New design methods of actuator saturation compensators for proportional, integral and derivative controllers

Abstract

This paper proposes five new schemes of saturation compensator designs for PID (proportional, integral and derivative) controllers. Unlike previous works, these are derived using frequency domain techniques. Based on stability analysis of the compensated systems, comparisons of stabilities of the compensation schemes relative to each other are established, with the result that their relative orders depend only on the PI/PID parameters. A new class of variable-structure compensators is also proposed. These variable-structure compensators combine the advantages of their individual constituents to achieve better results. Design procedures, for both fixed- and variable-structure compensators, are then presented as the main theme of this paper. Results for the relative stabilities and design procedures are illustrated with examples, showing the validity and superiority of the proposed methods.