For the worn state of the wheel, metro vehicles often suffer a serious carbody swaying issue, which causes the lateral stability of the vehicle to exceed the limit and affects the ride comfort. An experimental test was carried out on this investigation to study the carbody swaying of the metro vehicle. The field results show that the vehicle system vibrates at around 2.5 Hz in the lateral direction, which leads to the low-frequency swaying on the carbody. In order to explore the formation mechanism of the carbody low-frequency swaying and its relationship with the geometry matching of wheel-rail contact, measured rail and wheel profiles are employed to present a comparative analysis with respect to the initial contact geometry. A multibody dynamic railway vehicle system is established further. Time-domain simulations state that the 2.5 Hz vibration on the carbody belongs to the natural frequency of the vehicle, and the amplitude is larger for the measured wheels than that of the standard wheel profiles. By using the root-locus method, it can be determined that the 2.5 Hz vibration corresponds to the upper swaying mode of the carbody. With the increase in the wheel-rail equivalent conicity, the hunting frequency of bogie increases gradually, which converts frequency with the upper swaying frequency of carbody and leads to carbody low-frequency swaying.

中文翻译：

---

基于轮轨关系的地铁车辆低频摇摆机理研究

对于车轮的磨损状态，地铁车辆经常遭受严重的车身摇摆问题，这导致车辆的侧向稳定性超过极限并影响乘坐舒适性。在该调查中进行了实验测试，以研究地铁车辆的车身摇摆。现场结果表明，车辆系统在横向方向上以大约2.5 Hz的频率振动，这导致车身上的低频摆动。为了探究车身低频摇摆的形成机理及其与轮轨接触几何匹配的关系，采用实测的轨和轮廓对初始接触几何进行了比较分析。进一步建立了多体动态铁路车辆系统。时域仿真表明2。车身上的5 Hz振动属于车辆的固有频率，被测车轮的振幅大于标准车轮轮廓的振幅。通过使用根轨迹方法，可以确定2.5 Hz的振动对应于车身的上部摇摆模式。随着轮轨等效锥度的增加，转向架的摆动频率逐渐增加，从而将频率转换为车体的较高摇摆频率，从而导致车身低频摇摆。