A Safety Margin-Based Automatic Emergency Braking Model

The Automatic Emergency Braking (AEB) system is capable of assessing driving risks, alerting the driver to potential collision hazards, and, in the absence of driver response to the collision risk, autonomously activating braking to mitigate the occurrence of collision accidents. Most existing Automatic Emergency Braking (AEB) systems rely on Time to Collision (TTC) for risk assessment and decision-making. However, TTC fails to account for the impact of absolute velocity on driving safety when assessing risk, leading to inaccurate risk descriptions, particularly in high-speed scenarios with minor speed differences. The Safety Margin (SM) takes into account key factors affecting driving risk, such as relative velocity and distance, and is capable of accurately quantifying driving risks. Based on the SM, this study proposes a full-speed range single-threshold Automatic Emergency Braking (AEB) model. The model comprises two components: traffic environment risk quantification and road surface friction coefficient estimation. It is applicable to automatic emergency braking tasks under varying speeds and road surface conditions. Simulation experiments were conducted by constructing three typical scenarios: stationary lead vehicle, slow-moving lead vehicle, and braking lead vehicle, to determine the braking threshold as 0.2. The safety performance of the proposed safety margin-based AEB model is evaluated by comparing it with the traditional TTC-based AEB model across the specified scenarios. The results demonstrate that the safety margin-based AEB model proposed in this study achieves 100% safe braking in all scenarios, successfully performing emergency braking and outperforming the TTC-based AEB model.