Circle condition-based PID controller design considering robust stability against plant perturbations

This paper presents a novel proportional-integral-derivative (PID) controller design considering the robust stability against plant perturbations for the fast and precise positioning control of mechatronic systems. Since parameter fluctuations in plant mechanisms and/or actuators, due to temperature variations, aged deteriorations, etc., generally deteriorate the motion performance as well as the system stability, an improvement in disturbance suppression capability of feedback (FB) control system is a general and important index to provide robust properties against the fluctuations. In this study, therefore, a circle condition-based PID controller design considering the robust stability is presented as well as a genetic algorithm (GA)-based optimization process of a PID-type FB controller with resonance compensation filters, to balance a trade-off between the disturbance suppression and the system stability. Effectiveness of the proposed approach has been verified by numerical simulations using a laboratory prototype of galvano scanner.