Deterioration rate estimation of high speed train bogie unit based on copula function

To evaluate the mechanical wear degree of key component of high-speed train bogie, an approach using copula function to evaluate damping degeneration ratio of yaw damper is proposed in the paper. Vibration signals of a certain high-speed train are obtained under different degeneration ratios. The vibration signal is decomposed by wavelet packet filters first. The marginal distribution function of the signal is fitted by generalized Gaussian distribution. The joint probability distribution between degenerate signal and the normal signal is computed by Gaussian Copula function. The mean of joint probability density function is extracted as the feature and the degeneration ration of target signal is evaluated. The vibration signals of different parameter degeneration ratio of high-speed train bogie yaw damper are used to do experiments using the proposed method and compared with the real degeneration ratio. Experiment results shows the error is within negative 3 percentages to 3 percentages at the speed of 200km/h, which verifies the effectiveness of the proposed degeneration ratio evaluation method.