Control of high precision roll-to-roll manufacturing systems

The flexible electronic industry has been growing rapidly over the past decade. One of the barriers to commercialization is the high cost of manufacturing micro- and nano-scale printed electronics using traditional methods. Roll-to-roll manufacturing has been identified as a method of achieving low cost and high throughput. A dynamic model of a roll-to-roll system is presented. In all roll-to-roll applications, tension and velocity must be accurately controlled to desired reference trajectories to ensure a quality finished product. Additionally, a registration error model is presented for the control design. Minimization of the registration is the primary objective for flexible electronics, but web tension and velocity cannot be neglected. The model is needed in order to formulate a methodology that can simultaneously control tension, velocity, and registration error in the presence of disturbances. Micro and nano-scale features are susceptible to damage from friction between the web and the roller. Therefore, tension estimation techniques is highly desired to eliminate load cells from the system. The reduced order observer, extended Kalman filter, and an unknown input observer is presented. Development of tension and velocity control strategies have historically revolved around decentralized SISO control schemes. In order to achieve higher precision, a centralized MIMO strategy is proposed and compared to decentralized SISO. The advantage of the MIMO controller improved handling of the tension velocity coupling in roll-to-roll systems. The tension observer is introduced to the control design and evaluated for overall effectiveness. In simulation, the centralized MIMO control with the unknown input observer demonstrated superior tension and velocity tracking as well as minimal registration error. Development of the proposed MIMO control strategy can enable flexible electronic fabrication using roll-to-roll manufacturing.Mechanical Engineerin

Control Theory in Engineering

The subject matter of this book ranges from new control design methods to control theory applications in electrical and mechanical engineering and computers. The book covers certain aspects of control theory, including new methodologies, techniques, and applications. It promotes control theory in practical applications of these engineering domains and shows the way to disseminate researchers’ contributions in the field. This project presents applications that improve the properties and performance of control systems in analysis and design using a higher technical level of scientific attainment. The authors have included worked examples and case studies resulting from their research in the field. Readers will benefit from new solutions and answers to questions related to the emerging realm of control theory in engineering applications and its implementation

Recent advances in web longitudinal control

Stable web transport through processing machinery is critical in the web processing industry. Demands for improved performance under a wide variety of dynamic conditions and web materials are placing additional emphasis on developing new advanced control techniques. Further, technological advances in areas such as drive hardware, microprocessors, and sensors, are opening up new possibilities for implementing advanced control methods that are robust to a number of process and material variations and result in superior performance over existing industrial control methods.Mathematical models of fundamentals elements in a web process line are presented. A systematic procedure for computing the equilibrium inputs as well as reference velocities of all rollers based on the master speed reference is given. Recently developed robust control methods for web longitudinal control are described. Implementation of the controllers on two experimental platforms is given, and a sample of the experimental results is presented. Finally, some potential new directions and future research topics are discussed.Mechanical and Aerospace Engineerin

Síntesis de interpolación de los controladores para un sistema de accionamiento eléctrico multimotor que contiene un elemento enlazado elásticamente

Partial differential equations, integral, differential, or other equations describe multi-motor automatic electric drive systems containing elastic conveyor belts. Because of the elastic and distributive nature of the system parameters, the transfer function describing them is often a complex expression, containing not only the arguments as a linear system but also the inertial and transcendental components. This makes the precise control of tension and speed synchronously much more complicated than the centralized parameter system. A promising numerical solution based on the real interpolation method will simplify the procedure for synthesizing control loops while preserving the characteristic properties of objects with distributed parameters. The objective of the study is to propose a feasible solution for synthesizing the regulators based on the real interpolation method; it allows direct operation with the original transfer function containing the inertial and transcendental components. In this paper, we proposed an approach to synthesize the control system for objects with distributed parameters using the real interpolation method to reduce computational capacity and synthesis error while preserving the properties of this object class. Building an experimental model of the two-motor electric drive system containing an elastic conveyor to verify the effectiveness of the proposed algorithm. The simulation and experimental results indicate that the control system with the received regulators operating stably and meets the required quality criteria. It proves the efficiency of the synthesis algorithm based on the real interpolation method.Introducción: los sistemas de accionamiento eléctrico multimotor que incluyen transportadores elásticos son un ejemplo de sistemas típicos con parámetros distribuidos descritos por ecuaciones complejas. Debido a la naturaleza elástica y distributiva de los parámetros del sistema, la función de transferencia que los describe suele ser una expresión compleja que contiene los componentes inercial y trascendental. Problema: la naturaleza elástica y distributiva de los parámetros del sistema hace que el control preciso de la tensión y la velocidad sincrónicamente sea mucho más complicado que el sistema de parámetros centralizados. Metodología: se propone una solución numérica para sintetizar los reguladores basada en el método de interpolación real para reducir la capacidad computacional y el error de síntesis preservando las propiedades características de los objetos con parámetros distribuidos. Conclusión: la eficacia del algoritmo propuesto se verifica mediante un modelo experimental del sistema de accionamiento eléctrico de dos motores que contiene un transportador elástico. Los resultados de simulación y experimentales indican que el sistema de control con los reguladores recibidos opera de manera estable y cumple con los criterios de calidad requeridos. Originalidad: los resultados de la investigación se pueden aplicar en el desarrollo de sistemas centrales de control y monitoreo para líneas de producción automáticas con sistemas de accionamiento multimotor que incluyen transportadores

