A method for efficiently routing order pickers in the leaf warehouse

Abstract

Warehouse order picking is a critical operation for every supply chain because of its direct influence on customer satisfaction and the high time investment that is usually required for completing it. Hence, improving order picking efficiency can enhance both customer satisfaction and warehouse throughput. The most critical step in order picking is the travelling along the aisles of the warehouse, which accounts for a major share of the total warehouse operating cost. To minimize this cost for the special case of a warehouse with a leaf layout, the paper at hand proposes an efficient optimal order picker routing policy based on an Eulerian graph and a dynamic programming procedure. It further develops four simple routing heuristics, referred to as leaf S-shape, leaf return, leaf midpoint, and leaf largest gap, for guiding the order picker through the leaf warehouse. The performance of the routing heuristics is compared to the exact algorithm proposed in this paper in a systematic numerical experiment. Finally, we present some managerial insights for managing order picking in the leaf warehouse.