Analytical study and control of high-speed vehicle hunting stability with traction/braking torque

The lateral dynamics of railway vehicles are significantly influenced by traction and braking forces, primarily due to the saturation effects inherent in wheel-rail creep. This study establishes a dynamic modelling approach for railway wheelsets subject to traction and braking torques. It unravels the impacts of these forces on the stability of lateral oscillations, commonly known as hunting stability. An analytical method is employed to investigate the influence of traction and braking torque on the critical velocity required to maintain the stability of hunting motion. The results demonstrate the beneficial effects of traction and braking torque in enhancing hunting stability. Subsequently, an innovative strategy is proposed for maintaining the stability of hunting motion in high-speed vehicles. This involves applying traction and braking torque separately to the front and rear wheelsets of each bogie. The proposed method is then applied to a high-speed vehicle experiencing strong lateral vibrations under unstable conditions. The findings affirm the efficacy and safety of controlling hunting stability through interventions of traction and braking forces. This approach proves effective in mitigating abnormal vibrations arising from hunting instability in high-speed vehicles.