Analysis and design of digital dual-repetitive controllers

A design method of dual-repetitive controllers is newly proposed to reduce dual-repetitive errors which consist of dual dominant fundamental frequency components and their harmonics in the frequency domain. The proposed control system can save memory size and reduce errors faster than the conventional single repetitive control system with dual-repetitive errors. Sufficient conditions for the stability and error convergence of the proposed control systems are given. To show the validity of the proposed systems, computer simulation results are illustrated for a typical disk drive head positioning control system.