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.     

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.     

自动化立体仓库中载人联机可视化拣选方案及其性能分析

提出了一种新颖的利用网络技术和触摸屏进行载人巷道堆垛机上的可视化拣选操作方案，配合存储货位分配策略和执行批量拣选作业的优化顺序方式，可以提高自动化立体仓库中载人拣选作业方式的工作效率，增加拣选操作的吞吐率，在概述了这种新方案的实现框架之后，给出了这种方案的性能模型，并对具有动态作业插入时的系统性能进行了分析。     

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.     

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。     

Dynamic selection of sequencing rules for a class-based unit-load automated storage and retrieval system

This paper studies dynamic selection of sequencing rules for a class-based unit-load automated storage and retrieval system (AS/RS). A multi-pass and genetic algorithm (MPGA) simulation system is developed and it divides storage and retrieval requests or dual commands into a series of blocks, and then conquers each block to find the most promising combination of sequencing rules. These rules are first come first served (FCFS), shortest total-travel time (STT) and shortest due time (SDT), and they can be chosen dynamically in any decision points in the system. An experiment shows that our approach with dynamic rules is much better than those approaches with any single rule used from the beginning to the end in the whole system. The results of this study provide a better way to control and manage the operation of AS/RS.     

基于FMS的自动化立体仓库监控系统开发与应用术

为了实现对基于柔性制造系统（FMS）的自动化立体仓库（AS／RS）的监控与管理,以浙江机电职业技术学院示范院校建设FMS项目为背景,根据具体实验教学的要求,进行了自动化立体仓库集成监控系统设计,实现了一套功能完备、规范化、工程化的集成监控软件。研究结果表明,该系统的运行效果令人满意。     

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.     

自动化立体仓库中输送机控制系统研究

本文以某空港配餐公司自动化立体仓库为例,介绍了输送机在仓库中的应用。在立体仓库出入库工艺流程的基础上,分析设计了全自动模式下输送机出入库的步进流程图,并对不同工作模式下输送机的工艺流程进行了分析。     

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.     

烟丝原料立体仓库堆垛机出入库作业优化研究

为了提高烟丝原料立体仓库堆垛机的作业效率,解决多台堆垛机作业不均衡问题,提出了以各堆垛机作业时间总和最小与作业时间均衡为目标的出入库作业优化模型.在该模型中,用出入库优化作业的规则替代原有作业规则.为了寻求最佳的出入库货位序列,该模型通过构建货位坐标系,采用堆垛机在全速和减速运行状态下联合作业和单作业两种模式的作业时间计算方法,提高了出入库的作业效率.在相同参数下,对一个具体烟丝立体仓库实例进行了作业优化前后的比较.结果表明,通过采用优化作业方法,作业效率每小时可以提高82个烟包,各堆垛机的作业不均衡性大为减小.     

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。     

Scheduling decisions in FMS using a heuristic approach

The paper deals with the multilevel scheduling decisions of a Flexible Manufacturing System (FMS) to generate realistic schedules for the efficient operation of the FMS. The primary concern of an Operations Management System (OMS) for a FMS is production scheduling, Material Handling System (MHS) scheduling, Automated Storage/Retrieval System (AS/RS) operation and control and tool management. Scheduling is a critical issue and determines how efficiently the production resources are utilised and how the selected parts are affected in the system. In this paper, the integrated scheduling of FMS, namely, the production scheduling conforming with the MHS scheduling, is addressed. An enumerative heuristic is used, namely Giffler and Thompson, which is an evolutionary combining a Genetic Algorithm (GA) and a stochastic neighborhood search technique using a Simulated Annealing (SA) algorithm is employed.A. Noorul Haq received his PhD in Manufacturing Management from the Indian Institute of Technology (IIT), New Delhi, India, a Master of Engineering degree from Madras University, and a Bachelor of Engineering degree from Annamalai University, India. He is currently an assistant professor in the Department of Production Engineering, Regional Engineering College, Tiruchirappalli 620015, India. His research interests include aggregate production planning, facility layout and scheduling and optimisation techniques.T. Karthikeyan received his Master's degree from Bharathidhasan University. Currently, he is a research scholar in the Department of Production Engineering, Regional Engineering College, Tiruchirappalli 620015, India. His research interests includes facility layout, FMS and simulation.M. Dinesh received his bachelor's degree in engineering from Bharathiar University, India and is currently working on his master's degee in engineering in the Department Of Production Engineering, Regional Engineering College, Tiruchirappalli 620015, India. His current research interests are in optimisation techniques, facility layout and scheduling.     

