Research On Heavy Vehicle Air Pressure ABS Control System

With the rapid development of China's e-commerce and logistics,our demand for heavy-duty vehicles is growing.Due to the characteristics of large load mass,long body and high center of gravity,heavy-duty vehicles are prone to accidents such as rollovers,causing huge loss of life and huge economic losses.Therefore,improving the safety factor of heavy vehicles is a development trend.Anti-lock Braking System(ABS)is an important device to ensure the active safety of the car.It can prevent the wheels from “locking” when the car is braking,thus significantly improving the braking performance and shortening the braking distance.This article has conducted in-depth research on the Dongfeng commercial vehicle DFL1250A12.The specific content of this paper is as follows:Firstly,the basic composition,control principle and control process of air pressure ABS are introduced.The relationship between ground braking force,brake braking force and adhesion is analyzed by a single wheel model.Then the relationship between the slip rate and the adhesion coefficient of different road surfaces is analyzed.Then,the vehicle model based on TruckSim and the ABS controller model and pressure proportional distribution model based on Maltlab/Simulink are designed.The joint simulation model is built and the feasibility of the model is verified by ABS pressure dynamic response comprehensive test.Secondly,the logic threshold controller and the PID controller are designed separately.Combining the advantages and disadvantages of both,the logic threshold and PID integrated control are proposed.The integrated controller is controlled by the logic threshold as the outer loop to determine the boost,hold or decompression,and the PID control of the inner layer is based on the current The slip rate deviation calculates the most suitable rate of increase and decrease.It is verified by simulation experiments that it achieves a good control effect,the brake pressure changes more smoothly,and the wheel slip rate can be well maintained near the optimal slip ratio.Thirdly,the hardware circuit design of ABS controller with Infineon XC2365 A as the core is completed,including microprocessor,power supply circuit,crystal clock circuit,OCDS circuit,wheel speed signal processing circuit,solenoid valve drive circuit and optocoupler isolation.Circuit,CAN communication circuit and K-Line diagnostic circuit,and completed the controller PCB design.Finally,based on the hardware-in-the-loop Simulink test(HIL)bench developed by the Tsinghua University's State Key Laboratory of Automotive Safety and Energy,the test of high-adhesive pavement,low-attachment pavement,butt pavement,off-road pavement and ice surface linear braking is verified.It is verified that the logic threshold is added to the ABS controller and the PID integrated control can meet the expected braking requirements.