A study on the design and characteristics of the high frequency resonant inverter for ultrasonic motor drive using fuzzy controller

Abstract

In the present paper, a fuzzy logic based ultrasonic motor (USM) is used in order to properly control the speed and phase difference for the elasticity and viscosity of a robot joint. The traveling wave USM is driven by two-phase sine wave signals, and the phase difference of the signals is usually selected to +90/spl deg/ and -90/spl deg/ meaning high speed and maximum torque of the USM. In this paper, we describe USM rotational speed characteristics at no load. The first phase difference is adjusted in the range from +90/spl deg/ to -90/spl deg/ by fuzzy controller as is the reached target speed.