Formulating and solving integrated order batching and routing in multi-depot AGV-assisted mixed-shelves warehouses

Different retail and e-commerce companies are facing the challenge of assembling large numbers time-critical picking orders that include both small-line multi-line orders. To reduce unproductive picker working time as in traditional picker-to-parts warehousing systems, different solutions proposed literature practice. For example, a mixed-shelves storage policy, items same stock keeping unit spread over several shelves warehouse; or automated guided vehicles (AGVs) used to transport picked from area packing stations instead human pickers. This is first paper combine solutions, creating what we call AGV-assisted systems. We model new integrated order batching routing problem such systems an extended multi-depot vehicle with three-index two-commodity network flow formulations. Due complexity problem, develop novel variable neighborhood search algorithm solve more efficiently. test our methods sizes instances, conclude policy suitable than usual for lines (saving up 62% on driving distances AGVs). Our provides optimal within acceptable computational time.