Optimal stock picking decisions in automatic storage and retrieval systems

Recent technological developments have brought on a revolution in the design and operation of warehousing systems. Automatic storage/retrieval systems (AS/RS) driven by embedded computers are becoming increasingly more prevalent. The increased use of AS/RS is creating the need for computerized control algorithms to support the scheduling and logistical decisions in such automated warehouses. In this research we explore the problem of deciding which storage locations to retrieve when confronted with a set of discrete orders for a given inventory item. In addition to the normal costs associated with the retrieval decision, this support introduces the cost of a location "breakdown" as a complicating factor in the retrieval decision. The problem is formulated as a type of mixed zero-one integer program. Computational results from a sample set of problems are reported.