Linear-type Ultrasonic Motor Based On The Rod Longitudinal Vibration Study

This project is supported by the National Science Foundation (No. 50807048).The ultrasonic motor (USM) is a kind of new driver micromotor,that transforms the mechanical vibration of stator at ultrasonic range to macro motion of its rotor or silder applying the converse piezoelectric effect of piezoelectric ceramics and friction action.A linear ultrasonic motor (LUM) has a special advantage in the drive and control of the precise devices, it has a broad application prospect in the high-tech fields, such as precise instrument and device, medical field, astronautics, robotics, and so on.This thesis aims at the realization of the LUM based on longitudinal vibrate mode of pole, and studies on its drive mechanism, finite element analysis, driving device, designing and experiment. The following are the chief content of this thesis:1,The definition and characteristics of the LUM are systematically introduced, the current research at home and abroad are studied and the purport and application prospect of LUM are pointed out. Discussed the characteristics of the piezoelectric ceramics and studied the operational principle of LUM.2,The project studied the mechanism of the linear ultrasonic motor based on longitudinal vibrate mode of pole.From a sequence input voltages signals, the excitation process of operating vibration modes is explained. Oval sport track of driving points is deduced in theory. Build up the vibrate mode of stator based on finite element method through analyzing its structure. Analyzed the structure parameter of stator applying finite element software, finding a way which can control the resonance frequencies, and finally turning them to be the same one.3,A new driver of the USM is designed according to characters of the drive of the USM, and discussed the operation of each part respectively. A feedback controlling circuit based on characteristic of impedance angle is designed according to working characters and structure of the linear ultrasonic motor.4,According to the working characters of ultrasonic motor, two kinds of frequency tracking technique of USM that based on the voltage produced in the isolate electrode and based on the phase difference between the driving voltage and electric current were Intensive studied, also the operation, characteristics and function of two kinds of tracking technique were analyzed and compared.5,Carried on an experiment research. A sample of the linear ultrasonic motor and driving and controlling power are manufactured. Carried on a related functional experiment to the linear ultrasonic motor and power, results show that the motor can stabilize working, and the controller can maintain the status of USM. Carried on an experiment research about two kinds of controlling method, validated the correctness of conclusion.