Sequencing methods for automated storage and retrieval systems with dedicated storage

In this paper, we study the effect of sequencing storage and retrieval requests on the performance of automated storage and retrieval systems (AS/RS) where a storage request is assigned a predetermined storage location. By exploiting this unique operating characteristic, we present several optimum and heuristic sequencing methods under static and dynamic approaches. Applications of such sequencing methods include unit-load AS/RS with dedicated storage, miniload AS/RS, and potentially unit-load AS/RS with randomized storage. We find that the sequencing methods can significantly reduce travel time by a storage and retrieval machine, thereby, increasing throughput, and that the dynamic heuristic method is simple and fast, yet considerably outperforms the others.