The Robotic Mobile Fulfillment System is a newly developed automated, parts-to-picker material handling system. Storage shelves, also known as inventory pods, are moved by robots between the storage area and the workstations, which means that they can be continually repositioned during operations. This paper develops a queueing model for optimizing three key decision variables: (1) the number of pods per product (2) the ratio of the number of pick to the number of replenishment stations, and (3) the replenishment level per pod. We show that too few or too many pods per product leads to unnecessarily long order throughput times, that the ratio of the number of pick to the number of replenishment stations can be optimized for order throughput time, and that waiting to replenish until a pod is completely empty can severely decrease throughput performance.
Progress in Material Handling Research: 2016
Lamballais, Tim; Roy, D.; and de Koster, M.B.M, "A Novel Approach to Analyze Inventory Allocation Decisions in Robotic Mobile Fulfillment Systems" (2016). 14th IMHRC Proceedings (Karlsruhe, Germany – 2016). 13.