Study On The Control Method Of Integrated Electro-Hydraulic Braking System And The Strategy Of AEB Collision Avoidance

With the development of new energy vehicles and intelligent networked vehicles,it has become an inevitable trend to develop integrated electro-hydraulic braking system with high integration degree,good efficiency and stability.The integrated electro-hydraulic braking system not only meets the basic braking control requirements,but also helps the vehicle realize the function of automatic emergency braking system(AEB),so as to alleviate the life safety and property loss caused by traffic accidents such as rear-end collision.This paper proposes an integrated electro-hydraulic brake system,and its structure and working principle are introduced.At the same time,the mathematical models of main components are built.The mathematical models including the power of motor,the transmission mechanism,the servo master cylinder,the brake line,the solenoid valve and the wheel cylinder.Based on Matlab/Simulink and AMESim simulation software,the simulation model of each main component was established respectively.The interface module of Simulink of the two simulation software was built.The co-simulation model of integrated electro-hydraulic braking system is established,which lays a foundation for the control method and simulation test of integrated electro-hydraulic braking system.This paper researches the control method of integrated electro-hydraulic braking system,including servo master cylinder pressure control method and ABS control method.A three closed-loop control method based on pressure-position of the double variable switching is designed for servo master cylinder pressure control,in which the outermost loop is pressure-position bivariate switch control loop,the middle loop is speed control loop,and the innermost loop is current control loop.An adaptive logic threshold ABS control method based on road identification is proposed for ABS control.Based on the co-simulation model of the integrated electro-hydraulic braking system and the servo master cylinder pressure control method,the simulation analysis of the tracking servo master cylinder pressure is carried out.A co-simulation platform composed of AMESim,Simulink and CarSim software was used to conduct simulation analysis under ABS braking conditions.This paper also researches AEB collision avoidance control strategy and introduces AEB control architecture based on integrated electro-hydraulic braking system.According to the existing collision avoidance strategies,the characteristics of braking safety and driving comfort are analyzed.The critical safe distance calculation method based on vehicle and road condition parameters and the safe distance calculation method based on driver braking behavior characteristics are established respectively.The braking safety and driving comfort in collision avoidance strategy were quantified,and the comprehensive performance optimization model of AEB collision avoidance strategy was established.This paper introduces the composition of Hardware In Loop(HIL)and working process and set up the HIL test bench based on the ECU of integrated electro-hydraulic brake system.The servo master cylinder pressure control method of integrated electro-hydraulic brake system and its accuracy of the simulation test have been validated in HIL test bench.At the same time,ABS control method of integrated electro-hydraulic brake system and its accuracy of the simulation test also have been validated in HIL test bench.Finally,the C-NCAP test was carried out in the HIL environment and the accuracy of the established AEB collision avoidance strategy was verified.