A simulation framework for studying blocking effects in warehouse systems with autonomous vehicles
by Debjit Roy; Ananth Krishnamurthy; Sunderesh S. Heragu; Charles J. Malmborg
European J. of Industrial Engineering (EJIE), Vol. 10, No. 1, 2016

Abstract: Autonomous vehicles-based storage and retrieval systems (AVS/RS) have been shown to offer greater flexibility to improve cycle time and throughput capacity in the transfer of unit loads in high-density storage areas of warehouses. In these systems, loads are transferred by autonomous vehicles that move horizontally along aisles and cross-aisles within a tier, while lifts support vertical movement of loads between tiers. For analytical tractability, prior studies on performance evaluation of AVS/RS have ignored the blocking effects of vehicles and lifts while estimating throughput capacity and cycle times. To evaluate the effects of blocking on system performance, this paper first develops protocols to address vehicle blocking that are subsequently incorporated in a detailed simulation model. The blocking effects are studied for a variety of tier configurations that differ in depth/width ratio, number of locations, number of available vehicles, and transaction arrival rates. Results suggest that blocking delays could account for 2%-20% of the transaction cycle times. [Received 17 October 2013; Revised 28 August 2014; Revised 23 December 2014; Accepted 2 April 2015]

Online publication date: Thu, 03-Mar-2016

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

 
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the European J. of Industrial Engineering (EJIE):
Login with your Inderscience username and password:

Username:        Password:          Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email subs@inderscience.com