Research On Response Characteristics And Control Of Integrated Brake-by-Wire System For A Sedan

Whether it is in order to improve the driving safety and vehicle integration,or to meet the demand of intelligent automobiles and new energy vehicles,integrated brake-by-wire system is the important direction of research and development.At present,integrated brake-by-wire system is mainly electronic hydraulic braking system,which has several main characteristics such as building up pressure actively,controlling pressure accurately,decoupling system fully,and so on.At the same time,integrated brake-by-wire system needs to have the functions of conventional braking,ABS control,TCS control,ESC control,ACC control,AEB control and regenerative braking.The response characteristics and the controller of integrated brake-by-wire system are the key to affect the characteristics of “building up pressure actively” and “controlling pressure accurately”,which is also the key to realize the corresponding functions.Based on the project of Ministry of Science and Technology,the paper has carried on the research of the response characteristics and control of integrated brake-by-wire system.And the paper has discussed the actuator modeling,response characteristic analysis,controller design,optimization,hardware-in-loop test and simulation verification.(1)Study on open loop response characteristics of integrated brake-by-wire system.Based on the components' structure principle and the dynamics equation,the corresponding simulation models are set up using MATLAB/Simulink software.And according to the principle of integrated brake-by-wire system to build the system's simulation model.Based on the simulation model,the influence of the structural parameters of the key components on the open loop response characteristics of the the system is studied,and the basis for the structure optimization of the system is provided.(2)Controller design and optimization of integrated brake-by-wire system.The actuator controllers include the linear valve controller,the normal open valve controller and the normal close valve controller.The linear valve controller has critical influence on the response characteristics of the system,the paper has used PID algorithm to design the liner valve controller,and used fuzzy algorithm to optimize the PID controller.But fuzzy PID controller doesn't have a better improvement on the response characteristics of the system.The overshoot is still too large which goes against the stability of the system and driving safety.So,on one hand,the paper uses the “optimal Latin hypercube ”experimental optimization method to optimize the actuator.On the other hand,the paper uses the particle swarm algorithm to optimize the liner valve controller.The system's response characteristics meet the performance requirements after optimization.(3)Simulation verification of integrated brake-by-wire system.Building the simulation platform of the vehicle models,ABS controller,TCS controller,ESC controller and integrated brake-by-wire system using Carsim software and MATLAB/Simulink software,and selecting typical working condition for simulation.(4)Hardware-in-loop verification of integrated brake-by-wire system.The paper tests the function of “building up pressure actively” and “controlling pressure accurately”,and compared with the simulation.The result shows that integrated brake-by-wire system can realize the function better.