Storage-Retrieval Interleaving in Automatic Warehousing Systems

TLDR

The study focuses on a high‑rise automatic warehouse, with results that extend to warehousing systems more broadly. The authors aim to extend prior storage‑assignment rules by incorporating interleaving of storage and retrieval requests. They employ continuous analytical models and discrete evaluation procedures to compare the operating performance of several storage‑assignment/interleaving policies. The policies yield significant reductions in crane travel time and distance, translating into higher throughput capacity and enabling better design trade‑offs between throughput and storage capacity.

Abstract

This paper extends work previously reported on storage assignment rules for automatic warehousing systems to include interleaving; that is, the sequencing of storage and retrieve requests. Using both continuous analytical models and discrete evaluation procedures, this paper compares the operating performance of several storage assignment/interleaving policies. The results indicate that significant reductions in crane travel time (and distance) are obtainable in some real-world and/or previously modeled situations via the proposed storage assignment/interleaving policies. These reductions may be directly translated into increased throughput capacity for existing systems. The storage assignment/interleaving policies may also be used to improve the design of proposed systems to achieve a more desirable balance between throughput and storage capacity. Although the system examined is a high-rise automatic warehouse, the results presented have implications for the warehousing function in general.