Method for Picking up Rail Wavy Irregularities Based on Empirical Mode Decomposition Method
Xiubo Liu · Zhongguo tiedao kexue · 2006
Rail wavy irregularities are hided in track geometry irregularities.Rail wavy irregularities can be identified and picked up by the combined method between wavelet and Empirical Mode Decomposition(EMD) method.The signals below 1 m wavelength are filtered out from vertical acceleration of car-body and surface irregularities from track inspection car by using biorthogonal wavelet analysis.The remained signals of vertical acceleration of car-body and surface irregularities are decomposed by using EMD.This method can ensure that first Internal Mode Function(IMF) gotten by EMD includes all the rail wavy irregularities.Rail wavy irregularities picked up by this method are analyzed and compared.Different type of rails have different rail wavy irregularities.Rail wavy irregularities are pseudo-period irregularities whichose wavelengths are about 3 m.The shock of car-body is caused by rail wavy irregularities.The wavy irregularities rails should be restricted on the speed-up railway line and passenger special railway line.