在行波超声波电机伺服控制中,电机需要低速运行和正反向转动。调压可以实现低转速控制,但通过单一调节驱动频率和电压不能改变定子行波的运动方向,因而电机转动方向无法改变。调节两相驱动信号相位差,在±π/间直接切换会造成在切换点转速的剧烈跳动。因此要想获得理想的伺服控制效果,采用驱动频率、电压(占空比)、相位差三种调节量分段调节,通过模糊控制算法,可以解决低转速控制和转速跳动问题。以直径60mm行波超声波电机为实例,通过转速、位置伺服跟踪控制对这种控制方法进行了实验验证。
In the servo control system, traveling-wave ultrasonic motor (TUSM) need work in low speed. The rotation direction of motor would be changed. Low speed control can be realized through voltage regulation. But the direction is unable to adjust by frequency or voltage regulation. Speed fierce vibration will be created, when the phase difference of two driving signals is simply switch between ±π/2 in the switching point. Through the fuzzy control algorithm, the speed vibration can be avoided by partition regulation of the three variables. A 60 mm-diameter TUSM is utilized in this research. The speed and position tracking servo control has carried on the confirmation to this method.