Study On Composite Ultrasonic Linear Motor And Driving

As a late model of Micro-Actuator, Ultrasonic Motor, since its appearance, has been the hot spot of the research in the field of technology and engineer. The ultrasonic motor is a new type of micro-actuator which depends on the converse piezoelectric effect of the piezoelectric ceramic and frictional coupling of vibration. This breaks the conventional conception of Electromagnetic Motor, which depends on Pole Coil and Magnetoelectroelastic Media to transfer energy. Because of tis excellent performance, such as low speed high torque, fast response time, and etc., ultrosonic motor is considered as the micro-actuator of the best prospect.Seeking for new theories and new structures is one important direction of the research of ultrasonic motor. Though differences exist in the styles and functions of the ultrasonic motors that have been developed, the key component—the elastic vibration body is usually made of isotropic material. In order to produce the so-called"Elliptical Movement"that cause the motor to act, the combination of vibration patterns or the spatial distribution of exciting vibration points must be used. This would result in the complexity of the motor and the difficulty in the design and debug of the whole system. This thesis developed a sample linear ultrasonic motor whose vibration body was made of anisotropic composite, and its Actuating Mechanism, Material Characteristic, Finite Element Modal Analysis and Driving were studied theoretically and experimentally.Based on the analytical solution of the CFRP's vibration, the actuating mechanism of the composite linear motor was explained with graphs and the vibration body's micro-stress-state was analyzed first in this thesis. The Finite Element Method was employed to perform the modal analysis and a finite model of the composite material CFRP (Carbon Fiber Reinforced Plastic) was established. The finite modal analyse's conclusions had a vital theoretical guidance for the designing of the motor's vibration body and driving. Several phenomenons were summarized as follows: the simplist vibrating model at B(1,1) , two degeneration resonace frequencies at B(1,1) vibration modals, and reverse equivalent stress distribution during the actions at the two degeneration resonace frequencies. Through comparing the dynamic simulation of the CFRP with different carbon fiber angles, it was indicated that the carbon fiber angles of CFRP should be close-by 45-degree in order to gain a biggish adjustable range of bidirectional rate. According to the fact that two-resonant-frequency corresponded the CFRP's two-vibration direction, a driving combined with voltage regulation and frequency modulation was developed, which adopted PWM and Resonance Boosting Inverter driving technique. At last the temperature affection was analyzed in theory, and an automatic frequency tracking function was proposed.