| Ultrasonic motor (USM) is a new type piezoelectric actuator developed during recent three decades. It converts electrical energy to ultrasonic micro vibration using converse piezoelectric effect. The micro vibration then drive rotators (or movers) to rotate (or straightly move) via friction after being resonant amplified and superimposed. Comparing to traditional electromagnetic motor, USM has advantages on simple structure, flexible design, large torque, low speed, fast response, high positioning accuracy, self-lock at power off, and without electromagnetic radiation. Therefore it can be applied widely in many fields, such as aeronautics & astronautics, optical instrument, robotics, semiconductor manufacture, medical apparatus, office automation, and auto industry. At present, almost all the practically used USM have only one degree of freedom (DOF) like linear or rotary movement, and the research on the structure and application on the multi-DOF USM is still in the early stage. This dissertation developed a novel multi-DOF plane liner USM and the relevant electrical match and driving system.A new type multi-DOF plane liner USM based on longitudinal and bending modes was proposed and its motion mechanism was analyzed. Driven by cross orthogonal horn, two channels of longitudinal vibrations and one channel of bending vibration superimposed on one single driving foot, and supply the trajectories for the motor, which could then move straightly in any direction on the xOy plane. Taking the driving foot as the research target, an analytical model of the rigid multi-DOF driving foot trajectories has been developed, and the liner driving input method in every directions of xOy plane has been analyzed.Comprehensive analysis was carried out on structure parameters of the actuator, and the parameters'influence tendency towards the eigenfrequencies was got to realize the longitudinal-bending vibration modal degeneration. By means of the finite element method, combining with the analytical model of the rigid multi-DOF driving foot trajectories, the simulation study on vibration mode of the duralumin driving foot was conducted. Eight driving points on the surface of driving foot was extracted and there trajectories under typical driving method were constructed. The consistency of driving effect under several driving methods was also analyzed.Based on the result of vibration modal eigenfrequencies'degeneration and FEM analysis, a multi-DOF USM with single vibrator driven by longitudinal-bending transducer was proposed and fabricated. The prototype experiment on impedance and vibration showed the validity and reliability of the theoretical analysis and simulation research. The fastest speed was 960mm/s and The most large output force was 100 N.The separation mode electrical match method for the resonant frequencies of USM was presented. To avoid the vibration under non-working modes, inductors should be connected in series to the USM, which is driven by switched-supply power. Meanwhile, since the USM is capacitive, its voltage would be interfered by resonant excited by the inductors. Through adjusting the values of capacitors and inductors, the separation mode electrical match method could arbitrarily obtain the necessary value of voltage to ensure the stability and security of motor, and guarantee the wave filtering effect at the same time.The USM driving control system based on digital signal processor was designed. The digital wave synthesizer was used as the signal generator, and the full-bridge inverter was used in power amplifier. The phase-adjust range is 0o~360o, and adjust resolution is less than 1o; frequency-adjust range is 15 kHz~150 kHz, and adjust resolution is less than 1 Hz. The output power is 500W.
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