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  • 學位論文

第二路徑線上模擬FXLMS演算法於適應性振動控制

Adaptive Control of Vibration Using FXLMS Algorithm With Online Secondary Path Modeling

指導教授 : 周傳心
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摘要


本文旨在設計一套有效抑制結構振動之主動適應性控制系統,以減輕低阻尼之結構系統,在受共振頻率激振時所產生劇烈之振動變化,以免造成結構之破壞。 本文的控制器使用適應性濾波器,採用FXLMS演算法及線上第二路徑的模擬。其中使用的FXLMS演算法,因為實際環境造成系統擾動的激發源無法得知,也就是無法得到參考訊號。所以我們藉由使用FIR濾波器輸出回授和誤差訊號回授的疊加,作為參考訊號,再結合線上第二路徑估計的模擬,以連續自動地測量受控對象的轉移函數或狀態方程式。並與預期的動態特性進行比較,利用誤差值調整適應性濾波器的加權向量,補償受控對象轉移函數或狀態方程式的變化,使得輸出之回授控制訊號達到最佳化,達到抑制結構物振動之目的。 控制器使用Real-time windows target 在pc監控下進行運作,並搭配壓電訊號感測電路、訊號處理電路(放大、濾波)、訊號擷取電路(A/D、D/A)、壓電致動器驅動電路等結構,構成主動控制系統。 實驗部份,以懸臂梁作為結構系統,壓電材料作為感測器與致動器,對懸臂梁進行單模態與多模態控制實驗。實驗結果顯示前三模態的單模態實驗有20dB以上的控制效果,多模態實驗的控制效果較單模態差,也有10dB以上的控制效果,驗證了第二路徑線上模擬FXLMS演算法確實有效地抑制振動。

並列摘要


This paper studied the designing of active adaptive control systems to control the vibration characteristics of a structure. For low-damping structure systems, it will produce violent vibration to cause damage of structure when systems received the influence of resonance frequency. The paper used adaptive filter as the controller of systems. It adopt FXLMS algorithm and online secondary path modeling. And used the feedback signal of FIR filter and the feedback of error signal to produce reference signal. By the way of the reference(input) signal and the error signal adjust weight parameters to make the control force of the output reach optimum, and to suppress the vibration of the beam. The system controller is PC-based, using real-time windows target to implement the algorithm. In addition to the algorithm, the system collocates circuit of processing piezoelectric sensor、circuit of signal processing(amplify、filtering)、circuit of signal acquisition(A/D、D/A) and circuit of driving piezoelectric actuator to constitute active control system. Experimental results on control of vibration show that single mode reduces about 20dB and multimode reduces more then 10dB. So, it shows that the adaptive controller by using the filtered-X LMS control algorithm can reduce the structure vibration efficiently.

參考文獻


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