Research On Handing Stability Control Of Vehicle Based On Phase Plane Analysis

Under the increasingly serious energy crisis and environmental pollution,electric vehicles have become the inevitable choice for the development of the automobile industry.As an important part of the active safety,the handing stability control of electric vehicle has also become a key problem for people to study.Aiming at the problem of vehicle instability and difficult driving according to the driver's steering intention under the action of nonlinear tire force,the handling stability control of distributed drive electric vehicle is studied.First,the nonlinear seven DOF distributed drive electric vehicle model,including the motor model and the tire model,is built in the Matlab/Simulink software.The road friction coefficient and the side slip angle are estimated in the handling stability control of vehicle,which are important but difficult to directly obtain.And the simulation experiment shows that the design of this estimation method can meet the need in this paper.Secondly,aiming at the vehicle selected in this article,phase plane of yaw rate-side slip angle and side slip angle-side slip rate are designed according to the phase plane theory,and the boundary of the stable domain and the unstable domain in the phase plane is studied.Based on that,the boundary model is established,and the influence of vehicle speed,road friction coefficient and front wheel steering angle on the boundary model is analyzed.Thirdly,in the unstable domain,PID yaw moment control strategy is designed based on two phase planes,and the distribution coefficient of the two control strategies is optimized by fuzzy neural network control strategy;In the stable domain,the fuzzy control strategy is used to determine the yaw moment,so that the vehicle can follow the ideal state value under the stable state.The quadratic programming method is used to distribute the yaw moment to the four motors so as to output the optimal longitudinal force of each wheel and finally realize the control of handing stability.Finally,based on the simulation platform of distributed drive electric vehicle model and handling stability control strategy,the handing stability of the vehicle is simulated and analyzed by using three conditions: J-turn,sine hysteresis and amplitude increase sine.