1.png", + "caption": "FIGURE 1. Schematic illustration of the harmonic drive device.", + "texts": [ + " Finally, a brief conclusion is derived in Section 5. II. COLLISION IDENTIFICATION AND DYNAMIC MODEL FORMULATION A. COLLISION IDENTIFICATION Collision identification aims at estimating the coupled torques of each robotic joint, while the uncertain environmental collisions are acting along the robot structure [45]. In this part, a novel collision identification method is presented based on a nonlinear harmonic drive compliance model as well as the position and current measurements of each joint module. As illustrated in Figure 1, the adopted harmonic drive device includes a wave generator, a flexspline and a circular spline. The wave generator consists of an elliptical wave generator plug, which is assembly inserted into the ball-bearing, thus providing an elliptical shape for the bearing too. The flexspline, which is a thin cylindrical cup with external teeth, is designed with a slightly smaller pitch diameter than the circular spline with internal teeth. Since the flexspline has two less teeth than the circular spline, so that this may lead to a small phase deviation between the corresponding teeth in engagement" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003087_f_version_1583220629-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003087_f_version_1583220629-Figure2-1.png", + "caption": "Figure 2. The schematic diagram of a traditional direct drive hydraulic system.", + "texts": [ + " The mass matrix 1 1T act lq t lqM J M J\u2212 \u2212= is known as the joint space mass matrix. Then Equation (3) is rewritten as: 1 act aM f l\u2212 = , (4) where 1 actM \u2212 is the inverse matrix of the joint space mass matrix. As modal decomposition can be operated on the matrix above, then 1 actM \u2212 can be decomposed as [18]: 1 T actM = U U\u2212 \u03a3 , (5) where ( )1 2 6= diag \u03c3 \u03c3 \u03c3\u03a3 represents the characteristic value, and U is the modal decoupling matrix. 2.2. Introduction to the Direct Drive System Generally a traditional direct drive hydraulic system is shown in Figure 2, the control volume changes as the hydraulic pump rotates reversely, which results in low stiffness, so the dynamic characteristics of this system are poor. The dynamic characteristics of direct drive system will almost reach the same as that of servo valve control system only when the volume of both rod cavity and rod-less cavity are used as the control volume. for ease of control analysis and design, coulomb, coriolis/centripetal, and gravity terms are omitted. Substituting J\u22121 lq .. l \u2248 .. q into Equation (2), we have: fa = J\u22121 lq TMt J\u22121 lq ", + " The mass matrix Mact = J\u22121 lq TMt J\u22121 lq is known as the joint space mass matrix. Then Equation (3) is rewritten as: M\u22121 act fa = .. l, (4) where M\u22121 act is the inverse matrix of the joint space mass matrix. As modal decomposition can be operated on the matrix above, then M\u22121 act can be decomposed as [18]: M\u22121 act = U\u03a3UT, (5) where \u03a3 = diag ( \u03c31 \u03c32 \u00b7 \u00b7 \u00b7 \u03c36 ) represents the characteristic value, and U is the modal decoupling matrix. Generally a traditional di ect drive hydraulic system is shown in Figure 2, the control volume changes as the hydraulic pump rotates reversely, which results in low stiffness, so the dynamic characteristics of this system are poor. The dynamic characteristics of direct drive system will almost reach the same as that of servo valve control system only when the volume of both rod cavity and rod-less cavity are used as the control volume. Energies 2020, 13, 1125 4 of 13Energies\u00a02020,\u00a013,\u00a0x\u00a0FOR\u00a0PEER\u00a0REVIEW\u00a0 4\u00a0of\u00a014\u00a0 Figure\u00a02.\u00a0The\u00a0schematic\u00a0diagram\u00a0of\u00a0a\u00a0traditional\u00a0direct\u00a0drive\u00a0hydraulic\u00a0system.\u00a0 Plummer\u00a0proposed\u00a0a\u00a0direct\u00a0drive\u00a0hydraulic\u00a0system\u00a0 for\u00a0Stewart\u00a0manipulator[19].\u00a0A\u00a0modified\u00a0 system\u00a0which\u00a0is\u00a0adopted\u00a0in\u00a0this\u00a0paper\u00a0is\u00a0shown\u00a0in\u00a0Figure\u00a03.\u00a0Pressure\u00a0of\u00a0the\u00a0rod\u00a0cavity\u00a0and\u00a0the\u00a0rod\u2010 less\u00a0cavity\u00a0 is\u00a0designed\u00a0the\u00a0same\u00a0to\u00a0compensate\u00a0the\u00a0gravity\u00a0of\u00a0the\u00a0manipulator.\u00a0An\u00a0energy\u00a0storage\u00a0 accumulator\u00a0is\u00a0set\u00a0on\u00a0the\u00a0other\u00a0side\u00a0of\u00a0the\u00a0rod\u2010less\u00a0cavity\u00a0connected\u00a0to\u00a0the\u00a0motor,\u00a0and\u00a0the\u00a0pressure\u00a0of\u00a0 the\u00a0accumulator\u00a0is\u00a0set\u00a0to\u00a0be\u00a0the\u00a0same\u00a0as\u00a0that\u00a0in\u00a0the\u00a0rod\u2010less\u00a0cavity\u00a0and\u00a0rod\u00a0cavity" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003768_f_version_1658218931-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003768_f_version_1658218931-Figure1-1.png", + "caption": "Figure 1. Schematic of the artificial-muscle-driven snake robot kinematics, (a) geometry of the mechanism and (b) kinematics of the muscle length and the joint angle, and (c) the free body diagram of a module of the snake robot including the forces acting on the body of the snake robot", + "texts": [ + " The kinematics of robots is generally described through the mapping between three configuration spaces, actuator, joint, and Cartesian/operational spaces. Herein, the in- terrelationship between these three spaces for the snake robot was discussed to develop kinematic models, which will be used for the dynamic modeling and control of snake robots in the future. 2.1.1. Joint Position\u2013Muscle Vector Relationship The relationship between the muscle movement and joint position of a snake robot was developed and studied. As illustrated in Figure 1a, the muscles are attached to the links of the snake robot at two points on the right-side and two points on the left-side, where the muscle can freely rotate about those two points which keeps it straight during the rotation of the joint. To describe the motion of each muscle, the position vectors of the connecting points, pR 2,i\u22121 and pR 1,i, on the right side, are defined with respect to the body frame {i} at the joint {i\u2212 1}, and are obtained as follows i\u22121rp1,i = [ h1 + h2 cos(\u03c6i) + w sin(\u03c6i) h2 sin(\u03c6i)\u2212 w cos(\u03c6i) ] (1) i\u22121rp2,i\u22121 = [ h1 \u2212 h2 \u2212w ] (2) where h1, h2, w, and \u03c6i are the length of each link, distance from the joint to the attachment point, half width of each link, and the joint angle, as shown in Figure 1a,b, respectively. The vector di connecting these two points, corresponding to the muscle and called a muscle vector, can be obtained as di = i\u22121rp1,i \u2212 i\u22121rp2,i\u22121 = [ h2(1 + cos(\u03c6i)) + w sin(\u03c6i) h2 sin(\u03c6i) + w(1\u2212 cos(\u03c6i)) ] (3) Equation (3) can be written in the following form, di = (I + R\u0304(\u03c6i))g = D(\u03c6i)g (4) where I \u2208 R2\u00d72 is an identity matrix, R\u0304(\u03c6i) \u2208 O(2) is an improper rotation matrix, i.e., det(R\u0304) = \u22121 in terms of the joint angle, and g is a constant vector, which includes geometric information of the link given by R\u0304(\u03c6i) = [ cos(\u03c6i) sin(\u03c6i) sin(\u03c6i) \u2212 cos(\u03c6i) ] g = [ h2 w ] we define D : R2 \u2192 R2 as an operator that maps a geometric vector g to a muscle vector d", + " Substituting Equations (19), (26), and (29) into (30) yields, L(q, q\u0307) = 1 2 p\u0307TMpp\u0307 + 1 2 m\u03b81 \u03b8\u03072 1 + 1 2 \u02d9\u0303qTMd \u02d9\u0303q (31) whereMp \u2208 R2\u00d72 andMd \u2208 RN\u22122\u00d7N\u22122 are symmetric and positive-definite matrices given by, Mp = AT M\u0303A = [ m 0 0 m ] Md = \u039b\u2212T HT ( BT M\u0303B + IC ) H\u039b\u22121, the diagonal and off-diagonal terms ofMd are given as follows, Md(i, i) = m \u03bb2 i N \u2211 t=i+1 ( (N \u2212 t) + 1 4 ) g\u0302T g\u0302 + 2m \u03bb2 i N \u2211 j=t N\u22121 \u2211 k=j+1 (2(N \u2212 k) + 1)g\u0302T j kRg\u0302 + N \u2212 i \u03bb2 i Izz Md(i, j) = m \u03bb2 i N \u2211 t=i+j ( (N \u2212 t) + 1 4 ) g\u0302T g\u0302 + 2m \u03bb2 i N \u2211 s=t N\u22121 \u2211 k=s+1 (2(N \u2212 k) + 1)g\u0302T s kRg\u0302 + N \u2212 j \u03bb2 i Izz and m\u03b81 \u2208 R+, m\u03b81 = 1T ( BT M\u0303B + IC ) 1 = N \u2211 i=1 m ( (N \u2212 i) + 1 4 ) g\u0302T g\u0302 + N \u2211 j=1 N\u22121 \u2211 k=j+1 m(2(N \u2212 k) + 1)g\u0302T j kRg\u0302 + NIzz. Given Lagrangian L(q, q\u0307) of the robot, the equations of motion can be obtained by the Lagrange\u2013Euler equation [60], d dt ( \u2202L \u2202q\u0307 ) \u2212 \u2202L \u2202q = Q (32) where Q \u2208 RN+2 is a vector of the generalized forces acting on the snake-robot defined in Section 2.2.2. 2.2.2. Generalized Forces The free body diagram of two-adjacent links of the snake robot is shown in Figure 1c. The forces and moments acting on each body can be categorized into three groups of: (1) joint reaction forces, (2) friction forces, and (3) muscle actuation forces (on the left and right sides of each body). A vector of friction forces acting at the center of mass of each link can be written as follows, f f i = f f ,1 i e f 1 + f f ,2 i e f 2 (33) where the friction between the snake robot and the ground was modeled as the Coulomb friction with anisotropic properties, \u00b51 \u00b52. f f ,1 i = \u2212 1 \u2016\u03c5C i \u2016 \u00b51mig \u03c5C i \u00b7 e f 1 (34) f f ,2 i = \u2212 1 \u2016\u03c5C i \u2016 \u00b52mig \u03c5C i \u00b7 e f 2 (35) where mi and g are the mass of the ith link and the gravitational acceleration, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000379_f_version_1699952157-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000379_f_version_1699952157-Figure9-1.png", + "caption": "Figure 9. First approximation with orthogonal axis coplanar to the tendons. (a) Antagonistic cables screws representation. (b) Screw representation for the anchor points rotated 0.7854 radians.", + "texts": [ + " The model uses the screws in an antagonistic configuration to achieve tension forces at the cables. In Figure 8b, the view is normal to the proximal axis, and Figure 8a shows the normal view of the distal axis. We used this simplified model to compute the cable locations. Also, we can use the model for testing and calibrating the mechanism before use in humans. With the purpose of designing a reconfigurable physical model, we represent the rotational joints as axes located coincident in opposite edges on a tetrahedral structure, as shown in Figure 9. We chose two different configurations by rotating the anchor points by 0.7854 radians (half of 1.5708 radians) from their initial position on the base and the platform. The first coincides with the rotation axis as in Figure 9a, and the second configuration is similar to that observed in the ankle, and we show this configuration in Figure 9b. The first representation allows us to visually identify the intersection points between the tendons\u2019 lines of action. L$1 \u2229 L$12 = P1, L$2 \u2229 L$12 = P2 (27) L$3 \u2229 L$34 = P3, L$4 \u2229 L$34 = P4 (28) Such a condition results in null reciprocal twists because they are coplanar [91]. Therefore, the reciprocal products are: $1 \u25e6 $12 = 0, $2 \u25e6 $12 = 0, (29) $3 \u25e6 $34 = 0, $4 \u25e6 $34 = 0 (30) This configuration must be avoided because it leads to a singularity. The relations for all the tendons on the rotary joints are as follows: $12 \u25e6 ($1 + $2 + $3 + $4), $34 \u25e6 ($1 + $2 + $3 + $4) (31) In Figure 9a, we show the following: $1 \u25e6 $34 = \u2212$1 \u25e6 $34, $3 \u25e6 $12 = \u2212$4 \u25e6 $12 (32) Following that, the sum of all reciprocal products is zero, which means that the platform is in a static position. However, it is unstable because little variation in the anchor position suddenly changes the product\u2019s sign. In the second configuration, the twist pair $A and $C is antagonistic with regards to $B and $D about the proximal twist $x. Also, $C and $B are antagonistic with respect to $A and $D about the twist $t. We will use this in our design" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000217_f_version_1689676114-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000217_f_version_1689676114-Figure4-1.png", + "caption": "Figure 4. The motion state of the soft manipulator after contact with the environment.", + "texts": [ + " After judging the operational state of the soft manipulator, if there is no contact be- tween the soft manipulator and the obstacle, the static feedforward model is used to con- trol the motion of the soft manipulator. If there is contact between the soft manipulator and the obstacle, the control accuracy of the original static feedforward model is signifi- cantly reduced. Therefore, we improve the original static feedforward model. In its origi- nal state, we divide the contact-discrete manipulator segment into two continuous arcs with different curvatures, as shown in Figure 4. Because the soft manipulator has infinite degrees of freedom, any contact point can affect its final position. When the i-th segment of the soft manipulator generates c contact points, this i-th segment can be divided into c + 1 discrete segments. We simplify this model for ease of calculation. We assume that the i r . r ti l st t t ti r c ss f s ft i lator. j t the soft manipulator and the obstacle, the static feedforward model is used to c ntrol the motion of the soft manipulator. If there is contact betwe n the soft manipulator nd the obstacle, the control accur cy of the original static feedforward mo el is significa tly reduced. Therefore, we improve the original static feedforward model. In its original state, we divide the contact-discrete manipulator segment into two continuous arcs with different curvatures, as shown in Figure 4. Because the soft manipulator has infinite degrees of freedom, any contact point can affect its final position. When the i-th segment of the soft manipulator generates c contact points, this i-th segment can be divided into c + 1 discrete segments. We simplify this model for ease of calculation. We assume that the soft manipulator has only one contact point with the environment, and the contact position is Xj1 = [xj1, yj1, zj1, 1]T. The soft manipulator is divided into a contact-front segment and a contact-rear segment", + " When establishing the static feedforward model of the soft manipulator with contact constraints, the contact-front and contact-rear segments are analyzed. First, we calculate the equivalent contact point position along the central axis of the soft manipulator. After contact collision, the contact point on the soft manipulator and the environmental obstacle point are in the same position in space. We describe this condition as follows: ( )T0 1cos sin 0 1a s a s a jr r\u03d5 \u03d5 =H X (11) where rs is the cross-section radius of the soft manipulator, and \u03c6a represents the deflection angle of the a-th-segment soft manipulator. Figure 4. The motion state of the soft manipulator after contact with the environment. According to the above equation, when the contact point position is known, the homogeneous change matrix 0Ha of the soft manipulator contact-front segment can be obtained, and the equivalent contact point position is Xj2 = [xj2, yj2, zj2, 1]T. Because this contact point position is fixed, the equivalent contact point position is regarded as the expected position of the end of the contact-front segment. We define the desired position of the end point of the entire soft manipulator as X = [x, y, z, 1]T, such that 0 3a j =HX X (12) where Xj3 represents the expected position of the end point of the contact rear segment of the soft manipulator" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000225_lGoodyearBelting.pdf-Figure14-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000225_lGoodyearBelting.pdf-Figure14-1.png", + "caption": "Fig. 14", + "texts": [ + " The take-up carriage has a strong influence on the running of the belt at that point, and due to its movement as belt length changes, is subject to misalignment. A vertical take-up carriage, hanging in a festoon of belt, must be guided in its travel so that the pulley shaft remains horizontal. The belt cannot be depended upon to center itself on the pulley. Once it becomes off-center, the pulley will tip out of horizontal if not guided closely on its posts. 13 Installation, Maintenance & Troubleshooting Guide Installation A horizontal take-up carriage (Fig. 14) is subject to misalignment due to loose track gauge, fouled rails, or even jumping off the track. V-shaped rails will hold the gauge tight and, with the apex upward, are self-cleaning. Hold-down rails or hooks extending under the flange of the track structure will prevent jumping off the track. With the empty belt trained satisfactorily, good operation with load is usually ensured. Disturbances that appear with load are usually due to off-center loading or to accumulation of material from the load on snub pulleys and return idlers" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001537_f_version_1634787306-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001537_f_version_1634787306-Figure7-1.png", + "caption": "Figure 7. The leg model. (a) prototype of robot leg, (b) configuration parameters.", + "texts": [ + " It is expected that a small, large-reduction device combined with a counterpart motor will have an advantage over a large motor size [10]. However, this may reduce the transparency, and a trade-off between the abovementioned approaches should be made based on the specific application. Similarly, Cheetah 3\u2019s actuators couple a single-stage planetary gear reduction, which is slightly higher compared with Cheetah 2, to improve the load-carrying ability and low-speed efficiency of the robot. Finally, a symmetric leg with a high-density actuator was designed, as shown in Figure 7a. Figure 7b shows the schematics of leg model, for which it is assumed that all mass is lumped at the base and the two motors are coaxial. Here, Px, Pz are the position of the foot in the body coordinates, and are expressed by Equation (3). L1 and L2 are the upper and lower leg length, m is the mass of body, \u03b2 = q1\u2212q2 2 is virtual angle between the vertical and virtual leg L, \u03b1 = q1+q2 2 is the half angle between two upper leg. xk, zk is the position of center of mass (COM) in inertial coordinate. Px = sin \u03b1(L1 cos \u03b2 + (L2 2 \u2212 L2 1 + L2 1cos2\u03b2) 1/2) Pz = \u2212 cos \u03b1(L1 cos \u03b2 + (L2 2 \u2212 L2 1 + L2 1cos2\u03b2) 1/2) (3) The dynamics of leg model were formalized as a single point mass" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000032_f_version_1613481839-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000032_f_version_1613481839-Figure1-1.png", + "caption": "Figure 1. CAD model (virtual prototype) of the 6-DOF parallel manipulator with a circular guide.", + "texts": [ + " Moreover, the structure of these manipulators is organized in such a way that the possibility of collision between the adjacent carriages is not eliminated. In this regard, the proposed study aims at the designing and analysis of such a manipulator with a circular guide that provides placement of all drives fixed on the base, ensures elimination of the possibility of collision between the adjacent carriages while having a sufficiently large rotation of the end-effector around the vertical axis and providing six DOFs. Let us consider the structure and functional features of the proposed 6-DOF manipulator with a circular guide. Figure 1 presents its CAD (computer-aided design) model (virtual prototype). The model allows not only to fabricate its physical prototype but also to perform numerical calculations and experiments. The operation of the CAD model is presented in the movie in Supplementary Materials. The key elements in Figure 1 are: 1\u2014circular guide (fixed link); 2\u2014drive; 3\u2014crank; 4\u2014slide block; 5\u2014swinging arm; 6\u2014carriage; 7\u2014leg; 8\u2014platform (end-effector). Slide block 4 and swinging arm 5 form a prismatic joint, swinging arm 5 and carriage 6 form a single link (rigid connection), leg 7 is connected on both sides with carriage 6 and platform 8 by spherical joints. Figure 1 also demonstrates the main constructive assemblies of the manipulator: I\u2014the coupling of leg 7 and platform 8 through spherical joints; II\u2014the coupling of six swinging arms 5, which converge in the center of circular guide 1 and have a common rotational axis; III\u2014the coupling of links 1\u20136. In each of the six kinematic chains of the manipulator, the input motions pass from cranks 2 to slide blocks 4 and then to swinging arms 5, turning them at certain angles. Swinging arms 5 displace carriages 6 along circular guide 1", + " The studies above showed that in general (in the case of an arbitrarily chosen geometry of the manipulator), the system can have 40 different solutions, both real and complex, and Husty [30] provided an algorithm to form a univariate polynomial of 40th degree that allows finding all the solutions. Dietmaier also showed that all the solutions can be the real ones [31]. Any of the approaches above can be applied to solve the system of equations discussed in this study. The next section will discuss the examples of solving both position problems. Let us consider examples of solving the inverse and forward position problems for the manipulator with the following parameters, corresponding to the CAD model (Figure 1): radius of circular guide 1, R1 = 250 mm; length of crank 3, li = 40 mm, i = 1 . . . 6; length of leg 7, Li = 222 mm, i = 1 . . . 6; distance between points O and Bi, di = 160 mm, i = 1 . . . 6; angle between axis OX and length OBi, \u03b1i = 30\u25e6, 90\u25e6, 150\u25e6, 210\u25e6, 270\u25e6, 330\u25e6; coordinates of spherical joints 7\u20138 in local coordinate system PXPYPZP, rEi = [ R8cos\u03b2i R8sin\u03b2i 0 ]T, where R8 = 153 mm is the radius of platform 8; \u03b2i is the angular placement of joints 7\u20138, \u03b2i = 7.5\u25e6, 112.5\u25e6, 127.5\u25e6, 232.5\u25e6, 247" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003710_f_version_1675750732-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003710_f_version_1675750732-Figure3-1.png", + "caption": "Figure 3. Pattern diagram of the Omni wheel robot: The parameters of each wheel of an Omni wheel robot are shown when a wheel of radius r is placed at position (x,y) and direction \u03b8. \u03c9 and V are the rotational and ground speeds of the wheel, and l \u2032 are the distance to the center of rotation of the robot relative to the velocity vector of each wheel.", + "texts": [ + " Using this assumption, we can compute the moments that the velocity exerts on the robot\u2019s center of mass, velocity moments. If the moments are balanced, the robot would follow the straight-line motion correctly, otherwise, it would turn as it moves. Note that under our assumption, if the wheel\u2019s velocity vector is V. Then, the distance from the velocity vector to the origin is r, and the moment due to the wheel\u2019s velocity is proportional to Vr, which is different from the angular velocity \u03c9 = V r . From the schematic diagram of the Omni wheel robot shown in Figure 3, the moment generated by each wheel\u2019s ground speeds V is expressed as Vl \u2032 : where l \u2032 represents the distance to the robot turning center relative to the velocity vector. Moreover, L \u2032 is expressed by using the position (x, y) and angle \u03b8 of the Omni wheel as follows: l \u2032 = x sin \u03b8 \u2212 y cos \u03b8 = l sin(\u03b8 \u2212 \u03b2) (1) where l = \u221a x2 + y2 and \u03b2 = arctan( y x ) are the distance and direction of the Omni wheel to the robot turning center. Based on the equation relating wheel angular velocity to ground speed: V = r\u03c9, and previous study [18], the ground velocity of the wheels when advancing the robot in the x and y directions is determined by the inverse kinematics of the n-wheeled Omni wheel robot as follow: V1 V2 V3 " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001682_f_version_1566814295-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001682_f_version_1566814295-Figure6-1.png", + "caption": "Figure 6. (a) Epicyclical mechanism, left side is the initial state and right side is the final state; and (b) soft epicyclical mechanism, left side is the initial state of the section A-A and right side is the final state.", + "texts": [ + " The new driving mechanism is inspired by the epicyclical gear train, which is typically composed of two gears (one fixed and one mobile) whose centers are attached through a rigid link so-called carrier. The rotation of the carrier then creates a revolve of the mobile gear center around the fixed gear. As a result, due to the mechanical link between gears, a rotation is provided on the mobile gear. Furthermore, the rotation amount of the carrier can be different from the rotations of the mobile gear, which is controlled by the gears relation. Figure 6a exemplary shows an epicyclical gear train (whose gears are labeled with white circles to follow relative rotations) in which the carrier has rotate 90\u25e6 and the mobile gear 150\u25e6. Consequently, for our driving mechanism, we proposed a soft epicyclical mechanism in which: 1. The finger\u2019s phalanges replace the carrier; 2. The gears are replaced by two slotted pulleys; 3. The mechanical link is guaranteed by two crossed flexible wires, henceforth, tendons. Figure 6b shows the scheme of the driven mechanism, in which blue line represents the tendon that drives clockwise rotation; and the yellow line depicts the tendon used to produce counterclockwise rotation\u2014clockwise and counterclockwise rotations are assumed regarding the figure orientation. The i-th phalange of the finger begins in a vertical position, then, after a rotation, it reaches a horizontal position. The center of the mobile pulley orbits around the fixed pulley, and due to the effect of the tendons, the mobile pulley rotates" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000827_f_version_1624432525-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000827_f_version_1624432525-Figure1-1.png", + "caption": "Figure 1. Cont.", + "texts": [ + " This work is under a licensing process and the patent details are given in Section 7. This section presents in detail the design and prototype of the soft joint. The soft joint has an asymmetrical morphology that allows its end tip to be positioned in the three-dimensional environment, robustly supporting high loads during its performance. Its design provides greater flexibility and a wider range of movement than a rigid joint. It consists of a series of links with asymmetrical prism morphology and circular section pitch. A triangular morphology is represented in Figure 1. The small section and soft nature of the central axis of action, allow a greater bending capacity in all directions. The asymmetrical prismatic section provides the property of blocking and a natural protection, as well as the routing of the tendons for their action. The design performance is achieved by tendons that are routed through the asymmetric prismatic sections, as shown in Figure 2. It is possible to change the morphology of the prism and route the tendons through different points of these sections", + " In this configuration, the action is achieved by a single tendon, which is routed through the vertices that form the bending curve. Configuration 2 allows larger flexion of the joint, compared to Configuration 1, while also maintaining the natural protection of the joint. When the flexion is towards one of the edges of the triangle, the blocking curve has a smaller radius, as shown in Figure 3b. This is because the edges are closer to the central axis of rotation, as can be seen from the distance ratio d1 < d2 in Figure 1c. A larger bending occurs due to the fact that a larger bending angle is necessary before these edges contact each other and lock the joint structure. In this configuration, performance is achieved by the action of the two tendons that form the edge of the triangle where bending occurs. As mentioned above, there are several ways to operate soft robots. This paper focuses on operation by tendons of variable length using a winch coupled to a motor shaft. Tendon lengths must be translated into motor angular positions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004319_00176_FULLTEXT01.pdf-Figure3.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004319_00176_FULLTEXT01.pdf-Figure3.4-1.png", + "caption": "Figure 3.4: Typical FE lap joint model formulated using the contact method", + "texts": [], + "surrounding_texts": [ + "The next step in estimating the damping from bolted joints is to model the localized damping in structures. Here, one needs to capture the stiffness and damping parameters of an actual joint through these models. Typically, the models that represent damping in bolted joints can be categorized into three categories i.e. contact models, thin-layer elements, and connector elements." + ] + }, + { + "image_filename": "designv7_3_0000887_45583_FULLTEXT01.pdf-Figure1.2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000887_45583_FULLTEXT01.pdf-Figure1.2-1.png", + "caption": "Figure 1.2 The revolute joint and the prismatic joint are illustrated in picture (a) respectively (b). Picture (c) and (d) shows the cardan joint and a spherical joint. The arrows show the allowed movement of the rigid body while the other part is kept fixed.", + "texts": [ + " A controlling system and sensors are needed for controlling the actuators so that the end-effector is used as wanted. In this Master Thesis mainly the kinematic and dynamic properties of the robot will be studied. Therefore the construction of the manipulator structure is going to be in focus. There are basically two types of joints, prismatic joints and revolute joints. A prismatic joint permits a relative translation motion between two rigid bodies, whereas a revolute joint permits a relative rotational motion between two rigid bodies. This is illustrated in Figure 1.2 (a) and (b). Both joint types have one degree of freedom. By using two revolute joints, with the axes of rotation perpendicular to each other, one can easily form a universal joint. A universal joint, also called cardan joint, allows two links to bend in any direction and still transfer a rotation from one link to the other. Connecting a third revolute joint, perpendicular to the other two, would result in a spherical joint which has the same properties as the universal joint except that rotational motion cannot be transferred at all. Universal and Spherical joints have two respectively three degrees of freedom. The two joint types are shown in Figure 1.2 (c) and (d). 3 As mentioned before, a robot has a manipulator connected to a base and an end-effector. To be able to describe the movement of the tool, a fixed coordinate system must be introduced. This coordinate system is normally defined at the base. In this coordinate system, the tool is allowed to move with certain restrictions. The restrictions depend on robot joints, manipulator link construction and critical forces. The volume where the end-effector is allowed to move is called the workspace, see Figure 1" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004674_f_version_1631496038-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004674_f_version_1631496038-Figure5-1.png", + "caption": "Figure 5. Kinematics model of Wasp platform.", + "texts": [ + "sick.com/be/en/ detection-and-ranging-solutions/2d-lidar-sensors/tim5xx/tim581-2050101/p/p619344 accessed on 3 September 2021) and Intel RGB camera (Intel\u00ae RealSense\u2122 Depth Camera D435i, https://store.intelrealsense.com/buy-intel-realsense-depth-camera-d435i.html accessed on 3 September 2021) are connected to the computer for Wasp platform orientation, navigation and vision purposes, respectively. As a typical four-wheel Mecanum drive robot, the kinematics model of the Wasp platform is shown in Figure 5. The symbols are defined as below: \u2022 X, G, Y: The inertial frame. \u2022 xr, or, yr: The Wasp platform base frame. or is the center of robot base. \u2022 xwi, owi, ywi: The coordinate system of ith wheel. owi is the wheel center point. \u2022 \u03b1i: The angle between orowi and xr. \u2022 \u03b2i: The angel between xwi and ywi. \u2022 \u03b3i: The angle between vir and viw. \u2022 vir: The velocity of passive rollers in ith wheel. \u2022 vi\u03c9: The velocity of ith wheel correspond to wheel revolution. \u2022 lix: Half the distance between front wheels or rear wheels", + " Assuming that wheel slippage on the ground is negligible, and all the wheels are the same size with radius r, the inverse kinematics equation of the Wasp platform is shown in Equation (1), while the forward kinematics equation is shown in Equation (2), with T+ as the transpose matrix of the Jacobian matrix of the inverse kinematics equation. \u03c91 \u03c92 \u03c93 \u03c94 = \u22121 r cos(\u03b21\u2212\u03b31) sin \u03b31 sin(\u03b21\u2212\u03b31) sin \u03b31 l1 sin(\u03b21\u2212\u03b31\u2212\u03b11) sin \u03b31 cos(\u03b22\u2212\u03b32) sin \u03b32 sin(\u03b22\u2212\u03b32) sin \u03b32 l2 sin(\u03b22\u2212\u03b32\u2212\u03b12) sin \u03b32 cos(\u03b23\u2212\u03b33) sin \u03b33 sin(\u03b23\u2212\u03b33) sin \u03b33 l3 sin(\u03b23\u2212\u03b33\u2212\u03b13) sin \u03b33 cos(\u03b24\u2212\u03b34) sin \u03b34 sin(\u03b24\u2212\u03b34) sin \u03b34 l4 sin(\u03b24\u2212\u03b34\u2212\u03b14) sin \u03b34 vx vy \u03c9z (1) vx vy \u03c9z = T+ \u03c91 \u03c92 \u03c93 \u03c94 (2) Table 2 below presents the parameters of the Wasp platform (refer to Figure 5). By substituting and deriving (1) and (2), the inverse kinematics are given in (3) while the forward kinematics are given in (4). \u03c91 \u03c92 \u03c93 \u03c94 = \u22121 r 1 \u22121 \u2212(lx + ly) 1 1 (lx + ly) 1 1 \u2212(lx + ly) 1 \u22121 (lx + ly) vx vy \u03c9z (3) vx vy \u03c9z = r 4 1 1 1 1 \u22121 1 1 \u22121 \u2212 1 (lx+ly) 1 (lx+ly) \u2212 1 (lx+ly) 1 (lx+ly) . \u03c91 \u03c92 \u03c93 \u03c94 (4) Finally, (5) gives the angular velocity of each wheel, while (6)\u2013(8) provide the longitudinal velocity, transversal velocity and angular velocity of the Wasp platform, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-3-1.png", + "caption": "Figure 9-3. Typical independent Front Suspension System for Wheeled Vehicle", + "texts": [ + " SECTION III INDEPENDENT SUSPENSION SYSTEMS 9-6 GENERAL DISCUSSION The term \"independent suspension\" is applied to vehicle elastic support systems in which each wheel supports part of the total vehicle load with no intermediary connection between the wheels. Each wheel is free to oscillate independently of the other wheels. For wheeled vehicles, either the front or rear wheels, or both, may be independently suspended. They may be driven or free wheeling. 9-7 FREE WHEELING TYPE A typical independent front suspension for a light vehicle is shown in Figure 9-3. In this design, each wheel is held in alignment by a pair of rigid control arms (upper and lower wishbones). The vehicle weight is transferred from the frame to the rigidly attached cross member, to the coil spring and the lower wishbone, and finally, to the wheel. For the system shown, the shock absorbers are integrated with the upper control arms. Frequently, direct-acting hydraulic shock absorbers are used. With this type of unit, the one end of the damper is pivotally fastened to the lower control arm while the opposite end is pivotally mounted to the frame or body of the vehicle", + " The location of the roll axis for a given vehicle is an important factor with respect to the dynamic stability of the vehicle since the behavior of a vehicle as it travels along a curved path is influenced by the changes in tire loading and attitude resulting from roll. 9-7.2 WHEEL CONTROL The kinetic behavior of the wheels of a vehicle during vertical displacement relative to the body is influenced by the type of suspension system. For example, neglecting the effects of tire deflec- tion, the top of a wheel controlled by the double transverse link suspension arrangement (Figure 9-3) will move away from the center of curvature as a vehicle rolls during a turning maneuver. These changes in the camber angles of the wheels reduce the cornering ability of the tires. The vertical displacement of a wheel may generate gyroscopic or inertia torques, depending on' the particular arrangement of the control members that determine the path of the wheel. In addition, changes in camber and/or track during vertical movement may be inherent for particular suspension arrangements. For the typical front wheel independent suspension shown in Figure 9-3, it is usually desirable to minimize the amount of lateral movement (scrub) of the tire at the ground when the wheel moves upward from its normal loaded position. For a system composed of parallel, unequal length wishbones, this can be accomplished by choosing the proper ratio for the lengths of the upper and lower eontrol links. Figure 9-5 is a diagram of the kinematics of the system under consideration (Ref. 8). For a vertical displacement d of the wheel, points 1 and 2 move to 1' and 2', respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002632_8600701_08675965.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002632_8600701_08675965.pdf-Figure6-1.png", + "caption": "FIGURE 6. The trajectories of the robots in the formation.", + "texts": [ + "25 sin(\u03c0/10)) The moving duration is set as 30.0s and the sampling time is set as T = 0.1s. The directed communication topology of these robots is described as Fig. 5. So the adjacency matrix A, degree matrix D and connection weight matrix B are represented as: A = 0 0 1 0 0 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 ,D = 1 0 0 0 0 0 2 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 , B = diag(1, 0, 0, 0, 0) The velocities of RL are set as: vL(k) = 0.4 m/s, \u03c9L(k) = 0.2 rad/s, k = 0, . . . , 300. (41) VOLUME 7, 2019 43587 Fig. 6 shows the trajectories of the whole formation, the alight blue dotted line is the trajectory of the virtual leader robot RL while others are the trajectories of R1 \u2212 R5. Initially, the five followers formed an irregular pentagon and the formation\u2019s centroid (black line) was not on the desired path (RL\u2019s trajectory). Fig. 7 shows the linear velocities while Fig. 8 shows the angular velocities of follower and leader robots. Fig. 9-11 show the changing of the state errors 43588 VOLUME 7, 2019 between zi and zL and finally the errors converge to the origin" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003338_8600701_08695008.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003338_8600701_08695008.pdf-Figure1-1.png", + "caption": "FIGURE 1. Overhead crane system model.", + "texts": [ + " 3) The proposed method can achieve the minimum-time motion online planning for overhead cranes so that their transportation efficiency can be improved significantly in practical application. The remainder of the paper is organized as follows. Section 2 presents the crane model and the minimum-time motion planning problem. Section 3 gives the coupling analysis and the solution form of the planning problem. In section 4, the details of the online solving method are provided. Then the simulation and experimental results are illustrated and discussed in section 5. Finally, the conclusion is given in section 6. II. SYSTEM DESCRIPTION Figure 1 shows the overhead crane system model, including a rail, trolley, and payload. It is assumed that o is the origin of the trolley movement whose positive direction is to its right, and that the gravity axis and its right are the zero angle of payload swing and the positive direction of payload swing, respectively. x, \u03b8 , l, and g denote the trolley position, the payload swing angle, the rope\u2019s length and the gravity acceleration, respectively. Taking into account that the trolley horizontal movement generally occurs after the crane has hoisted the payload to a certain height, the change of the rope\u2019s length can be disregarded", + " In the uniform moving stage, the payload swing is only related to the initial state of its swing angle. But, it is found that the payload and the trolley can remain relatively static (the payload swing angle being constant) in the acceleration, deceleration, or uniform moving stage, if their state meets some certain conditions. These conditions can be obtained by analyzing the coupling between the trolley movement and payload swing. The forces balance state of payload and trolley during the acceleration or deceleration process is shown in Figure1. If the payload swing angle remains unchanged, according to Newton\u2019s second law, the trolley\u2019s acceleration should meet x\u0308 = \u2212gtan\u03b8 (\u03b8 < 0) and the payload swing rate \u03b8\u0307 = 0. If \u03b8 = \u2212\u03b8m, the trolley will move at the maximum positive acceleration x\u0308 = gtan\u03b8m, with meeting the constraint of the maximum swing angle. If the maximum acceleration am \u2265 gtan\u03b8m, the control condition is expressed as \u03b8 (t) = \u03b8m, \u03b8\u0307 (t) = 0, u(t) = \u00b1gtan\u03b8m. (6) If am < gtan\u03b8m, considering that the controller output should meet the constraint in (3), the maximum swing angle must be modified as follows: \u03b8m = arctan am g " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000706_(4)_2018_465-475.pdf-Figure16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000706_(4)_2018_465-475.pdf-Figure16-1.png", + "caption": "Figure 16. Interacting points on the shared face: (a) A pair of interacting points, (b) A single interacting point.", + "texts": [ + " Step1: Extend the split edges being coplanar with the remaining edge from the interacting points; Step2: Build the swept face with the remaining edge as silhouette and the extended edges as the leading curves; Step3: Split the swept faces with each other and retain the inside partitions; Fig. 15 shows an example of the adjacent-interacting region decomposition. In Fig. 15b, the split edges, e1 and e2, are geometrically interacting, and the face f 1 is built by performing the method PATCH. As the edges e3 and e4 are unprocessed, themethod SWEEP is executed to build the faces f 2 and f 3. The bridge-interacting region decomposition includes both repairing split face and partitioning shared face. The interacting points on the shared face may be alone or in pairs, as shown in Fig. 16. Based on whether the interacting points are in pair, the methods of PATCH and SWEEP are selectively performed. The associated flowchart is shown in Fig. 17. \u2022 Case1: The interacting points is a pair In this case, there are two pairs of co-defined edges. These edges are formed by the wedging of cutter, so and they are the split edge. The region to which the split edge belongs isBIR, another is IR. For example, in Fig. 18, e1 and e2, e3 and e4 are two pairs of split edges, and R2 isBIR, R1 is IR" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure2-20-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure2-20-1.png", + "caption": "Figure 2-20. Vehicle Crossing Trench", + "texts": [ + " Factors that affect the vehicle's ability to emerge from the water at difficult landing sites are: waterborne drawbar pull, water speed, aggressive grousers, ability to shift vehicle's center of gravity, and an adjustable ground clearance. 2-10.1.6 Man-Made Obstacles The most common man-made obstacles associated with terrain are trenches, ditches, and vertical walls. The difference between trenches and ditches, as the terms are used here, is the manner in which a vehicle crosses them. A trench is a horizontal void or cavity, relatively narrow with respect to the vehicle length, having vertical or near vertical walls (Figure 2-20). The vehfcle makes use of its length, longitudinal rigidity, location of its center of gravity, and its tractive characteristics to bridge the gap. A ditch, on the other hand, is a horizontal cavity that is relatively wide with respect to the vehicle length and usually has sloping sides (Figure 2-21). Since its width is such that it cannot be bridged by the vehicle, a crossing must be accomplished by entering the ditch at one side, traveling to the bottom, and climbing out the opposite side. Ditch-crossing capabilities depend upon such factors as: slope climbing ability, maximum angles of approach and departure, location of vehicle's center of gravity, suspension stiffness, and the presence or absence of projections on the vehicle that might interfere with the ditch profile" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003329_9347829_09170578.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003329_9347829_09170578.pdf-Figure5-1.png", + "caption": "Fig. 5. Sampling contact points. (a) The original object. (b) The sampled contact points. (c) The contact points distributed to one facet. (d) Removing bad contact points. Especially in (d), the white points are removed since they are too near to the boundary. The red points are the results of frNN screening.", + "texts": [ + " Like \u03b8pln and \u03b8fct, tbdry and trnn are tunable parameters of the grasp planner. Note that both the two refining processes are done locally in a facet. The overlapped samples on superimposed facets are not affected. Fig. 4 shows a graphical view of the two refining processes. In practice, trnn is determined by the size of finger pads. An end-effector contacts with objects at a region, instead of a single point. trnn specifies the radius of the contact region. It controls the density of planned grasps by removing nearby candidates. As a demonstration, Fig. 5 shows the process of sampling contact points using a plastic workpiece shown in Fig. 5(a). 3) Stability: The soft-finger contact (SFC) model proposed in [56] is used to estimate the stability of a grasp. The force and torque exerted by one SFC are expressed as follows: f Tt ft + \u03c42n e2n \u2264 \u03bc2f2 n. (1) Here, ft indicates the tangential force at the contact. \u03c42n indicates the torque at the contact. fn indicates the load applied in the direction of the contact normal. en is the eccentricity parameter that captures the relationship between maximum frictional force and moment. Under the Winkler elastic foundation model, en is en = max(\u03c4n) max(ft) = \u222b S r\u03bcKui(r)dS\u222b S \u03bcKui(r)dS (2) where K is the elastic modules of the foundation over the thickness of the soft finger pad, S is the contact surface between the finger pad and the object, r is the distance between a differential contact point and the center of the contact region, and ui(r) is the depth of the soft penetration" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001593_f_version_1680964364-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001593_f_version_1680964364-Figure13-1.png", + "caption": "Figure 13. Hovering and vertical motion.", + "texts": [ + " From a physical standpoint, in the center of mass of the drone acts the gravity force, while the four thrust forces, generated by the propulsion system, are applied to the edge of each arm. As a first approximation, one can consider the center of mass as being equidistant from the four electric motors. In the design phase, the authors tried to arrange the components symmetrically so that the propulsion forces, all equal in magnitude, and the gravity force do not generate moments in the hovering configuration. This peculiar behavior of the delivery drone is schematized in Figure 13. If the vector sum of the forces is positive along the z-axis, there is an acceleration that allows the quadcopter to lift [76]. In the opposite case, if the sum of the forces is negative along the z-axis, there is a decrease in altitude. Consequently, the hovering phase occurs when the sum of the forces is zero, as summarized in the equations reported below: 4 \u2211 i=1 FTi + Fg > 0, ascending motion 4 \u2211 i=1 FTi + Fg < 0, descending motion 4 \u2211 i=1 FTi + Fg = 0, hovering (60) A closed-loop PID controller attains the regulation of the vertical thrust" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002529_f_version_1685936996-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002529_f_version_1685936996-Figure11-1.png", + "caption": "Figure 11. Illustration of the criteria for the medium-height climbing Dobbins path.", + "texts": [ + " This means that the pitch angle can reach the termination point under the model restriction, and only a section of an arc can be added to the path. In order to increase the path length in this paper so that the climb height with pitch angle \u03b3 = \u00b1\u03b3\u0304 is exactly Xde \u2212 Xds, an additional section of path \u03b3 = sign(xde \u2212 xds)\u03b3\u0304 must be inserted. As indicated in Figure 10a, the arc is added after the starting helix if the final height is greater than the starting height. In Figure 10b, the arc is inserted before the end helix if the final height is lower than the starting height. The intermediate arc is parameterized as shown in Figure 11 to demonstrate how the Dubins path can be obtained for modest climb heights, where the expression for zi is given by Equation: zi = cs + R(\u03d5)(zs \u2212 cs) (18) On the basis of the discovered position (zi, \u03c8s + \u03d5), a typical Dubins aircraft path is then plotted to the endpoint. The path is a distance from: L(\u03d5) = \u03d5Rmin + Lcar(zi, \u03c8s + \u03d5, ze, \u03c8e) (19) The pitch angle \u03d5\u2217 is determined using the binary search algorithm, which produces: L(\u03d5\u2217) = tan\u03b3\u0304 = |zde \u2212 zds| (20) The following equation yields the corresponding Dubins aircraft path distance: Lair = L(\u03d5\u2217) cos \u03b3\u0304 . (21) The parameters required for modeling the planning of the Dubins aircraft path for the medium climb case are shown in Figure 11. The intermediate parameters introduced are ci, \u03c8i, \u03bbi, wi, qi, so the parameters of the Dubins aircraft path can be defined as: Dair = (R, \u03b3, cs, \u03c8s, \u03bbs, ws, qs, cs, \u03c8i, \u03bbi, wi, qi, wl , ql , ce, \u03c8e, \u03bbe, we, qe). (22) A Dubins airplane path with a medium altitude variation of 175 m and a Dubins automobile route distance of 185 m are depicted in Figure 12. 3. High Climbing Dobins Path: States within the model limitations cannot achieve height increments for starting or ending locations with significant height variations relative to the car path" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004047_8764082_08752419.pdf-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004047_8764082_08752419.pdf-Figure8-1.png", + "caption": "Fig. 8. The foot pads. Left: bottom views; Top left: the flat pad; Top right: the straight grouser pad; Bottom left: the V grouser pad; Bottom right: the SIB grouser pad. Right: side views; Top: straight grouser; Bottom: SIB grouser.", + "texts": [ + " The hopper is installed on a wood-board as a hard ground; the inclination of the hard ground is horizontal; a metal stopper is placed at the back of the foot pad to prevent slip, i.e. friction between the foot pad and the ground is assumed to be large enough. In the case of hopping with slip, the stopper is removed. The inclination of all terrains is leveled horizontally. The initial position and angle are measured by a goniometer, and the errors on the initial angle were less than \u00b10.5 [deg]. The foot pads are prepared for each injection angles (45, 60, and 75 degrees) and made of 3D printed PLA resin. An image of the foot pads is shown in Fig. 8. The hopping motion and distance are measured using motion capture cameras and the related software, Motive made by Optitrack. The mean error of this system is less than 0.5 [mm]. Furthermore, grousers are into the soil as an initial condition, and the bottom surface of the foot pad is on the soil surface. A. Validation and Evaluation of Hopping on Hard Ground This section describes the hopping experiments on hard ground with only the flat pad and hopping simulations. These simulations validate the hopping experiments on hard ground" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure3-1.png", + "caption": "Figure 3: Stress distribution in grey cast iron", + "texts": [], + "surrounding_texts": [ + "Fine meshing of tetrahedran type is done to get the accurate results of contact stress." + ] + }, + { + "image_filename": "designv7_3_0003396__encon2017_02031.