PID CONTROL OF UNSTABLE TIME-DELAY SYSTEMS

A PID controller is designed by dominant poles placement method for an unstable first order plus time delay system. The robustness of the pr oposed controller is evaluated for perturbations in time delay, time c onstant and gain. The performance of the proposed controller is compar ed with that of the PID controller settings given by DePaor and O'Mall ey (1989). The robustness of the control system is theoretically also evaluated by Kharitonov's method (1978).