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The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. For automated container terminals, the effective integrated scheduling of different kinds of equipment such as quay cranes (QCs), automated guided vehicles (AGVs), and yard cranes (YCs) is of great significance in reducing energy consumption and achieving sustainable development. Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks, a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task. A solution method based on a novel bi-level genetic algorithm (BGA), in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs, respectively, is designed. The validity of the model and the algorithm is verified by simulation experiments, which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared. The results show that, for the given task, the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization, and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged. Comparison results indicate that our proposed approach could efficiently find solutions within 6% optimality gaps. Energy consumption is dropped by an average of 15%. |