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003396__encon2017_02031.pdf-Figure4-1.png", + "caption": "Figure 4. Test bed machine", + "texts": [ + " To start the assembly, these shaft components are placed at the both ends of the rubber tube. The mesh stripe is pulled to cover the rubber tube. Then the copper ring (21mm outer diameter, 19mm inner diameter) is placed at the both ends of the mesh stripe for finishing. Three jaws chuck used to tighten the copper ring to prevent air leaks during testing as shown in Figure 3. Finally, the copper ring is covered by tape to ensure no separation or pulls off occurs during bed testing. The assembled PAM is then tested by on test bed as shown in Figure 4. This test bed is able to generate force by muscle and test the contraction by muscle. The test bed consists of a compressor (IWATA SLP-22) that supplies the air to PAM, a regulator (SMC PSE540AR06) to regulate or maintain air, laser displacement meter (OMRON ZX-SLD300L) to measure the displacement on PAM during contraction and inflation, load cell (KYOWA LUR-A-2KNSA1) for measuring tension or compression loads, light reflector (OMRON E39-RS1) to measure the reflection of laser for displacement occurred, force magnitudes produced during PAM extension were amplified by a strain amplifier (KYOWA DPM-611B) and lastly (NATIONAL INSTRUMENT DAQ NI cDAQ9178) to record the acquired data from the test" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003985_9_isxn_9781668478943-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003985_9_isxn_9781668478943-Figure7-1.png", + "caption": "Figure 7. UGV hardware physical diagram", + "texts": [ + " With their Ackermann steering mechanism, they offer speed, torque, and maneuverability. ATVs have ample towing and load capacity, making them suitable for plantation applications. Their replaceable components, including tires, wheels, and suspension, simplify maintenance. The ATV underwent a comprehensive electrical and mechanical conversion, including integrating a 3-sub steering, throttle, and brake system utilizing a wire-based control system. The transformation process is illustrated in Figure 6 and Figure 7. An extended electrical and electronic system was implemented to accommodate the addition of sensors and actuators. This included the incorporation of actuators such as the Electric Power Steering (EPS), enabling steer-by-wire functionality, and two motor drivers to independently control the rear and forward motors. The specifications of the robot are outlined in Table 7. For a visual representation of the UGV\u2019s dimensions, please refer to Figure 8 and Figure 9. The vehicle drivetrain has two 60-volt 2000-watt BLDC motors, as depicted in Figure 10" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001274_f_version_1686809347-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001274_f_version_1686809347-Figure1-1.png", + "caption": "Figure 1. Posture errors of the coordinate for NMR.", + "texts": [ + " It is difficult to find a clear and explicit relationship between the control system parameters and the convergence time, which will lead to difficulty in tuning the convergence time of the system. The predefined time stability converts the complex expression of the convergence time estimation of the fixed time stability into an adjustable parameter Tc in the controller, and the system will achieve uniformly global stability within Tc, which makes the adjustment of the convergence time of the system easier and convenient. 2.2. Problem Formulation Figure 1 shows the model of an NMR. The NMR is driven by two drive wheels at its rear. d is the distance between the center of mass of the two drive wheels and the geometric center P. Choosing Pd as the reference tracking trajectory point, the attitude of an NMR can be defined in the ground coordinates as the following: p = [x, y, \u03b8]T ; x and y are the positions, and \u03b8 is the angle between the symmetry axis and the x axis [30]. For an NMR, if we consider the perturbation nonholonomic constraints of slipping and skidding, we can obtain: x\u0307 = (v\u2212 \u03b7v)cos\u03b8 \u2212 (\u00b5 + d\u03b8\u0307)sin\u03b8 y\u0307 = (v\u2212 \u03b7v)sin\u03b8 + (\u00b5 + d\u03b8\u0307)cos\u03b8 \u03b8\u0307 = w\u2212 \u03b7w , (6) where v is the longitude line velocity, \u00b5 is the lateral line velocity, \u03c9 is the angular speed, \u03b7w is the yaw rate perturbation due to the slipping of the wheels, and \u03b7v is the longitudinal slip velocity" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003007_d-Sutherland-PhD.pdf-Figure5-2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003007_d-Sutherland-PhD.pdf-Figure5-2-1.png", + "caption": "Figure 5-2 The Ballybot\u2019s system dynamics are very similar to that of the classic \"Inverted Pendulum\" problem. The Ballybot generates its own balancing force Fx by applying torque to the wheel motors.", + "texts": [], + "surrounding_texts": [ + "The Ballybot is an autonomous, single degree of freedom mobile robot, based on the model of an \u201cinverted pendulum\u201d. It consists of a rigid link, at the base of which are mounted a pair of wheels. The two wheels are mounted in parallel, sharing a common axis. As a result, the robot can rotate freely in the sagittal (x-y) plane, but is constrained from rotating in the frontal (y-z) plane. This design effectively makes the Ballybot a planar robot, simplifying the control system, sensor configuration and dynamic simulation. Lessons learned from experiments with planar robots can easily be extended to three dimensional systems. The Ballybot is an example of a \u201cpurely dynamic\u201d balancing robot, meaning that at no time will the robot be statically balanced. In order to maintain balance, the robot needs 125 to apply a variable horizontal force to its base. In traditional \u201cinverted pendulum\u201d architectures, an external balancing force is applied directly to a cart on which the pendulum is fastened. The Ballybot generates its own balancing horizontal force by inducing a ground reaction force through the application of motor torque to the robot\u2019s wheels. The robot has been designed to allow easy access to the controller\u2019s I/O ports, to make changing sensor configurations as simple as possible. Each wheel is independently driven, to allow the robot to be driven straight, as well as change direction while balancing. The resulting experimental robot is robust, simple to build and maintain, and inexpensive." + ] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.31-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.31-1.png", + "caption": "Figure 5.31: Concept 3:1 with new possible design", + "texts": [ + " One of the main issues that was brought up during the workshop was the issue of tightening and leak proofing flat metal surfaces in contact. The first concept uses the idea of having different dimensions for the frames mounting holes and corner fasteners, to squeeze the frame walls together. The second uses some variation of geometries to lock the walls together and supports on the corner fasteners to prevent the sides from bulging when the frame is compressed. Concept 3:1 can be seen below in figure 5.31. Using cones on the connectors and counter sinks in the floor of the wall pieces, the connector can be used to press the walls together when screwed in. The cone and counter sink does not have the same dimensions, because if they did the cone might bottom out before the walls are fully pressed against each other. The walls also houses fortifications to reduce bulging in the center of the walls when compression is applied. Concept 3:1, as seen below in figure 5.32, does not include the rear corner connectors to show the counter sinks that acts together with the cones on the connectors" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.49-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.49-1.png", + "caption": "Figure 5.49: Final idea of how 1:2 could look like", + "texts": [], + "surrounding_texts": [ + "The five concepts that were left from the last workshop and refinement were put under evaluation by the the workshops participants, and commented. The given comments can be viewed below in table 5.6. The participants was given the choice to choose the concepts that were most to their liking due to personal preference but mainly what they thought to be the most viable options using their experience and expertise in the field of sealing cables. The selection resulted with three concepts to focus on and further refine which are 1:2, 5:2 and 3:1.", + "The concepts presented during the third workshop are refined or altered based on the feedback and commentary that was given, and tweaked depending on uncertainties that arose. The refinement was concluded with three different versions instead of four due to concept 5:2 being concluded with one locking interface. These will be the final version to be presented and wont have any major future changes. All three concepts were 3D-printed for the last meeting with the problem owner for a last opinion and evaluation. 3:1 is printed in a smaller scale than the CAD-model due to restricted print volumes. 5:2\u2019s parts isn\u2019t fully engaged to prevent any damages before showcasing the concepts a final time.\nRefinement of concept 1:2, which can be viewed below in figures 5.49, 5.50 and 5.51. Concept 1:2 provides a possible minimum internal measurement equals zero, lesser amount of unique parts, lengthened side pieces for less points of failure and steering geometry for a guaranteed flat surface.", + "5.11. Refinement and finalization of concepts 81" + ] + }, + { + "image_filename": "designv7_3_0001071_9559726_09246671.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001071_9559726_09246671.pdf-Figure2-1.png", + "caption": "Fig. 2. Polishing machine and the robot are modeled as a bimanual system. The common coordinate frame is placed at the robot\u2019s base. p1 and p2 are the vectors, respectively, describing the position of the robot and the virtual mechanism. pr denotes the relative coordinates that define the task.", + "texts": [ + " To exploit this situation, we propose to model the machine tool as a serial kinematic chain, here called a virtual mechanism. The joints of the virtual mechanism define the point where the treated object held by a robot touches the machine tool. In order to represent the robot and the virtual mechanism in a unified system, we describe the resulting kinematic system as a bimanual robot [22] consisting of the real robot and the virtual mechanism. Only the relative coordinates of the bimanual setup are important for the accomplishment of the desired task. Fig. 2 shows an example where the robot and the polishing machine are modeled as a bimanual system. With this setup, the overall system becomes kinematically redundant in a standard definition of redundancy even though the robot itself is not. Thus, standard redundancy resolution schemes [23] can be applied to the resulting bimanual system, where the redundant DOFs can be used to optimize the robot joint space motion, e.g., by minimizing the joint velocities or by avoiding the joint limits, singularities, and collisions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-52-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-52-1.png", + "caption": "Figure 10-52. Rubber Band Track", + "texts": [ + " It is not used on combat-type tracked vehicles because of its strength limitations. 10-37.3.2 Rubber Band Track This term applies to the type of reinforced rubber track used in the American half-track vehicles of the 1930's and World War II. Lateral stiffness is obtained in this track by means of rigid cross members vulcanized into the rubber. The driving force is transmitted by the sprocket through these rigid cross members. In order to restrict the twisting of the track along its longitudinal axis, the track guide members are interlocked (see Figure 10-52). 10-37.3.3 Band-Block Track The band-block track has either rubber blocks or metal track bars bolted or riveted to the flexible, 10-68 AMCP 706-356 reinforced rubber bands. It is this type that has undergone the moat development and is now referred to simply'as the band track. Several of the more pertinent design details and functional advantages of this track are discussed in the paragraphs below. 10-373.4 Vehicle Speed The block and pin track induces substantial vibrations into the suspension system and vehicle hull when traveling at high speed" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000241_1145_3171221.3171283-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000241_1145_3171221.3171283-Figure4-1.png", + "caption": "Figure 4: Examples of the ranges in designs of the head structure and face animation. Iterations progressed from paper sketches to so ware renderings and small 3D printed prototypes and were informed by user input. Such feedback resulted in the ideation of a more robotic face (furthest right) which is di erent from the face shown in Figure 1.", + "texts": [], + "surrounding_texts": [ + "Brainstorming visual form factors of the head shape and internals took a lot of creativity, collaboration, and iteration as shown by a few examples in gure 4. We used many user-centered design methods to help us along the way including informal critiques, focus groups, and surveys. From the initial focus interviews, sketches were generated of di erent heads and visor shapes to help stimulate brainstorming. Each of these variants considered the general pros and cons of the respective design decisions like issues of visor shape, sensor visibility range, and suitability with the HUBO robot\u2019s design language. Going forward, we performed multiple evaluations as the delity of the designs increased from sketches in the hallway, emailed electronic renderings, and physical 3D printed prototype ballots. In the following we detail one design survey. 6.2.1 Method. Novices and experts (our expert HRI Mechanics) were presented with seven di erent design proposals and asked to rank their preferences based on their requirements (i.e., optical sensor expert focusing on visor re ections, novices just on visual features). Each design proposal highlighted one or two particular set of features of interest (discussed below). Design proposals were presented as renderings and 3D printed miniatures (see gure 5) with a description of the relative a ordances of each design. Participants were given a week to review all the models and submit their rankings and any additional comments or questions. 6.2.2 Prototype Variants. e series of prototype heads were generated focusing on both the form of the shell and the displayvisor. Each of which was a variant of the Reference design. Shell variations included rounded organic forms (i.e., Round&Flat), strict rectilinear shapes (i.e., Boxy), combinations of the two, and forms for extra large sensors (i.e., Spartan.) Visor variations were examined for sensing utility and potential for the display surface. Variants included at (for minimal distortion,) tapered-chin (to provide a more humanoid front pro le,) full and wide (for broader eld-ofviews.) 6.2.3 Results. Participants showed a consistent preference for the spartan (35%) and the tapered-chin (25%) visors. e comments support the notion that these were selected for sensor compatibility (the spartan can accommodate large form-factor sensors) and general aesthetics (participants noted some designs were too literal or \u201dtoo square\u201d.) ey seemed to expect the head to re ect the same rectangular design style of the HUBO and confessed most of them looked discordant when mounted on the HUBO. We combined these preferences into the current design iteration. e exterior shell incorporates both curved and linear forms for the front and back of the head, respectively. While mostly boxy, the Hubo uses a rounded wedge design for motor covers. ese have been adapted as SCIPRR\u2019s ear mounts for improved cohesiveness (see gure 1, le .) is analysis allowed us to determine the type of head shape that users preferred. Users seemed to mix both functional concerns (the spartan design had the space for one of the biggest sensors available) and aesthetics (curved and linear to match the Hubo aesthetic)." + ] + }, + { + "image_filename": "designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure4-1.png", + "caption": "Figure 4: Safety Factor in grey cast iron", + "texts": [], + "surrounding_texts": [ + "Fine meshing of tetrahedran type is done to get the accurate results of contact stress." + ] + }, + { + "image_filename": "designv7_3_0003493_79932_FULLTEXT01.pdf-Figure3.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003493_79932_FULLTEXT01.pdf-Figure3.4-1.png", + "caption": "Figure 3.4: Cross section of a dovetail", + "texts": [ + "4) Where: \u03d5ei = z \u00b7 \u03c9e 360 (3.5) \u03c9e = arcsin ( 2 \u00b7 ae1 Dcap ) + arcsin ( 2 \u00b7 ae2 Dcap ) = 2 \u00b7 arcsin ( ae Dcap ) (3.6) 2Figure courtesy of Sandvik Coromant AB [4] 17 When Equation 3.1 to 3.6 are combined the following expression can be used to determine Fzm directly from the input. Fzm = kc1 \u00b7 z \u00b7 ap \u00b7 arcsin ( ae Dcap ) 180 \u00b7 sin (\u03bar) \u00b7 180 \u00b7 sin (\u03bar) \u00b7 ae \u00b7 fz \u03c0 \u00b7Dcap \u00b7 arcsin ( ae Dcap ) \u2212mc (3.7) In this specific case the cutting width, ae, depends on the cutting depth, ap, as described in Figure 3.4 and Equation 3.8 to 3.10. X \u00b7 sin (65\u25e6) = Ae1 X \u00b7 cos (65\u25e6) = ap } \u21d2 Ae1 = ap \u00b7 tan (65\u25e6) (3.8) Y \u00b7 sin (25\u25e6) = Ae2 Y \u00b7 cos (25\u25e6) = ap } \u21d2 Ae2 = ap \u00b7 tan (25\u25e6) (3.9) ae = Ae1 +Ae2 = ap (tan (65 \u25e6) + tan (25\u25e6)) (3.10) 18 If Equation 3.10 is inserted in Equation 3.7, it becomes: Fzm = kc1\u00b7 z \u00b7 ap \u00b7 arcsin ( ap(tan(65\u25e6)+tan(25\u25e6)) Dcap ) 180 \u00b7 sin (\u03bar) \u00b7 180 \u00b7 sin (\u03bar) \u00b7 ae \u00b7 fz \u03c0 \u00b7Dcap \u00b7 arcsin ( ap (tan (65 \u25e6) + tan (25\u25e6)) Dcap ) \u2212mc (3.11) The power needed to remove material is calculated by multiplying a removal rate (cutting width, cutting depth and feed, vf ) with the specific cutting force: Pc = ap \u00b7 ae \u00b7 vf \u00b7 kc 60 \u00b7 106 (3" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001337_f_version_1621516578-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001337_f_version_1621516578-Figure1-1.png", + "caption": "Figure 1. Force sensor integration into hexapod structures and kinematics: approach and sensor placement; 1a: Rigid not moving hexapod structure (e.g., clamping table), 1b: Rigid moving hexapod structure (e.g., end-effector platform), 2x: Hexapod kinematics with sensors in the struts at various positions [1\u20133].", + "texts": [ + " The results are applicable for all Stewart Platform based force sensors presented in the literature overview that can now also be applied at the moving end-effector of a machine tool or robot. Finally, FT sensors can also benefit from a measurement model and a parameter identification procedure when used during movement. A hexapod-based end-effector is one of multiple options to integrate force sensors into hexapod structures and kinematics, which can be classified into not moving and moving rigid sensor frameworks as well as kinematic-integrated sensors. Figure 1 shows 5 approaches for sensor integration and 2 standard solutions (R: 6 DoF FT sensor, C: drive measurement) as reference. To achieve an accurate measurement, machine and process induced influences need to be compensated from force sensor signals for all setups. Depending on the exact sensor placement, different influences are included into a measurement model, that accordingly requires parameters and online-calculated machine states. The larger the distance between TCP and sensors within the machine structure, the more parameters need to be taken into account, which, as a result, lead to higher modelling and parametrisation efforts, and higher measurement uncertainties" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001650_32489_FULLTEXT01.pdf-Figure24-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001650_32489_FULLTEXT01.pdf-Figure24-1.png", + "caption": "Figure 24. Corrected Cycloid Drive (Rao Zhengang, 1994)", + "texts": [ + "2) Where, is the number of pins in the housing, is the input torque, - coefficient of width shortening of the epicycloid wheel, - number of lobes and - pitch radius of pins. The force is on the Y axis: \u2211 [ ( ) ] ( ) [ ( )] (Eq.2.2.3) Force F is acting between the eccentric bearing and the cycloid disc (driving force) and its value can be determined by: ( ( ) (Eq.2.2.4) ( ( ) (Eq.2.2.5) 33 Biser Borislavov, Ivaylo Borisov, Vilislav Panchev And the total force can be determined: \u221a( (Eq.2.2.6) Force is acting between the output shaft rollers and disc. Its value can be determined with equation (2.2.7). -Diameter of output pins . In Figure 24 is shown where these diameters are situated. Where: is the output pins\u2019 diameter, is the roller diameter and with is designated the disc\u2019s hole diameter. To calculate the diameter, first the force - (acting on the rollers shown on figure below) should be taken into consideration. The force is calculated by the following equation: Tg Zw (Eq2.2.7) Where with is designated the torque per cycloid disc. The number of holes in the gear for the output pins is presented with ; and is referred to the radius on which the pins are located" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure7-4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure7-4-1.png", + "caption": "Figure 7-4. Mechanical Liquid Limit Device", + "texts": [ + " Air gaps under the instrument of one eighth inch can cause errors of 10 percent or more. 7-2.5 ATTERBERG LIMITS (Refs. 3, 4) 7-2.5.1 Liquid Limit The liquid limit LL is the water content corresponding to the arbitrarily determined boundary between the liquid and plastic states of consistency of a soil. It is considered to be the moisture content at which two halves of a soil pat separated by a groove of standard dimensions will close at the bottom of the groove for a distance of one-half inch under the impact of 25 blows in a standard liquid limit apparatus (Figure 7-4). Trials are performed with samples at several different moisture contents and a plot is made of moisture content (arithmetic scale) versus the number of blows (log scale) required to close the groove over the prescribed length. The liquid limit can then be read from the linear plot obtained and a trial at exactly 25 blows is not required. 7-2.5.2 Plastic Limit The plastic limit PL is the water content corresponding to an arbitrarily defined limit between the 7-9 AMCP 706-356 plastic and the semisolid states of consistency of soil" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000887_45583_FULLTEXT01.pdf-Figure5.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000887_45583_FULLTEXT01.pdf-Figure5.5-1.png", + "caption": "Figure 5.5 The smallest footprint (a) that can be found by skewing the robot is compared with the standard footprint (b). The arms are placed in a way that still leaves some place for attaching motors within the footprint. This configuration has a footprint that is approximately 58% (circular) and 62% (rectangular) of the original footprint.", + "texts": [ + " The second observation is that increasing the lower skew makes the footprint shrink faster for increasing upper skews e1. In this way the footprint can be decreased by increasing the plate size. There is no need for evaluating lower-skews larger than e2=0.2m since it would result in a plate that is too large. The footprint is mainly dependent on the length of the upper arms and their position. The upper arms must not collide when placing them. Therefore the smallest achievable footprint would be placing the arms as in Figure 5.5 (a). This placement of the arms is interesting because there is no way to get the footprint this small without introducing an upper skew to the robot. This configuration will be investigated closer in Section 5.6. The minimum footprint that can be achieved without changing the size of the upper arm has approximately a diameter of 0.64m or a width of 0.54m which is 58% (circular) and 62% (rectangular) of the original footprint. To get this configuration the parameters are changed to e1=0.15m and R=0" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure46-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure46-1.png", + "caption": "Figure 46. Prototype of present MFL magnetic crawler large test platform used to collect data from the laboratory test bed above water. This version is not waterproofed and is not capable of being submerged (dimensions: 18 in. wide, 21 in. long, and 7 in. tall).", + "texts": [ + " Software was developed and successfully tested which employs a PID as the feedback mechanism for vertical ERDC/ITL TR-19-2 51 alignment of the mobile platform as it navigates towards the upper and lower end points of the vertical path. As illustrated in Figure 54 above, once the mobile platform reaches the upper or lower end position of the move (black circle) a horizontal move is made to the next start position (green circle). This horizontal move eliminates the need for complex skid-like turns that typically lead to platform alignment errors. Furthermore, horizontal moves to start positions can reduce overall inspection time. In Figure 46 (located in Section 4.1.3), the prototype platform is outfitted with non-magnetic Mecanum wheels to test platform horizontal moves. Considering that the pull force of the magnetic flux sensor is approximately 113 lb and the total payload of the platform (in air) is 50 lb, horizontal moves on vertical surfaces were tested. Unfortunately, however, the non-magnetic Mecanum wheels were found to have insufficient friction (causing slippage) to maintain proper orientation during the horizontal move. A new wheel design is presently under development that can potentially alleviate the slippage issue during horizontal moves; however, the new wheel (and supporting infrastructure) has not yet been manufactured for testing" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure17-1.png", + "caption": "Figure 17. Three-axis XYZ Table for magnetic flux sensor test.", + "texts": [ + "0 mt, the MFSD was ERDC/ITL TR-19-2 19 designed to satisfy this condition. The prototype design consists of two nickel-coated N42 grade neodymium magnets of dimension 2 in. \u00d7 0.375 in. \u00d7 0.375 in. (Figure 16). The combined pull force of the magnets was 11.3 pounds (lb). The dimensions of the steel flux bridge was 2 in. \u00d7 5.5 in. \u2022 3-Axis (XYZ) Table \u2013 The XYZ Table was for delivering the MFSD to targeted areas on a test substrate with sub-millimeter precision. A water tank could be placed below the XYZ Table (Figure 17) to provide a wet test area. The extent of travel was approximately 0.5 meter (m) in the x- and y-direction, and 0.15 m in the z-direction. ERDC/ITL TR-19-2 20 \u2022 Test Substrate \u2013 The test substrate provided a standard consisting of 12 defects of various shape and depth. The standard was made of rolled steel with thickness of 0.25 in. and dimensions of 2 feet (ft) \u00d7 2 ft. The standard was divided into four zones (Figure 18): o Square cut zone \u2013 four 1 in. \u00d7 1 in. squares of depth varying from 0.0625 in" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001279_9634176_09434946.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001279_9634176_09434946.pdf-Figure2-1.png", + "caption": "Fig. 2. Regularized contact conditions: (a) a module in contact with the ground, (b) contact-separation condition for fz component, and (c) tilting (stable/unstable) condition for my component. The dashed lines indicate the respective \u201cexact\u201d (nonregularized) relationships for the case of a rigid module in contact with rigid ground.", + "texts": [ + " We say that a module is in contact if the axial force in the beam representing the contact is compressive. Otherwise, the module is in separation. When in contact, the module can only tilt if the bending torque in the beam exceeds a limit torque, which is proportional to the compressive force (see the explanation below). Without loss of generality, let us consider a module supported from below. The module is loaded with the forces and torques F = [fx, fy, fz,mx,my,mz] T, which correspond to the kinematic variables u = [ux, uy, uz, \u03c4x, \u03c4y, \u03c4z] T. The contact condition [see Fig. 2(b)] takes the form of the Signorini problem: fz \u2264 0 & uz \u2265 0 & fzuz = 0. (6) Additionally, we require that when the contact is active (fz < 0), there is no tangential slip (ux = 0 & uy = 0) or twisting (\u03c4z = 0), and the module can only tilt if at least one of the bending torques exceeds a limit torque. The tilting conditions [see Fig. 2(c)] can be conveniently written in the following form: \u03a6x \u2264 0 & \u03c4x \u00b7 sign(m\u0302x) \u2265 0 & \u03a6x \u00b7 \u03c4x = 0 where m\u0302x = mx \u2212 fy \u00b7 L/2 , \u03a6x = |m\u0302x|+ fz \u00b7 L/2 (7) \u03a6y \u2264 0 & \u03c4y \u00b7 sign(m\u0302y) \u2265 0 & \u03a6y \u00b7 \u03c4y = 0 where m\u0302y = my + fx \u00b7 L/2 , \u03a6y = |m\u0302y|+ fz \u00b7 L/2 (8) where L is the module\u2019s size. The tilting (bending) condition expresses the fact that the torques |m\u0302x| or |m\u0302y| cannot exceed the torque \u2212fz \u00b7 L/2 produced by the compressive force \u2212fz about any of the facet\u2019s edges; see also Fig. 2(a). A supported module is modeled as a beam with the same elastic constants as two connected modules. This gives the force\u2013displacement relationship for the case of stable contact (when the module adheres to the support with an entire facet). This relationship is then used by a special predictor\u2013corrector scheme, described below, which provides regularization to the contact conditions given by (6)\u2013(8). In the regularized contact scheme for module p, a trial state is computed first, assuming a linear-beam-type connection with each support q (here, the contact direction is z): Ftr pq = [f tr x , f tr y , f tr z ,mtr x ,m tr y ,m tr z ] T = K11 pqu\u0304p (9) where the term K12 pqu\u0304q is absent because the support is assumed to be immobile u\u0304q = 0" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004640_9312710_09369351.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004640_9312710_09369351.pdf-Figure2-1.png", + "caption": "FIGURE 2. ResQbot \u2014 a previously developed robot (in the middle) for autonomous casualty extraction \u2014 and several fundamental aspects used behind the design of good casualty extraction robots.", + "texts": [ + " In this phase, the mobile robot is required to safely navigate its way from the disaster scene towards a safe place where the casualty can receive further medical assistance. B. AUTONOMOUS CASUALTY EXTRACTION ROBOT Our long term research goal is to develop an autonomous mobile robot that can help in emergency situations, with the ability to autonomously rescue an injured person lying on the ground \u2014 i.e. casualty extraction. The fundamental characteristics that an autonomous rescue robot performing casualty extraction should possess are (summarised in Fig. 2): \u2022 Safe: It is critical that the safety of the casualty is ensured at all times. In particular, approaching, loading and transporting the casualty should be performed in a way that minimises the risk of additional injury to the casualty. VOLUME 9, 2021 39657 \u2022 Hazard-aware: The casualty extraction process can be hazardous as the environment could be dynamically changing during the process. To adapt to this, the rescue robot should be able to update its extraction strategy in real-time according to current hazards and obstacles", + " In these studies, a stretcher-type construction or litter is implemented to achieve a more compact and simpler mechanism, compared to the semi-humanoid-type design. In the stretcher-type design, the casualty extraction procedure is achieved by using a conveyor belt mechanism that loads a casualty from the ground onto the mobile platform without any direct lifting process. The conveyor belt module properly supports the casualty\u2019s body during the process so it can additionally serve as a stretcher bed for transport. Introduced in our previous works, ResQbot (see Fig. 2) is a stretcher-type mobile rescue robot designed to load the casualty using a loco-manipulation approach, i.e. using the robot\u2019s locomotion system \u2014 wheeled locomotion \u2014 to perform a manipulation task [11]. It was found that teleoperating the loco-manipulation process allows the robot to load the casualty while ensuring key safety thresholds are adhered to [12]; avoiding possible causes of head or neck injury [23], [24]. Compared to the semi-humanoid-type design, the stretcher-type mechanism is significantly simpler" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004179_frame_structures.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004179_frame_structures.pdf-Figure2-1.png", + "caption": "Figure 2A Partial-width notches", + "texts": [ + "3 Coped Tension Face Notches A gradual change in cross section compared with a square notch decreases the actual shear stress parallel to the grain nearly to that computed for an unnotched bending member with the same net depth dn. Such a gradual change shall be achieved by providing smooth transitions between surfaces with no overcuts at reentrant corners. TFEC 1-2010 Standard Page 11 June 2010 A partial-width notch is a notch on the face of a bending member that does not extend across the full width of the face (see Figure 2A). 2.3.4.1 The width w1 of a partial-width notch on the tension or compression face of a bending member shall not exceed one-third the breadth b of the member. The flexural and shear capacities of the member shall be determined by the principles of engineering mechanics using the net cross section of the member at the notch. 2.3.4.2 A partial-width notch on the lateral face of a bending member shall have width w2 no greater than d/4. The flexural and shear capacities of the member shall be determined by the principles of engineering mechanics using the net cross section of the member at the notch", + "3 A partial-width notch extending from the compression face down the lateral face of a bending member shall have a width w3 not exceeding b/4. The flexural and shear TFEC 1-2010 Standard Page 12 June 2010 capacities of the member shall be determined by the principles of engineering mechanics using an effective rectangular cross section consisting of the depth of the member and the net breadth bn of the member at the notch. If the clear distance between such notches on opposing faces of the member exceeds 6b, the notches shall be regarded as occurring at different cross sections (see Figure 2B-a). If the clear distance between notches on opposing faces of the member is less than 6b, the notches shall be regarded as occurring at the same cross section location (see Figure 2B-b) TFEC 1-2010 Standard Page 13 June 2010 3.0 Connections Chapter 3 applies to the engineering design of connections using wood-on-wood bearing and wood fasteners, including pegs and wedges, for load transfer. The provisions of the ANSI/AF&PA NDS\u00a9 shall apply for the design of connections using metallic fasteners and metal connector plates. 3.1.1.1 \u201cEdge distance\u201d is the distance lv from the edge of a member or the inside face of a housing to the center of the nearest fastener, measured perpendicular to grain" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004579_00466_FULLTEXT01.pdf-Figure3.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004579_00466_FULLTEXT01.pdf-Figure3.5-1.png", + "caption": "Figure 3.5. Schematic picture of the arm mechanism drawn in Adobe Illustrator", + "texts": [ + " The black pixels are drawn with 100 percent dots in the pixel area, the gray with 50 percent and the white with 0 percent. In this way the robot will generate a gray scale image with three different shades of brightness of the pixels. The image processing of an example picture step by step is shown in Figure 3.4. 13 CHAPTER 3. DEMONSTRATOR An analysis of the geometry of the four bar mechanism was made to determine the relationship between the four axis geometry and the position of the pen. A schematic picture of the mechanism in a two dimensional view is presented below in Figure 3.5. Parameters for the arm parts of the mechanism are presented in Table 3.4.2. 14 The unknown parameters to be determined are the angles, their dependency of each other and a given pen position. The analysis is made by determining closed geometrical loops of the arm geometry, as explained in section 2.3. This gives the equation system 0 = L1 cos\u03b2 \u2212 L2 cos \u03b3 \u2212 L3 cos\u03c3 + L4 cos\u03b1 (3.1) 0 = L1 sin \u03b2 + L2 sin \u03b3 \u2212 L3 sin \u03c3 \u2212 L4 sin\u03b1 (3.2) 0 = \u2212L4 cos\u03b1\u2212 L5 cos\u03c3 + \u03c6 (3.3) 0 = L4 sin\u03b1\u2212 L5 sin \u03c3 + \u03c6 (3.4) The system is solved with the numerical method Newton Raphson to require full information about the angles dependency on each other and on the given position" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003594_cle_download_688_513-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003594_cle_download_688_513-Figure4-1.png", + "caption": "Figure 4. Representation of the acronym N, S, A of the wrist [12].", + "texts": [ + " Since these coordinate systems fixed to the link are assigned, transformations between adjacent coordinate systems can be represented by a homogeneous coordinate transformation matrix [6]. According to [8], in the original D-H representation, the ssocia the axis of the join to the z axis and each matrix is represented by the product of four basic transformations involving rotations and translations as we can observe in equation (1). Figure 2 shows the D-H parameters with a graphical representation [1]. Figure 4 shows the detail of the movement of the fist representing with the initials N (yaw), S (pitch) and A (Roll). Table 1 shows that you can describe any homogeneous transformation matrix from four basic transformations. Table 1.Basic Transformations of Denavit-Hartenberg [5]. Symbol Meaning \ud835\udc45\ud835\udc67,\ud835\udf03 Rotation around the Z axis by an angle \ud835\udf03 \ud835\udc47\ud835\udc67,\ud835\udc51 Translation along the Z axis by a distance d \ud835\udc47\ud835\udc65,\ud835\udc4e Translation along the X-axis by a distance to \ud835\udc45\ud835\udc65,\ud835\udefc Rotation around the X axis by an angle \ud835\udefc 1421 Ricardo Luiz Ciuccio 1, ETJ Volume 7 Issue 08 August 2022 The calculations corresponding to a generic homogeneous transformation and each of the basic transformations are presented in equations 1 to 5", + " The articulated type of manipulator has its configuration similar to that of a human arm, due to its set of 6 rotational joints, which can be separated into two groups that make up the wrist and those corresponding to the movement of the arm. Figure 8 shows the technical specifications of the robot of the manufacturer YASKAWA-MOTOMAN-GP7, with the dimensions of its structure in millimeters. One of the features that differs from this standard model of yaskawa-MOTOMAN-GP7 robot is the misalignment of the base center with the center of the manipulator end. This misalignment can be seen in Figure 4, which clearly shows that the link on which the handle is located 40 mm to the right with respect to the center of the robot base. To identify the respective joints of the Robot YASKAWA-MOTOMAN-GP7, figure 9 shows the joints j1, j2, j3, j4, j5 and j6 in a squematic way. The approach adopted for the determination of direct kinematics of this robot is part of the preliminary analysis of possible movements and recognition of the types of links and joint components of the system. Then, based on the information acquired, coordinate systems are adopted for the axes to be studied with a view to determining the Denavit-Hartenberg parameters of the robotic arm under study" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002763_eu_1611_fulltext.pdf-Figure101-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002763_eu_1611_fulltext.pdf-Figure101-1.png", + "caption": "Figure 101: The ER fluid flows between the stationary electrodes forming the valve. The pressure drop across the valve can be controlled by varying the electric field strength between the electrodes; thus forming a pressure control valve.", + "texts": [ + "....................................................... 110 Figure 99: Cross-section of the rotary ERF-actuator ...................................................................................................... 110 Figure 100: When an electric field is applied to an ER fluid, the dispersed solid particles line up along the field direction, causing the fluid to get \u201cthicker\u201d [74]. ........................................................................................................... 112 Figure 101: The ER fluid flows between the stationary electrodes forming the valve. The pressure drop across the valve can be controlled by varying the electric field strength between the electrodes; thus forming a pressure control valve. 113 Figure 102: The step response of the linear actuator to a 2 kV/mm ................................................................................. 114 Figure 103: The close-up of the step response of the linear actuator to a 2 kV/mm electric field at 22.75 cc/sec flow rate", + " 113 ER fluids are mostly used in hydraulic application demanding high control bandwidth. Examples include semi-active suspension of vehicles, or clutches that engage/disengage rapidly. When an electrical potential is applied to the electrodes, the resultant electric field across the gap causes a rapid change in the yield stress of the ER fluid. The pressure drop across the length of the valve can be controlled by modulating the strength of the field. Thus, the annular gap works like a pressure control valve that is integrated into the cylinder (Figure 101). Typically, the electrode plates of ERF valves are placed approximately 1 mm apart, and the high voltage potential is around 1 kV; which amounts to an electric field strength in the order of 1 kV/mm. It should be kept in mind that the dielectric breakdown strength of air is about 3 kV/mm [76], and electrical field strength should be kept below this value to avoid arcing. 12.2. SYSTEM IDENTIFICATION The ERF-actuators discussed herein being the first of its kind; no prior information was available on how they would behave", + " All tests were conducted whilst the actuator rod was fixed (i.e. static conditions) to eliminate the effect of fluid flow caused by the piston displacement. When applicable, one of the control inputs was fixed while the other one was varied to isolate the effect of one control input from the other. a) Electric Field Step Input A series of tests measured the actuator\u2019s response to a step electric field input under different flow rates of the pump. The results show that the force profile over time has two distinct responses depending on the flow rate (Figure 101). At low flow rates (e.g. 4.55 cc/sec) the force is saturated at some level, whereas at higher flow rates the force exhibits oscillations around almost the same level regardless of the flow rate. To explain this phenomenon, one needs to understand the mechanisms of the electro-rheological effect. At zero electric field these particles are 115 randomly scattered. In the presence of an electric field, the particles in the suspension are polarized and aligned along the direction of the electric field due to the electric dipole moment and form fibrillated structures" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002354_icstce2023_02020.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002354_icstce2023_02020.pdf-Figure2-1.png", + "caption": "Fig 2. (a) & (b) Design layout of proposed Hexabot", + "texts": [], + "surrounding_texts": [ + "Infusion moulding plan: Another elective arranges and fabricating handle for the balanced Hexabot is implantation moulding. This includes making a shape for each parcel, which is at that point filled with fluid plastic to create the extreme parcel [7]. The moulds can be reused to create gigantic sums of unclear parts, making this handle suitable for high-volume era. The parts can be accumulated and attempted to ensure that they meet the specified points of interest. Infusion moulding can be cost-effective for greater era runs and is suitable for plans that require tall precision and consistency. Delicate mechanical technology: Delicate mechanical autonomy includes the utilize of adaptable and deformable materials to make robots that can adjust to their environment and perform sensitive errands. This innovation has applications in fields such as healthcare, fabricating, and space investigation [8]. 3D printing: 3D printing has revolutionized the way that robots are planned and built. It permits for more complex and customized plans, as well as quicker and cheaper generation [9]. Swarm mechanical technology: Swarm robotics includes the coordination of huge bunches of robots to perform assignments collectively. This innovation has applications in areas such as look and protect, farming, and development [10]." + ] + }, + { + "image_filename": "designv7_3_0001537_f_version_1634787306-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001537_f_version_1634787306-Figure2-1.png", + "caption": "Figure 2. The three kinds of leg topology recruitment: (a) series articulated leg, (b) parallel planar leg, (c) symmetric leg.", + "texts": [ + " The flexion and extension of the leg is achieved by a symmetric structure. This study developed custom actuators consisting of brushless DC motors combined with two-stage integrated custom planetary gearboxes to provide high torque density at a small size and weight. The leg rod and body housing frame are made of carbon and connected by a high-strength aluminum alloy. The hip height is approximately 0.6 m. This study mainly focused on the leg geometry and actuators; therefore, the leg inertia was kept as low as possible to enable fast and efficient leg motion. Figure 2 shows the typical leg design topology. They are series leg (a serial chain of two revolute joints), parallel leg (a parallelogram four-bar), and symmetric leg (a symmetrical rhombus). L1 and L2 are the upper and lower linkage length, respectively, which are equal in the series and parallel leg topologies, and L1 is half of L2 in symmetric leg topology. This study mainly focused on three types of leg topology for proprioceptive force sensitivity, force production, and joint impact mitigation. Proprioceptive force sensitivity means that some forces change at the toe visible to the joint motor, according to Equation (1), where \u2206 f is the force change unit" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure6.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure6.1-1.png", + "caption": "Figure 6.1 Loading Part Analysis Demonstration", + "texts": [ + "7 Mass Property of Forklift Assembly (P84) Figure 5.8 Mass Safety Zone of Forklift (P85) Figure 5.9 Front View of Forklift\u2019s Center of Mass (P86) Figure 5.10 Top View of Forklift\u2019s Center of Mass (P86) Figure 5.11 Top View of Forklift with Stability Triangle Dimension (P87) Figure 5.12 Adjusted Stability Triangles (P88) Figure 5.13 Forklift with 3000kg load (P89) Figure 5.14 Mass Center Positon under 3000kg Load (P90) Figure 5.15 Forklift with 2000kg load (P91) Figure 5.16 Mass Center Positon under 2000kg Load (P92) Figure 6.1 Loading Part Analysis Demonstration (P95) Figure 6.2 Fork Meshing Model (P96) Figure 6.3 Boundary Condition (P96) Figure 6.4 Stress Result of the Fork (P97) Figure 6.5 Strain Result of the Fork (P97) Figure 6.6 Displacement of the Fork (P98) Figure 6.7 Maximum Von Mises Stress Result of the Fork (P98) Figure 6.8 Fatigue Checking of the Fork (P99) Figure 6.9 Meshing Model Using Moderate Elements (P100) Figure 6.10 Meshing Model Using Fine Elements (P100) Figure 6.11 Fine Element Meshing Model Using L= 4mm (P101) Figure 6", + " Scissor lift needs to push up not only the weight of load but also the cabin and the lifting system. We will test how it performs under the pressure and see if it is safe to use. Forklift loading parts are responsible for picking up the load and carry it during the transportation. In this process, there are two kinds of failure: sudden fracture due to the heavy load and fatigue fracture due to the vibration caused by uneven ground during the transportation. We will do stress analysis targeting both conditions. As Figure 6.1 shows, two components will be put under test. They are the fork and the fork support frame. As the result we get from Section 5.2.2, the maximum loading capacity of this forklift is 2000kg. So we will apply 2000kg external load to carry all analysis here. Furthermore, as stated in finite element theory, using different meshing element would cause different analysis results. We will use the actual results to prove this conclusion. This section covers both the static and dynamic (due to fatigue) analyses of the forks" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004479_f_version_1679279622-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004479_f_version_1679279622-Figure4-1.png", + "caption": "Figure 4. The joint with two DoFs.", + "texts": [ + " Two arc guide rails were designed at the end of the arc slider to improve the fault tolerance of the docking. The number of robot modules must be at least three to ensure the stability of the robot\u2019s center of mass. In the series connecting process, two linear servo motors drive the sliding blocks to move on the sliding rail after one robot\u2019s active lock slides into another robot\u2019s arc slider. Then, the pins on the sliding blocks are inserted into the holes of the arc slider, thus achieving a series connection. Figure 4 illustrates the mechanical design of the 2-DoF joint, which is connected to the active lock to achieve a pitch rotation (\u221245\u25e6 to 45\u25e6) and a yaw rotation (\u221215\u25e6 to 15\u25e6). More specifically, the 2-DoF joint of the robot module is composed of two linear motors, four spherical joints, a connecting base, a yaw joint, and a pitch joint. The linear motors (rated voltage: 6 V, length: 50 mm) connect to the connecting base and active lock through the spherical universal joints. Their lengths can be determined to achieve the target pitch and yaw angles based on the kinematic inverse solution [8]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002862_f_version_1441001603-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002862_f_version_1441001603-Figure5-1.png", + "caption": "Figure 5. A mobile robot system equipped with a stereo camera. A patterned marker is used for providing ground truth.", + "texts": [ + " x, y, and \u03b8yaw in the proposed algorithm especially have better performance because the simulation is made for a mobile robot moving on a flat ground. To be clear, a paired t-Test is performed to analyze the performance statistically. As the p-value is 1.1527 \u00d7 10\u221257, the superiority of the proposed algorithm is assured. To validate the performance of the proposed algorithm, experiments with a mobile robot were performed. The mobile robot system, Pioneer 3-AT model [45], is equipped with a stereo vision, Bumblebee XB3 model [46], and a marker system for the ground truth as shown in Figure 5. The XB3 provides the depth value of each pixel. Thus, the sensor produces a 2D image as well as per-pixel depth data with 1920 \u00d7 1080 resolution. A camera is installed on the ceiling for measuring the ground truth pose of the mobile robot as shown in Figure 6a and its sample captured image is shown in Figure 6b. The ground truth system is only able to estimate 3-DoF pose (x, y, \u03b8yaw). Thus, other elements of robot pose (z, \u03b8roll, \u03b8pitch) for ground truth are set to zero because the mobile robot is assumed to move on the flat ground" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003638_38496_FULLTEXT02.pdf-Figure3.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003638_38496_FULLTEXT02.pdf-Figure3.1-1.png", + "caption": "Figure 3.1 nomenclature for spur gear [18]", + "texts": [], + "surrounding_texts": [ + "Gears are mainly used to transmit rotary motion between two shafts. Among different means of mechanical power transmission, gears are most rugged, durable and efficient. Their power transmission efficiency is as high as 98 percent [14]. In addition, as expected the manufacturing cost is also high and increases with the required precision level, which combines high speed, heavy loads and less noise. Incorrect modelling will result to power loss and ultimately damage the components. Therefore, before starting to design it is important to have some basic knowledge of the theory of gear pair teeth in mesh." + ] + }, + { + "image_filename": "designv7_3_0003049_f_version_1515505397-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003049_f_version_1515505397-Figure1-1.png", + "caption": "Figure 1. Kinematic parameters of the underwater snake robot.", + "texts": [], + "surrounding_texts": [ + "The robot is assumed to consist of n rigid links with each of them having length 2l, mass m and moment of inertia J = 1 3 ml2. The links are interconnected by n \u2212 1 joints. The center of mass (CM) of the link is defined as the middle point, since it is assumed that the mass is uniformly distributed, with the total mass of the USR given by nm. The kinematics and dynamics of the robot will be described in terms of the mathematical symbols described in Table 1 and illustrated in Figures 1 and 2. The following vectors and matrices are used in the subsequent sections: A = 1 1 . . . . . . 1 1 , D = 1 \u22121 . . . . . . 