Linear stability analysis of a high-speed rail vehicle concerning suspension parameters variation and active control

Abstract

An Eigen root analysis is fulfilled for a high-speed rail vehicle concerning suspension parameters variation and active control using a simplified lateral-dynamics-intended model. The model is verified to be capable of reflecting the modal features of both carbody suspension modes and hunting modes. Subsequently, the effects of suspension parameters and the active yaw damper (AYD) on the vehicle modes are examined with various wheel/rail conicities. It shows that the frequency of hunting motion does not linearly increase with the vehicle speed but saturates to a value over 300 km/h. The crucial influential suspension parameters of the vehicle modes include the series stiffness and damping coefficient of the yaw damper, the longitude positioning stiffness on the wheelset, the series damping of the lateral damper, and the lateral stiffness of air springs. Sky-hook damping/stiffness control of AYD helps to increase the modal damping for bogie hunting concerns. For a large conicity of 0.37 case, a minimum of 400 kN·s/m is suggested for the damping control and 10 MN/m for stiffness control. Moreover, the damping control would adequately relieve the carbody hunting with a conicity of 0.11, and the stiffness control still works fine even with an extremely small conicity of 0.07.