Systematic modeling for free stators of rotary - Piezoelectric ultrasonic motors

An equivalent circuit model with complex elements is presented in this paper to describe the free stator model of traveling wave piezoelectric motors. The mechanical, dielectric and piezoelectric losses associated with the vibrator are considered by introducing the imaginary part to the equivalent circuit elements. The determination of the complex circuit elements is performed by using a new simple iterative method. The presented method uses information about five points of the stator admittance measurements. The accuracy of the model in fitting to the experimental data is verified by using the measurements of a recently developed piezoelectric motor and a well known USR60.