Active yaw-damper control for carbody hunting instability in high-speed trains

Abstract

Carbody hunting instability in high-speed trains (HSTs), arising from low wheel–rail equivalent conicity, leads to pronounced lateral vibration and degraded ride comfort. Field tests and bench modal tests confirm that the abnormal vibration corresponds to a carbody upper-pivot roll mode at approximately 1.48–1.49 Hz. To analyze the mechanism and develop an effective suppression strategy, a simplified lateral dynamic model incorporating nonlinear wheel–rail contact is formulated. Additionally, four yaw-angle feedback control laws are designed based on linear and nonlinear bogie or carbody yaw-angle. The simplified model indicates that negative yaw-angle feedback effectively suppresses carbody hunting, with bogie-based feedback providing the strongest modal decoupling and amplitude reduction. To evaluate the control performance under realistic nonlinear conditions, a full-scaled vehicle dynamics model incorporating nonlinear suspensions and wheel–rail contact is established and coupled with a Simulink-based controller through co-simulation. The results show that all active yaw-damper strategies effectively suppress carbody hunting and improve ride comfort. Among them, nonlinear bogie yaw-angle feedback exhibits the best overall performance, reducing the rear carbody Sperling index by up to 51.6% while limiting carbody vibration amplitudes without increasing bogie lateral vibration. These findings demonstrate the effectiveness and practical applicability of active yaw-damper control for carbody hunting suppression in HSTs.