Abstract:

A broadband modal parameter identification algorithm is proposed for a multi-input multi-output (MIMO) system. The algorithm is based on the left matrix fraction description (LMFD) of the frequency response function (FRF). The modal parameters are achieved by using a least squares estimator so that the bad numerical conditions of the matrix can be avoided in the z domain. Considering the feature of left matrix fraction description, this article presents a construction method of the stabilization diagram by principal component analysis (PCA). It also dwells on the relationship between the classical poly-reference frequency domain (PRFD) and the proposed method. A simulation case of a GARTEUR model and an application case of an aircraft model are employed to validate the algorithm. The results show that good effect is achieved by the proposed algorithm.

Key words: modal parameter identification, left matrix fraction description, z domain, stabilization diagram, multi-input multi-output system, frequency response function