The Analysis And Control Research On High Speed Vehicle Response Characteristic Under Crosswind

With the ever increasing of traveling speed, the problem concerning crosswind stability of high speed vehicle has emerged. For automatic stability does not exist with all its meaning in vehicle dynamics, when the vehicle deviates from the travel route because of crosswind disturbing, it can't correct itself automatically, thus increasing the driver's workload undoubtedly, even no timely reaction can be done. So in this paper, the response characteristic of high speed vehicle under crosswind is studied, and control methods are proposed for improving crosswind stability of vehicle.The research situation of vehicle crosswind stability test utilizing crosswind generators both at home and abroad is retrospected. Based on the test data, vehicle dynamic response characteristic under crosswind is analyzed and validated.In the perspective of Four-Wheel-Steering control, 2-dof and 3-dof vehicle dynamic model considering crosswind is established respectively, and vehicle steering response characteristic is analyzed. Based on the decoupled vehicle model, control scheme and strategy of 4WS vehicle are designed, where scheme is active 4WS and strategy is model reference adaptive control. Adaptive control algorithm is derived from Lyapunov stability principle. Simulation results show that the active 4WS can effectively improve vehicle dynamic response performance and enhance vehicle stability under different kinds of crosswind and in different travel conditions.As a matter of fact, vehicle parameters are often indefinite or can be influenced by various kinds of factors. In order to enable adaptive controller to keep better control effect when the vehicle parameter changes, neural network is utilized to build model reference adaptive controller, which is applied to active 4WS. Simulation results are presented.Considering roll motion of vehicle body caused by crosswind, the relationship between suspension characteristic and crosswind stability is studied. Hydro-pneumatic suspension rigidity and damping characteristics are analyzed combining one project by means of experiment and calculation. Analysis show the feasibilities of adopting active or semi-active suspension technology to the improvement of vehicle crosswind stability.