1 \u22121 , where A, D \u2208 R(n\u22121)\u00d7n. Furthermore, e = [ 1, . . . , 1 ]T \u2208 Rn, E = [ e 0n\u00d71 0n\u00d71 e ] \u2208 R2n\u00d72 , S\u03b8 = diag(sin \u03b8) \u2208 Rn\u00d7n, C\u03b8 = diag(cos \u03b8) \u2208 Rn\u00d7n, \u03b8\u0307 2 = [ \u03b8\u03071 2, . . . , \u03b8\u0307n 2 ]T \u2208 Rn , K = AT ( DDT )\u22121 D. The kinematics of the robot is derived for a motion in horizontal plane. We assume that the robot is fully immersed in water and has in total n + 2 degrees of freedom (DOF). The parameters \u03b8i and \u03c6i = \u03b8i \u2212 \u03b8i\u22121 represent the link angle and the joint angle of each link, respectively. The link angles and the joint angles are grouped in \u03b8 = [\u03b81, . . . , \u03b8n] T \u2208 Rn and \u03c6 = [\u03c61, . . . , \u03c6n\u22121] T \u2208 Rn\u22121. The position of the CM of the USR pCM \u2208 R2 can be calculated as: pCM = [ px py ] = [ 1 nm \u2211n i=1 mxi 1 nm \u2211n i=1 myi ] = 1 n [ eTX eTY ] , (1) where (xi, yi) are the global frame coordinates of the CM of link i, X = [x1, . . . , xn] T \u2208 Rn and Y = [y1, . . . , yn] T \u2208 Rn. Regarding the hydrodynamic modeling, in [6], it is shown that the global frame forces due to interaction of the links with the water can be assembled in vector form as follows: f = [ fx fy ] = [ fAx fAy ] + [ f I Dx f I Dy ] + [ f II Dx f II Dy ] , (2) where the added mass effects fAx and fAy in x and y direction, respectively, are given by[ fAx fAy ] = \u2212 [ \u00b5n (S\u03b8) 2 \u2212\u00b5nS\u03b8C\u03b8 \u2212\u00b5nS\u03b8C\u03b8 \u00b5n (C\u03b8) 2 ] [ X\u0308 Y\u0308 ] \u2212 [ \u2212\u00b5nS\u03b8C\u03b8 \u2212\u00b5n (S\u03b8) 2 \u00b5n (C\u03b8) 2 \u00b5nS\u03b8C\u03b8 ] [ Va x Va y ] \u03b8\u0307, (3) where Va x = diag (Vx,1, . . . , Vx,n) \u2208 Rn\u00d7n, Va y = diag ( Vy,1, . . . , Vy,n ) \u2208 Rn\u00d7n and [Vx,i, Vy,i] T represents the constant and irrotational ocean current effects. Furthermore, the linear and nonlinear drag forces on the robot are given by [ f I Dx f I Dy ] = \u2212 [ ctC\u03b8 \u2212cnS\u03b8 ctS\u03b8 cnC\u03b8 ] [ Vrx Vry ] , (4) [ f II Dx f II Dy ] = \u2212 [ ctC\u03b8 \u2212cnS\u03b8 ctS\u03b8 cnC\u03b8 ] sgn ([ Vrx Vry ]) [ Vrx 2 Vry 2 ] , (5) where the relative velocities are given by[ Vrx Vry ] = [ C\u03b8 S\u03b8 \u2212S\u03b8 C\u03b8 ] [ X\u0307\u2212Vx Y\u0307\u2212Vy ] . (6) In addition, the fluid torques on all links are \u03c4 = \u2212\u039b1\u03b8\u0308\u2212\u039b2\u03b8\u0307\u2212\u039b3\u03b8\u0307|\u03b8\u0307|, (7) where \u039b1 = \u03bb1In, \u039b2 = \u03bb2In and \u039b3 = \u03bb3In. The fluid parameters due to the drag and added mass effects are denoted by ct, cn, \u03bb2, \u03bb3 and \u00b5n, \u03bb1, respectively. For more details see [6]. Combining the kinematics and the hydrodynamic model, in [6,21,22], it is shown that the equations of motion of an USR can be expressed as follows:[ p\u0308x p\u0308y ] = \u2212Mp [ k11 k12 k21 k22 ] [ lKT(C\u03b8 \u03b8\u0307 2 + S\u03b8 \u03b8\u0308) lKT(S\u03b8 \u03b8\u0307 2 \u2212C\u03b8 \u03b8\u0308) ] \u2212Mp [ k12 \u2212k11 k22 \u2212k21 ] [ Va x Va y ] \u03b8\u0307+ Mp [ eTfDx eTfDy ] , (8) M\u03b8\u03b8\u0308+ W\u03b8\u03b8\u0307 2 + V\u03b8 \u03b8\u0307+ \u039b3|\u03b8\u0307|\u03b8\u0307+ KDxfDx + KDyfDy = DTu, (9) where fDx = f I Dx + f II Dx and fDy = f I Dy + f II Dy represent the drag forces in the x and y directions and u \u2208 Rn\u22121 the control input. For more details regarding the derivation of the vectors k11, k12, k21 and k22 and the matrices Mp, M\u03b8 , W\u03b8 , V\u03b8 , KDx and KDy, see [21,22]." + ] + }, + { + "image_filename": "designv7_3_0003610_ASET_5-1160-1168.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003610_ASET_5-1160-1168.pdf-Figure5-1.png", + "caption": "Fig. 5: Front view of sample/reagent arm", + "texts": [ + " Based on the number of samples, the testing cycle can be reduced through the programming. The Robot Arm which is handling the samples and reagents has a 4 Degrees of Freedom (DOF) and the 3 rd Arm is used to stir the reaction cell content and move the contents to the micro flow cell for the processing. Each arm has separate pneumatic pipettor. The task of handling each arm contains the movement of in and out. It encompasses x-y-z or z-\u03b8 sample, reagent arm movement and the conveyance of samples arm to the reaction cells. Figure 5 and 6 shows CAD drawing of Robotic arm in front and side view. Both the sampling and Reagent arm looks the same. At the end of the arm, the liquid handler, i.e., pneumatic pipettor is attached. Table 1 shows the specification of analytical plate and arm dimensions. This system can able to perform 36 tests per patient. So totally it runs up to 1152 tests per batch. Controlling Unit consists of the micro controller and all its associated circuitries. This unit controls the entire system. For controlling the arm we are proposing the scheduling algorithm" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure23.12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure23.12-1.png", + "caption": "FIGURE 23.12. Maximum slope for a vehicle with internal combustion engine.", + "texts": [ + "3 This strategy works only in the case of vehicles with high power/ weight ratio: In low powered vehicles, this \u201ceconomy\u201d gear would be very difficult to use since any increase of the required power, e.g., due to a slight grade, headwind, etc., would compel a shift to a shorter gear. Undergearing may be a necessity in this case. OF THE TRANSMISSION RATIOS The maximum grade that can be managed with a given gear ratio may be obtained by plotting the curves of the required power at various values of the slope and looking for the curve that is tangent to the curve of the available power (Fig. 23.12). The slope so obtained is, however, only a theoretical result, since it can be managed only at a single value of the speed: If the vehicle travels at a higher speed, it slows down because the power is not sufficient, but if its speed is reduced the power is insufficient and the vehicle slows down further: The condition is therefore unstable and the vehicle stops. must be above that of the required power in a whole range of speeds, starting from a value low enough to assure that starting on that slope is possible" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000808_f_version_1623211511-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000808_f_version_1623211511-Figure1-1.png", + "caption": "Figure 1. The movements of the accompanying robot and the user. (a) the robot translates and rotates to the target position; (b) the user translates without rotation; (c) the user rotates in place without translation; (d) the user translates and rotates.", + "texts": [ + " For example, if the robot tracks the course of the user\u2019s movement, it may not be able to determine whether the user is moving backward or turning around and subsequently moving forward. To date, a single method for a robot to follow a user in any designated position has not been developed. This paper proposes a user local coordinate-based method to satisfy this demand. To prove its concept, we implemented a system and assessed its performance in our gait lab. The concept of the proposed accompanying method is that the robot should move to the specified position with respect to the user\u2019s local coordinate system (LCSU). As shown in Figure 1a, the objective is to make \u21c0 RC (the current position and orientation of the robot relative to the user) approach \u21c0 RT (the target position and orientation relative to the user), i.e., to make the position difference \u2206 \u21c0 RM approach the zero vector as given in Equation (1). Its underlying tasks include determining the target position, obtaining the robot\u2019s position, calculating the position difference between the target and the accompanying robot in LCSU , and moving the robot in the robot coordinate system (LCSR) to reduce the position difference", + ", \u2206 \u21c0 RM = \u21c0 RT \u2212 \u21c0 RC = [ 0 0 1 ] (1) where Ow : World coordinate system (WCS) OU : User\u2032s local coordinate system (LCSU) OR : Robot\u2032s local coordinate system (LCSR) \u21c0 RT : Robot\u2032s target position relative to the user \u21c0 RC : Robot\u2032s current position relative to the user \u2206 \u21c0 RM : Position di f f erence For convenience, homogeneous coordinates are used. In general, the user is moving, so LCSU and \u21c0 RC in LCSU will change even when the robot is stationary. The three moving scenarios are discussed below. The first scenario is that the user performs a translation without rotation, as shown in Figure 1b. Assuming the user translates from OUT0 to OUT1 , let \u21c0 OUT0OUT1 = [ \u2206Xt \u2206Yt ] in the world coordinate system (WCS), and view the movement from the perspective of LCSU . \u21c0 RC1 = \u21c0 OUT1ORC0 = \u21c0 RC0 1 0 0 0 1 0 \u2212\u2206Xt \u2212\u2206Yt 1 = XC0 YC0 1 T \u2212 \u2206Xt \u2206Yt 1 T (2) The second scenario is that the user performs a rotation in place without translation, as shown in Figure 1c. \u21c0 OUT0OUT1 rotates with \u03b1r in WCS and is viewed from LCSU . \u21c0 RC1 = \u21c0 OUT1ORC1 = \u21c0 OUT0ORC0 rotate \u2212 \u03b1r = \u21c0 RC0 cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 \u2212 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 0 0 1 = XC0 YC0 1 T\u2212 cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 0 0 1 = XC0 cos \u03b1r + YC0 sin \u03b1r \u2212XC0 sin \u03b1r + YC0 cos \u03b1r 1 T (3) LCSR is also rotated by \u03b1r. The third scenario is that the user translates and rotates, as shown in Figure 1d; then, \u21c0 RC1 = \u21c0 RC0 cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 \u2212 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 \u2212\u2206Xt \u2212\u2206Yt 1 = XC0 YC0 1 T cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 \u2212 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 \u2212\u2206Xt \u2212\u2206Yt 1 = XC0 YC0 1 T cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 \u2212 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 0 0 1 \u2212 \u2206Xt \u2206Yt 1 T (4) The third scenario is the general case. Combined with Equation (1), this leads to \u2206 \u21c0 RMU , and the position difference in LCSU is \u2206 \u21c0 RMU = \u2206XU \u2206YU 1 T = \u21c0 RT \u2212 \u21c0 RC1 = XT YT 1 T \u2212 XC0 YC0 1 T cos(\u2212\u03b1r) sin(\u2212\u03b1r) 0 \u2212 sin(\u2212\u03b1r) cos(\u2212\u03b1r) 0 0 0 1 \u2212 \u2206Xt \u2206Yt 1 T (5) LCSR is also rotated by \u03b1r" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002826_f_version_1691055888-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002826_f_version_1691055888-Figure9-1.png", + "caption": "Figure 9. Workspace Analysis: (a) schematic diagram of endpoints; (b) trainer workspace.", + "texts": [ + "3 s, as there is n relative d splacement between the slider and chute of the proxi al i terphal ngeal joint in the f ur-finger actuator during this time period. Figure 8. Angular displacement curve of each joint of hand. 3.3. Workspace Analysis The workspace of an exoskeleton is an important indicator used to evaluate its feasibility. It represents the motion performance of the robot and directly influences its practical application value. In the elbow joint rehabilitation trainer, we take the palm position point P of the trainer as the endpoint (Figure 9a). By imposing angle constraints on the wrist and elbow joints and using the Monte Carlo random sampling method, we generate a large number of endpoint positions to visualize the robot\u2019s workspace (Figure 9b). Figure 8. Angular displacement curve of each joint of hand. In Figure 8, the angular displacement curves of each joint of the hand gently change, and the ranges of motion of the metacarpophalangeal joint, proximal interphalangeal joint, and thumb interphalangeal joint are 0~84\u25e6, 0~73\u25e6, and 0~49\u25e6, respectively. The angular displacement curve of the proximal interphalangeal joint stays at the maximum angle for about 0.3 s, as there is no relative displacement between the slider and chute of the proximal interphalangeal joint in the four-finger actuator during this time period. The workspace of an exoskeleton is an important indicator used to evaluate its feasibility. It represents the motion performance of the robot and directly influences its practical application value. In the elbow joint rehabilitation trainer, we take the palm position point P of the trainer as the endpoint (Figure 9a). By imposing angle constraints on the wrist and elbow joints and using the Monte Carlo random sampling method, we generate a large number of endpoint positions to visualize the robot\u2019s workspace (Figure 9b). Electronics 2023, 12, x FOR PEER REVIEW 9 of 17 thumb training simulation cycle of 3.97 s can be obtained. After a complete hand grasping simulation, the angular displacement curves of the metacarpophalangeal joint of the index finger, the proximal interphalangeal joint of the index finger, and the interphalangeal joint of the thumb can be obtained. The simulation curve is shown in Figure 8. In Figure 8, the angular displacement curves of each joint of the hand gently change, and the ranges of motion of the metacarpophalangeal joint, proximal interphalangeal joint, and thumb interphalangeal joint are 0~84\u00b0, 0~73\u00b0, and 0~49\u00b0, respectively", + "3 s, as there is no relative displacement between the slider and chute of the proximal interphalangeal joint in the four-finger actuator during this time period. Figure 8. Angular displacement curve of each joint of hand. 3. . Workspace Analysi The workspace of an exoskel ton is an important indicator used to evaluate its feasibility. It represents the motion performance of the robot a i tical a plication value. In the elbow joint rehabilitation trainer, we tak the palm p siti n point P of the t ainer as the e dpoint (Figure 9a). By imposing a gle constraints on he wrist and elbow joints and using th Monte Carl random sampling method, we gener te a large number of e d in po i ion to visualize the rob t\u2019s workspace (Figure 9b). Electronics 2023, 12, 3326 10 of 17 Electronics 2023, 12, x FOR PEER REVIEW 10 of 17 As shown in the figure, the simulated workspace results align with the human workspace and conform to the physiological parameters of the human body. This result proves that the robot is capable of meeting the requirements of rehabilitation training. 4. Prototype Experiment After completing the motion simulation of the mechanism, a prototype of a portable elbow-linked upper limb rehabilitation robot was produced, and the prototype had adjustable settings to accommodate different users" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001553_f_version_1640683912-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001553_f_version_1640683912-Figure9-1.png", + "caption": "Figure 9. Temperature distribution model for the external side of the control computing unit. The simulation results show the high efficiency of the developed architecture in the distribution of thermal loads.", + "texts": [], + "surrounding_texts": [ + "In accordance with the developed methodology, a control computing complex was developed for AnyWalker (Figure 5). According to the methodology (Step 1), evaluation of parameters based on the analysis of technical and economic requirements and operating conditions has been done: The first parameter, general technical requirements, for AnyWalker assumed a multipurpose application in heterogeneous operating conditions and interaction with IoT devices. It was necessary to provide the possibility of connecting a large number of sensors from different manufacturers. Therefore, the choice was stopped on ROS, as a platform in the open database of which there are interfaces for the overwhelming number of sensor manufacturers. The second parameter, assessment of the number of connected sensors, lead to the choice of high bandwidth onboard computer network based on UART as the number of connected sensors would be large. The third parameter, determination of the number of drives and non-motorized degrees of freedom, was equal to 27 motorized DoF, so it was necessary to provide synchronous operation of different drives with low latency. A search was made for variants of the distribution of the architecture of the computing complex. The first evaluated version of the controller was STM32F4DISCOVERY Discovery kit based on a microcontroller STM32F407VG. The flash memory of the microcontroller contains the program code for interacting with EPOS2 and GL-SVG-02/2, as well as the code of the linear quadratic controller. This option is the simplest and most compact of all evaluated as the delays are minimal due to the simplicity of the system. However, when scaling the system, it will be necessary to control three flywheels at once, it will be necessary to connect a large number of sensors and increase the amount of program code for the functioning of the remaining systems of the robotic walking platform. In this case, a better choice would be to connect all devices to a controller with a Robotic Operating System, ROS. This was done in the following configuration. Therefore, next stage of research was serial connection of two software controllers, physically located on different platforms. A Raspberry Pi 3 minicomputer with the Ubuntu 16.04 operating system and the ROS Kinetic framework installed on it was connected to the STM USART interface. An ASUS GL553V laptop with an Intel Core i7-7700HQ 2.80 GHz processor and 16 GB of RAM with the Windows 10 Home operating system, as well as the MATLAB version 2017b environment, was connected to the Raspberry Pi 3 via the UTP LAN interface. The third controller option is STM32 NUCLEO-144 BOARD instead of STM32F4DISCO VERY in the second variant. The reason for this choice is the presence of an RJ45 connector on the Ethernet board, which allows one to increase the speed of the connection between STM and Raspberry Pi 3 from 4 to 100 Mbit/s. In this version STM, Raspberry Pi 3 and laptop are connected to the switch. The choice was made on the third variant of the architecture implementation, since this option allowed for the transmission of significant parameters of the state of the robotic system with a frequency of more than 100 Hz and the frequency of the control cycle of the stabilization algorithm of more than 200 Hz. The evaluation of the fourth parameter, assessment for the need of rapid prototyping, lead to the conclusion that it is extremely important to be able to test various configurations during the prototyping process, which was made possible due to the ROS-MATLAB linkage and MATLAB code generation. For the fifth parameter, assessment of the criticality of fault tolerance requirements, since reliability is a key requirement for the hardware and software architecture of the walking platform, a CAN Network with high fault tolerance was used to organize the on-board network. For the sixth parameter, determination of computing power for the operation of the system, a large computing power was required for robot stabilization and computer vision sensors operation processing, therefore an external MATLAB Speedgoat computer was accounted in the architecture. For the seventh parameter, evaluation of the criticality of the noise immunity of the device, it was suggested that AnyWalker could operate in severe operating conditions with electromagnetic fields of high intensity, so the CAN interface was chosen to provide the noise immunity of the device. For the eighth parameter, evaluation of the limitation on the distance between interacting modules, due to the compactness of the placement of onboard computing modules of AnyWalker, CAN was used without a significant loss of data transfer speed on board the robot. For the ninth parameter, assessment of real-time requirements, The necessity of estimating the permissible delay in the feedback loop was determined. After the analysis, it was concluded that those delays should not exceed 200 ms. At Step 2 of the methodology, the distribution of functional tasks was done for each of the three levels: 1. The reactive level is implemented on the STM32F407 micro controller. The IMU6050based accelerometers/gyroscopes are polled via the I2C bus and the data is filtered using the Madgwick sensor fusion algorithm. The movement of the flywheels and the calculation of the speed are carried out using Maxon EPOS2 controllers with Maxon EC motors. Dynamixel MX106T actuators for robot legs are controlled via RS485, using a MAX485-based converter. 2. The executive level is based on the Raspberry Pi controller with the Robot Operating System installed and is connected to the reactive level via the RS-485 bus. This level implements a simple autonomous behavior, a state machine, provides security and emergency shutdown. Data transfer to the cloud is carried out using Bluetooth, WiFi or Ethernet, if necessary. 3. The application layer provides software installed on a personal computer or smartphone, fully or partially located in the cloud. The application layer provides a high- level user interface, supports the API of cloud voice recognition services, collects data from sensors and control commands for machine learning purposes, connects several AnyWalker robots to provide a pattern of collective behavior. It is possible to use algorithmic control support as an information service that allows third-party developers to use the API to solve application problems. An application for the Android platform has also been developed to send motion commands to AnyWalker and display the result. At Steps 3\u20134 of the methodology, the choice of data exchange technologies, microprocessors, based on the obtained estimates of parameters was solved (Figure 6). At Step 5, the application development and cloud services configuration were done [70\u201372]. At Step 6, the architecture was finally implemented. The core components in the scheme are the STM32F407 micro-controller for the periphery and the Raspberry Pi 3 microcomputer serving as a top-level controller with interfaces for the inter-operation of control software and a vast majority of clients with peripheral devices. The controller of the periphery interacts wia the SPI protocol with a 9-axis inertial navigation system consisting of gyroscopes, accelerometers and magnetometers, an MPU9250 chip. The equipment installed in the robot is controlled via the EPOS2 motor drivers with the CAN communication protocol. The legs of the robot are driven with Dynamixel MX-106 servomotors, the connection of which is done with the RS-485 protocol. The 6 elements per foot servo series is used. Both buses are connected to two independent UART interfaces of the micro-controller. The UART interface is used for the interaction of the upper-level controller and the controller of the periphery. The peripheral control codes are sent with that interface. The data from the INS sensors, the flywheels rotation speed, the values of the temperature and the servo loads are requested with UART as well. The STM32F407 controller is also connected via USB for debugging and downloading updated software using the STLink v2 protocol. Clients which implement various logic elements are also provided by the scheme. The high-level controller is connected to the clients via an Ethernet channel or a wireless WiFi network. In accordance with the chosen architecture, the main mathematical calculations are performed in a cloud environment, a high-speed data exchange with the robot board is provided via a broadband communication channel. At the same time, the computers on board the robot control the servos and provide primary filtering of data coming from the sensors. For example, a separate ARM computer is installed on the gyroscopes and accelerometers unit. The cloud infrastructure in this robot provides application software interfaces for programming the robot in the MATLAB environment and controlling the robot using an Android tablet. Figure 7 demonstrates AnyWalker operating under synthesized cloud computing architecture in the process of climbing an obstacle. The modeling of the process of head load distribution was performed to assess the characteristics of the computing complex under the synthesized architecture. The initial data for modeling were as follows: \u2022 The value of the medium temperature is 50 \u00b0C; \u2022 The value of the peak processor power of 65 Watts; \u2022 The value of the peak power on the converter is 40 Watts; \u2022 The value of the peak power on the input filter is 6 Watts. The results of the scattering simulation are shown in the Figures 8 and 9. The simulation results show the high efficiency of the developed architecture in the distribution of thermal loads. The results obtained were used to design the architectures of cloud distributed computing systems of two other walking robots (Figures 10 and 11). Thus, a design methodology for constructing a three-level control architecture for walking robots with a reactive, executive and application level has been developed." + ] + }, + { + "image_filename": "designv7_3_0000727_f_version_1660900350-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000727_f_version_1660900350-Figure1-1.png", + "caption": "Figure 1. Diagram of the vehicle bicycle model.", + "texts": [ + " Contents of Paper This paper consists of six sections: Section 2 discusses vehicle modeling. Next, Section 3 deals with the design of the vehicle lateral motion controller to comply with the yaw rate criterion. Section 4 also presents a newly designed torque distribution algorithm. Then, Section 5 evaluates the effectiveness of the proposed algorithm through several evaluation factors in the simulation study, and Section 6 concludes the paper. 2. Vehicle Modeling The vehicle bicycle model assumes that left and right wheels are lumped together into a single wheel [15]. In this paper, Figure 1 represents a vehicle bicycle model. Since it is assumed that the wheel is located on the center line, the concentrated tire lateral forces Fy f and Fyr are expressed in the front and rear tire coordinate systems, respectively. Additionally, this vehicle bicycle model assumes that the vehicle motion is restricted to Electronics 2022, 11, 2589 3 of 12 the plane and that there is no vertical movement. In the car body coordinate system, the moment and lateral force balance equations are derived as: Iz ", + " vy + rvx ) =Fy f + Fyr (1) where Iz is the vehicle yaw moment of inertia, Mz additional yaw moment, and m the total mass of the vehicle. Additionally, l f and lr are the center of gravity (CG)-front and CG-rear axle distances, respectively: L = l f + lr. In (1), the concentrated tire lateral forces on the front and rear axles Fy f and Fyr can be derived as follows: Fy f = ( mlray + Iz . r + Mz ) /L Fyr = ( ml f ay \u2212 Iz . r\u2212Mz ) /L (2) Electronics 2022, 11, x FOR PEER REVIEW 3 of 13 The vehicle bicycle model assumes that left and right wheels are lumped together into a single wheel [15]. In this paper, Figure 1 represents a vehicle bicycle model. Since it is assumed that the wheel is located on the center line, the concentrated tire lateral forces \ud835\udc39\ud835\udc66\ud835\udc53 and \ud835\udc39\ud835\udc66\ud835\udc5f are expressed in the front and rear tire coordinate systems, respectively. Additionally, this vehicle bicycle model assumes that the vehicle motion is restricted to the plane and that there is no vertical movement. In the car body coordinate system, the moment and lateral force balance equations are derived as: ( ) z yf f yr r z y x yf yr I r F l F l M m v rv F F = \u2212 + + = + (1) where \ud835\udc3c\ud835\udc67 is the vehicle yaw moment of inertia, \ud835\udc40\ud835\udc67 additional yaw moment, and m the total mass of the vehicle" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000534_793a1a30cd9ceec0.pdf-Figure17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000534_793a1a30cd9ceec0.pdf-Figure17-1.png", + "caption": "Fig. 17. Top and Side view of the new Sokolov propeller.", + "texts": [ + " 16 is first simulated in rotating propeller model with 615 rpm inserted as the input rotation rate of the moving reference frame. It is found that the theoretical rotational velocity is insufficient to provide the thrust. This is expected as the theoretical calculation has not taken the viscous drag generated by the propeller into account. Through the method of trial and error, the required 5.4 N thrust is found to be generated by the benchmark propeller when the rotation rate increases to 7750 rpm. This is then followed by the testing of Sokolov propeller (Fig. 17) at both rpms. The thrust results are tabulated in Table 2. By setting the rotation rate of both rotors to be zero, the drag coefficient of WL-V303 Seeker quadrotor can be simulated in drone model to determine the forward thrust required. At a cruising velocity of 5 m/s, the CD of the drone installed with a rectangular payload is found to be 1.09. Provided the total frontal area of the drone is 0.192 m2, using Eq. (11), the required forward thrust to counteract the drag will be 0.31 N. Since the drone is simulated in half, there are only two propellers in the model" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002915_f_version_1682417870-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002915_f_version_1682417870-Figure3-1.png", + "caption": "Figure 3. Model of the end effector for installation of electrical spacers. Side-operating sub-assembly that holds spacer jaw and tightens it (top left image). Motor plate and screw wrench (bolt tool) are used to tighten spacer jaw and they are a part of the side-operating sub-assembly (top center image). End effector adapter is used to connect end effector to robot arm flange (top right image). Complete rendered CAD model of the proposed specialized end effector for spacer installation (bottom image).", + "texts": [ + " There is another requirement that the end effector must adapt to. According to the specification for the robot arm, the end effector must comply with a weight limit of 5 kg total weight, including the electrical spacer. The heaviest mass of the electric spacer predicted in this work is 1.5 kg. Thus, the mass of the end effector must be less than the limit of 3.5 kg. Each of these points is addressed by the design of the newly developed end effector. Its model and model components are shown in Figure 3. To accommodate the varying lengths of the spacer, the end effector is divided into three distinct subassemblies (see Figure 3). Two subassemblies are identical and are designed to operate the opposite sides of the spacer, while the third subassembly of the end effector is designed to be positioned between these two identical subassemblies and is prepared for installation on the robot arm flange. All three subassemblies are designed to run on two guides that hold all three parts as a whole. Each of these subassemblies can be fixed at any point on the guides, so that the spacers of different length can be installed. Prior to installation, the spacer jaws must be held open (see Figure 2) to allow the spacer to enclose the conductors of the power line" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001743_9312710_09262869.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001743_9312710_09262869.pdf-Figure6-1.png", + "caption": "FIGURE 6. (a) CAD and (b) meshed model of the suction module.", + "texts": [ + " If the oscillating system is driven by an external force at the natural frequency of the system, then the system is under resonance and fail. Even though the structural platform of the robot is made rigid, cleaning pay load and friction on the surface may add additional load to the motor and cause failure due to resonance. Therefore, during locomotion and transformation, the actuation speed of the motors attached to wheels and the hinged joints must be set less than the natural frequency of the system to avoid the structural resonance. Three dimensional CAD model of the structural platform is built, as shown in Figure 6. A frequency (modal) analysis of the platform is carried out in ANSYS Workbench. For this analysis, the material properties including density, elastic modulus, Poision\u2019s ratio are considered as 1.24 g /cm3, 0.3, and 3.36 GPa, respectively. With these material, boundary and load settings, a modal (free vibration) analysis is carried out in Workbench environment to obtain the natural frequencies and mode shapes of the platform. The first three natural frequencies are as shown in Figure 7. The first two natural modes represents the symmetrical bending body modes of the platform" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002245_80058_FULLTEXT01.pdf-Figure2.8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002245_80058_FULLTEXT01.pdf-Figure2.8-1.png", + "caption": "Figure 2.8: Elastic and shear moduli of wood in different directions.", + "texts": [ + "1 Orthotropic Elasticity Wood can be considered a naturally occurring composite composed of tube-shaped cells within a lignin matrix. As a result of the structure, wood has different properties in different directions [5]. The wood itself can be considered an orthotropic material with three material principal material axes. The first one in the longitudinal direction, and the other two in the tangential and radial direction [13]. The principal material directions can be seen in Figure 2.7. The stiffness and shear modulus in different directions is illustrated in Figure 2.8. 15 16 Orthotropic materials are materials in which there are at least two planes of symmetry, where the material properties are independent of the direction within each plane [23]. The fundamental Hooke\u2019s law can for an orthotropic material be defined as, in compliance form [24]: [ \ud835\udf00\ud835\udc3f \ud835\udf00\ud835\udc45 \ud835\udf00\ud835\udc47 \ud835\udefe\ud835\udc3f\ud835\udc45 \ud835\udefe\ud835\udc3f\ud835\udc47 \ud835\udefe\ud835\udc45\ud835\udc47] = [ 1 \ud835\udc38\ud835\udc3f \u2212\ud835\udf08\ud835\udc45\ud835\udc3f \ud835\udc38\ud835\udc45 \u2212\ud835\udf08\ud835\udc47\ud835\udc3f \ud835\udc38\ud835\udc47 0 0 0 \u2212\ud835\udf08\ud835\udc3f\ud835\udc45 \ud835\udc38\ud835\udc3f 1 \ud835\udc38\ud835\udc45 \u2212\ud835\udf08\ud835\udc47\ud835\udc45 \ud835\udc38\ud835\udc47 0 0 0 \u2212\ud835\udf08\ud835\udc3f\ud835\udc47 \ud835\udc38\ud835\udc3f \u2212\ud835\udf08\ud835\udc45\ud835\udc47 \ud835\udc38\ud835\udc45 1 \ud835\udc38\ud835\udc47 0 0 0 0 0 0 1 \ud835\udc3a\ud835\udc3f\ud835\udc45 0 0 0 0 0 0 1 \ud835\udc3a\ud835\udc3f\ud835\udc47 0 0 0 0 0 0 1 \ud835\udc3a\ud835\udc45\ud835\udc47] [ \ud835\udf0e\ud835\udc3f \ud835\udf0e\ud835\udc45 \ud835\udf0e\ud835\udc47 \ud835\udf0f\ud835\udc3f\ud835\udc45 \ud835\udf0f\ud835\udc3f\ud835\udc47 \ud835\udf0f\ud835\udc45\ud835\udc47] (3) With notations for directions according to Figure 2.8. The compliance matrix consists of 12 variables but due to symmetry requirements, relations between the Poisson\u2019s ratios are given as: \ud835\udf08\ud835\udc3f\ud835\udc45 \ud835\udc38\ud835\udc3f = \ud835\udf08\ud835\udc45\ud835\udc3f \ud835\udc38\ud835\udc45 \ud835\udf08\ud835\udc3f\ud835\udc47 \ud835\udc38\ud835\udc3f = \ud835\udf08\ud835\udc47\ud835\udc3f \ud835\udc38\ud835\udc47 \ud835\udf08\ud835\udc45\ud835\udc47 \ud835\udc38\ud835\udc45 = \ud835\udf08\ud835\udc47\ud835\udc45 \ud835\udc38\ud835\udc47 (4) thus, reducing the number of independent variables to 9. 17 2.5.2 Continuum Damage Mechanics Continuum Damage Mechanics (CDM) is a way to model progressive material degradation occurring during a deformation process. The method has been used for many different applications in connection to numerical simulation methods [25]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002964_9668973_09764737.pdf-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002964_9668973_09764737.pdf-Figure5-1.png", + "caption": "FIGURE 5. Deformation Analysis.", + "texts": [ + " Moreover, the rotation was jerky and uncontrolled. To address these limitations, a new design with four wheel architecture is proposed.We conduct a deformation and strain analysis on the bogie of the first version and on the wheel frame of the second version of the rover keeping the pivot bar as a fixed support. The simulation was done based on the equation 1 where E denotes elasticity, \u03c3 denotes stress and \u03b5 denotes strain. E = \u03c3 \u03b5 (1) VOLUME 10, 2022 50733 It is observed from the deformation analysis (see Figure 5) that the maximum deformation under the critical load with a safety factor of 4 is 0.17 mm and 0.16 mm respectively. But significant change is found in strain analysis (see Figure 6) that maximum strain in the first version is found in the bent portion of the bogie, which leads to buckling. In the second version however, the maximum strain is observed at the bottom of the wheel frame, which is certainly not a critical position. This frame can tolerate the reaction force without developing any buckling and the rover can withstand impact using a four-wheel mechanism" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001067_67b45fa31ecd8a42.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001067_67b45fa31ecd8a42.pdf-Figure1-1.png", + "caption": "Figure 1: Flexible joint single link manipulator driven by brushed DC motor [9]", + "texts": [ + " The aim of this study was to suggest a new method to design controller for flexible joint robot. Firstly, the controller designed to transform the electrical system to LPF with a suitable small time constant. Secondly, a control law derived for the mechanical system utilizing theory of SMC, after linearizing the mechanical system model, which it is capable to force the mechanical state to the desired reference in spite of the presence of uncertainty system model. The dynamic equation of the flexible joint single link manipulator driven electrically as clarified in Figure 1 can be modelled mathematically as the following equations: For the link, the mathematical model based on Newton\u2019s law is [9, 23]; \u0308 ( ) ( ) \u0308 ( ( ) ( )) } (1) Generally, the torque resulted from a DC motor is proportional to , and magnetic field strength. Let's say constant magnetic field, proportional to only by as interpreted in the following equation: where the controller for armature-DC motor system is the input voltage , is proportional to the angular velocity of the shaft by a constant factor ", + "( ) / (27) The flexibility of joint can cause oscillations in manipulators so that, it is considered as a problem. A robust nonlinear controller SMC is proposed for stabilization and prevent the oscillation while the flexible joint manipulator reaches the desired angle. For system closed loop, the stability analysis is performed. The suggested controller requires information of feedback for each velocity and position on link, motor in addition to armature current. For a flexible joint single link robot as shown in Figure 1 with nominal system parameter given in Table 1, simulation results indicate a good performance of designed controller. In order to show the effectiveness of the designed controller, four simulation cases are performed for the flexible joint manipulator with single link.The simulation results in these four cases represent the system states variations, the sliding variable and the control voltage . All of them plotted versus time. These states are illustrated above as ( ), ( ), ( ), ( ) and ( ) respectively which are stabilized and converge to desired value" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002655_8948470_09115614.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002655_8948470_09115614.pdf-Figure4-1.png", + "caption": "FIGURE 4. Schematic representation of LOS algorithm with acceptance circle option.", + "texts": [ + " The wind forces and moment acting on the ship can be estimated as [27]: XW = 1 2 CX\u03c1aV 2 r AF YW = 1 2 CY\u03c1aV 2 r AL NW = 1 2 CN\u03c1aV 2 r ALL (5) The corresponding physical meaning of each symbol is listed in Table 2. C. PATH FOLLOWING METHOD As mentioned in Section III-A, it is practical that the ship approaches the dock area with a certain angle, along with an imaginary line. To ensure the ship can follow the pre-planned path, the LOS algorithm with acceptance circle option is applied, as shown in Fig. 4. Suppose the ship position (x, y) and its velocityU are given, the distance error e, i.e., (the normal distance to the planned path) can be calculated. By defining a circle with a radius R = \u03b1e (\u03b1 > 1), we can obtain the VOLUME 8, 2020 110143 position (xi, yi) of the intersection point Q between the circle and the path (choose the point closer to the destination) by solving the following equations: (xi \u2212 x)2 + (yi \u2212 y)2 = R2 xi \u2212 xp yi \u2212 yp = k (6) where (xP, yP) is the position of the way point P on the planned path; k is a constant representing the slope of the planned path" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.4-1.png", + "caption": "Fig 5.4 Accumulator", + "texts": [], + "surrounding_texts": [ + "The Accumulator is used to store pressurized air and to provide a short-term supply of compressed air to a particular device. It has one connection port labelled Accumulator Port." + ] + }, + { + "image_filename": "designv7_3_0000188_JAES-V8N1P283Y23.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000188_JAES-V8N1P283Y23.pdf-Figure2-1.png", + "caption": "Fig. 2. Motion positions of 2DOF robot in pre-TO", + "texts": [ + "097( ); 10( ); 4.48( ); 0; 0; C C L m L m L m G N G N = 10( )F N . Accordingly, the force and moment values at the respective position are determined as follows = = = = = = 1 1 1 2 2 2 0; 24.48( ); 8.486( ); 0; 14.48( ); 2.34( ); X Y Z X Y Z F F N M Nm F F N M Nm Consider the dynamic analysis problem with the start position (P1) corresponding to = = 00 and the material of links is aluminum 6061. Joint 1 and joint 2 are driven with velocities = 1 ( ) 12 v rad s and = 2 ( ) 18 v rad s respectively. Fig. 2 (a, b, c) describes the corresponding position of the robot on the moving trajectory (start position, middle position and end position). Based on the above motion trajectory, the force and moment values acting on joints 1 and 2 are specifically determined as shown in Fig. 3 and Fig. 4, respectively. 269 Duong Xuan Bien, Pham Dac Phong, Pham Hoang Nam, and Le Thanh Hung, \u201cInverse Dynamics Analysis of the Robot Arm Using the Topology Optimization,\u201d International Research Journal of Advanced Engineering and Science, Volume 8, Issue 1, pp" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004303_1145_3522784.3522786-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004303_1145_3522784.3522786-Figure1-1.png", + "caption": "Figure 1: The MAV equipped with the sensors used in the ODAdataset, and the embeddedCPU for data collection. The IMU is built in the DVS sensor.", + "texts": [ + "14 LTS. For the purpose of obstacle detection and avoidance in MAVs flying through challenging environments, the following sensors have been integrated on the drone: (i) the DVS240 event-based camera [1]; (ii) a 6-axes IMU, integrated with the DVS240 camera; and (iii) the Infineon XENSIV 24GHz Position2Go radar sensor. Integrated to the Bebop 2 drone, a full HD RGB camera is mounted at the front and provides wide-angle video recordings on flight. The hardware architecture is detailed in Table 1 and Fig 1. The DVS2401 is an event-based camera with a frame resolution of 240 \u00d7 180 pixels. It outputs a stream of events characterized by bandwidth of 12 \u00b7 106 events per second, a high dynamic range of 120 dB, and an extremely low latency (12 us). Its low power consumption (180 mA at 5 V DC) makes it suitable for embedded applications. However, the form factor of the sensor limits the use in MAVs. For that reason, the protecting case of the sensor was removed, and the lens was replaced by a miniature lens, mounted on a custom-made, 3d-printed mount designed for the camera, thus resulting in a drop of the total weight by 75%, at 35 g" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001341_8600701_08667030.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001341_8600701_08667030.pdf-Figure2-1.png", + "caption": "FIGURE 2. The schematic diagram of the variable magnification ratio transmission structure of the hip joint and knee joint.", + "texts": [ + " In contrast to the transmission structure of the linear telescopic cylinder, the screw-crank-slider units ensure that the inertia center remains on the stroke plane of the screw when the active DOF joints move, accompanied by minor adjustments in a smaller range. The proposed arrange- 37622 VOLUME 7, 2019 ment reduces the calculation of the dynamic center position of the connecting rod inertia and the approximation error caused by the simplified estimation when the dynamic model is established. Furthermore, the hip joint and knee joint can flexiblymovewithin the range of\u221230\u25e6 to 100\u25e6 and 0\u25e6 to 120\u25e6 at large output torquewhenwearer works under the assistance of exoskeleton as shown in TABLE 1. As shown in Fig. 2, the motors of hip joint and knee joint are arranged in the opposite directions. In Fig. 2, lk1, lk2, lk3, lk4, Lk and lh1, lh2, lh3, lh4, Lh are distance parameters between hanging points and the rotating joints on the connecting rods. xk, xh are the available travel range of sliders. \u03b1, \u03b2 are the joint angles of active knee and hip joints, and \u03c6, \u03d5, \u03b3 , \u03b4 are parametric angle variables. The size parameters of the connecting rod directly determine the magnification ratio of the transmission structure and the joint rotation ranges. Therefore, the actual demanded driving torque at all target positions during motion gaits should be satisfied on the basis of ensuring a lightweight, simplified transmission structure" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001895_9312710_09495824.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001895_9312710_09495824.pdf-Figure3-1.png", + "caption": "FIGURE 3. Forces of two screw wheels rotating in opposite directions (Fn: normal force, Fv : vertical force, Fh: horizontal force. The relation equation between them is as follows: Fv = F n \u00d7 cos\u03b8 , Fh = Fn \u00d7 sin\u03b8 (\u03b8 is from Fig.2)).", + "texts": [ + " For convenience, the screw wheels can be easily attached and detached in the experiment. B. DRIVING PRINCIPLES OF SCREW-BASED CRAWLING ROBOT As the screw wheel rotates, the force between the granular particles on the ground and screw wheel\u2019s blade is shown in Fig. 2. There are two forces between the particle and blade: normal force and tangent force. The normal force is the dominant one [2], [4]. The robot moves forward with a pair of screw wheels rotating in opposite directions. The forces between the two screw wheels are illustrated in Fig. 3. The robot\u2019s forward force Fv and the horizontal force Fh come from the dominant force, Fn. The horizontal forces eliminate each other, leaving only the forward forces, which helps them move forward [2], [4]. Using this principle, the robot can move forward, backward, or left/right, depending on the direction of the screw wheels\u2019 rotation. III. EXPERIMENTAL SETUP A L9(34) orthogonal array based on four parameters- and two user conditions was designed for using the Taguchi method [21]\u2013[23]. These robust design parameters are based on the experimental results and corresponding S/N ratios" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004397_9437987_09345796.pdf-Figure10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004397_9437987_09345796.pdf-Figure10-1.png", + "caption": "Fig. 10. During the learning process for a vertical reaching task, when there is no load held in the hand, the wrist direction is straight (left two hands). When 1 kg load is held in the hand, the wrist bends in the direction of gravity (right two hands) to minimize the energy consumption.", + "texts": [ + " The R2 accuracy varies based on the number of joint synergies and as the number of synergy components increases, the elevation of accuracy of reconstruction can be observed. It is worth noting that the synergy level of the curves generally rises towards the end of the training both in DRL and PDRL, as fewer synergy components are required to reach higher R2 accuracy. This phenomenon is illustrated by the orange arrows as an example. It indicates that the motion becomes more synergetic in the learning course. Finally, the simulation represents good correspondence with the bio-mechanical experimental results reported in [45]. As depicted in Fig. 10, during the learning process, we observed that when there is no load in the hand, the wrist can be straightened without flexion (left two arms). However, when the hand holds certain weight load, the wrist starts bending in the direction of gravity (right two arms), to minimize the energy consumption. This is because when the hand is in horizontal orientation with the straight wrist direction, the external moment caused by gravity is maximal, as the gravity vector acts perpendicular to the long axis of the hand in this orientation" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.11-1.png", + "caption": "Figure 4.11 Collapsed View of Lifting Fork Assembly", + "texts": [ + "1 Collapsed View of Scissor Lift Assembly (P53) Figure 4.2 Exploded View of Scissor Lift Assembly (P54) Figure 4.3 Overview & Dimension of the Base (P55) Figure 4.4 Overview & Dimension of the Top (P56) Figure 4.5 Overview & Dimension of the Frame 1 (P57) Figure 4.6 Overview & Dimension of the Frame 2 (P58) Figure 4.7 Overview & Dimension of the Wheel (P58) Figure 4.8 Scissor Lift Supporting Operator Cabin (P59) Figure 4.9 Hydraulic Pump (P59) Figure 4.10 Front View of Scissor Lift with Maximum Lifting Range (P60) Figure 4.11 Collapsed View of Lifting Fork Assembly (P61) Figure 4.12 Exploded View of lifting Fork Assembly (P62) Figure 4.13 Overview & Dimension of Fork Lid (P63) Figure 4.14 Overview & Dimension of Fork Support Frame (P64) Figure 4.15 Overview & Dimension of Rack Axle (P65) Figure 4.16 Overview & Dimension of Rack Fixer (P65) Figure 4.17 Overview & Dimension of the Fork (P66) Figure 4.18 Overview & Dimension of Spur Gear (P67) Figure 4.19 Overview & Dimension of Rack Motor (P67) Figure 4.20 Fork Horizontal Movement of the Forks (P68) Figure 4", + " Since this is the scissor lift maximum position, 1.26m is the maximum loading. Figure 4.10 Front View of Scissor Lift with Maximum Lifting Range (m) The lifting fork is one of the most important parts of the forklift. Its job is to grab the load from shelves and move it up and down during the loading process. It is placed in front of the whole truck and connected to the operator cabin. First we will introduce the subassembly and its components. Then we will demonstrate how lifting fork work by demonstrating its three basic movements. Figure 4.11 is the collapsed view of the lifting fork assembly used in our forklift design. As the feature tree listed on the left shows, the assembly consists of 10 parts. There are two forks installed in front of the support frame and the support frame is attached to the fork lid thought a pillar which is rotatable to provide the lifting fork system with a rotation movement. There are two axles connecting the fork support frame with its two motors and rack fixer. One motor lifts the fork lid and the other one (rack motor) moves the whole system horizontally" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003119_f_version_1653545766-Figure22-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003119_f_version_1653545766-Figure22-1.png", + "caption": "Figure 22. Path planning for the CRS CataLyst-5 robot. (a) Robot arm simulation. (b) Configuration of the CRS CataLyst-5 robot arm.", + "texts": [ + " The method so far only works with planar robot arms; thus, the movement of the CRS-CataLyst-5 robot was limited to two axes. To carry out the implementation, the test was divided into two stages: 1. First, the workspace to be solved was established. A three-link robot arm with normalized dimensions regarding the CRS CataLyst-5 robot was used. The circular obstacles had a tolerance radius rt, which guaranteed no collision of the robot arm with the obstacle (foam balls). For this case, two goals (goal1 and goal2) were set and are depicted in Figure 22 by the line formed by gray boxes and the blue line formed by asterisks, respectively. The movements of the robot arm are semi-transparent. The robot arm first reaches Goal 1 (the first homotopic path has been followed). Then, the endpoint of this path is used as the starting position to obtain the second homotopic path and reach Goal 2. In this way, a single path is obtained capable of avoiding obstacles and meeting both goals. The computation time and memory consumption were 2 milliseconds and 0.924 KB, respectively. The sequence of movements is executed by the robotic arm, as shown in Figure 22a. 2. The second stage of this process is to adjust the numeric homotopy path data to the correct instructions for the CRS CataLyst-5 arm to follow the path. The CRSCataLyst-5 robot has five degrees of freedom, a teach pendant, and a controller for interpreting and processing the instructions sent by the computer through its Robcomm3 software to generate the movements of the robot [46,47]. Figure 22b depicts the robotic arm workspace. From Figure 23 (implementation), the sequence of movements of Figure 22a (simulation) is corroborated. In this work, a novel method for collision-free path planning for robotic arms using homotopy continuation methods was presented. This proposal is flexible since it is capable of working in the simulation with different characteristics of the robotic arm, such as different link lengths, an arbitrary number of links, or adding grippers. Moreover, the homotopy path-planning method for planar robotic arms (HPPM-PRA) can work with circular and ellipsoidal obstacles. Obstacle avoidance is achieved by strategically adding mathematical singular points to the links" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.53-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.53-1.png", + "caption": "Figure 5.53: Detailed view of corner fasteners", + "texts": [], + "surrounding_texts": [ + "5.11. Refinement and finalization of concepts 81", + "Refinement of concept 3:1, which can be viewed below in figures 5.52, 5.53 and 5.54. The footprint of the L-profiles has been enlarged and walls thickened. The supports have been slimmed down for a better fit in tight spots and the function of the corner fasteners has been tweaked for better visualization.", + "5.11. Refinement and finalization of concepts 83" + ] + }, + { + "image_filename": "designv7_3_0004536_lator-Oloworaran.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004536_lator-Oloworaran.pdf-Figure6-1.png", + "caption": "Figure 6: The modified DH parameters [15]", + "texts": [], + "surrounding_texts": [ + "Table 1: Figure 21 corresponding DH table taken from the simulation (bottom). ................................ 27 Table 2 : Corresponding DH table taken from the simulation for figure 20. ........................................ 28 Table 3: Joint to Joint distances and scale factors in the simulated robot ............................................. 33 Table 4: Maximum and average errors for the single movement test ................................................... 35 Table 5: Table on of repeatability results .............................................................................................. 36 Table 6: Results of running IK on the modelled physical robot ........................................................... 