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Standing-wave ultrasonic motors (usm) have the advantages of small volume, light weight, fast response, high-precision position, power-off self-locking, no electromagnetic interference and vacuum adaptability etc. It has broad application prospects in the field of space laser communication. Because the driving force and power of single motor are limited, and in order to meet the requirement of torque margin in engineering applications, ultrasonic motors are usually used in pairs in laser tracking and pointing system. However, due to the preload of the motor, the inconsistency between production and manufacturing, and the matching between the driving circuit and the motor and so on, the resonance frequency among motors varies from hundreds of Hz to several kHz, which makes it difficult to realize synchronous control. In addition, the inherent nonlinear characteristics of piezoelectric ceramic also affect the high-precision control of the ultrasonic motor. In order to further improve the synchronous driving control performance of parallel motor, an ultrasonic motor driving control system based on high-performance Digital Signal Processor(DSP) and Direct Digital Synthesis(DDS) technique is designed in the paper. The frequency, amplitude and phase of the motor driving signal can be tuned independently and precisely in this design, and the open-loop characteristics of the ultrasonic motor are measured.
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