Comparative Study On Two Different Kind Anti-hunting Mechanisms For HSRS

The security of HSRS (High Speed Rolling Stocks) in very cold zone has been established by the international academic community as one of the important research topic. According to the structural features of European cars, there are two basic instabilities:the bogie safety stability margin is not sufficient and the stability robustness of HSRS is bad. Under the extreme climate, the HSR use will be the formation of the perturbation or disturbance for HSRS, like the snow-ice barriers which even cause the lateral-swung motion of motor suspensions completely frozen. Thus for the technical solutions of alpine bogies, it is necessary not only to solve two basic instability problems, but also to take full account of the uncertainty and complexity of the harsh service conditions. It can be seen from the contrast of two different anti-hunting modes that the lateral track-shift force of rear wheelset is sensitive to the anti-hunting in-series stiffness rather than the anti-hunting damping rate. Therefore, the anti-hunting absorption-band mode must be taken to make the positive and moderate technical countermeasures.With the perturbation or disturbance caused by the Alpine car use, from the view point of the stability robustness of HSRS, it is determined that choosing the best parameter configuration to ensure the safety redundancy of Alpine cars. According to the current Alpine bogie configuration parameters, the optimum economic speed is only300km/h, and therefore it is no longer the remaining margin to resist the effects of perturbation or disturbance. The speed limit policy of200km/h in winter is very correct and pragmatic. The in-site regulation stability analysis for the existing length coding bogies proved that there are still some problems like coach shaking phenomenon. For the HSRS use in very cold zone, these problems will be more obvious, which result in the so-called stability robustness. With the best parameter configuration, the best economic speed can be350km/h. Taking into account of the oil leak of anti-hunting dampers which caused by the low temperature perturbation, the best commercial speed reduced to300km/h in order to control the lateral track shift forces. In view of the uncertainty perturbations of new sachs yaw damper, the use of HSR in very cold zone should be advanced steadily, and realize the300km/h commercial use step by step.In summary, the yaw damping of carbody is one of the main technical features for the European vehicle. Thus, the higher the anti-hunting series stiffness, the difference in stability margin between the front and the rear bogie of the motor car is greater. Especially for the wheel-rail run-in period, the equivalent conicity is lower (0.166-0.23), and the rear bogie stability margin of motor car will become very bad, under this situation, any perturbation or disturbance will cause a momentary instability and therefore produce high-speed coach shaking phenomenon. Thus, for the current high-speed rail track, there exist the best economic speed, which coordinate the resolution of the two basic instabilities. Nevertheless, the best economic speed is a optimization trade-off between the nonlinear stability of HSRS bogies and the safety stability margin of the HSRS. Taking into account of the perturbation caused by the snow-ice barriers and the uncertainty perturbations produced by the characteristics of anti-hunting dampers, the commercial speed of300km/h should be advanced steadily for Alpine cars.The Subject research financial support provided by(1) The Project of National Key Technology R.&D. Program (2009BAG12A01).(2) The R.&D. Planning Project of the Ministry of Railway, China (Project No:2011J013-B)(3) And the Opening Research Foundation of National Power Traction Laboratory of Southwest Jiaotong University (Project No. TPL1102).