Functional modification based on insufficiency identification and fault-tolerant control for cooperative adaptive cruise control systems

Cooperative adaptive cruise control (CACC) has demonstrated significant potential to reduce driver fatigue and enhance driving safety and comfort. However, the Safety of the Intended Functionality (SOTIF) of CACC, particularly with respect to communication delays and intermittent interruptions, remains insufficiently addressed. These issues can result in inaccurate information reception within the vehicle platoon, thereby compromising both the safety and stability of the platoon. To address these challenges, this paper analyzes the functional insufficiencies of the CACC communication system and proposes a method for identifying functional insufficiencies, along with a switching fault-tolerant control approach to ensure the safety and stability of CACC systems under communication delays and interruptions. First, the functional insufficiencies are analyzed, and a functional insufficiency identification method based on data buffering is introduced. This method leverages vehicle platooning characteristics and uses timestamps from buffered vehicle state information to detect communication delays and interruptions. Second, a fault-tolerant switching control method based on model prediction is developed. This approach utilizes a constant acceleration model to predict vehicle motion states, correcting the impact of communication delays, while switching among multiple fault-tolerant controllers to address interruptions. Finally, a series of comparative experiments were conducted on both simulation and Hardware-in-the-Loop (HIL) platform. The results demonstrate that the proposed methods effectively ensure the SOTIF of the CACC system under various communication delays and intermittent interruptions.