Identification of structural parameters by the weighted least square method based on wavelet packet transform

The least square method is a common structural parameter identification method, but how to improve the accuracy of the identification remains an important research topic. The Wavelet packet transform is an extension of the wavelet transform which provides a complete level-by-level frequency time decomposition. A weighted least square method based on the wavelet packet transform is proposed in this paper. The excitation and structural responses are transformed by orthogonal wavelet paceket and wavelet packet coefficients on various frequency bands are applied in the weighted least square method to identify the physical parameters. The weighing values are decided by the signal-to-noise ratios on various frequency bands. The numerical simulations show that the proposed method can improve the identification accuracy greatly and the accuracy increases by the level of wavelet decomposition.