Research On Collision Avoidance Strategy Of Automatic Emergency Braking System

In recent years,China's economic strength has continuously improved,resident motor vehicle ownership is on the rise.While the number of motor vehicle ownership and drivers are increasing,the number of road traffic accidents are also rising.Reducing road traffic accidents,reducing the severity of accidents,and improving the safety performance of vehicles are the requirements of drivers.It further drives Automobile manufacturer to build safer vehicles.Automatic emergency braking?AEB?is an important vehicle active safety technology.Research shows that it can avoid 27%of traffic accidents and it can reduce the damage of people and vehicles in the event of an accident.Therefore,this paper researches the collision avoidance strategy of the automatic emergency braking system.In this paper,the emergency braking behavior characteristics of the driver under typical dangerous conditions are obtained through questionnaires and UAV aerial video.Based on the results of data analysis,a risk estimation algorithm and collision avoidance strategy are established.Finally,the effectiveness of the collision avoidance strategy is verified by PreScan simulation modeling.First,we surveyed the driver's basic information,safe driving information,and the factors affecting the driver's emergency braking.The questionnaire quantifies the driver's perception of using the automatic emergency braking system by the Likert scale and uses factor analysis to analyze it.Through the factor analysis,the driver's perception of using the automatic emergency braking system is summarized into eight main factors.The result shows that most drivers believe the automatic emergency braking system plays an important role in safe driving.Moreover,the driver tends to use automatic emergency braking system to avoid collision in the case of bad weather such as rain and snow,and poor road lighting conditions at night or when crossing an intersection with complicated driving conditions,and the use of automatic emergency braking system can alleviate driving fatigue to a certain extent.Secondly,the vehicle's motion characteristics at 10 road openings are obtained by UAV aerial video.The video processing software Tracker is used to process data processing of the aerial video to obtain vehicle speed,the average braking deceleration of the emergency braking moment,and time-to-collision?TTC?.A total of 349 cases of general hazard and heavy dangerous conditions were screened from aerial video.Then analysis of such cases,the two most important parameters affecting the driver's emergency braking collision avoidance effect are the average braking deceleration of the emergency braking moment and TTC.Then build the risk estimation algorithms for different TTC conditions:When the TTC less than 5s,a risk estimation algorithm based on the inverse of TTC is used,the TTC^-1-threshold value of different hazard levels is set to correct the driver's steering tendency caused by the speed increase;For car-following conditions with TTC greater than 5s,risk estimation algorithm based on request deceleration is used for hazard identification.Both risk estimation algorithms classify hazard conditions into four levels:safety,general hazard,and larger hazard,heavy dangerous.Different hazard levels are supplemented by corresponding collision avoidance strategies.A collision avoidance strategy with two levels of warning is established,including prompt warning and collision warning.As the level of danger increases,the vehicle assists the driver in braking to avoid collisions.Finally,the article follows the automatic emergency brake system effectiveness test method recommended by Allegemeiner Deutsche Automobil-Club?ADAC?.Using PreScan combined with Matlab/Simulink to verify the effectiveness of the risk estimation algorithm and collision avoidance strategy established above are divided into three conditions:front car uniform speed,uniform deceleration and static state.The simulation results show that the risk estimation algorithm and collision avoidance strategy of the above research can effectively avoid the occurrence of collision accidents or mitigate the seriousness of collision accidents.