Dynamics Analysis And Design Of Three-freedom Ultrasonic Motors With Cylinder-type Stator

The ultrasonic motor (USM) utilizes the converse piezoelectric effect of piezoelectric ceramic, the energy conversion between the electric energy and the mechanical energy and the friction coupling operation of the stator/rotor to perform the motion of the motor. Comparing to the traditional electro-magnetic motor , ultrasonic motor has some features: high torque at a low speed, fast response, high holding torque when power is off, compactness in size, low noise, insensitive to magnetic fields and so on. USM has been used into civilian products and military devices such as industrial control, automobile , robot, aerospace fields.As a new type motor, the design method and theoretical modeling of USM are immaturity and need to be developed. Based on the past research, the design methods are discussed and dynamic character of three-freedom Ultrasonic Motors with cylinder-type stator is studied. The principal works and achievement of this paper are followed:First, the development, characteristics, application and classification of USM are systematically reviewed. The present research and question of multi-freedom ultrasonic motor with sphere rotor are summarized. The natural longitudinal and flexural vibration of the cylinder-type stator are analyzed for three-freedom Ultrasonic Motors invented by work group.Second, based on systematically reviewing the motion mechanics and locus of three-freedom Ultrasonic Motors with cylinder-type stator excited by two resources, final motion equations of the motor excited simultaneously by three circuits are deduced with geometric method and motion locus excited by three circuits are simulated. The expression is very valuable to the control of locus and position. Third, based on systematic generalizing design points of three-freedom Ultrasonic Motors with cylinder-type stator, the structure of motor is optimized by experiment , finite element computing and theory analysis. Experimental data are analyzed to find the shortage. According to this, the structure of motor will be further improving. A grip type three-freedom Ultrasonic Motors with two cylinder-type stator is invented to increase impulse between rotor and stator. Structure and motion mechanics of this motor are discussed. Experimental results demonstrate that USM of the type have bigger torque to other three-freedom USM.At last, the summarized work and the further research are reviewed.