PREFACE
The goal of the Second Edition of Modern Control System Theory and Design is to present a unified treatment of conventional and modern continuous control systems, and to show how to apply the theory presented to realistic design problems. My main objective has been to produce an easily understandable book from the reader’s viewpoint. It is written in an integrated manner so one can clearly proceed from the first to the last chapter. Having been a visitor for many years for the Accrediting Board for Engineering and Technology (ABET), I can appreciate the problems faced by professors who are trying to meet the design requirements of control-system courses. This book addresses this problem by including many realistic design examples.
This book is intended for an introductory course in control systems and for the practicing control-system engineer who wishes to master control systems through self-study. Its contents correspond to courses that I have taught at universities and in industry. It reflects my industrial experience with these corporations, which is coupled with extensive teaching experience in both university and industrial programs.
New Enhancements to the Second Edition
This Second Edition contains many of the new developments and applications in the control-system field that have occurred since the 1992 publication date of the first edition. The following are the enhancements and new features which have been incorporated into the Second Edition of Modern Control System Theory and Design:
1. Addition of a new chapter (Chapter 8) entitled “Modern Control-System Design Using State-Space, Pole Placement, Ackermann’s Formula, Estimation, Robust Control, and H∞ Techniques”.
No other control-system textbook contains all of this recent material presented in a cohesive, easy to understand, manner for undergraduate students and practicing engineers.
2. Addition of new sections at the end of each chapter containing illustrative problems and their solutions which cover the material in each chapter.
These sections include completely worked out illustrative problems which, as well as covering the salient features of the material presented in the individual chapters, emphasize recent applications. These problems constitute an integral part of the text.
3. MATLAB™ (MATLAB is a trademark of The MathWorks, Inc.) is integrated into the text in the Second Edition, in addition to the free software contained in the Modern Control System Theory and Design Toolbox which complements the book and contains MATLAB solutions to computational problems, and can be retrieved free from The Math Works anonymous File Transfer Protocol (FTP) server at ftp://ftp.mathworks.com/pub/books/shinners. The Modern Control System Theory and Design Toolbox available with the Second Edition of this book is designed to run with MATLAB for Windows (and predecessor versions), and the Student Edition of MATLAB for Windows (and predecessor versions).
No prior knowledge of MATLAB™ is assumed in this book. MATLAB is now considered a control-system industry standard. All computational problems are solved with MATLAB.
In addition to the solutions to computational problems, the Modern Control System Theory and Design Toolbox software contains the following: (a) a Tutorial File explaining the MATLAB fundamentals, notations, and the use of the software; (b) a Demonstration M-file which gives an overview of the various utilities; (c) a synopsis file that reviews and highlights features of each chapter. Together, the integrated learning package and the MATLAB software are self-contained, so it is not necessary to purchase additional books/materials to learn how to use MATLAB, the Modern Control System Theory and Design Toolbox, or the various applications within this book. In this manner, the user of this book has available a toolbox of features/utilites created to enhance The MathWorks’ Control System Toolbox, optionally utilize The MathWorks’ Simulink, Nonlinear and Symbolic Toolboxes, as well as supply the computer-generated solutions of the problems in the book. The Modern Control System Theory and Design Toolbox runs equally well with The Student Edition of MATLAB as it does with the professional version of MATLAB (with or without The MathWorks’ Control System Toolbox, Simulink, the Nonlinear Toolbox, or the Symbolic Toolbox). Accordingly, the resultant presentation of this book is an integration of computer-aided software engineering (CASE) and computer-aided design (CAD) techniques with the control-system analysis and design methods illustrated.
For those who do not have MATLAB, a feature of this book is a complete set of working digital-computer programs containing their logic flow diagrams, listings, and representative output based on the programs’ application to practical design problems.
4. Many new problems have been added at the ends of the chapters. Coupled with the additional worked out illustrative problems added to the new sections in each chapter, this greatly increases the total number of problems in the Second Edition.
5. The Solutions Manual has been updated to contain solutions to new problems at the ends of the chapters. Answers contained in the Answers to Selected Problems in the back of the book have been increased to contain answers to the remaining problems at ends of chapters.
