Joint Optimization And Simulation Research Of 4WS Vehicle Handling And Stability

Based on 4WS vehicle open-loop model and driver-4WS vehicle close-loop model, vehicle handling and stability are studied. Through changing the vehicle's structure parameters, the handling and stability are jointly optimized. Further more, the 4WS vehicle's control strategy is also studied. The main research tasks of this paper are:1. A 2-DOF linear vehicle model is founded. In this paper a combinatory evaluation index based on the existing handling evaluation index and stability evaluation index of the open-loop model is put forward. Considered the factor of the velocity, a new combinatory evaluation index of the vehicle's handling and stability is set up. Through changing the vehicle's structure parameters, the handling and stability of the open-loop model are jointly optimized.2. The state equation of the driver-4WS vehicle close-loop system is deduced. Based on the existing handling evaluation index and stability evaluation index of the close-loop system, and considered the factor of the velocity, this paper puts forward a new combinatory evaluation index of the vehicle's handling and stability. Through changing the vehicle's structure parameters, the handling and stability of the driver-vehicle close-loop model are jointly optimized.3. When the driving condition changing, the thesis studies the changing trends of the combinatory evaluation index and the vehicle's structure parameters.4. Based on the front combinatory evaluation index, the property relation of the front-wheel and the rear-wheel by the optimized method is studied in this paper.The simulation researches show that optimizing the combinatory evaluation index of handling and stability can improve the vehicle handling and stability. Further more, this method also can enhance the vehicle's security. Based on the front combinatory evaluation index of handling and stability, the paper studies the property relation of the front-wheel and the rear-wheel by the optimized method. The research result shows that the new strategy can improve the handling and stability. The new strategy also can provide a research direction of the 4WS steering system's design.