| In this paper the limitation of 4WS(Four Wheel Steering)under extreme conditions is considered,and 4WS and ESP(Electronic Stability Program)coordinate control to improve the 4WS vehicle’s stability has been proposed.Because the road condition has a great influence on the working effect of the 4WS and ESP systems,the extended Kalman filter method is used to estimate the road surface adhesion coefficient,and the effectiveness of the method is verified by MATLAB programming.Based on different road surface adhesion coefficients,the coordinated control strategy of 4WS and ESP system was designed.The fuzzy coordination controller was designed.The simulation was carried out by Carsim and Simulink,the simulation results show coordinated stability control of automobile 4WS and ESP System greatly improve the steering stability of the car compared with the single system.(1)Firstly,the stability control parameters have been determined,and the vehicle dynamics model and reference model have been established,besides,the actual model is compared with the reference model through simulation,verifying the accuracy and practicability of the reference model.(2)Through a certain fuzzy control strategy,the fuzzy controllers of automobile 4WS and automotive ESP system are designed separately,and simulation analysis is carried out to verify the effectiveness of fuzzy control.Furthermore,it is verified that,to some extent,the separate automobile 4WS system and the separate ESP system can improve the steering stability of the vehicle.(3)Based on the analysis of the limitations of the 4WS system of the automobile,the influence of different road surface adhesion coefficients on the 4WS system is considered.In this paper,the extended Kalman filter algorithm is used to estimate the road surface adhesion coefficient,and the real-time estimation of the road surface adhesion coefficient is carried out by MATLAB/Simulink and CARSIM co-simulation,and the feasibility of the algorithm is verified,Laying the foundation for collaborative control of 4WS with ESP systems.(4)The cooperative control model of 4WS system and ESP system is built in MATLAB/Simulink,and the simulation is compared with the individual control.The results show the effectiveness of collaborative control.And then,the influence of road surface adhesion coefficient on the 4WS system of the automobile is analyzed,and the road surface adhesion coefficient is introduced to optimize the coordinated control of the vehicle 4WS with ESP system.The simulation results show that the optimization strategy can effectively improve the steering stability of the vehicle.Based on the estimation of road surface adhesion coefficient,this paper studies the cooperative control of automobile 4WS and ESP system.Compared with individual 4WS and ESP system,this control strategy greatly improves the steering stability of the vehicle,and there is great reference value and research significance about the strategy. |
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