The Research Of High-Speed Automobile Side-Wind Stability Under Virtual Environment

With the increase of expressway in our country, all kinds of automobile's speed are improved greatly. It is important to study the performance of high-speed automobile in side-wind disturbance. At present, a lot of automobile dynamics model had been researched, which based on bicycle model of 2 degree of freedom. The model is simple, has little parameter, and is easy to carry on theory analyses. But it regards the whole automobile as a rigid body, uses the linear tire model. Used to analyze the movement of the vehicle in side wind, can't reflect the movement of the automobile totally. An 8 degree of freedom dynamics model of automobile based on non-linear tire model (Grim model) is build in this thesis, and Set up a virtual analysis model Using Simulink, and receive the more satisfied result. On the basis of this, establish one ideal driver feedback models, which are used to investigate both conventional front wheel (FWS) and four-wheel steering (4WS) automobile during side-wind disturbance. Two different 4WS control laws were used. The first was an open loop control law (OL4) where the rear wheel steer angle was determined by the front wheel steer angle. The second was a closed loop law (CL4) where the rear wheel angle was determined by both the front wheel steer angle and the vehicle yaw rate. Simulation results indicate that the CL4 system significantly improves the driver/vehicle performance in response to cross wind disturbance. While, the OL4 system does not improve the driver/vehicle system performance in a side wind disturbance. Along with the development of CAE, many multi-rigid body dynamics software get extensive application. A virtual automobile model in side wind is build to offer swift and convenient method for studying the movement of automobile in side wind disturbance using ADAMS.