Many embedded engineers and programmers who need to implement basic process or motion control as part of a product design do not have formal training or experience in control system theory. Although some projects require advanced and very sophisticated control systems expertise, the majority of embedded control problems can be solved without resorting to heavy math and complicated control theory. However, existing texts on the subject are highly mathematical and theoretical and do not offer practical examples for embedded designers. This book is different; it presents mathematical background with sufficient rigor for an engineering text, but it concentrates on providing practical application examples that can be used to design working systems, without needing to fully understand the math and high-level theory operating behind the scenes. The author, an engineer with many years of experience in the application of control system theory to embedded designs, offers a concise presentation of the basics of control theory as it pertains to an embedded environment.
- Paperback; 320 pages
- Author: Tim Wescott
- Publisher: Newnes; Pap/Cdr edition (April 3, 2006)
- Language: English
- Dimensions: 9.5 x 7.4 x 0.9 inches
- Weight: 1.5 pounds
Table of Contents
Applied Control Theory for Embedded Systems is written in eleven chapters. The basic organization of the book is to introduce the concept of control theory, present the theoretical underpinnings of dynamic system analysis using the z transform, then show how to use the theory to solve practical problems.
Chapter 1, The Basics, orients the reader to basic control system concepts. It covers what a control system is; it discusses the difference between open and closed loop control; it defines the kind of controller that will be assumed throughout the rest of the book; and it distinguishes executive, high-level control from the low-level control discussed in the rest of the book.
Chapter 2, Z Transforms, presents the mathematical theory that lies at the core of nearly all sampled-time control solutions. It defines terms 'signal' and 'system'; it gives a short review of difference equations and their solution; presents the z Transform, the inverse z transform and z transform properties; it introduces and defines the notion of a transfer function; it shows how to determine system stability using z domain analysis; and it shows how z domain analysis relates to frequency response and frequency response analysis.
Chapter 3, Performance, defines various performance terms that are useful and commonly used in industry. It defines performance terms for both the frequency domain and time domain, in ways that can be traced from an original system specification to the actual system behavior.
Chapter 4, Block Diagrams, presents the block diagramming language used by control systems engineers to describe dynamic systems. Several different commonly used block diagramming dialects are presented, and the chapter shows how block diagramming language is used to start with a complex block diagram that describes a system's structure to a simple one that describes its behavior.
Chapter 5, Analysis, shows how to go from a general description of a systems behavior to a general description of its performance and stability characteristics. This is the information that one uses in real applications to decide if a system will be reliable in the field, and if it will meet performance specifications. This chapter presents root locus, Bode plot, and Nyquist analysis, and shows how these methods tie in with one another and with real world problem solutions.
Chapter 6, Design, shows how to use all of the tools presented so far to go from a system description and a performance requirement to a controller topology with tuning numbers. This chapter presents the notion of a controller as a filter; it shows various compensation topologies; it shows different types of compensators; and it presents a design flow for control systems.
Chapter 7, Sampling Theory, shows how to relate sampled-time analysis and design information with the continuous-time world. It describes the sampling process, aliasing and reconstruction of signals. It shows how to analyze the behavior of collections of unrelated signals with power-level analysis; it describes noise analysis; it describes various sorts of ways that the sampling process in the real world isn't perfect and how to model these imperfections; it presents the Laplace transform for continuous time signals and systems; and it shows how to go from a continuous time system model to a sampled time model that can be used for design.
Chapter 8, Nonlinear Systems, gives a synopsis of nonlinear systems design. While a full treatment of nonlinear system design would require several books, this chapter presents the most commonly used methods to deal with nonlinearities in a straightforward, sensible manner. The chapter covers the charecteristics of nonlinear systems that make them difficult to deal with; it presents some common nonlinearities; and it shows how to deal with these nonlinearities either by pretending that they don't exist, by complementing them with nonlinearities in one's controller, or both.
Chapter 9, Measuring Frequency Response, presents one of the oldest, simplest, and most robust methods of system identification for controller design. It shows how to measure a plant's frequency response in isolation; how to measure a plant's frequency response when it is operating in closed loop; it discusses some real-world roadblocks and quirks involved in frequency response measurement; and it develops some software that one can use to perform frequency response measurements.
Chapter 10, Software Implications, presents the special issues that are raised when one uses a digital computer to implement controllers. It covers the various data types that can be used to represent signals; it covers the problems associated with quantization and overflow; it discusses resources issues such as memory usage and processor speed; and it gives a nice set of controller implementation examples in the three most popular data types.
Chapter 11, Afterword lists the software tools and gives an annotated bibliography for the book.