Fixed and rolling batching for order picking from multiple carousels

Abstract

The carousel is an important automated storage and retrieval system. Customer orders to be collected from carousels are grouped into batches and the orders of a batch are collected simultaneously. We study two batching methods for picking from multiple carousels: (i) fixed batching, where all orders belonging to a batch are collected before the next batch is started, and (ii) rolling batching, where each time an order belonging to the current batch is completed, it is immediately replaced by a new order. For these methods, the main decision is respectively to allocate orders to different batches and to define a sequence for adding orders into batches. With the objective of minimising the total completion time, we develop models for fixed and rolling batching. Thanks to our collaboration with the company KLS Logistic Systems, we use real data to test and prove the efficiency of our models. With comparison to current batching strategies of real companies and to benchmark heuristics, our models yield a considerable time saving. Our findings also indicate that an increase in order size favours the rolling batching over the fixed batching. The models developed in this paper have been implemented and are currently being used in practice.

Keywords:

• Warehousing
• carousels
• fixed and rolling batching
• order picking
• analytical and numerical modelling

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Nicolas Lenoble

Nicolas Lenoble holds a PhD in Industrial Engineering acquired in 2017 and is currently project manager at Expleo. Always interested in warehousing optimisation, he is continuously involved in projects is this field, along with digitalisation of processes.

Ramzi Hammami

Ramzi Hammami is full professor of Supply chain management at Rennes School of Business and director of the area of excellence in Green, Digital, and Demand-driven Supply Chain Management. He holds a PhD in industrial engineering. He works on the application of operations research and decision sciences in operations and supply chain management.

Yannick Frein

Yannick Frein received the degree of Habilitation à Diriger des Recherches in 1991. Currently he is Full Professor at the Institut Polytechnique de Grenoble in the Industrial Engineering department. His research interests are in modelling and performance evaluation of discrete event models, with applications to the design and management of supply chains.