| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 95 === This thesis applies active vibration control method by feeding back rate sensor signal to computer, where angular displacement of the platform can be obtained by pseudo-integration. Adaptive sliding mode controller is used for vibration suppression, where external disturbance to the pan/tilt platform is supplied by a Steward platform. In addition, the Lyapunov theorem is applied to have the asymptotic stability of the closed loop system with system parameters updated on line.
In the experiments, a Steward platform disturbs the pan/tilt platform in yaw and pitch directions. Over 20 dB vibration attenuations can be obtained in the pan and tilt platform each independently under pure sinusoidal excitation, whereas over 17dB vibration reduction is observed for simultaneously pure sinusoidal excitation. In the case under two-frequency sinusoidal excitations, over 10 dB vibration suppression is obtained for each independently excited pan and tilt platform, and over 9 dB attenuations for simultaneously excited pan/tilt platform. Therefore, the adaptive sliding mode controller proves to be effective in suppressing the low-frequency vibration of the pan/tilt platform and has superior performance than does the linear controller using the filtered-X LMS algorithm.
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