Scheduling AGVs in ports with battery charging and swapping

Efficient scheduling of automated guided vehicles (AGVs) in automated container terminals (ACTs) is crucial to their operations management under the initiative of green port and smart port development. Facing numerous containers, a port operator needs to assign container loading/unloading tasks to AGVs, sequence the tasks for each AGV, and arrange the battery-charging or -swapping activities for the AGVs in a highly efficient manner, which affects the operational performance of the port and further impacts its annual throughput. This study proposes a mathematical model for scheduling AGVs under the battery charging–swapping mixed mode. The model should be solved in a short time, otherwise the proposed methodology cannot apply to realistic port environments. Therefore, an efficient column generation–based solution method is designed for solving the models; a novel label-setting algorithm is also proposed and embedded in the above method for solving the pricing problems in a fast way. Based on two representative ACTs (i.e., the first ACT in China and the largest ACT in the world), numerical experiments are conducted to derive some managerial insights for ACTs’ operations management on AGVs under different battery management modes.