A New System Identification Method Operated in the Pole Domain

Abstract

A recent article [1] showed that the poles and residues of responses could be easily obtained from those of the loadings and system functions. Following the same theoretical principle, a new system identification method operated in the pole domain has been developed and tested in this article. In this method, the poles and residues associated with the input signals and output signals were first extracted by using the multi-signal Prony-SS method. Sequentially, the system poles were simply the output poles minus the input poles. The remaining work was to compute each corresponding system residue, which in theory is equal to the output residue (at the system pole location) divided by a quantity obtained from the input function calculated at the system pole location in the Laplace domain. In the numerical study, a 5-DOF shear building model was chosen to demonstrate the effectiveness of the proposed method. Two kinds of loading were investigated: (1) a sinusoidal decay signal, and (2) a signal composed of two sinusoidal components. From both scenarios, one concluded that the proposed method could accurately identify the system poles and residues, and thus the corresponding system transfer function.