Research And Assessment On The Control Strategy Of Autonomous Emergency Braking System In Complex Situation

With the continuous development of Advanced Driver Assistant technology,people are paying more attention to automobile active safety system.As an important part of automobile active safety system,Autonomous Emergency Braking system shoulders an important responsibility in driver's driving safety.In the driver's driving process,there are often multiple target vehicles in the surrounding traffic environment.Due to the difference in the movement state of the surrounding target vehicles,how Autonomous Emergency Braking system avoids or mitigates collision in complex traffic environment is the core issue of its control strategy.This article relies on the research results and the project resources of the project team to propose an autonomous emergency braking control strategy in the complex situation,hoping to inspire the research in the same field.In order to ensure driving safety,the driver will first determine the vehicle that poses the greatest threat to the safety of the vehicle in a multi-target vehicle traffic environment,and then determine whether emergency braking is required.Simulating the driver's decision process,this paper divides the autonomous emergency brake control strategy into two modules:the first module is a scene analysis module.First,four different scene types are defined according to the relative motion relationship between the target vehicle and the host vehicle.Then the scene matching of the target vehicle is performed according to the vehicle state of the two vehicles at the current moment,and finally the same is passed firstly.Scene-type target vehicles are screened,and second-round screening is performed on target vehicles of different types of scenes to ultimately determine the most dangerous target.The second module is a dynamics control module.The main purpose is to evaluate whether to perform step braking and determine the corresponding braking strength based on the most dangerous target and the status information of the vehicle.Based on the relative motion state of the two vehicles,the TTC value is calculated using the second-order TTC formula and compared with the set threshold.If the threshold condition is satisfied,the safe distance model will work,otherwise no emergency braking is performed.A safety distance prediction model based on the ESC deceleration response characteristic is established in this paper.The model will estimate the braking start time point,the desired deceleration level,and the desired deceleration step change time point in real time.Because the safety distance prediction model adopts the control strategy of the staged braking,the switching time point control for switching the desired deceleration from a one-stage braking request to a two-stage braking request can eliminate the actual process during the preceding one-stage braking.The error between the deceleration and the desired deceleration solves the problem that the actual workshop minimum distance and the set safety distance error fluctuate greatly.In order to verify the rationality and effectiveness of the proposed control strategy,simulation experiments and real vehicle tests were conducted in this paper.The experimental results show that in the multi-objective vehicle traffic environment,the most dangerous target decided by the scene analysis module is consistent with the driver's expected result,and the dynamic control module can well relieve or avoid the collision under the conditions of CCRs,CCRm,CCRb and other conditions,to ensure the safety of the vehicle's driving.At the same time,the paper evaluates the simulation results and the actual vehicle test results.According to the C-NCAP test program and the scoring standards of the AEB function,it is concluded that the braking effect of the control strategy can achieve a higher score rate.