Dynamic modeling and analysis of bundled linear ultrasonic motors with non-ideal driving.

To achieve larger thrust and higher power in applications, multiple linear ultrasonic motors are usually combined. However, in previous researches, the motion mechanism of bundled linear ultrasonic motors is not explained clearly. Most researchers focus upon the description of experiments and the interpretation of experimental results, therefore until now, the dynamic model of the bundled linear ultrasonic motors has not been well established. In order to obtain deeper physical insight into the motion principle and provide a theoretical basis for better control of the bundled linear ultrasonic motors, a dynamic model for bundled linear ultrasonic motors is established in this paper. In this model, the contact interface is simplified to be a single point contact model and the impact of the clamping part on the performance of motor is considered. Using this model, the output characteristics of the bundled linear ultrasonic motors are investigated by discussing the influence of some important factors including preload, exciting voltage and exciting frequency. Test results show the proposed dynamic model is able to predict the output performance of the bundled motors. Moreover, the proposed model is not only suitable for the researched motor, but also can be extended to other bundled linear ultrasonic motors.