Position Control of an Ultrasonic Motor Using a Fuzzy Controller

Abstract

A fast and fine position control method of an ultrasonic motor has been already studied which uses phase shift input and applies a linear control system. However this method has a drawback in damage of the lining material because the rotor jumps slightly from the stator in an ultrasonic frequency in the neighborhood of a command position. So it is desired to cut down voltage input and to decrease the amplitude of the traveling wave after the coarse positioning is completed. This paper presents a new control method which uses not only phase shift input but also voltage input and varies them using a fuzzy controller. Besides a fast and fine positioning, prevention of abrasion of the lining material was achieved by applying this fuzzy control method.