STATE-SPACE FORMULATION - A SOLUTION TO MODAL PARAMETER-ESTIMATION

As an alternative to Fourier techniques based on transfer function fitting, modal parameters identification methods derived from a state space formulation of the dynamic equation have been recently studied and developed. This formulation leads to the solution of the modal problem via multi-dimensional ARMA model parameters identification. In this paper, the transition from the dynamic equation to the ARMA model is described and the algorithms of identification are explained, for the very common case of uncontrolled and unmeasured excitation. These techniques, the qualities of which have been established during extensive processing of offshore structures measurements, have been generalized to more complex excitation models such as those of turbo-alternators. Several examples illustrate these different application domains. © 1991.