New improved on–off damping force control algorithm for modern hybrid-damper-based lateral suspension systems in railway vehicles

Pure semiactive suspension systems combine the advantages of passive and active suspension systems to achieve superior performance. The robustness of pure semiactive suspension systems remains limited under certain conditions, such as those involving power loss, actuator failures, or sensor failures. To address these problems, the present study developed a modern hybrid-damper-based lateral suspension system that uses a new improved on–off damping force control algorithm. This modern suspension system integrates a conventional passive suspension system with a semiactive magneto-rheological damper, while the new control algorithm generates a constant yield stress force or zero yield stress force for the damper, based on a vibration velocity-threshold of car body. The performance of the developed method was evaluated primarily using simulations with a quarter railway vehicle model developed in MATLAB/Simulink under harmonic oscillation of railway tracks. The simulation results indicated that within a low-frequency range below 3 Hz, the proposed method outperformed a conventional passive suspension system and a modern suspension system employing a skyhook control algorithm, with the car body acceleration produced with the proposed method in the quarter railway vehicle model being 53.79% and 6.7% lower than those produced with the other two systems, respectively. Moreover, a comprehensive evaluation was performed using a full railway vehicle model developed in SIMPACK, with a mass rapid transit route, track irregularities, and crosswind effects considered to replicate real-world operating conditions. In the full railway vehicle model, the proposed method improved passenger comfort and running safety, reducing the root mean square of comfort index by 21.14% and 15.47% compared with the conventional passive suspension system and modern suspension system employing a skyhook control algorithm, respectively, and decreasing the peak values of derailment coefficient by 13.86% and 13.03% compared with the conventional passive suspension system and modern suspension system employing a skyhook control algorithm, respectively. In conclusion, the proposed method demonstrates high ride quality, high safety level, and practical feasibility, offering significant potential for real-world applications. However, experimental research is needed to further validate our simulation results.