Robust Disturbance Observer-based Repetitive Control for Brushless DC Motors

Repetitive control (RC) is widely applied in rotational control systems including brushless DC servo motor (BLDC), since it can track periodic reference signals and reject periodic disturbances. However, RC cannot compensate aperiodic disturbances, friction, parameter uncertainties, backlash, and time delays. All of these uncertainties may lead to higher tracking errors. To overcome this issue, a series of novel RCs is developed to track the reference signal accurately and reduce the tracking error. The novel RCs can improve the performance of BLDC in hard drives, vehicles, air conditioning, robots and more. Subsequently, the efficiency is increased and the cost is reduced.