Issues of optimality and computation has increasingly become an important research area in tracking problems of repetitive control. The control schemes in this book, termed as Optimal Low Computation Cost Schemes, bypass the original requirement of solving high order AREs by reducing the order of large systems into their low order counterparts. This is achieved either by a projection method or a low order scheme based on the spectrum analysis of the demand signal. Experimental tests on a software cam system and a servomotor motion control system demonstrated the effectiveness of the proposed...