Simulation model of multi-shuttle automated storage and retrieval systems (original) (raw)
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Innovative travel time model for dual-shuttle automated storage/retrieval systems
Computers & Industrial Engineering, 2011
In modern production and distribution systems, the automated storage/retrieval systems (AS/RS), highstorage level systems that reduce labor cost, required floor space and error rate, while increasing product availability, have been widely used since the 1950s. Due to the high-investment costs involved in the development of high-efficient and high-flexible automated storage systems, performance estimation of the systems is both practically and theoretically important. The authors suggest a new method to estimate the travel time of a recently emerging version of AS/RSs, the multi-shuttle systems. The proposal is based on an industrial standard established by the Federation Européenne de la Manutention (F.E.M.). In order to estimate travel times, the authors conduct a Monte Carlo simulation to determine coordinates of two additional representative points which are not given by F.E.M. Then they conduct a new Monte Carlo simulation to compare the results obtained by the method they proposed with those of previous methods and models developed in scientific literature based on Bozer and White formulations. Several real industrial applications demonstrate the validity of proposed method.
Multi-Shuttle Automated Storage and Retrieval System
Review of Industrial Engineering Letters, 2018
Automated Storage and Retrieval Systems (AS/RS) are being widely used in the logistics industry. This typical System, Systems are computer controlled storage systems that can automatically store and retrieve loads. Major advantages of AS/RS include high throughput, efficient use of space, high reliability and improvement of safety. There are some different operational modes in typical system. The choice of operational mode depends on the storage location assignment policy. Shared storage approach is one of these policies. In this approach, the empty space created by an act of accumulation throughout recovery can be quickly filled which conduces to save time and money. This paper examines the joint optimization of (AS/RSs) scheduling in multi-shuttle AS/RSs under shared storage in fuzzy and dynamic environment. From the view of analytical model, the advantage of operational mode under shared storage is verified. For optimization multi-shuttle automated storage and retrieval system to minimize travel time, present a zero-one fuzzy mathematical programming model. Use Genetic algorithm (GA) with Matlab software to solve large-sized problems. Various numerical experiments are conducted to evaluate the performance of the proposed algorithm and investigate the impact of different parameters on computational efficiency. The result indicates that in matters where the primary objective is to reduce travel time cycle, shared storage policy is appropriate. Furthermore, the fuzzy sets theory can be an effective tool to model the uncertainties which are available around the real applications. 1. INTRODUCTION Due to the merits of higher operational efficiency, multi-shuttle automated storage/retrieval systems (AS/RSs) become increasingly popular for storing products in factories and distribution centers. A typical multi-shuttle AS/RS has a series of storage aisles each of which is served by a multi-shuttle storage and retrieval (S/R) machine. The multi-shuttle S/R machine can carry multiple stock keeping units (SKUs) at a time, which implies that performing multiple operations (storage or retrieval) on a trip is feasible. The increase of storage and retrieval operations performed on a trip naturally leads to reducing the empty travel time of the S/R machine. Then the higher operational efficiency can be obtained compared with the single-shuttle AS/RS [1]. Nowadays companies need powerful and up-to-date tools to be able to survive competitions. Stock keeping systems are considered key components in the processes of production and storage of a product in manufacturing organizations and warehouses of large companies. Automated storage systems can play a decisive role in this regard. Manufacturers use fully automated stock keeping systems to improve accuracy and speed in performing storage and retrieval operations of products in the warehouses. Along with the technological progress in the present area, storage systems have grown
Simulation analysis of mini-load multi-shuttle automated storage and retrieval systems
The International Journal of Advanced Manufacturing Technology, 2011
Technological developments in warehouses have changed processes of storage operations, which reflect in short response times of the storage or retrieval of goods, the reduction of stocks and the volume of storage work as well as the automation of the entire warehouse management. Many companies are replacing traditional warehouses with automated storage and retrieval systems, which can be classified into unit-load and mini-load systems. In this paper, the simulation analysis of mini-load multi-shuttle systems is discussed and evaluated. Multi-shuttle systems are based on the quadruple and sextuple command cycle and could therefore achieve higher throughput capacities due to single-shuttle systems. Different analytical models are used by practitioners for designing multi-shuttle systems. The problem arises with the selection of the appropriate analytical model for which the condition of minimal differences with actual circumstances in practice is fulfilled. For the evaluation of the two well-known analytical models, the discrete event simulations have been used. Beside the evaluation of analytical models, the results of simulation analyses showed throughput improvements for triple-shuttle systems according to dual-shuttle systems. The main objective of this paper is to determine the performance of presented models (analytical and simulation models) of multi-shuttle systems, which represents the main share and support in design process of mini-load multishuttle automated storage and retrieval systems.
