Research On Semi-active Control And Hardware In Suspension System The Loop Test Of High-speed Train Secondary

In China,high-speed trains have the characteristics of high continuous running speed,long distance,complex and changeable track line conditions.Therefore,the dynamic problems of trains during long-term service are particularly prominent,especially the severe vibration of the car body,frame hunting instability,abnormal wear and deterioration of ride comfort.These problems not only affect the passengers’ feelings,but also threaten the safety of the train,shorten the service life of the train and increase operation and maintenance cost.In view of these practical operation problems,in order to improve the dynamic performance of the train such as ride comfort,running safety and stability,a series of theoretical simulation and experimental research are carried out based on the semi-active suspension technology of magnetorheological(MR)dampers.The specific research work mainly includes the following aspects:(1)The mechanical experiment analysis of the MR damper used in the thesis is carried out.On the basis of mastering a large number of test data,an improved hysteresis model is proposed to solve the problem that the existing hysteresis model can not better simulate the damping force under non identification excitation conditions,especially under high frequency conditions.Through theoretical simulation and experimental verification,it is found that the improved model can adapt to various working conditions,and especially under the working conditions with high excitation frequency,the error rate is significantly reduced.(2)The improved model of MR damper is applied to the model of a high-speed train,and the semi-active control simulation of secondary lateral damper is carried out.Two control strategies,Displacement-Velocity(DV)control strategy and Acceleration-Displacement-Velocity Direction(ADVD)control strategy,are used respectively to improve the ride comfort and running safety.On this basis,a coordinated control strategy is further proposed,which comprehensively considers the safety and ride comfort of the train,makes up for the shortcomings of the single control strategy,and improves the comprehensive dynamic performance of the train.(3)The influence of passive control,DV control and ADVD control on the dynamic performance of the train under the tread wear conditions is analyzed by considering the measured wheel tread under different operating mileage,and the influence of passive control,DV control and ADVD control on the wear performance and the rolling contact fatigue characteristics of the wheel under the wear conditions is also studied.The results show that the change trend of train dynamic performance with operating mileage under the semi-active control strategy is basically consistent with that under the passive control.At the initial stage of the lathe repair cycle,with the increase of tread wear,the ride comfort and safety of the train and other dynamic indicators are significantly reduced.In the middle and late period of the lathing repair cycle,the vehicle dynamics index slowly increases with the increase of wear depth.On the whole,semi-active control has weakened the critical speed of the train to a certain extent,but has significantly improved the ride comfort and safety of the train.In addition,the wheel wear and rolling contact fatigue index under DV control and ADVD control are lower than those under passive control,which indicates that these two control strategies are conducive to extending the lathing cycle and wheel service life.(4)The hardware in the loop experiment system of MR dampers is built for a quarter vehicle model and a seventeen degrees of freedom lateral vibration model.The experimental research on passive control,sky hook damping(SH),DV and its hybrid control,SH-DV,is carried out.The influence of the system time delay on the control effect is analyzed,and the energy consumption of the MR damper under each control strategy is calculated.In addition,the control effects of the control strategy under different track excitations and different equivalent conicities are also studied.The research results show that the SH control is sensitive to the time delay,and the larger the time delay,the worse the control effect.The DV and SH-DV control have strong resistance to the time delay,especially the DV control,whose control effect will not deteriorate with the increase of time delay,has the strongest stability and the lowest energy consumption.In a word,under different track excitations and equivalent conicities,semi-active controls can reduce the lateral vibration of the car body,and the DV control strategy proposed in this thesis is the best.(5)The particle swarm optimization Linear Quadratic Regulator(LQR)control method is used to control the secondary lateral damper and yaw damper simultaneously,so as to suppress the overall vibration of the train.The influence of mass parameters,suspension stiffness parameters,equivalent conicities and running speeds on the control method is analyzed.The research results show that the control mode can reduce the car body vibration and frame vibration at the same time,that is,improve the ride comfort,safety and stability of the train,comprehensively improve the dynamic performance of the train,and the stability of the control effect is strong.The research work is oriented by the actual demand,highlighting the application innovation,and provides a specific research scheme for solving the relevant dynamics problems of trains in the long-term service process.The paper enriches the semi-active control theory,expands its relationship with vehicle dynamics,and provides theoretical support for the feasibility of intelligent suspension system on high-speed trains.