Primary Features of Modern Control System Theory and Design
1. Unifies and blends the conventional and modern approaches. It uses the conventional block-diagram-transfer function and state-variable methods in parallel throughout the book. Modern control-system design techniques using the statespace approach, pole placement, estimation, robust control, and H∞ are presented in addition to the classical Nyquist, Bode, Nichols, and root-locus methods. In addition, the modern state-space, pole placement, Ackermann’s formula for pole placement, estimation, robust control, and the H∞ method present ideas for design projects at the undergraduate level and ideas for specialization and future research at the graduate level.
2. Emphasizes design. The development of theoretical topics is coupled with clear applications of the theory in engineering design. Recognizing that control theory is interdisciplinary and cuts across all specialized engineering fields, I have presented modern illustrations and practical problems from the fields of robotics, space-vehicle systems, aircraft, submarines, hydrofoils, servomechanisms, economics, management, biomedical engineering, and nuclear reactor systems. This should prove to be of interest to electrical, mechanical, aerospace, system, chemical, nuclear, biochemical, and industrial engineers.
3. Presents a complete set of working digital computer programs and summarizes commercially available software packages available for control system analysis in addition to the many solutions presented in the text using MATLAB. Although computer techniques are extremely valuable to the student and the practicing engineer, I believe one must first understand the details of the techniques being applied so that computer results can be properly interpreted and judged for their analytical reasonableness. Therefore, I present basic theory while applying it to design problems with and without computer solutions.
4. Covers a variety of topics of recent importance. In addition to covering modern state-space design techniques including pole placement, Ackermann’s formula for pole placement, estimation, robust control, and the H∞ method for design, the presentation also includes controllability, observability, and linear-state-variable feedback (including the design of controllers, estimators, and compensators).
5. Adapts to the student’s training, ability, and to various curricula.
6. Contains problems (with answers to approximately one-third). This is helpful to the student and also to the practicing control-system engineer using the book for self-study. The available MATLAB computer-generated solutions will guide the reader in understanding the approach used for solving the problems.
7. Offers an accompanying Solutions Manual (available to professors) containing detailed solutions to the remaining problems whose answers are not found in this book. As an aide to the professors using this book, methods for enchancing the students’ learning environment, a listing of control system journals, and design chart/graphical templets are also contained in the Solutions Manual.
By means of these features, Modern Control Systems Theory and Design is a computer-oriented, state-of-the-art book that is comprehensive and unique and fills a rather large gap in the existing literature on feedback control-system design.
Chapter Organization
Chapter 1 introduces the concept of open-loop and closed-loop control systems, and presents the state of the developments of the control-system field today, with a preview of the future. Chapter 2 reviews Fourier methods, the Laplace transform, and the transfer-function method. In addition, it introduces the signal-flow graph, state-variable concepts, and the state transition matrix. A tutorial on MATLAB is introduced into the text in Chapter 2 for the reader who has had no prior knowledge of MATLAB. MATLAB programs for obtaining partial-fraction expansion and transforming between the state-space form and the transfer function are developed. The transfer-function and state-variable representation of several common devices found in control systems are derived in Chapter 3. The concepts of conservation and analogy are also introduced in this chapter. Chapter 4 focuses attention on second-order systems because they occur so frequently, most basic transient response definitions are based on second-order systems, and many higher-order systems can be approximated as second-order systems. It also provides guidelines for selecting the optimum damping ratio of a specific system. A method for modelling the transfer functions of control systems from available data is presented.
Chapter 5 addresses control-system sensitivity and accuracy, and presents various performance criteria such as the ITAE criterion. A comprehensive treatment of techniques for determining stability, together with several useful and practical examples, is given in Chapter 6. The viewpoints presented include the state-variable, the Routh-Hurwitz, Nyquist and Bode-diagrams, Nichols-chart, and root-locus methods. MATLAB programs for obtaining the Nyquist and Bode diagrams, Nichols chart, and root locus are developed and applied. In addition, non-MATLAB working digital-computer programs are also developed and applied. A review of commercially available software packages is also presented. A comparison is presented of the Nyquist-diagram, Bode-diagram, Nichols-chart, and root-locus methods for 12 commonly used transfer functions; guidelines are presented for using these stability methods. The concepts of stability, presented in Chapter 6, are applied in great detail to the design of linear control systems in Chapter 7. Single-degree and two-degrees of-freedom compensation techniques using cascade-compensation and minor-loop feedback compensation techniques are developed and applied. Phase-lag, phase-lead, and phase-lag-lead networks are illustrated, in addition to proportional-plus-integral-plus-derivative (PID) compensators.
