Handling and stability of 4WS vehicle based on reference model for yaw rate feedback control

With the development of traffic-net and the elevation of vehicle speed, the research of four-wheel steering (4WS) vehicle and control strategy comes under broad attention increasingly. In the paper, the dynamic characteristics of 4WS vehicle were illustrated. Based on the linear model of the tire, the linear two degree-of-freedom 4WS vehicle model was established. The idea and control arithmetics were put forward based on yaw rate of ideal reference vehicle steering model feedback control. With the software of Matlab, the dynamic performance of 4WS was compared with conventional 2WS at the speeds of 20 km/h, 60 km/h and 120 km/h. The simulation results show that this method can trail after the reference model better, and reach steering stabilization of vehicles at different speeds. At high speeds, conventional 2WS has overshooting and its stabilization time is 88.6% longer than 4WS. The simulation analysis shows that 4WS system control method can track ideal model yaw rate sensitively, and acquire a better handling stability, which lays a theory foundation for more experiments on practical vehicles.