Open Access

ARTICLE

AGV Scheduling and Bidirectional Conflict-Free Routing Problem with Battery Swapping in Automated Container Terminals

He Huang, Jin Zhu^*

Institute of Logistics Science and Engineering, Shanghai Maritime University, No. 1550, Haigang Avenue, Pudong New Area, Shanghai, 201306, China

* Corresponding Author: Jin Zhu. Email:

Computer Modeling in Engineering & Sciences 2025, 144(2), 1717-1748. https://doi.org/10.32604/cmes.2025.068384

Received 27 May 2025; Accepted 25 July 2025; Issue published 31 August 2025

Abstract

Automated guided vehicles (AGVs) are key equipment in automated container terminals (ACTs), and their operational efficiency can be impacted by conflicts and battery swapping. Additionally, AGVs have bidirectional transportation capabilities, allowing them to move in the opposite direction without turning around, which helps reduce transportation time. This paper aims at the problem of AGV scheduling and bidirectional conflict-free routing with battery swapping in automated terminals. A bi-level mixed integer programming (MIP) model is proposed, taking into account task assignment, bidirectional conflict-free routing, and battery swapping. The upper model focuses on container task assignment and AGV battery swapping planning, while the lower model ensures conflict-free movement of AGVs. A double-threshold battery swapping strategy is introduced, allowing AGVs to utilize waiting time for loading for battery swapping. An improved differential evolution variable neighborhood search (IDE-VNS) algorithm is developed to solve the bi-level MIP model, aiming to minimize the completion time of all jobs. Experimental results demonstrate that compared to the differential evolution (DE) algorithm and the genetic algorithm (GA), the IDE-VNS algorithm reduces fitness values by 44.49% and 45.22%, though it does increase computation time by 56.28% and 62.03%, respectively. Bidirectional transportation reduces the fitness value by an average of 10.97% when the container scale is small. As the container scale increases, the fitness value of bidirectional transportation gradually approaches that of unidirectional transportation. The results further show that the double-threshold battery swapping strategy enhances AGV utilization and reduces the fitness value.

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Keywords

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