Variable Neighborhood Search strategies for the Order Batching Problem

The Order Batching Problem is an optimization problem belonging to the operational management aspect of a warehouse. It consists of grouping the orders received in a warehouse (each order is composed by a list of items to be collected) in a set of batches in such a way that the time needed to collect all the orders is minimized. Each batch has to be collected by a single picker without exceeding a capacity limit. In this paper we propose several strategies based on the Variable Neighborhood Search methodology to tackle the problem. Our approach outperforms, in terms of quality and computing time, previous attempts in the state of the art. These results are confirmed by non-parametric statistical tests.