L1B2 Piezo Motor Using D33 Effect

Abstract:
In this study, we introduce a new first longitudinal and second bending mode (L1B2) type piezoelectric ultrasonic motor. A rectangular piezoelectric prism with two separate electrodes on one main surface and one uniform electrode on the other main surface was used as a vibrator of the motor. By applying two sinusoidal signals with a phase difference of 180 degrees, one to separate electrode and the other to the uniform electrode, a longitudinal mode was excited. Since the length and the thickness of the prism were selected with a certain aspect ratio, the generated longitudinal mode was disturbed by the second bending resonance mode in thickness direction where d33 coupling coefficient is effective. As a result, an oblique or a narrow elliptical motion with an angle to length and thickness directions on the friction element that is attached on one end surface was obtained. Due to the slim geometry of the vibrator, the motor can be scaled and operated with multiple of them in a parallel structure. The motor has a good controllability and a wide range of moving speed from 1.0 µm/s up to 1.0 m/s.