Simulation Analysis of Automatic Emergency Braking System under Constant Steer Conditions

Automatic emergency braking (AEB) systems improve the active safety of vehicles. Previous studies mostly focused on the performance of AEB under straight line motion, and rarely involved steer conditions. However, for a vehicle traveling on a curved path, the operation of the AEB system may cause the vehicle to move laterally out of the lane. Modeling of such motion can be done with vehicle dynamics simulation. In this article, the AEB performance of a vehicle under constant steer conditions is simulated and analyzed. A unified dynamics model of 18 degrees of freedom (DOF) vehicle chassis including longitudinal, lateral, and vertical motions is introduced. According to three different test scenarios in Euro NCAP, the emergency braking responses of point mass model and 18 DOF model on a straight line are simulated and compared based on time-to-collision (TTC) control algorithm. The simulation results of the two models above, including vehicle spacing, speed, deceleration, and TTC, are basically consistent. Similarly, according to the scenarios above, the emergency braking responses of the 18 DOF model under constant steer are simulated by MATLAB/Simulink. It is found that although the AEB system can effectively prevent collision with the lead vehicle, but make the lateral displacement of the AEB-equipped vehicle increase significantly, which may lead to other risks, such as collision with the road edge.