  Vehicle-to-vehicle communication enables autonomous platoons to boost traffic
efficiency and safety, while ensuring string stability with a constant spacing
policy. However, communication-based controllers are susceptible to a range of
cyber-attacks. In this paper, we propose a distributed attack mitigation
defense framework with a dual-mode control system reconfiguration scheme to
prevent a compromised platoon member from causing collisions via message
falsification attacks. In particular, we model it as a switched system
consisting of a communication-based cooperative controller and a sensor-based
local controller and derive conditions to achieve global uniform exponential
stability (GUES) as well as string stability in the sense of platoon operation.
The switching decision comes from game-theoretic analysis of the attacker and
the defender's interactions. In this framework, the attacker acts as a leader
that chooses whether to engage in malicious activities and the defender decides
which control system to deploy with the help of an anomaly detector. Imperfect
detection reports associate the game with imperfect information. A dedicated
state constraint further enhances safety against bounded but aggressive message
modifications in which a bounded solution may still violate practical
constraint e.g. vehicles nearly crashing. Our formulation uniquely combines
switched systems with security games to strategically improve the safety of
such autonomous vehicle systems.
