Robust control for connected automated vehicle platoon with multiple-predecessor following topology considering communication loss

The paper presents a robust control method for effectively managing uncertainties and communication loss in a connected automated vehicle (CAV) platoon under the multiple-predecessor following (MPF) topology. The proposed approach incorporates uncertainties in vehicle dynamics, such as vehicle parameters and environmental resistances, into the closed-loop platoon system to enhance the robustness of the platoon controller. The impacts of communication loss are analyzed specifically for the MPF topology, considering potential disruptions in information flow among different numbers and locations of predecessors in a CAV platoon. A novel formulation of desired spacing, suitable for CAV platoon with the MPF topology under communication loss, is then developed based on the constant time headway (CTH) policy. Furthermore, the paper derives and proves the sufficient and necessary conditions for the local stability of the proposed robust platoon controller using Kharitonov's theorem. The sufficient conditions for string stability are also discussed through frequency-domain analysis and combined with the Lyapunov function to determine the relationship between average dwell time and maximum allowable delay, ensuring platoon string stability under switching communication topology. These conditions establish the stability region for the robust controller of a CAV platoon with varying locations and numbers of unconnected predecessors. Simulation experiments are conducted to demonstrate that the stability region of the controller diminishes as the number of unconnected predecessors increases, with the greatest impact observed when the communication with the nearest connected predecessor is lost. Additionally, the control performance is affected by uncertain dynamics and the range of time headway, resulting in a significant reduction in the stability region. The findings highlight the importance of fine-tuning control parameters within the stability region guided by the derived stability conditions to ensure both local and string stability of CAV platoons.