Collaborative scheduling of handling equipment in automated container terminals with limited AGV-mates considering energy consumption

Abstract

AGV-mates (automated guided vehicle, AGV) are a type of buffering equipment installed in the seaside area of the yard block, which can decouple AGV and yard crane operations. In recent years, an AGV charging function has been integrated in AGV-mates, providing AGVs with an alternative charging method besides battery recovery at the battery swapping station. This has resulted in time constraints and additional energy replenishment decisions in collaborative scheduling optimization, complicating the terminal equipment scheduling problem. Therefore, this paper investigates the collaborative scheduling problem of yard equipment in each operation stage of an automated container terminal, proposes charging-swapping mode for AGV energy replenishment, and develops a mixed integer programming model to minimize equipment no-load energy consumption and operational delay costs. In order to address the difficulty of solving large-scale cases, a solution method based on the variable neighborhood search algorithm is developed. Considering the decoupling and charging characteristics of AGV-mates, local search operators for the AGVs’ task sequence, the yard crane’s task sequence, and the AGV battery swapping task nodes are designed. Finally, the efficiency and effectiveness of proposed solution and operators are verified through a series of numerical experiments. This paper presents practical equipment scheduling solutions and management strategies, compared to a single charging or swapping mode, the charging-swapping mode proposed in this paper has a significant improvement in the no-load cost and the delay cost.