Cycle time models for single/double carousel system

The carousel storage system is an automated storage/retrieval system; it has been widely used in a broad range of applications. This paper examines the throughput performance of the single/double carousel system in which a storage/retrieval machine performs pickup/discharge operations. As a job dispatch and control rule, it is assumed that the information on the rack location of the succeeding job orders is available; this assumption commonly holds in real-world operations. Based on a randomized storage assignment policy, cycle time models are developed for single and dual commands. The value of the information on the succeeding jobs is evaluated in terms of the system efficiency. Also, the effects of the rack shape factor and pickup/discharge time of the storage/retrieval robot are analyzed with the help of sample problems.