Ultrasonic motor is a new type motor and it has many useful features. This motor, however, has large speed ripple which arises from inherent natures caused by its driving principle and structure, and it is a significant problem in view of precise sp...
Ultrasonic motor is a new type motor and it has many useful features. This motor, however, has large speed ripple which arises from inherent natures caused by its driving principle and structure, and it is a significant problem in view of precise speed control. In this paper, we pay attention to periodicity of the speed ripple and reduce the speed ripple by repetitive control with variable learning factor based on fuzzy reasoning. The effectiveness of proposed control scheme is demonstrated by experiments.