| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 105 === In precision positioning applications, high-bandwidth, high-stroke, and high-accuracy single-axis coarse fine positioning stages are often proposed and used in precision metrology and manufacturing applications, such as atomic force microscopy, optical focusing system, and lithography of IC industry. In comparison to single stage, coarse fine positioning stages offers potentially larger dynamics range and compatible accuracy. However, due to the coupling effect caused by the interaction between these two stages such as inertia force generated during motion, the dynamic performances are usually limited. As a result, it is desired to study the interaction between them and develop effective active control schemes to eliminating the coupling for improving the dynamic performance. In this dissertation, a single axis dual stage is designed and realized to serve as the platform for addressing the concern addressed above. This novel stage integrated a rubber bearing positioning stage as the upper and a compliant metallic positioning stage as the bottom components. The rubber bearing stage, driven by a voice coil motor, utilizes four sets of rubber pads for providing stiffness and stiffness adjustment using preloads. On the other hand, the notch-based bottom stage, in conjunction with a piezoelectric actuator, could effectively provide better loading capacity and stiffness stability. Through mechanics modeling and dynamic testing, the transfer functions of stage dynamics are established. PID controller design based on both Ziegler-Nichols (Z-N) tuning and loop transmission shaping (L.T.) methods are implemented and simulated by Matlab/SIMULINK before experiments. The steady state resolution and bandwidths of the upper stage achieved are 182 nm and 15 Hz with Z-N and 14 nm and 52 Hz with L.T design methods, respectively. On the other hand, the achieved resolutions and bandwidths are 46nm and 50Hz for Z-N and 23 nm and 120 Hz for L.T. deign methods. Meanwhile, the error motion of one stage induced by the other stage due to coupling is also studied. Through step response, it is discovered that the motion of bottom stage induced by upper stage can be effectively suppressed by control while the reciprocal combination is less effective. On the other hand, in the sinusoid tracking control experiment, the coupling amplitudes are effectively suppressed within the control bandwidth in both cases. The suppression of coupling effect is further improved after optimizing the controller design by considering the coupling dynamics and positioning-axis error. In summary, the control schemes are successfully developed for controlling the motion and eliminating the coupling of a self-designed single-axis dual positioning stage. The controller design methodology and the proposed varying-stiffness rubber bearing stage design should be very useful for effectively enhancing the dynamic performance of future motion stage design applied in precision metrology and manufacturing.
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