Travel Time Analysis of an Open-Rack Miniload AS/RS under Class-Based Storage Assignments

Abstract

Automated storage and retrieval system (AS/RS) is one of the major warehousing systems, which is widely used in distribution centers and automated production and can play an essential role in modern factories for work-in-process storage, as well asin integrated manufacturing systems. In this study an open-rack miniload AS/RS with unidirectional-upward mobile loads within the rack is considered. In this system, the stacker crane is used for the retrieval operations and shuffling procedures, while the storage operations are carried out by separate devices namely, storage platforms. The proposed AS/RS has one storage platform for each rack to unload several loads at the same time into the rack. Travel time of the proposed AS/RS is analyzed under class-based storage policy by means of Monte Carlo simulation. The results of this study can be used as guidelines for the design and analysis of this kind of AS/RS. Index Terms—Automated storage and retrieval systems (AS/RS), Open-rack miniload AS/RS, travel time, monte carlo simulation.