Research On Active Safety Control System Of Electric Vehicle Chassis

At present,with the increase in the use of automobiles,while meeting people’s daily needs,safety during driving is also receiving more and more attention.The safety of the car is divided into active and passive safety,of which active safety is the most important.Anti-lock braking system ABS(Anti-Braking System)and electronic stability program ESP(Electronic Stability Program),as an important part of the vehicle chassis control system,are the key to the active safety of the car,and the coordinated control of the two has become an inevitable development trend in the research of the automobile braking system.The traditional control method is a simple superposition of ABS braking system and ESP system,so that there will be coupling interference between systems,which not only reduces the working effect of the system,but also affects the active safety performance of the vehicle.However,through the coordinated control of the ABS braking system and the ESP system,not only the work efficiency of the two systems can be improved,but also the active safety of the vehicle can be improved.Therefore,studying the coordinated control strategy of ABS braking system and ESP system of vehicle chassis is of great significance to improve the active safety of vehicles.This paper introduces the composition and working principle of ABS braking system and ESP system,builds a vehicle model of electric vehicles through Car Sim software,and sets the simulation working conditions of this article.In view of the traditional ABS fuzzy braking system,the fixed value of the best slip rate replaces the real-time optimal slip rate in vehicle operation,resulting in the problem of inaccurate control,and the ABS fuzzy control strategy is improved.In this paper,an independent four-channel ABS fuzzy control strategy based on pavement slip rate recognition is proposed,and the main method is to calculate the optimal slip rate under the current pavement through the pavement adhesion coefficient,and perform separate fuzzy control for each wheel when needed.The improved ABS control strategy is built by Simulink software and co-simulated with Car Sim vehicle model,and the results show that the improved ABS control strategy is superior to the traditional ABS fuzzy control strategy in terms of braking distance and braking time.After analyzing the ESP system,the fuzzy control strategy of ESP system is improved according to the different control effects of fuzzy control and fuzzy PI control strategy in different road environments.In this paper,a pavement type judgment module is added to determine the pavement type by the pavement adhesion coefficient,and the best fuzzy control strategy is selected.The improved fuzzy control strategy is to brake on one side wheel to improve the control effect of the ESP system.The improved ESP control strategy is built in Simulink software and co-simulated with the vehicle model in Car Sim,and the results show that the improved control strategy improves the vehicle yaw angle velocity and centroid declination angle.On the basis of the improved ABS braking system and ESP system,the coordinated control is carried out by the design of the coordinating controller,mainly judging by the yaw angle speed and slip rate,and determining the working state of the ABS braking system and the ESP system.Simulation tests are carried out under different road conditions,and the results show that the improved ABS braking system and ESP system are superior to the separate control of the two subsystems in terms of slip rate,yaw angle velocity and centroid declination under the coordinated control strategy.Therefore,the coordinated control of the two subsystems can greatly improve the active safety performance of the vehicle.