Web-guiding systems

Web-guiding systems are used in the converting industry to position flat materials, known as webs, before processing. They are typically positioned just before a critical stage on a converting machine. Each type of web guiding system uses a sensor to monitor the web position for lateral tracking, and each has an actuator to shift the running web mechanically back on course whenever the sensor detects movement away from the set path. Actuators may be pneumatic or hydraulic cylinders, or some kind of electromechanical device. Because the web may be fragile — particularly at its edge — non-contact sensors are used. These sensors may be pneumatic, photoelectric, ultrasonic, or infrared. The system’s controls must put the output signals from the sensors in to a form that can drive the actuator.
Web guiding systems work at high speed, constantly making small adjustments to maintain the position of the material. The latest systems use digital technology and touch screen operator interfaces to simplify set up. Web guiding systems are used on slitting machines, slitter rewinders, printing presses, coating and laminating machines.
History.
In 1939, Irwin Fife invented the first web guide in his Garage in Oklahoma City, Oklahoma, solving a newspaper owner’s challenge of keeping paper aligned in his high-speed newspaper press.
Active Guiding Systems.
Active guiding systems are composed of a sensor, an actuator connected to a guide mechanism, and a controller. The sensor can be any detector, which can reliably pick up the edges of a web. The most common types of sensors are pneumatic (only works with nonporous webs), optical (works well with opaque webs), ultrasonic (works with most material), or paddies (thick webs). Recent developments have introduced to the industry a new sensor technology based on light scattering and spatial filtering that allows the use of an optical sensor to detect the edge of any material. The web must be flat (free of curl) and stable (free of flutter) through the edge sensor. For this and other reasons, the sensor is often placed near a roller. If two sensors are used, the web could be guided to the front edge, back edge, or center. Common active guide systems include steering guide (remotely pivoted guide), displacement guide (offset-pivot guide), unwind guide, and rewind guide.
Tension Adjustment Challenge.
Tension adjustment is necessary due to several mechanical factors: oscillations caused by mechanical misalignments, differing inertial response (lag) of mechanical elements during web acceleration, out-of-round unwind and tension rolls, slipping through nip rolls, and over-aggressive web-guide correction. Several technical process and control issues also affect tension: tension setpoint changes, phase offset on driven rolls, tension bleed from one zone to another, and thermal effect (contraction/expansion) as the substrate passes through various processes. It is impossible to eliminate all factors requiring tension adjustment. Variance in any one factor in a zone necessitates changes in tension control and web speed. Consequently, with coupled tension zone control, jitter is inevitable in a continuous web where the controllers cause a feedback loop.
Precise control of the system is essential. If the line speed of web is reduced, the amount of lateral displacement error that can be controlled by the steering guide system also decreases. If the input error decreases, the lateral displacement error also becomes smaller. Lateral displacement occurs on the transport web by the air blow from the dryer and the increase of blowing frequency can reduce the lateral displacement.


Heidenhain

Dr. Johannes Heidenhain GmbH is a privately owned enterprise located in Traunreut, Germany. Heidenhain manufactures numerical controls for machine tools, as well as mechatronic measuring devices for length and angle.
Their linear and angle encoders are built for use in automated machines and systems, particularly in machine tools.
History.
The company began as a metal etching factory founded in Berlin by Wilhelm Heidenhain in 1889 that manufactured templates, company plaques, product labels, and scales.
In 1928 Heidenhain invented the Metallur process. This lead-sulfide copying process made it possible for the first time to make exact copies of an original grating on a metal surface for industrial use. By 1943, Heidenhain was producing linear scales with accuracy of ± 15 µm and circular scale disks with accuracy of ± 3 angular seconds.
After World War II, in 1948, Dr. Johannes Heidenhain, a pupil of Otto Hahn, founded the present company in Traunreut.
Its invention of the Diadur process enabled it to apply very fine structures of chromium on suitable substrates, such as glass.
The Diadur process was the basis in 1952 for adding optical position measuring devices for machine tools to the product program. These were followed in 1961 by photoelectrically scanned linear and angle encoders.
In 1968 Heidenhain manufactured its first digital readouts.
The first Heidenhain numerical control was launched in 1976.
In 1987, a linear encoder series operating on the principle of light interference was introduced. It permitted measuring steps as fine as one nanometer.
According to Heidenhain, in 2006 the company had regional sales locations in 43 countries and employed about 7,000 people, 2,600 of whom worked in the main facility in Traunreut, Germany.
By the end of 2006 the company had manufactured about 10.5 million linear or angle encoders, 420,000 position displays and nearly 200,000 CNC controls.
Critique of Activities in Russia.
After the 2022 Russian invasion of Ukraine, the Chief Executive Leadership Institute of the US Yale University criticized that Heidenhain was still operating in Russia through a third party, which was not disclosed publicly. Heidenhain products are used in the Russian arms industry.


