A novel multi-degree-of-freedom thick-film ultrasonic motor

摘要

This paper describes a new multi-degree-of-freedom (MDOF)nultrasonic motor that comprises few parts and is based on low-costnthick-film technology. Conventional ultrasonic motors using bulk leadnzirconate titanate (PZT) or thin-film PZT layers are relativelynexpensive at the present time. Thick-film printed PZT technologynprovides the opportunity to reduce the costs of ultrasonic motors. Tondemonstrate the feasibility of this approach, an ultrasonic motor wasnfabricated from alumina using thick-film printed PZT actuators. Thenthick-film PZT and electrode layers were printed on a thin aluminanplate, and a tiny cylinder was mounted at its center. This cylindernmagnifies the lateral displacement of the stator, holds the sphericalnrotor, and transmits the driving force to the sphere. Three bendingnvibrations, B22, B30, B03, of the platenwere applied to rotate the sphere. Sufficient displacements for rotatingnthe sphere were obtained near the resonance of B22 bynapplying an excitation voltage of 200 V peak-to-peak via a three-phasendrive circuit. Rotations in three orthogonal directions have beennobserved by controlling the phase of the driving signal to the PZTnelectrodes, and a MDOF ultrasonic motor was successfully realized