36 Table 7: Results of running IK on the 3-link, 8-dof robot .................................................................... 37 Abbreviations DH \u2013 Denavit-Hartenberg IK \u2013 Inverse Kinematics ODE \u2013 Open Dynamics Engine OLP \u2013 Offline Programming DOF - Degree of Freedom GUI \u2013 Graphical User Interface 1 Introduction 1.1 Articulate Robots No matter where we look in modern society, the influence of robots is ubiquitous. From basic robots who perform the same repeated action, such as a welding robot created by FANUC [1], to robots able to perform complex human-like activities such as cooking [2]. Ever since the creation of the first industrial robot, the Unimate, in 1961 to perform welding on car bodies for the General Motors assembly Line, robots have increasingly begun to take part in all aspect of modern life. Based on the International Federation of Robotics and the ISO (International Organisation for Standardisation) standard the definition of a robot is an automatically controlled, reprogrammable multipurpose manipulator programmable in three or more axes [3]. In particular, one class of robot are articulate or industrial robots which contain rotary joints [3]. In general, these robots contain a number of either rotary or prismatic (changing in length) joints plus an end effector. The end effector will sit at the last joint on the robot and its\u2019 position depends on the orientation of every joint preceding it. To manipulate the external environment, the end effector will consist of some kind of tool such as a screwdriver attachment or a gripper for grasping objects. Between robots joints are robot links, which connect joints together. In practice, articulate robots tend to be robotic arms with six degrees of freedom (six joints). 1.2 Robot Simulation Simulation is the process of modelling a virtual counterpart to a real object or system and replicating its function in a virtual environment for analysing the output or results. The model aims to mimic reality as closely as possible and allows for one to gather data on a physical system without access to the real system, or for a real system to exist. The very first robot simulations were introduced in the 1990s and included software such as RRS [4]. These were targeted towards industrial working robots [4] (the first type of widely used robot [5]) and were desired mainly by automotive companies and line builders [4]. At the time, robot cycle time (time to complete one loop of operation) and robot movement paths frequently deviated from actuality, leading to rework on real systems. Today, robot simulation is much more accurate and applies to a litany of different robots types like mobile and space robots [6]. Companies world-wide and academic researchers work on creating and enhancing them. One of the early main robot simulation systems was Stage [7] a free, 2D robot simulation system that could model mobile robots and sensors. From there, robot simulations have continued to grow in complexity, added various types of robots such as aerial, swimming and humanoid, and size, adding multi robot systems. Many of the largest robot simulators today allow for complex offline programming. Offline programming (OLP) is the ability to program a robot on an external PC and have that program be uploaded to the robot at a later time [6]. Though problems still persist, including the programming and modelling of realistic random errors (relating to motor control, senor accuracy, time delays), system programming [8], accurate modelling of physics for the environment and robots [8] and accuracy of the simulator compared to reality. 1.3 Aim 1.3.1 Motivation At present, subjects like engineering, computer science/programming and robotics are being integrated into early stages of learning within the Australian curriculum. Simplified robotics allows for students as young as pre-primary to learn how to decompose a complex task into a set of steps [9]. While the curriculum uses the word \u201cprogramming\u201d, in early years this refers less to learning to code and more so the use of computers to solve a simple task [10]. Current robotic simulation packages mainly focus on use in commercial/research environments, with many aimed towards upper high school and university level users who may have had one or two years of education in the field. Meanwhile, existing education aimed robot simulation systems tend to be either very basic systems, without modelling of articulate robots, or inaccurate representations of robot theory and many have a significant cost. These include packages such as LEGO MINDSTORMS robots and the virtual robotics toolkit or the root coding robot and iRobot Coding. It is not feasible for all institutions to acquire the equipment, personnel, or funds to use high class physical robots. As such, a free simulation system which may realistically mimic robots is needed which is low complexity. 1.3.2 Intended Contribution Thus, this paper proposes a standalone articulate robot simulation system with an additional interface to a real small robot manipulator. This software package seeks to provide a free, small, and selfcontained simulation system available for multiple platforms which is more suitable for educational purposes or informal small robot development. The system provides a convenient and easy to use experience, simulating robots which can easily be manipulated both with high-level programming and through the use of the graphical user interface. Furthermore, the simulation also implements an interface to operate a real small robot manipulator to demonstrate the use of robot simulation for physical robots. 2 Literature Review 2.1 Denavit-Hartenberg Parameters A kinematic chain, which may model a robot manipulator (or articulate robot), is composed of a set of robot links connected together by various joints. The figure below depicts 2 links in a generic chain, where \ud835\udc56 represents the link number (with 0 being the very first joint in the chain). It is evident that the position and orientation (pose) of a joint \ud835\udc56 directly depends on, and builds off of, the pose of the previous joint \ud835\udc56 \u2212 1. A compact way to represent this is through assigning each joint its own frame of reference and storing information on the difference between one joint\u2019s frame of reference and the next joint\u2019s. Though other approaches exist to modelling kinematic chains, Denavit-Hartenberg is the most widely exercised in literature and academia [13]. The Denavit-Hartenberg (DH) parameters were developed in 1955 by Jacques Denavit and Richard Hartenberg as a way of assigning coordinate frames to joints [14]. Each joint will have a set of the four DH parameters, and this will define the reference frames for that joint. Using these parameters, one may full specify the relative pose of a joint. Classic DH parameters will not be explored in lieu of modified DH parameters which have a slightly different (more consistent) method of assigning coordinate frames. The four parameters are: \u2022 The hinge angle, \u03b8, the angle between this joint\u2019s X-axis and the last joint\u2019s X-axis \u2022 The link length, a, length of the common normal between this joint\u2019s Z-axis and the last joint\u2019s Z-axis \u2022 The link offset, d, offset of this joint compared to the last, along this joint\u2019s Z-axis \u2022 The link twist, \u03b1, angle between this joint\u2019s Z-axis and the last joint\u2019s Z-axis By applying a series of transforms, forward kinematics can be achieved, the act of finding the endeffector (final joint) position from the reference frames of every joint in the chain. The formula for finding the transformation matrix to move a joint to its proper pose based on DH parameters is given below: (2.1.1.1) [15] (where n is equal to the joint number, or \ud835\udc56 previously) Or in matrix form: (2.1.1.2)[15] While the DH parameters are wide-spread and generally accepted, other reference frame assignment methods do exist. The DH parameters are considered here as they are the most well established and one of the simplest to comprehend but it should be noted other methods, such as screw based methods, may out-perform it in various aspects such as inverse kinematics [13]. 2.2 Inverse Kinematics Inverse kinematics (IK) involves finding every joint pose (defined by DH parameters) needed to place an end effector in a desired position. The IK problem is much more complex and computationally expensive than the forward counterpart. In general, there are two groups of methods for solving IK, numerical and analytical. Numerical methods often involve some form of iteration, where the endeffector and joints are transformed in steps and tend towards the target position. Conversely, analytical (or closed form) methods deal with devising solutions based on a specific robot\u2019s configuration (how the robot is physically defined) and forming a system of linear equations. Both methods have their drawbacks. Numerical methods are often much more computationally expensive than analytical methods and are prone to being caught in local maxima while tending towards a solution [16]. Analytical method solutions only exist for certain types of robot geometries [11] (where the DOF of the robot is lower than that of the gripper). As there are 6-DOF for general 3D movement, three for rotation, three for translation, many robots are made to be 6-DOF. Due to this, there is no general analytical method as they cannot be applied to all types of articulate robots. In contrast, numerical algorithms can be generalized to accommodate additional constraints and objective functions, compared to analytical solutions which are restricted to 6-DOF systems [16]. Hence, analytical methods are not considered (note many robot manufacturers design robots to conform to the geometry requirements and hence have their own standard equations for IK). One numerical method for solving the IK problem is through the use of the Jacobian transpose. The use of this matrix has been used in literature relate the force on an end effector to the torque on a joint [18] [19] [20]. Mathematically, the Jacobian inverse is used to solve the IK problem, but this incurs a high computational expense. Instead, the Jacobian transpose is much easier to calculate and serves as a good enough approximation [20]. Instead of considering a force-torque implementation of the IK problem, a more appropriate approach for this paper involves variables more closely aligned with the DH parameters. Hence, Luis Bermudez\u2019s IK method for the Unity game engine [21] which instead considers end-effector position and joint rotations is adapted instead. Let us define T as the pose vector denoting the final orientation of each joint when the end-effector is in the desired position and O as the vector defining the initial orientation of each joint. Then: \ud835\udc47 = \ud835\udc42 + \ud835\udc51\ud835\udc42 (2.1.2.1) Where dO is the change in O needed to reach the orientation solves the IK problem. While O is known, both T and dO are unknown. This equation will be used to iteratively move the robot end- effector to the desired position, in order to avoid huge oscillations, a multiplier is added to limit the change in orientation, h, where h may be a number manually tuned and generally less than 0.1. \ud835\udc47 = \ud835\udc42 + \ud835\udc51\ud835\udc42 \u2217 \u210e (2.1.2.2) The Jacobian, J, will be used to relate the spatial position of the end-effector to the angle of each joint. Where for a 3-DOF: (2.1.2.3)[21] Here, J relates the hinge angle of joints A, B and C to the position of the end-effector, p, in each axis, X, Y and Z. This can be calculated analytically as such: (2.1.2.4)[21] Where RA is the axis of rotation of joint A (in terms of DH parameters, \u03b8, is a rotation around this joints Z-axis) and likewise for RB and RC. E is the end-effector position and A, B, C are the joint positions as vectors. With the Jacobian acquired it can now be applied to finding dO. If V is the change in spatial position needed to move the end-effector to the desired point, then V is calculated as follows: \ud835\udc49 = \ud835\udc47 \u2212 \ud835\udc38 = \ud835\udc3d \u2217 \ud835\udc51\ud835\udc42 (2.1.2.5) As J*dO gives the difference in end effector position for the dO changes in orientation. Now: \ud835\udc49 = \ud835\udc47 \u2212 \ud835\udc38 = \ud835\udc3d \u2217 \ud835\udc51\ud835\udc42 (2.1.2.6) \ud835\udc3d\u22121 \u2217 \ud835\udc49 = \ud835\udc3d\u22121 \u2217 \ud835\udc3d \u2217 \ud835\udc51\ud835\udc42 (2.1.2.7) \ud835\udc3d\u22121\ud835\udc49 = \ud835\udc51\ud835\udc42 (2.1.2.8) And as noted before, the inverse can be approximated by the Jacobian transpose: \ud835\udc3d\ud835\udc47\ud835\udc49 = \ud835\udc51\ud835\udc42 (2.1.2.9) This will provide us with dO, which can then be applied to our robot manipulator and iteratively repeat this process until the end-effector is inside of a certain distance of our desired point. Problems with the Jacobian transpose method and the optimization-based approaches include the possibility of stops in local minima (minima is used here instead of maxima as the distance to the desired position is minimised). Numerical instability due to poor reliability near singularities of the Jacobian can prevent convergence towards a solution [16]. It is also liable to oscillation around the optimal solution if the step resolution (and hence the distance the end-effector moves each step) is too large. Often multiple optimisation methods are needed to make this method reliable. 2.3 Existing Simulators Below, currently available robot simulators are considered with their architecture and features, who provide similar functionality to the proposed system. For a more comprehensive list of simulation systems and their features (and comparison to the proposed system) see Appendix A. 2.3.1 Webots Originally developed in 2004 for Khepera robots [22], Webots is one of the major robot simulations used in research and industry at the moment and recently became free and open source. Webots can model any mobile robot included legged, wheeled and flying [22]. Containing accurate models for sensors and actuators, Webots has been successfully used in industrial applications to accurately model robots [23]. Webots is mainly programmed in C++ and Robots are programmed in C, C++/Java or third-party software such as MATLAB and these programs can be transferred directly onto real robots. The physics engine used is the Open Dynamics Engine (ODE) which allows for accurate simulation of collisions, friction and other forces between the rigid body (a solid body affected by physics but unable to be deformed) robots and the environment. Webots also uses its own 3D rendering engine (WREN) to show 3D environments and robots to the user. Multi-agent simulations and multiple different types of robots as well as customisable environments are all features. Creating and controlling a robot involves forming a chain of servo nodes which can be controlled from a user made controller program. This allows for custom programming of user defined robots. Making the system incredibly flexible. In addition to these features, Webots has toolboxes for complex computing such as artificial intelligence and computer vision [23] and allows users to write their own plugins. Similarly, to other popular robot simulators, Webots is aimed towards professional programming of robots and academia. This makes it difficult for one without programming experience to pick up easily. In addition, while the package is free, user support or consulting has a fee. Though in terms of accuracy and flexibility, Webots is one of the top-of-the-line simulation systems. 2.3.2 RoboDK RoboDK is another large, popular robot simulation system, widely used in industry and academia. The biggest difference between RoboDK and Webots is RoboDK is a paid service and as such is much more geared towards industry. RoboDK allows for simulation of industrial robots and allows for programming of various robot controllers including ABB RAPID, Fanuc and Universal Robots [24]. Similarly, to Webots, RoboDK also allows for programming in C/C++, Java and many thirdparty languages (including manufacturer specific robot programming languages) and allows for userwritten plugins. The system was made in Python and uses OpenGL for 3D rendering and the Gravity Plugin for physics. Where it separates itself from Webots is through the ability to perform CAD to Motion functions, allowing for robot machining to be programmed [25]. Examples of RoboDK use involve by NASA to program collaborative robotic arms [26] and Pen State University for education and research [27]. Again, RoboDK is a large, flexible and accurate robot simulation system. With many of the same strengths as Webots and the same flaws. Though it has the added disadvantage of being a paid service. 2.3.3 RoboSim RoboSim is designed for a single pre-defined articulate robot arm that can be manipulated by a user [28]. Created in 1996 and programmed with java and C as both a Java applet and Java application [29] the program was made by Rainer Pollak (original version) and Johannes Sch\u00fctzner (Java version) [30]. RoboSim is the predecessor to the proposed system, forming the outline for what this system aimed to provide. The robot has 6-DOF and consists of 3 links connected by 2 joints to a gripper which may open and close. The system is very limited, it has no physics engine and is rendered as a java applet, collisions are avoided by giving hard-coded limits to robot angles. The system is able to save robot positions and load them, as well as loading of simple programs using its own defined programming language in .file files (see Appendix B for commands). As the robot is a fully defined 6- DOF robot, the system may use analytical inverse kinematics to move the robot to a specified position. Included was a physical counterpart to RoboSim which could be programmed with the same .file files. RoboSim is a very limited and older system for simulating articulate robots. Though the attractive parts, which were adapted to the proposed system, include its simple design and use of the GUI to control a robot in addition to a simplified programming language. Overall, the system was much too limited to be very useful for applications outside of programming its real counterpart. 3 Software Framework 3.1 Requirements In order to achieve a useful articulate robot simulation system that is low complexity, the system aimed to meet the following requirements: \u2022 Users should be able to load in and customise their own articulate robot and see it rendered \u2022 The user should control their robot through the use of a graphical user interface (GUI) and view the resulting transformations through forward kinematics \u2022 The system should include realistic physics and allow for collisions \u2022 The system should implement some form of IK \u2022 The system simulated robots should be able to mimic a real robot arm \u2022 The system shall be free and available on any major platform 3.2 Constraints Constraints included: \u2022 Cost for real robot parts \u2022 Choice of real robot design (detailed below) \u2022 Computing power, assuming the system should run on any common computer \u2022 Choice of system engine, as it has to be widely supported 3.3 Real Robot In order to prove the usefulness of the program, a physical robot was needed which could be modelled in the simulation system. A robot design which is not too complex yet adequately shows the capabilities of the system should be chosen and built. When deciding on the specific design to use, prioritise included: \u2022 Moderate price (under 200$) \u2022 Mechanically easy to construct \u2022 Made of readily sourced parts \u2022 At least two limbs and a gripper \u2022 Easily programmable After considering multiple alternatives the Robot Arm MK2 Plus designed by Jacky Le and found on Thingiverse was used which can be found online at https://www.thingiverse.com/thing:2520572 for free. The final design, specification and parts list of the robot are presented in section 4. 3.4 Resources Used 3.4.1 Unity Unity is a cross-platform game engine for the creation of 2D or 3D games as well as simulations and animation. Unity allows for a user to create and edit 3D object and environments and allows for scripting using C#. Unity projects are supported by a wide range of platforms including iOs, Andriod, Windows, MacOS, Linux and many more. Unity presents the rendered scene to the user when the game is launched and uses its own physics engine to deal with rigid body objects. 3.4.2 Blender Blender is a free open source 3D creation suite. It allows for modelling, rigging, animation, simulation, rendering and compositing of 3D meshes. While Unity was also capable of making custom objects though the object editor, it is not well optimised for creating complex meshes and has a much narrower range of accepted file types when importing non-Unity models. 3.4.3 3D Printer and Work Tools The 3D printer and work tools were needed in the construction of the physical arm. Tools used included screwdrivers, files and a soldering iron. 3.4.4 Non-Convex Mesh Collider The Non-Convex Mesh Collider is a Unity asset created by Productivity Boost software development [31]. The asset is available on the Unity asset store and allows a user to create concave collision meshes. Unity, natively, only allows for convex collision meshes, meaning any holes in models would be considered as part of their collision mesh. This posed an obvious problem for importing complex robot parts which may have to fit together and hence this Unity asset allows for accurate collision meshes for many varieties of complex objects. 3.5 Design Philosophy As the goal was creation of a simulator for users new to the field of robotics, the design philosophy reflected the need for simplicity and intuitiveness over technical complexity. First and foremost, the design was meant to be easy to use and understand. Users should be able to use the system with little to no knowledge of robot control theory. In accordance, the system is not designed for rigorous use or commercial applications. There was no requirement to be as accurate or expansive as leading robot simulators, but rather create a system which could display the process of simple robot manipulation. The second highest priority was creating a customisable system, one which was able to take in any valid user model and allow the user to manipulate it and whatever way it was configured. To that end the system was built with little hard limits on robot configuration and the system was made modularly as so it would easily be extensible. 3.6 Metrics Evaluating Success In order to measure the success of the application, its functionality is tested to ensure the system achieves its goal of creating a useful articulate robot simulation. Hence, the main metric for evaluating success will measure the difference between end-effector positions of the virtual and real counterparts when both are manipulated the same way. To achieve this, both the constructed physical arm and its model in the system have the ability to undergo the same basic commands which are sent from the user and change the robot\u2019s orientation. Each movement will be considered in isolation and joints will be tested to expose if there is any difference in the accuracy of different joint types. Measurements for repeatability of the simulation will be included to show if there is any accumulated error or constant error in end-effector position. As a subset of this, a modelled robot should be to scale and be able to complete the same poses as the physical robot without self-collisions. Therefore, the robot\u2019s scale must be tested to ensure it provides an accurate representation of the physical robot. Through these three measurements, a comprehensive metric for how closely the simulation mimics the robot arm will be calculated. Additionally, IK tests will be done to find the percentage of time the robot is able to reach its desired point. Or conversely, find its position and response to non-reachable points. Two different robots with 2 and 3 links are considered to see the difference in their performance. The robot will start the test from a \u201cuntangled\u201d position, meaning the robot will either be straight or close to straight, initially, and then use IK to attempt reach several random positions. The two robots should also be given different start and desired positions as it is impossible to give them the same starting pose (due to the differences in robot configuration) and that pose may influence how easily they reach the desired point. 4 Final Design 4.1.1 General The final system was created in the Unity game engine and completely coded in C#. The figure below shows the general way the user and the system interact. A user will be able to open the executable, from there they will have access to the system GUI. The user may load in robots from the GUI or send commands to the system. If a user loads a robot, they will need to provide both the models (.obj files) to all parts of the robot and a configuration file (text file) which details how that robot is arranged and joints are configured. These files are then loaded into the system and sent to the game engine which will then load them as objects into the scene. Once a robot has been loaded a user may manipulate a robot through the GUI, changing the DH parameters of hinge angle or link twist of the robot. These changes are relayed back to the game engine which will recalculate the pose of the robot and send the new pose to the scene for rendering. In this way, users will be able to manipulate the scene in real time. 4.1.2 Robot and Objects The robot itself will be composed of five different types of objects, each of a different class. A simple robotic arm, modelled in the simulator, makes up the figure below. Both RoboJoint and RoboJointFirst define behaviour for the robotic joints. The only difference between the two is RoboJointFirst is the first joint in the robot and hence has no previous joint it is positioned relative to. These joints will each contain their own set of DH parameters and will have access to the last joint\u2019s DH parameters. By implementing the equations seen in section 2.1.1, the system uses forward kinematics from the DH parameters to fully define the robot pose. Their model is specified by the user. Each limb object simply acts to place themselves between their start and end joints. As the joints will be positioned as far apart as their link length parameter dictates, links will automatically fill this distance. As joints translate and rotate, a link will follow the angle of its start joint and place itself in the middle of their start and end joints. A base object must be defined for all robots, this part anchors the robot to the ground and undergoes no transformations. As there is no need for transformations, this object does not have any DH parameters and is simply a visual formality to make the robot look accurate. To complete the robot, a pair of gripper hands should be defined (though can be configured to be excluded). These are programmed to place themselves at the last joint, directly under and in front of the joint. Hence, to form the gripper, the last joint model should be for the gripper. The gripper hands initialise as open, separated by the width of the joint. They can then be controlled to either close or open. As the gripper is two pronged, the gripper hands should have two models. In addition, the object class defines any static objects not connected to the robot. These objects are still physics enabled which allows for the robot to interact with them (through gripping or collisions). They are also able to be dragged around by the mouse so the user can manipulate them easily. Hence, a virtual robot fully specified by its DH parameters has been created. When initialised, robots will be configured according to the user\u2019s input file (explained in section 4.2). Here the example robot from the above figures with no rotations is considered to demonstrate its DH table. As seen above, the robot has no rotations in any axis and is facing along the X-axis. The DH parameters also have 0-valued \u03b8 (hinge angle) and \u03b1 (link twist) for each joint. Each link has the corresponding link length (note this defines the length of link connecting to that joint). In addition, joints 1 and 2 have d-values (link offsets) of 0.7 and -0.7 respectively. This causes their displacement along the Z-axis, as seen in Figure 21. For simplicity, this robot initially has all its joint reference frames aligned with the world coordinate system. As a joint is transformed, that frame of reference will transform as well, so a rotation about the hinge angle is always around that joint\u2019s Z-axis, not the world\u2019s Z-axis. Once the DH parameters describing orientation are changed, the user will see the robot change its pose accordingly. Thus, forward kinematics have been achieved as the end-effector (gripper) has been placed in the correct orientation and position based on the previous joints\u2019 DH parameters and the robot has been fully specified. 4.1.3 Physics Every object in the scene is defined as a rigid body, allowing them to experience forces and interact with Unity\u2019s physics engine without deformation. The main use of the physics engine is to detect collisions between two objects, but other forces also exist such as gravity. Objects can be collided with, including self-collisions for robots, and pushed. For the purpose of this simulation, many physics forces (such as friction) exist in the system but are either ignored or unhandled. This simplification is appropriate as the system is not intended for intense analytical use but rather as a demonstration or informal testing of custom robots." + ] + }, + { + "image_filename": "designv7_3_0000224_LobsterMechanics.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000224_LobsterMechanics.pdf-Figure2-1.png", + "caption": "FIGURE 2. Fabrication process: (a) Molding of the roof and bottom layer of the soft actuator with a three-part mold, (b) sealing two layers together and (c) assembling the soft actuator with rigid shell segments.", + "texts": [ + " Moreover, as the soft chamber will conform to the internal geometry of the rigid shells, it provides the flexibility in soft chamber design, where a much simpler geometry can be used. For example, a rectangular soft chamber is adopted in this work. Other simple cross-sections, i.e. circle, triangle, can be utilized as well. The resultant soft chamber exhibits a simplified design and fabrication process without sacrificing the overall performance of the actuator, as will be shown later in this paper. Fig. 2 presents the fabrication process for this hybrid actuator. The casing of the soft chamber was fabricated using a mixture of hyperelastic material including Ecoflex 00-30 and Dragon Skin 30 in a ratio of 6:4. The roof and bottom layers of the soft chamber were made with three molds, including an outer mold, a middle mold and a base mold (Fig. 2(a)). A thin layer of the same material was used to seal the top and bottom actuators together (Fig. 2(b)). The soft actuator was dipped into the same mixture to seal one end. A pneumatic tube was fitted to the open end of the soft chamber, and then sealed with silicone proxy. The 2 Copyright \u00a9 2017 ASME Downloaded From: http://proceedings.asmedigitalcollection.asme.org/ on 11/09/2017 Terms of Use: http://www.asme.org/about-asme/terms-of-use rigid shell was designed in Fusion 360 and then 3D printed with a Form 2 printer using Clear V2 (FLGPCL02) resin with 0.1mm layer thickness. Three types of shells were designed including the modular shell segment, an end cap to ensure a simple fixture and a distal tip segment for better force measurement at the tip. Finally, the soft chamber was inserted into the 3D printed shells to form the hybrid actuator (Fig. 2(c)). The contact surface between soft chamber bottom and each shell segment was glued to ensure a consistent stretch along the soft chamber under actuation. The hybrid actuator design can be tuned by changing several geometric parameters including internal width and length of the soft actuator, wall thickness, the distance between two axes, shell inner radius and the distance between the joint axis and soft actuator bottom (see Fig. 1). Geometric parameters chosen in this design was based on a further application in a robotic glove" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.22-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.22-1.png", + "caption": "Figure 4.22 Rotation of the Forks", + "texts": [ + "12 Exploded View of lifting Fork Assembly (P62) Figure 4.13 Overview & Dimension of Fork Lid (P63) Figure 4.14 Overview & Dimension of Fork Support Frame (P64) Figure 4.15 Overview & Dimension of Rack Axle (P65) Figure 4.16 Overview & Dimension of Rack Fixer (P65) Figure 4.17 Overview & Dimension of the Fork (P66) Figure 4.18 Overview & Dimension of Spur Gear (P67) Figure 4.19 Overview & Dimension of Rack Motor (P67) Figure 4.20 Fork Horizontal Movement of the Forks (P68) Figure 4.21 Vertical Movement of the Forks (P69) Figure 4.22 Rotation of the Forks (P69) Figure 4.23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4.25 Overview & Dimension of the Steering Wheel (P71) Figure 4.26 Overview & Dimension of Chassis (P72) Figure 4.27 Overview & Dimension of Counterweight (P73) Figure 4.28 Overview & Dimension of Mast 1 (P74) Figure 4.29 Overview & Dimension of Mast 2 (P75) Figure 4.30 Overview & Dimension of Tire (P76) Figure 4.31 Rendering Model of the Forklift (P77) Figure 4", + " The forks usually rest on one side of the truck (depending on which side of aisle the load is sitting and the fork will be on the other side waiting for the next move). In this case it is on the left side of the truck. After the forklift reaches the cargo, the forks will move forward in order to go under the cargo, as Figure 4.20b shows. The arrow indicates the forks move to the right of the truck. When those forks reach under the cargo, part of the fork assembly, including forks, the support frame and fork lid, will move up to lift the load up, see Figure 4.21. After the load is picked up, the forks will retreat to its middle position as shown in Figure 4.22a. At this point, the cargo has completely been moved away from the shelf and resting on those forks. Then the fork support frame makes a 90\u00b0 turn to make the cargo face in front as in Figure 4.22b. This is to make sure the whole center of gravity remains in the central line after adding the load and the truck keeps balance during the transportation. Then the forklift drives off the aisle and heads to its destination. After introducing two subassemblies (Scissor Lift and Lifting Fork), there are still some additional components. In this section, drawings and dimension of those parts are shown in Figure 4.23\u2013 Figure 4.31. Figure 4.27 is the counterweight of the forklift. It includes the battery and the motor that driving the whole truck" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001452_onf_er2017_02004.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001452_onf_er2017_02004.pdf-Figure1-1.png", + "caption": "Fig. 1. The kinematic model of robot Antares.", + "texts": [ + " In the paper [7] walking trajectory generation method, which includes free leg trajectory and ZMP methods, is considered. The method was tested on humanoid robot HRP-2. The test results show that balance was improved due to changing of ZMP at the expense of changing the foot position. The purpose of this paper is to analyze methods for ensuring the sustainable position and movement of humanoid robots in space. On the basis of the analysis, the most suitable method will be proposed for the subsequent use in the Russian anthropomorphic robot Antares (Fig. 1). \u00a9 The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). The robot Antares is unique in that it has two-motor knees, which provides larger angles of rotation to the engines, flexibility and plasticity of the leg assembly in comparison with analogues [8]. The two-motor knee greatly complicates the kinematic scheme, so it is necessary to carefully select the solutions ensuring the stability of the position of this robot [9]", + " In the work [10] for solving the problem of stabilization of a bipedal walking robot on the basis of its inertial properties, a two-link inverse pendulum model was used to represent the robot. The idea of controlling such a pendulum lies in the redistribution of the angular momentum of the translational motion into rotational motion and vice versa. This approach allows reducing the moment on the side of the support and to control the sign and magnitude of the moment of gravity. The authors of the article regard a two-link inverse pendulum (shown in Fig. 2) as the control object, the hinge axes of which are parallel and allow the pendulum to move in the vertical plane. In Figure 1, l1, l2 is the length of the rods; m1, m2 are the masses of rods 1 and 2, respectively. The mass of each rod is distributed evenly along the entire length. The control action is the angle of rotation of the rod 1 with respect to the vertical \u03b2. The authors of the article proposed a formula for the mathematical model of the research object: = ( , ) \u2212 ( , ) + \u0441\u0442 + sin ( ) ++ sin ( ) + + \u2212 ( \u2212 ) (1) where Ms is the moment from the side of the support surface; K is the angular momentum; \u0391, \u03b2 - angles of rotation; K\u0441\u0442\u03b1 is a constant coefficient of stabilization with respect to the angle \u03b1" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002299_le_download_5769_pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002299_le_download_5769_pdf-Figure2-1.png", + "caption": "Figure 2 Relationship between the quadruped robot base coordinate system and the world coordinate system", + "texts": [ + " Based on the D-H[28] method, considering the foot position of a quadruped robot in the world coordinate system, the world coordinate system is defined as E, the reference coordinate system of the quadruped robot body is B, and its origin is located at the centroid of the quadruped robot. The base coordinate system of the left front leg is 0LF, and the base coordinate system of the right front leg is 0RF; the base coordinate system of the left hind leg is 0LH, and the base coordinate system of the right hind leg is 0RH. The coordinate system diagram is shown in Figure 2, where m is half the length of the quadruped robot, and n is half the width of the quadruped robot. 3.2.1 Forward kinematics of the single leg According to the D-H method, the transformation nTn+1 (called An+1) between the coordinate system n and the coordinate system n+1 is the right multiplication of the 4 motion transformation matrices. 1 1 n n nT A 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 10 0 0 0 1 n n n n n n n n n n n n n n n n n C S C S S a C S C C C S a S S C d (1) where, C=cos, S=sin; n+1 represents the angle of rotation around the zn-axis; dn+1 represents the distance of translation along the zn-axis; an+1 represents the distance of translation along the xn-axis; n+1 represents the angle of rotating the zn-axis around the xn+1-axis", + " Gait planning is mainly divided into two parts, one is to determine the coordination relationship between the legs, that is to determine the duty ratio and phase difference, and the other is to plan a reasonable foot-end trajectory curve. The swing phase and stance phase of a quadruped robot were studied during a walking gait. In order to reduce the impact force when their feet touch the ground, a low contact compact foot trajectory planning method using high order polynomial curve is used to carry out the foot trajectory planning of robot for foot-end trajectory planning. Figure 2 shows that the quadruped robot walking direction was the X-direction, and the leg raising direction was the Z-direction. According to the requirements of the quadruped robot's foot-end movement, the displacement constraint equations of the quadruped robot's swing phase foot-end trajectory in the walking direction (X-direction) and leg raising direction (Z-direction) were shown as follows: 0 2 2 t t T S x S x (9) where, xt=0 represents the initial position; xt=T represents the end position; S is the gait length at the foot of the swing phase, cm; T is the period of the swing phase, s" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004467_1145_3242587.3242665-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004467_1145_3242587.3242665-Figure3-1.png", + "caption": "Figure 3. Schematic design of the prototyped backpack arms system.", + "texts": [ + " Our prototype consists of three basic components: a mobile backpack equipped with two robotic arms, feet tracking devices, and a control software. The backpack includes two robotic limbs (arm/hands manipulators), control boards, and a 12V battery. The purpose of making the system as a backpack is to maintain the relationship between body motion on the torso and the arms, so that both are in the same frame. Such design would help maintain consistent coordination and thus consistent operation. The total weight of the system is about 9 kg, and the dimensions excluding the robotic limbs are shown in Figure 3 . An external PC is used for controlling the system and calculating the coordination of the joints. The arms of this prototype are designed in human scale with 6 degrees of freedom (DoF) to perform free spatial manipu- lations. The end effectors of the arms are designed to accept different types of manipulators (e.g. hand, pointer, tool, etc.), thus allowing for modular design. Figure 3 provides the schematic design of the developed arms, along with the joint placements and the link dimensions. For driving the arms, servo motors (model Kondo Kagaku B3M-SC-1070-A and B3M-SC-1170-A) were used for the six joints on each arm. The first two joints (J1, J2) are driven using twin motors since these joints would require the highest torque. The rest of the joints (J3-J6) are driven by single motors. On the tip of the robotic arms, where hands would be on human arms, we can attach various manipulators (e" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003325_8478841_08373731.pdf-Figure12-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003325_8478841_08373731.pdf-Figure12-1.png", + "caption": "Fig. 12. Sketch of the SoftHand 2 human\u2013machine interface. It enables an user to easily experiment with the robotic hand. The main subsystems are highlighted in figure. The interface includes a battery, the only component not already included on-board on the hand.", + "texts": [ + " In the second row, \u03c3 = \u03c0 2 and s moves from 5\u03c0 2 to \u2212 5\u03c0 2 mm. This is the movement that characterize SoftHand 2 w.r.t. the previous version, and that is completely conveyed by friction effects. Note that the behavior is coherent with the design framework (see Section IV) and with the one obtained in simulation (see Section V-D). The SoftHand 2 can be controlled through a digital input by a computer. However, to realize a more natural control by a human operator, we designed a mechanical interface (see Fig. 12). The operator, holding the handle, can move a joystick (512 ADAFRUIT analog 2-axis joystick) using the thumb. Upward direction is translated into an increase of the \u03c3 command (i.e., first DOA), in an integral fashion. The downward direction corresponds to a decrease of \u03c3 instead. Left and right directions correspond to a similar change of s. Pressing the select button reset the hand to initial position. The handle also holds a battery pack in the lower part. Using the proposed interface, we were able to test the SoftHand 2 performances independently from automatic planning and control performances" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000967_f_version_1463729718-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000967_f_version_1463729718-Figure2-1.png", + "caption": "Figure 2. Sensors used in the experiment: a force platform AMTI OR6 (a) and an inertial sensor Xsens MTx comprising both accelerometer and gyroscope (b).", + "texts": [ + " Lower body markers are placed in the following positions: left and right back of the foot (heel), left and right outside of the ankle, left and right 2nd toe of the foot, left and right hip joint. For the upper body, they are placed on the bony prominence on top of both shoulders and one in the center of the upper torso. No arm and head motions are evaluated in this experiment. Kinematics information are recorded at a sampling rate of 100 Hz using an inertial sensor unit (Xsens Technologies B.V., Enschede, Netherlands) attached with an elastic strip on the trunk, including an accelerometer and a gyroscope (Figure 2b). Three markers are placed on the IMU external surface in order to compare data from the Vicon system and the inertial sensor. The task is performed on a standard force platform AMTI OR6 (Advanced Mechanical Technology Inc., Watertown, USA) synchronized with the Vicon system and data are recorded at a sampling rate of 1 kHz (Figure 2a). Each subject is asked to perform a bowing task without bending the knee in order to assume legs as a rigid link. Each participant experiment session consisted of four trials each composed of three bows. A general scheme of the experimental set-up is summarized in Figure 3. Inspired by state-of-the-art human stance modeling [15], the human body was modeled as a double-inverted-pendulum (DIP). A two DOF (NB = 2, d \u2208 R52) model of the human body for each subject was developed by using the Universal Robot Description Format (URDF) which is an XML-based file format for representing kinematics and dynamics of multibody systems" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure9-5-1.png", + "caption": "Figure 9-5. Geometry of Linkage of Independent Sprung Wheel", + "texts": [ + " In addition, changes in camber and/or track during vertical movement may be inherent for particular suspension arrangements. For the typical front wheel independent suspension shown in Figure 9-3, it is usually desirable to minimize the amount of lateral movement (scrub) of the tire at the ground when the wheel moves upward from its normal loaded position. For a system composed of parallel, unequal length wishbones, this can be accomplished by choosing the proper ratio for the lengths of the upper and lower eontrol links. Figure 9-5 is a diagram of the kinematics of the system under consideration (Ref. 8). For a vertical displacement d of the wheel, points 1 and 2 move to 1' and 2', respectively. For .small values of d, the lateral displacements of points 1 and 2 are approximately d2/2U and d2/2L. A simple geomet- 9-9 AMCP 706-356 ric construction reveals, for the conditions of no lateral movement of the tire at the ground, the ratio of: L h + S (9-1) Similar kinematic studies and additional kinetic investigations should be made for any proposed independent suspension layouts to incorporate the following desirable characteristics into, the system (a) minimum gyroscopic or inertia torques with vertical displacement, (b) minimum disturbance of the steering geometry with vertical displacement, and (c) favorable changes in whee' attitude, e" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000827_f_version_1624432525-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000827_f_version_1624432525-Figure9-1.png", + "caption": "Figure 9. Simulation of soft joint with a 60 N upward force applied on the free end.", + "texts": [ + " This prism represents the weight of the robot gripper in the simulation, Figure 8. In addition, a 10 Newtons downward force is applied to the end effector, simulating an external weight of 1 kg and causing a higher end torque. The simulation shows a deflection of 7.38\u25e6 and a maximum deformation of 0.75 MPa. Additionally, another stress study was carried out to check if the yield strength of Ninjaflex is not exceeded. It was noted that when applying 60 N force at the end of the soft joint, as shown in Figure 9, a bending angle of 60\u25e6 was reached and the maximum deformation was 2.9 MPa. Therefore, a no permanent deformation is confirmed when the soft link reaches an inclination angle of 60\u25e6. The position of the soft joint is defined as the combination of orientation and inclination, where inclination is the curvature angle of the joint, and orientation is the angle of the plane perpendicular to the base that contains that curvature. It achieves two DOF of flexion from the three tendons, thus the position depends on the distance of the tendons and their combination" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001476_nf_cscns20_02019.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001476_nf_cscns20_02019.pdf-Figure1-1.png", + "caption": "Fig. 1. Schematic diagram of the force sensor.", + "texts": [ + " However, in order to ensure the accuracy and reliability of the sensing system, a sensor is designed which includes the flexible joints with four FBGs and a sensing structure with a central FBG. The two ends of the flexible joint are designed with axial and radial connection and fixing mechanisms. The cross-sectional connected domain of the material is larger than the sum of the cross-sectional areas of the four elastic beams to ensure that the flexibility is concentrated at the flexible joints. The design purpose of the front cross beam mechanism of the flexible joint is to make the force transmitted from the robot wrist more concentratedly act on the four elastic beams. Fig. 1. Schematic diagram of the force sensor. The force of the surgical robot is transmitted to the center of the wrist through the end effector. Therefore, the force of the end of the surgical robot is equivalent to the center of the wrist in the actual modeling process. The designed force sensing system is equipped with wrist joints to reduce the cost of the experimental process, before proving the performance of the sensing system. The micro-end sensing structure equipped with 4 FBGs is shown in Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004845_e_download_7789_4821-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004845_e_download_7789_4821-Figure4-1.png", + "caption": "Fig. 4. Diagram of a manipulator with 5 degrees of freedom", + "texts": [], + "surrounding_texts": [ + "The direct kinematics allows to determine the final position and orientation of the manipulator's final effector, knowing the value of each joint and its geometric parameters. For this purpose, the use of Denavit-Hartenberg is proposed, which makes it possible to establish the relative transformations between links. Table 1 shows the Denavit-Hartenberg parameter matrix for the robot to be simulated. From this matrix, the transformation matrices are proposed that will allow to relate the coordinate systems from one degree of freedom to the next. Eq. (1), Eq. (2), Eq. (3), Eq. (4), Eq. (5) show transformation matrixes of the coordinate system 0 to 1,1 to 2,2 to 3,3 to 4 and 4 to 5. iJOE \u2012 Vol. 14, No. 2, 2018 93 !!\" ! !! ! !!!!!!!! ! !! ! ! !!!! ! ! ! ! ! !!!!!!!! !!!!!!!!!! !! ! (1) !!\" ! !! !!! ! !! ! !! !! !! ! !! ! !! ! ! ! ! !!!! !!!! !!!!!!!!!!!! !!!!!!!!!! (2) !!\" ! !! !!! ! !! ! !! !! !! ! !! ! !! ! ! ! ! !!!! !!!! !!!!!!!!!!!! !!!!!!!!!! (3) !!\" ! !!!! !!! !! !! ! !! !!!! !!!!! !! !! ! !! !! !!!! !!! !!! !!!! !!!! !!!!!!!!!!!! !!!!!!!!!! (4) !!\" ! !! !!! ! ! !! !! ! ! ! ! ! ! ! ! !! ! (5) From this, the pre-multiplication of these matrices is carried out, which makes it possible to find the transformation matrix !!\", which describes the system kinematics with respect to the reference coordinate system. From this matrix, vector ! is extracted since it contains the position of the final link of the manipulator in !!!!!. !!\" ! !!!! !!!! !!!! !!!! ! !\"# !\"#$ !\"#$% !!\"#$%$ (6)" + ] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.32-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.32-1.png", + "caption": "Figure 4.32 Collapsed View of Forklift", + "texts": [ + "22 Rotation of the Forks (P69) Figure 4.23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4.25 Overview & Dimension of the Steering Wheel (P71) Figure 4.26 Overview & Dimension of Chassis (P72) Figure 4.27 Overview & Dimension of Counterweight (P73) Figure 4.28 Overview & Dimension of Mast 1 (P74) Figure 4.29 Overview & Dimension of Mast 2 (P75) Figure 4.30 Overview & Dimension of Tire (P76) Figure 4.31 Rendering Model of the Forklift (P77) Figure 4.32 Collapsed View of Forklift (P78) Figure 4.33 Exploded View of Forklift (P79) Figure 5.1 Mass Property of Truck Body (P81) Figure 5.2 Mass Property of Counterweight (P82) Figure 5.3 Mass Property of Operator Cabin (P82) Figure 5.4 Mass Property of Supporting Mast (P83) Figure 5.5 Mass Property of Subassembly: Lifting Fork (P83) Figure 5.6 Mass Property of Subassembly: Scissor Lift (P84) Figure 5.7 Mass Property of Forklift Assembly (P84) Figure 5.8 Mass Safety Zone of Forklift (P85) Figure 5.9 Front View of Forklift\u2019s Center of Mass (P86) Figure 5", + " These two components assembled together would function as a support for the scissor lift and keep the movement of the lift only to vertical. Figure 4.30 is the front and back tires. The designs are the same; dimensions are the difference between these two tires. After introducing all the components and subassemblies in our forklift design, it is time to see the entire design. Figure 4.31 is the rendering model of the forklift truck collapsed view. This generates a more realistic image about how the forklift looks under its working condition. Figure 4.32 shows Figure 4.31 with the feature tree. As the feature tree shows on the left, there are 12 components (not including cargo) and two subassemblies. We have already introduced both subassemblies in previous section. The scissor lift pushes up the operator cabin alone with the lifting fork and the lifting fork in front of the truck is what the driver controls to pick up and drop all loads. Figure 4.33 is the exploded view if the forklift. It separates the forklift into 6 different major parts: the lifting fork in the front, the scissor lift, the operator cabin above it and the chassis under it, the supporting mast and the counterweight" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000283_0_msd_full_final.