Analysis of PID and PDF compensators for motion control systems

Traditionally, the PI(D) controller has been widely used in servo systems, while other types such as PDF (pseudo-derivative feedback) controller has been applied in some applications. In this article, characteristics of the above two types of compensator are analyzed by using a generalized controller structure in which the PID and the PDF controller are special cases. The classical frequency domain approach is used and the results are interpreted in terms of location of the system poles and zeros. Differences in reference tracking and disturbance regulation performance, steady-state error, and susceptibility to the noise and resonance are studied. The discussion starts with a velocity loop performance and is then extended to a position loop.<<ETX>>