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.
