Track Irregularity Diagnosis Based On The Vehicle Axle Box Vibration Information

Due to the impact of rail production process, poor rail joint welding grinding, wheel-rail impact force and non-standard track maintenance may result in the shortwave track irregularity. The shortwave track irregularity directly affects the running speed of the train and the life of locomotive parts, even threatening the safety of train. Thus it has great engineering and scientific significance for the security operation of urban rail transit to research rapid and effective track shortwave irregularity detection methods and techniques.The vehicle-track dynamic model established by SIMPACK was applied to the research of shortwave track irregularity recognition in this paper, and a shortwave track irregularity identification method was proposed based on the axle box vibration information of running vehicle. Summarizing signal characteristics frequency and the state of corresponding shortwave track irregularity through the processing and analysis the axle box acceleration. That is to recognize the type and state of shortwave track irregularity utilizing axle box acceleration. The main contents including:(1) The study of relationship between axle box vibration acceleration and shortwave track irregularity. Starting from the wheel/rail interactive force, study the effect of shortwave track irregularity on vehicle systems, introduce the vehicle lumped parameter simplified model, derive the relationship between the harmonic track irregularity frequency and the axle box acceleration frequency through the establishment of wheel-rail vertical kinetic equation.(2) Establishment and simulation of vehicle dynamics model. Established rail vehicle dynamics model using SIMPACK according to the online running experimental vehicle structure parameters, analyzing the changing characteristics of vehicle axle box vibration acceleration time and frenquency domain by adding harmonic-track shortwave irregularity to the simulation track, verify the relationship of the harmonic track irregularity frequency and the axle box acceleration frequency.(3) Shortwave track irregularity feature information extraction from complex track irregularity. Based on vertical profile irregularity of the fifth grade American track spectrum, adding harmonic-track shortwave defects to the simulation track by the method of interpolation, compared the vehicle axle box vibration acceleration before and after the changing characteristics. Hilbert-Huang transform was used to time-frequency analysis of the axle box vertical acceleration and verify the added shortwave track irregularity feature information.(4) The analysis of the measured axle box vibration acceleration based on the online running experimental vehicle. A vehicle axle box vibration acceleration acquisition system was designed to get the acceleration information caused by track irregularity when the experimental vehicle running. After preprocessing of axle box vibration acceleration, through time-frequency analysis of vertical acceleration signal of the axle box decomposed by EMD, extracted the vibration information caused by track irregularity. By contrast with the test sites, the track irregularity position could be effectively located and the shortwave irregularities within a certain degree can be detected.