A Multi-Objective Model for Minimizing Makespan and Total Travel Time in Put Wall Based Picking Systems

In this study, a multi-objective order batching and picker routing model for minimising the total travel time and makespan in a put wall-based picking system is proposed. A put wall is a hardware composed of containers that is usually used as a sorting station. Put walls usually have limited capacity and can accommodate only a part of received orders at a time. Thus, in put wall-based picking systems, order batching and picker routing should be considered along with the scheduling of the orders on the put wall. To solve the problem, a genetic algorithm (GA), a coevolutionary genetic algorithm (COGA) and an archived multi-objective simulated annealing (AMOSA) are proposed. It is found that GA and COGA offer a more diverse set of solutions to the problem compared to AMOSA.