A three-step design method for performance improvement of robust repetitive control

This paper presents a three-step design method to improve performance of repetitive control systems. The performance is enhanced for rejection of high frequency harmonic disturbances by extending the bandwidth of low-pass filter Q in repetitive module. In this method, an interim feedback controller K\´ is designed firstly to ensure the realizability of the Q design in repetitive module. Then Q filter is designed to satisfy robustness stability of system. Finally the feedback controller K\´ is redesigned as K to guarantee overall system robustness performance. This method is referred as "K\´-Q-K" procedure and is applied to active vibration control of Hexapod. Simulation results demonstrate the improved performance by using the proposed approach.