Optimization of Space Utilization for a Man-On-Board AS/RS Through Applying Modular Cells: A Case Study of a Spare Parts Warehouse

The concept of “design for modularity” has attracted much attention and wide applications as a design principle of complex systems, owing to its capability to obtain new configurations without loss of the system’s functionality or performance. This study investigates an application of modularity in warehouse facilities and more specifically for an automated storage and retrieval system (AS/RS). In terms of flexibility, the conventional rack configurations of AS/RSs using the concept of unit-load are inefficient for the storage of different types and various sizes of loads. Meanwhile, if various sizes of loads are to be stored in the conventional rack configurations, the space utilization will significantly decrease as a result of the increased lost space in each storage cell. In order to cope with these drawbacks, the rack of modular cells for AS/RSs has been introduced in the literature. The specific contribution of this study is an extension and a real-world application of applying modular cells to a man-on-board AS/RS to improve its flexibility and space utilization. For this purpose, a case study of a spare parts warehouse from the steel-making industry is investigated. The results show that the rack of modular cells offers significantly higher flexibility and space utilization than its conventional counterpart using equal-sized non-modular cells, especially with no effect on the system’s functionality.