Analysis and Design of a Ring-type Traveling Wave Ultrasonic Motor

Ultrasonic motor, as a novel actuator, has attracted extensive attention for its advantages. Ring-type and disk-type ultrasonic traveling wave motors have the best controllability among all type ultrasonic motors. A ring-type traveling wave ultrasonic motor is designed and analyzed for a servo system in this paper. The ultrasonic motor is composed of three parts: stator, rotor and housing case. For detecting the speed and position of the ultrasonic motor, we designed the rotor with a double head shaft. One head of the shaft connects with a photoelectric encoder. The other head drives load. This paper analyzes the vibration mode of the ultrasonic motor stator in detail. Using ANSYS FEM software, we analyzed the vibration mode of the metal-piezoelectric ceramic composed plate in piezoelectric coupled field. Vibration mode (0,6) is chosen as working vibration pattern by analyzing and comparing. The resonant frequency of this vibration mode with 23406 Hz is calculated. Prototype USM runs about 25750 Hz actually