A note about a transition of Ratliff and Rosenthal's order picking algorithm for rectangular warehouses

TL;DR

This paper examines the order picking problem in rectangular warehouses, showing that optimal tours do not need to double cross aisles, refining previous algorithms for more efficient routing.

Contribution

It proves that in rectangular warehouses, minimum tours can avoid double crossing aisles, improving upon Ratliff and Rosenthal's algorithm.

Findings

Optimal tours in rectangular warehouses do not require aisle double crossings.

The result simplifies the structure of minimum length tours.

Improves efficiency in warehouse order picking algorithms.

Abstract

In the order picking problem, a picker has to collect a number of products in a warehouse with a minimum length tour. Ratliff and Rosenthal gave a linear algorithm solving the order picking problem in the case where the warehouse has two cross aisles. Their algorithm allow the tour to double cross an entire aisle. We prove that, in rectangular warehouses, there always exists a minimum length tour which doesn't double cross an aisle.