Mechatronics of systems with undetermined configurations

This work is submitted for the award of a PhD by published works. It deals with some of the efforts of the author over the last ten years in the field of Mechatronics. Mechatronics is a new area invented by the Japanese in the late 1970's, it consists of a synthesis of computers and electronics to improve mechanical systems. To control any mechanical event three fundamental features must be brought together: the sensors used to observe the process, the control software, including the control algorithm used and thirdly the actuator that provides the stimulus to achieve the end result. Simulation, which plays such an important part in the Mechatronics process, is used in both in continuous and discrete forms. The author has spent some considerable time developing skills in all these areas. The author was certainly the first at Middlesex to appreciate the new developments in Mechatronics and their significance for manufacturing. The author was one of the first mechanical engineers to recognise the significance of the new transputer chip. This was applied to the LQG optimal control of a cinefilm copying process. A 300% improvement in operating speed was achieved, together with tension control. To make more efficient use of robots they have to be made both faster and cheaper. The author found extremely low natural frequencies of vibration, ranging from 3 to 25 Hz. This limits the speed of response of existing robots. The vibration data was some of the earliest available in this field, certainly in the UK. Several schemes have been devised to control the flexible robot and maintain the required precision. Actuator technology is one area where mechatronic systems have been the subject of intense development. At Middlesex we have improved on the Aexator pneumatic muscle actuator, enabling it to be used with a precision of about 2 mm. New control challenges have been undertaken now in the field of machine tool chatter and the prevention of slip. A variety of novel and traditional control algorithms have been investigated in order to find out the best approach to solve this problem

Advanced controls for web handling: Ready for production?

The science of web handling has numerous control challenges. Longitudinal control is especially challenging because the machine is a distributed, high order, tightly coupled flexible system. Advanced controls were developed in the last few decades, and have been widely applied in several fields, most notably aeronautics, robotics, navigation, and extremely large-scale high-value industrial processes, such as petroleum refining. There have been numerous advanced web handling control strategies papers previously presented at this conference. However, there are few implementations of advanced controls in commercially available web handling equipment.The Proportional-Integral-Derivative (PID) controller was originally developed in the 1920's. The PID controller dominates web handling controls to this day; virtually all web handling is controlled by variations of the PID algorithm. While an optimized PID controller can perform well, there are superior control algorithms that have higher performance and more flexibility, but they have yet to displace even a small number of PID systems.While this paper is fundamentally on control topics, this presentation is targeted towards a general web handling audience; a general broad overview will be presented. This paper will provide a brief history of control, emphasizing the role of PID in industry. It will illustrate some of the circumstances that have limited the adoption of advanced web handling control strategies, and propose potential solutions to increase the rate of adoption of advanced web handling controls. In addition, several high value web handling problems that may greatly benefit from these strategies will be discussed

Advanced Fault Diagnosis and Health Monitoring Techniques for Complex Engineering Systems

Over the last few decades, the field of fault diagnostics and structural health management has been experiencing rapid developments. The reliability, availability, and safety of engineering systems can be significantly improved by implementing multifaceted strategies of in situ diagnostics and prognostics. With the development of intelligence algorithms, smart sensors, and advanced data collection and modeling techniques, this challenging research area has been receiving ever-increasing attention in both fundamental research and engineering applications. This has been strongly supported by the extensive applications ranging from aerospace, automotive, transport, manufacturing, and processing industries to defense and infrastructure industries

Modeling and control of web velocity and tension: An industry/university perspective on issues of importance

The goal of this paper is to provide an overview of current industrial practice in control of web velocity and tension and discuss some critical issues that require future research from the community which is pertinent to problems faced in the industry. It is well known that there is a considerable gap (and time lag) between what is currently practiced in various industries and what is being researched in academia and research laboratories. This gap appears to be much more significant in the web handling industry when compared to some other established industries such as aerospace, automobile, semiconductor manufacturing, and robotics, to name a few. There are a few plausible reasons for this. First, the number of products made from materials manufactured in rolled form is very large. Second, since a wide spectrum of materials is manufactured and processed in rolled form, machines that handle different materials are diverse and so is their operation. Yet, there is a substantial amount of commonality between various web process lines that handle different materials. Two key process variables that need to be monitored and controlled in almost all web process lines are web tension and velocity. The discussions in the paper will highlight and focus on issues related to modeling and control of these two key process variables.The paper will first give discussions on the "typical" webline, potential performance enhancements and commissioning improvements that modern control methods can provide, and advances in drive and microprocessor technology that allow implementation of modern controllers. A brief description of the models for web tension and velocity is given. Many modern control algorithms have been suggested for controlling tension and velocity in the recent years. But very few, if any, have been transferred to current industrial practice. One of the reasons is that the development and presentation of these new control strategies is often too abstract for controls engineers who are trained in implementing and tuning PID-type algorithms. The paper will examine some of these new control strategies whose implementation is relatively simple and present a reasonable level of complexity while providing superior performance to currently used PID techniques.Mechanical and Aerospace Engineerin

Nylon Tension PID Control During Raw Tire Assembly

The purpose of this study is to evaluate several control methods to see which one has the best control of nylon tension during raw tire assembly. After nylon application step of the tire building process, the shape of the tire will undergo inflation that causes the nylon layers to expand and produces tension gradient. To overcome such a problem, the process needs to preapply a nylon trip with a gradient of tension so the tension can be balanced after the inflation step. The study evaluated several PID controllers and gathered data to see which controller results in the best nylon tension gradient. The study also discusses the cost and simplicity of implementation as well as its overall performance