Compound Speed Control of Ultrasonic Motor Using Two Variables

Abstract

In order to obtain more stable speed response, this paper designs a compound speed controller for travelling wave ultrasonic motor. The controller uses two variables, frequency and voltage amplitude, as the controlled variables. Among them, the frequency controller finishes the correction of larger speed error, and the voltage amplitude controller is used to accomplish the fine-tuning of speed error. The problems such as the jumping phenomenon in speed response, and saturation of voltage amplitude, are solved by this control strategy. Experiments show that, the control strategy is effective, and the speed control response is good.