Digital control of a piezoelectric motor

A digital controller for piezoelectric motors was developed. The controller tunes the driving frequency in order to maximize the power transmitted to the motor. A maximum of power is absorbed when the resonant frequency of the mechanical and electrical part of the piezoelectric motor are equal. This frequency varies in the first place because of the applied force. The control method consists of comparing two values of the transmitted power, measured at different moments, and deciding as a function of the result whether the frequency should be increased or lowered. An analysis of the developed regulator is performed and suggestions for further development are given.