Repetitive control design for linear servo systems

Direct drive linear motors have particularly good potential for use with the next generation of machine tool feed drives, such as high speed machining, since they can increase machining rates and improve servo accuracy by eliminating gear related mechanical problems. In the paper, repetitive control is employed to design a servo controller for reducing the steady-state error due to the periodic commands. A repetitive control scheme which has a phase advance compensator in the repetitive control loop is proposed to improve tracking performance for repetitive linear motion. The repetitive controller of an experimental direct feed drive system is implemented in real-time with a digital signal processor