2014
In this paper, we aim to validate travel time models for single and dual command cycle displacements of lifts and shuttles in a shuttle-based automated storage and retrieval system (SBS/RS) by using experimental computer simulation. The models under consideration take into account acceleration and deceleration delays. We use ARENA 12 software for the simulation modeling. By simulation, we emulate the real functioning of the system. Therefore, we assume that the results from the ARENA simulation are equivalent to the onsite experimentation. Simulation results are very close to those obtained by analytical travel time models. This shows the high precision of these models to predict operations of SBS/RS.These models can be used at design or operation phases to calculate throughput of the system, to compare between different topologies of SBS/RS or with other types of AS/RS to help decision makers to choose among different alternatives of automated storage systems.
Multi-shuttle automated storage/retrieval systems
IIE Transactions, 1997
Multi-shuttle automated storage/retrieval systems have been developed for use in factories and distribution centers since they are more e cient than single-shuttle systems due to less empty travel. This improved e ciency results in more agile support (exible response, less waiting time, etc.) for the production system the storage/retrieval system serves. In this paper we develop analytical models to estimate the throughput in twin-and triple-shuttle systems. An application of the models to an existing triple-shuttle system is presented to illustrate the use of the models and also to illustrate the bene ts gained in terms of decreased waiting time when the existing system is modi ed to utilize a more e ective operating policy.
Shuttle-based storage and retrieval systems (SBS/RS) are an important part of automated warehouses. SBS/RS are often used if troughput demand is high. SBS/RS can have significant advantages compared to crane-based automated storage and retrieval systems (AS/RS) with regard to throughput, energy efficiency and flexibility, depending on the application. Therefore, in the last ten years, the market for SBS/RS has grown considerably. Research of SBS/RS has not been as thorough as in the case of AS/RS. In particular, the development and investigation of different storage policies and the resulting throughput increases and reductions in energy consumption during their application have considerable potential. This paper demonstrates the potential for throughput improvement in the application of the storage management policies class-based storage, sequencing of retrieval requests and warehouse reorganization. A simulation model is used to determine the throughput. The results shows that significant optimization of the throughput is achieved by the application of the presented storage management policies.
Simulation-based Energy and Cycle Time Analysis of Shuttle-based Storage and Retrieval System
2016
This study explores the best warehouse design for shuttle-based storage and retrieval system (SBS/RS) minimizing average energy consumption per transaction and average cycle time per transaction, simultaneously. For that we provided average energy consumption per transaction versus average cycle time per transaction graphs, for different design scenarios of the studied SBS/RS warehouse. In the design concept, we considered, rack design in terms of number of bays, number of tiers, number of aisles, as well as velocity profiles of lifts in the system. We completed 144 number of experiments by simulation to see the trade-offs based on the design scenarios and provided them by two separate graphs. The results show that while the SBS/RS warehouse has low number of tiers, it has low energy consumption per transaction as well as low average cycle time per transaction in the two lift velocity scenarios.
Performance Analysis of Compact Storage Systems with Autonomous Shuttles
2014
Modern warehouses are progressively expected to respond efficiently and responsively to varying customer demand. Conventional Automated Storage and Retrieval Systems (AS/RS) have been recognised as often expensive and inflexible in handling fluctuating demand volumes. However, in the last decades, new systems, i.e. Automated Vehicle Storage and Retrieval Systems (AVS/RS), have emerged with the potential benefit of both presenting low operational costs and allowing inherent volume flexibility. More recently, shuttle-based compact storage systems using lifts instead of cranes have been introduced combining the features of an AVS/RS with compact storage. This research is a first attempt to study these systems by analysing their performance through analytical modelling. The system is modelled as a multi-class semi-open queuing network with class switching. The model can handle both specialised and generic shuttles. Innovative methods are used to solve the developed models. The accuracy ...
Analytical travel time models for multi aisle automated storage and retrieval systems
The International Journal of Advanced Manufacturing Technology, 2006
Multi aisle automated storage and retrieval systems correspond to multiple picking aisles served by a single storage and retrieval machine. These systems are used in practice when the need for pallet places is high and the throughput capacity is relatively low. Therefore, considerable savings of initial investment costs due to single aisle systems can be achieved using such systems. The objective of the presented study is to develop analytical travel time models for multi aisle automated storage and retrieval systems considering the operating characteristics of the storage and retrieval machine. With the proposed analytical travel time models, average travel time of the storage and retrieval machine, from which the performance of multi aisle automated storage and retrieval systems can be evaluated is determined. A simulation model of multi aisle automated storage and retrieval systems was developed to compare the performances of the proposed analytical travel time models. An example of multi aisle automated storage and retrieval systems with five picking aisles was presented for the evaluation purpose. The results show that proposed analytical travel time models perform satisfactory according to the results of simulation analysis and could be very useful tools for designing of multi aisle automated storage and retrieval systems in real-world applications.