Performance comparison of two material handling systems: AVS/RS and CBAS/RS

Abstract

The purpose of this study is to compare the performance of two material handling systems (MHSs) – autonomous vehicle storage and retrieval systems (AVS/RSs) and traditional, crane-based, automated storage and retrieval systems (CBAS/RSs) – with respect to key performance measures. First, the two MHSs are simulated using ARENA 12.0, commercial software, via 198 experiments based on the rack configurations of the warehouses, number of storage and retrieval (S/R) devices and S/R transaction rates. Five performance measures are considered – average flow time, S/R device utilisation, average waiting time in S/R device queue, average number of jobs waiting in S/R device queue and cost. We also complete a paired-t test comparison to find out the best warehouse design based on cost, flow time and utilisation of the S/R devices. An examination of the results, specifically the flow time of the S/R devices, suggests that in many cases the AVS/RS performs better than the CBAS/RS. However, the best design, when the system costs are considered, is obtained with a CBAS/RS.

Keywords:

• AVS/RS
• AS/RS
• unit load storage and retrieval
• simulation
• performance analysis

Acknowledgments

This material is based upon work supported by the National Science Foundation under Grant No. CMMI 0522798 and CMMI 0946706. We are grateful to NSF for its support. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.