Research On Electro-Hydraulic-Brake System Suitable For Intelligent Driving Vehicles

Electro-Hydraulic-Brake system(Electro-Hydraulic-Brake,EHB),as a product of the transition from traditional hydraulic brake system to brake-by-wire(BBW),retains the well-developed hydraulic pipeline of hydraulic brake system,there are few changes to the vehicle structure and at the same time it has the advantages of fast response of the brake-by-wire system,small size,and low energy consumption.Intelligent driving vehicles emphasize system integration,wire control,and precision.The use of the EHB system is more conducive to the integrated control of the intelligent driving vehicle.Therefore,research on the structure of the new EHB system and related control strategies based on intelligent driving vehicles is of great significance to promote the development of intelligent driving vehicles.The research content of this paper mainly includes the following aspects:1.Design a parallel EHB system for intelligent driving vehicles.The system is divided into a boost subsystem and a backup brake subsystem,which are connected in parallel in the brake circuit through a one-way shuttle valve,and analyze the working principles of the two subsystems.Complete the design of key components of the new EHB system based on the relevant parameters of the vehicle.2.Establish the mechanical subsystem model and hydraulic subsystem model of the parallel EHB system,build a system test bench for the time-varying and nonlinear characteristics of the parallel EHB system,and compare the PV characteristics,exhaust characteristics,and exhaust characteristics of the parallel EHB system.Experiment and analyze the temperature rise characteristics of electronic components to determine several factors that affect the system’s pressure build-up,and further optimize the system.3.Carry out dynamic analysis of the vehicle’s straight braking conditions,establish a vehicle dynamics model,and propose a braking force distribution control strategy for the vehicle’s straight braking.According to the braking intention,the total braking force of the vehicle is obtained,combined with the sprung mass and the un-sprung mass distribution of the vehicle,the load transfer amount of the front and rear axles when the vehicle is braked is calculated,and the front and rear axles are carried out according to the dynamic changes of the load of each axle.The braking force distribution of the wheels is finally verified by simulation to verify the effectiveness of the relevant control strategies.4.Carry out dynamic analysis on the braking conditions of the vehicle,determine the control variables according to the factors that affect the vehicle instability,and propose the braking force distribution control strategy when the vehicle is braking in the curve.The braking force of the front and rear axles during straight braking is used as the reference braking force,and the additional braking torque controller is designed based on the control algorithm fused with the radial basis neural network and PID,based on the relationship between the additional braking torque and the yaw moment of the vehicle body The braking force distribution strategy is formulated,and the reference braking torque and the additional braking torque of each wheel are applied to each wheel according to the relevant rules.Finally,the simulation verifies that the designed controller is more superior than the pure PID control.