考慮非線性效應下懸臂樑輸入負荷估測之研究

Investigation of Input Forces Estimation of a Cantilever Beam Including the Consideration of Nonlinearity

This study proposes an inverse method to estimate input forces of nonlinear dynamic systems. The present estimation method is composed of the Extended Kalman Filter (EKF) and a Recursive Least Squares Estimator (RLSE). By using the inverse method, input forces acting on nonlinear structural systems can be estimated from measured dynamic responses. In this work, laboratory tests of input forces estimation of a cantilever beam with a lumped-mass on the free end are performed to verify the practicality and accuracy of the proposed algorithm. In the experimental work, the beam was excited by harmonic forces. The estimation results demonstrate that the application of the input force estimation method to nonlinear dynamic systems is successful. 本研究提出一套反向法可估測非線性結構系統之輸入負荷。此反向估測包括兩部份：無輸入項擴展型卡爾曼濾波器及遞徊式最小平方估測器。由非線性結構系統之動態反應，利用此反向估測法可估測出作用其上之輸入力。為驗證所提出反向估測之可行性及準確性，本研究針對一實際帶集中質量懸臂樑，在結構非線性特性較明顯的狀況下，進行簡諧輸入力的估測實驗。由估測結果可知，本研究所提出之反向估測方法可藉由非線性結構系統之動態反應，有效及準確地識別出輸入負荷。