Precision Positioning System Of The Ultrasonic Motor Drive Control Study

The ultrasonic motor is a new type motor that has been developed in recent twenty years. It is different from traditional electromagnetic motors in principle. Ultrasonic vibration is excited by the conversely piezoelectric effect of piezoelectric materials and magnified by the elastic body. With the friction coupling, the rotation of the rotor or moving of the slider is generated. Low speed, high torque, simple structure, no electromagnetic, and high holding torque when power is off, characterize ultrasonic motor. All of these characters make ultrasonic motor promising in some special application areas in micro mechanism, robots, precise instrument, spacecraft and automobile.With the rapid progress of the ultrasonic motor and its appliance, it is necessary to research on driving circuit and control method. High efficiency driving source and experimental device have become a hotspot at home and abroad. This thesis introduces a precise position control method, by which high precise position control has been realized by the experimental hybrid transducer type ultrasonic motor. Driving electrical source of ultrasonic motor based on DSP also has been discussed in the thesis.The main work accomplished and creative achievements is summarized as follows:1. Introducing principle, the development history and characteristic of USM and analyzing development and problem of driving source and position control method of USM.2. In the thesis, the essentials of high resolution and stepping characteristic of ultrasonic motor in theory and experiment has been pointed out. Based on this characteristic of the motor, the paper discusses high precise position control strategy named stepping-position control method and the factors that influence position precision are analyzed. By the stepping-position control method, high precise position control (0.010 degree) has been realized by the experimental hybrid transducer type ultrasonic motor. The rule of choosing controls parameter also has been defined.3. Designed and completed two-phase resonant inverter for driving ultrasonic motor with MOSFET, the frequency and phase difference of which can be adjusted.Driving signal on MOSFET is PWM signal generated from TMS320LF2407 DSP. UC3842 controlled BUCK circuit has been used as DC power, the output of which can be adjusted. Because of this, the electrical source can drive the USM that have different voltage rating.