Optimal-tuning PID controller design in the frequency domain with application to a rotary hydraulic system

In this paper a new PID controller design scheme that uses optimisation in the frequency domain is proposed for industrial process control. An optimal -tuning PID controller is designed to satisfy a set of frequency-domain per formance requirements: gain margin, phase margin, crossover frequency and s teady-state error. Using an estimated process frequency response, the metho d can provide optimal PID parameters even in cases where the process dynami cs are time variant. This scheme is demonstrated through its application to a rotary hydraulic system and its performance is compared with six alterna tive PID tuning rules. (C) 1999 Elsevier Science Ltd. All rights reserved.