Vehicle Stability Research During Curved Brake Based On Abs

Brake stability is one of key and important criterion for vehicle brake quality. Curved brake,different from straight line brake, will cause vehicle oversteer or understeer even spin for the reason of load transferred. Based on ABS, this paper focused on the vehicle stability when curved brake.First, by introduction of tyre coordinate,tyre model and brake actuator model, an eight degrees of freedom of vehicle dynamic model has been established. These eight degrees were longitudinal motion, lateral motion, yaw movement, roll movement and turn movement of four wheels. Meanwhile this paper analyzed the calculation of wheel lateral deviation angel and load transfer.Second, the eight degrees of freedom of vehicle dynamic model has been simulated in this paper by using Matlab/Simulink. Then the reason of vehicle unstable when curved brake was analyzed and the way to improve the stability has been told which was differential brake by changing front and rear wheel slip.Third, a function for optimization which is under consideration of both brake efficiency and lateral stability has been built up, then by using PSO the slips of front and rear wheel were optimized.Then, the disadvantage of traditional ABS based on threshold is analyzed. A new control model, fuzzy logic control, for ABS is designed in Matlab Fuzzy Logic Controller and the controller is simulated in Matlab. The slip and the changing ratio of slip are the principle for designing the new ABS controller. The simulated results prove the efficiency of the new ABS controller.At last, the eight degrees of freedom vehicle dynamic model and the ABS fuzzy logic controller is combined together for simulation. Two working conditions, high mue road and low mue road, are simulated with certain inputs. Also, the simulated results proved the efficiency of the new ABS controller in cured brake and the simulated results also proved the expected slip that optimized before are right.