Research On The Detection Method Of Rail Corrugation Based On Vibration Acceleration Of A Vehicle Axle Box

Metro,as the main artery of urban rail transit systems,not only has significant features such as large traffic passenger volume,safety and quickness,but also has a low carbon emission and is friendly to the urban eco-environment.It has become an irreplaceable means of transportation in people's daily travel and work life.However,after subway vehicles run for a period of time,rail corrugation will also appear on the rail,which is an academic problem for experts and scholars for nearly one hundred years.The corrugation on the rail is mostly short wavelength corrugation,but it will directly affect the life of locomotive and track components,reduce passenger's comfort and may even endanger the safety.Therefore,before systematic study of rail corrugation,how to quickly and efficiently detect and identify the corrugation has important guiding significance for the safe operation of urban rail transit systems.This article regards the axle box of the vehicle and the wheel pair together as a rigid body.The accelerometer was installed on the axle box.If the accelerometer is installed on the vehicle body,the vibration signal of the corrugation vibration was weakened by the first and second shock absorber suspension systems.Unlike the accelerometer of the vehicle body,the vibration impact caused by corrugation can be directly reflected in the vibration acceleration signal on the axle box.Therefore,based on the principle of the inertial reference method,the corrugation value can be obtained by integrating the vertical acceleration vibration signal of the axle box twice.The acceleration signal of the axle box contains not only the information of corrugation,but also other noises and irrelevant information,and the low frequency component that causes integral saturation since the installation of accelerometer was not vertical and temperature changed.Therefore,before the integral calculation,the EMD autocorrelation energy was applied to discriminate the noise components and constructed a new wavelet threshold function to preprocess the signal.Then pass the high-pass filter to remove the low frequency components,and design the integral filter to integrate the processed signal.Finally,to ensure the detection accuracy,the integration result was filtered by a high-pass filter to select the needed wavelength corrugation.The corrugation waveform calculated using the acceleration of the axle box through this detection method was compared with the actual rail corrugation waveform measured in the field.The results showed that the two waveforms were consistent in the changing trend,and can well agree with each other,and the wavelengths and wave amplitudes were also close to each other.Therefore,based on the principle of the inertial reference method,the result of the twice integration of the acceleration signal of the axle box using this detection method can be applied to extract the parameters of a rail corrugation.