Simulation and experiment of a blind subspace identification method

• Published in: Journal of sound and vibration Vol. 311; no. 3; pp. 941 - 952
• Main Authors: Zhang, Zhiyi, Fan, Jiangling, Hua, Hongxing
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 08.04.2008; Elsevier
• Subjects: Applied sciences; Blinds; Blocking; Building structure; Buildings. Public works; Construction (buildings and works); Exact sciences and technology; Excitation; Fundamental areas of phenomenology (including applications); Identification methods; Physics; Robustness; Simulation; Solid mechanics; Structural and continuum mechanics; Subspaces; Vibration; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Metallic structure; Wind; Vibration; Stabilization; Frame construction; Subspace method; Blind identification; Spurious mode; Experimental study; Modeling; Contamination; Hankel matrix; System with n degrees of freedom; Covariance; System identification; Block matrix
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2007.09.051

A covariance-driven subspace identification method is presented to identify weakly excited modes. In this method, the traditional block Hankel matrix is reshaped to enhance identifiability of weak characteristics. The robustness of eigenparameter estimation to noise contamination is reinforced by the reshaped block Hankel matrix. An alternative stabilization diagram in combination with component energy index (CEI), which indicates vibration intensity of signal components, is adopted to separate spurious and physical modes. Simulation of a vibration system of multiple-degree-of-freedom and experiment of a metallic frame structure subject to wind excitation are presented to demonstrate efficacy of the proposed blind method. The performance of this blind method is assessed in terms of its capability in extracting weak modes as well as the accuracy of estimated parameters. The results have shown that the proposed blind method gives a better estimation of weak modes from response signals of small SNR and gives a reliable separation of spurious and physical estimates.