Self-regulating mixed damping control strategy for mitigating carbody hunting instability and vibration control in high-speed trains

With the large-scale operation and significant increase in mileage of high-speed trains in China, vehicle hunting instability has emerged as a critical challenge. The resulting carbody harmonic vibrations significantly impact the ride performance of the vehicle system. Field tests have shown that in the case of carbody hunting instability, the carbody exhibits low-frequency and large-amplitude lateral harmonic vibrations, which cause the Sperling index to exceed standard values and severely degrade the ride comfort. Currently, high-speed trains in China predominantly utilize passive suspension systems, which are inherently limited in their ability to mitigate carbody vibrations due to their fixed suspension parameters. To address this issue, a vehicle dynamic model with 50 degrees of freedom incorporating the modified Bouc-Wen magnetorheological damper model is established. The aim is to devise the self-regulating mixed linear continuous skyhook and groundhook damper control strategy (SR-MLSG). This strategy autonomously adjusts the damping forces to mitigate the carbody harmonic vibrations. The results demonstrate that, compared with passive dampers, the SR-MLSG control strategy can significantly mitigate the carbody harmonic vibrations when carbody hunting instability occurs. Specifically, the Sperling index and RMS values are decreased by 40.2% and 79.6%, respectively. Furthermore, during the stable operation of the vehicle, this control strategy not only enhances the ride performance of the train but also effectively suppresses bogie vibrations, thereby exhibiting excellent overall control performance.