Automatic Emergency Braking System On Control Strategy Of Intersection CAR

In recent years,with the increase in car ownership,the number of traffic accidents has also increased year by year.Automotive active safety technology is receiving more and more attention.Among them,the automatic emergency braking system(AEB)can effectively avoid the occurrence of collision accidents or reduce the damage of collision accidents.In China,the proportion of traffic accidents involving electric two-wheelers is quite large,mainly at accidents at intersections.Therefore,to develop a vehicle AEB system suitable for China's road traffic scenarios,full consideration must be given to the protection of electric two-wheeler riders.Based on 62 sedan-electric two-wheeler traffic accidents that occurred at intersections in Songjiang area,this article studies accident collision characteristics,vehicle dynamics models,safety distance models,hierarchical braking strategies,and scene fusion.The research contents are as follows:(1)By performing accident reconstruction on the selected 62 car-electric two-wheeler accidents,the motion parameters of the car and electric two-wheeler can be obtained 5s before each accident,including vehicle speed,acceleration,steering wheel angle,etc.Based on the detailed parameters obtained later,an accident information database is established.The dynamic response of the rider in a collision accident is also studied,and the impact of the collision speed,collision position,and collision angle on the rider's dynamic response is obtained.Provide data support for the subsequent collision avoidance strategy research and simulation verification of the AEB system.(2)The vehicle dynamics model is established in the simulation software based on the actual vehicle parameters,including the vehicle's lateral dynamics model and longitudinal dynamics model,as well as the engine model,transmission model,wheel model and brake model,and the control body stability is established.Controller model to improve the accuracy of the vehicle dynamics model in simulation.(3)The safety distance model is the basic part of the AEB system.This article uses binocular cameras and millimeter-wave radar to detect the target's relative distance,relative speed,and relative angle.The TTC model,the longitudinal safety distance model,and the horizontal direction are analyzed separately.Safety distance model.(4)Based on the safety distance model,the time index Tb is selected as the index of early warning and stepped braking.For electric two-wheelers whose goal is to cross the road laterally,this paper studies the control method combined with steering brake control,and performs steering brake control to avoid collision damage in the case of collisions that cannot be avoided.(5)Based on the typical test scenario of AEB in C-NCAP,62 accidents were divided into 4 types of scenarios,and the collision environment of 62 accidents was simulated and constructed by Pre Scan software,and cameras and radar sensors were established to combine the established vehicle power.Model,and conduct joint simulation verification of the designed AEB control strategy.Analysis and comparison of the original accident and the collision avoidance and vehicle motion parameter changes after adding the AEB control strategy verify the effectiveness of the AEB control strategy studied in this paper.The simulation verification results show that when the vehicle speed is below 65 km / h,the vehicle approaches the front stationary electric two-wheeled vehicle,the electric two-wheeled vehicle traveling at a constant speed,and the two-wheeled vehicle with a uniform braking speed are above 90%.In the scenario of a horizontal and uniform motion electric two-wheeler,the collision avoidance rate is 84.6%.After the AEB system is involved,the collision accident cannot be avoided,the collision angle changes,and the vehicle speed is also significantly reduced.