A robust speed control architecture for ultrasonic motor

Abstract

Ultrasonic piezoelectric motor is an important system component in integrated mechatronics devices working on extreme operating conditions subjected to multi-disturbance. Due to these disturbance, robustness of the mechanics/electronics/control interfaces must be taken into account in the motor design. In this paper, a cascaded H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¿</sub> controller for a travelling wave ultrasonic motor (TWUM) is considered for wave, torque and speed loop control. To eliminate the nonlinearity, a simple causal model of the TWUM is used. Then, an H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¿</sub> synthesis procedure is implemented in order to obtain a good compromise between environmental robustness and motor's performances. Finally, simulation results demonstrate the effectiveness of the proposed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¿</sub> robust controller in the presence of multi-disturbance.