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000283_0_msd_full_final.pdf-Figure4-1.png", + "caption": "Fig. 4. (a) An overview of the Hand-Bot. (b) The magnetic grapnel with embedded MSD.", + "texts": [ + " Applications can be as anchor mechanism for robots from aerial to submarine, attaching systems for collaborative robots, brake systems or holding devices, gripper and manipulators, magnetic wheels, tool exchangers and precise positioning systems, magnetization systems or even a basic subpart for modular furniture among other ideas. Four different cases where MSD have been implemented and tested or are being used in robotics solutions are now described. 3.1. Magnetic grapnel for the Hand-Bot The Hand-Bot4 is an autonomous robot that aims at grasping objects and structures that you can see in Fig. 4(a). It will collaborate with other robots for locomotion in order to perform various tasks collaboratively. The robot embeds two manipulators that can grasp both objects or structures. It can throw a magnetic grapnel against a ferromagnetic roof. The anchor is linked to a mechanical cable, on which the robot can haul up and down. This anchor embeds a MSD and is energy autonomous thanks to supercapacitors. It has a motor to activate and deactivate the pin MSD. The robot communicates with the anchor with an infrared connection" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure6-21-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure6-21-1.png", + "caption": "Figure 6-21. Metalastic Whee/", + "texts": [ + " This may be a decided advantage in soils exhibiting very low bearing strength. In summary, it must be stated that this concept is novel and relatively untried. It is doubtful whether it can be applied successfully to large, 6-14 AMCP 706-356 B heavy vehicles, but it may prove useful for small, light-weight vehicles. 6-8 METALASTIC WHEELS Metalastic wheels is a term applied to a series of novel wheel concepts which utilize an elastic hoop for a rim and support it on a number of flexible spokes which spiral outward from a single central hub. Figure 6-21 shows one wheel of this type. The central disk serves a dual function: it limits the amount of vertical deflection of the rim, and it provides lateral stability. In operation, the metalastic wheel develops the long footprint of a track without a track's friction and weight penalties. It, too, like the spokeless, hubless, elastic wheel discussed in the preceding paragraph, maintains a constant unit ground pressure under varying loads, accelerations and tractive effort. Thus, it 6-15 AMCP 706-356 offers the load-carrying ability and dynamic stability of a wheel several times its diameter" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004966_0380310_10439149.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004966_0380310_10439149.pdf-Figure1-1.png", + "caption": "FIGURE 1. Operational environment and kinematics of dual crane cooperative system.", + "texts": [ + "NDEX TERMS Dual crane cooperative system, path planning, multiple rapid-exploring random tree. I. INTRODUCTION Mobile cranes play an essential role in the construction and civil engineering sectors, serving as indispensable machines for lifting and transporting heavy loads. In particular, dual crane lifting, where two cranes work together to lift and place a single workpiece as shown in Fig. 1, plays an important role in situations where single massive crane cannot be utilized for a variety of reasons including cost considerations, ground conditions insufficient to support the weight of a single large crane, and limited space issues that make access or maneuvering difficult [1], [2], [6], [11], [12]. The dual crane system The associate editor coordinating the review of this manuscript and approving it for publication was Hao Wang . also has the added benefit of reducing the yaw swing motion of the workpiece, since there are two anchor points at each end to hold the workpiece", + " PROBLEM FORMULATION In this section, the modeling of the dual crane system which serves as the foundation for automated path generation and collision detection is describe. Afterward, we will explain how to solve the hoist cables-object suspension problem that arises during the modeling process. Furthermore, it also explains the feasibility check process to verify whether the candidate configuration of the dual crane is a valid or not. A. DUAL CRANE SYSTEM MODELING In this study, it is assumed that the scenario of lifting girders on a pier or abutment for the construction of a bridge is the operational environment of a dual crane system as shown in Fig. 1. Each crane has 3 degrees of freedom, as illustrated in Fig. 1: the swing angle (\u03b8i), luffing angle (\u03d5i), and hoist length (lh,i). Basically, the length of the boom, lb,i is adjustable. However, once the workpiece is connected and the load is applied, the length of the boom remains fixed throughout the operation. The basic information given for automatic path planning is the initial configuration where the girder is connected to the crane, the final configuration at the girder\u2019s destination, the boom length, the operation range for each crane, and the location and size of obstacles within the worksite in the form of boxes" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004236_21z899h_fulltext.pdf-Figure4.2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004236_21z899h_fulltext.pdf-Figure4.2-1.png", + "caption": "Figure 4.2: Shows the reduced-order-model (ROM) considered to describe Aerobat\u2019s bounding flight. T , L, and D denote the thrust, lift, and drag forces that are not observable to the guard. Instead, they are added as an extended state (x3 in Eq. 4.16) to the guard dynamics and its estimated value used to control guard-Aerobat platform.", + "texts": [ + " The ESP32 boasts a dual-core Tensilica LX6 microprocessor with clock speeds of up to 240 MHz, along with integrated WiFi connectivity for transmitting data from OptiTrack. It also controls the six electronic speed controllers. To estimate the Guard\u2019s orientation, an IMU (ICM-20948) is used, complementing the OptiTrack position and orientation data. 23 Chapter 4 We conceptualize the dynamics between the guard and the Aerobat as interactions within a multi-agent framework. It is assumed that the guard remains unaware of the Aerobat\u2019s states. For control design, we employ a reduced-order model (ROM) of the guard-Aerobat platform, as depicted in Fig. 4.2. This ROM encompasses 14 degrees of freedom (DoFs): 6 DoFs representing the position and orientations of the guard (which are fully observable) and an additional 8 DoFs for the Aerobat. The latter includes 3 DoFs for position, 3 DoFs for orientations relative to the guard, and 2 DoFs for wing joint angles, accounting for the symmetry in the wings. This model is articulated using q, the vector representing configuration variables. Consider the guard\u2019s position pG, orientation (Euler angles) qG = [qx, qy, qz] \u22a4, body- frame angular velocity vector \u03c9G, mass mG, and inertia JG" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001786_f_ic4m2017_01004.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001786_f_ic4m2017_01004.pdf-Figure1-1.png", + "caption": "Figure 1. Schematic diagram of the robot.", + "texts": [ + " Yi Jun [10]et al develop dynamic simulation system of robot based on AutoCAD In this research, robot kinematics model by DH parameter method is improved, using Auto Lisp programming language to achieve six-degrees-of-freedom industrial robot workspace simulation. The influence of structure parameters on the shape and position of workspace and position is analyzed. This method also provides a powerful help for the design and research of industrial robot. According to the modified DH parameter, the six-degree-of-freedom robot link coordinate system is established. See Figure 1. a Corresponding author : zhangrui0908@bupt.edu.cn \u00a9 The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). The parameters of the robot D-H can be obtained as table 1: The position and attitude of the end of manipulator can be obtained through the robot coordinate system: 0 0 0 1 x x x x y y y y z z z z n o a p n o a p = n o a p T (1) Where: x x x y y y z z z n o a n o a n o a is the rotation matrix (attitude) of the robot end coordinate system with respect to base coordinate system; Formula (2) is the center of end position for robot" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004810_f_version_1402987349-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004810_f_version_1402987349-Figure6-1.png", + "caption": "Figure 6. A rotary joint controlled by a pair of l-ANLESes.", + "texts": [ + " ( ) / ( )a rT x EI l x ( )rl x L x x x ( ) ( ) / / ( )a rK x T x EI l x ( )x ( )aT x ( )aT x ( )K x ( )aT ( )K ( )aT ( )r x ( )aT l-ANLES exerts a force vector that is also a function of the torsion angle of the spring such as, (3) where, is the lead of the large lead ball screw (see Figure 1). is a unit vector along the rod axis of the l-ANLES, which depends on the joint angle . A pair of l-ANLESes exerts forces individually that counteractively affect a rotary joint axis as a torque as follows, (4) where is a unit vector of the rotary joint and and are moment arm vectors from the rotary axis to force vectors of l-ANLES, which are functions of the joint angle (see Figure 6). is a torque due to a whole gravitational effect and is a torque generated by contact with external objects. In Equation (4) is not considered because the aim is to develop a robotic joint in which stiffness can be set regardless of external forces or load torques on the joint. torques due to the l-ANLES. Denoting where and are torsion angles of the l-ANLESes provided by the individual motors and Assuming, ( ) 2 / ( ) ( )l d a lT F u d ( )l eu e ( ) ( ) ( ) ( ) (2 / ) ( ) ( ) ( ) ( ) ( ) ( ) e e mR e lR R mL e lL L g ext d e a R mR e lR e a L mL e lL e g ext T T T T T T T k r F r F k r u r u ek ( )mR er ( )mL er e gT extT extT ( ) ( ) ( / ) , ( ) ( ) ( / ) R L a R a R a R a L a L a LT T T T T T R L ,R R R L L L (5) an equilibrium state is produced as (6) where The stiffness of the rotary joint is defined as, [Nm/rad] (7) If we consider changing the joint stiffness under a constant joint angle , and become constants. Therefore, (8) Since we can expect to always have opposite signs in a counteractive configuration, as shown in Figure 6, we can calculate the absolute value of Se as, (9) where are positive constant values under a constant joint angle . Equation (9) suggests that the joint stiffness can be adjusted by setting and under holding Equation (6), and that the non-linearity of is indispensable for the joint stiffness to be varied, because if is linear with respect to , takes a constant value, which means the stiffness is also constant regardless of . and will be subject to gravitational effects as described above, which might narrow the adjustable range of stiffness" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001071_9559726_09246671.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001071_9559726_09246671.pdf-Figure7-1.png", + "caption": "Fig. 7. Finding the contact point by computing the intersection/closest point of the line r(\u03b1) with the machine tool (in this case grinding disk). All quantities are given in the robot base coordinate system.", + "texts": [ + " External forces and torques acting on the end-effector are related by the cross product with position vector r M = r \u00d7 F = \u2212S(F)r = \u2212 \u23a1 \u23a3 0 \u2212Fz Fy Fz 0 \u2212Fx \u2212Fy Fx 0 \u23a4 \u23a6 r (7) where r denotes the vector from the end-effector to the contact point. Keep in mind that all these quantities are given in the robot base coordinate system, matrix S(F) \u2208 R 3\u00d73 is skew-symmetric; hence, its rank is equal to 2 \u2200S(F) = 0. Consequently, there exist multiple solutions for r satisfying (7). The space of all possible solutions forms a line defined by the following equation (see Fig. 7): r(\u03b1) = \u2212S(F)+M + \u03b1v (8) where S(F)+ denotes the pseudoinverse of S(F), \u03b1 \u2208 R is an arbitrary scalar value, and v = F/\u2016F\u2016 \u2208 R 3 belongs to the null-space of \u2212S(F) (since \u2212S(F)v = (F/\u2016F\u2016) \u00d7 F = 0). To avoid the computation of the pseudoinverse of S(F), we can use an alternative formulation r(\u03b1) = (F \u00d7 M)/\u2016F\u20162 + \u03b1v. (9) The proof of equivalence of both formulations is given in Appendix A. Thus, the point of contact cannot be uniquely determined unless additional restrictions are imposed. Assuming that the geometry of the machine tool is known, e.g., disk, torus, or belt, we can restrict the solution to lie at the intersection of the line with the tool. The contact point can then be determined by solving the following optimization problem (see Fig. 7): arg min \u03b8 2,\u03b1 1 2 \u2016d(\u03b8 2, \u03b1)\u20162 (10) where d(\u03b8 2, \u03b1) = p2(\u03b8 2) \u2212 r(\u03b1) (11) is the difference function between an arbitrary point on the line r(\u03b1) and an arbitrary point p2(\u03b8 2) on the surface of the machine tool, which is modeled as a virtual mechanism with joints \u03b8 2. To solve the optimization problem (10), we need to calculate the Jacobian of the difference function d(\u03b8 2, \u03b1) Jd(\u03b8 2, \u03b1) = [ J2,p(\u03b8 2) \u2212v ] (12) where J2,p is the positional part of the Jacobian of the virtual mechanism. We can then apply Gauss\u2013Newton iteration to compute the optimal \u03b1\u2217 and joints \u03b8 \u2217 2 of the virtual mechanism[ \u03b8 2, j+1 \u03b1 j+1 ] = [ \u03b8 2, j \u03b1 j ] \u2212 J+ d (\u03b8 2, j , \u03b1 j )d(\u03b8 2, j , \u03b1 j )" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001083_SET-IJSRMS-09265.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001083_SET-IJSRMS-09265.pdf-Figure3-1.png", + "caption": "Figure 3. Starting Shape of Component", + "texts": [], + "surrounding_texts": [ + "The body structure other than Figure 2 is now selected as the \u2018Starting Shape\u2019. Optimizations are done on the basis of mass and volume which can withstand the given load input of 800 Newton\u2019s with the same strength. Yellow color denotes the starting shape and signifies the optimization of following shape in order to bear the given structural load." + ] + }, + { + "image_filename": "designv7_3_0003007_d-Sutherland-PhD.pdf-Figure3-16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003007_d-Sutherland-PhD.pdf-Figure3-16-1.png", + "caption": "Figure 3-16 System model showing some of the forces and torques acting on a robot\u2019s thigh and shin links.", + "texts": [ + " 90 There are a number of considerations that will influence the choice of angle when selecting an operating set point position for the balancing leg\u2019s knee joint: 3) Minimise supporting knee torque Minimising the knee torque required will result in reduced power consumption, and wear and tear on actuators. More importantly, a robot will always have a maximum output torque that can be supplied by the joint actuators. If this maximum torque is low, large supporting knee joint angles will not be possible. Knee torque output by the \u201csupport leg controller\u201d component needs to work against deviations between the measured knee position and the desired operating position. These deviations are the result of torques and forces acting on the shin and thigh joints of the robot leg. Figure 3-16 illustrates a simple robot leg, and some of the factors that result in the need for a corrective knee torque. 91 The system model diagrams in Figure 3-16 illustrate two possible configurations for the operating position of the supporting leg. The bent configuration (i.) works best for countering deviations driven by a clockwise HIP\u03c4 , while the straight legged configuration (ii.) minimises deviations driven by HIPf and GRf . The target robot\u2019s construction (especially weight), and the strength of its actuators will determine a suitable operating angle that minimises power requirements made on the knee joint. Usually, a straighter knee joint will be more efficient. 4) Implications of supporting knee angle for maintaining ground contact Although the Torso Driven Walking control system is designed to cope with loss of ground contact, the Torso Attitude Controller component will suspend application of a balancing torque for the duration time the supporting foot is above the ground surface. As a result, it is prudent to consider the implications of the supporting knee angle on ground contact. A glance at Figure 3-16 will show that if the torso were to rise for any reason, the robot is in danger of losing contact with the ground. In the first configuration, the ground contact will be maintained as the supporting leg extends with a rise in robot torso height. However when the leg is held straight, as in configuration (ii), any rise at all in the torso position will result in loss of contact with the ground. 92 3.2.7 Collision avoidance controller (CAC) The Collision Avoidance Controller is a \u201cvirtual model\u201d controller that works to prevent collisions between the robot links by maintaining an exclusion zone repelling links in danger of colliding" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002245_80058_FULLTEXT01.pdf-Figure3.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002245_80058_FULLTEXT01.pdf-Figure3.4-1.png", + "caption": "Figure 3.4: Boundary conditions for the simulation of tension.", + "texts": [ + " A quadratic 10x10 beam with a length of 100 mm is modelled and split into three separate parts. The middle section consists of one element in the axial direction and is assigned the properties of Table 1. The other two parts are assigned damage properties as well, but with slightly higher 26 stress limits to ensure that failure is initiated in the middle section. Both tension and compression are simulated for mesh sizes of 10, 5 and 2.5 mm. Boundary conditions for the simulation of tension can be seen in Figure 3.4. For compression, the displacement is oriented in the other direction. 27 3.2 Reference Test As part of their thesis project, the founders of Woodbe Engineering conducted experimental small-scale tests to determine the load-bearing capacity of the joints. The experimental setup included a floor element and two wall elements, connected using the BiteLock geometry. A hydraulic press applied a concentrated force using a cylinder in the middle of the floor elements in a deformation-controlled manner" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001576_(4)_2022_624-661.pdf-Figure10-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001576_(4)_2022_624-661.pdf-Figure10-1.png", + "caption": "Figure 10: A rather typical design of a hydroformed aerospace sheet metal part annotated with its features (a) as well as the content of its feature file (b).", + "texts": [ + " The position and profile information is quite low-level data, described in the class model represented in Figure 5, and therefore not included in the content of feature files, which are supposed to be user readable. We have selected three parts to represent the prototype\u2019s results. Each of these parts has a number of features, some of which highlight interesting points about the prototype\u2019s output and are therefore explained. In Figures 10, 11 and 12, each part is displayed annotated with its features and followed by its feature file content. To start with, Figure 10 (a) shows a rather typical design of a hydroformed ASM part that is annotated with its features. It has a lightening hole, attachment holes on the web, and an immediate flange deformed by a joggle with several attachment holes on the attachment flange and deformed flange. Figure 10 (b) shows the content of the part\u2019s feature file with \u201c~ ~ ~\u201d being used to avoid a long list of features having the same parameters. Figure 11 (a) shows another rather common design of a hydroformed ASM part that is annotated with its features. It has tooling and attachment holes on the web, and immediate flanges with several attachment holes on them. Due to the arrangement of the flanges, there are bend reliefs between them. The corners are not annotated in Figure 11 (a) for simplicity. Figure 11 (b) shows the content of the part\u2019s feature file with \u201c~ ~ ~\u201d being used to avoid a long list of features having the same parameters" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004645_f_version_1534755076-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004645_f_version_1534755076-Figure1-1.png", + "caption": "Figure 1. Two-link robot arm.", + "texts": [ + " This paper is organized as follows. First, in Section 2, a description of the planar two-link robot arm is provided, along with its dynamic model. Then, in Section 3, the control approach for controlling the robot from an initial configuration to the final configuration using an MPC approach is presented. A linear quadratic optimal control approach is developed and the comparative study is addressed in Section 4. Finally, simulation results are presented in Section 5. A planar two-link robot arm can be presented as depicted in Figure 1, where \u03b8i, Li, and Mi {i = 1, 2} are respectively the joint angle, the length, and the mass of the first link (i = 1) and the second link (i = 2). The gravitational acceleration is denoted by g. Machines 2018, 6, 37 3 of 14 Machines 2018, 6, x FOR PEER REVIEW 3 of 14 ( ) ( ) ( ) ( ) 1 1 2 1 2 1 1 2 1 2 sin sin cos cos x L L y L L = + + = + + . (1) Taking into account Equation (1), the total kinetic energy of the two-link robot arm is given by the following Equation (2): ( ) ( ) ( ) 2 2 2 2 2 1 2 1 1 2 2 1 2 2 1 2 2 2 2 2 2 2 2 1 2 1 2 1 2 1 1 2 2 1 cos 2 E M M L M L M L M L M L L = + + + + + + , (2) and the potential energy is given by the following Equation (3): ( ) ( ) ( )( ) 1 1 1 2 1 1 2 1 2 cos cos cos U M gL M g L L = + + + ", + " (4) With Lagrangian L, we can solve the Euler-Lagrange equation which relies on the partial derivative of kinetic and potential energies of mechanical systems to compute the equations of motion, defined as follows: ii d L L dt = \u2212 , (5) where L and T 1 2 = are respectively the Lagrangian of the motion and the torque vector. Developing Equation (5), the dynamic model of a robotic arm with two degrees of freedom (DOF) can be rewritten in the following form [24]: ( ) ( ) ( ),M C G Y + + = = , (6) where: \u2022 T 1 2 = is the vector of joint variables; \u2022 T 1 2 = is the vector of applied torques (control input); \u2022 Y is the output vector; \u2022 ( ) ( ) ( ) ( ) ( ) 1 2 1 1 2 2 1 2 2 2 1 2 sin sin sin M M gL M gL G M gL \u2212 + \u2212 + = \u2212 + is a vector of gravity torques; Figure 1. Two-link robot arm. The calculation of the dynamic model of this robot is based on the kinetic and potential energies. The tip of the second link is computed using the direct geometric model (DGM) as:{ x = L1 sin(\u03b81) + L2 sin(\u03b81 + \u03b82) y = L1 cos(\u03b81) + L2 cos(\u03b81 + \u03b82) . (1) Taking into account Equation (1), the total kinetic energy of the two-link robot arm is given by the following Equation (2): E = 1 2 (M1 + M2)L2 1 . \u03b8 2 1 + 1 2 M2L2 2 . \u03b8 2 1 + M2L2 2 . \u03b81 . \u03b82+ 1 2 M2L2 2 . \u03b8 2 2 + M2L1L2 ( " + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003439_f_version_1668760308-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003439_f_version_1668760308-Figure1-1.png", + "caption": "Figure 1. Structure layout of the mandrel ultra-precision machine tool.", + "texts": [ + " An in situ measurement system is integrated into the machine to distinguish the spindle radial error motion (SREM) and the workpiece\u2019s roundness error (WRE), which greatly eliminates random factors compared with online measurements. With the help of some existing STS experience in our research group, the compensation process did not require an extra and expensive FTS system, meaning that the machine could fully utilize the capabilities without the need for additional micro-motion systems. Finally, the machining of the workpieces with a roundness of fewer than 0.1 \u00b5m was realized and discussed. The mechanical structure layout of the mandrel ultra-precision machine tool has been presented in Figure 1. This ultra-precision machine tool adopts the XZC three-axis linkage scheme, in which the rotation of the spindle and X Z-slide are synchronized by an NC controller. The X and Z axes represent the linear motion perpendicular to and parallel to the major axis of the mandrel, respectively. The position of the X-slide is measured by a linear encoder with a 0.008 nm resolution. The maximum portable range of the X-slide is 250 mm. The spindle is equipped with a rotary encoder of 360,000 pulses/revolution for positioning" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001474_f_version_1551868188-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001474_f_version_1551868188-Figure4-1.png", + "caption": "Figure 4. The experimental robot.", + "texts": [ + " Finally, a SoftMax layer is used to output the classification results. As for the hyperparameters, we adopt the Spearmint Bayesian optimization library [59] to tune the hyperparameters in the artificial neural network, and grid search combined with 5-fold cross-validation to tune the hyperparameters in the feature-engineering approaches (e.g., SVM, ELM). To compare different classification methods applied in terrain classification, we conduct the experiment with a four-wheeled mobile robot on 8 different terrains. The experimental robot is shown in Figure 4. The robot is equipped with 4 dampers and 4 elastic tires, which constitute the robotic shock absorber. An IMU sensor is mounted on the robot roof to perceive the damped vibration. We collect vibration data by controlling the four-wheeled mobile robot to wander on eight terrain types which are different in rigidity, roughness, and flatness. Some of them are artificial terrains (e.g., asphalt, artificial grassland), while some are natural ones (e.g., cobble, natural grassland). In our experiment, we recover the vibration signal from the accelerometer readings by subtracting the gravitational acceleration, and then split the vibration signal into short segments" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003743_30457_FULLTEXT02.pdf-Figure4.13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003743_30457_FULLTEXT02.pdf-Figure4.13-1.png", + "caption": "Figure 4.13: The stiffest configuration in the global X direction", + "texts": [ + "9 portray the mapping of axial stiffness over the mechanical joint-space of joints 2 and 3 in the X, Y and Z principal axes respectively. Likewise, Figure 4.10, Figure 4.11, and Figure 4.12 present the 2D view of the same visualization with a color-bar for improved readability inside the thesis script. 62 | Static Analysis of The Manipulator 63 | Results & Discussion 64 | Static Analysis of The Manipulator As measured by the joint-space evaluation, the highest stiffness in the global X direction occurs when joints 2 and 3 are at 100 and -90 degrees respectively. This configuration is visualized in Figure 4.13. The stiffness in the global Y direction is shaped like a saddle, which conveys the meanings of minimizing the bending moment caused around the base of the robot by having the TCP close to the base. A configuration which is based around this idea is portrayed in Figure 4.14. 65 | Results & Discussion Figure 4.15 visualizes the robot in a stiff Z configuration according to Figure 4.12. The sensible conveyance of this result is to have the mass of the manipulator acting against the direction of the exerted force" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000185_f_version_1597717805-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000185_f_version_1597717805-Figure2-1.png", + "caption": "Figure 2. The aMussel robot\u2014sensors, actuators and communication devices.", + "texts": [ + " A detailed description of the functionalities and agent interactions featuring the aMussel and aPad robots (Figure 1), as well as the subCULTron system as a whole, is presented in [31]. Here, an overview is given to provide necessary context. 2.1.1. AMussel The aMussel agents serve as low cost underwater perception hubs, working together to establish a sensor network for distributed environmental monitoring and long-term data collection. As the primary measurement devices, they house a variety of sensors capable of monitoring relevant environmental factors. The design of the aMussel is represented in Figure 2. For the application described in this paper, the oxygen concentration, pressure, temperature, and turbidity sensors were installed, but any other compatible sensors can easily be added due to the robot\u2019s modular design. For long-range communication, aMussels rely on miniature acoustic modems called nanomodems while submerged, and have Bluetooth, GSM, and WiFi capabilities when on the surface. The aMussel was developed with long-term autonomy in mind, which is imperative for successful monitoring of environmental processes with slow dynamics" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002601_onf_pt2020_01007.pdf-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002601_onf_pt2020_01007.pdf-Figure11-1.png", + "caption": "Fig. 11. Flex spline combined stressed condition (detail).", + "texts": [], + "surrounding_texts": [ + "If the flexible spline has the desired elliptical shape through radial prestressing, then it is able to transfer torque. Power is transmitted through the engaged involved which as was already mentioned the teeth involved in one side of the crown are 7, so a total of 14. Once the flexible spline is engaged, then of the strain, the teeth themselves will be strained in addition to the pre-stressed main body. This stress consists in both bending and surface pressure. In the following figures 10 and 11 it appears that the final stress of the flex spline does not exceed the limit value for the PPS, which, as mentioned, in attraction reaches 150MPa." + ] + }, + { + "image_filename": "designv7_3_0000827_f_version_1624432525-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000827_f_version_1624432525-Figure8-1.png", + "caption": "Figure 8. Simulation of soft joint with a 500 g prism and a 10 N downward force at the free end.", + "texts": [ + " First, a no-load test was performed on the soft joint, by only simulating gravity and fixing one of the ends, as shown in Figure 7, with the red arrow representing the orientation of the gravity action in the simulation. One intended use of this soft joint is as a manipulator able to support different loads. Therefore, a second simulation was carried out with a rectangular prism with a fixed mass of 500 gr, homogeneously distributed. This prism represents the weight of the robot gripper in the simulation, Figure 8. In addition, a 10 Newtons downward force is applied to the end effector, simulating an external weight of 1 kg and causing a higher end torque. The simulation shows a deflection of 7.38\u25e6 and a maximum deformation of 0.75 MPa. Additionally, another stress study was carried out to check if the yield strength of Ninjaflex is not exceeded. It was noted that when applying 60 N force at the end of the soft joint, as shown in Figure 9, a bending angle of 60\u25e6 was reached and the maximum deformation was 2" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004534_f_version_1699696447-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004534_f_version_1699696447-Figure1-1.png", + "caption": "Figure 1. Mechanical design of CR. (a) Diagram of one segment; (b) the distribution of cable holes. Figure 1. Mechanical design of CR. (a) Diagram of one segment; (b) the distribution of cable holes.", + "texts": [ + " Section 3 presents the pre-grasping motion planning method based on an IAPF for the CR, following an introduction to the grasping workspace and the grasping area involved. Section 4 presents the results of the numerical simulations conducted to demonstrate the effectiveness of the proposed pre-grasping motion planning method. Section 5 concludes the paper. 2. Mechanism Design and Kinematic Modeling of the CR 2.1. Mechanism Design In this paper, a linkage cable-driven CR with rigid links is designed for ADR. The main structure of the CR consists of four identical segments connected in series, and the structure of each segment is illustrated in Figure 1. Each segment is composed of rigid links, Hooke joints, driving cables, and linkage cables. The Hooke joint allows adjacent rigid links to rotate about two axes. Each driving cable is wrapped with a driving cable tube, with one end fixed to the cable hole and the other end attached to the driving control box. The motion of the driving cables of each segment is decoupled by the tubes wrapping around the driving cables. Additionally, the synchronization of the joint motion within each segment is achieved by the linkage cables, which ensure that adjacent joints move at the same angle", + " Section 3 presents the pre-grasping motion planning method based on an IAPF for the CR, following an introduction to the grasping workspace and the grasping area involved. Section 4 presents the results of the numerical simulations conducted to demonstrate the effectiveness of the proposed pregrasping motion planning method. Section 5 concludes the paper. 2. Mechanism Design a d Kinematic Modeling of the CR 2.1. Mechanism Design In this paper, a linkage cable-driven CR with rigid links is designed for ADR. The main structure of the CR consists of four identical segments connected in series, and the structure of each segment is illustrated in Figure 1. Each segment is composed of rigid links, Hooke joint , driving cables, and linkage cables. The Hooke joint all ws adjacent rigid links to r tate about two axes. Each driving cable is wrapped with a rivi g cable tube, with one end fixed to the cable hole and the other end attached to the driving control box. The motion of the driving cables of each segment is decoupled by the tubes wrapping around the driving cables. Additionally, the synchronization of the joint motion within each segment is achieved by the linkage cables, which ensure that adjacent joints move at the same angle" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002095__emmft2023_03006.pdf-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002095__emmft2023_03006.pdf-Figure9-1.png", + "caption": "Fig. 9 General view of a small spacecraft: a) flight and prototypes of the small spacecraft \"Aist\" [35]; b) \"Aist-2D\" [36]", + "texts": [ + " Despite the fact that a single process is performed on a small technological spacecraft, it is necessary that its structural layout contains solar panels. Only in this way it is possible to achieve the generation of the required amount of electricity for the normal operation of the target and supporting equipment of a small spacecraft for technological purposes. For example, the technological equipment \"Growth Installation\" [28, 34] has a power consumption in the normal mode of about 165 W and a maximum of 235 W. While the flight and prototype small spacecraft \"Aist\" (Figure 9 a) without solar panels can provide only 15 W [35]. Equipped with solar panels, the small spacecraft Aist-2D (Figure 9 b) generates more than 285 W [36]. Thus, it can be stated that the requirements for the power-to-weight ratio determine the presence of large elastic elements in the form of solar panels in the design layout of the design of a small spacecraft for technological purposes. The requirements for the layout of the target equipment, including the microgravity platform, require the maximum use of all possible design methods to reduce microaccelerations. These methods are described in [2, 5, 34, 37] and can be reduced to the following recommendations: - optimal location of technological equipment inside a small spacecraft, for example, assuming its placement near the center of mass of a small spacecraft to reduce microaccelerations from rotational motion; - minimization of the number and size of large elastic elements, taking into account the requirements for power-to-weight ratio, which implies a decrease in the overall influence of the relative movement of the elastic part of a small spacecraft relative to its body; - optimization of the number and parameters of the executive bodies of the small spacecraft motion control system, involving the choice of its elements while simultaneously taking into account the requirements for the orientation of the small spacecraft and microaccelerations; - the use of damping devices in the attachment points of solar panels to the body of a small spacecraft, which implies a decrease in the influence of their own oscillations on the field of microaccelerations of the internal environment of a small spacecraft" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002392_f_version_1663666475-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002392_f_version_1663666475-Figure11-1.png", + "caption": "Figure 11. Mechanical and electronic configuration of the experimental platform (UR5 manipulator not shown): (a) front view, (b) back view, and (c) second control box.", + "texts": [ + " The Guidance module sends the linear and angular velocity inputs to move the Husky robot automatically inside the working environment. The conceived and designed layout has been implemented, and first navigation tests have been performed. The ground robot platform is mechanically designed to handle suitable sensors. Thus, the mechanical and electronic systems used for our experiments were prototyped and integrated on top of the main platform. The final configuration of the mobile robot for the first experimental tests is shown in Figure 11a,b. The second control box arrangement is reported in Figure 11c. The main ambient awareness sensors installed on the robot are a 3D LiDAR Velodyne VPL16 and an Intel Realsense D455 camera. The robot is equipped with a mini-ITX computer (see [36]), while the second control box embedded computer is a Jetson TX2 platform. The preliminary test targeted an emulated orchard and a safe navigation along a collision-free path given multiple goal points. For the initial evaluation of the implemented framework, a lab-emulated orchard was created in which parallel rows of tree were considered fixed obstacles on the map" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002768_sitava_Paper_016.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002768_sitava_Paper_016.pdf-Figure1-1.png", + "caption": "Fig. 1 Schematics of a CCR before and after actuation.", + "texts": [ + "in characterized by an elastic backbone which is actuated in various ways \u2013 pneumatic, shape-memory alloys, pre-curved beams and cables are some the wellknown ways. Cable-driven continuum robots (CCR) or tendon-driven continuum robots are widely studied for their simplicity in design and scalability and find use in fields such as medical devices, remote inspections, search and rescue, space applications, biomimetics etc. [1]. The CCR usually consists of a slender rod like structure forming the backbone and circular disks, with holes arranged in a circle, are attached at equal intervals along the backbone (see Fig. 1). Cables are routed through these holes and attached to the top-most disk, and when these cables are actuated from the bottom, the whole CCR bends and takes various shapes depending on the routing of the cable. Accurate modelling of CCR is essential in correctly predicting the shape and behaviour of a CCR. Detailed review of such models can be found in [2,3]. The simplest models employ geometry based methods that use the constant curvature approach [4]. More sophisticated models use finite element models [5, 6], elasticity based methods considering cable friction [7], Euler-Bernoulli beam theory [8], Cosserat rod theory [9,10], pseudo-rigid body model [11], EulerLagrange formulation [12], principle of virtual power [13] and geometry-based optimization method [14] to name a few", + " The ordinary differential equations and the boundary conditions form a boundary value problem. We compare the optimization and the Cosserat rod model for a CCR of length, L = 180 mm with 9 equal segments (10 disks). Each disk has 12 holes, equally spaced along a circle of radius, a = 8 mm. Out of the several numerical simulations, the results for four of them are presented in Table 1. \u2018Cable positions\u2019 denote the location of the cable in a particular disk according to the nomenclature in the inset of Fig 1, starting from the bottom to the tip of the CCR. For each case, the load applied was 400 grams and the corresponding change in length of the cable inside the CCR (found out experimentally) denoted as \u2018% Cable actuation\u2019 is presented in Table 1. All the simulations were performed using MATLAB in a PC with an Intel processor (3.1 GHz) and 16 GB RAM. Numerical simulation details: For the optimization-based method, equation 1 is solved using fmincon (available in MATLAB) with the in-built interior-point algorithm" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003807_icsbook-download.pdf-Figure20-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003807_icsbook-download.pdf-Figure20-1.png", + "caption": "Fig. 20: Input part (blank).", + "texts": [ + " 11: Example of robotic cell delivering value to a customer. 51 Fig. 12: Two cell deployment timelines (...) 56 Fig. 13: Overview of phases in the lean robotics cell deployment sequence. 59 Fig. 14: Design phase overview. 69 Fig. 15: Example of a simplified value stream map. 70 Fig. 16: Manual task map and layout steps shown in overall design phase sequence. 74 Fig. 17: Template for manual task map summary. 83 Fig. 18 : Example of a finished part. 86 Fig. 19: Parts are presented to the customer (the operator) in stacks on a table. 86 Fig. 20: Input part (blank). 87 Fig. 21: Blank parts are presented to the operator in stacks on a table. 88 Fig. 22: Sequence of manual process. 90 Fig. 23: Acme\u2019s manual task map summary. 93 Fig. 24: Acme\u2019s drawing of the manual cell layout. 94 Fig. 25: Acme\u2019s illustration of their manual station. 95 Fig. 26: Robotic cell concept, layout, and task map steps shown in overall design phase sequence. 98 Fig. 27: Robotic task map template. 105 Fig. 28: Acme\u2019s illustrated robotic cell concept. 107 Fig. 29: Acme\u2019s robotic cell concept layout", + "5 mm : Example of a finished part. Par t(s) presentation The following questions relate to how the parts are arranged at output (see Fig. 19). Are the parts singulated? How much space is around them? \u2192 The parts are stacked on top of each other. \u2192 The stacks of parts are on a tray. 87 Are the output parts placed onto a moving surface (e.g. a conveyor belt)? \u2192 No, they are placed on a stable surface (a tray on a table). Nature of the par t(s) How many types of parts are there? \u2192 There are four different types of blanks. \u2192 See Fig. 20. \u2192 Max: 110.5 mm x 63.75 mm x 19.2 mm rectangular blocks \u2192 Min: 70 mm x 50 mm x 19.2 mm rectangular blocks \u2192 Max. 0.36 kg Material: \u2192 Solid aluminum 88 Are there changeovers at this station? \u2192 Yes, two to three times per week. Are you planning to introduce new parts in the near future? \u2192 Perhaps in 9\u201312 months. There will be a similar kind of blank at input, and it will be within the min-max range defined above. Par t(s) presentation The following questions relate to how the parts are presented at input (see Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure8-1.png", + "caption": "Figure 8: Safety Factor in medium carbon steel", + "texts": [], + "surrounding_texts": [ + "Comparision of maximum contact stresses for the three materials of spur gear i.e. grey cast iron, high carbon steel and medium carbon steel obtained from Hertz equation and ANSYS 12.1 is given in Table 3. Table 2. Comparision of maximum contact stresses obtained from Hertz equation and ANSYS 12.1 Supr Gear \u03c3\ud835\udc4e (MPa) Hertz Equation \u03c3\ud835\udc4e (MPa) ANSYS 12.1 Difference (%) Grey Cast Iron 231.58 233.89 0.987 High Carbon Steel 95.785 94.19 1.6 Medium Carbon Steel 113.42 113.33 0.07 http: // www.ijesrt.com \u00a9 International Journal of Engineering Sciences & Research Technology [327]" + ] + }, + { + "image_filename": "designv7_3_0004673_ad.aspx_paperID_6671-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004673_ad.aspx_paperID_6671-Figure1-1.png", + "caption": "Figure 1. Architecture of three-link De-icing robot manipulator.", + "texts": [ + " System Description In general, the dynamic of an n-link robot manipulator may be expressed in the Lagrange following form: ,M q q C q q q G q N (1) where are the joint position, velocity and acceleration vectors, respectively, , , nq q q R n nM q R denotes the inertia matrix, , nxnC q q R 1nxN R expresses the matrix of centripetal and Coriolis forces, is the gravity vector, represents the vector of external disturbance , friction term 1nxG q R lt f q , and un-modeled dynamics, is the torque vectors exerting on joints. In this paper, a new three-link De-icing robot manipulator, as shown in Figure 1, is utilized to verify dynamic properties are given in section 4. 1mxR The control problem is to force ,n iq t R 1, 2,i m to track a given bounded reference input signal nRdiq t . Let be the tracking error vector as follows: ie t , 1, 2,i di ie q q i m (2) and the system tracking error vector is defined as Copyright \u00a9 2011 SciRes. ICA T. NGO ET AL. 243 1 2 1 1 1 2 1 1 2 0 0 0 0 0 0 0 0 0 , 1, 2, , i i i i i n ni i n i i i i ni i n i i ni k e k e k e k e k e k e i m (3) where n n niK R is the scaling factor matrix for the system tracking vector 1[ ]n n i i i ie e e e R , ", + " Finally, the optimal learning rate can be determined as follows: 22 1pi pi i ie k P i (33) where i Pi for , ,i ki kiP w m ki and , it can be obtained as: nik ,i wi ki ki ki P k a w 2 2 si kii mi ki ki ki ki ki d m P k a w m 2 3 2 si kii i ki ki ki ki ki d m P k a w 2 1 1 2 2 2 1 2 1 2 1 ki ni n si kii k ki ki ki si kni ki n n ni n d m P k a w d k e (34) 4. Simulation Results A three-link De-icing robot manipulator as shown in Figure 1 is utilized in this paper to verify the effectiveness of the proposed control scheme. The detailed system parameters of this robot manipulator are given as: link mass , lengths angular positions and displacement position 1 2 3, , ( )m m m kg , ( )q q rad 1 2,l l m , 1 2 3d m . The parameters for the equation of motion (1) can be represented as follow: 11 12 13 21 22 23 31 32 33 M M M M q M M M M M M 2 2 11 1 1 2 2 1 2 1 1 1 2 2 3 2 2 2 2 1 2 9 4 1 4 2 2M m l m c l l l l c s m c l l c l l 2 2 22 2 2 3 2 1 11 4 4 3 2M m l m l m l 23 32 3 2 2M M m c l 33 3M m 12 13 21 31 0M M M M 11 12 13 21 22 23 31 32 33 C C C C q C C C C C C 11 2 1 2 1 1 1 2 2 2 2 2 2 3 2 2 2 2 1 2 2 8 1 2 2 2 C m l l c s q m s c l m s c l s l l q 2 2 21 2 2 2 2 3 2 2 2 2 1 2 11 2 2 2C m s c l m s c l s l l q d q 22 3 2 2 3C m s l 23 3 2 2 22C m s l 32 3 2 2 2C m s l q 12 13 31 33 0C C C C 1 2 1 1 22 1 2 2 2 2 2 3 3 1 2 1 2 c c l c l m g G q s s l m c l m g m g (35) where 3q R and the shorthand notations 1 1 ,c qcos 2 2cos ,c q 1 sin 1s q and Copyright \u00a9 2011 SciRes" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002429_f_version_1460626905-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002429_f_version_1460626905-Figure1-1.png", + "caption": "Figure 1. GW physical structure. (a) Schematic diagram of a gyrowheel system; (b) Simplified gyrowheel structure diagram.", + "texts": [ + " In Section 3, the extended high gain observer (EHGO) is designed to implement the estimation of the related terms of the angular rates of the spacecraft, and the error convergence of the designed EHGO is proven in the time domain. In Section 4, the effects on the observer accuracy of the EHGO from measurement noise are further analyzed. In Section 5, for validating the performance of the proposed approach, the numerical simulation is performed. Finally, the conclusions are drawn in Section 6. Gyrowheel Physical Structure The GW system schematic diagram and simplified structure as shown in Figure 1 are similar to a dynamically-tuned gyroscope (DTG). As in the computer-aided design diagram shown in Figure 1a, the GW system mainly consists of the following subassemblies: case, motor, flexibility suspension structure, flywheel rotor, torquer consisting of the current coil and a permanent magnet and the tilt sensor. Among them, the case is fixed on the carrier, such as a spacecraft. The flexibility suspension structure is made up of a gimbal and inner and outer torsion springs, as shown in Figure 1b; the gimbal is connected to the motor shaft by a pair of inner torsion springs, and the rotor is connected to the gimbal by a pair of outer torsion springs. The rotor driven by the brushless DC motor rotates with a high time-varying speed. Thus, the torque along the spin direction of the rotor can be generated by adjusting the motor speed. Two pairs of torquers perpendicular to each other can provide two-dimensional tilt control torque to make the spin axis of the rotor tilt along the transverse directions. Additionally, the tilt sensors are designed to measure the tilt angles of the rotor with respect to the case. The special physical structure of the GW determines that the device not only can measure the two-dimensional angular rates of the spacecraft, like the DTG, but also can implement the three-dimensional torque output, like the variable speed double gimbal control moment gyroscope (VS-DGCMG). The simplified structure and the respective body frames of GW are shown in Figure 1b. The four body frames are case frame(F0:O-xcyczc), motor body frame (F1:O-xmymzm), gimbal body frame (F2:O-xgygzg) and rotor body frame (F3:O-xryrzr), respectively. And Figure 2 shows the angular position relationship of these four body frames. The rotation angles \u03b8x,\u03b8y,\u03b8z in Figures 1a and 2 are defined as chosen generalized coordinates for GW and can represent the motion about the three degrees of freedom of the GW system. They will be applied to derive the dynamical model of GW using Lagrange\u2019s equations and can be termed as spinning coordinates [2]. According to Figure 2, the direction cosine matrix of rotor with respect to the case can be given by: A = ( \u03b8y ) y(\u03b8x)x(\u03b8z)z = C\u03b8y C\u03b8z \u2212 S\u03b8x S\u03b8y S\u03b8z C\u03b8y S\u03b8z + S\u03b8x S\u03b8y C\u03b8z \u2212C\u03b8x S\u03b8y \u2212C\u03b8x S\u03b8z C\u03b8x C\u03b8z S\u03b8x S\u03b8y C\u03b8z + S\u03b8x C\u03b8y S\u03b8z S\u03b8y S\u03b8z \u2212 S\u03b8x C\u03b8y C\u03b8z C\u03b8x C\u03b8y (1) where (\u03b8i)i, i = x, y, z represent the rotation matrix of \u03b8i about the zm-axis,xg-axis and yg-axis, respectively, and S\u03b8i = sin \u03b8i, C\u03b8i = cos \u03b8i, i = x, y, z. Since the two-dimensional tilt sensors of the GW system in Figure 1a can measure the tilt angles of rotor with respect to the case, another set of case-referenced frames ( F \u20320,F \u20321,F \u20322,F \u20323 ) denoted by the orthogonal triads (x, y, z),(x\u2032, y\u2032, z\u2032),(x\u2032\u2032, y\u2032\u2032, z\u2032\u2032),(x\u2032\u2032\u2032, y\u2032\u2032\u2032, z\u2032\u2032\u2032) and case-reference coordinates( \u03c6x, \u03c6y, \u03c6z ) , respectively, need to be defined as shown in Figure 3. The frames F \u20320,F \u20323 are consistent with the frames F0,F3, and \u03c6x, \u03c6y can be measured directly by the tilt sensors in Figure 3. According to the rotation order of the case-referenced frames, the direction cosine matrix of rotor with respect to the case can be given by: A \u2032 = (\u03c6z)z ( \u03c6y ) y(\u03c6x)x = C\u03c6y C\u03c6z S\u03c6x S\u03c6y C\u03c6z + C\u03c6x S\u03c6z \u2212C\u03c6x S\u03c6y C\u03c6z + S\u03c6x S\u03c6z \u2212C\u03c6y S\u03c6z \u2212S\u03c6x S\u03c6y S\u03c6z + C\u03c6x C\u03c6z C\u03c6x S\u03c6y S\u03c6z + S\u03c6x C\u03c6z S\u03c6y \u2212S\u03c6x C\u03c6y C\u03c6x C\u03c6y (2) where (\u03c6i)i, i = x, y, z represent the rotation matrix of \u03c6i about the x-axis,y\u2032-axis and z\u2032\u2032-axis, respectively, and S\u03c6i = sin \u03c6i, C\u03c6i = cos \u03c6i, i = x, y, z" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001713_8948470_08986621.