Single-Phase-Drive Standing-Wave-Type Rotation Ultrasonic Motors Using Piezoelectric Ceramic Hollow Cylinder

Piezoelectric ceramic hollow cylinders can be utilized to fabricate high-resolution rotation ultrasonic motor. 2 types of standing-wave motor based on coupled tangential-axial (TA) mode and longitudinal L-mode have been studied by using finite element method. The simulated results show that hybrid-mode motor (using both TA3 and L1 modes) has a greater mechanical output than that of single-mode motor (using only TA3 mode). A prototype motor of TA3-L1 hybrid modes has been fabricated using a piezoelectric cylinder with dimensions 20 mm OD, 16 mm ID, and 8 mm length. The measured resonance frequencies are close to simulated results. When driven by single-phase 206 kHz 60 Vpp continuous voltage, the motor has no-load speed of ~ 400 rpm, and stall torque of ~ 0.016 Nm. When driven by pulsed voltage, the motor exhibits a minimum step angle of ~ 20 μrad.