Research On Semi-active Control Methods For Yaw Damper Under Complex Boundary Conditions

During the long-term service of high speed railways,the bogies exhibit complex vibration behaviour under the influence of complex boundary conditions such as random excitation of uneven tracks and line transformations,which affects the stationarity,running stability and even safety of the high speed operation.The problems of wobbling and excessive wheel-rail wear in actual operation can be largely attributed to the adaptability of the traditional passive suspension,so it is necessary to carry out research on the theory and key technologies related to the semi-active control of yaw damper,taking into account the complex boundary conditions.This thesis analyses the impact of yaw damper on the stationarity of vehicle operation from the equivalent parameter model of yaw damper and complex boundary conditions,and discusses the impact of complex vibration behaviour on the operational stability and safety of high-speed operation under complex boundary conditions such as random excitation of track irregularities and line transformations,and finally proposes a control strategy combining with PID control and fuzzy control.The semi-active control of the yaw damper under complex boundary conditions is realized,which has certain engineering application value to guarantee the long-term service dynamics performance,speed enhancement and operation and maintenance economy of high-speed operation in China.The specific work is as follows:(1)Based on the analysis of the working principle and structure of typical yaw damper,the equivalent parameter models of two different yaw damper were constructed,and the optimal model was selected by comparing the calculation results of the two models,and the influence of the yaw damper on the stationarity of vehicle operation was discussed through simulation calculations.The results show that: along with the change of the characteristic parameters of the yaw damper,the superior stationary region in the low equivalent taper area changes faster,and the qualified stationary region in the high equivalent taper area changes faster;appropriately reducing the nodal stiffness of the existing anti-snaking damper is conducive to improving the stationarity of the vehicle movement.(2)Consider the random excitation of track unevenness and line transformation and other complex boundary conditions,and discuss the complex vibration behaviour of the vehicle on the operational stability and safety of high-speed operation.The analysis is based on the comparison of three kinds of representative track irregularities,and analyses the influence of random track excitation on the vehicle dynamic response at different operating speeds.(3)In view of the shortcomings of the passive suspension system,a control strategy combining with PID control and fuzzy control is proposed to realise the semi-active control of the yaw damper under complex boundary conditions;through the joint simulation of UM and Matlab/Simulink,the vehicle dynamic response is compared with and without the control strategy under complex boundary conditions,and the effectiveness of the semi-active control strategy is verified.The effectiveness of the semi-active control strategy is verified.