ウェーブレット変換を用いたがたを有する非線形系のパラメータ同定(機械力学,計測,自動制御)

概要

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In the present study, a new technique for parameter identification of nonlinear vibration system is demonstrated using Wavelet transform. The Wavelet transform is a technique which provides the time-frequency representation of analyzed signal. The transform can be expressed as an inner product of the signal under analysis with a family of translations and dilations of one basic primitive known as the mother wavelet. Unlike Fourier analysis which yields an average amplitude and phase for each harmmonic in a data set, the wavelet transform produces an instantaneous estimate or local value for the amplitude and phase. This allows detailed study of non-stationary time-dependent signal characteristics. The identification method is illustrated using single-degree of freedom nonlinear vibration system with gap support characterized by piecewise linear spring property which exhibits nonlinear restoring force and also by coexisting viscous damping and friction during contact. It is shown numerically as well as experimentally that the proposed method well identified the parameter of the present nonlinear system. It is also known that the asymmetricity of the gap can be detected from the signal plane of time history of free vibration which is transformed by the Wavelet.
2003-11-25