Simplified circuit model of disk traveling ultrasonic motor

This paper puts forward a method of establishing equivalent circuit model of traveling wave ultrasonic motor by using 1/2 wavelength stator with the same vibration characteristics. Combined with the vibration mode characteristics of composite plate of stator, the method utilizes Hamilton principle to obtain precise solution of the simplified equivalent circuit. The model shows mechanism of ultrasonic motor and reflects an influence of non-axisymmetric vibration mode, tooth outline, anisotropy of PZT, etc. Using the method, various electric parameters corresponding to different vibration modes, such as static capacitance, dynamic capacitance, dynamic inductance, dynamic resistance, equivalent input impedance, etc., can be solved. Experiments show good agreement with theoretical results.