Optimization Of Automobile Vacuum Auxiliary Braking System And Analysis Of Auxiliary Braking Performance

With the rapid development of automotive technology,more and more people pay attention to the safety performance of the car.Especially the braking safety is more important.Good braking safety will determine the braking distance,braking stability and other factors,so can avoid traffic accidents.In order to have a better braking effect,the auxiliary brake is usually used to solve the problem.The current mature method of auxiliary brake are retarder,engine exhaust auxiliary braking device,engine retarder,eddy current retarder etc.In this thesis,a kind of automobile auxiliary mode is automobile vacuum assisted braking system.The working principle of the system is to use the principle of vacuum to provide additional braking force for the vehicle,so as to achieve the purpose of improving the braking performance of the vehicle.The main contents of this paper are as follows:The classification of auxiliary braking device and the working principle and working characteristics of all kinds of auxiliary braking device are introduced.The domestic and international development situation of the current auxiliary braking device are introduced.The composition and working principle of automobile vacuum auxiliary braking system are introduced.The function of each component of the vacuum assist brake system and the selection principle of each part are described.Three dimensional model of auxiliary braking system is builded.The feasibility of automobile vacuum auxiliary braking system is analyzed.The static performance of the the automobile auxiliary braking system is analyzed.The working strength of each structure is verified.Which ensure the structure of the auxiliary brake system can meet the working requirements.The driver’s braking intention can be divided into three categories: emergency braking,regulating braking and gentle braking.Collecting sampling data of brake operation by driving simulator,the driver’s braking intention identification model is builded by BP neural network.The BP neural network is trained and verified by sample data.The effect of auxiliary braking force of automobile auxiliary vacuum system is analyzed.Vehicle dynamics mathematical model with vehicle dynamics theory is builded.The simulation model of seven degrees of freedom vehicle is builded based on Matlab/Simulink software.The simulation results of the Carsim software are compared with the simulation results of the seven degree of freedom simulation model of the vehicle,which verifies the accuracy of the simulation model of the seven degree of freedom.The effect of automobile vacuum brake system on braking performance of automobile based on seven degree of freedom simulation model is simulate.