Solving the Joint Order Batching and Picker Routing Problem for Large Instances

In this work, we investigate the problem of order batching and picker routing in warehouse storage areas. These problems are known to be capital and labour intensive, and often contribute to a sizable fraction of warehouse operating costs. Here, we consider the case of online grocery shopping where orders may consist of dozens of items. We present the problem introduced and tackle the issue of solving the problem heuristically with proposed methods of solving that utilize batching and routing heuristics. Instances with up to 50 orders were solved heuristically in large simulated warehouse instances consisting of 8 to 30 aisles, with 1 to 4 blocks. The proposed methods were shown to have relatively short computation times as compared to optimally solving the problem in. In particular, we showed that a proposed method which utilizes an optimal solver for routing yielded poorer results than methods that utilize routing heuristics.