PREFACE
The goal of Advanced Modern Control System Theory and Design is to present a unified treatment of advanced control system design techniques, and to illustrate how to apply the theory presented to realistic design problems. It assumes that the reader (student or practicing control system engineer) has completed an introductory control system course which has used any of the control system books which cover the subject at an introductory level. It can serve as an excellent book at universities for a follow-up advanced course (in the senior-year or at the graduate level) to an introductory course. It alleviates the need for a professor to request that their students purchase several control system books to cover various advanced subjects. This book contains a unified presentation of the advanced subjects that are of current interest for a follow-up course to an introductory course. In addition, it can serve as an excellent book for practicing control system engineers who need to learn more advanced control system subjects which are required to perform their tasks.
The book stands alone and does not assume that the reader has studied previously from my companion book Modern Control System Theory and Design, Second Edition. The book was written assuming that the reader has studied previously from any introductory control system book.
Throughout this book reference is made to various items in the companion volume, Modern Control System Theory and Design, Second Edition, to assist the reader in referencing introductory control system concepts. These references are indicated by a double dagger (‡) after the relevant item number.
The contents of this book correspond to advanced control system courses that I have taught at universities and in industry and reflects my industrial experience coupled with extensive teaching experience in both university and industrial programs.
The book has been written assuming that the reader will learn the subject in conjunction with a PC. Several very good control system software packages are available. MATLAB™ (MATLAB is a trademark of The MathWorks, Inc.) was selected for this book, and it is integrated into the text. MATLAB is now considered a control-system industry standard. All computational problems are solved with MATLAB.
In addition to the MATLAB programs integrated in the text, free MATLAB software and solutions to the computational problems in the book are available from The MathWorks. These can be downloaded from The MathWorks anonymous File Transfer Protocol (FTP) server at ftp://ftp.mathworks.com/pub/books/advshinners. The Advanced Modern Control System Theory and Design Toolbox software additionally 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 Advanced Modern Control System Theory and Design Toolbox, or the various applications with in 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 Advanced 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). The Advanced Modern Control System Theory and Design Toolbox is designed to run with MATLAB for Windows (and all predecessor versions), and the Student Edition of MATLAB for Windows (and all predecessor versions). 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 set of working digital-computer programs containing their logic flow diagrams, listings, and representative output based on the programs' application to practical design problems is also contained.
Advanced Modern Control System Theory and Design contains the important advanced control system subjects that a professor requires in a follow-up course to an introductory control system course in one book. It is also an important and useful reference for the practicing control system engineer who only had an introductory control system course as an undergraduate, and who now has to be concerned with advanced modern control design methods (such as robust control) to achieve challenging modern design goals incorporating digital control, nonlinearities, and the other advanced techniques for a design project.
Advanced Modern Control System Theory and Design contains the following important subjects presented in dedicated chapters:
- Linear-Control System Compensation and Design presents linear control systems design methods using the Bode-diagram method, Nichols Chart, and the root-locus method.
- Modern Control-System Design Using State-Space, Pole Placement, Ackermann's Formula, Estimation, Robust Control, and H∞ Techniques presents the modern approaches for designing linear control systems.
- Digital Control-System Analysis and Design extends the continuous concepts presented to discrete systems.
- Nonlinear Control-System Design 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 complete case studies of five control system designs which illustrate practical design projects.
Major Enhancement for Learning
Advanced Modern Control System Theory and Design provides dedicated sections at the end of each chapter (but before problems at ends of chapters) containing illustrative problems and their solutions which cover material in their respective chapter. This is a very important major enhancement for learning by students, and by practicing control system engineers using this book for self study.
Primary Features of Advanced Modem 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 state-space approach, pole placement, estimation, robust control, and H∞ are presented in addition to the classical Nyquist, Bode, Nichols, and root-locus methods. A chapter on digital controls extends the continuous concepts presented to discrete systems. Nonlinear control systems, and modern optimal control theory (including such important topics as dynamic programming and the maximum principle) are presented in this book. This interesting presentation also shows how we can extend our capabilities for analyzing and designing linear control systems to nonlinear control systems. It also introduces students to the optimal control concept (and its important applications) which adds another dimension to their capabilities. In addition, the modern state-space, pole placement, Ackermann's formula for pole placement, estimation, robust control, the H∞ method, nonlinear and optimal control chapters present ideas for design projects at the undergraduate level and ideas for specialization and future research at the graduate level. The concluding chapter presents the complete case studies of five design examples which illustrate the undergraduate type design projects.
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 they 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 dynamic programming and the maximum principle, Liapunov's stability criteria, Popov's method, the generalized circle criterion, 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.
By means of these features, Advanced 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 advanced control-system design.
Chapter Organization
After presenting an introduction to the subject in Chapter 1, the design of linear control systems is presented in Chapter 2. 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.
Chapter 3 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 in a dedicated section.
An extension of the continuous methods of analysis and design to digital control-system analysis and design is presented in Chapter 4. The characteristics of sampling, data extrapolators, z-transform theory, and stability analyses using mathematical tests, the Nyquist diagam, Bode diagram (in the w-plane), root locus, and Ragazzini's method are presented. MATLAB programs for obtaining the Bode and root-locus diagrams of discrete time systems are developed and applied. The digitization process and the design of digital filters are presented.
Chapter 5 discusses the theory of designing nonlinear systems along with practical examples. Included are linearizing approximations, the describing function, piecewise-linear approximations, the state-variable analysis technique (the phase plane), Liapunov's stability criteria, Popov's stability criterion, the generalized circle criterion, and the use of simulation. MATLAB programs for the analysis and design of nonlinear control systems using the describing function method are developed and applied. In addition, non-MATLAB working digital computer programs are also presented and used for applying the describing-function and state variable analyses using the phase-plane method. Guidelines for selecting the appropriate nonlinear control-system method(s) to use for a particular problem are presented. Chapter 6 introduces optimal control theory and presents its interesting applications. The following material is covered at an introductory level: calculus of variations, Bellman's dynamic programming, and Pontryagin's maximum principle. The maximum principle is applied to the space attitude-control and the lunar soft-landing problems.
The book concludes with Chapter 7 on complete case studies for designing five different control systems. These include the application of continuous linear control-system design, nonlinear control-system design, pole placement using linear-state-variable-feedback design, digital control-system design techniques, and the design of a robust control system are applied to practical problems. The book also contains Appendix A which is a tutorial for the effective use of MATLAB. This appendix is designed for self-study by the reader who is unfamiliar with MATLAB or needs a refresher, and is coordinated with this text. The book concludes with Appendix B on the characteristic response of second-order systems, and Appendix C on static accuracy.
The Learning Package
The following educational materials comprise the learning package for Advanced Modern Control System Theory and Design, and supplement and enhance this textbook:
- Advanced Modern Control System Theory and Design Toolbox, which is available free to the reader from The MathWorks Inc. anonymous FTP server at ftp://ftp.mathworks.com/pub/books/advshinners. This software contains MATLAB solutions to the computational problems in this book. In addition, the Advanced 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 Advanced Modern Control System Theory and Design Toolbox runs equally well with the professional and Student Edition of MATLAB. By virtue of the Advanced 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 Advanced Modern Control System Theory and Design 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 facuity members.
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
May 1998