Cooperative Trajectory Optimization Strategy for Different Initial Train Conditions under Virtual Coupling

Abstract

Virtual coupling (VC) technology has been introduced in railway systems to enhance operational capacity. One of the key challenges in VC is ensuring a safe and effective train control strategy. For VC convoy operation control, while the existing literature mainly utilizes a distributed control architecture that focuses on the performance of individual trains, limited research focuses on optimizing the control trajectories for the entire convoy. To address this gap, this paper aims to plan a cooperative train trajectory for a VC convoy to improve the overall performance with respect to safety, punctuality, energy efficiency, and so forth. A hierarchical hybrid architecture is proposed for strategy planning and control of a VC convoy, considering the overall benefits of the convoy based on distributed control. Different initial conditions and the transition process of train states at junctions are investigated. A multi-objective nonlinear integer programming model is developed to optimize cooperative train trajectories during the coupling process by constructing a discrete speed–time grid network via the state lattices method. Simulation results demonstrate that the proposed method consistently meets the real-time safe separation requirements, showing adaptability to various combinations of initial train conditions and train operation plans. Compared with the two existing methods, the proposed method limits the deviation between the actual and the target operation times within 0.4 s, while reducing traction energy consumption by 2–4%, respectively. The proposed strategy advances the state of the art in VC train convoy control and shows promising potential to be applied to a real-world operational environment.