Research On Stator Vibration Characteristics Of Ring-type Traveling Wave Ultrasonic Motor

The ultrasonic motor(USM) is a new kind of conceptual micro-motor ,which utilizes the converse piezoelectric effect of piezoelectric ceramic to make the stator vibrate within the ultrasonic frequency range, and acquires the movement and torque through the friction between the stator and rotor. It posses features such as small size, compact structure, high torque at low speed, quick response, light weight, low noise, no electromagnetic interference and direct driving etc. It has become research focus at home and abroad. It has broad application prospects in the aerospace, medical devices, MEMS fields. Because its history is short, the theoretical model and design method is not perfect, it should be studied deeply.In this paper, taking ring-type traveling wave ultrasonic motor as the research object, mechanism of the friction contact interface and the impact of stator structure to the work performance of ultrasonic motor is detailed analyzed. The main contents of the thesis are as follows:In the first chapter, the USM's developing history and present research state are systematically reviewed. The significance and the main research contents of this paper are pointed out based on the analysis of current problems.In the second chapter, piezoelectric effect, piezoelectric ceramics, the structure characteristic and operation mechanics of ring-type traveling wave ultrasonic motor are introduced, one-dimension vibration model of stator is established.In the third chapter, aimed at the friction interface of ultrasonic motor, the motion characteristics of particle on the contact interface are studied, the contact interface friction-driven model is established, and the relationship between the load and rotor speed is studied.In the fourth chapter, the vibration modal analysis of stator is carried out using ANSYS, the impact of the stator structure parameters on dynamic characteristics of the stator is studied, the separation of modal mixture is carried out, provided the theoretical basis for optimization and design of motor structure. The fifth chapter is the summary of this paper, the research results are introduced, and the problems remain to be further deeply studied are pointed out.