Automatic Reverse Warehousing System: Principal Concepts, Modeling and Optimizing of Shelving and Routing Problems

Warehouses and distribution centers are essential components in supply chain and their management has a particular importance. In the traditional approach for collecting the items of orders in warehouses, operators walk or drive toward the shelves and collect the ordered items. However, since 2006 a new system has been deployed in some large distributing warehouses like Amazon Inc., in which shelves are mounted on mobile platforms and are carried by small mobile robots toward operators who pick the ordered items. Advantages of this system compared to traditional system are increased flexibility, accuracy, and speed of preparing the received orders. On the other hand, the mathematical model of this system –which we call it ‘Automatic Reverse Warehousing System (ARWS)’– is introduces as a trade solution, and no research papers have been published about it. In this paper, this system will be studied from the viewpoint of industrial engineering. Then, its components and their relationship with each other and their two major subproblems, namely, allocation and routing will be identified, and their interrelations will be investigated. The model is solved for minimizing the overall cost and finding the best paths of shelves through a Genetic Algorithm and maximum flow approach.