PARAMETRIC IDENTIFICATION OF MECHANICAL SYSTEMS USING SUBSPACE ALGORITHMS / IDENTIFICAÇÃO PARAMÉTRICA DE SISTEMAS MECÂNICOS USANDO ALGORITMOS DE SUBESPAÇO

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Parametric identification of mechanical systems is one of the main applications of the system identification techniques in Mechanical Engineering, specifically for the identification of modal parameters of flexible structures. One of the main problems in the identification is the presence of noise in the measurements. This work presents an analysis in the presence of noise of some of the time domain methods applicable in modal parameters identification of linear time-invariant mechanical systems with multiple inputs and multiple outputs (MIMO), using as base the state-space model typically used in Dynamics and Vibrations. The subspace algorithms involved in this study are distinguished for the use of the singular values decomposition (SVD) of the data, obtaining ortogonal subspaces of the modes associates to the system and of the modes associates to the noise. Other complicators in the identification process that will be explored in this work are: flexibility and low damping. The techniques are compared using the state-space model of the Mini-mast structure developed for NASA Langley Research Center and simulations are made varying the level of noise in the data, the damping and the flexibility of the structure. The problem of identification of structural parameters (mass, stiffness and damping matrices) also is studied, the characteristics and limitations of the used algorithm is analyzed. As example of practical application, an experiment was made to identify the modal parameters of a flexible rotor and the results are discussed.

ASSUNTO(S)

flexible structures subspace algorithms analise modal experimental modal parameters sistemas lineares linear systems estruturas flexiveis experimental modal analysis vibracoes system identification identificacao de sistema parametros modais algoritmos de subespaco vibrations

ACESSO AO ARTIGO

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