Research The Application Of Axle Box Acceleration In The Calculation Of Track Geometry Of Mounted Track Inspection Instrument

Track irregularity has an important impact on the safety of train operation.Traditional detection methods cannot meet the needs of daily detection of lines.As a new detection method,the mounted track inspection instrument makes up for the shortcomings of traditional detection.The mounted track detector solves the orbital geometry through the attitude angle,but it has shortcomings in the medium and short wave solution,and the noise has a great influence on the solution result.Considering the small size and easy installation of the accelerometer,the accelerometer is installed in the track detector,and the medium and short wave calculation results of the mounted track detector are corrected by the axle box acceleration.(1)Theoretical research on the detection of track geometry by mounted track inspection instrument.The principle of using the attitude angle to solve the orbital geometry of the mounted track inspection instrument is studied.The suitable wavelength range of the attitude angle solution for the track geometry is analyzed,and it is clear that it is not suitable for solving the short-wave track irregularity.The influence of periodic and random noise caused by vehicle itself or environment on the accuracy of attitude angle calculation is studied.(2)Research on the method of calculating short wave irregularity in the track by axle box acceleration.The coherence between axle box acceleration and short wave irregularity in track is studied.Based on the principle of axle box acceleration integration method,the influence of different wavelengths and vehicle speeds on the accuracy of axle box acceleration solution is analyzed.Combined with the simulation results,a short-wave and medium-wave track irregularity calculation method based on axle box acceleration is proposed.(3)Research on attitude angle signal denoising method based on axle box acceleration characteristic change.The characteristic changes of axle box acceleration caused by different noises caused by vehicle body itself and line state are studied,and sensitive features are extracted and applied to attitude angle signal denoising.The characteristic change of attitude angle caused by wheel out-of-roundness and joint rail gap is analyzed,and a periodic denoising method combining wavelet transform and filter is proposed.The generation mechanism and characteristics of random noise signals are analyzed,and a signal denoising method combining EMD and wavelet threshold is proposed.The two characteristic indexes of signal-to-noise ratio and root mean square error are studied,and the denoising effect is analyzed.(4)Application of Axle Box Acceleration in Solving Track Geometry Position with Track Inspection Instrument Field experiments were carried out on the Zhunchi Railway(Gaojiabu Station-Balipu Station).The internal and external coincidence accuracy of the unevenness of the measured axle box acceleration calculation is verified.The height irregularity amplitude calculated by the axle box acceleration is close to the detection result of the rail inspection vehicle.The research results show that the accuracy of the track geometry solved by the axle box acceleration-assisted mounted track inspection instrument meets the relevant technical requirements.