Two Degrees Of Freedom Of Self-study Of The Linear Ultrasonic Motor

Ultrasonic motor is a new micro-special motor which can be drived by the friction between stator and mover. The friction is produced by the ultrasonic vabrition of piezoelectric materials produced when electricity explode the piezoelectric material. Because of its principle is different from electromagnetic motor's, ultrasonic motor unique advantages such as compact structure, low speed high torque, power locking, anti-electromagnetic interference, and fast response. With development of science, traditional motors can not meet the needs. But this technology would be used better in precision positioning device, aerospace, satellite sensors, bio-medicine, household electrical applications, and so on.In this paper, a kind of linear ultrasonic motor will be studied, which can be moved by itself in two degrees of freedom. During design and research of this motor, the theories involved with ultrasonic motor are summarized. When the motor has been manufactured, its basic parameters are measured. Through a combination of theory and practice, a better understanding of ultrasonic motor design has been gotten.In the process of design, the analytical method and the finite element method are used and the operation mechanism of the motor is discussed, that prove the existence of elliptical movement of motor's top surface in theoretically. Meanwhile the electrical energy and power transfer mechanism are analysed, and the transfer model of motor's strain is established. In the paper, the core component of the ultrasonic motor is piezoelectric ceramics. So a preliminary description of the piezoelectric material, piezoelectric effect, and several important physical characteristics piezoelectric equation is made.During structural design, many researches on the relations between key dimensions and natural frequency of motor. The analysis shows that a group of almost the same frequency of the bending vibration modes and the longitudinal vibration mode, which not only provided a strong theoretical argument for the realization of paper's motor, but also can significantly reduce the drive circuit requirements. According to Hamilton principle, the motor mathematical model is build in the view of energy which is involved with mechanical vibration, elasticity, piezoelectricity and other related theories. It is an important attempt about modeling of thin motor.It is the same with other special motors that ultrasonic motor has been developed in a few years. There are many problems still exist when it is designed. It is sill need set up a sound system of design and theoretical analysis. And fiction is very important for ultrasonic motor which is a highly complex phenomenon, and affects many motor performance parameters. Accordingly, there is much work to do, and also have the value of in-depth study.