Dynamic crane scheduling for green automated warehousing: learning-based simulation-optimization approach
摘要
Global e-commerce growth forces traditional warehouses to shift from manual to fully automated operations. One popular way is to adopt Automated Storage and Retrieval System (AS/RS). However, AS/RS consumes a significant amount of energy to load/unload bulky and heavy items. One way to reduce AS/RS energy usage is by optimizing the crane scheduling, as it plays a crucial role in determining the sequence of tasks to be completed. This study proposes a novel dynamic scheduling for minimizing energy consumption while ensuring responsiveness based on Learning-based Simulation–Optimization (LSO) approach. LSO integrates Discrete-Event Simulation as environment and Deep Reinforcement Learning as agent which is optimized by Non-Dominated Sorting Genetic Algorithm II (NSGA-II) to cope with multi-objective problem. For the experiment, a single AS/RS was modeled virtually for training and testing under demand and supply uncertainties. The LSO approach is then compared with other well-known policies such as First Come First Serve, Nearest Neighbor, and Shortest Leg. The result shows that the LSO approach statistically outperforms other policies for both objectives, leading to greener and more responsive operations. Finally, managerial implications are provided where the LSO approach improves AS/RS utilization leading to more robust operation with the capability in providing real-time decisions.