行波型超声电机速度控制技术的研究

当超声电机的驱动器处于开环工作时，超声电机的转速与驱动频率之间的关系表现为时变的非线性；同时其正向和反向的速度特性也常不一致，这给超声电机的应用造成了很大的障碍。该文首先推导出行波型超声电机定子上的孤极传感器反馈电压与其转速之间的关系。据此，作者设计和制造了速度控制器。其次，针对行波型超声电机的正向和反向速度特性不一致的情况，提出一种正、反向速度平衡补偿算法，并用硬件实现了平衡补偿控制器。实验结果表明：在驱动器中添加这个速度控制器和平衡补偿控制器后，不仅使行波型超声电机的速度特性对指令电压具有非时变的线性关系，而且使它的正、反向速度特性具有良好的一致性。这一研究成果为行波型超声电机在我国的实际应用扫除了技术障碍，也为其他类型超声电机速度控制技术的研究提供了有效的途径。

Research on the Speed Control Techniques of a Traveling-wave-type Ultrasonic Motor

The relationship between the rotation speed of an ultrasonic motor (USM) and its driving frequencybehaves nonlinearly with time-variability, and which limits its practical applications. In this paper, we show theresearch on the speed control techniques of a traveling-wave-type ultrasonic motor. At first, the relation betweenthe rotation speed and feedback voltage from a sensor, which is a segment (isolated electrode) of the piezoelectricceramic element bonded on the stator of the USM, is derived. And a speed controller for the USM is designed andmanufactured. Secondly, aiming at losing balance between the CW and CCW rotation speed, a balancing compen-sation algorithm is put forward, and which is implemented with hardware. The experimental results show that af-ter putting the controller and balancing compensation controller into the driver, the speed of the USM possesses oflinearity and time-invariability with a command voltage, and the CW rotation speed of the USM have a better ac-cordance with the CCW.