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001713_8948470_08986621.pdf-Figure2-1.png", + "caption": "FIGURE 2. Top view of IO-I.", + "texts": [ + " STRUCTURE DESIGN IO-I adopts the shape design methods of streamlined bodies of revolution, which is easy to process, low cost, a mature shell structure used in autonomous underwater vehicle, and can reduce fluid resistance and shell material. IO-I is an open-frame ARV with dimensions of 1.23m \u00d7 0.24m \u00d7 0.24m(length, width and height), weight 12kg, and a maximum underwater depth rating at 50m. The specifications of the vehicle are illustrated in Table 1, and the appearance of the submarine is shown in the figure 1. The layout of the enclosure is shown in the Fig2,3.The camera is arranged in the middle of the bow and hung on the beam of the bow with the hold hoop. In order to ensure sufficient lighting intensity during shooting, two LED lights are symmetrically arranged on both sides of the camera which located in the bow. A lifting ring is arranged at the top of the center of the submarine, and an electronic cabin is arranged on both sides of the lifting ring. Four magnetic coupling thrusters drived by 150V DC brushless direct current motor are selected" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure4.16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure4.16-1.png", + "caption": "Figure 4.16 Overview & Dimension of Rack Fixer (cm)", + "texts": [ + "6 Overview & Dimension of the Frame 2 (P58) Figure 4.7 Overview & Dimension of the Wheel (P58) Figure 4.8 Scissor Lift Supporting Operator Cabin (P59) Figure 4.9 Hydraulic Pump (P59) Figure 4.10 Front View of Scissor Lift with Maximum Lifting Range (P60) Figure 4.11 Collapsed View of Lifting Fork Assembly (P61) Figure 4.12 Exploded View of lifting Fork Assembly (P62) Figure 4.13 Overview & Dimension of Fork Lid (P63) Figure 4.14 Overview & Dimension of Fork Support Frame (P64) Figure 4.15 Overview & Dimension of Rack Axle (P65) Figure 4.16 Overview & Dimension of Rack Fixer (P65) Figure 4.17 Overview & Dimension of the Fork (P66) Figure 4.18 Overview & Dimension of Spur Gear (P67) Figure 4.19 Overview & Dimension of Rack Motor (P67) Figure 4.20 Fork Horizontal Movement of the Forks (P68) Figure 4.21 Vertical Movement of the Forks (P69) Figure 4.22 Rotation of the Forks (P69) Figure 4.23 Overview & Dimension of Truck Body (P70) Figure 4.24 Isometric View & Front Drawing of Truck Seat (P71) Figure 4.25 Overview & Dimension of the Steering Wheel (P71) Figure 4" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002840_f_version_1665489054-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002840_f_version_1665489054-Figure7-1.png", + "caption": "Figure 7. Dynamic loads in the rototranslating-drum design. (a) Overview. (b) Rotational dynamics. (c) Translational dynamics.", + "texts": [ + " We can then divide the architectures into two groups, namely one group characterized by the rototranslation of the drum (rototranslating-drum, translating-motor, and Spline Winch design), and one group represented by the decoupling of rotation and translation for achieving constant cable direction exiting the drum, namely the spoolinghelper design. For each winch, the overall dynamics is: TM = J? \u03b8\u0308 + K\u03c4 (5) where TM is the motor torque, K is the winch transmission ratio, and J? the overall transmission inertia reduced to the motor axis. From a dynamic point of view, the first group of winches shares similar load distributions when transforming the motor torque into cable tension. The rototranslating drum is selected to provide a schematic representation (see Figure 7a). The drum rotational dynamics is given by (see Figure 7b): J\u03b8\u0308 + Ts + rD\u03c4CS = rSF (6) where J is the inertia of all the rotating components, Ts is the screw reaction torque, \u03c4CS is the tension component projected onto the drum cross-section, rSF = TM is the product between the shaft radius and the shaft reaction force, which equals the torque exerted by the motor. If we consider the relationship between the axial force Q and the torque TS exchanged in the screw/nut pair to be: TS = KSQ, KS = h 2\u03c0 m/rad (7) The translational dynamics of the drum are (Figure 7c): Q = \u03c4AX + MKS \u03b8\u0308 (8) where M is the mass of all translating components, and \u03c4AX is the component of \u03c4 directed as the winch axis. If we now remember helix geometrical properties, we have: \u03c4 = \u221a \u03c42 AX + \u03c42 CS, \u03c4AX h = \u03c4CS 2\u03c0rD (9) and substitute Equations (7) and (8) in (6), after some algebraic manipulation we finally get: Tm = rSF = ( J + K2 S M ) \u03b8\u0308 + (\u221a K2 S + r2 d ) \u03c4 (10) which compared with Equation (5) gives: J? = J + K2 S M, K = \u221a K2 S + r2 d (11) According to the provided analysis, it is possible to compare some of the winches\u2019 performances: \u2022 The rototranslating-drum design, though conceptually simple, suffers from three main drawbacks: \u2013 To transmit torque to the drum, the shafts that pass through the winches are subject to a radial force which may be critically higher than the cable tension by design since rd > rS; this means that these shafts need to be bulky enough, which in turns means that the drum radius (and thus the transmission ratio) cannot vary freely" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000214_f_version_1700289389-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000214_f_version_1700289389-Figure2-1.png", + "caption": "Figure 2. A 3D model of the robot.", + "texts": [ + "8 Mechanical arm end load (kg) \u22646 Mobile platform total load (kg) 500 Working radius of the robot arm (mm) \u2265500 Turning radius (mm) 0 Obstacle avoidance distance (mm) >300 Positional accuracy (mm) 20 3. Mechanical System Design Robots need to be capable of moving in all directions, positioning, grabbing, and reducing vibration. The mechanical system design includes two parts: the overall structure and the shock absorption design. 3.1. Overall Design The mechanical structure of the robot is mainly composed of a moving part, control part, and grasping part. The robot model is shown in Figure 2. Drop point 2 Drop point 1 Pick-up point Mobile robot Magnetic stripe track Initial hold point Figure 1. The process of robot feeding. Table 1. Design parameters of the mobile robot. Parameters Design Requirements Mobile platform size (mm) 800 \u00d7 1300 Mobile platform speed (m/s) 0.8 Mechanical arm end load (kg) \u22646 Mobile platform total load (kg) 500 Working radius of the robot arm (mm) \u2265500 Turning radius (mm) 0 Obstacle avoidance distance (mm) >300 Positional accuracy (mm) 20 3. Mechanical System Design Robots need to be capable of moving in all directions, positioning, grabbing, and reducing vibration. The mechanical system design includes two parts: the overall structure and the shock absorption design. 3.1. Overall Design The mechanical structure of the robot is mainly composed of a moving part, control part, and grasping part. The robot model is shown in Figure 2. Electronics 2023, 12, 4693 4 of 21 Electronics 2023, 12, x FOR PEER REVIEW 4 of 22 3.1.1. Moving Part The mobile part of the robot is a mobile platform for the mecanum wheel, consisting of a frame, mecanum wheel (OM Robot, MW203-F70, with diameter of 203 mm), damping suspension mechanism, motor, driver, battery and power circuit, magnetic strip sensor, and RFID card reader. The frame utilizes a platform of 50 mm \u00d7 50 mm angle steel construction. Two magnetic strip sensors are installed at the front and rear ends of the chassis, which are used to detect the magnetic strip offset forward and backward of the robot, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003285_f_version_1691568217-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003285_f_version_1691568217-Figure1-1.png", + "caption": "Figure 1. Kinematic chains of the delta robot.", + "texts": [ + " Section 3 presents an original derivation of the image Jacobian based on the VLCM-CSM methodology. In Section 4, a control approach for reconfigurable parallel robots is developed and several control laws based on this approach are synthesized for a reconfigurable delta-type parallel robot. Section 5 details the experimental setup and the experiments performed. Section 6 presents and discusses the results. Finally, Section 7 describes the authors\u2019 conclusions of this work and outlines opportunities for future work. Let us consider the delta robot in Figure 1; it consists of two platforms, one fixed and a mobile one, connected by three kinematic chains (numbered with index i = 1, 2, 3), evenly distributed about the vertical axis Z of the robot\u2019s fixed frame. In this typical configuration, the fixed platform is on top of the mechanism (horizontal element), and the mobile platform (i.e., the part where the end-effector is attached) is a small, horizontal element at the bottom of the mechanism. Each chain has two links; one end of the chain is connected to the fixed platform through an actuated, rotational joint placed at point Ai with joint variable \u03b8i1, and the other end is connected to the mobile platform through a passive universal joint (some designs use a spherical one), at point Ci", + " With this, we define a sphere per each kinematic chain with center B\u0303i, and the intersection of the three spheres with the smallest value on the Z axis will be P = x, which is the solution to the direct kinematics problem. This can be represented by the following system of equations: (B\u0303ix \u2212 Px) 2 + (B\u0303iy \u2212 Py) 2 + (B\u0303iz \u2212 Pz) 2 = L2 2 (8) It may be observed that this approach is valid regardless of whether R is constant or variable. For that, this solution is valid for a reconfigurable delta robot. Based on Figure 1, the following closed-loop geometric constraint system can be defined: \u2212\u2192 OP + \u2212\u2192 PCi = \u2212\u2212\u2192 OAi + \u2212\u2212\u2192 AiBi + \u2212\u2212\u2192 BiCi (9) which has the following matrix form:Px cos(\u03b1i)\u2212 Py sin(\u03b1i) Px sin(\u03b1i) + Py cos(\u03b1i) Pz + r 0 0 = R 0 0 + L1 cos(\u03b81i) 0 \u2212 sin(\u03b81i) + L2 sin(\u03b8i3) cos(\u03b8i2 + \u03b8i1) cos(\u03b8i3) \u2212 sin(\u03b8i3) cos(\u03b8i3 + \u03b8i1) (10) This can be rewritten as (xi + r) = R + L1i + L2i (11) Deriving with respect to time, we obtain the following result: x\u0307i = R\u0307 + L\u03071i + L\u03072i (12) for the reconfigurable robot, R has a variable derivative, while in the case of the robot without reconfiguration, the derivative of R is zero" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001533__ijtes.5.10003-1.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001533__ijtes.5.10003-1.pdf-Figure3-1.png", + "caption": "Fig. 3. Tendril robot design", + "texts": [ + " Conclusions are presented in section IV. Continuum robots, particularly in long thin cablelike variants, can be used to access and sense areas in deep and complex environments. We have recently, under NASA funding, developed and demonstrated cable-like continuum tendril robots for remote inspection [10]. See Fig. 2. These robots were designed based on springloaded concentric tube backbones. The tubes were made from carbon fiber. The tubes were actuated, in bending and extension, via remote tensioning of cables by D.C. motors (see Fig. 3). The overall robot was built of three serially connected three degrees of freedom sections (Fig. 3). Springs along the sections allowed the local length of the backbone to be varied by increasing or decreasing the tension on the set of tendons actuating that section. We focused on the specific application of inspection between, behind, and within the equipment racks in the International Space Station (identified as a target application for that project by technical project managers at NASA). A formal demonstration of the developed tendril robots performing the inspection within equipment racks in an International Space Station Mock-up environment was conducted at the NASA Johnson Space Center in June 2017 [10]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001138__336871_fulltext.pdf-Figure7.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001138__336871_fulltext.pdf-Figure7.1-1.png", + "caption": "Figure 7.1 Top View of the Forklift", + "texts": [ + "20 Support Frame Meshing Model (P108) Figure 6.21 Stress Analysis of Support Frame (P109) Figure 6.22 Strain Analysis of Support Frame (P110) Figure 6.23 Displacement Analysis of Support Frame (P110) Figure 6.24 Overall Weight of the Scissor Lift Load (P111) Figure 6.25 Scissor Lift Meshing Model (P111) Figure 6.26 Boundary Condition and Applied Force (P112) Figure 6.27 Stress Analysis of Scissor Lift (P112) Figure 6.28 Strain Analysis of Scissor Lift (P113) Figure 6.29 Displacement Analysis of Scissor Lift (P113) Figure 7.1 Top View of the Forklift (P115) Figure 7.2 Front View of the Forklift (P115) List of Tables Table 3.1 Comparison of Forklift Design Ideas (P48) Table 6.1 Analysis Result of Fork Model (P103) Table 7.1 Lift Truck Dimensions (P116) Chapter 1 Introduction Because of the varieties, different shapes, different packaging of the goods, loading and unloading has always been a heavy process during transportation. Forklifts were naturally invented and became the solution to this problem; they save time and space", + " There is no obvious displacement in the scissor which means no break during the loading process. The whole system is overall safe for use. Chapter 7 Design Evaluation The technical parameters describe the structural features and performance. It includes the general parameter, dimensions, weight, performance, wheels and electronic. Those parameters will be introduced in section 7.1 with figure illustration. In section 7.2 we will discuss the advantage of our forklift design. 7.1 Parameter of the Forklift Figure 7.1 and Figure 7.2 is the overall dimension of the forklift, including truck length, width, highest lifting range and highest distance from forks and ground. Table 7.1 is all the parameters that this forklift has, including dimensions, total weight, performance, tires, battery type, etc. 16 Wheel Base 1.5 m W T. 17 Total Weight Standard Truck 4459 kg P ER FO R M A N C E 18 Brakes Service Breaks Electric/Mechanical 19 Method of Operation Plugging 20 Tire Type Load/Drive Polyurethane/Polyurethane 21 Wheels Number, Front / Rear 2 / 1 22 Tire Size Load Wheels, Front 350 * 140 mm 23 Tire Size Load Wheels, Rear 400 * 160 mm EL EC TR IC 24 Battery Battery Type Lead Acid 25 Volts / Max Ampere Hours 48V / 1085AH 26 Weight, minimum 1200 kg 27 Electric Motors Drive Motor Rating (S2 \u2013 60 minimum rating) 7" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003056_f_version_1708933451-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003056_f_version_1708933451-Figure1-1.png", + "caption": "Figure 1. The proposed Pick&Eat design: (a) 3D cad model; (b) the built prototype of Pick&Eat at DIMEG, University of Calabria.", + "texts": [ + " This situation is influenced by factors such as continuous maintenance, significant size, and notably high costs. The cost issue is exacerbated by the lack of financial recognition from insurance plans and subsidies [25], with costs increasing in correlation with payload capacity and degrees of freedom, as also mentioned in [26]. Considering the current absence of a cost-effective, user-friendly, and easily portable solution, this study introduces the mechanical, electrical, and control design of the \u201cPick&Eat\u201d device as shown in Figure 1. This device is a wheelchair-mounted robotic arm designed to provide autonomous assistance to patients with upper limb paralysis during mealtimes. The proposed design has been meticulously engineered to prioritize flexibility, adaptability, efficiency, and ease of use. The device is designed to seamlessly adapt to wheelchairs of various sizes without causing disturbance or impedance. Additionally, the inclusion of an interchangeable end-effector allows users to select between a fork and a spoon based on individual preferences and needs", + " This situation is influenced by factors such as continuous maintenance, significant size, and notably high costs. The cost issue is exacerbated by the lack of financial recognition from insurance plans and subsidies [25], with costs increasing in correlation with payload capacity and degrees of freedom, as also mentioned in [26]. Considering the current absence of a cost-effective, user-friendly, and easily portable solution, this study introduces the mechanical, electrical, and control design of the \u201cPick&Eat\u201d device as shown in Figure 1. This device is a wheelchair-mounted robotic arm designed to provide autonomous assistance to patients with upper limb paralysis during mealtimes. The proposed design has been meticulously engineered to prioritize flexibility, adaptability, efficiency, and ease of use. The device is designed to seamlessly adapt to wheelchairs of various sizes without causing disturbance or impedance. Additionally, the inclusion of an interchangeable end-effector allows users to select between a fork and a spoon based on individual preferences and needs", + " Sec on 5 analyses the entire control architectur , providing tails on the el ctr nic configuration and high ighting the sen or components employed to ensur adequate d stable device operation. Section 6 repo ts the exp rimental results obtain d, demonstra ing both the feasibility and effectiveness of the proposed desig , the use of which claims significant independence f r users with upper limb paralysis. A preliminary v rsion of this p p r has been presented at the IFToMM World Congress 2023 held in Tokyo, Japan, [27]. Figure 1. The proposed Pick&Eat design: (a) 3D cad model; (b) the built prototype of Pick&Eat at DIMEG, University of Calabria. This manuscript is structured as follows: Section 2 details the mechanical design of the proposed Pick&Eat device, with particular emphasis on the preliminary analyses conducted and the modelling. Section 3 focuses on the kinematic analyses performed to characterise the device under consideration, in order to ensure proper operation and identify the different permissible configurations", + " Preliminary analysis conducted: (a) tracking the movement of the task to be performed with frontal view to the left and lateral view to the right (voluntary person in the image is one of the co-authors of this work); (b) logical State Diagram. Figure 3. Workspace and reachable points by the manipulator (note: in the figure hyphen (-) stands for a minus sign (\u2212)). 2.2. Design Overview In compliance with the design requirements and based on the preliminary analyses conducted, we adopted several creative tactical strategies in the design process. The use of morphological graphs facilitated the synthesis of the topology of our device, shown in Figure 1, by characterising it into three main modules: the frame, the central body, and the end-effector. The components of these modules were created by CAD modelling and then manufactured by 3D printing, ensuring a lightweight and functional design. The frame, visible in Figure 4a, with dimensions 260 \u00d7 300 \u00d7 195 mm3, is characterised by an L-shaped geometry specially designed to allow connection to several wheelchairs without interfering with the movement of the wheel. To facilitate future maintenance, there are two removable panels: the upper one secured with magnetic clips while the front one equipped with a linear guide for easy movement (Figure 4b)", + " The exploded view of the base, which can be seen in Figure 5b, allows the housing module to rotate by means of gear and bearings, ensuring the necessary movement by means of a servomotor (MG996R Digital Servo\u2014Stall Torque: 9.4 kgf cm (kg force centimetres), 4.8 V, 500 mA, 0.17 s/60\u00b0). Both manipulator arms, measuring 295 \u00d7 447 \u00d7 30 mm3, have been designed to ensure the movement necessary to bring the In compliance with the design requirements and based on the preliminary analyses conducted, we adopted several creative tactical strategies in the design process. The use of morphological graphs facilitated the synthesis of the topology of our device, shown in Figure 1, by characterising it into three main modules: the frame, the central body, and the end-effector. The components of these modules were created by CAD modelling and then manufactured by 3D printing, ensuring a lightweight and functional design. The frame, visible in Figure 4a, with dimensions 260 \u00d7 300 \u00d7 195 mm3, is characterised by an L-shaped geometry specially designed to allow connection to several wheelchairs without interfering with the movement of the wheel. To facilitate future maintenance, there are two removable panels: the upper one secured with magnetic clips while the front one equipped with a linear guide for easy movement (Figure 4b)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003053_f_version_1614169697-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003053_f_version_1614169697-Figure9-1.png", + "caption": "Figure 9. Von Mises stress distribution.", + "texts": [ + " The humanoid foot is composed of four bodies, three of which are in ABS rigid plastic (Table 2), and the middle of which is set to thermoplastic polyurethane (TPU) for his flexible mechanical properties, simulating the muscle part. Another key component is the spring\u2014shown in Figure 8\u2014in the forefoot, which passively improves the ability of the foot to adapt to the ground; the spring was modelled with a 2 mm diameter, five coils, and an 8 mm length, and alloy steel was chosen as material in order to simulate a commercial part. After setting all of the required parameters, a mesh was generated with the parameters in Table 3 to perform the FEA. Figure 9 shows the FEM nonlinear dynamic analysis stress results computed by the use of the Von Mises formulation. A maximum value of 2.57 \u00d7 106 N/m2 is observed in the upper part of the rigid midfoot, next to the connection to the compliant body. The maximum value is significantly smaller than the yield limit of the material, thus validating the proposed humanoid foot for an average walking gait. The behavior of the impact of the foot on the ground is obtained by applying the mean angle displacement taken from the analyzed subjects (see Section 2)", + " The results can be observed in the step-by-step effect of the load on the different bodies of the humanoid foot, as is shown in the linear displacement distribution reported in Figure 10: \u2022 Starting from the rigid body of the hindfoot, the angular displacement is applied to the ankle joint. The hindfoot is connected to the flexible body of the midfoot, which starts to deform. \u2022 When the angular displacement causes the foot to hit the ground, the midfoot is characterized by a stress concentration in the upper part, as per Figure 9. \u2022 The arc bottom part of the foot is loaded with a maximum tension of 1.57 \u00d7 106 N/m2, behaving as the human foot muscle when stepping. \u2022 The spring connecting the two bodies of the forefoot is stretched. This helps the foot to adapt to the ground, and the potential energy of the spring restores the neutral \u2018flat\u2019 position when the contact is released. These results validate the behavior of the proposed humanoid foot, showing that it acts similarly to the human foot in terms of stress while walking", + " Both the value of the infill and the 3D support pattern with which the infill was printed were optimized according to the surface curve of the compliant component through an FEA with constrained motion (as per the acquired gait). The correct relative positioning of the components is defined by male and female rectangular pins. Then, the components are locked together with interlocking shapes. Additionally, epoxy glue was added to the coupled surfaces in order to improve the strength of the connection, as it is the most loaded component of the system, as shown in Figure 9. The assembly of the entire foot is shown in Figure 11. The prototype of the humanoid foot is composed of a rigid hind foot, a flexible mid foot, and a rigid forefoot, which is made of three 3D printed rigid parts, namely the connection pin, the sole and the toe, and a commercial part, the spring. The prototype was scaled down from human size in order to fit a service humanoid robot design [10\u201312], and thus the whole foot can fit into a box of (146 \u00d7 52 \u00d7 41) mm; it weighs 57.80 g. As a preliminary test, the adaptability of the foot to different step heights was tested" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004201_8581687_08629932.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004201_8581687_08629932.pdf-Figure4-1.png", + "caption": "Fig. 4. Tridimensional CAD representation of the (a) Stretch-Pro 1M and (b) Stretch-Pro 2M. An ABS case is used to cover the active roller(s), and the electronic board [(12) and (13), respectively]. (c) Stretch-Pro 1M prototype, weight 80 g, and (d) Stretch-Pro 2M prototype, weight 103 g.", + "texts": [ + " This consists of two copper rings with a groove (5) integrated within the rotating cylinder (3), in contact with the two power supply wires of the gear motor so to keep electrical connector. Two torsional springs (8), with a stiffness of k = 120.1834 Nmm/\u25e6, are fixed to the frame (9) and placed in contact with the grooves of the copper rings (5). The springs are soldered to wires connected to the electronic board. In this manner, we ensure power supply to the motor, while avoiding wire entanglement. The active roller system can be used to implement the two stimulation strategies described in Sec. II. Fig. 4, shows a tridimensional representation and the real implementation of the Stretch-Pro 1M, Figs. 4(a) and 4(c), and of the Stretch-Pro 2M (OD and SD), Figs. 4(b) and 4(d) respectively. In the SP-2M the distance between the motors was chosen as a trade-off between the space constraints and the requirements for enabling two-point discrimination on the forearm [30]. Two custom electronic boards ((14) and (15) in Fig. 4) based on a Cypress PSoC (Programmable System-on-Chip) micro-controller are used to control the system. The two boards present similar features but of controlling one or two active rollers, respectively. The design of the electronic boards is open source and more information can be found on the Natural Machine Motion Initiative website, and in [21]. The modularity of the design and the dimensions of the Stretch-Pro represent a clear advantage with respect to other analogous state of the art solutions, which makes it more easily wearable on the user\u2019s body and/or integrable within the prosthetic socket" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003814_merical_analysis.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003814_merical_analysis.pdf-Figure7-1.png", + "caption": "Fig. 7. Experimental setup and corresponding numerical design with boundary condition for the applied force measurements of the SPA-1.", + "texts": [ + " In these analyses, the bending deformation of SPAs with respect to the cavity pressure is received as an output in order to compare with the free expansion experimental results. Afterwards, a geometrical surface, defined as a rigid body, is located 25 mm away from the tip of the SPAs in z direction to measure the bending forces. For each SPA, this analysis configuration is set and the contact body force between a rigid surface and SPA with respect to the cavity pressure is taken as an output in Marc Mentat (MSC Software Corporation). A load-cell is used to measure the experimental bending force received from the soft inflatable actuator as shown in Fig. 7. The pneumatic fluid pressure is applied into the numerical model to analyze the bending response of three different actuators for comparison purposes. The experimental results which are obtained from the experimental setup are investigated based on the bending displacement and the bending force for the three SPA designs. The numerical results which are generated by finite-element modelling are compared with the experimental results. To observe the comparison of the bending displacements, the experimental and numerical results are placed in Fig" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001818_8600701_08906066.pdf-Figure11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001818_8600701_08906066.pdf-Figure11-1.png", + "caption": "FIGURE 11. Position deviation of the peg and hole.", + "texts": [ + " The values of OA should satisfy (4): ROA = \u221a L2 + d2sin(\u03b2 \u2212 \u03b1) \u03b2 = arctan d 2L (4) Assume that the assembly peg moves upward in the positive direction and downward in the negative direction and that displacements in different directions will inevitably occur at points C and G\u2032. At this time, the peg has two-point contact with the outer edge of the hole, as shown in FIGURE 10(d). The geometric relationship reveals that the position of the hole center is on the vertical line of line C \u2032G\u2032 and the projection of the Z \u2032 axis of the assembly peg on the O-XY plane. To ensure that the position of the hole can be located when the peg rotates around the Z axis. The deviation O2B of the peg and hole must be smaller than the maximum deviation as shown in FIGURE 11(a). The deviation of the peg and hole is expressed as (5). R\u2032 < D 2 + d 2 cos\u03b1 (5) where R\u2032 is the value of the deviation O2B of the peg and hole. Substituting (3) and after transformation, the range of positional deviations of the peg and hole will have the following expression: R\u2032max = D 2 + d 2 cos\u03b1min R\u2032\u2032max = D 2 + d 2 cos\u03b1max (6) When the value of deviation R\u2032 of the peg and hole is equal to R\u2032\u2032max , the angle of inclination \u03b1 can be adjusted between \u03b1min and \u03b1max , and the optimum peg and hole deviation, as shown in the gray area of FIGURE 11(b), ranges between 0 and R\u2032\u2032max . The stage of posture adjustment has two steps: The assembly peg should be moved in the oblique direction, at speed V during time t . In the searching stage, the angle at which the peg rotates around the Z axis is \u03b8 . At the end of the searching, the coordinates of the compliant center in the O-XY plane are (Xo,Yo). The direction in which the peg moves is expressed as follows:{ X = Xo + Vtcos\u03b8 Y = Yo + Vtsin\u03b8 (7) In the process of moving the peg toward the hole, as shown in FIGURE 12(a), since the diameter of the hole is larger than the diameter of the peg, the line-segment EF at the edge of the hole has the same diameter as the peg and is perpendicular to the moving direction, as shown in Figure 12(b)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002698_12235_FULLTEXT01.pdf-Figure17-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002698_12235_FULLTEXT01.pdf-Figure17-1.png", + "caption": "Figure 17. Extrapolated nominal stress in welded joint.", + "texts": [ + " When a nominal stress is intended to be calculated by finite elements, the more precise option of the structural hot spot stress determination should be considered. 3.1.4. Nominal stress at weld toe To find the nominal stress in a FE model a plot is created of the stress along a path approaching the weld. The FE model often has a gradient near the weld that corresponds to the geometric stress. A simple rule to obtain the nominal stress is to extrapolate the linear part of the stress on the surface inwards against the weld, see Figure 17. In the example below the nominal stress could easily be determined but in most cases the reality never looks like in the fatigue codes. 3.1.5. Nominal stress at weld root /throat When the weld is sensitive to fatigue root cracking the analysis should be based on stresses at weld throat by calculating the weld weld stress \u03c3n,w. The weld stress is based on average stress components in the weld throat (similar to static design), see figure 18; the stress \u03c3\u2534 is the normal stress to the weld throat section, the stress \u03c4\u2534 is the normal stress to the weld throat section" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003742_8948470_09117139.pdf-Figure16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003742_8948470_09117139.pdf-Figure16-1.png", + "caption": "FIGURE 16. Uncertainty around vectors. The orange uncertainty clouds on RB1 and RB2 is from measuring the marker position using the Optitrack. The error cloud around the vector ends are introduced by the CT scan images measurements of the local translation from the markers on the RB\u2019s to the anatomical points inside the leg.", + "texts": [ + " On the tibia at the knee the point where the mechanical axis enters the tibia (when the leg is straight) is selected and at the ankle the point on the tibial mechanical axis at the end of the tibia is used just as it start to cross over into the AJC. There are known errors in the positional measurements, which directly effect the pose accuracy of the hip or knee joints. Strydom et al. [36] showed that the CT and Optical tracking errors are 0.3mm and 0.18mm, respectively. These errors are approximated by a spherical volume around each joint as shown in the vector diagram in Figure 13 and a leg in 118518 VOLUME 8, 2020 Figure 16. In considering the rotational error (\u03b5) in vector vt due to the maximum translation error (\u03c4 ) and the rotational errors due to measurement (\u03c6), as detailed in Figure 16: \u03b5a = arctan ( \u03c4 ||vt || ) (16) The same principle can be applied to the vector vf . Then the true angle between the two vectors (see Figure 13) can fall between the range defined by: \u2032 = \u00b1 (\u03b5a + \u03b5b + \u03c6a + \u03c6b) where \u03c6a = \u03c6b = \u03c6 \u2032 = \u00b1 (\u03b5a + \u03b5b + 2\u03c6) (17) for: \u03c9 = \u03b5b + \u03b5b + 2\u03c6 (18) \u03c9 is a symmetrical range around . V. EXPERIMENTS A. METHOD Ethical approvals were gained for three Cadaver experiments; using four legs; as detailed in Table 2 and conducted at the Queensland University of Queensland\u2019sMedical Engineering Research Facility (MERF) located on the Prince Charles Hospital campus in Brisbane, Australia", + " For the first set of experiments the robustness and accuracy of existing rigid bodies from Optitrack were tested. For the second experiment Customized rigid bodies were designed and tested for the femur, tibia and arthroscope. The designed RB\u2019s and CT scan measurements as shown in Figure 15. For the final experiment a refined process, CT scans and RB\u2019s designs were used. B. UNCERTAINTY VALIDATION Using the homogeneous transformation matrices and the cadaver experimental data, the analytical uncertainty calculated in section IV can be verified. Figure 16 shows the uncertainty error clouds for both the Optitrack system and CT scan measurement uncertainty around the vectors used to measure the angles. For an arbitrary leg vector v\u2032n (femur or tibia) calculated from the Optical tracking and CT scan positions, we can determine the vector range that include the measurement uncertainty: v\u2032n = Revn + ve Femur or tiba Vector (19) VOLUME 8, 2020 118519 with vn the femur or tibia vector, v\u2032n the vector including errors, ve the translational error (CT andOptical tracking) and Re is the rotational error matrix, which is defined by: Re = Rex(\u03c3 )Rey(\u03ba)Rez(\u03c1) = c\u03bac\u03c1 \u2212c\u03bas\u03c1 s\u03ba s\u03c3 s\u03bac\u03c1 \u2212s\u03c3 s\u03bas\u03c1 + c\u03c3 c\u03c1 \u2212s\u03c3 c\u03ba c\u03c3 s\u03bac\u03c1 + s\u03c3 s\u03c1 c\u03c3 s\u03bas\u03c1 + s\u03c3 c\u03c1 c\u03c3 c\u03ba where \u03c3 is the flexion error angle of the knee, \u03ba the varus error angle and \u03c1 the inner rotational error" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000483_f_version_1693811026-Figure8-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000483_f_version_1693811026-Figure8-1.png", + "caption": "Figure 8. Archimede rover wheels: (a) low grousers for Test Setup A, (b) high grousers for Test Setup B.", + "texts": [ + " Figure 7a shows the experimental setup of the DLR PEL sandbox, the tracking system, the tilting side of the sandbox, and the Archimede rover driving on a 20\u25e6 slope. Two different test setups were explored during the rover experiments. This had been done in order to evaluate the effect of the design of the wheels while driving over different ground substrates. Specifically, the two test setups are: Test Setup A The sandbox of the PEL had been filled with granular lava having grain sizes in between 1 mm and 5 mm and the Archimede rover has been equipped with a set of wheels with low grousers, which can be seen from Figure 8a. Test Setup B The sandbox of the PEL had been filled with the lunar regolith simulant EAC-1A [66], a very loose soft soil with submillimeter granularity. In this case, the Archimede rover has been equipped with a set of wheels with high grousers, which can be seen from Figure 8b. The two types of soil are shown and compared in Figure 7b. In the figure, the grain size is shown of the two kind of soils, which are compared to a scale. For both test setups, A and B, the test modes 1 and 2 were performed, namely the Drive on flat terrain and the Drive on inclined plane. This section reports and discusses in detail the most significant results that were obtained during the experiments done with the Archimede rover. The results obtained for horizontal terrain are presented and discussed first, followed by the results for driving on inclined terrain" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000763__pdf_10.1145_3418302-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000763__pdf_10.1145_3418302-Figure4-1.png", + "caption": "Fig. 4. The four cases of hesitation loops demonstrated in the \u03b4\u0307 (t ) vs. \u03b4 (t ) state space, where \u03b4 (t )= \u2016M (t ) \u2212Tm \u2016 \u2212 P (t ) \u2212Tp . Each case represents a spatial context between the two interacting agents\u2019 motions as outlined in Section 4.3. All hesitations loop around \u03b4\u0307 (t )= 0. The start and end points of the arrows indicate the starting and ending states of the agents\u2019 motions, respectively. Any state to the left \u03b4 (t )= 0 indicates that the partner is farther from the target than the main participant, whereas states to the right of \u03b4 (t )= 0 indicate that the partner is closer to the target than the main participant. States above \u03b4\u0307 (t )= 0 indicate that the speed of the main participant is faster with respect to the partner participant; states below \u03b4\u0307 (t )= 0 indicate that the speed of the partnering participant is faster than that of the main participant.", + "texts": [ + " Trajectories that move in the negative direction in the state space represent either that the partner participants were getting closer to the target than the main participant, or that the main participant was moving away from the target while the partner remained stationary. Likewise, only the trajectories that move from right to left while the partner is moving faster than the main participant (\u03b4\u0307 (t )< 0)4 are relevant to the discussion of hesitations. There are four cases of observed hesitations that describe the spatial contexts in which hesitations occur. Figure 4 provides a visual demonstration of the cases. This section outlines the Human-Human (HH) dyad\u2019s interaction dynamics that are represented in these cases and what the entering and exiting directions of a hesitation loop mean in these contexts: 30 \u2212 d\u03072 (t ) < 0. 4d\u03071 (t ) < d\u03072 (t ). ACM Transactions on Human-Robot Interaction, Vol. 10, No. 3, Article 24. Publication date: July 2021. Case 1. Hesitation samples, in this case, start with a state of (\u03b4 (t )> 0, \u03b4\u0307 (t )< 0). That is, the main participant is farther away from the target and moving slower than the partner at the onset of a hesitation (d1 (t ) > d2 (t ))", + " The main participant closes the distance gap as he/she gains speed and catches up to the speed of the partner (crosses \u03b4\u0307 (t )= 0 in the upward direction). The main participant is briefly faster than the partner, but quickly slows down with respect to the partner (crosses \u03b4\u0307 (t )= 0 in the downward direction). In some of the cases, the main participant immediately speeds up again with respect to the partner, suggestive of the main participant\u2019s second attempt at accessing the target (see Case 1 (a) in Figure 4). In other cases, the main participant continues to slow down, yielding to the partner (see Case 1 (b) in Figure 4). Case 2. In this case, hesitation samples start with a state of (\u03b4 (t )< 0, \u03b4\u0307 (t )\u2264 0). The value of \u03b4\u0307 (t ) is near zero, indicating that the partner participant may be engaged in some other activity (e.g., shuffling cards sideways on his/her side of the table) or at rest when the main participant starts his/her reach (i.e., \u03b4\u0307 (t )> 0). In the example depicted in Figure 4, the main and the partner participants are almost equidistant to the target at the onset of the main participant\u2019s motion. After the main participant is moving faster and is closer to the target, the partner starts to move towards the shared target. Either by a brief acceleration of the partner or deceleration of the main participant\u2019s motion (hesitation), the partner moves faster toward the target before the main participant re-attempts to continue his/her reach. The participants may go through multiple cycles in which one of the participants moves slower than the other, crossing \u03b4\u0307 (t )= 0 downward (see Figure 4 Case 2(a)). Alternatively, the partner may yield to the main participant (see Figure 4 Case 2(b)). Going through multiple cycles of the trajectory pattern is indicative of multiple re-attempts\u2014referred to as Re-attempts (RA)\u2014by the main participant to gain access to the target resource. Case 3. Cases 3 is a variation of Cases 1 described above. In Case 3, the main participant reaches for the target, but the speed toward, and subsequently, the distance to the target is overtaken by the partner who moves faster\u2014perhaps despite having started his/her reach later than the main participant. This dynamic brings the pair\u2019s tra- jectory to cross the \u03b4\u0307 (t )= 0 state downwards once before crossing it again in the manner described in Case 1. Case 4. Likewise, Case 4 is a variant of Case 2, where only the starting state of the dyad is different. The example Case 4 illustrated in Figure 4 shows a starting state where the main participant is farther away from the target than the partner. While the main participant is moving faster toward the target in the beginning, this is overtaken by the acceleration of the partner participant until the two agents are approximately equidistant from the target. Their speed and respective distances to the target lead them to eventually go through the same hesitation loop as described in Case 2 afterwards. Understandably, because \u03b4 (t ) and \u03b4\u0307 (t ) combine the effects of both the main and the partner participants, the zero crossings of the system depend on both agents\u2019 actions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002134_f_version_1707297781-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002134_f_version_1707297781-Figure9-1.png", + "caption": "Figure 9. Finite element analysis results of equipment with initial wall thickness.", + "texts": [ + "3 N by Equation (12): F = Gshank \u00b7 lshank + G f oot \u00b7 l f oot l , (12) where F is the lifting force, Gshank is the gravity of the shank, Gfoot is the gravity of the foot, l is the horizontal distance from the center of rotation of the lifting force, lshank is the horizontal distance from the center of gravity of the shank to the center of rotation, and lfoot is the horizontal distance from the center of gravity of the shank to the center of rotation. Based on the working conditions of the model in Figure 8, we established the finite element model of the actuating mechanism and conducted finite element analysis. The finite element model contained 8508 elements and 8653 nodes. The results are shown in Figure 9. It can be seen the Biomimetics 2024, 9, 98 10 of 13 maximum stress and maximum displacement of the model are less than the allowable stress and allowable displacement, meaning that the weight of the mechanism can be lightened further. Biomimetics\u00a02024,\u00a09,\u00a0x\u00a0FOR\u00a0PEER\u00a0REVIEW\u00a0 10\u00a0 of\u00a0 14\u00a0 \u00a0 \u00a0 lifting\u00a0force\u00a0for\u00a0the\u00a0shank\u00a0which\u00a0is\u00a0equal\u00a0to\u00a0the\u00a0reaction\u00a0force\u00a0from\u00a0the\u00a0shank\u00a0to\u00a0the\u00a0shank\u00a0brace,\u00a0 calculated\u00a0as\u00a038.3\u00a0N\u00a0by\u00a0Equation\u00a0(12):\u00a0 shank shank foot footG l G l F l ,\u00a0 \u00a0 where\u00a0F\u00a0is\u00a0the\u00a0lifting\u00a0force,\u00a0Gshank\u00a0is\u00a0the\u00a0gravity\u00a0of\u00a0the\u00a0shank,\u00a0Gfoot\u00a0is\u00a0the\u00a0gravity\u00a0of\u00a0the\u00a0foot,\u00a0 l\u00a0is\u00a0the\u00a0horizontal\u00a0distance\u00a0from\u00a0the\u00a0center\u00a0of\u00a0rotation\u00a0of\u00a0the\u00a0lifting\u00a0force,\u00a0lshank\u00a0is\u00a0the\u00a0hori\u2010 zontal\u00a0distance\u00a0from\u00a0the\u00a0center\u00a0of\u00a0gravity\u00a0of\u00a0the\u00a0shank\u00a0to\u00a0the\u00a0center\u00a0of\u00a0rotation,\u00a0and\u00a0lfoot\u00a0is\u00a0 the\u00a0horizontal\u00a0distance\u00a0from\u00a0the\u00a0center\u00a0of\u00a0gravity\u00a0of\u00a0the\u00a0shank\u00a0to\u00a0the\u00a0center\u00a0of\u00a0rotation.\u00a0 6.2.\u00a0Finite\u00a0Element\u00a0Analysis\u00a0of\u00a0the\u00a0Mechanical\u00a0Structure\u00a0 Based\u00a0on\u00a0the\u00a0working\u00a0conditions\u00a0of\u00a0the\u00a0model\u00a0in\u00a0Figure\u00a08,\u00a0we\u00a0established\u00a0the\u00a0finite\u00a0 element\u00a0model\u00a0of\u00a0 the\u00a0actuating\u00a0mechanism\u00a0and\u00a0conducted\u00a0finite\u00a0element\u00a0analysis.\u00a0The\u00a0 finite\u00a0element\u00a0model\u00a0contained\u00a08508\u00a0elements\u00a0and\u00a08653\u00a0nodes.\u00a0The\u00a0results\u00a0are\u00a0shown\u00a0in\u00a0 Figure\u00a09.\u00a0It\u00a0can\u00a0be\u00a0seen\u00a0the\u00a0maximum\u00a0stress\u00a0and\u00a0maximum\u00a0displacement\u00a0of\u00a0the\u00a0model\u00a0are\u00a0 less\u00a0than\u00a0the\u00a0allowable\u00a0stress\u00a0and\u00a0allowable\u00a0displacement,\u00a0meaning\u00a0that\u00a0the\u00a0weight\u00a0of\u00a0the\u00a0 mechanism\u00a0can\u00a0be\u00a0lightened\u00a0further.\u00a0 Figure\u00a09.\u00a0Finite\u00a0element\u00a0analysis\u00a0results\u00a0of\u00a0equipment\u00a0with\u00a0initial\u00a0wall\u00a0thickness.\u00a0 The\u00a0optimization\u00a0results\u00a0are\u00a0shown\u00a0in\u00a0Table\u00a03.\u00a0Size\u00a0optimization\u00a0was\u00a0performed\u00a0on\u00a0 the\u00a0model\u00a0using\u00a0Equation\u00a0(13),\u00a0where\u00a0the\u00a0wall\u00a0thickness\u00a0of\u00a0the\u00a0parts\u00a0is\u00a0the\u00a0independent\u00a0 variable,\u00a0the\u00a0allowable\u00a0stress\u00a0of\u00a0295.8\u00a0MPa\u00a0and\u00a0allowable\u00a0displacement\u00a0of\u00a08.3\u00a0mm\u00a0are\u00a0the\u00a0 constraint\u00a0conditions,\u00a0and\u00a0the\u00a0minimum\u00a0mass\u00a0is\u00a0the\u00a0objective\u00a0function:\u00a0 1 max max min 1 2 3 1 2 3 295.8MPa 8.3mm n j i j k M m j m f x k d \uff0c \uff0c\uff0c \uff0c \uff0c\uff0c ,\u00a0 where\u00a0M\u00a0is\u00a0the\u00a0total\u00a0mass\u00a0of\u00a0the\u00a0mechanical\u00a0structure,\u00a0mj\u00a0(j\u00a0=\u00a01,\u00a02,\u00a03)\u00a0are\u00a0the\u00a0masses\u00a0of\u00a0thigh\u00a0 brace,\u00a0shank\u00a0brace,\u00a0and\u00a0chute\u00a0plate,\u00a0f\u00a0is\u00a0the\u00a0mass\u00a0function,\u00a0xk\u00a0(k\u00a0=\u00a01,\u00a02,\u00a03)\u00a0are\u00a0the\u00a0wall\u00a0thick\u2010 nesses\u00a0of\u00a0the\u00a0thigh\u00a0brace,\u00a0shank\u00a0brace,\u00a0and\u00a0chute\u00a0plate,\u00a0which\u00a0are\u00a0design\u00a0variables,\u00a0\u03b4max\u00a0is\u00a0 the\u00a0maximum\u00a0stress,\u00a0and\u00a0dmax\u00a0is\u00a0the\u00a0maximum\u00a0displacement" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004201_8581687_08629932.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004201_8581687_08629932.pdf-Figure3-1.png", + "caption": "Fig. 3. (a) 2-D section of the active roller, and (b) 3-D CAD representation. The numbers indicate the components described in Section III.", + "texts": [ + " 2(c) and 2(d) illustrate the rotation commanded to the active rollers, while the straight arrows show the consequent stretch generated on the users skin. To obtain a modular system, reduce encumbrance and simplify the hardware/software complexity, we adopted a technological solution for the active rollers that can be used to implement the feedback strategies discussed in Sec. II. To this aim, we developed an active roller with a gear motor, whose output shaft is attached to a fixed frame. In this manner, the stator acts as the active rotational part in contact with the user\u2019s skin. Fig. 3 shows the mechanical parts of the system. The main subassembly of the feedback device is the active roller depicted in Fig. 3(a). This is composed of a geared-motor1(1), 1Maxon RE 6 equipped with a gearbox GP6A (gear ratio of 221:1) whose frame is connected to a rigid cylinder (3) through a rigid flange (2). The cylinder (3) has an external hyperboloid shape (min radius = 5.2 mm, max radius = 7.7 mm), which was chosen to conveniently fit with the shape of the arm. The hyperboloid surface is covered with a silicone2 layer (4) to increase the friction between the skin and the device. The active roller is mounted on a frame (9), in Fig. 3(b). The motor shaft (6) is connected to (9), through the flange (10). The back side of the roller is connected to (9) through a bushing (7) to allow the roller to rotate and support the external load.3 A magnetic encoder (11) (AS5045, by Austriamicrosystem) measures the motor frame rotation. With this architecture, the active roller can be controlled to rotate clockwise or counter-clockwise. It is worth noticing that the proposed design architecture was inspired by the technical solution adopted in [29]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002079_uated-18wjy59voz.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002079_uated-18wjy59voz.pdf-Figure3-1.png", + "caption": "Fig. 3: The overview of the fabrication process of the ASL. (a) The schematic of the stretchable heater layer. (b) The heater is embedded in SMP. (c) The SMP layer in the glassfiber frame. (d) The final module with silicone rubber enveloping the SMP layer.", + "texts": [ + " The modulus of elasticity of thermoplastic polymers change orders of magnitude around their glass transition point. This makes thermoplastics a good choice for adjustable stiffness layers for controlling the elastic properties of the Robogami joint. In this research, we use a shape memory polymer that has the advantage of higher strain recovery over normal thermoplastics. To regulate its temperature, we embedded a 70 \u00b5m thick stretchable heater in the SMP layer. The fabrication process of the heater and its integration with SMP are presented in [18]. The overview of this process is presented in Fig. 3a and 3b. The residual strain in the SMP layer highly affects the stiffness of the joints and hence the repeatability of the motion. To achieve a higher shape recovery, we embedded the SMP layer inside silicone rubber. To do so, we first embedded the SMP layer between two glass fiber layers as presented in Fig. 3c. The glass fiber layers act both as the frame for attaching the ASLs to the joints and also as the mold for casting the silicone layer. Fig. 3d presents the final form of the ASL. The holes in the SMP layer presented in Fig. 3b will shape silicone columns that would transfer the force between the silicone and the SMP (the design details are in [22]). In order to regulate the stiffness of the joints, we need to control the temperature of the SMP layer. we use the electrical resistance of the heaters which provides a measure 5 156 156.5 157 157.5 158 60 70 80 90 100 110 Heater resistance (\u2126) A S L \u2019s m a x im u m t e m p ra tu re ( o C ) Experiments Linear fit Fig. 4: The ASL temperature vs. the heater electrical resistance" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002230_vibration_shells.pdf-Figure1.4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002230_vibration_shells.pdf-Figure1.4-1.png", + "caption": "FIGURE 1.4.--Notation and positive directions of", + "texts": [ + " Thus, the force resultants acting on this face can be expressed asz, 0:j and, similarly, the force resultants on the face perpendicular to the #-axis will be [ qo ) a -h/2 [ _,) The positive directions of the force resultants are shown in figure 1.3. Similarly, the moment of the infinitesimal force a,.ds(_ _) dz about the 3-line is simply za,, ds(o_) dz and the moment resultant M, is obtained by dividing the total integrated moment over the thickness by B d3. Thus, the moment resultants are given by {M:,}: F\" ](i+Z zdz] J -h/2 (a,_ _ \\ /\u00a2_/ (1.74) J-h/_ ((_. ! \\ R./ and, consequently, have dimensions of moment per unit length of middle surface. The positive directions of the moment resultants are shown in figure 1.4. It is worthy to note that although z._=_. from the symmetry of the stress tensor, it is obvious from equations (1.72), (1.73), and (1.74) that N,_#N_ and M,_#Mo_ unless R,=Rm At this point the assumption will be made that the sh_ll material is homogeneous; in particular, that the elastic constants E and _ are independent of z. Thus, if equations (1.71) are substituted into equations (1.72), (1.73), and (1.74) and the integrations over z are carried out, E and v will be treated as constants. The procedure for a heterogeneous material will be discussed in subsequent chapters", + "111) and utilizing the rules for differentiation of unit vectors given by equations (1.19), the vector equation can be expanded into its three scalar components as follows: O(BN.)+_(ANe_)+_N.__OB N AB_a o+-_Q,+ABq,=O (1.112a) _(AN_)+O (BN.o)+___aNo. -'ff_OAN \"+-_ Q_'-j-ABAB qtJ=0 (1.112b) AB N AB N 0 B 0 -_. ,---_ _+_a( Q.)+-_(AQo)+ ABq,=O (1.112c) Let the total moments acting upon the faces defined by a =constant and by 13=constant be denoted by i)_, and _)_, respectively, where (1.113a) 9_e = (- M0\u00a2. + M_.\u00a2a) A da (1.113b) as shown in figure 1.4. On the other two faces of the element the corresponding moments are _,+ (0_,/0a) da and _+ (0_/00) dfl. Thus, the vector ew,:ation of moment equilibrium for the shell element is given by X dso_q--_ +mAB da dO=O (1.114) where the point 0 has been used as the reference origin for the moments; where the term (F. \u00d7_) ds_/2, for example, represents the moment of the force F, located by the position vector (dsa/2)_ with respect to 0; and where ds, =A da and ds_=B dO. Substituting equations (1.109), (1" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004794_72193_FULLTEXT01.pdf-Figure3.1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004794_72193_FULLTEXT01.pdf-Figure3.1-1.png", + "caption": "Figure 3.1: Unsafe terrain search along a line starting from the current stance foot position to the desired inverted pendulum based foothold.", + "texts": [ + " In order to acheive this goal, we introduce a gaussian correction factor which tries to scale down the feedforward and feedback terms in Eq. 3.3 in such such a way that a terrain adapted foothold objective can be used for foothold optimization. Therfore, we introduce a three step approach to compute the objective: CHAPTER 3. FOOTHOLD GENERATION 15 1. Terrain Edge Estimation - computes the terrain edge location and its size by searching for unsafe terrain along the line connecting current foot position to the desired LIP foothold position as shown in Fig. 3.1. 