A modified time domain subspace method for nonlinear identification based on nonlinear separation strategy

2018 ◽  
Vol 94 (4) ◽  
pp. 2491-2509 ◽  
Author(s):  
Jie Liu ◽  
Bing Li ◽  
Huihui Miao ◽  
Xiang Zhang ◽  
Meng Li
Keyword(s):  
Time Domain ◽  
Subspace Method ◽  
Nonlinear Identification ◽  
Nonlinear Separation ◽  
Separation Strategy

Analysis of Operating Deflection Shapes Based on Subspace Method

1997 ◽  
Author(s):  
Nobutaka Tsujiuchi ◽  
Yuichi Matsumura ◽  
Takayuki Koizumi
Keyword(s):  
Experimental Data ◽  
Time Domain ◽  
State Space Model ◽  
Measurement Data ◽  
Time Varying ◽  
Subspace Method ◽  
Identification Scheme ◽  
Space Model ◽  
Time Varying Systems ◽  
Frequency Components

Abstract In this paper, we propose the new method to identify the Operating Deflection Shapes (ODSs) from the measurement data of time domain. At first, we present the identification scheme of ODSs based on a state-space model. Then the scheme is extended to identify the ODSs adaptively for the time-varying systems by using the URV Decomposition (URVD). Proposed scheme is able to decompose the deformation of a structure under operating condition into the underlying superposition of well excited frequency components. This paper introduces the algorithm and shows the effectiveness of our proposed scheme applyed for both synthesized and experimental data.

A two-stage time domain subspace method for identification of nonlinear vibrating structures

2017 ◽  
Vol 120 ◽  
pp. 81-90 ◽  
Author(s):  
M.W. Zhang ◽  
S. Wei ◽  
Z.K. Peng ◽  
X.J. Dong ◽  
W.M. Zhang
Keyword(s):  
Time Domain ◽  
Subspace Method ◽  
Two Stage ◽  
Vibrating Structures

III-Posedness and Regularization Method for Nonlinear Identification Equations in Time Domain

2012 ◽  
Vol 166-169 ◽  
pp. 3282-3289
Author(s):  
Xian Zhong Xie ◽  
Feng Zhang ◽  
Yang Li ◽  
Yong Tan
Keyword(s):  
Least Squares ◽  
Tikhonov Regularization ◽  
Time Domain ◽  
Regularization Method ◽  
Least Squares Method ◽  
Structural Parameters ◽  
Nonlinear Identification ◽  
Calculating Method ◽  
Ill Posed ◽  
Damped Least Squares

The ill-posedness of nonlinear identification equation in time domain of structural dynamics system is studied and a new calculating method to weaken the influence of ill-posedness is proposed. Damped least squares method is an algorithm of Jacobian matrix positive-definable, which can obtain the solution of ill-posed nonlinear identification equation. But the solution is sensitive to the test noise of response in time domain of the structure. To solve the problem of instability of the solution, a new calculating method is proposed which combines damped least squares method with Tikhonov regularization method. First, the estimate of structural parameters is introduced to Tikhonov regularization function, and a more stable identification equation in time domain can be obtained. Second, the identification equation is solved with damped least squares method, and the iterative result is an approximate solution of the former ill-posed problem. The numerical example shows that the new method in this paper is efficient to solve the ill-posed nonlinear identification equation in time domain.

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