Research On Vehicle Automatic Emergency Braking Method Based On PreScan

In recent years,China’s car ownership has shown an overall upward trend,which has also indirectly caused the continuous growth of the number of road traffic accidents,so that people’s lives and property have suffered huge losses.As the automatic emergency braking system(AEB,Autonomous Emergency Braking)is an important part of the vehicle active safety technology,it can be used as an important means to reduce the incidence of traffic accidents,so it is important to study the AEB control strategy.Through the vehicle dynamics estimation method and vehicle collision warning control strategy,complete the design of the overall automatic emergency braking system,build Pre Scan,Car Sim and Matlab / Simulink joint simulation platform,applied the proposed control strategy in the implementation scheme to verify its rationality and effectiveness.The following research are mainly conducted:First,the overall structure of the vehicle AEB system is constructed in combination with the vehicle state estimation methods.The control requirements,functions and working principle of the automatic emergency braking system are analyzed,and the main technologies of the system are summarized.Secondly,establish the vehicle state estimation module in the system design scheme,the internal model includes tire model and vehicle dynamics model,based on the square root no trace Kalman filter with tire model and vehicle dynamics model to estimate the vehicle state,obtain high accuracy speed of vehicle state information and send it as input to the collision warning control module in the overall system.Simulations show that the maximum error of transverse longitudinal speed is less than0.03 m/s.Then,the basic model of collision warning control module in the system design is established.Analyze the safety time model,and build the TTC(Time To Collision)and TTA(Time To To Avoidance)models,to determine whether the vehicle is in a state of emergency.Using the hierarchical control method,the upper layer controller with the anti-collision early warning and control strategy as the main body is established,and the output meets the expected deceleration under the current driving conditions.The lower controller is constructed based on the reverse model of the vehicle dynamics.The lower controller transforms the corresponding throttle opening or brake pressure input to the vehicle model according to the deceleration value planned by the upper controller to complete the longitudinal control of the vehicle.Finally,build a joint simulation platform of Pre Scan,Car Sim and Matlab /Simulink,refer to the typical test scenarios of E-NCAP(Euro-New Car Assessment Program)and C-NCAP(China-New Car Assessment Program),and verify the effectiveness of the designed automatic emergency brake control system through simulation experiments.The simulation results show that the estimation algorithm can accurately estimate the vehicle status.The proposed vehicle collision avoidance warning control strategy can adjust the system according to the vehicle and the movement state of the vehicle before the target,which can meet the requirements of AEB system design and application.