车载振动观测方案对轨道不平顺识别效果影响研究

Investigation on the influence of observation scheme of vehicle vibration on track irregularity estimation

轨道不平顺是列车振动的主要激励源,影响列车运营安全性和舒适性。轨道不平顺的快速、准确动态检测对线路的维修养护具有重要的指导意义。将车载振动响应作为观测量,采用卡尔曼滤波理论上可以实现轨道不平顺的识别。铁路列车车辆模型复杂、自由度多,车辆振动响应观测传感器数量和精度有限,具有较高精度和经济性的实用传感器布置方案还有待深入研究。为此,建立10自由度独立车辆仿真模型,推导其对应的状态空间方程,假定轨道不平顺满足随机游走模型,进而基于扩增卡尔曼滤波算法对轨道高低不平顺空间曲线进行了识别,揭示了轨道不平顺识别结果出现数值漂移的原因,提出基于集合经验模态分解的去漂移方法。通过数值算例验证了所采用的模型及算法的正确性。考虑传感器布置可行性设计了6种观测方案,对各观测方案下的轨道不平顺识别效果进行了评估。分析了车辆参数、车速和传感器噪声对识别效果的影响。研究结果表明:绝对位移观测量的缺失会导致不平顺识别结果出现漂移现象;采用3个及以上观测量组合方案的轨道不平顺识别精度较高;观测量中包含相对位移可增强长波不平顺识别效果,但降低短波部分的识别精度。实际车辆参数、车速与理论值的较小偏差仅仅影响特定波长不平顺的识别精度,信噪比与识别效果在全波长段上呈正相关。研究成果可为轨道不平顺识别的车载传感器布置提供指导方案。

Track irregularity is the primary excitation source of the running trains,impacting both operational safety and passenger comfort.Swift and accurate dynamic detection of track irregularities holds significant guidance for track maintenance and upkeep.Track irregularity can be estimated theoretically based on the Kalman filter method by taking the vibrational responses of the vehicle as observations.Owing to the complexity of the railway vehicle model and the limitation of the vibration sensors in quantity and accuracy,more investigations should be conducted on the practical sensor arrangement taking both accuracy and economy into account.In this study,a single vehicle model with 10 degrees of freedom was established,and the corresponding state space equation was deduced.The track irregularity was assumed to meet the random walk model so it can be estimated based on the extended Kalman filter.The reason of numerical drifting in the estimated track irregularity was discussed,and a method was proposed for eliminating the drifting phenomenon based on the ensemble empirical mode decomposition method.The accuracy of the present model and algorithm were validated through numerical examples.A total of 6 observation schemes were proposed considering the feasibility of sensor installation.Investigations were then made of the influence of different observation schemes on the estimated track irregularity.To validate the performance of the proposed method,numerical conditions with different variables were taken into consideration,including vehicle parameters,speed,and sensor noise.The calculated results show that the lack of the observation of the absolute displacements of the vehicle leads to drifting of the estimated responses of the vehicle.The observation schemes including three or more sensors generally give accurate estimation of the track irregularity.The observation of relative displacement within the vehicle has positive influence on the estimation of track irregularity of long wavelengths,but has negative influence on that of short wavelengths.Small deviation of actual vehicle parameters and speed from the theoretical ones only leads to estimation error of track irregularity in specific wavelengths.The signal-to-noise ratio of the measured vehicle response is positively correlated to the estimation accuracy in full wave band of the track irregularity.The findings in this study provide guidelines for arrangement schemes of on-board sensors for track irregularity estimation.