3.1.  INTRODUCTION

The purpose of this chapter is to illustrate the procedures used for deriving the state equations and transfer-function representation for several common linear control-system elements. This is a very important step that must be mastered before considering the determination of performance and stability of various kinds of control systems.

In general, the devices that are encountered can be classified as being electrical, mechanical, electromechanical, hydraulic, thermal, etc. The emphasis here will be to describe the state equations and transfer functions for linear control-system elements that are representative of these classes. Nonlinear devices are discussed in Chapter 5 on Nonlinear Control-System Design in the accompanying volume.