Improvement of curve negotiation performance in intercity EMUs based on active steering wheelset

With the rapid development of intercity railways in China, issues such as wheel rail wear and excessive lateral forces during the negotiation of small-radius curved tracks have emerged. This paper proposed a method of integrating Electro-Hydrostatic Actuator (EHA)-based active radial steering dynamic modeling. The method integrates vehicle dynamic modeling, fractional-order Proportional-Integral (PI) control, and wear analysis. An EHA model integrating permanent magnet synchronous motors, gear pumps, and hydraulic cylinders was developed in Simulink. To address the poor curve-negotiation performance of conventional passive bogies, two EHA configuration schemes (longitudinal and lateral arrangements) were proposed based on theoretical analysis. Parameter analysis has been conducted, and the longitudinal EHA configuration has been demonstrated to be superior in the simulation environment. The results show that active radial steering technology significantly improves curve-negotiation performance through optimized wheelset alignment, with the longitudinal EHA configuration achieving superior reductions in attack angles, wear, and lateral forces. The longitudinal EHA arrangement demonstrates superior performance in suppressing wheelset attack angle and comprehensive wear control. Under standard conditions, it reduces wheelset attack angle by 35% and wear number by 30% in a small radius curved track. This technology enhances operational safety and reduces maintenance costs, providing critical technical support for efficient intercity railway operations.