A method of improving the resolution and torque of stepper ultrasonic motor

Experiments show that there is a limited pace in stepper Ultrasonic Motor (USM), and most of the work on high resolution of stepper USM are spread out above this limit. This paper presents a novel way of improving the resolution of stepper USM, which is based on the principle of Differential Composite Motion (DCM). This method also improves the torque of Stepper USM working in low pace, a higher resolution and larger torque of stepper USM could be obtained by this method in low pace.