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。     

Dual commands dispatching of a class-based unit-load automated storage and retrieval system using multi-pass simulation with generic algorithm

A simulation system with the approach of multi-pass and genetic algorithm (MPGA) is developed for dispatching dual commands by a stacker machine in a unit-load/class-based automated storage and retrieval system (AS/RS). Three single-rules, FCFS/STT, SDT/STT, and STT_bk, are run individually by a single-pass simulation and served as the benchmarks to compare with the performances of three kinds of the MPGA approach. All experiments, singles and MPGA, start with the same initial system states and run with the same input data streams. Due to a larger solution space for the optimal search and an iterative searching method, the MPGA approach greatly improves the performances of our AS/RS model, compared with traditional approaches.     

自动化立体仓库控制系统设计与实现

本文介绍的自动化立体仓库控制系统采用由一台工业控制计算机和3台PLC怕集散型控制网络,实现了集监控、调度、诊断、货位分配、堆垛机运行参数给定等功能于一体的自动化立体仓库控制系统和堆垛机制系统以及立体仓库数据库管理系统。工业现场运行证明了这种设计、控制思路的先进性。     

重力式立体仓库管理系统核心模块设计

应用已有的自动化立体仓库技术,同时结合数据库技术、无线网络技术、条形码识别技术、计算机控制技术等相关技术,针对重力式自动化立体仓库“先进先出”（FIFO）的特点,提出了重力式立体仓库管理系统的总体框架并设计了系统的核心模块。应用表明该系统为重力式立体仓库的自动化管理提供了一种解决方案,能有效提高仓库运行效率达40％以上。     

Reliability analysis of flexible manufacturing systems

High productivity is the primary goal of flexible manufacturing systems (FMSs) in which semi-independent workstations are integrated using automated material-transport systems and hierarchical local networks. Availability of various subsystems and of the system as a whole is a prerequisite for achieving functional integration as well as high throughput. An FMS also has inherent routing and operation flexibilities that provide it with a certain degree of fault tolerance. A certain volume of production can thus be maintained in the face of subsystem (i.e., machines, robots, material handling system, etc.) failures. In this article, we propose two reliability measures, namely, part reliability (PR) and FMS reliability (FMSR) for manufacturing systems and present algorithms to evaluate them. We also consider the dynamic or time-dependent reliability analysis as a natural generalization of the static analysis. The methods outlined use an algorithm that generates process-spanning graphs (PSGs), which are used to evaluate the reliability measures.     

A methodology for the implementation of automated measuring stations in flexible manufacturing systems

This paper presents a methodology for the inclusion of an automated measuring station in an existing flexible manufacturing system (FMS) by treating the measuring station as a workstation integrated into the FMS. This approach causes minimal distortion of the FMS work functions and does not depend on the control algorithms implemented on the system. A case study based on an FMS located at the Aeronautical Centre is presented. The FMS used in the case study is called CFF-ETSIA. This system contains the main elements needed in a FMS: two computer numerical control machine tools for machining and two industrial robots for handling and manipulating. The measuring station in the case study is implemented with one of the robots used to perform the necessary actions of measurement and manipulation.     

APPROACH TO DISPATCHING FMS TOOL SYSTEM

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