ABSTRACT
Chapters 13 through 15 deal with the improvement of system performance in the time and frequency domains, respectively, by conventional design procedures. Such procedures are based on an analysis of the open-loop transfer function and yield an improved closed-loop response as a consequence of properly designed cascade and/or feedback compensators. The design method presented in this chapter is based upon achieving a desired or model control ratio MT(s), that is, this is a pole-zero placement method. Section 15.2 describes the modeling of a desired closedloop transfer function. This chapter introduces the concept of feeding back all the system states to achieve the desired improvement in system performance. The design concepts developed with conventional control theory are also used to design state-variable feedback. The state-variablefeedback concept requires that all states be accessible in a physical system, but for most systems, this requirement is not met; that is, some of the states are inaccessible. Techniques for handling systems with inaccessible states are presented in Chapter 17. The state-variable-feedback design method presented in this chapter is based upon achieving a desired closed-loop state equation or a desired control ratio for a single-input single-output (SISO) system. Synthesis methods using matrix methods for multiple-input multiple-output (MIMO) systems are available in the literature [1-14]. Following the convention often used with the state-variable representation of systems, the output and actuating signals are represented in this chapter and Chapter 17 by y(t) and u(t) instead of c(t) and e(t), respectively.
