基于希尔伯特-黄变换的地铁整体道床局部脱空识别

Identification of Local Disengagement in Metro Monolithic Track Bed Based on Hilbert-Huang Transform

为探讨一种基于车轨实时振动的地铁整体道床局部脱空的快速检测方法,通过对脱空发生前后的车轨敏感振动信号进行希尔伯特-黄变换(HHT),从变换谱中提取信息帮助识别整体道床局部脱空长度及起点位置。研究结果表明:1)车体、转向架和道床的竖向加速度对地铁整体道床局部脱空最为敏感;2)对这3种竖向加速度进行HHT变换后发现,道床竖向加速度的HHT变换谱难以直接判断整体道床局部脱空,而车体竖向加速度和转向架竖向加速度的HHT变换谱在局部脱空区域具有显著变化,可根据HHT变换谱的能量值变化幅度定性判断整体道床的局部脱空长度;3)当列车行驶到脱空区域,车体竖向加速度和转向架竖向加速度的HHT频率谱线将出现显著波动,结合列车速度以及脱空情况下HHT变换谱频率曲线极小值所对应的时刻,可判断出整体道床局部脱空的起点位置。

To develop a rapid detection method to study the local disengagement in metro monolithic track bed,the Hilbert-Huang transform(HHT)is applied to the sensitive vibration responses obtained before and after the local disengagement of the monolithic track bed.Subsequently,crucial information is extracted from the transform spectrum to identify the location of local disengagement.The results reveal the following.(1)The vertical accelerations of the carriage,bogie,and track bed are most sensitive to the local disengagement in the monolithic track bed.(2)By applying the HHT to the three kinds of vertical accelerations,it is observed that it is difficult to use the HHT spectrum of the vertical acceleration of the track bed to identify the local disengagement of the monolithic track bed,but that of the carriage and the bogie varies significantly near the local disengagement region.The length of local disengagement can therefore be identified qualitatively according to the variation of the energy amplitude of the HHT spectrum.(3)The HHT spectrum curves of the vertical acceleration of the carriage and bogie fluctuate significantly.Thus,the starting point of local disengagement can be determined by considering the speed of the train and the local minimum point of frequency curve in the HHT spectrum.