Resilient virtual coupling control of automatic train convoys with intermittent communications

Railways around the world are facing ever-increasing demands from booming passenger and freight transportation. Constructing new railways is not always possible due to the high cost and the lack of space. Virtual coupling (VC), which enables multiple trains to run cooperatively and closely on the same track, stands out as a major technological enabler for improving the existing railway network capacity and operational flexibility. This, however, relies on a feasible longitudinal spacing controller for each train such that the entire virtually coupled train convoy can function smoothly, safely, and efficiently. The design of such a spacing controller is intrinsically challenging as the train-to-train (T2T) communications, the primary enabling component for VC, may be interrupted by malicious cyber attacks. This paper addresses a resilient VC control problem for multiple automatic trains subject to intermittent T2T communications. First, an intermittent data transmission paradigm is presented to account for the effects of attack-incurred sporadic T2T communications. Then, a resilient distributed longitudinal spacing control method is developed to preserve the desired stability of the resultant train control system, while simultaneously guaranteeing attack resilience as well as driving safety and comfort requirements for the train convoy. It is shown that the proposed method is also effective in empowering a better trade-off analysis between traffic efficiency and safety than some traditional methods. Finally, numerical case studies using data from a realistic urban rail transit line substantiate the efficacy of the proposed method.