Model Simulation And Testing Research On Traveling Wave Type Ultrasonic Motor

The ultrasonic motor (USM) is a new kind of conceptual electrical machine. Breaking through the principle of the traditional electro-magnetic motor, ultrasonic motors utilize the converse piezoelectric effect and the friction coupling operation of the stator/rotor to perform the energy conversion between the electric energy and the mechanical energy. The research of USM is related to many fields, and its history is not long. The profound research of the USM operation mechanism is exploring and optimizing, so the further study of the USM should be taken.In this dissertation, three methods are used to study the operation characteristics of the traveling wave type ultrasonic motor (TWUM), and some performance tests are done. At the last, the design method of two types of USM is introduced.The dissertation contains eight chapters. In 1st chapter, the USM's developing history, features, classification, application and present research state are introduced respectively, as well as the content and purpose of this dissertation. In 2nd chapter, the converse piezoelectric effect of ceramic is introduced. Simplified with the equivalent ring type plate, the lateral bending vibration and operation mode of USM's stator is presented. The operation mechanism of USM is also introduced in this chapter. In 3rd chapter, the finite element analysis (FEA) method is used to simulate USMs. The model analysis, harmonic analysis and impedance analysis are used to study the USMs'stator with 60mm and 100mm in diameter. The optimum design is applied to the structure of stator and rotor in USM with 100mm in diameter. With the optimum structure stator and rotor, the USM's operation performance is improved. In 4th chapter, taking into account the USM with 60mm in stator diameter, the contact model between stator and rotor is studied. In this model, the stator is simplified as an equivalent composite beam, and the teeth on the stator are also considered. In the end of the chapter, the motion equations of the rotor are combined with the contact model, and the 2D linear contact simulation model is established. By using that model, the operation performance of USM is calculated. In 5th chapter, with the assumed vibration model shape of USM stator, using the Hamilton energy variation principle, the complete dynamics simulation model of USM is established. According to the actual structure parameters of USM, the model parameters are calculated. By studying that dynamic model, the starting process is obtained, and the effect of pre-pressure and driving frequency on operation performance is also presented. In 6th chapter, the input impedance, starting process and the test method of USM's operation performance are presented. By using that method, the testing results are obtained and compared with the simulation results. In this chapter, the test of pre-pressure's effect and the USM micro-stepping characteristic is also introduced, and the test results are presented. In 7th chapter, the design and optimization of the cylinder stator 3-freedom USM and the piezoelectric ceramic linear USM is presented. And the structure dynamics correcting methods of the two types USM are brought forward. The last chapter is the summary of this dissertation.