A Multi-DOF Ultrasonic Motor Using In-plane Deformation of PZT Elements and Its Driving Circuit

Due to the increasing number of DOFs of systems and the reducing the volume and weight of the devices, multi-degrees-of-freedom (DOF) actuators have become more useful in the field of robotics. And the general features of ultrasonic motors are also suitable for constructing a direct-drive multi-DOF actuator. So, a new multi-DOF ultrasonic motor using in-plane deformation of PZT elements is introduced in this paper. Then its working principle and requirement for driving circuit are analyzed. At last, a driving circuit is proposed accordingly which generates sinusoidal actuating signals with a FPGA part (a Direct Digital Synthesizer (DDS) array is synthesized in it) and amplifies them with high voltage power operational amplifiers. It is characteristic of independent adjustment of amplitude and frequency for each output signal and independent adjustment phase between any two of output signals. The circuit meets the requirement of the motor.