2. Gaussian edge avoidance - computes a modified objective using gaussian weighing function at the edge location to step away from edge location. 3. Stepping over the terrain edge - computes a desired foothold over the unsafe region if the current foot location is within a critical distance from the unsafe terrain location. The foothold score is continuously computed and updated into the foothold score layer of the elevation map. The foothold generation module requests for the closest unsafe terrain location along the vector from current foot position to the desired foothold over a service running parallel to the foothold score computation" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004658_f_version_1431338064-Figure9-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004658_f_version_1431338064-Figure9-1.png", + "caption": "Figure 9. (a) Cross section view of the turntable in the virtual model; (b) Actual image of the interaction of pulley and belt.", + "texts": [ + " A scissor lift powered by a lead screw design is selected for its capability of control and stability, along with being compact and having a large traveling range. For the goal of facing forward as discussed earlier, a ring-style turntable is attached to the bottom, allowing the scissor lift to pivot freely. Motion control is achieved by adding a timing belt wrapped around the outside of the turntable and held securely with a setscrew; then a pulley attached to a motor is also mated to the belt to give the system motion. The pulley motor assembly serves an additional purpose of applying tension to the belt by being mounted on slots. Figure 9 shows the virtual model\u2019s cross sectional view of the turntable and the actual image of how the pulley and belt interact. The scissor lift is a crucial component for this robot, as it took up the majority of design time and fabrication cost. The end result is a functional lift that is capable of rising 20 inches (50.8 cm) in a few seconds at maximum speed and can also sit at a compact minimum position. To group all connecting wires between the 3D Flash LIDAR camera at the top of robot and control electronics at the base, E-chain is designed and fabricated as one of the essential pieces of the scissor lift" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004156_f_version_1648191525-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004156_f_version_1648191525-Figure1-1.png", + "caption": "Figure 1. Trajectory tracking with a robot manipulator.", + "texts": [ + " In trajectory tracking the robot must follow a given path with a desired position and orientation. In this work, we propose a general approach to solve the trajectory path tracking problem for manipulator robots using metaheuristic optimization algorithms. The proposed method is independent of the structure of the robot and independent of the DOF of the robot. Manipulator robots work in the joint space. However, to interact with the 3D world its trajectory is defined with respect to a 3D coordinate frame, Figure 1. For such reason, a transformation between the desired 3D trajectory in the 3D space to the joint space of the joint variables is required. To solve the trajectory tracking problem robots must be able to solve the inverse kinematic problem. The objective of inverse kinematics is to obtain the required manipulator joint values for a given end-effector position and orientation. The inverse kinematic problem is complex to solve since it depends on the robot structure. If the robot has more degrees of freedom than the required degrees of freedom to perform a task (redundant robot) then there could be infinite solutions" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001071_9559726_09246671.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001071_9559726_09246671.pdf-Figure3-1.png", + "caption": "Fig. 3. Polishing disk is modeled as two rotational degrees of freedom mechanism, where l1 and l2 are link lengths, \u03b81 and \u03b82 are the joint coordinates, and c\u2217 and s\u2217 are the abbreviations for cos(\u03b8\u2217) and sin(\u03b8\u2217), respectively. \u03b6 is the directional vector of the last link.", + "texts": [], + "surrounding_texts": [ + "Some examples of the kinematic structure and the corresponding Jacobians for the most common machine tools are shown in Figs. 3\u20135. For the sake of simplicity and clarity, the tool kinematics is presented in the machine tool coordinate system. However, our approach requires that all entities are expressed in the robot base coordinate system. The mapping from the tool to the robot base coordinate system is given by the following formulas: p2 = Rt p\u03032 + pt , R2 = Rt R\u03032, J2,p = Rt J\u03032,p, J2,\u03c9 = Rt J\u03032,\u03c9, and \u03b6 = Rt \u03b6\u0303 , where tilde denotes the tool coordinates and pt and Rt are the position and orientation of the machine tool base in the robot base coordinate system, respectively. The position pt and orientation Rt must be carefully determined by a calibration procedure to ensure the operation of the complete system. More complex virtual mechanisms can be derived by combining these three basic shapes. One such case is shown in Fig. 6. Note that none of these virtual mechanisms has a kinematic singularity." + ] + }, + { + "image_filename": "designv7_3_0002296_f_version_1505819256-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002296_f_version_1505819256-Figure1-1.png", + "caption": "Figure 1. Transverse (left) and longitudinal (right) cross-sections of the four internal geometries used in the fabricated prototypes, showing insertion routes for the input tubing. (a) Simple1, simple side-pockets without supporting internal walls; (b) Simple2, simple side-pockets with two supporting internal walls; (c) Opposing, opposing side-pockets; (d) Parallel, four parallel pockets.", + "texts": [ + " Finally, the actuators need to be reliable and safe [5]. Thus, they should have a precise and accurate enough output, which should not change radically during use. Furthermore, they should be robust to not get damaged easily and have a low pressure to torque output ratio, to mitigate dangers, if they do get damaged. Considering these requirements and applying the four design principles, we produced the following three main functional designs. All of the designed actuators had the same basic dimensions (Figure 1), approximated to match the size of an average index, middle or ring finger, based on measurements by Buryanov et al. [29]. The root part had a connector groove for connecting the actuators to a test bench or a supporting orthotic structure on the hand. All pressure input tubing was inserted through the root part into the pockets. Each prototype had ready guide grooves around it for a radially-reinforcing string. These grooves were set to be at 2-mm intervals along the actuator. Overall, four different internal geometries (Simple1, Simple2, Opposing and Parallel) and four different reinforcement types (A\u2013D) were designed for five prototypes (Simple1-A, Simple2-A, Simple2-B, Opposing-C, and Parallel-D). Details of the differences in the prototypes\u2019 geometry and reinforcements are shown in Figures 1 and 2, respectively. These details are described further in the following sections. The first design, Simple1, had simple side-pockets for abduction-adduction on the sides of a bigger central pocket for flexion (Figure 1a). For this design, we made a variation, Simple2, which had supporting internal walls in the abduction-adduction pockets (Figure 1b). The goal was to test whether the supports would affect the actuators\u2019 response. Without supporting walls, the pockets were expected to balloon freely, leading to a relatively large sideways expansion, including towards the inside of the actuator. This expansion was expected to be limited by the supporting walls, thus directing it more towards the actuator\u2019s tip and increasing the force output in the wanted direction. The reinforcement helix was wound around the prototypes from the root to the tip and back again", + " This way, the thread was aligned straight and evenly on the sides. On the other parts of the actuators, the helix crossed itself on the sides. For prototype Simple2-B, the helix was wound in the opposite fashion (Figure 2b). A strain-limiting layer made of rayon net was embedded inside the silicone wall under the actuators (Figure 2a,b). The middle region was left free to let the actuators expand in length around the curvature of the MCP joint and to reduce the effect of flexion structures on the abduction-adduction function. The second design (Figure 1c) had two opposing pockets on each side of the flexion pocket. This design of the side-pockets, sometimes referred to as bellows-type [30] or pleated type [31], relied on opposing ballooning structures that press against each other to cause a bending motion. The side-pockets had their thinnest wall (1 mm) on the side on which the deformation needed to be largest, i.e., where the two walls were to press against each other. We considered the main advantages of the opposing pocket structure to be that it would concentrate the deformation to a limited area, leading to a more pivot-like response for abductionadduction, and separate it from the flexion function. For the prototype Opposing-C, the reinforcement helix was wound so that it was always crossing itself on the sides, except in the center, where it crossed itself under the actuator, and once on top, as it passed through the gaps between the opposing pockets (Figure 2c). The strain-limiting layer was embedded under the actuator in the same way as with the Simple prototypes, leaving the abduction-adduction part of the bottom free. The third prototype design (Figure 1d) was based on the idea of using multiple long pockets laid out in a symmetrical pattern along the length of the actuator. Differential inflation of the pockets would provide more control over the deformation, so that the finger joint motions could be adjusted to match the target motions. With a three-pocket design, it would be possible to achieve a full 360\u25e6 directional control of an actuator\u2019s free bending, as shown by Gerboni et al. [15]. However, in the case of hand motion assist, the major difference is that the finger presents an extra constraint for the actuator. Furthermore, the MCP joint has two perpendicular DoFs that we want to control separately. These aspects add specific restrictions for actuator geometry, which need to be considered in order to achieve and control the wanted motions. Using a four-pocket design, with pockets in a square pattern (Figure 1d), it would be possible to control the flexion-extension and abduction-adduction motions by applying pressure to two pockets at a time and adjusting their relative pressures. For example, actuating the top pockets would make the top of the actuator expand, while the passive, relatively thicker bottom layer would limit the expansion, which would lead to a flexion motion. Similarly, when one or two left side pockets are inflated, the actuator would bend to the right, leading to abduction-adduction motion" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003593_0380310_10591748.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003593_0380310_10591748.pdf-Figure2-1.png", + "caption": "FIGURE 2. CAD model of actuator assembly.", + "texts": [ + " The space between the actuators under the robot\u2019s body is planned to accommodate a variety of sensing systems that can analyze the substrate for selective mining and localization purposes. Information regarding the size and mass of the prototype can be found in Table 1. The main electronics compartment is a waterproof Ensto polycarbonate enclosure, mounted on the top side of the frame. Positioning the electronics compartment on top of the robot body raised the robot\u2019s centre of mass but did not negatively affect stability. The robot\u2019s locomotion system comprises two actuators positioned at its sides, each consisting of two individually driven motor modules (Fig. 2). The two counter-rotating helices on each actuator allow to counteract the torque of the motor modules and enable isolated control of each DOF (Degree of Freedom). The number, positioning, and orientation of actuators were selected to allow holonomic control for 3-DOF planar motion and increased traction in wet and dry granular, as well as inclined terrains. The actuator design parameters were derived from literature and adjusted based on an experimental evaluation of the generated force and efficiency as follows: the drum length to drum diameter ratio was set to approx" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003872_conf_mse21_08004.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003872_conf_mse21_08004.pdf-Figure1-1.png", + "caption": "Fig. 1. Four-wheel drive platform for Mobile Manipulation", + "texts": [ + "ro \u00a9 The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). kinematics. The main goal of this paper is to create an anthropomorphic, redundant robotic arm with a simple structure, light weight, capable of manipulating objects with a mass of up to 0.2 [Kg] and a minimum energy consumption and which can be attached to a mobile platform with high manoeuvrability, such as the one in the below Figure 1. During the development of the project, aspects related to the mechanical structure of the arm, design, the kinematic part of the robot and the part of simulation and manipulation of a virtual model of the robotic arm were materialized. The conceptual result is a manipulator which acquires five degrees of mobility and a workspace comparable in shape to one of the human superior limbs, the dexterity being obtained with the help of the 5th class rotation joints. After consulting the literature, the mathematical equations for the corresponding kinematic part were determined, equations which are the foundation of a future virtual dynamic simulation [1-4]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001818_8600701_08906066.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001818_8600701_08906066.pdf-Figure1-1.png", + "caption": "FIGURE 1. Elastexttic displacement device.", + "texts": [ + " In Section V, the assembly error is theoretically analyzed. In Section VI, to verify the proposed assembly strategy, peg-in-hole assembly experiments are presented by using a 6 degree of freedom (DOF) robot, peg and hole with a tolerance of 0.1 mm. In Section VII, we compare and analyze the propose assembly strategy with the current classical assembly strategy. Section VIII gives the conclusions of this paper. II. ELASTIC DISPLACEMENT DEVICE A. PROPOSED MECHANISM The main components of the elastic displacement device are shown in FIGURE 1. The spring is used to store the energy generated by the displacement. The displacement sensor is used to measure the displacement generated by the assembly peg during the assembly tasks. The ball spline is used to limit the twisting of the upper and lower ends of the device to ensure so that the device has only one degree of freedom. VOLUME 7, 2019 167535 The equipment is employed in the assembly strategy of the variable compliant center, which is installed at the end of the industrial robot. When the robot starts to assemble, the compliant center of the assembly peg will change due to the spring\u2019s elasticity, and the displacement sensor will generate a signal to determine the contact state of the peg and hole" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.39-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004284_88522_FULLTEXT02.pdf-Figure5.39-1.png", + "caption": "Figure 5.39: Concept 5:2 with the EMC feature not engaged", + "texts": [], + "surrounding_texts": [ + "Concept 5:2 can be viewed below in figure 5.38. The short sides are singular pieces but the connection interface differs from 5:1 and the other scrapped ideas. Instead of the pieces being pressed together they are slid into each other further lowering the risk of them being pulled apart when the frame is compressed.", + "Concept 5:2 modeled in CAD can be viewed below in figures 5.39 and 5.40. The first image is shown with the feature of EMC capability not engaged. In the second image the metallic strips is instead turned to face inward which means that the EMC capabilities are engaged.", + "The six concepts that were chosen from the second brainstorm were put under evaluation by the same participants as workshop 1:2 and commented. The feedback covered possible issues and positives, but also questions regarding how certain features and functions were supposed to be solved or if some could be added. These are the final concepts that will only later on undergo refinements for improved functionality.\nThe feedback was as earlier given in written form and can be viewed below in table 5.5." + ] + }, + { + "image_filename": "designv7_3_0003588_6-3417_11_3_1203_pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003588_6-3417_11_3_1203_pdf-Figure1-1.png", + "caption": "Figure 1. Robotic arm vector model composed of the universal rota ional modules (URM) modules.", + "texts": [ + " 2021, 11, 1203 3 of 15 module. Such modules have a single degree of freedom, namely the rotational one. The rotation happens around the module\u2019s main axis and is not limited in the interval under consideration ranging from 0 to 360 degrees. The rotation may occur continuously in either direction of rotation without limitation. The modules and joints are contemplated to be perfectly solid bodies. The individual modules\u2019 axes of rotation cross each other at the point where they are joined by passive joints, Figure 1. The distances of section points in space are quantified by the ri vector (a kinematic chain segment), and this vector has its own Cartesian system of Si{Oi, xi, yi, zi}. The segment\u2019s rotation around the zi axis is defined by the rotation matrix Rzi(\u03d5i) [3\u20135]. The segment\u2019s rotation around the yi axis is defined by the rotation matrix Ryi(\u03d1i). Appl. Sci. 2021, 11, x FOR PEER REVIEW 3 of 15 or another device. Thus, the position of a point [pxi, pyi, pzi] on the module will be defined by the function of the rotation positions \u03c6i, \u03d1i and the segment size of the structure at hand\u2014|ri|; pi = f(\u03c6i, \u03d1i, ri)", + " The basis of the arm [1,2] is an autonomous, cylinder-shaped module. Such modules have a single degree of freedom, namely the rotational one. The rotation happens around the module\u2019s main axis and is not limited in the interval under consideration ranging from 0 to 360 degrees. The rotation may occur continuously in either direction of rotation without limitation. The modules and joints are contemplated to be perfectly solid bodies. The individual modules\u2019 axes of rotation cross each other at the point where they are joined by passive joints, Figure 1. The distances of section points in space are quantified by the ri vector (a kinematic chain segment), and this vector has its own Cartesian system of Si{Oi, xi, yi, zi}. The segment\u2019s rotation around the zi axis is defined by the rotation matrix Rzi(\u03c6i) [3\u20135]. The segment\u2019s rotation around the yi axis is defined by the rotation matrix Ryi(\u03d1i). The r1 vector is connected to the base perpendicularly to the plane with the x1, y1 axes. p1 \u2261 r1, because the coordinate system is orthogonal. According to Figure 1, the following applies to the position vector p1: \ud835\udc91 = \ud835\udc79 (\ud835\udf11 ) \u00d7 \ud835\udc93 (3) According to Figure 1, the following applies to the position vectors p2, p3, p4, to pi: The r1 vector is connected to the base perpendicularly to the plane with the x1, y1 axes. p1 \u2261 r1, because the coordinate system is orthogonal. According to Figure 1, the following applies to the position vector p1: p1 = Rz1(\u03d51)\u00d7 r1 (3) According to Figure 1, the following applies to the position vectors p2, p3, p4, to pi: p2 = p1 + Rz1(\u03d51)\u00d7Ry2(\u03d12)\u00d7Rz2(\u03d52)\u00d7 r2 (4) p3 = p2 + Rz1(\u03d51)\u00d7Ry2(\u03d12)\u00d7Rz2(\u03d52)\u00d7Ry3(\u03d13)\u00d7Rz3(\u03d53)\u00d7 r3 (5) p4 = p3 +Rz1(\u03d51)\u00d7Ry2(\u03d12)\u00d7Rz2(\u03d52)\u00d7Ry3(\u03d13)\u00d7Rz3(\u03d53)\u00d7Ry4(\u03d14)\u00d7Rz4(\u03d54)\u00d7 r4 (6) Appl. Sci. 2021, 11, 1203 4 of 15 A general position vector formula of this pi structure will thus be: pi+1 = Rz1(\u03d51)\u00d7 [ r1 + i \u2211 k=1 [ k \u220f j=1 ( Ry(j+1) ( \u03d1j+1 ) \u00d7Rz(j+1) ( \u03d5j+1 ))] \u00d7 rk+1 ] (7) The resulting orientation of the ri vector defined by the Euler\u2019s angle can be seen in [27] according to the Rz(\u03b3)Ry(\u03b2)Rx(\u03b1) option will be determined from the relation below based on the final arm rotation: RZYX(i+1) = Rz1(\u03d51)\u00d7 i \u220f j=1 ( Ry(j+1) ( \u03d1j+1 ) \u00d7Rz(j+1) ( \u03d5j+1 )) (8) Generally speaking, the final shape of the RZYX(i+1) in terms of its i-segment will look as follows: RZYX(i+1) = a11 a12 a13 a21 a22 a23 a31 a32 a33 (9) where aij for i = 1, 2, 3, j = 1, 2, 3 are the matrix elements", + " Modeling in Matlab The kinematic model in Figure 3 was created in Matlab using the Simscape/Multibody toolbox, the dimensions of which reflect the reality and are given in Table 1. The module diameter or volume need not be of interest when making a kinematic assessment, as it has no effect on kinematic parameters. The model is composed of individual blocks that define its parts. In a nutshell, the model consists of a base identical to the \u201cbase\u201d of the reference system and the individual blocks representing the ri vector (a kinematic chain segment). As we can see in Figure 1, the \u201cvector r I\u201d block then consists of the \u201cURM\u201c module and a passive joint part. The modules are connected in places where each joint represents its own Cartesian system of the module, starting in point Oi. In this experiment, the last part of the passive joint, vector r7, was considered to be an effector. A measuring device (sensor 7) is connected to the effector r7, checking physical quantities (position, velocity, acceleration). Such measuring devices can be mounted on other modules, too. The Euler\u2019s angles\u2019 values are also available in three consecutive rotations around the axes, often marked ZYX", + "215 b5 128 r6 212.430 a6 42.215 b6 128 r7 42.215 1 1 Effector (last part of the pass j int). (a) (b) Figure 4. (a) Model visualization with hints of dimensions in Matlab-Simulink using the Simscape/Multibody toolbox. (b) Detail URM with a passive joint. The model is composed of individual blocks that define its parts. In a nutshell, the model consists of a base identical to the \u201cbase\u201d of the reference system and the individual blocks representing the ri vector (a kinematic chain segment). As we can see in Figure 1, the \u201cvector r I\u201d block then consists of the \u201cURM\u201c module and a passive joint part. The modules are connected in places where each joint represents its own Cartesian system of the module, starting in point Oi. In this experiment, the last part of the passive joint, vector r7, was considered to be an effector. A measuring device (sensor 7) is connected to the effector r7, checking physical quantities (position, velocity, acceleration). Such measuring devices can be mounted on other modules, too. The Euler\u2019s angles\u2019 values are also available in three consecutive rotations around the axes, often marked ZYX" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001650_32489_FULLTEXT01.pdf-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001650_32489_FULLTEXT01.pdf-Figure13-1.png", + "caption": "Figure 13. Theoretical and Working Profile (Alipiev, 1988)", + "texts": [ + " - Influence of the modification on the geometry of the teeth The analyses of the formulas lead to the following conclusions: a) The modification of the profile cutting instrument does not change the diameter of the pitch circle of the epicycloidal wheel; b) Diameter of the addendum circle decreases when the coefficient of the modification - x of the profile cutting instrument is increased; c) The diameter of the dedendum circle increases when the coefficient of the modification is increased; d) When the coefficient of the modification of the profile cutting instrument is increased the tooth depth of the epicycloidal gear decreases; e) The addendum and the dedendum circles coincide and the tooth depth is equal to zero when the coefficient of the displacement is equal to 1. The mention above is illustrated in Figure 12 below. 2.1.5.Equations for teeth profile and curvature radius. 18 Biser Borislavov, Ivaylo Borisov, Vilislav Panchev - Determination of the theoretical and working profile of the epicycloid The teeth profile can be determined by formation of a profile generating circle q, which will move in relative motion. In order to do that, it is needed to form two movable Cartesian coordinate systems (shown in Figure13) : is the first one and it is in connection with profile generating circle , is the second one which is connected with the epicycloid circle. The equation of the profile generating curve in coordinate system is: ( (Eq 2.1.29) Where \u03be and \u03b7 are the coordinates of profile generating circle points. The centrodes of the profile generating curve are: r1 for epicycloid circle and rwo for generating circle. When the generating circle turns on an angle (\u03c8), the epicycloid circle will turn on an angle (\u03c6)" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004132_-8220_20_24_7249_pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004132_-8220_20_24_7249_pdf-Figure2-1.png", + "caption": "Figure 2. Mechanical components of the mobile platform. (a) Drive units; (b) drive units positioned at chassis.", + "texts": [ + " A vertical spring-loaded suspension for each individual wheel solves this problem [49]. However, such a suspension will lead to inaccurate positioning of the manipulator during motion. Usually, the floor in industrial production environments is almost flat. Under this assumption, a pivoting axle for two of the four wheels will result in a statically determined system. The displacement of the wheel support points during a pendulum movement is minimized by centering the pivot point of the pendulum axle in the radial axle of the wheels. Figure 2 shows the developed drive units and the chassis made from aluminum profiles. The drive units use a fixed/floating bearing for each wheel. Metal bellow couplings secure the servo drives against unexpected forces during motion. The pivoting axle is supported by rubber buffers to avoid direct contact between the pivoting drive unit and the chassis in extreme situations. The general technical specifications of the developed mobile platform are listed in Table 1. The collaborative manipulator UR5 is mounted on top of the mobile platform as shown in Figure 3" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.11-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000523_ploads_2018_11_9.pdf-Figure21.11-1.png", + "caption": "FIGURE 21.11. Effect of the shape of the bottom of the vehicle on the wake. (a) Bottom close to the ground and rough; (b) Streamlined bottom, at a greater distance from the ground.", + "texts": [ + ", the flow is no longer at rest with respect to the ground, and from point G a second boundary layer appears on the ground as well. Depending on the distance between the vehicle and the ground, the two boundary layers can meet in H or can remain separated. In the first case the flow is blocked and the air under the vehicle tends to move with it, giving way to another boundary layer starting from L. Between H and L a vortex may result. In the second case, the flow between the vehicle and the ground decreases aerodynamic lift, because of both the decreased size of the wake (Fig. 21.11) and the lower energy dissipation; if it is fast enough it causes a negative lift. The flow below the vehicle reduces the drag also, because the pressure in the wake is increased. All improvements which facilitate the flow under the vehicle have these effects: Either the distance between vehicle and ground is increased or the bottom is given a curved shape, in the longitudinal or transverse direction, or the bottom is supplied with a smooth fairing covering the mechanical elements that are usually in the airflow" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004479_f_version_1679279622-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004479_f_version_1679279622-Figure5-1.png", + "caption": "Figure 5. The parallel connection of the SWC robots.", + "texts": [ + " Figure 4 illustrates the mechanical design of the 2-DoF joint, which is connected to the active lock to achieve a pitch rotation (\u221245\u25e6 to 45\u25e6) and a yaw rotation (\u221215\u25e6 to 15\u25e6). More specifically, the 2-DoF joint of the robot module is composed of two linear motors, four spherical joints, a connecting base, a yaw joint, and a pitch joint. The linear motors (rated voltage: 6 V, length: 50 mm) connect to the connecting base and active lock through the spherical universal joints. Their lengths can be determined to achieve the target pitch and yaw angles based on the kinematic inverse solution [8]. B. The Parallel Connection Figure 5 details the parallel connection\u2019s mechanical structure, which enables the robot to realize steering through the differential speeds of the robots. To be more specific, a servo motor (rated voltage: 6 V) is installed at the rear of the SWC robot as a parallel connector. Based on this, two robots with the mirror-symmetrically installed servo motors can be connected in parallel through a servo arm. The angle between two servo motors\u2019 horizontal central axes is defined as \u03b1 with a range from 0\u25e6 to 30\u25e6. Furthermore, the number of SWC robots in the parallel connection is limited to 2. As shown in the right of Figure 5, the convex and concave connectors were designed to be distributed on the left and right sides of the SWC robot, respectively. As \u03b1 equals zero, the convex connectors are inserted into the concave connectors to enhance the parallel connection\u2019s stability. In this section, the kinematic model of the parallel-connected SWC robots is established as a basic locomotion mode. A single SWC robot can only move forward or backward in a straight line, so its linear velocity can be used to describe the locomotion" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003474_8600701_08701694.pdf-Figure7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003474_8600701_08701694.pdf-Figure7-1.png", + "caption": "FIGURE 7. Position control problem.", + "texts": [ + " The experiments are the following: Position Control, Trajectory Tracking, Path Following and Obstacles Avoidance. A. ROBOT POSITION CONTROL A simple control example has been implemented to test the platform. This experiment is entitled position control or point stabilization of a differential wheeled mobile robot. The objective of the experiment is to drive the robot from the current position C(xc, yc) and orientation of the robot with respect to the plane XY (\u03b8), to the target point Tp(xp, yp), as shown in Figure 7. Note that \u03b8 = 90\u25e6 at point C and \u03b8 = 0\u25e6 at point Tp. This problem has been widely studied mainly due to the design of the control law. Under the nonholonomic constraints, this experiment introduces challenging control problems from an academic point of view [27]. To achieve the control objective, the distance (d) and the angle (\u03b1) between the points C and Tp are calculated with Equations (1) and (2). d = \u221a( yp \u2212 yc )2 + ( xp \u2212 xc )2 (1) VOLUME 7, 2019 55889 FIGURE 8. Position control block diagram" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000731_8581687_08603747.pdf-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000731_8581687_08603747.pdf-Figure3-1.png", + "caption": "Fig. 3. Paper-balloon catching process. For paper-balloon catching, we used 4) a virtual damping controller in addition to the three control modules.", + "texts": [ + " It is difficult to investigate the relationship between the force and deformation, and defining a deformation model for the paper balloon is not easy. Moreover, a tactile sensor cannot detect contact before deformation because the surface deforms significantly on applying an extremely small force. Even if a fingertip is immediately stopped at the surface, the surface will be deformed considerably owing to the impact force and vibrations of the fingertip. To catch the paper balloon gently, we used 4) a proximitybased virtual damping controller in addition to the above three control modules, as shown in Fig 3. The proximity-based virtual damping controller decreases the fingertip speed continuously based on the differential value of the detected distance. The impact force and vibration of the fingertips were reduced by the controller and the amount of deformation became small. In high-speed catching of rigid objects, many studies used a vision sensor with a detection or estimation algorithm for appropriate catching. Namiki et al. [1] developed a high-speed multifinger robot hand and demonstrated the dynamic catching of a rigid object by using the hand and 1 ms visual feedback" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.7-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.7-1.png", + "caption": "Fig 5.7 Pressure Regulator", + "texts": [], + "surrounding_texts": [ + "The Single-Acting Cylinder is a spring-return cylinder. It converts fluid energy into linear mechanical energy which can be used to perform work in only one direction. It has one connection port labelled Cap End Port. When air flow is directed toward the Cap End Port of the cylinder, pressure in the cap end rises until enough force is generated to compress the spring, and the cylinder rod extends. When the air pressure is released, the force of the spring makes the cylinder rod retract. The cylinder rod can also be extended and retracted manually. To do so, place the mouse pointer on the cylinder tip. The arrow pointer changes to a hand pointer. Click the 43 mouse left button and drag the rod outside or inside the cylinder. Then release the mouse left button." + ] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-73-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure70-73-1.png", + "caption": "Figure 70-73. 25-1/2-inch Road Whee/ Assembly {Light Tank)", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\nFigure 10-11 represents a vehicle possessing\nfive independently sprung wheels on each side. If the deflection, in inches, of the individual springs is denoted as fu h, fa . . . \u25a0 f\u201e, the following n equations are obtained.\nW, = eU\nWo = c/2\nWa = oft\n(10-26)\n(10-27)\n(10-28)\nWn Cfn (10-29)\nwhere Wi .... Wn = load acting on each wheel, lb c = rate of individual springs (assumed equal),\nlb/in.\nThe deflection of the springs can be expressed by the following (\u00ab-!) equations\nh = A + h tan 0\n= A + h tan 0 /:\n(10-30)\n(10-31)\nf\u201e = fi+ln tan\u00a9 (10-32)\nFinally, two more equations can be written\nWl + Wi+Wa+ Wn = W (10-33) Wa h + Wa h + Wn h =Wlo (10-34)\nThe total number of equations will be (2n-\\-1),\nand tlie total number of unknowns will also be (2n+l), i.e., n forces, W; n deflections, /; and the angle 0. This permits the determination of the unknowns by algebraic manipulation.\n10-13.4.2 Dynamic Loads\nDynamic loading acting on the road wheels is extremely complex owing to the nature of the input forces. Dynamic loading of the road wheels and related components results from vehicle acceleration, braking, turning maneuvers, gun recoil, ballistic impact, blast, or the terrain. Two aspects of\ndynamic loading are discussed in Section II of\nChapter 2, and in Section [I of this chapter.\n10-13.4.3 External Forces\nGun recoil loads are transmitted through the gun mount and vehicle structure into the earth. As part of the vehicle structure the road wheels are subjected to the dynamic recoil loads. The gun recoil loads are obtained by established methods of calculation and by field testing.\nThe investigation should be conducted for different angles of elevation and azimuth. For the calculated loading, short peaks or spikes in the recoil data of less than 3 milliseconds duration have no appreciable effect and can be neglected (Kef. 8).\n10-14 TIRE DESIGN (Ref. 23)\nBogie and road wheel tires are constructed of solid rubber vulcanized to a. steel wheel. Considerable testing and development has gone into the design and construction of these tires. Many rubber compounds, both natural and synthetic, have been tried in an effort to increase durability. A variety of tire width-and-thickness combinations have been used, together with tread designs such as annular grooves. As a result of this extensive development program, three important design requirements have been established:\n(a) Tire width should not be more than seven\ninches. If more width is required, two tire sections should be used instead of one. Lateral shearing forces set up at the steel\nbase by the extreme distortion of the rubber load are thus reduced.\n(b) Tire diameter should be as large as practicable because the load-carrying capacity of tires of the same width varies approximately as D to the 2.25 power, where D is outside diameter. This factor was established primarily as a function of the heat build-up in a tire under rated load and speed.\n(c) Tread thickness should be limited to an amount necessary to overcome the danger of blowout where heat developed by flexing may actually break down the rubber in the center of the tread section. At present, the\n10-15", + "AMCP 706-356\ntire thickness of medium and heavy tanks is 1-5/8 inches and of light tanks, 1-11/32 inches.\nOther factors affecting tire life are type of suspension, and tank mass and speed. Tanks with soft springs and independent suspensions affect tire life less than tanks with bogie-type suspension and stiff springs with high friction linkages. Soft, frictionless springs reduce peak impact loads on tires, particularly on a solid mass of rubber vulcanized to a steel base.\nMass of the tank affects tire life in that the heavier the tank the higher the inertia forces acting when the mass oscillates over rough terrain. Since kinetic energy varies directly as the mass and as the square of the speed, forces are set up in component parts of the suspension which cannot be estimated unless measured dynamically, especially on tracklaying vehicles operating on grades. During such slope operations, test data show that an appreciable change in load distribution takes place on front and rear road wheels while the load on the center wheels remains approximately constant.\n10-15 WHEEL DISC DESIGN (Refs. 24, 25, 26)\n10-15.1 CHARACTERISTICS Basic design objectives in the development of a road wheel are: (a) high strength-to-weight ratio, (b) rigidity, (c) minimum weight, (d) reliability,\nand (e) adaptability to manufacture. These objectives have been the bases for the evolutionary process that has produced the various types of road wheels.\nThe approach to road wheel design has been largely empirical. The typical road wheel of tracked vehicles at the beginning of World War II was of welded steel construction. It had an integral hub and rim, and a single flat disc with lateral ribs or gussets. The disc was cut out between the ribs to reduce weight. The tire was molded to a separate steel band which was pressed onto the wheel. Shortly thereafter, the first designs were modified to a type that was better adapted to mass production techniques and was less expensive to make. The modified wheel used a lighter gage stock and was formed by using two symmetrical stampings for the disc; these were riveted to each other and to the rim. The tire was attached as before.\nThe next typeof road wheel, developed during World War II and used on medium and heavy tanks, is shown in Figure 10-12. In this design, the pressed on rim was eliminated and the tire was molded directly to the wheel. A wheel used extensively on light tanks during World War II and in Korea is shown in Figure 10-13. While this wheel is somewhat similar to the wheel shown in\n10-16", + "AMCP 706-356\nthe two-piece welded construction. The principal advantage in this type of construction is its economy of manufacture made possible by the lighter service requirement permitting the use of lighter gage low alloy steel.\nA later design is presented in Figure 10-14. This wheel represents some of the basic features of present-day one-piece track wheels. It has a tapered disc which supports the rim at its center. This not only provides the rigidity inherent in the cone shape of the disc, but it also supports the rim at its optimum point\u2014its center. After assembly to the disc, the rim flange is turned inward forming the reinforcing rim.\nFigure 10-15 shows a wheel designed for amphibious tracked vehicles. Wheels for amphibious vehicles are designed so they provide a significant flotation factor. This is accomplished by incorporating water tight chambers into the design, or chambers filled with styrofoam.\nFigure 10-16 shows a steel wheel design for a flat track suspension system. Figure 10-17 shows a recent aluminum wheel design for the same type of suspension.\nIn keeping with the objective of high strength/ weight ratios for road wheels, forged aluminum road wheels have been developed. Forged aluminum (2014-T6) road wheels have given excellent service on the M60 Main Battle Tank and are the standard units on these vehicles. Currently, forged aluminum road wheels are under development for\nthe New Main Battle Tank. The requirements for this wheel included 44,000-pound radial load, 32,- 000-pound side load and a minimum life of 4,000 miles in a 30-inch diameter wheel weighing 95 pounds or less, including rubber and metallized wear surface.\nThe use of aluminum alloy for road wheels has introduced the need for additional wear protection in the track guide area. Several approaches to this problem have been considered. One method of achieving adequate wear surfaces on the wheels is\nto provide replaceable steel wear rings as part of the wheel assembly. These rings are positioned to contact the track center guides during operation of the vehicle. Another method consists of extending the tires so that they contact the center guides. An advanced technique consists of coating the wear surfaces with a steel alloy spray deposit. Spray-applied Metcoloy No. 2 has proven suitable for this application.\n10-15.2 TESTING PROCEDURES AND STRESS ANALYSIS\nIn road wheel design, as in many other fields, laboratory tests are invaluable in the development of particular designs. Four basic techniques are widely used to study and evaluate road wheels in the laboratory, namely: (a) dynamic destructive fatigue tests, (b) impact tests, (c) static load-deflection tests, and (d) strain distribution tests.\n10-17" + ] + }, + { + "image_filename": "designv7_3_0002601_onf_pt2020_01007.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002601_onf_pt2020_01007.pdf-Figure2-1.png", + "caption": "Fig. 2. Harmonic drive two stage assy.", + "texts": [], + "surrounding_texts": [ + "The specifications show that the speed of rotation of the antenna and therefore the output of the reducer is: (1) In addition, for the output torque: (2) For the reducer designed the pair of flex spline-gear rings, they are shown in the figure below. The values of the number of teeth were selected and therefore the transmission ratios were as follows: (3) (4) =55 (5) (6) (7) Now calculating the power conservation for each stage we obtain the following relationships: (8) (9) (10) Where: \u03c9in = engine speed \u03c901= the speed of rotation at the output of the first flex spline \u03c912= the rotation speed at the output of the second flex spline For the completeness of the balance sheet, of course, the losses at each level are taken into account, which are practically perceived through the individual performance ratios. Thus, we have n01 = the efficiency of the first stage n12 = the efficiency of the second stage Combining now the rotational speeds per stage as well as the transmission ratios we have: (11) (12) (13) (14) From the relationships that correlate the power of each stage with the corresponding efficiency we obtain: (15) (16) We therefore come to the two basic relationships that determine the characteristics of the engine required to meet the relevant specifications: = (17) (18) Among the values already mentioned are: Mout=1700Nm itot=3025 Finally, regarding the total efficiency, a standard for plastic speed reducers (main loss resulting from the internal lag of the elastic parts) was used: ntot=0.75 Therefore, the motor needs to fulfil the following specificiations: \u03c9stepper=5.58RPS Mstepper=0.75Nm" + ] + }, + { + "image_filename": "designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000179_ATHE_20HEADSTOCK.pdf-Figure1-1.png", + "caption": "Figure 1: Part assembly of the spur gear prepared in solid works", + "texts": [ + " Though an approximation, the contact aspects of such gears can be taken to be equivalent to those of cylinders having the same radii of curvature at the contact point as the load transmitting gears have. Radius of curvature changes continuously in case of an involutes curve, and it changes sharply in the vicinity of the base circle. In this paper, grey cast iron, high carbon steel and medium carbon steel are used as the spur gear materials. The material properties of steel and grey cast iron are given in Table 1. http: // www.ijesrt.com \u00a9 International Journal of Engineering Sciences & Research Technology [322] The CAD model of the spure gear is prepared in solid woks software as shown in figure 1. The dimensions of the gear is refered from M. Raja (2014) in which the same headstock spur gear is used and are given in table 2. Theoretical calculations of Contact Stresses by Analytical Method (Hertz equation) Hertz equation is used to determine the contact stresses in the mating teeth of gear. Hertzian eqution for contact stress in the teeth of mating gears is given by, \ud835\udf0e\ud835\udc50 = \u221a \ud835\udc39\ud835\udc61(1+ \ud835\udc45\ud835\udc54 \ud835\udc45\ud835\udc5d ) \ud835\udc45\ud835\udc54\ud835\udc4a\ud835\udf0b[(1\u2212\ud835\udf101 2)/\ud835\udc381+(1\u2212\ud835\udf102 2)/\ud835\udc382]\ud835\udc60\ud835\udc56\ud835\udc5b\ud835\udf19 (1) http: // www.ijesrt.com \u00a9 International Journal of Engineering Sciences & Research Technology [323] Where \u03c3c = Contact stress in mating teeth of spur gear, Ft is the tangential load, Rg and Rp are the pitch circle radii of gear and pinion, W is the face width, \u00d8 is the pressure angle, \u03c5 = poissions ratio, E1 and E2 are the modulii of elasticity of two gears in mesh" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003007_d-Sutherland-PhD.pdf-Figure3-6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003007_d-Sutherland-PhD.pdf-Figure3-6-1.png", + "caption": "Figure 3-6 Torso system model.", + "texts": [ + " His torso attitude correction algorithm is of secondary importance. In Torso Driven Walking, the Torso Attitude Controller is the key component for maintaining balance. 3.2.5.2 Implementation i. Torso system model Everything above the waist of the biped robot is treated as part of a single rigid link, called the torso. In the interests of increasing simplicity, the influence of arm, head and 72 flexible torso movement on the robot has been disregarded in the development of a system model. The simplified 3-D system model is shown in Figure 3-6. For the purposes of this discussion, only the planar case is considered (which is an approach taken in the experimental investigations as well). As a result, the system model can be simplified further, as in Figure 3-7. 73 The left and right motor torque is known, so if frictional torque is assumed to be negligible, BASE\u03c4 can be calculated: RIGHTLEFTBASE \u03c4\u03c4\u03c4 += (1) The translational forces ( xf , yf ) transmitted to the torso by the robot\u2019s legs come from three primary sources: 1) Transmitted ground reaction force through the supporting leg 2) Dynamic forces induced by the free leg\u2019s swinging motion 3) Collision impulses as the free leg strikes the ground All of these translational force components are difficult to calculate on-line, and require an accurate system model to give meaningful results" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000549_f_version_1722761863-Figure13-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000549_f_version_1722761863-Figure13-1.png", + "caption": "Figure 13. Overall structure.", + "texts": [ + " In order to realize the synchronous steering of the foot robot, the diagonal midpoint O is selected for use as the center of the driving link. The distance of the AO section is known, and the length of link AE is unknown. Considering that the length of the link AE cannot exceed half of the platform width AB, and the two closed-chain single-leg mechanisms on the same side cannot interfere with each other when turning, the length of link AE is determined to be 60 mm in the experiment. Finally, the overall structure of the walking foot robot is designed, which is shown in Figure 13. 4.2.1. Calculation of Degrees of Freedom The movement diagram of the steering mechanism is shown in Figure 14. According to the degrees of freedom calculation method for the planar mechanism, the number of degrees of freedom can be obtained. This value is calculated as follows: F = 3n \u2212 2P1 \u2212 Ph = 3 \u00d7 9 \u2212 2 \u00d7 13 \u2212 0 = 1. (49) 4.2.2. Kinematics Analysis The core structure of the steering mechanism to achieve steering adopts the parallelogram structure, as shown in Figure 15. Therefore, the parallelogram structure is taken for further analysis" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004824_f_version_1680588195-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004824_f_version_1680588195-Figure2-1.png", + "caption": "Figure 2. Structure of the silicone SSAs with mechanical connections and electrical connections.", + "texts": [ + " The selection of contact methods depends on the object and gripper contact surfaces. Geometric contact methods include points, lines, and surfaces. Surface contact is frequently preferred since it offers the most extensive contact area, thereby maximizing the grip pressure of the gripper. The finger jaws are designed with the SMA coil to adjust the joint stiffness for stably holding an abject, as described in Section 2.3. 2.2. Conceptual Design of Silicone SSAs The mechanical and electrical connections of the SSAs are illustrated in Figure 2. The SMA spring is attached to two M3 screw hooks by wrapping copper wire around them and soldering them with tin. As the SMA spring is a conductive material that changes phase when heated, an electric current is utilized to induce heating. The electric wires are connected to the SMA spring at the ends of the spring with soldering joints. To measure the actual temperature of the spring, a thermistor sensor is placed on the first coil of the spring. Additionally, in order to prevent direct contact with water during the cooling process, the sensor is covered with a small block of silicone", + " The selection of contact methods depends on the object and gripper contact surfaces. Geometric contact methods include points, lines, and surfaces. Surface contact is frequently preferred since it offers the most extensive contact area, thereby maximizing the grip pressure of the gripper. The finger jaws are designed with the SMA coil to adjust the joint stiffness for stably holding an abject, as described in Section 2.3. 2.2. Conceptual Design of Silicone SSAs The mechanical and electrical connections of the SSAs are illustrated in Figure 2. The SMA spring is attached to two M3 screw hooks by wrapping copper wire around them and soldering them with tin. As the SMA spring is a conductive material that changes phase when heated, an electric current is utilized to induce heating. The electric wires are connected to the SMA spring at the ends of the spring with soldering joints. To measure the actual temperature of the spring, a thermistor sensor is placed on the first coil of the spring. Additionally, in order to prevent direct contact with water during the cooling process, the sensor is covered with a small block of silicone", + " The M3 screw hooks, which attach to the ends of the spring, connect to the plastic caps by threads. One cap on the left of the SSA is fixed on the gripper frame, and the other links to a tendon to actuate the gripper. Because of water cooling, there are two silicone tubes (inlet and outlet) with an outer diameter of 3 mm connecting to the SSA. Actuators 2023, 12, x FOR PEER REVIEW 5 of 18 the gripper. Because of water cooling, there are two silicone tubes (i let and outlet) with an outer diameter of 3 m connecting to the SSA. Figure 2. Structure of the silicone SSAs with mechanical connections and electrical connections. 