基于压电陶瓷平面内应变的多自由度超声波电机驱动电路研究

Driving Circuit for Multi-degree of Freedom Ultrasonic Motor Using in-plane Deformation of PZT Elements

介绍了一种新型基于压电陶瓷平面内应变特性的多自由度超声波电机,该电机通过两个平面内的弯曲振动模态的叠加实现转子绕Z轴的转动;并利用伸缩振动模态分别与上述弯曲振动模态叠加实现转子绕X轴和绕Y轴的转动。设计了一种基于直接数字频率合成器(DDS)原理的电机驱动电路,该电路利用在FPGA元件实现的DDS阵列产生四路正弦激励信号,并采用高压运算放大器进行功率放大。该驱动电路的特点是各路驱动信号幅值和频率及驱动信号之间的相位差均可以独立调整。电机样机的机械特性实验以及调节特性实验结果表明该驱动电路满足驱动基于压电陶瓷平面内应变的多自由度超声波电机的要求。

A new multi-degree of freedom ultrasonic motor （MDOF USM） using in-plane deformation of lead zirconate titanate （PZT） elements was introduced. The rotation around Z axis was generated by combining both in-plane bending vibration modes; whereas the rotation around X or Y axis was generated by combining the longitudinal vibration mode and one of the above bending vibration modes. A driving circuit based on direct digital synthesizer （DDS） theory was designed. The DDS array synthesized in field-programmable gate array （FPGA） part was employed to generate four routes sinusoidal actuating signals and high voltage power operational amplifiers were applied to amplify them. The amplitude and frequency of each output signal, and the phase between two of output signals can be adjusted independently. The driving circuit was tested by experiments on the prototype motor and results show the circuit is feasible.