Research On Modeling Method Of Four Wheel Steering Vehicle

The purposes of this thesis are researching several methods to built mathematics model and establishing a useful nonlinear dynamic model of 4WS(four wheel steering) vehicles. The model should reflect the effects of main factors in practical structures on the vehicle motion. It will then show the physical meaning and make the people understand the physical nature deeply. Using the model the key points of vehicle dynamics can be highlighted.The main work of this thesis include:1) Several mature models of 4WS vehicle is analysed, and the compare of them is carried out, the results is stated;2) Using the momentum theorem of Newton dynamics system and the method of Lagrange Analytical Mechanics system, the four degrees of freedom dynamic model of 4WS is established. Then the multi-body dynamics model is established by ADAMS software. The movement of the model includes: yaw, slip, roll, pitching and the nonlinear of tires force;3) The dynamic simulation is carried out by this four degrees of freedom dynamic model of 4WS, the results is reasonable;4) Using the PID method to control this model, the effect of control is presented. Then, the control method of PID with BP network is analysed and brought forward.