High-speed Train Gearbox Fault Diagnosis Based On Modified CEEMD And IMF Value Evaluation

At present,High-speed railway has been greatly developed,and safety has always been the main theme of high-speed railway development.As the main component of the transmission system,the gearbox bears the excitation from the wheel-rail and the car body,and the vibration environment is complex,which should be the key state monitoring object.The Empirical Mode Decomposition(EMD)based methods presented by Huang et al.,and the main members include Empirical Mode Decomposition(EMD),Ensemble Empirical Mode Decomposition(EEMD),Complementary Ensemble Empirical Mode Decomposition,(CEEMD).All of the EMD-based methods are self-adaptive methods for non-linear and nonstationary signals.EMD-based methods consider the local time scale feature of the signal,which means the frequency information or other prior information of the signal is not needed.EEMD and CEEMD are noise-assisted data analysis methods.These two methods have a great performance on the mode-mixing problem of EMD method,which is caused by the intermittence.Among these two methods,CEEMD has lower reconstruction error,and thus,CEEMD was used to decompose the gear vibration signal in this paper.Both EEMD and CEEMD need large ensemble trails to ameliorate the residue noise in the reconstruction procedure,and they all have a heavy computation cost.For online monitoring system,the efficiency of the algorithm is an essential part.Using EMD-based methods to decompose the signal can obtain several intrinsic mode functions(IMFs).The selection of the IMFs is an important part of the research work.A modified CEEMD method was proposed to reduce the computation cost.The reason of the feasibility of the improved CEEMD method is that the impact or the noise could be obtained as the first few IMFs,and after removing the impact or the noise component,the residue signal can be decomposed by traditional EMD method.Besides,an IMF value index is also carried out for IMFs selection.According to the results of the simulation study and high-speed train gearbox vibration application,the validity of the proposed methods is verified.