Study on Large Capacity Ultrasonic Motor Using Principle of Strain Wave Gearing

本研究针对结构紧凑、重量轻、功率大的电动执行器的发展，研制了两种不同于传统超声波电机工作原理的超声波电机，一种是采用多层压电器件，另一种是采用环形压电器件。研究结果如下：(1)利用高刚度、大输出功率的环形压电器件，设计并试制了一种谐振型压电电机(超声波电机)。此外，还对前期研制的多层压电马达进行了改进，使其具有更高的机械刚度和更好的特性，为澄清马达存在的问题提供了基础数据。(2)主电路及其控制电路…改进了矩形电流波形和滤波矩形电压波形的FET逆变器的更多回路，以获得更好的波形和控制灵活性。(3)改进了电机扭矩-转速测量装置，为改进电机可能提高的转速预留了空间。(4)针对采用环形压电器件的电机，试制了两种电机，并进行了比较。一种是使用不分割装置的电机，另一种是使用等分成6个部分的装置。结果表明，电机扭矩与转速的关系不受装置分离的影响，而受电机定子的机械特性的影响。(5)阐明了环形压电器件与电气端子接触状态对电机特性的影响。特别是，在分环型器件的情况下，触点层的厚度对特性有很大的影响，因此有必要使触点层尽可能薄。(6)发现在使用环型器件的情况下，由于器件中的功率损耗，较高的外加电压导致器件温度显著升高。需要对电机定子结构进行改进，以提高定子表面的切向速度，利用装置的大应力，而不是装置的大位移。(7)对于采用多层压电装置的电机，试验采用了一种与电机底座对称的新型结构，以增加电机的机械刚度，并有效地将装置的位移传递给电机定子。较少

In this study, aiming at development of compact, light-weight large power electrical actuators, two types of ultrasonic motors, whose operational principle differed from that of the conventional ultrasonic motors, were developed, one using multi-layr type piezoelectric devices and the other using a ring type piezoelectric device. In the proposed motors, the traveling waves were generated by the principle of the strain wave gearing and the bending wave and the rotors were driven mechanically by the friction force.The results of this study are as follows ; (1) A resonant type piezoelectric motor (ultrasonic motor) was designed and made on a trial basis using a ring type piezoelectric device with high stiffness and large output power. Moreover, the multi-layr type piezoelectric motor developed earlier was also improved for higher mechanical stiffness and better characteristics, and basic data for clarifying the problems of the motor were obtained. (2) The main circuits and its control cir … More cuits of the FET inverters with rectangular current waveforms and filtered rectangular voltage waveforms were improved for better waveform and control flexibility. (3) The measurement equipment of the motor torque versus rotational speed was improved making allowance for possible increase of the rotational speed by improvement of the motor. (4) In regard to the motor using the ring type piezoelectric device, two types of motors were made on a trial basis and compared. One was a motor using the device not divided and the other was that using the device equally divided into 6 parts. As a result, the characteristics of the motor torque versus rotational speed were not so influenced by the division of the device but by the mechanical properties of the motor stator. (5) It was clarified that the characteristics of the motor was influenced by condition of contact between the ring type piezoelectric device and the electric terminals. Especially, in the case of the divided ring type device, the characteristics were considerably influenced by the thickness of the contact layrs and, therefore, it is necessary to make the contact layr as thin as possible. (6) It was found that the higher applied voltage resulted in the considerable increase of device temperature due to the power loss in the device in the case of using the ring type device. It is necessary to reform the structure of the motor stator so as to increase the tangential speed on the surface of the stator by using the large stress of the device without the large displacement of the device. (7) In regard to the motor using the multi-layr type piezoelectric device, a new type structure which was symmetrical with respect to the motor base was employed in a trial basis in order to increase the mechanical stiffness of the motor and transmit the displacement of the device to the motor stator effectively. Less