A novel nonlinear system identification based upon Hilbert Transform

![CDATA[It is well-known that the vibration frequency of nonlinear systems is amplitude-dependency. For most damped systems, this characteristic results in the variation of the vibration frequency with time. To take advantage of this phenomenon, a novel system identification method by curve-fitting the instantaneous vibration frequency and amplitude is proposed for nonlinear systems in this study. Herein Hilbert Transform is employed to extract the instantaneous vibration frequency and amplitude from the measured responses. According to the relationships between the instantaneous information and structural physical parameters, structural physical parameters are estimated by the least-squares estimation. The combination of the instantaneous data in time domain and frequency domain will necessarily improve the accuracy of identification results. The proposed method is demonstrated by numerical simulations.]]