John Doyle (engineer)

John Comstock Doyle is the John G Braun Professor of Control and Dynamical Systems, Electrical Engineering, and BioEngineering at the California Institute of Technology. He is known for his work in control theory and his current research interests are in theoretical foundations for complex networks in engineering, biology, and multiscale physics.
Education.
He earned a B.S. and an M.S. in electrical engineering from the Massachusetts Institute of Technology in 1977 and a Ph.D. in Mathematics from the University of California, Berkeley in 1984 with his thesis titled "Matrix interpolation theory and optimal control".
Work.
Doyle's early work was in the mathematics of robust control, linear-quadratic-Gaussian control robustness, (structured) singular value analysis, and H-infinity methods. He has co-authored books and software toolboxes, and a control analysis tool for high performance commercial and military aerospace systems, as well as other industrial systems.
Awards.
Doyle earned the IEEE W.R.G. Baker Prize Paper Award (1991), the IEEE Automatic Control Transactions Axelby Award twice, and the AACC Schuck award. He also has been awarded the AACC Donald P. Eckman Award, the 2004 IEEE Control Systems Award and the Centennial Outstanding Young Engineer Award.


Lightweight software test automation

Lightweight software test automation is the process of creating and using relatively short and simple computer programs, called lightweight test harnesses, designed to test a software system. Lightweight test automation harnesses are not tied to a particular programming language but are most often implemented with the Java, Perl, Visual Basic .NET, and C# programming languages. Lightweight test automation harnesses are generally four pages of source code or less, and are generally written in four hours or less. Lightweight test automation is often associated with Agile software development methodology.
The three major alternatives to the use of lightweight software test automation are commercial test automation frameworks, Open Source test automation frameworks, and heavyweight test automation. The primary disadvantage of lightweight test automation is manageability. Because lightweight automation is relatively quick and easy to implement, a test effort can be overwhelmed with harness programs, test case data files, test result files, and so on. However, lightweight test automation has significant advantages. Compared with commercial frameworks, lightweight automation is less expensive in initial cost and is more flexible. Compared with Open Source frameworks, lightweight automation is more stable because there are fewer updates and external dependencies. Compared with heavyweight test automation, lightweight automation is quicker to implement and modify. Lightweight test automation is generally used to complement, not replace these alternative approaches.
Lightweight test automation is most useful for regression testing, where the intention is to verify that new source code added to the system under test has not created any new software failures. Lightweight test automation may be used for other areas of software testing such as performance testing, stress testing, load testing, security testing, code coverage analysis, mutation testing, and so on. The most widely published proponent of the use of lightweight software test automation is Dr. James D. McCaffrey.


Flexible manufacturing system

A flexible manufacturing system (FMS) is a manufacturing system in which there is some amount of flexibility that allows the system to react in case of changes, whether predicted or unpredicted.
This flexibility is generally considered to fall into two categories, which both contain numerous subcategories.
Most flexible manufacturing systems consist of three main systems:
The main advantages of a flexible manufacturing system is its high flexibility in managing manufacturing resources like time and effort in order to manufacture a new product.
The best application of a flexible manufacturing system is found in the 'production of small sets of products like those from a mass production.
Flexibility.
Flexibility in manufacturing means the ability to deal with slightly or greatly mixed parts, to allow variation in parts assembly and variations in process sequence, change the production volume and change the design of certain product being manufactured.
Industrial FMS communication.
An industrial flexible manufacturing system consists of robots, computer-controlled Machines, computer numerical controlled machines (CNC), instrumentation devices, computers, sensors, and other stand alone systems such as inspection machines. The use of robots in the production segment of manufacturing industries promises a variety of benefits ranging from high utilization to high volume of productivity. Each Robotic cell or node will be located along a material handling system such as a conveyor or automatic guided vehicle. The production of each part or work-piece will require a different combination of manufacturing nodes. The movement of parts from one node to another is done through the material handling system. At the end of part processing, the finished parts will be routed to an automatic inspection node, and subsequently unloaded from the Flexible Manufacturing System.
The FMS data traffic consists of large files and short messages, and mostly come from nodes, devices and instruments. The message size ranges between a few bytes to several hundreds of bytes. Executive software and other data, for example, are files with a large size, while messages for machining data, instrument to instrument communications, status monitoring, and data reporting are transmitted in small size.
There is also some variation on response time. Large program files from a main computer usually take about 60 seconds to be down loaded into each instrument or node at the beginning of FMS operation. Messages for instrument data need to be sent in a periodic time with deterministic time delay. Other types of messages used for emergency reporting are quite short in size and must be transmitted and received with an almost instantaneous response.
The demands for reliable FMS protocol that support all the FMS data characteristics are now urgent. The existing IEEE standard protocols do not fully satisfy the real time communication requirements in this environment. The delay of CSMA/CD is unbounded as the number of nodes increases due to the message collisions. Token bus has a deterministic message delay, but it does not support prioritized access scheme which is needed in FMS communications. Token Ring provides prioritized access and has a low message delay, however, its data transmission is unreliable. A single node failure which may occur quite often in FMS causes transmission errors of passing message in that node. In addition, the topology of Token Ring results in high wiring installation and cost.
A design of FMS communication that supports a real time communication with bounded message delay and reacts promptly to any emergency signal is needed. Because of machine failure and malfunction due to heat, dust, and electromagnetic interference is common, a prioritized mechanism and immediate transmission of emergency messages are needed so that a suitable recovery procedure can be applied. A modification of standard Token Bus to implement a prioritized access scheme was proposed to allow transmission of short and periodic messages with a low delay compared to the one for long messages.