ADAPTIVE FEEDFORWARD CONTROL FOR POSITIONING SYSTEM WITH PROGRESSIVE WAVE TYPE ULTRASONIC MOTOR

This paper considers the use of an adaptive feedforward controller for a positioning system with a progressive wave type ultrasonic motor. T he parameters of the feedforward controller are adjusted by an adaptat ion algorithm, the objective of which is to make the feedforward contr oller a mathematical inverse of the motor. The error between the desir ed output and actual output is used as the adaptation error signal as well as the input to the nonadaptive feedback controller. After the ad aptive process is completed, the input to the motor is no longer suppl ied by the feedback controller but by the feedforward controller. The stability of the proposed adaptive control system is analyzed and its effectiveness is tested by experiments.