Energy efficiency model for the mini-load automated storage and retrieval systems

In this paper, the energy efficiency model for the mini-load AS/RS is presented. As the existing models of AS/RS apply to already well-known objectives (minimum travel time, maximum throughput and minimum cost), the energy efficiency model for the mini-load AS/RS is proposed and discussed. According to global trends in material handling and warehousing, the design process should encompass not only the application of the equipment with fastest drives but should also consider the energy and environment aspect on the installed equipment. The proposed energy efficiency model for the mini-load AS/RS enables reduction of energy consumption and consequently the CO₂ emission, which is good from the economic and environmental point of view. We sincerely hope that the energy and environment aspect will indubitably bring changes into planning of warehouses and will mean great challenge for those who are engaged in the planning process.     

Dynamic availability-oriented control of the automated storage/retrieval system. A computer integrated manufacturing perspective

Dynamic scheduling of the storage/retrieval (S/R) requests and increasing the utilization of the storage spaces, are the two common approaches to improve the efficiency of the automated storage/retrieval systems (AS/RS) in industry practice. However, the actual improvement of the AS/RS has to be justified from the perspective of computer integrated manufacturing system (CIMS) because the ultimate objective of the AS/RS is to assist the CIMS in enhancing its material handling efficiency as well as synchronizing the production. Targeting on this crucial requirement, a dynamic availability-oriented controller (DAOC) is developed in this paper to minimize the mean request fulfilment time of the AS/RS. Firstly, while considering the three types of critical dynamic constraints from the CIMS’ shop floor: the availabilities for both machines and the AS/RS, the process plan of the product, and the production schedule, DAOC is capable of determining the optimal execution sequence of the S/R requests issued from the CIMS and activating dynamic storage space consolidation commands of the AS/RS. Secondly, simulation experiments are conducted and the results show that DAOC successfully improves the S/R request control scheme of the traditional class-based assignment method and significantly outperforms four comparable approaches under various CIMS configurations.     

Simultaneous optimisation of control factors in automated storage and retrieval systems and FMS using stochastic coloured Petri nets and the Taguchi method

Automated storage and retrieval systems (AS/RS) are playing an important role in modern manufacturing systems such as flexible manufacturing systems (FMS). The integration of AS/RS systems and FMS is very complex owing to the complexity of the individual elements. Stochastic coloured petri nets (SCPN) can be used to model, simulate and analyse such a system efficiently and realistically. In this paper, SCPN based simulation, aided by the Taguchi method of design of experiments, has been used for analysing the influence of important factors on makespan, unproductive travel time, and the mean flow time, and is supported by an example.     

Storage assignment optimization in a multi-tier shuttle warehousing system

The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem(TSP), which has been widely applied in the conventional automated storage and retrieval system(AS/RS). However, the previous mathematical models in conventional AS/RS do not match multi-tier shuttle warehousing systems(MSWS) because the characteristics of parallel retrieval in multiple tiers and progressive vertical movement destroy the foundation of TSP. In this study, a two-stage open queuing network model in which shuttles and a lift are regarded as servers at different stages is proposed to analyze system performance in the terms of shuttle waiting period (SWP) and lift idle period (LIP) during transaction cycle time. A mean arrival time difference matrix for pairwise stock keeping units(SKUs) is presented to determine the mean waiting time and queue length to optimize the storage assignment problem on the basis of SKU correlation. The decomposition method is applied to analyze the interactions among outbound task time, SWP, and LIP. The ant colony clustering algorithm is designed to determine storage partitions using clustering items. In addition, goods are assigned for storage according to the rearranging permutation and the combination of storage partitions in a 2D plane. This combination is derived based on the analysis results of the queuing network model and on three basic principles. The storage assignment method and its entire optimization algorithm method as applied in a MSWS are verified through a practical engineering project conducted in the tobacco industry. The applying results show that the total SWP and LIP can be reduced effectively to improve the utilization rates of all devices and to increase the throughput of the distribution center.     

