Estimation of modal parameters and their uncertainty bounds from subspace-based system identification

摘要: Subspace-based system identification methods have proven to be efficient for the identification of linear-time-invariant systems (LTI), fitting a linear model to input/output or output only measurements taken from a system. An overview of subspace methods can be found in [Benveniste and Fuchs, 1985; Benveniste and Mevel, 2007; Döhler and Mevel, 2012; Van Overschee and De Moor, 1996].During the last decade, subspace methods found a special interest in mechanical, civil and aeronautical engineering for modal analysis, namely the identification of vibration modes of structures from the eigenvalues (natural frequencies and damping ratios) and observed eigenvectors (mode shapes) of an LTI system. For Operational Modal Analysis, the identification of a structure under operation conditions, it is often impractical to excite the structure artificially, so that vibration measurements are taken under unmeasured ambient excitation. Therefore, identifying an LTI system from output-only measurements is a basic service in vibration analysis, see eg [Basseville et al., 2001; Peeters and de