Variable Step-Length Efficiency Optimum Control of Traveling Wave Ultrasonic Motor System

To achieve the operational efficiency maximization of ultrasonic motor system, this paper analyzes optimum control of the ultrasonic motor system’s efficiency including driving circuit, while the speed closed-loop control performance is ensured. Based on regulating characteristics of open-loop speed control and fuzzy control, two optimum control methods for regulating the changing step-length of driving voltage amplitude, to shorten the elapsed time of efficiency optimization process and to improve the general operational efficiency of motor system and the speed closed-loop control performance, are also analyzed. The effectiveness of the methods mentioned in this paper are reflected using experiments.