自动化立体仓库堆垛机拣选作业调度研究

将堆垛机拣选作业调度归纳为旅行商问题，并从遗传算法角度，研究了求解堆垛机拣选作业调度最优路径的具体方法。经过仿真试验验证，这一方法完全可行。     

Innovative application of an integrated multi-level conveying device to a mobile storage system

Although the mobile storage system (MSS) makes better use of available space, it has the disadvantage of requiring complete manual operation. This leads to slow storage and retrieval speed, high costs, and frequent error. To overcome the problems inherent in manual operation in existing MSSs, this paper proposes an innovative mobile automated storage/retrieval system (M-AS/RS) using an integrated multi-level conveying device (IMCD) for automated item-picking operation. Through appropriate sequencing, the paper simulates the picking of items in batch orders. The paper then presents a comparative analysis of the proposed M-AS/RS model with existing MSS models concluding that the former has a better performance than the latter. The M-AS/RS model proposed by this paper can provide a practical solution to overcome the deficiencies in existing MSS models.     

Optimal random storage allocation for an AS/RS in an FMS

A flexible manufacturing system (FMS) comprises, automated machine tools, automated material handling, and an automated storage and retrieval system (AS/RS) as essential components. Optimal performance of each element of this system would improve the productivity and efficiency of the total FMS. In this context, this paper attempts to link the operation of the AS/RS with the production schedule and suggests two different classes of algorithms, namely, heuristics and genetic algorithms to improve the performance of the AS/RS operation by allocating the materials with minimum movement of the shuttle.     

AGV schedule integrated with production in flexible manufacturing systems

Flexible manufacturing systems (FMS) comprise, automated machine tools, automated material handling, and automated storage and automated retrieval systems (AS/RS) as essential components. Effective sequencing and scheduling of the material handling systems (MHS) can have a major impact on the productivity of the manufacturing system. The material handling cannot be neglected while scheduling the production tasks. It is necessary to take into account the interaction between machines, material handling systems and computer. In this context, this paper attempts to link the operation of automated guided vehicles (AGV) with the production schedule and suggests a heuristic algorithm that employs vehicle dispatching rules (vdr) for conflict resolution. The vdrs considered in this paper are: shortest operation time (SPT), longest operation time (LPT), longest travel time (LTT) and shortest travel time (STT). The performance of the vdrs in the proposed heuristic is compared with makespan criteria. The results show that the STT provides the best solutions compared to other vdrs.     

自动化立体仓库的应用与物流发展的灰色关联分析

本文将灰色关联分析运用与自动化立体仓库对物流发展的作用研究中,根据研究内容的侧重点,选取了10个物流投入的相关指标,用于分析自动化立体仓库的应用对物流发展的作用,最后以上海市近10年的数据为例进行了实证分析,得出各因素对促进上海物流发展的关联程度,验证了自动化立体仓库对物流发展的作用,以便为上海物流的发展策略提供一些参考。     

基于MCGS组态软件的自动化立体仓库控制系统的开发

通过设计一套自动化立体仓库,达到解决城市用地紧张,降低劳动强度,提高工作效率等的目的。它的控制系统是以西门子PLC作为控制系统的核心,利用MCGS组态软件设计出自动化立体仓库上位机监控界面,MCGS组态软件通过设备驱动程序从现场硬件设备获取实时数据并处理,通过指示灯显示货物是否完成到位,并由操作人员按照要求将控制指令数据送给现场硬件设备,以控制立体仓库码垛机械手的各种动作,实现对货物的自动化存取。     

自动化立体仓库运动控制系统EMI及抗干扰应用策略研究

分析了机场货运站自动化立体仓库输送机、堆垛机等设备运动控制系统电磁干扰的来源及干扰机理,剖析了电磁干扰对控制系统产生的不利影响;对抗干扰应用策略进行了较详细的研究,提出了抑制电磁干扰的多种有效措施,以确保立体仓库各控制系统安全可靠的运行.     

大型周转型自动化仓库的倒库算法

为提高出库效率,优化自动化仓库的货物布局,提出了基于分层序列法思想的自动化仓库倒库优化算法。根据“货物距离出口最近”和“空筐距离出口最远”原则生成仓库货物的最佳布局位置,以单目标序列优化法对倒库作业进行优化。该算法已应用于某机场大型自动化周转仓库监控管理系统,提高了出入库效率。     

立体仓库设计方案的综合评价模型及其应用

提出立体仓库设计方案的评价指标,阐述各评价指标的计算方法,建立了立体仓库设计方案的综合评价模型,并结合实例说明了综合评价模型在立体仓库设计方案选择中的应用。     

Object-oriented graphical modeling of FMSs

Presented in the article is a method for constructing a graphical model of an FMS by using a new modeling tool called JR-net (Job Resource relation-net). JR-net is an object-oriented graphical tool for modeling automated manufacturing systems (AMSs), such as FMSs, FASs, and AS/RSs. As with the object-oriented modeling paradigm of Rumbaugh et al. (1991), the JR-net modeling framework supports the three stages of models: static layout model (object model); job flow model (functional model); and supervisory control model (dynamic model). In this article, the existing JR-net structure (Park 1992, Han et al., 1995) is extended further to make it a graphical tool for FMS modeling. Using the extended JR-net, a step-by-step procedure for constructing a graphical model of FMSs is presented. Also addressed are issues of classifying FMSs in terms of their generic functions and of utilizing the JR-net model of FMSs.     

