Research On Cylindrical Bar-Type Traveling Wave Ultrasonic Motor With Double Rotors

The ultrasonic motor (USM) is a new and special type motor based on inverse piezoelectric effect which has been developed since1980s.There are two process in the energy conversion of USM, one is that the electrical energy is transformed into vibration energy through electromechanical coupling, another is that the vibration energy is transformed into the kinetic. energy of the rotors. The invention of the USM made up for the deficiency that the traditional motor cannot be used in miniaturization and the environment with high-intensity magnetic field interference. And it also has lots of advantages:small volume with big torque, uninfluenced with high-intensity magnetic field, fast response, compact structure, etc. All of these characters make the USM have wide application prospects in micro mechanism, aerospace and automotive industry.On the base of searching and reading mass of reference, this project aims at the realization of the USM with two rotors based on two orthogonal bending modes of langevin vibrator, and studies on the driving mechanism, the modeling and optimization by FEM, the design of mechanical structure and driver system of this kind of USM. The following are the major research achievement and work of this thesis.First, this paper systematically summarized the developed history, current research and application of USM in domestic and oversea. And it also introduced the working characteristics, advantages and categorization of USM. According to the current research situation of bar-type USM, this paper posed its existing problems and shortage and clarified the research direction of this paper.Second, the basic theories related to bar-type USM are presented, including piezoelectric and bending vibration mode of the beam. The project studied the mechanism of this type USM and discussed the situation to generate stator surface travelling wave and particle elliptical movement. Combined the theory discussed above, this paper give the realization possibility of two rotors rotary motion. Third, this paper builds the FEM modeling of the USM stator, through which the conclusion that piezoelectric coefficient can influence the motor inherent frequency can be got and this has checked by software AN SYS. The influence of stator structure parameter for its performance and the place of piezoelectric ceramic plate are analyzed by software ANSYS. Combined this conclusion, we designed the sample of USM.At last, a special driver circuits is designed according to the sample USM. In the paper, the process for designed are presented. We also simulated the main feature of this driver, compared with the conclusion from experiment data, we found that the designed of the drive circuits are reasonable and reliable.