Multiple Deep Layout of Robotic Mobile Fulfillment System

The existing studies on the robotic mobile fulfillment systems (RMFS) have analyzed robot route planning, throughput and layout of RMFS based on single deep layout. As land becomes more expensive and the demand to warehouse is increasing, it's essential to consider multiple deep layout to realize compact storage. This paper applies compact storage strategy to traditional parts-to-picker storage system. We develop a semi-open queuing network model (SOQN) to analyze the RMFS with multiple deep layout. The performance indicators such as system throughput and robot utilization are obtained. Our work can provide valuable suggestions for designing compact RMFS, such as which kind of layout (n× m) of block benefits for throughput, how many robots and workstations are required to reach the given throughput under the limited warehouse area and so on.