Research On Motion Stability Of Driver-Vehicle With 4WS Closed-Loop System

The vehicle with four wheel steering system (4WS) is studied in this paper. The motion stabilities of vehicle with 4WS open-loop system and driver-vehicle with 4WS closed-loop system are analyzed. The main purposes of this paper are: 1. First, a two degree of freedom linear vehicle model with steering angle input is introduced. Then, the effects of driver are considered in the manipulate control by Guo Konghui's Driver Model. At last, the model and the state equations of driver-vehicle with 4WS are formulated. 2. The traditional vehicle open-loop system and driver-vehicle closed-loop system are comparatively analyzed based on motion stability theory of dynamics. Then, the motion stability of the vehicle with 4WS is studied when the steering ratios are different between front wheel and rear wheel. 3. By using unsymmetrical matrix perturbation method and dynamic system parameter sensitivity method, some inherent relations are revealed quantitatively on the motion stability of driver-vehicle with 4WS closed-loop system, while one or multiple vehicle parameters varied. 4. A optimization method is presented for solving eigenvalue problem with unsymmetrical interval matrices. And this method is applied in the study of driver qualification effects on vehicle motion stability. In conclusion, some inherent rules and relations of motion stability of vehicle with 4WS open-loop system and driver-vehicle with 4WS closed-loop system are revealed in this paper. It can direct the design of motion stability of traditional vehicle and the vehicle with 4WS. Thus, vehicle maneuvering characteristics can also be improved. The results of this paper also can be applied in the optimal design of vehicle dynamic control system.