This volume concludes with Chapter 8, a new chapter for the Second Edition, which is dedicated to presenting modern control-system design using state-space methods, including pole-placement design using linear-state-variable-feedback, Ackermann’s formula for design using pole placement, and estimator design in conjunction with the pole placement approach using linear-state-variable feedback. The concepts of controllability and observability are introduced. Robust control is developed and applied to a variety of problems. The modern H∞ control concepts are introduced, developed, and applied. The chapter concludes with a presentation of linear algebraic aspects of control-system design computations, and several illustrative problems and solutions.
The flexibility of Modern Control System Theory and Design in adapting to the course level, the various curricula, and the student’s training and ability is quite evident from this content summary. Its design orientation will also make it an excellent choice for the practicing engineer.
The Learning Package
The following educational materials comprise the learning package for the Second Edition of Modern Control System Theory and Design, and supplement and enhance this textbook:
- Modern Control System Theory and Design Toolbox, available free from The MathWorks Inc. anonymous FTP server at ftp://ftp.mathworks.com/pub/books/shinners. This software contains MATLAB solutions to the computational problems in this book. In addition, the Modern Control System Theory and Design Toolbox software contains the following features:
- Tutorial File explaining the MATLAB fundamentals, notations, and the use of the software.
- Demonstration M-File which gives an overview of the various utilities.
- Synopsis file that reviews and highlights features of each chapter.
The Modern Control System Theory and Design Toolbox runs equally well with the professional and Student Edition of MATLAB. By virtue of the Modern Control System Theory and Design Toolbox. and the fact that MATLAB is also integrated into this textbook throughout, it is not necessary for the reader to buy a supplementary book to learn how to use MATLAB.
- Solutions Manual for Modern Control System Theory and Design, second edition, by Stanley M. Shinners contains the detailed solutions to approximately 66% of the problems at the ends of each chapter. The Solutions Manual is available only to qualifying faculty members.
ACCOMPANYING COMPANION VOLUME
An accompanying companion volume has been written to Modern Control System Theory and Design, titled Advanced Modern Control System Theory and Design. It serves as an excellent book for a follow-up advanced college course to the introductory course which this book serves. In addition, it can serve as an excellent text for practicing control system engineers who need to learn more advanced control system subjects which are required to perform their tasks. Advanced Modern Control System Theory and Design begins with a review of introductory control system analysis concepts and is then followed by Chapters 7 and 8 of the first volume and includes the following chapters:
- Digital Control-System Analysis and Design which extends the continuous concepts presented to discrete systems.
- Nonlinear Control-System Design which extends the linear concepts presented in this volume to nonlinear systems.
- Introduction to Optimal Control Theory and its Applications presents such important topics as dynamic programming and the maximum principle, and applies it to the space attitude control problem and the lunar soft-landing problem.
- Control-System Design Examples: Complete Case Studies presents the complete case studies of five control system design examples which illustrate practical design projects.
Advanced Modern Control System Theory and Design contains the important subjects that a professor requires in a follow-up course. It is also very important and useful to the practicing control system engineer who had only an introductory control system course as an undergraduate, and now must be concerned with digital control systems, nonlinearities and the other advanced techniques for a design project. This volume also contains these same features as Modern Control System Theory and Design:
- Sections at the end of each chapter containing illustrative problems and their solutions, separate from a problems section at ends of each chapter.
- MATLAB is also integrated into this textbook. In addition, free software which complements the book and contains MATLAB solutions to computational problems can be retrieved from The MathWorks anonymous FTP server.
- A Solutions Manual is available to professors and contains solutions to more than one-half of the problems at the end of each chapter. Answers to the remaining problems are contained at the end of the book.
ACKNOWLEDGMENTS
I am most grateful to my wife Doris for her encouragement, understanding, patience, and word-processing assistance throughout this project. In addition, I express thanks and appreciation to my parents for their efforts, encouragement, and inspiration. I thank the editor of my book at John Wiley & Sons, Mr. George Telecki, who managed the smooth production of the book, and to Lisa Van Horn of John Wiley & Sons for her professional production of this book.
STANLEY M. SHINNERS
Jericho, New York
March 1998