A single-mode bidirectional ultrasonic motor using first-order radial vibration mode of piezoelectric vibrators

A single-mode bidirectional miniature ultrasonic motor has been proposed, having advantages of compact structure, simple driving circuit and high torque. Two vibrators and their corresponding clamping structures are designed to realize the bidirectional movement. The bidirectional motion driven by the first-order radial vibration mode is achieved by exciting the two vibrators with a single-phase AC voltage in turn. The prototype with a diameter of 30mm and a height of 25mm was experimentally characterized, and a maximum torque of 0.11Nm was obtained in both clockwise and counterclockwise directions under a relatively low driving voltage of 120V
_pp
.