Design And Control Research Of Electro-Hydraulic Brake-by-wire System

The electro-hydraulic brake-by-wire(EHB)system promotes the development of active braking for new energy vehicles or self-driving vehicles,which is believed to generate stable braking performance and reduce unnecessary energy consumption.To improve the active braking performance of the EHB system,the structural design,dynamic characteristics,and dynamics model of the EHB system are researched in this paper.A pressure tracking sliding mode control approach is presented,which is verified by simulation and bench experiments.Firstly,the structure,dynamic characteristics,and dynamics model of the EHB system are analyzed.A novel EHB system is designed,and the key parameters of the braking booster mechanism are selected,which achieves the development of the prototype.The relationship between the brake pressure and the motor position is established by openloop experimental testing,and it is found that the position and speed of the motor have a significant effect on the establishment of the brake pressure.According to the power signal transmission of the EHB system,the electro-mechanical system model,the hydraulic model,and the signal wheel model are established,and the correctness of the established models is verified.Based on the dynamics model of the EHB system,a pressure tracking sliding mode control approach is designed,and the stability analysis and the robustness analysis of the approach are analyzed.At the same time,to verify the ground-braking performance of the EHB system,the ABS controller is designed.A pressure tracking sliding mode control approach and ABS controller are modeled by MATLAB/Simulink software,and a whole vehicle model is built by the Trucksim software.Combining the controller model and the whole vehicle model,a co-simulation platform of MATLAB/Simulink-Trucksim is established.The feasibility of the EHB system model and a pressure tracking sliding mode control approach is validated by MATLAB/Simulink software,and the effectiveness of the ABS controller is verified by the co-simulation platform.On the basis of simulation verification,the test platform of the EHB system is established and the experimental verification is completed.A pressure tracking sliding mode control approach is embedded into the brake control unit(BCU),and tests are carried out under three different brake conditions,including sinusoidal braking pressure signal,slope braking pressure signal,and step braking pressure signal.The experimental results show that the proposed pressure tracking sliding control approach in this paper can effectively control the brake pressure of the EHB system and has a good active braking performance.