| Summary: | 博士 === 國立臺灣科技大學 === 機械工程系 === 98 === This paper proposes three intelligent precision control algorithms for overcoming the drawbacks of serious hysteresis behavior and highly nonlinear property for the dual-axes linear piezoelectric ultrasonic motor. The proposed control methods include the two-stage rule-based expert system, fuzzy logic and fuzzy sliding mode control. Optimal control parameters are determined by experiments without the need of complicated mathematical modeling. Position control performance for step response, sinusoidal and circular trajectories are evaluated and presented in time domain. The experimental results demonstrate that the proposed control methods are feasible and effective.
In addition, linear piezoelectric ultrasonic motors are often employed for positioning control at micro-nanoscale, and deviation from the original position may occur after repeated positioning. Hence, in this study, a novel automatic micro-nano alignment system using high magnification vision system coupled with a dual-axes linear piezoelectric ultrasonic motor was developed. The analytical algorithm of this vision-aided auto-alignment design makes use of real-time movements captured by CCD as inputs to obtain the difference between the fiducial mark and the target position. Alignment commands can then be fed to the two-axis piezoelectric motors to compensate for the positional difference. Both theoretical deductions and experimental trials have proved that the novel automatic vision-aided alignment system is robust and feasible for achieving precision to the micro-nanometer scale.
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