Self-oscillated ultrasonic stepping motor with function of angular displacement self-correction: nonaxisymmetric (2,1)-mode thin disk motor

This paper deals with experimental investigation of a self-oscillated open-loop driving motor using a slitted rotor and a nonaxisymmetric ((2,1)) vibration mode thin annular disk which has four projection teeth on its inner circumference. This motor is suitable for application to watches because it can be constructed in a thin configuration and the slitted rotor enables the self-correction of angular displacement. In the experiment, two types of self-oscillation circuits were investigated for suitable driving. The results were that the self-oscillated driving motor could be achieved by using an operational amplifier and some inverter IC elements. That is, the self-correction function of the angular displacement of a stepping motor was confirmed in the case of the nonaxisymmetric-mode disk motor.