Designing an automated storage/retrieval system with a single aisle-mobile crane under three new turnover based storage policies

Abstract

ABSTRACT This article considers a multi-aisle AS/RS employing a single aisle-mobile crane and develops analytical travel time models for three new storage policies with turnover-based product allocation to aisles. In addition to product turnover, these storage policies also take into account the demand skewness and the characteristics of storage and transport equipment. Based on the proposed travel time models, analytical expressions are derived to determine the physical dimensions of the AS/RS that are optimized with respect to crane travel time. AS/RS designs employing the newly developed storage policies are compared with designs employing three other (non-turnover based) storage policies, using a design methodology proposed in a recent study. The analysis shows that among the three turnover-based storage policies, class-based storage assignment performs better than full turnover-based storage policy when subjected to different evaluation criteria. It is concluded that the inclusion of storage policies in the AS/RS design process, is highly beneficial in the selection of the right storage and transport equipment.