Reasearch On Dynamic Behaviour Of High-speed Vehicle With Faulty Anti-hunting Damper And Semi-active Control Of Carbody

It's doubtless that the vibration problem of the high-speed vehicle carbody is highlighted as the speed of the vehicle improves continually.The anti-hunting damper is the critical parts of the suspension system of the high-speed vehicle.It is one of the critical factors that can guarantee the vehicle run at high speed.And the anti-hunting damper is very important to the vehicle dynamic performances,such as stability,ride comfort and safety.Therefore,the researchers have paid more and more attention to the research of the anti-hunting dampers of the high-speed vehicle.Based on this background,firstly,it has been analyzed that the effect of the oil leakage fault of the anti-hunting damper on the dynamic performance indexes of the high-speed vehicle.And then,in order to improve the riding quality,the semi-active suspensions based on the Acceleration Drive Damping(ADD)“on-off” control strategy and the Linear Quadratic Regulator(LQR)control strategy have been designed.Next then the control effect and characteristics have been analyzed.The main research contents in this paper are shown as follows:(1)On the basis of considering the temperature,pressure and percentage of the air in oil,the nonlinear oil stiffness model of hydraulic damper has been established.And the damping has been processed into subsection according to the opening and closing characteristics of the damping valve system of the anti-hunting damper.Finally,the equivalent model has been established,which consists of the nonlinear oil stiffness and subsection processing damping.On the basis of this model,the oil stiffness in high pressure oil chamber has been analyzed while the oil seal is worn from normal to failure.And then the change law of damping force can be obtained.(2)The trailer car of the high-speed vehicle is established in multi-body dynamic software Adams/Rail,which contains 62 Degrees of Freedom(DOFs).And the damping characteristics of the anti-hunting damper in the condition that its oil seal is worn continually is imported into the high-speed vehicle dynamic model.Then the dynamic performance of the vehicle,such as stability,ride comfort and safety of curve passing have been analyzed after simulation.(3)On the basis of the research of the passive suspension dynamic performance,in order to decrease the detritions of the consumable parts and improve the riding quality of the high-speed vehicle in the lateral vibration of the railway vehicle,a modified ADD “on-off” control strategy is proposed in this paper.The semi-active suspension is analyzed by means of the Adams/Rail-Matlab/Simulink co-simulation.The conclusion can be obtained by analyzing the simulation results: Although the ADD “on-off” control strategy can reduce the lateral dynamic indexes of the vehicle,It may cause the signals saltation of the dynamic indexes when the on/off switches at the track with big irregularity,which may influence the maximum of the simulation results.There may be the phenomenon that the maximum of the semi-active suspension results is bigger than that of the passive suspension.(4)With the vibration characteristics of the railway vehicle and the control strategy of the LQR controller taken into consideration,a simplified controlled model of railway vehicle lateral vibration is proposed in the design process of the LQR controller in this paper.There are only the critical indexes of the complex full-size railway vehecle system considered by means of this simplified model.In this way,the calculative efficiency can be improved and the coordinating process of the weighting coefficients of the controlled indexes can be simplified.And there is a little deviation between the results of the simplified model and the full-size three-dimensional model.The multi-indexes of the semi-active suspension based on LQR control strategy can be controlled simultaneously and the control effect are very obvious and steady.In addition,the control effect of the critical indexes can be adjusted subjectively.Therefore the LQR control strategy is very suitable for the multi-indexes control in the complex railway vehicle system.