- 學位論文
模糊卡爾曼濾波法於建築結構系統之參數識別
Identification Structures Parametric System using Fuzzy Kalman Filter
摘要
由於921集集大地震造成了重大的傷亡，使得建築物之耐震設計受到相當程度的重視。結構物的耐震設計必須考慮地震力作用下結構物的動力行為，而為了瞭解結構系統的動力行為，可以藉由系統識別的方法和技巧求得結構系統的動力模式和參數。 本研究主要是利用遞迴參數方法，有效利用地震資料之輸入輸出值可作為即時線上系統識別，稱之遞迴最小平方模型，優點在於不需保存過去資料，解決資料過多時運算量繁雜之問題，用於線上作業可即時校正系統狀態、參數及輸出量。由於地震資料的訊號通常伴有雜訊值會影響在識別結構物參數的準確性，利用卡爾曼濾波法( Kalman filer )降低雜訊對識別的影響，即時檢測預測值和實際值之合理值。 使用卡爾曼濾波器的前提下，要先對狀態矩陣與觀測誤差和量測誤差協方差矩陣型式設定初始值才可使用此理論。因此本研究將利用卡爾曼濾波器中的量測誤差項以加入模糊系統以提高估量測項的準確性。 最後分析三種案例：1.設計含雜訊訊號2.國家地震中心之三層樓鋼構架加裝圓棒型加勁消能器3.台東消防分隊大樓。來分析結構物受到地震力影響造成系統參數變化情況，由識別效果得知當主結構受到破壞會導致頻率遞減與阻尼比明顯上升。
並列摘要
Due to the great damage induced by the Chi-Chi Earthquake occurred in Taiwan on September 21, 1999; more and more emphases have been put on the earthquake resistant design of buildings. Dynamic behavior of building under earthquake should be considered in the process of design. In order to realize the dynamic behavior of structural systems, the dynamic models and parameters can be determined by system identification techniques. The purpose of this research is to be use recursive parametric method to develop the on-line system identification by input and output, which is called RARX model. The advantage of RARX model no past data is required and complex problem of computing can be solved. It revised systematic state, parameters and output data. Signals are usually accompanied by noise; it affects accuracy of the structure of parameters. Kalman filter method is applied to reduce the noise from the measured data and improve the identification. The accuracy of model objective was revised by inspecting on-line estimations and observations. One prerequisite for Kalman filter is that the information of systematic state, the process noise covariance and measurement noise covariance should set initial value. Therefore, the fuzzy system is used in this research to enhance the accuracy of noise approximation. Finally, the design of noise model, experiment of steel frame with damper and Fire Department building in Taitung are taken as three examples for analyzing parameter changed when building affected earthquake. The results showed that the damping ratio will increase when building structure is destroyed and the frequency decreases.