Stability issues for vehicle platooning in automated highway systems

This paper discusses notions and definitions pertinent to the stability of systems operating in platoon structures. This paper reviews some of the existing stability definitions (string stability), and discusses how the available platoon information and separation policies influences the stability results. It turns out that some of these notions and control policies do not suffice to ensure safety (collision avoidance) of the platoon. This is illustrated via simulation examples showing that there exists, in general, a non-empty set of initial condition that results in a colliding situation. This set is not necessarily small. In connection with this, we propose a new way to formulate the platooning problem aiming at solving some of these difficulties.