The active control of the lateral movement of a motor suspended under a high-speed locomotive

In order to improve the dynamic performance of high-speed locomotives, an active control method for the movement of a suspended motor is proposed, in which a damper is replaced by an actuator. A simplified mechanical model of the flexible suspension system is established to study its dynamics and create an active control strategy. Then, a multi-body dynamic model of the locomotive is simulated to obtain the conditions for optimal control. The results show that a smaller damping of the lateral suspension is conducive to improving the dynamic performance of the locomotive; the system has a theoretical optimum damping ratio of between 0.1 and 0.3. A small level of damping results in a large lateral displacement of the suspended system, which cannot be allowed to occur due to space limitations. The optimal control is used with the aim of reducing the lateral vibration amplitude of the suspended motor system and bogie frame. The active control of the suspension system improves the lateral dynamic performance of the locomotive and effectively limits the lateral displacement of the suspended system relative to the bogie frame. Compared with a passive suspension approach, the lateral forces on the wheelset are reduced by up to 25% at speeds between 140 and 180?km/h on straight track, and the nonlinear critical speed is increased from 390 to 480 km/h.