Research On Key Technologies Of Electric Power Assisted Braking System For New Energy Vehicles

New energy,unmanned driving and energy saving are the future direction of automobile development,which puts forward higher requirements and challenges for automobile braking system.Electric power assisted braking system(EHB)emerges as The Times require,because has the volume small,the weight is light,the response speed is quick,the braking effect is good,the wire control,the intelligence and so on the advantage,becomes the current automobile safety braking technology domain research hotspot.Based on the analysis of the research on electric power braking system at home and abroad,this paper studies the hardware and software design of the controller in the electric power braking system,basic power,active braking and the key technologies such as keeping the pedal feeling with regenerative braking.The main research contents are as follows.(1)By determining the implementation plan of the electric power braking system,the functional definition of the electric power braking system is proposed,and the structural design of the electric power braking system is completed.Combining with the structure of the braking system,the dynamic modeling of the key components is completed.According to the specific requirements,the construction of the comprehensive performance test bed for braking is completed,which provides the theoretical support and test platform for the research on the braking control strategy of the electric power braking system.(2)The basic power of EHB system,driver’s braking intention recognition,target displacement design on the basis of detailed analysis,put forward a series of three closed loop based on displacement,speed,current braking control strategy,complete the alldigital fuzzy follow precise displacement control,completely conform to the new requirements of brake systems on the future car.Realize the basic power-assisted braking function of electric power-assisted braking system.Including three points: basic power,adjustable pedal feeling,Failure of backup function.The EHB system tests the "inputoutput" characteristic curve of the braking force,the feeling of the brake pedal,the reaction release time,the braking distance and other core assessment elements.(3)Based on on-board monocular vision and 77 GHZ millimeter wave radar speed,relative distance,relative velocity parameters such as acquisition,estimating of the safety distance model through data processing,get into the active braking condition,to establish automobile velocity,pressure,current tandem three closed loop control,complete the precision of vehicle deceleration follow,finally realizes the active braking control.By analyzing the principle of regenerative braking and the influence on the pedal sensation of EHB system,an algorithm to keep the pedal sensation is proposed to ensure the safety and comfort of the vehicle.Finally,the feasibility is verified by experiments.(4)The EHB system designed in this paper was loaded onto the real vehicle test platform for road tests under various test conditions such as braking intention and initial braking speed,and the braking performance of the EHB system,Bosch iBooster system and traditional vacuum booster braking system was compared and analyzed.The test results show that the overall braking performance of the EHB system is better than that of the traditional vacuum booster braking system and even better than that of Bosch iBooster.