Motion stability analysis of vehicle with four wheel steering system considering tire nonlinearity

Based on the model of driver-vehicle with 4WS closed-loop system considering tire nonlinearity, the nonlinear motion stability of vehicle with steering angle input was analyzed in this paper. From the point of view of system and control theory, some inherent relations of nonlinear motion stability were revealed quantitatively for vehicle with 4WS on different roads. The nonlinear motion stability analysis results of vehicle with 4WS were compared with those of vehicle with FWS at different speeds by some practical examples. The vehicle handling characteristics and motion stability can be improved through the motion stability analysis method of this paper. The vehicle with 4WS can also be optimized by using the results of the present method.