Browsing by Author "Akpunar, Anil"

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Citation - WoS: 60
Citation - Scopus: 69
A tool for time variance and energy related performance estimations in a shuttle-based storage and retrieval system
(Elsevier Inc. usjcs@elsevier.com, 2018) Banu Yetkin Yetkin Ekren; Anıl Akpunar; Zaki Sari; Tone Lerher; Akpunar, Anil; Lerher, Tone; Ekren, Banu Y.; Sari, Zaki
The aim of this study is to present a tool that can calculate critical performance measures of different Shuttle-Based Storage and Retrieval System (SBS/RS) designs. Specifically our aim is to develop an analytical model-based tool that can estimate the mean and variance of travel time of lifts and shuttles as well as the mean amount of energy consumption and energy regeneration per transaction for a pre-defined SBS/RS design. The methodology illustrated in this paper can also be utilized for any system having a straight discrete travel pattern with equal distance stop points. We are motivated in this study by a relatively new automated storage and retrieval technology SBS/RS. By the provided tool one can evaluate these systems’ performance promptly by changing the input design parameters (e.g. discrete travel lengths velocity of vehicles acceleration/deceleration of vehicles number of tiers number of bays etc.) of these systems. The analytical models used in the tool are verified via simulation for several SBS/RS design scenarios. As a result it is found that the proposed tool produces highly accurate results specifically less than 1% Absolute Percentage Error from the simulation results. © 2018 Elsevier B.V. All rights reserved.
Citation - Scopus: 11
Energy efficient design of autonomous vehicle based storage and retrieval system
(Institut za Istrazivanja, 2017) Anıl Akpunar; Banu Yetkin Yetkin Ekren; Tone Lerher; Yetkin Ekren, Banu; Akpunar, Anil; Lerher, Tone
Autonomous warehousing is moving beyond traditional crane-based AS/RS technologies on the way to autonomous vehicle (AV) based AS/RS (AVS/RS) technologies. AVS/RS proposes substantial flexibility with respect to throughput capacity in the transfer of unit loads in high density storage areas due to having opportunity in changing the number of AVs in the system. Because of recent trend in ecological concern an efficient AVS/RS warehouse design should not only consider minimization of cycle time of a transaction to process but also consider the minimization of energy consumption in the system. In this study we explore energy minimum AVS/RS warehouse design providing maximum utilization of resources in the system. We consider rack design in terms of number of aisles tiers and bays as well as number of AVs as decision variables in the design and energy minimization as objective function. We completed 81 simulation experiments for different levels of those decision variables and provide the results via a histogram graph. © 2023 Elsevier B.V. All rights reserved.