Adaptive Position Control of Ultrasonic Motors Using On-Line Parameter Identification with Variable Forgetting Factor Based on Fuzzy Reasoning

Abstract

Ultrasonic motor is a new type motor and it has an excellent performance and many useful features. Its simplified mathematical model, has not been developed yet. Moreover, its speed characteristics vary with driving conditions. Therefore, it is important to identify the speed characteristics of ultrasonic motor on-line in order to achieve the high-performance control. In this paper, the authors dervie a mathematical model of ultrasonic motor and propose position control based on the model using adaptive control. Moreover, we propose precise position control of ultrasonic motor using on-line parameter identification algorithm (recursively least square method : RLSM) with variable forgetting factor based on fuzzy reasoning. The effectiveness of proposed control scheme is demonstrated by experiments.