| The ultrasonic motor (USM) is a new type motor that has beendeveloped since1980s, It is different from traditional electromagnetic motors in principle. Ultrasonic vibration is excited by the conversely piezoelectric effect of piezoelectric materials and magnified by the elastic body. And through the friction converts, electrical energy is converted to mechanical energy. There are a lot of advantages,such as fast response,low speed, simple structure, no electromagnetic interference andd high holding torque when power is off,which make ultrasonic motor have wide application prospects in micro mechanism, robots, precise instrument, spacecraft and automobile.USM has many patterns, and two important patterns are developed to be miniaturization or big torque. The Double rotor ultrasonic motor has a bright perspective for its big torque. On the base of searching and reading mass of reference, In this paper, Cylindrical Bar-Type Ultrasonic Motor with Double Rotors are studied from the aspects of the drive mechanism, design theory and frequency annexing.The main research results are summarized as follow:In chapter1, the development of USM at home and abroad is reviewed. The ultrasonic motor’s structure and classification are systematically summarized. Then, the Cylindrical Bar-TypeTraveling Wave Ultrasonic Motor is mainly introduced from its feature, development history and present situation.In chapter2, the basic theories related to USM are presented, such as the piezoelectric effect of piezoelectric ceramic and the bending vibration theory of girder, as a result creating the math-model of USM. Because the ellipse traveling is the key of the motor running, we analyzed the form of ellipse which is essential to the driving of USM.In chapter3, 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 ANSYS. And through ANSYS analysis test the working frequency of a motor.In chapter4, the separation mode electrical match method for the resonant frequencies of USM was presented. To avoid the vibration under non-working modes, inductors should be connected in series to the USM, which is driven by switched-supply power.In chapter5, a special driver circuits is designed based on SCM, which can regulate the phase and frequency. 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, And the output signal analysis and motor drive experiment, we found that the designed of the drive circuits are reasonable and reliable. |
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