面向立体仓库群的汽车零部件仓储实时监控系统的应用研究

提出了汽车制造企业零部件物流管理的信息化、集中化理念,构造了依照零部件总成划分的立体仓库群的设备层与控制层的信息交互平台,建立了零部件仓储实时监控与数据采集系统。基于该系统纵向集成搭建企业应用层面的协同工程应用与管理平台,通过与发动机车间、冲压车间、焊装车间、涂装车间、总装车间的各制造执行系统之间的数据共享与联合应用,保障整个制造过程的零部件有效供给,全面实现物流供应链的科学管理,整体上提升汽车制造企业经济效益的有效途径。     

Evaluation and dynamic allocation of AS/RS control rules: A simulation study

The goal of this research is to investigate the performance of an automated storage and retrieval system (AS/RS) which is operated using different control rules. Two phases of study are conducted. Phase 1 evaluates the efficiency of different rules for stacker control, storage-location assignment and job sequencing. Phase 2 studies the impact of these rules on the performance of the AS/RS using a multipass simulation approach. In this paper, the methodology of investigation is discussed, the results are presented and analysed, and suggestions for future study are made.     

面向仓储物流的建模及控制系统设计方法

为提高现代企业仓储物流的设计质量和效率,提出了一种基于资源颜色时序信号的扩展Petri网建模及控制系统设计方法.该方法首先采用资源颜色时序信号的扩展Petri网建立了仓储系统的动态模型,清晰地描述了各种物流活动的顺序、并发,冲突等关系,并结合关联矩阵,阐述了判断死锁和陷阱的方法.该方法建立的模型可根据Petri网运算规则进行保性化简,便于仿真分析和验证,且可直接用于系统可编程逻辑控制器的控制程序设计.最后,以仓储物流控制系统为例,阐述了系统建模及控制设计过程.     

立体仓库控制系统关键技术

针对自动仓储控制系统中调速方式、控制结构、信号传递方式、位置监测和定位方式等关键技术进行了研究,为控制系统设计提供了技术支持。     

Travel-time models for flow-rack automated storage and retrieval systems

In this paper, closed-form travel-time expressions for flow-rack automated storage and retrieval systems are developed. The expressions, which are based on a continuous approach, are compared for accuracy, via simulation, with exact models which are based on a discrete approach. There is no significant difference between the results obtained from the continuous-approach-based closed-form expressions and the ones from the discrete-approach-based exact solutions. The closed-form expressions are easy to calculate due to their simplistic forms, even without a computer, while the exact solutions are extremely complex. On the basis of computation time, the proposed closed-form expressions are extremely practical when compared with the discrete-approach-based expressions, which require extensive computation time. The closed-form travel-time expressions developed in this study can be used to (1) establish performance standards for existing AS/RS, (2) evaluate throughput performance for flow-rack AS/RS alternative design configurations, and (3) compare different storage techniques for improved system performance. Due to their simplistic, yet accurate, definitions, the closed-form expressions, as well as the results of this study, are applicable to industry.     

Design and control of an AS/RS

Automated storage/retrieval systems (AS/RSs) are a combination of equipment and controls which automatically handle, store and retrieve materials (components, tools, raw material and subassemblies) with great speed and accuracy. Consequently, they are widely used in industrial companies to manage products with cost-effective utilization of time, space and equipment. This paper presents a multi-parametric dynamic model of a product-to-picker storage system with class based storage allocation of products. Thousands of what-if scenarios are simulated in order to measure the impact of alternative design and operating configurations on the expected system performance and to identify the most critical factors and combinations of factors affecting the response of the system. Class based storage proves to be a very effective way of both reducing the picking cycle time and maximizing the throughput of the system. The rapid effectiveness of visual interactive simulation (VIS) in supporting the design (redesign) and control of new (existing) warehouses emerges, responding to the need for flexibility which modern companies need in order to adapt to strongly changing operating conditions quickly.