Research On Vehicle Stability Control Based On Dual-source Redundant Braking System

The popularization of automobiles has greatly improved people’s travel conditions,but the frequent occurrence of traffic accidents has brought huge economic losses and even endangered personal safety.Vehicle instability during driving is an important cause of traffic accidents.At this stage,the development of smart cars has improved the stability of cars to a certain extent.However,most of the existing vehicle stability control systems are based on traditional electronic hydraulic braking systems,which are difficult to meet the requirements of smart cars for the reliability and real-time performance of the braking system.The brake-by-wire system of a smart car should be able to maintain a certain level of performance even when some components fail.At the same time,it also requires the system to have a faster pressurization speed and a higher pressure regulation accuracy.In response to the above requirements,this paper designs a dual-source redundant braking system(DSRB)that meets the needs of smart cars,and conducts research on vehicle stability control based on this system.First,by analyzing the special requirements of smart cars for the braking system,a dual-source redundant braking system is designed,and its three working modes are introduced respectively.The DSRB system model was established by using AMESim software,and based on the model,the DSRB system was simulated under three working conditions: normal operation,partial failure and complete failure.The results show that the DSRB system can quickly adjust the wheel cylinder pressure,and the speed of increasing pressure of the EHB system is increased by 0.33 s.At the same time,in the event of partial or complete failure of the DSRB system,the system can still increase,hold and decrease pressure quickly.Even under complete failure conditions,the speed of increasing pressure of the DSRB system is 0.08 s faster than that of the EHB system.This provides effective support for the following research on wheel cylinder pressure control based on the DSRB system.Secondly,the wheel cylinder pressure control algorithm based on the DSRB system is introduced,and the wheel cylinder pressure PID controller is designed.The physical simulation model and control model of the DSRB system were built in AMESim and Simulink,and based on the model,co-simulations were carried out under three conditions of normal operation,partial failure and complete failure.The results show that under ESC conditions,wheel cylinder pressure control algorithm based on the PID control can quickly and accurately control the wheel cylinder pressure,and the response time is 0.3s regardless of the assist mechanism.In addition,in the event of partial or even complete failure of the DSRB system,the system can still increase,hold and decrease pressure quickly,and the speed drops to 0.7s only during the secondary pressurization under the conditions of complete system failure.This provides a strong guarantee for good control of vehicle stability below.Then,starting from the cause of instability,the vehicle stability state judgment algorithm is designed,the direct yaw moment is selected as the indirect control parameter,and a two-dimensional fuzzy controller for vehicle stability is designed.The corresponding wheels are selected for control,and the additional yaw moment is applied to the controlled wheels in the form of additional braking force,thereby correcting the unstable state of the vehicle during driving.This provides a theoretical basis for vehicle stability control simulation.Finally,a dual-source redundant braking system simulation model was established based on AMESim,Simulink and CarSim.The vehicle stability control was simulated under two extreme conditions,namely sharp turning and obstacle avoidance based on emergency steering.The analysis of the results shows that the dual-source redundant braking system designed has a good control effect on vehicle stability.