In practical rotary systems, the exogenous disturbances to be rejected often reveals significant repetitive characteristics. However, this fact is not explicitly taken into account in conventional servo controller design.
This thesis examines the rejection of periodic disturbances using a repetitive control strategy based on the internal model principle. A simplified repetitive control algorithm is suggested and applied to a VCR servo motor system which has inherent periodic tacking error. Since this algorithm is less dependent on the plant model and has simple structure, it is less sensitive to modeling error. The experimental results show that the suggested algorithm has a good periodic disturbance rejection capability and is effectively applicable to the case when the plant model changes due to different operating modes such as SP mode and/or EP mode in VCR.
