Introduction to Control Theory

Control theory may or may not be part of the electrical measurement curriculum, but it is such a common instrument in a physics laboratory that a fundamental understanding of its operation is necessary. This chapter focuses on the PID controller, feedback models and stability criteria, the need for integration and differentiation of the error signal and how to identify an unknown system. It is explained how control parameters are derived using rules of thumb (Ziegler–Nichol’s) or phase/gain margins. Finally, this chapter illustrates how a control algorithm can be implemented in a computer system using either Euler transformation or bilinear transformation.