Research On Different Control Strategies Of Automotive Electronic Stability System

Automobiles are prone to instability when turning at high speeds on low adhesion coefficient roads or in emergency avoidance of obstacles.The automotive electronic stability control system can monitor the running state of the automobile in real time and apply control,which effectively guarantees the stability of automobile handling stability.This paper has practical value to study the different control strategies of automotive electronic stabilization system on low adhesion coefficient roads.The magic formula tire model was established,and the tire force during turning and braking was corrected.On the basis of the tire model,a seven-degree-of-freedom model of the whole vehicle was established,and a simplified linear two-degree-offreedom ideal model was established.The simulation model was build in MATLAB/Simulink,and the built vehicle model was verified.The influencing factors of vehicle stability and the direct yaw moment control strategy were analyzed,and the yaw rate and the side slip angle of the center of mass were selected as the control variables.The ideal values of the two control variables were calculated,and the vehicle instability was analyzed.The single-wheel brake control logic was designed in MATLAB/Stateflow,and the yaw moment distribution model was established in MATLAB/Simulink and built it on the vehicle model.Four controller models were established based on PID,fuzzy and sliding mode control strategies,and the built controllers all controlled the yaw rate and the side slip angle of the center of mass jointly.When designing the fuzzy sliding mode controller,the integral sliding mode controller was designed based on the equivalent control method.The center of mass slip angle was used to coordinate the weighting system to adjust the weight ratio of the variable deviation,and the fuzzy control rule was used to adjust the switching gain of the sliding mode controller.Two kinds of signals,step and sine,were respectively input on the road with low adhesion coefficient,and the vehicle models controlled by four different control strategies were simulated,and the effects of automobile ESC control under different control strategies were analyzed.The simulation results show that the PID controller,fuzzy controller,parameter self-tuning fuzzy PI controller and fuzzy sliding mode controller have good control ability when the automobile is turning at high speed or emergency avoiding obstacles on the road with low adhesion coefficient.The parameter self-tuning fuzzy PI Controller and the fuzzy sliding mode controller are more significant,and the fuzzy sliding mode control is the best.Under the step condition of fuzzy sliding mode control,the steadystate value of the yaw rate is only 0.005rad/s away from the ideal value,and the lateral slip angle of the center of mass almost coincides with the ideal value,only a difference of 0.003rad;under the sine condition,the yaw rate exceeds the ideal value.The difference between the overshoot value and the ideal value is only 0.04rad/s,and the slip angle of the center of mass is also only a difference of 0.008 rad.Therefore,fuzzy sliding mode control has faster response speed,better steady-state effect,more accurate tracking of the ideal value,can generate greater yaw moment,and can better control the stability of the car,which verify the correctness of the control model.