Modeling Single-Picker Routing Problems in Classical and Modern Warehouses

The standard single-picker routing problem (SPRP) seeks the cost-minimal tour to collect a set of given articles in rectangular single-block warehouse with parallel picking aisles and dedicated storage policy, that is, each stock-keeping unit is only available from one location warehouse. We present compact formulation forgoes classical subtour elimination constraints by directly exploiting two properties an optimal used dynamic programming algorithm published seminal paper Ratliff Rosenthal. extend three important settings prevalent modern e-commerce warehouses: scattered storage, decoupling picker cart, multiple end depots. In numerical studies, our outperforms existing SPRP formulations literature proves able solve large instances within short runtimes. Realistically sized extensions can also be solved low computational effort. For we note rough tendency runtimes increase longer pick lists or higher degree duplication. addition, find cart lead substantial cost savings depending on speed capacity when traveling alone, whereas additional depots have rather limited benefits Summary Contribution: Efficiently order pickers great practical interest because costs make up part operational costs. case aisles, highly effective modeling approach covers—in addition setting—several order-picking strategies employed this way, provide practitioners as well scientists easy quick way implementing high-quality solution for described settings. shed some light different experiments.