Research On Secondary Suspension MRF Damper For High Speed Train

In recent years,with the rapid development of Chinese railway,the speed of high-speed train is also rising.The increase of the speed of the train will lead to hunting instability in the straight track.Therefore,the high-speed train is equipped with an anti-yaw damper in the secondary suspension.In order to improve the speed,it is necessary to increase the damping force of the anti-yaw damper,but if the longitudinal damping force is too large,the safety performance of the train will be affected when passing the curve.Therefore,the contradiction between lateral stability and curve negotiating is an urgent problem to be solved in the process of train speed-up.However,the conventional anti-yaw damper can't solve the contradiction between the lateral stability and the curve negotiating.MR damper has the adjustable damping characteristics,so using the MR damper to solve the above contradictions.In this paper,high-speed train secondary suspension anti-yaw MR damper is studied.The dynamics simulation software SIMPACK is used to set up the dynamics model of high-speed train,and the different track conditions are set up.The simulation is carried out in SIMPACK to analyze the train dynamics performance under different working conditions,and according to the simulation result,the anti-yaw optimal damping value is gain,thereby the range of MR damper's damping force is determined.The working mode of the MR damper is the flow shear mixing mode.According to the calculation formula of the damping force of the hybrid mode MR damper and the damping force range of the MR damper,the parameters of the magnetic circuit structure of the damper are determined.Calculate the magnetic circuit structure of MR damper by ANSYS software,and optimize the magnetic circuit structure.In order to make the damping value of MR damper to be adjusted in real time according to the actual operation of the train,the semi-active control is applied to the train suspension system to control the MR damper.In this paper,a kind of switchable fuzzy semi-active control is proposed,which takes the vertical displacements in the center of the vehicle as the control algorithm's switchable index and automatically adjusts the damping of the anti-yaw damper so that the train can get a higher damping value when running in the straight track,the critical speed of the train is increased;When the vehicle running in the curve track,MR damper is switched to a lower damping value to ensure the curve passing performance of the train;The fuzzy control is used on the straight line and the curve line respectively to make the damping coefficient of the damper variable.Through SIMPACK-MATLAB co-simulation analysis,it is found that switching fuzzy semi-active control can greatly improve train lateral stability,improve the curve passing performance of trains,and can better adapt to the line with different curve radiuses.It effectively alleviates the contradiction between the lateral stability and the curve passing performance in the speed raising process of the high-speed train.