【摘要】 该文采用Hilbert-Huang变换(HHT)对时变阻尼自由振动系统以及常见的Duffing振动系统和Van der Pol振动系统进行参数识别。首先通过经验模态分解将振动信号分解为自由振动信号和强迫振动信号,通过经验包络法得到分解后信号的振幅包络线和瞬时频率。进而使用瞬时振幅及瞬时频率通过最小二乘法估计得到振动方程的各项参数。与小波识别结果进行对比,数值算例表明Hilbert-Huang变换可以有效地识别时变阻尼自由振动以及Duffing振动系统和Van der Pol振动系统的时变参数并且有较高精度。更多还原

【Abstract】 Parameters of time-varying damping systems and nonlinear vibration systems, such as the Duffing and Van der Pol vibration systems, were identified by the Hilbert-Huang transform(HHT) in this study. The nonlinear vibration signal was first decomposed into free vibration and forced vibration components by the empirical mode decomposition. Subsequently, the amplitude envelope and the instantaneous frequency of the decomposed components were computed by the empirical envelop method. Damping ratios and other parameters of the nonlinear vibration systems were finally identified by using the least square method. Compared with the results from the wavelet analysis, the proposed method is proven to be more effective through numerical simulations of three typical nonlinear vibration systems and is featured by a higher level of accuracy.更多还原