Design of Internal Model Controller Using Novel Filter

It is known that, for internal model control of higher-order system in industry, the traditional PID control method and conventional internal model control is not ideal and the approach to approximating high-order system by lower-order system would introduce model error. To solve such problems, an internal model control method using Butterworth filter is proposed in this paper, which has ideal low-pass filtering characteristics. The improved Butterworth filter replaces the low-pass filter designed for conventional internal model controller so that the control system has better dynamic and steady state characteristics. Simulation studies show that the proposed method could effectively control higher-order system and it is robust against model mismatching.