High-performance semiactive secondary suspension of high-speed trains using negative stiffness and magnetorheological dampers

With increasing transportation speed, the excessive vibrations of high-speed trains (HSTs) have become a critical issue to be solved. This study presents an innovative semiactive suspension system consisting of a magnetorheological (MR) damper in parallel with a magnetic negative stiffness (NS) element. The proposed semiactive dampers, called MRNS dampers, are integrated into the secondary suspension of an HST to improve riding comfort. The MRNS design can effectively enhance the vibration mitigation performance of semiactive MR dampers and compensate for the performance gap between traditional semiactive MR dampers and active controllers (e.g. linear quadratic regulator (LQR)). The effects of the NS coefficient and control force weight coefficient are presented, and the optimal selections of these parameters are discussed with respect to the control performance and force tracking errors of the MRNS controller. Results indicate that the MRNS damper can satisfactorily emulate LQR force trajectories. Hence, the semiactive MRNS controller can achieve vibration suppression performance comparable to that of an active LQR controller.