Semi-active yaw dampers in locomotive running gear: New control algorithms and verification of their stabilising effect

It is generally accepted that semi-actively (S/A) controlled dampers can significantly improve the behaviour of a road or rail vehicle. In the case of a railway vehicle, it is possible to increase comfort using S/A control of vertical or lateral secondary dampers. On another way, S/A control offers the possibility of solving a contradiction in the damping requirements for different driving modes, in the case of control of bogie yaw dampers. However, this case has not yet been sufficiently investigated. This paper deals with applying magnetorheological dampers with semi-active control in the locomotive bogie to reduce hunting oscillation. The magnetorheological bogie yaw damper design, new algorithms for its control and application on a complex multi-body locomotive model that simulates fast running on a real straight track are shown. An essential part of the paper focuses on the effect of the damping force level and damper force transient response time. The results have shown that using the semi-active control of the yaw dampers makes it possible to reduce vehicle body lateral oscillation by 60% and improve running stability for higher equivalent conicity and subcritical speed. The critical speed can be increased by more than 250 km/h. The efficiency of the proposed semi-active control increases with increasing damping force level and decreasing transient response time. The control is most effective under conditions of low equivalent conicity.