Formulating and solving the integrated batching, routing, and picker scheduling problem in a real-life spare parts warehouse

Abstract

New market developments increase the complexity of managing order picking operations. Integrating order picking planning problems enables warehouse managers to organize order picking operations more efficiently. This paper provides a decision support tool that integrates and solves the three main operational order picking planning problems (i.e., order batching, picker routing, and picker scheduling). Different from other studies, the objective is to increase order picking efficiency while ensuring a high customer service level. The new integrated planning problem accounts for order due times, a limited availability of order pickers, as well as a high-level storage locations, to ensure the applicability in practice. An iterated local search algorithm is introduced to solve the problem effectively and efficiently. Moreover, a real-life case shows the substantial performance benefits gained from integrating batching, routing, and picker scheduling.