Automatic Emergency Braking Strategy Based on Dynamic Collision Time Considering Road Adhesion Conditions

Conventional autonomous emergency braking (AEB) strategies based on time-to-collision (TTC) often fail to account for the influence of varying road adhesion conditions on braking performance, potentially compromising safety in low-friction environments. To address this issue, a dynamic TTC threshold model that incorporates road adhesion characteristics is proposed, along with a fuzzy PID-based AEB control strategy. A rule-based adjustment mechanism is established to associate TTC thresholds with representative road friction levels, enabling the AEB system to adapt to different surface conditions. The fuzzy PID controller enables refined control of braking deceleration, ensuring both stability and comfort during emergency maneuvers. Extensive simulations are performed under various initial speeds and road conditions to determine the optimal TTC thresholds. Results show that, compared with traditional TTC-based AEB strategies, the proposed approach improves collision avoidance success rate by 14.2% under low-adhesion scenarios, demonstrating superior overall performance and environmental adaptability.