Modeling and Control of Engineering Systems

Book Preface

This is an introductory book in the subject of modeling and control of engineering systems.It serves as both a textbook for undergraduate engineering students and entry-level graduate students, and a reference book for practicing professionals. As a textbook, it is suitable for courses in: modeling of dynamic systems, feedback control systems, control engineering, and design and instrumentation of control systems. There is adequate material in the book for two 14-week courses, one at the junior (third-year undergraduate) or senior (fourthyear undergraduate) level and the other at the first-year graduate level. In view of the analytical techniques, computer and software tools, instrumentation details, design methods, and practical considerations that are presented in the book, and in view of the simplified and snap-shot style presentation of more advanced theory and concepts, the book serves as a useful reference tool for engineers, technicians, project managers, and other practicing professionals in industry and in research laboratories, in the fields of control engineering, mechanical engineering, electrical and computer engineering, manufacturing and production engineering, aeronautical and aerospace engineering, and mechatronics. A control system is a dynamic system that contains a controller as an integral part. The purpose of the controller is to generate control signals, which will drive the process to be controlled (the plant) in the desired manner—to meet a set of performance specifications. Actuators are needed to perform control actions as well as to directly drive/operate the plant. Sensors and transducers are necessary to measure output signals (process responses) for feedback control; to measure input signals for feedforward control; to measure process variables for system monitoring, diagnosis and supervisory control; and for a variety of other purposes. Design is a necessary part as well, for it is design that enables us to build a control system that meets the performance requirements—starting, perhaps, with basic components such as sensors, actuators, controllers, compensators, and signal modification devices. The book addresses all these issues, starting from the basics and systematically leading to advanced concepts.

Control engineers should be able to model and analyze individual components or an integrated control system, design controllers, identify and select components for a control system, and choose parameter values so that the control system will perform the intended functions of the particular system while meeting a set of specifications. Proper control of an engineering system requires an understanding and a suitable “representation” of the system—a “model” of the system. Any model is an idealization of the actual system. Properties established and results derived are associated with the model rather than the actual system, whereas the excitations are applied to and the output responses are measured from the actual system. Modeling is often an essential task in control engineering. For instance, a good understanding of the system to be controlled may be gained through modeling and associated analysis and computer simulation. In fact a controller may be designed and its performance can be studied through modeling and computer simulation even before a physical controller is developed. Such an approach is often more economical and time effective. Furthermore there are control techniques called “model-based control” for which modeling is a requirement.

Important aspects of laboratory experimentation and instrumentation are included in the book. There are numerous worked examples, problems, and exercises, many of which are related to real-life situations and practical applications. Augmenting their traditional role, the problems at the end of each chapter serve as valuable sources of information not found in the main text. In fact, the student is strongly advised to carefully read all the problems in addition to the main text. Complete solutions to the end-of-chapter problems are provided in a Solutions Manual, which is available to instructors who adopt the book.

The manuscript for the original book evolved from the notes developed by the author for mandatory undergraduate courses in dynamic system modeling and feedback control, and entry-level graduate courses in control system instrumentation and modern control engineering for students in electrical and computer engineering, mechanical engineering, and chemical engineering at Carnegie Mellon University. During the development of the material for those courses, a deliberate attempt was made as well to cover a major part of the syllabuses for similar courses offered in the Department of Mechanical Engineering at the Massachusetts Institute of Technology. At the University of British Columbia, the original material was further developed, revised, and enhanced for teaching courses in dynamic system modeling, control systems, intelligent control, mechatronics, and control sensors and actuators. The material in the book has acquired an application orientation through the
author’s industrial experience at places such as IBM Corporation, Westinghouse Electric Corporation, Bruel and Kjaer, and NASA’s Lewis and Langley Research Centers.

The material presented in the book provides a firm foundation in modeling and control of engineering systems, for subsequent building up of expertise in the subjec —perhaps in an industrial setting or in an academic research laboratory—with further knowledge of control hardware and analytical skills (along with the essential hands-on experience) gained during the process.