The development of Torque Mirror Control Method for Driving Ultrasonic Motor

我们从事超声波电机（USM）的开发已经超过15年。当然，我们的兴趣不仅是提出大功率小型盘式电机，而且在伺服电机的最优控制系统的应用。到这个时候，USM被认为是一个艰难的驱动器，因为它既没有承诺长寿命也没有保持恒定的速度。我们已经开始了对脚的研究，发现几乎所有的研究人员和制造公司普遍采用的控制方法是不稳定和不正确的。他们未能将电机锁定在正确的共振状态，这导致缺乏稳定性和短寿命。在这项研究中，我们开发了完善的PLL（电机的电流锁相）驱动器，并同时实现了恒流或恒压控制器。在此电路的帮助下，我们测量了恒流模式下USM原型的静态特性，并发现了在相对较小的负载转矩下的简单而奇怪的减速现象，这有助于我们提出新的摩擦板滑动理论。我们还发现，只要在一定小范围的转矩负载下运行，电机的寿命几乎是无限的。在本报告中披露了我在基金期间的研究过程，并参考了我们以往论文的理论背景。这也基本上是重要的，即使这项技术没有应用到任何电机产品，现在，展示如何设计一个优秀的USM和实际控制电路板的细节。最后，我们希望本文的研究能够帮助广大研究人员提高电机的效率，并自行构建一个完善的伺服系统。

We have been involved in developing ultrasonic motors (USM) for more than 15 years. Our interest is, of course, not only to propose high-powered small disc motors, but also in the optimum control system as to the application for servomotor. By this time, USM was thought to be a tough actuator to drive, because it neither promised a long life nor kept a constant speed. We have started the research about the feet and found mat the methods of control, which are commonly adopted by almost all of the researchers and manufacturing companies, are unstable and incorrect. They failed to lock the motor to the correct state of resonance, which caused lack of stability and short life. In this study, we have developed perfect PLL (Current phase lock of the motor) driver, and realized constant current or voltage controller simultaneously. With the aid of this circuit, we were able to measure static characteristics of the USM prototype under constant current mode, and discovered the simple and strange phenomena of speed reduction under relative small load torque, which helped us to propose a new sliding theory of friction plate. We also found that, as for as operated in certain small range of torque load, the life of the motor is almost unlimited. In this report, me process of the study during the period of the grant is disclosed, and the theoretical backgrounds in our past papers are referred. It is also basically important, even if this technology is not applied to any motor products right now, to show how to design an excellent USM and actual control circuit board in detail. Finally, we hope it will help all the researchers to improve the motor efficiency and to build a perfect servo system by themselves.