GA type IMC-PID control for pneumatic servo system

Abstract

This paper presents a novel control scheme in which IMC(Internal Model Control)-PID control is combined with genetic algorithms(GA). IMC tuning rules have a number of advantages for enhancing control performance. IMC can minimize disturbance and use only one tuning parameter. IMC based PID control is attractive for industrial users because it has all the advantages of the IMC. For more aggressive control, we decrease the tuning parameter(more rapid response); for more robust response, we increase the tuning parameter(slower response). Usually we design the tuning parameter by trials and errors. But it is not so easy to design an optimal parameter for a specific system, especially for a nonlinear system. On the other hand, in the last twenty years, GA is attracted as one method which gives us optimal answers for global search, optimization and machine learning problems. In this paper, we propose an intelligent control scheme in which IMC-PID is combined with GA. GA will get the optimal or “near optimal” tuning parameter on-line after some generations. The effectiveness of the proposed scheme is confirmed by experiments using the existent pneumatic servo system.