关键词: 线性慢时变结构, 工作模态参数, 滑动窗, 邻域保留投影, 最小二乘广义逆

Abstract: To identify the operational modal parameters of linear slow-time-varying structures,a method based on Moving Window Neighborhood Preserving Embedding(MWNPE)algorithm was proposed.Based on the time freezing theory,the linear time-varying structures were discredited into a finite number of linear time-invariant structures by treating the non-stationary signals in each window as a stationary random sequence with fixed length window.In each window,the neighborhood preserving embedding algorithm was used to find the low-dimensional embedding of the displacement response data in the window,which corresponded to the response matrix of the modal coordinates.The modal natural frequency of the window was identified from the modal response matrix by single degree of freedom recognition technique.The transformation matrix was estimated by Moore-Penrose matrix inverse,which was corresponded to the mode shape matrix.Simulation results of three Degrees of Freedom(DOF)structure showed that the proposed method could effectively identify the operational modal parameters of linear slow-time-varying structures,and the identification accuracy was better than moving window principal component analysis and Moving Window Equivariant Adaptive Separation via Independence(MWEASI).

Key words: linear slow-time-varying structures, operating modal parameters, moving window, neighborhood preserving embedding, moore-penrose matrix inverse