Modelling of Rail Guided Vehicles serving an automated parts-to-picker system

An automated parts-to-picker picking system usually consists of an automated warehouse, with Automatic Storage and Retrieval Systems (AS/RS) that retrieve the Stock Keeping Units (SKUs) of the various needed products from their stocking locations, and of a picking area, with human operators or robots that pick the needed items in order to create a mixed shipping unit. The automated warehouse and the picking area are connected by an automated transportation system, which moves the SKUs from the warehouse to the picking stations and vice versa. The transportation system can be, for example, a ring rail conveyor on which various Rail Guided Vehicles (RGVs) are able to carry one SKU at a time. The present paper proposes a preliminary simulative analysis and, then, a mathematical formulation for this transportation system, useful to properly estimate the number of RGVs that are required to fulfill a certain picking throughput. In fact, it is shown that the picking throughput does not increase linearly with the number of vehicles employed, due to congestion issues. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.