2.3. Design of the Gripper Jaw with Stiffness Control The finger shown in Figure 3a was inspired by a surgical robot that can change its joint stiffness [32]. The finger was 3D-printed using polylactic acid (PLA) and had revolute joints linking the entire finger, with each finger actuated by two tendons. Figure 3a,b illustrate the robot link\u2019s structure with two linkages and a rotational joint. To increase the grasping ability of the tendon-driven gripper, a silicone pad is attached to the end effector linkage", + " Moreover, as the inner diameter of the spring is smaller than the diameter of the sum of two adjacent shafts at the austenite state, the spring exerts a compressive force, resulting in a tightening effect (Fr). Finally, the fixed base of the finger has a groove on two sides for easy assembly with the gripper\u2019s frame, making it a modular design. The prototype of the gripper jaw is depicted in Figure 3d. Actuators 2023, 12, x FOR PEER REVIEW 5 of 18 the gripper. Because of water cooling, there are two silicone tubes (inlet and outlet) with an outer diameter of 3 mm connecting to the SSA. Figure 2. Structure of the silicone SSAs with mechanical connections and electrical connections. 2.3. Design of the Gripper Jaw with Stiffness Control The finger shown in Figure 3a was inspired by a surgical robot that can change its joint stiffness [32]. The finger was 3D-printed using polylactic acid (PLA) and had revolute joints linking the entire finger, with each finger actuated by two tendons. Figure 3a,b illustrate the robot link\u2019s structure with two linkages and a rotational joint. To increase the grasping ability of the tendon-driven gripper, a silicone pad is attached to the end effector linkage" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003053_f_version_1614169697-Figure5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003053_f_version_1614169697-Figure5-1.png", + "caption": "Figure 5. Kinematic scheme of the proposed foot mechanism based on the corresponding points (A to E) in the foot mobility diagram in Figure 4: (1) hindfoot; (2) midfoot; (3) forefoot; (4) compliant body.", + "texts": [ + " The plantar fascia and several ligaments support the plantar arches, which store mechanical energy during weight bearing by deforming. This behavior can be reproduced with the elasticity of a compliant body. The motion of the last segment of the foot can be approximated to a flexion/extension movement of the toes, which rotate around the MTP joint and the interphalangeal joints. The MTP joint is usually described as a condyloid joint, while the interphalangeal joints resemble revolute joints. In order to replicate the behavior of the human foot, a new compliant foot mechanism based on the kinematic scheme in Figure 5 is here presented. The proposed mechanism is based on a compliant mechanism in the plant, which can be approximated with an RRPR (revolute-revolute-prismatic-revolute) architecture, with revolute joints in points B, C, and D, and a link of varying length between B and D. Furthermore, a second compliant mechanism is added in the MTP joint in point E, with a rigid revolute joint controlled by a torsional spring. The mechanism works mainly on the sagittal plane, even if the compliant part can be designed to balance 3D loads as well" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003551_8600701_08941328.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003551_8600701_08941328.pdf-Figure1-1.png", + "caption": "FIGURE 1. The schematic diagram of the experimental system.", + "texts": [ + " Section III is about the algorithm framework of this paper. Section IV describes the global rough seam extraction. Section V describes the local fine positioning of weld seam. Section VI introduces the experimental analysis. Finally, the conclusions and prospects are summarized. II. SYSTEM CONFIGURATION AND SYSTEM ARCHITECTURE A. EXPERIMENT PLATFORM Here, an intelligent welding robot platform is designed to verify the performance of the proposed algorithm. The special system framework of the the experimental platform is shown in Fig.1. It mainly includes two parts: industrial robot platform and vision sensor. The industrial robot platform includes manipulator, teaching box, welding work pieces and manipulator controller. The vision system is used to perceive the global weld seam which is made up by industrial camera, optical projector and vision computer. To construct the experimental platform, the Motoman UP6manipulator is designed the welding robot platform. The high-performance industrial camera of MER-500-7UC with 2592(H)\u00d71944(V) resolution is adopted to design the vision sensor" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004136_f_version_1656584453-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004136_f_version_1656584453-Figure3-1.png", + "caption": "Figure 3. Motion deviation of the pusher robot.", + "texts": [ + " \u03b8 = r 2 cos \u03b8 r 2 sin \u03b8 \u2212 r L r 2 cos \u03b8 r 2 sin \u03b8 r L \u00b7 \u03c9l \u03c9r (7) It can be seen from Formula (7) that the pose state of the robot at each moment was obtained by using the angular velocity of the driving wheels on both sides of the robot at the corresponding moment. 2.2.2. Motion Control The lateral deviation and angular deviation of the robot was obtained through the fitting of the cowshed fence, the extraction of the operation route and the determination of the robot\u2019s pose state [19]. The motion deviation of the pusher robot is shown in Figure 3. During the working process of the pusher robot, the linear speed was related to the angle deviation. When there was no angular deviation, the actual line speed moved according to the set line speed; when there was an angular deviation, within a certain range, the larger the angle deviation, the smaller the actual line speed should be, so as to avoid the robot deviating further and further away. The actual angular velocity was related to lateral deviation and heading deviation [20]. When there was lateral deviation or angular deviation, the mobile robot would generate a corresponding angular velocity to eliminate the deviation; when both the lateral deviation and the angular deviation were zero, the actual angular velocity of the mobile robot was zero" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002984_0.1145_218380.218498-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002984_0.1145_218380.218498-Figure1-1.png", + "caption": "Figure 1: Geometry for the reflectance equation.", + "texts": [ + " We have chosen two basic problems in rendering to illustrate our techniques: evaluation of the radiance leaving a surface given a description of the incoming illumination (as in distribution ray tracing or some \u201cfinal gather\u201d approaches), and direct solution of the rendering equation[5]. For further details and background see [3]. Given the incident radiance distribution Li(x0; ~!0i ) at a point x0 , 9 the reflected radianceLr(x0; ~!0r) is given by the reflectanceequation Lr(x 0 ; ~! 0 r) = Z S 2 fr(x 0 ; ~! 0 i$~! 0 r)Li(x; ~! 0 i) cos( 0i) d (~!0i) (1) where fr is the bidirectional reflectance distribution function (BRDF), S2 is the set of all unit direction vectors, is the usual solid angle measure, and 0i is the angle between ~!0i and the surface normal at x0 (see Fig. 1). We allow fr to model transmission as well (in this case fr is the bidirectional scattering distribution function). Sometimes it is preferable to express the reflectance equation as an integral over the domain M of scene surfaces (e.g. for direct lighting calculations). This form is given by Lr(x 0 !x 00 ) = Z M fr(x$x 0 $x 00 )G(x$x 0 )Li(x!x 0 )dA(x) (2) where G(x$x 0 ) = V (x$x 0 ) cos( r) cos( 0 i) kx x 0k2 : Here A is the usual measure of surface area, r and 0 i measure the angle between x$ x 0 and the surface normals at x and x 0 respectively, while V (x$x 0 ) is 1 if x and x0 are mutually visible and 0 otherwise", + " a small bright light, or a shiny surface), that sampling technique will do poorly. It is important to realize that both strategies are importance sampling techniques aimed at generating sample points on the same domain (in this case, the light source S). Area sampling chooses a point x 2 S directly, while directional sampling choosesx by casting a ray in the chosen direction ~!0i . Given a directional distribution p(~! 0 i) d (~! 0 i), the corresponding area distribution p(x) dA(x) is p(x) = p(~! 0 i ) d (~! 0 i) dA(x) = p(~! 0 i ) cos( r) kx x 0k2 : (9) (see Fig. 1)1 . This lets us compute the probability densities assigned by area and directional methods to the same point x. When choosing a Monte Carlo sampling technique, we rarely know exactly what the integrand is. Instead, we have some model for the integrand, defined by a set of parameters (e.g. the BRDF, the scene geometry, etc). Given several sampling techniques to choose from, the variance of each one can change dramatically as these parameters vary. Our main goal is to show how Monte Carlo integration can be made more robust, by constructing estimators that have low variance for a broad class of integrands" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004136_f_version_1656584453-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004136_f_version_1656584453-Figure2-1.png", + "caption": "Figure 2. Kinematics model of the pusher robot.", + "texts": [ + " During steering control, steering was achieved by changing the speed difference of the servo motors on both sides used to drive the wheels. The differences between the servo motor speeds caused the vehicle to deviate from the desired direction, and the yaw angle varied ith the magnitude of the speed difference. Likewise, if the speed of the servo motors on both sides was equal, there would be no direction change. The robot could keep driving in a straight line without lateral deviation. 2.2.1. Motion Modeling Without considering the slippage and sideslip of the crawler car [16], the motion model of the robot is shown in Figure 2. Firstly, we established the world coordinate system XwOYw: Xw represented the horizontal direction, O represented the origin of the world coordinate system, and Yw represented the direction perpendicular to the Xw axis. Then, the kinematics model of the pusher robot was established in the coordinate system. The rectangle represented the chassis of the robot, the two small black squares represented the two driving wheels of the robot, and the circle inside the rectangle represented a universal wheel", + " \u03b8 was the angle between the forward direction of the robot [17] and the world coordinate system Xw, which represented the pose angle of the robot. vl, vr, wl, and wr Appl. Sci. 2022, 12, 6641 5 of 23 represented the linear and angular velocities of the left and right wheels. v, w, and OC represented the instantaneous velocity, angular velocity and instantaneous center of the robot motion, respectively. Appl. Sci. 2022, 12, x FOR PEER REVIEW 5 of 28 2.2.1. Motion Modeling Without considering the slippage and sideslip of the crawler car [16], the motion model of the robot is shown in Figure 2. Firstly, we established the world coordinate system XwOYw: Xw represented the horizontal direction, O represented the origin of the world coordinate system, and Yw represented the direction perpendicular to the Xw axis. Then, the kinematics model of the pusher robot was established in the coordinate system. The rectangle represented the chassis of the robot, the two small black squares represented the two driving wheels of the robot, and the circle inside the rectangle represented a universal wheel" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002867_9312710_09367135.pdf-Figure1-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002867_9312710_09367135.pdf-Figure1-1.png", + "caption": "FIGURE 1. Kinematic structure of the UVMS team.", + "texts": [ + " (4) The position and attitude of the arm, with respect to the 0\u2212frame located at its base, can be represented with the pose vector: 0\u03b7n = [0\u03b70n1 T 0\u03b70n2 T ]T = [x0n y0n z0n \u03c60n \u03b80n \u03c80n]T (5) which can be computed from the arm configuration vector (q) computing the forward kinematics of the arm [21]: 0An(q) = n\u220f i=1 i\u22121Ai(qi) = [ 0Rn(0\u03b70n2 ) 0\u03b70n1 01\u00d73 1 ] (6) where i\u22121Ai(qi) are the link to link transformation matrices depending on the DH parameters. The Euler angles of the arm (\u03b70n2 = [\u03c60n \u03b80n \u03c80n]T ) can be obtained from: 0Rn(0\u03b70n2 ) = Rz,\u03c80nRy,\u03b80nRx,\u03c60n (7) solving for \u03c60n, \u03b80n and \u03c80n. Therefore, given the UVMS generalized coordinates q, its end-effector pose: \u03b7ee = [\u03b7ee1 \u03b7ee2 ] T = [xee yee zee \u03c6ee \u03b8ee \u03c8ee]T (8) defined with respect to N\u2212frame, depends on the AUV pose \u03b7 and the end-effector pose 0\u03b70n (Fig. 1). The UVMS pose, can also be expressed as a homogeneous matrix: NKn(q) = NKB(\u03b7) \u00b7B H0 \u00b7 0 An(q) = [ NRn(\u03b7ee2 ) \u03b7ee1 01\u00d73 1 ] . (9) where BH0 is the transformation matrix from the B\u2212frame to the 0\u2212frame. C. KINEMATICS OF VELOCITY The UVMS Jacobian [22] relates the quasi-velocities \u03b6 = [\u03bdT q\u0307T ]T to the end-effector rate of change \u03b7\u0307ee : \u03b7\u0307ee = J (q)\u03b6 (10) being \u03bd = [\u03bd1T \u03bd2T ]T = [u v w p q r]T the AUV linear and angular velocity vector. Given the AUV Jacobian: \u03b7\u0307 = J\u03bd(\u03b7)\u03bd J\u03bd(\u03b7) = [ NRB(\u03b72) 03\u00d73 03\u00d73 J\u03bd2 (\u03b72) ] , (11) where J\u03bd2 (\u03b72) is the matrix mapping the angular velocity into the Euler angle rates, and given the arm geometric Jacobian:[0\u03b7\u03070n1 0\u03bd0n2 ] = Jm(q)q\u0307 Jm(q) = [ Jm,p(q) Jm,o(q) ] Jm,p(q) = \u2202\u03b70n1 \u2202q Jmo (q) = \u2202\u03bd0n2 \u2202q , (12) 37670 VOLUME 9, 2021 the UVMS geometric Jacobian J (10) can be computed as follows: [ \u03b7\u0307ee1 \u03bdee2 ] = [ Jp(q) Jo(q) ] [ \u03bd q\u0307 ] = J (q)\u03b6 (13) where Jp(q) = [ NRB \u2212HNRB Jm,p(q) ] H = [NRBBrB0]\u00d7 + [NR00\u03b70,ee]\u00d7 (14) and Jo(q) = [ 03\u00d73 NRB Jm,o(q) ] , (15) being [a]\u00d7 the skew symmetric matrix so that c = a \u00d7 b = [a]\u00d7b", + " PLATFORMS The team of robots consists of two GIRONA500 lightweight, modular I-AUVs designed and developed at the University of Girona [26], which can be reconfigured for different tasks by changing their payload and thruster configuration. Each vehicle was used in a 4 DOF configuration (yaw, surge, sway and heave), being passively stable in pitch and roll by design. The manipulators employed are an ECA 5E Micro and an ECA 5E Mini, both with four rotational joints actuated by electric screw drives, which makes them powerful but slow. Nevertheless, the drives exhibit high friction forces resulting in a velocity dead-band zone. The kinematic structure of both UVMSs is presented in Fig. 1. In order to correctly grasp the pipe, a custom end-effector has been designed and built (see Algorithm 1: Adaptive Scaling of the Desired EEs Velocity Fig. 6). The shape of the fingers helps to drive the pipe to the end-effector center. Additionally, three cameras are being used for each robot: 1) An analog camera attached to the body of the GIRONA500, which is forward-looking, and is used to localize the pipe based on the detection of ARUCO markers [27]; 2) An analog camera embedded in the end-effector, used to provide visual feedback to improve the grasping accuracy, and 3) A high-performance megapixel down-looking industrial camera, attached to the lower side of the I-AUV, used for getting seafloor image updates for the navigation filter" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001696_f_version_1624521986-Figure3-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001696_f_version_1624521986-Figure3-1.png", + "caption": "Figure 3. Description of the Cartesian coordinate system from the Mecanum wheel and symmetrical OMR chassis with four Mecanum wheels (all conventions are in concordance with the right-handed Cartesian coordinate system and representation of the wheel in 2D space is judged in terms of wheel tracks left on ground).", + "texts": [ + " The platform used in this study consists of four Mecanum wheels driven by individual motors and has important capabilities, especially for industrial environments, as it is able to move in any direction whilst spinning around its vertical axis. In order to minimize the vibrations caused by the spacers between rollers which affect the stability, the platform is provided with suspension mechanism based on traditional dampers. The robot was completely set up for autonomous navigation utilizing ROS, camera and a 360\u00b0 LiDAR. Figure 3 presents the geometrical model of the OMR prototype with the coordinates system assignments to each wheel, platform configuration, and all variables necessary for developing the kinematic model. As described at the beginning of Section 3, the control system deals with two kinematic transformations: the forward model which uses the speeds of all wheels to determine the relative speed of the platform, while the inverse kinematic model takes the components of the decomposed relative speed of the platform in order to obtain the required speed for each wheel", + " The resulting velocity vector v is determined by instantaneous translation velocities of the robot (vx respectively vy) in the coordinate system of chassis OXYZ. The position of each wheel i is uniquely determined in relation to the distance considered as a vector (thus having a sign depending on the direction of the axis to which it refers) as well as rotation angle between the wheel frame and roller frame (for a Mecanum wheel this angle is equal \u00b145\u00b0). In concordance with notations from Table 1 the particularized symmetric values for the structural parameters from Figure 3 are presented in Table 2. Therefore the impact of the linear velocity vector (vi) of the wheel i and the velocity of the roller in contact with the ground (vgi ) on the velocity vector of the robot can be calculated [26\u201328] by: vi + vgi cos(\u03b3i) = vx \u2212 lyi \u2126 (3) vgi sin(\u03b3i) = vy + lxi \u2126 (4) Because vgi is an uncontrollable variable of the passive roller, it will be eliminated through substitution from Equations (3) and (4): vi = vx \u2212 lyi \u2126 \u2212 1 tan(\u03b3i) (vy + lxi \u2126) (5) By customizing the parameters from Table 2 for each wheel and transforming linear velocity of each wheel to angular wheel velocity (vi = R\u03c9i), the wheels speed equations can be written as: R\u03c91 = vx + vy \u2212 (lx + ly)\u2126 R\u03c92 = vx \u2212 vy \u2212 (lx + ly)\u2126 R\u03c93 = vx + vy + (lx + ly)\u2126 R\u03c94 = vx \u2212 vy + (lx + ly)\u2126 (6) The matrix representation, which is the most used method for inverse kinematics calculations, is presented in Equation (7): \u03c91 \u03c92 \u03c93 \u03c94 = 1 R 1 1 \u2212(lx + ly) 1 \u22121 \u2212(lx + ly) 1 1 (lx + ly) 1 \u22121 (lx + ly) vx vy \u2126 (7) The inverse kinematic Jacobian matrix J of the OMR is expressed as: J = 1 R 1 1 \u2212(lx + ly) 1 \u22121 \u2212(lx + ly) 1 1 (lx + ly) 1 \u22121 (lx + ly) (8) In order to obtain the forward kinematic equations, used for calculating the linear and angular speeds of OMR relative to the ground, the deduction starts from Jacobian matrix, which has 4 \u00d7 3 dimensions, it must be used a pseudo inverse matrix J+ such that J+ \u00b7 J = I3, which it is determined with the formula from [27]: J+ = (JT \u00b7 J)\u22121 \u00b7 JT (9) The values calculated for OMR with conventional notations from Table 2 for forward kinematics are: J+ = R 4 1 1 1 1 1 \u22121 1 \u22121 \u2212(lx + ly)\u22121 \u2212(lx + ly)\u22121 (lx + ly)\u22121 (lx + ly)\u22121 (10) And the resultant direct kinematics transformation representing linear and angular velocities of the OMR relative to ground is: vx vy \u2126 = J+ \u03c91 \u03c92 \u03c93 \u03c94 (11) The matrix equations Equations (7) and (11) are essential components of the vehicle controller firmware implementation that is presented in Section 3" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001316_f_version_1704977152-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001316_f_version_1704977152-Figure4-1.png", + "caption": "Figure 4. Gripper assembly. Subassembly A is the rigid body anchoring the gripper and encasing the vacuum filter. Subassembly B is the soft body described in this publication. We provide further details about the entire assembly in the Supplementary Materials section.", + "texts": [ + " Although this behavior might be considered beneficial in certain scenarios, this study opts to analyze the different filler sizes separately. To confirm this, a sampling of the glass balls was performed under a microscope (Figure 3) to verify that the dimensions of the glass beads indeed matched the manufacturer\u2019s specifications. While it is true that some beads of different size might appear, their population density was not very notable, thus leaving the effects of polydispersity outside the scope of this work. As shown in Figure 4, two subassemblies comprise the prototype: the rigid support and the deformable body. At the top is the rigid support, which anchors the gripper to the robot or the tensile tester. In addition, the rigid support includes the necessary components to guarantee the hermetic sealing of the deformable body and the vacuum filter. We include a detailed exploded-view assembly drawing as supplementary material. On the other hand, the soft body comprises the two elements relevant to this research: the envelope and the granulate material", + " This parameter is the area between the tensile curve and the final traction value derived from the prototype\u2019s weight (F3). \u2022 Deformation force (F2). This value is equal to the difference between the weight (F3) and the initial value of the tensile curve. Figure 9 also shows two other complementary parameters: \u2022 Gripping distance (d). This parameter shows the distance over which the prototype can grip the mushroom-shaped specimen along its frictional spherical zone (Figure 7A). \u2022 Total weight of the prototype (F3). This value includes the weight of the assembly shown in Figure 4 plus other components that attach it to the tensile tester. As stated in the methodology, the material combinations result in a four-row by fourcolumn matrix. Every element in the matrix gathers five experiments. Figure 8 shows the outcomes of the pull-off force test in the following arrangement: ball particle diameters increase from left to right, while envelope pliability increases from bottom to top. The three relevant parameters to assess the material combinations emerge from these plots, and the following lines discuss them individually" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0000428_0120959_WLA_0086.pdf-Figure1-2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000428_0120959_WLA_0086.pdf-Figure1-2-1.png", + "caption": "Figure 1-2 Illustration of different categories of drone. (a1 - a2) Fixed wing drones of eBee [9]", + "texts": [ + " After that, the quadrotors drew little attention until the 1990s. Since the mid-1990s, the small UAV had a greater and larger development due to the advancement of technology, and the interest drawing from military and commerce [5]. Furthermore, nowadays the drone realizes a more fast and extensive development because of its vast potentiality in application, which has been mainly developed and formed into three different prototypes in the UAV or MAV [1,6-9], being categorized to be the fixed wing drone (Figure 1-2a) [9-14], the rotary wing drone (Figure 1-2b) [8,9,15-19], and the flapping wing drone (Figure 1-2c) [9,20-24]. Moreover, bioinspired by the flight performance of birds and insects, some creative drones or function integrated drones are also designed and tested, such as the drone with flexible or foldable wings (Figure 1-3a) [25-29], the drone with collision resilient structures (Figure 1-3b) [30,31], the drone with integrated functions of walking and flying (Figure Chapter 1.1 Introduction of drone 2 1-3c) [32,33] and so on. Considering the windy or gusty condition outdoors, hovering capability indoors, endurance in hovering and frame size, the rotary wing drone may be a more practical and valuable option for the majority of missions due to its hover and flight capabilities [1,8]" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003861_rotor-3n2t18d2ak.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003861_rotor-3n2t18d2ak.pdf-Figure2-1.png", + "caption": "Fig. 2. 3D model of the turbine rotor", + "texts": [ + " It is absolutely necessary to ensure durable components [11]. Equally important here is to regularly check the operating temperature, which was highlighted in the paper [12]. Energetic turbines' dynamic properties, as described in the article [10], are strongly influenced by residual unbalance [13] and axial forces acting on the turbine stage(s). The nominal speed of the designed five-stage turbine is 3000 rpm. The turbine shaft was made of 40 HM constructional steel and it weighs about 240 kg. Fig. 2 shows the turbine rotor model created by means of FEM (Finite Element Method). The radial bearings mounting points are indicated by the two arrows. The numerical analyses were carried out using MADYN 2000 (commercial software) and KINWIR-I, NLDW in-house developed computer programs included in the MESWIR system. This system was developed at the IFFM PAS in Gda\u0144sk. The model created in Madyn 2000 is presented in Fig. 3, it comprised 52 beam elements. The shaft length was 1.646 m. The distance between the two journal bearings was 1" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002923_f_version_1606874132-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002923_f_version_1606874132-Figure4-1.png", + "caption": "Figure 4. Building a convex obstacle outline.", + "texts": [ + " Step 1: If sequence Qin consists of less than 3 points, mark these points for further inclusion in the output sequence Qout and go to Step 5. Step 2: Mark the start and end points of Qin. Assign i0 = 1. Step 3: By going through the points, starting from point Qi0 , find the first point Qik that satisfies the following condition: there exists a point Qi between Qi0 and Qik such that the shortest distance from it to the line passing through the points Qi0 and Qik is greater than a predetermined value Dm and it lies on the same side of the line as the AUV (see Figure 4). If such a point does not exist, go to Step 5. Step 4: Mark the point Qik\u22121 immediately preceding point Qik . If Qik is not the end point of Qin, then i0 = ik \u2212 1 and go to Step 3. Step 5: Form the sequence Qout from all marked points of Qin keeping the order. Note that the proposed algorithm is robust in the sense that small measurement errors and the irregularity of the obstacle do not significantly increase the number of generated points. When using the resulting convex outline in the path-planning algorithm presented in the next section, the safe distance parameter Ds should be increased by Dm" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002374__issue-pdf_14110.pdf-Figure6-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002374__issue-pdf_14110.pdf-Figure6-1.png", + "caption": "Figure 6. Robot prototype design with pneumatic actuation for upper limb rehabilitation", + "texts": [ + " Figures 5 and 6 show the simple design of a pneumatically driven robotic workbench for rehabilitation of upper and lower limbs that it was designed on CAD (Computer Aided Design) software. each mechanism joint is performed by a pneumatic servo positioner comprising a double-acting cylinder and simple rod, and a five-way directional servo valve. Figure 7 presents the representation of the pneumatic scheme of the robot, designed according to ISO 1219 2012). Table 1 describes the basic elements of the pneumatic robot drive system, according to the numerical indication of the Figure 6. For each limb i (upper or lower) to be exercised with an angular movement i of the mechanism, it is necessary to apply a load force fLi provided by the pneumatic system. The mechanical system of the robotic workbench is shown in Figure 4, where the main loads and parameters involved in each limb rotation dynamics are gravity torque fLi, the moment of inertia I0i of the rotating mass (mechanism and limb) around the rotation axis, the angular acceleration of the platform and the distance r from the turning center to the point of application of the force" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002463_icmite2017_00210.pdf-Figure4-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002463_icmite2017_00210.pdf-Figure4-1.png", + "caption": "Figure 4. Structure design of horizontal movement platform Two drive wheels are mounted on both sides of the front bogie, and two driven wheels are mounted on both sides of the rear bogie. The driving force of the robot movement comes from the friction between the driving wheel and the track surface. The drive wheel is driven by a DC servo motor.", + "texts": [], + "surrounding_texts": [ + "The basic movement of the robot is divided into horizontal movement and lifting movement. In order to meet the precise identification requirements, the positioning error of each direction should be control within 5mm. There are two ways chosen to achieve the positioning of horizontal movement. The RFID installed on the side of the track is used for absolute positioning\uff0cand the number of pulses emitted by DC servo motor driver is used for incremental positioning. In autorun mode, the location information sent by the host computer contains the RFID position and the number of pulses which are given by the debugging staff in site. This combined positioning method reduced positioning error compared with the relative positioning method\uff0c and improved positioning accuracy in the case of cost reduction. A proximity switch mounted at the top of the lifting mechanism plays a role of the zero position in the vertical direction. The number of pulses emitted by DC servo motor driver is used to make the positioning of vertical movement. The number of pulses is proportional to the lift distance. The lift stroke is 2m, so the cumulative error of the lift movement is very small and. Vertical positioning error actual measured is less than 2mm when the robot runs at the speed of 0.1m/s in the vertical direction. The inspection robot will call the PTZ preset position after the robot reaches the specified position to complete the detection work, or call the PD detection component to perform the partial discharge detection task." + ] + }, + { + "image_filename": "designv7_3_0000377_9359896_09311188.pdf-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0000377_9359896_09311188.pdf-Figure2-1.png", + "caption": "Fig. 2. Symmetric linear actuator configuration in the sagittal plane on the right leg. Actuator forces acting on the exoskeleton structure in blue.", + "texts": [ + " Analysis showed that the highest range of motion is found in the knee joint (about 65\u25e6) as well as the highest velocity and acceleration. The torque profile of the knee (for an 80 kg subject) is similar to the hip, where the ankle joint has a three times higher torque during stance. The torque profile for the ankle is mostly unidirectional, while the knee and hip joints require both positive and negative torques. The frequency content of gait motions and torques is up to about 4 Hz and is directly proportional to the walking speed. Placement of the actuators was symmetric with respect to the joint and as shown in Figure 2. The actuator locations were chosen such that pushing actuator forces (actuator in compression) deliver the maximum joint torques to make use of the high forces hydraulics can deliver. Note that actuator elongation corresponds to a negative joint angle, so positive actuator motion and force corresponds to extension of the hip and knee joint and plantar flexion for the ankle. The configuration parameters (h and d) were estimated based on the size of small commercially available cylinders (see Experimental Setup section). Translating the joint requirements to the actuators resulted in similar observations as done by analysis of gait data. The large range of motion of the knee joint now resulted in a significantly higher actuator velocity for the chosen configuration. The actuator requirements for the three joints for the given configuration are shown in Table I, split in swing and stance gait phases. The average moment arms (over a gait cycle, using the configuration shown in Figure 2) were 107 (75 to 130), 110 (60 to 185) and 61 (35 to 74) mm for the hip, knee and ankle joint actuators, respectively. Placing the actuator closer to the joint reduced the required velocity and would be more favorable for hydraulic cylinders. In this work, the size of the commercial cylinders prevented a more favorable configuration. From these requirements the large stroke of the knee actuator demands high dynamic performance, especially during swing, which complicated the design. The high force of the ankle is less of a challenge, since hydraulic actuators are well suited to deliver high forces in less dynamic conditions (during stance)", + " In other words; the series elastic spring compression (and thus output force Fout) is caused on one hand by the output cylinder motion (contained in the PREHydrA block) and on the other hand by the pendulum motion. Calculating the spring deflection on the pendulum side is a nonlinear function of the pendulum angle, since it is the anti-derivative of the moment arm. A trigonometric function gives the moment arm: r(\u03b8p) = \u221a h2 knee + d2 knee sin ( tan\u22121 ( dknee hknee ) + 20\u03c0/180 \u2212 \u03b8p 2 ) In which the moment arm is calculated from the configuration parameters, hknee and dknee (as shown in Figure 2) in m and the pendulum angle \u03b8p in rad. This is derived from a straightforward trigonometric analysis of the knee joint. Note the 20\u25e6 offset between pendulum angle, \u03b8p, and knee angle (\u03b8knee = 20 \u2212 \u03b8p), that matches the pendulum orientation with that of a leg in swing. This is shown in Figure 7. The moment arm is also multiplied by the output force to find the torque acting on the pendulum, so this geometric nonlinearity is introduced twice in the system; from PREHydrA to pendulum block and back" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003495_f_version_1665659211-Figure2-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003495_f_version_1665659211-Figure2-1.png", + "caption": "Figure 2. The omni-directional wheeled mobile robot from the top view.", + "texts": [ + " In this section, mathematical models will be established for the actuation subsystem and each inverted pendulum subsystem and finally, from the system model of the mobile robot, the forces and torque generated by the mobile robot for controlling the inverted pendulum subsystems are given in terms of the motor control voltages. Here is a mathematical model derived for an omni-directional wheeled mobile robot using Newton\u2019s laws [24]. This mobile robot consists of a rigid circular chassis and three omni-directional wheels labeled 1, 2, and 3. The wheels were arranged at an equal distance from the center of the robot chassis and equally spaced at 120\u25e6. All wheels are assumed to roll without slip. Figure 2 illustrates the basic features of an omni-directional wheeled mobile robot from the top view. The system variables and parameters are defined as below: O\u0302W , X\u0302W , Y\u0302W : world coordinate system. O\u0302M, X\u0302M, Y\u0302M : body coordinate system with the origin attached to the center of mass of the mobile robot, and the Y\u0302M-axis is aligned to wheel 1. Mt : mass of the mobile robot with the pendulum. f1, f2, f3 : reaction force applied by the ground to the omni-directional wheel, where the direction is vertical to wheel axes 1, 2, and 3, respectively" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004481_20_c5_ibarra2020.pdf-Figure16-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004481_20_c5_ibarra2020.pdf-Figure16-1.png", + "caption": "Fig. 16. Design and 3D printing of the remote control box", + "texts": [ + " The arduino development board is in charge of commanding the previously recorded sentences to govern the entire system through wireless communication or in response to the sensor signal, the inputs and outputs are assigned, all the selected components and elements are installed on a board base where the plates of each component that were explained above are inserted, establishing a modular design that will facilitate maintenance and repair if the robot needs it in the future. Once the simulations were completed, the double-sided board was manufactured (figure 15), the elements were soldered with a tin wire, the surface elements were soldered with liquid tin, for the arduino and the Xbee, spade connectors were soldered to They are removable, in addition the two control Hbridges for the motors that make the robot go up and down the steps were welded. The board has five drilled holes for fixing to the robot chassis. To carry out the design of the control box (Figure 16) for remote control, the material for its manufacture was selected through a decision table with a weighting of characteristics where the material selected was PLA plastic, the price is high, but it has a long useful life, it is light and it is also easy to use.The design was made with the help of CAD software, it was manufactured by 3D printing and included holes for the connection of external elements such as antenna, joystick, viewfinder , among others. Internally, it has sections to locate electronic boards for teleoperation and transmission of video signals" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0001682_f_version_1566814295-Figure21-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001682_f_version_1566814295-Figure21-1.png", + "caption": "Figure 21. Physical implementation of the soft epicyclical tendon-driven actuation system based on SMA.", + "texts": [ + " During the operation, when the tendon is under a tension FT , a control stimulus (temperature increment) shifts the SMA wire to austenite phase, increasing the stiffness to recover the produced strain. Consequently, the soft epicyclical tendon-driven actuation system based on SMA has been implemented, placing a wire of SMA in parallel with a Nylon wire. The used shape memory alloy wire is a FLEXINOL c\u00a9 actuator\u2014which is a trade name for nickel\u2013titanium SMA wires\u2014with 0.38 mm diameter, bought at Dynallow Inc. [34]. Figure 21 shows the implementation in the new robotic finger. Preliminary tests have shown that the substitution of the damper element by an SMA wire can reduce or eliminate the overshoot of dependent joint angles. Analytically, it can be seen that a variable stiffness element, in parallel with an elastic element, can handle global stiffness of the mechanism and render it adaptable to several grasping situations. On the other hand, the transient state of the system can be changed from a critically-damped to an over-damped behavior" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003007_d-Sutherland-PhD.pdf-FigureC-24-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003007_d-Sutherland-PhD.pdf-FigureC-24-1.png", + "caption": "Figure C-24 Free body diagram for link \u201c2\u201d. Torque and force acting at point \u201cC\u201d appear to work in the opposite direction to that experienced by link 3.", + "texts": [ + " From (27) and (25): \u03b8 ~~~ 333 &&Cmff D \u2212= \u03b8\u03b8 ~~ ~00 ~00~ 333 &&&& L L Cm f f f Dy Dx \u2212 = (28) Equation (28) can be rearranged to express 3 ~f as a matrix (of known element values), multiplied by \u03b8 ~ && : \u03b8 ~~ 33 &&Ff = (29) Next, the free body diagram of link 3, shown in Figure C-23, is used to determine the effects of the linear forces on the resultant torque acting through the link centre of mass: 386 \u2211= \u03c4\u03c4 )3(com )(~)(~)(~)(~ 333)3( comCyDcomDxcomCxDcomDyDcom xxfyyfyyfxxf \u2212\u2212\u2212\u2212\u2212+\u2212++= \u03c4\u03c4\u03c4 (30) Substituting (26) \u2192 (30): )(~)(~)(~)(~ 33333 comCyDcomDxcomCxDcomDyD xxfyyfyyfxxfI \u2212\u2212\u2212\u2212\u2212+\u2212++= \u03c4\u03c4\u03b8&& (31) Using (29), equation (31) can be rearranged to the form: \u03b8\u03c4 ~~ 33 &&c= (32) Where: 387 )3(com\u03c4 Resultant force appearing to act through the centre of mass of link 3. D\u03c4 External torque being applied to the end of link 3 (at point \u201cD\u201d). Note: for link 3, this torque is zero. 3\u03c4 Torque being applied to the base of link 3. 3 ~c Vector of known (n+3) elements, relating 3\u03c4 to \u03b8 ~ && . 3 ~f Force acting on the base of link 3. Df~ Force acting on the end of link 3. This process can now be repeated for the next link, moving inwards towards the robot base, chosen in step (i). The free body diagram for link 2 is shown in Figure C-24: Using the same process outlined for link 3, force and torque acting on the base of link 2 can be expressed by equations (33) and (34). Force acting on the base of link 2: \u03b8 ~~ 22 &&Ff = (33) 388 Torque applied to base of link 2: \u03b8\u03c4 ~~ 22 &&c= (34) This process of \u201cinward iteration\u201d can be continued all the way back to the base of the robot system, with one small variation for the case where multiple branches of the robot link tree converge. In this situation, the iterative inward calculations of force and torque must be performed on each branch of the tree of robot links" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004679_f_version_1695908635-Figure14-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004679_f_version_1695908635-Figure14-1.png", + "caption": "Figure 14. Intelligent agricultural machinery real vehicle test platform.", + "texts": [ + "029 m, and the maximum error in the Y-axis direction is 0.049 m, with an average error of 0.031 m. The simulation test results show that the improved pure pursuit algorithm proposed in this paper has high control accuracy and can be applied to agricultural machinery motion control. To further validate the performance of the positioning, planning, and motion control algorithms in this article, an intelligent agricultural machinery real vehicle test platform was built based on an electric tracked chassis, as shown in Figure 14. This real vehicle testing platform is equipped with sensors such as binocular cameras, LiDAR, RTK/INS integrated navigation, etc. The perception information of each sensor is received through the onboard computing platform, which can be used for the real vehicle verification of various algorithms in the field of intelligent agricultural machinery. The main equipment parameters of the actual vehicle test platform are shown in Table 1. As shown in Figure 15, an open field was selected to validate the full-coverage path planning algorithm and improved pure pursuit algorithm proposed in this paper on a real vehicle" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0002763_eu_1611_fulltext.pdf-Figure97-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0002763_eu_1611_fulltext.pdf-Figure97-1.png", + "caption": "Figure 97: Cross-section view of the linear ERF actuator. The ER fluid flows between the stationary electrodes forming the valve. The pressure drop across the valve can be controlled by varying the electric field strength between the electrodes; thus forming a pressure control valve.", + "texts": [ + " These valves work on a differential pressure principle: When system pressure reaches the set value, a pilot cone acting against a spring lifts slightly off its seat. The resulting pilot flow passes through a small control orifice in the main poppet, causing a pressure differential which lifts the main poppet off its seat. When the main poppet is unseated, flow is bypassed to tank and the desired system pressure is maintained.............................................................................................................................. 108 Figure 97: Cross-section view of the linear ERF actuator. The ER fluid flows between the stationary electrodes forming the valve. The pressure drop across the valve can be controlled by varying the electric field strength between the electrodes; thus forming a pressure control valve. ........................................................................................................... 109 Figure 98: The hydraulic gear pump (LEFT) driven by a DC motor (RIGHT) provides the flow that actuates the system", + " In contrast, the pressure of an ERF actuator is controlled right inside the cylinder via a built-in smart valve with no moving parts. This allows fine force/torque control with high bandwidth thanks to the high response rate of ERFs and the proximity of the control valve to the piston. 109 lifts the main poppet off its seat. When the main poppet is unseated, flow is bypassed to tank and the desired system pressure is maintained. The ERF valve of the linear actuator is comprised of three concentric aluminum tubes that form two annular gaps through which the ER fluid can flow (Figure 97). The aluminum tubes also serve as electrodes that generate an electric field when subjected to a high voltage potential. When an electrical potential is applied to the electrodes, the resultant electric field across the gap causes a rapid change in the yield stress of the ER fluid. The pressure drop across the length of the valve can be controlled by modulating the strength of the field. Thus, the annular gap works like a pressure control valve that is integrated into the cylinder. 110 The description in the preceding paragraphs also explains the operation of ERF dampers" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure35-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0003741_tr_pdf_AD1071197.pdf-Figure35-1.png", + "caption": "Figure 35. Physical principle of EI.", + "texts": [ + "1 Existing technologies for miter gate anti-corrosion thickness assessment of non-metallic coatings Four different sensor technologies were investigated to ascertain the most appropriate design for determining the thickness of the anti-corrosion coating on the upstream side of a miter gate: (1) Electromagnetic Induction, (2) Ultrasonic Pulse-Echo, (3) Low-Coherence Interferometry, and (4) Magnetic Pull-Off. The Electromagnetic Induction (EI) technique measures the change in magnetic flux density at the surface of a magnetic probe as it nears a steel surface (Figure 35). The magnitude of the magnetic flux density at the probe surface is inversely proportional to the square of the distance from the steel substrate. Therefore, by placing the probe directly on the nonconductive coating, the magnitude of the flux density at the probe surface corresponds to the thickness of the anti-corrosion coating. EI testing for coating thickness measurement is one of the most-accepted methodologies in industry today, and many relatively low-cost EI sensors are commercially available" + ], + "surrounding_texts": [] + }, + { + "image_filename": "designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.5-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0004987__PROJECT15-19_C2.pdf-Figure5.5-1.png", + "caption": "Fig 5.5 Push button operated directional valve", + "texts": [], + "surrounding_texts": [ + "The Flow Control Valve is designed to adjust the resistance to air flow in a pneumatic circuit. It has one Inlet Port, one Outlet Port and a Control Knob." + ] + }, + { + "image_filename": "designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-22-1.png", + "original_path": "designv7-3/openalex_figure/designv7_3_0001898_tr_pdf_AD0817023.pdf-Figure10-22-1.png", + "caption": "Figure 10-22 is a detailed view of a typical suspension arm and torsion bar end supports. Cast armor steel support housings, one for each road wheel, are bolted over openings in the hull bottom. Each support houses a bearing-mounted suspension arm spindle and includes a seat for the opposite torsion bar ping. The road wheel suspension arm is usually press-fitted on the hollow, externally serrated spindle. Forged one-piece arm and spindle units are also in production. The spindle is internally serrated to receive the torsion bar spring. One serration on the spindle and on the torsion bar is omitted to facilitate removal and installation.", + "texts": [], + "surrounding_texts": [ + "AMCP 706-356\nStresses in the torsion bar anchor member or hub will uot be as high as they are in the bar, although high local stresses exist. The female splines must also be designed with good fillets in order to avoid high stress concentrations, but shot peeniug is not necessary.\nThe high pressure angle required for durable spline design will produce large radial components of the spline pressures and, therefore, a tendency to burst the anchor as if it were loaded by internal hydraulic pressure.\nThe female splines should be longer than the male splines and so positioned that they will overlap the male splines at both ends, regardless of tolerances and assembly variations.\nThe hardness of the anchor can be considerably lower than that of the bar. In many installations it has been held below Rockwell C-30. In order to make broaching possible after heat treatment, the hardness .should not exceed Rockwell C-36.\n10-19.1.4 Materials and Processing of Steel Torsion Bars\nDetailed material and processing schedules for steel bars are given in Reference 32. In general, alloy steels such as SAE 9260, 9262, and 8660 and carbon steel SAE 1046 are used for torsion .bar springs. For satisfactory results, it is mandatory that the processing schedule developed for military torsion bar springs be followed. This schedule includes factors such as: (a) composition, (b) bar size, (c) quality requirements, (d) deep etch tests, (e) fracture tests, (f) Jominy hardenability tests, (g) end upsetting, (h) normalizing, (i) straightening, (j) rough turning, (k) finish grinding, (1) Magnafiux inspection, (m) spline cutting, (n) heat treatment, (o) quenching, (p) tempering, (q) final hardness testing, (r) final straightening, (s) shot peeniug, (t) presetting, and (u) protective coatings.\nThe presetting and shot peening processes are advisable for the severe, unidirectional loading experienced in military service. For torsion bars made of through-hardened steel treated to Rockwell C-50, Reference 32 recommends a maximum applied shear strain -f\u201e of 0.022 radian during the presetting operation. This will result in a permanent set\nof about 0.005 to 0.008 radian. The shear strain Y\u201e may be calculated from\n9ad Y\u00ab = 1 / far 57.3 V I 114.6 I , in./in.\n(10-60)\nwhere\n9a = maximum angle of twist (during presetting), deg\nI = active length of the bar, in. d,r = bar diameter and radius, respectively, in.\nThe constant 57.3 converts units of shear strain to in./in.\nFor maximum endurance under repeated loading, shot peening is also required. This should be done prior to the presetting process. Presetting is of no value when reversal of torque is present.\n10-19.1.5 Conventional Lateral Installations At the present time, laterally installed torsion bar suspension systems are used on all American production tanks. The basic arrangement of these systems is essentially the same for each type of tank, the major difference being the number and size of road wheels required. The interchangeability of many of the components, the simplicity of construction, the ease of maintenance, and the increased spring protection against ballistic attack are factors that have contributed to the standardization of this suspension system. A disadvantage is the increase in tank height caused by locating the torsion bars between the turret floor and the bottom of the hull.\nThe road wheels of the torsion bar suspension are fully independent, each mounted on a solid forged suspension arm (Figure 10-4). The arm is attached rigidly to a spindle carried in roller bearings in a cast support housing bolted to the bottom of the hull. Turning of the spindle in its bearings is spring-controlled by a torsion bar engaged internally by splines with the spindle. On some tanks a track-adjusting compensating wheel is attached to the front road wheel suspension arm through an adjustable link. On other tanks an individually sprung tensioning idler roller bears against the track behind the rear road wheel. Track supportrollers are used in most suspensions to support the returning tracks above the road wheels.\n10-25", + "Direct-acting shock absorbers are attached between the hull and the suspension arms of the extreme front and rear road wheels and a number of intermediate wheels, depending on the need for damping. Road wheels at or near the center of the tank are rarely equipped with shock absorbers because their location reduces the need for shock control. A volute bumper spring is attached to the hull over each suspension arm to limit and cushion extreme arm travel. In some suspension designs, solid bumper stops are used for suspension arms near the center of the vehicle.\nLongitudinal torsion bar springs have been developed for nonmilitary wheeled vehicles. These are used in conjunction with the link systems discussed in Chapter 9.\nInterconnected torsion bar systems have been developed for several nonmilitary wheeled vehicles in order to have equal pitch and bounce frequencies of the sprung mass.\n10-19.1.7 Torsion Bar With Tube Combination torsion bar springs consisting of a solid member and a tubular member, with the former positioned within the latter, permit the use of relatively short bars. The combination also permits either series or parallel arrangements of the individual springs.\n10-19.1.7.1 Series Arrangement\nFigure 10-23 (A) shows the schematic of a series\ncombination of torsion bar springs. In a series arrangement, the total angular deflection for a given force or torque equals the sum of the angular deflections of each spring as if each carried the entire load. If a torque T is applied to the disk J of the system in Figure 10-23(A), the total deflection of the disk is %T = \u00a9j + \u00a92 = T/kn + T/ktssince 0r =: T/kie, the equivalent torsional spring rate of the bar kte can be expressed as\nkte = Jcti kt2 in.-lb/rad (10-61)\n10-19.1.7.2 Parallel Arrangement\n10-26", + "AMCP 706-356\nk|.