| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 93 === This thesis focuses on the study of orientation control of a pan/tilt platform subjected to base excitation. Combination of an adaptive active vibration control and a vision system is done to form a vision servo system for suppressing vibrations of the pan/tilt platform. A CCD camera is mounted in the tilt platform for capturing an object coordinates, which can be disturbed from its center position due to base disturbances and which is then fed back to the computer. A control signal from the controller is sent to the servo motors in the pan/tilt platform hoping for constantly orienting the object in the center of the image plane.
For the controller design, adaptive feedback controls based on Filtered-X LMS algorithm, and self-tuning regulator, as well as a neural network are utilized for attenuating vibration from the platform base disturbances. Experimental results reveal that for single-frequency base disturbance, about 21.56 dB attenuation and 17.41 dB attenuation can be obtained, respectively, by using the Filtered-X LMS algorithm and self-tuning regulator for independent yaw or pitch control. However, for simultaneously yaw and pitch vibration control, less vibration reductions of 15.56 dB and 11. 57 dB are observed for using Filtered-X LMS algorithm and self-tuning regulator, respectively.
For dual-frequency base excitations, 15.56 dB and 10.0 dB attenuations are obtained by using the Filtered-X LMS algorithm and self-tuning regulator, respectively, for independent yaw or pitch control, whereas 10.05dB and 6.74 dB reductions are observed for simultaneously yaw and pitch vibration control. From these experimental results we can see the effectiveness of the adaptive feedback controllers for suppressing the low-frequency vibrations. Lastly, a series of fixed point disturbances is applied to the pan/tilt platform, the neural controller is shown to have the capability of re-orienting the object in the image center in about 3~5 seconds.
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