Stability analysis of metro vehicles with adaptive suspension
The tradeoff between running stability and curving performance is an unavoidable issue in railway engineering. The occurrence of hunting motions in the later period of metro vehicles arise the requirement of increasing primary positioning stiffness, which is adverse to curving performance. The so called ‘hydraulic bushing’ possesses a soft stiffness at low frequency and becomes stiffer at high frequency. In this paper, the filed test for a metro vehicle with hunting motions is firstly introduced. Two main aspects are then discussed to propose possible solutions to bogie hunting instability. One is the wheel-rail contact nonlinearity, especially for the high conicity with negative slope, which is easy to produce bogie hunting instability. The other is to study the application of the frequency dependent suspension respecting to improve the bogie hunting stability.