Analysis of a linear piezoelectric motor driven by a single-phase signal

A new linear piezoelectric motor is presented called the semi-elliptical ultrasonic motor. The composite structure of the stator is formed by two multilayer piezoelectric actuators clamped in an elastic body. The linear ultrasonic motor using normal vibration and tangential vibration modes of a semi-elliptical shape stator was fabricated and studied in this research. The geometric design of the stator has been computed with the help of the finite element analysis. In dynamic analysis, the semi-elliptical stator is analyzed by the impedance analysis method. Then, the equivalent circuit model is established to describe the relations between the system parameters and the dynamic characteristics of the motor. Based on the model, it can be explained theoretically why the piezoelectric motor can be driven by a single phase signal.