Object-oriented approach of MCTPN for modelling Flexible manufacturing systems

Manufacturing industry is facing a stricter challenge than ever before owing to the rapid change in market requirements. Flexible manufacturing systems (FMSs) have a much greater capability than traditional fixed-type production systems for coping with the rapid change. In this paper, a modified coloured-timed Petri net (MCTPN) is developed to model the dynamic activities in an FMS. The MCTPN provides an object-oriented and modular method of modelling manufacturing activities. It includes colour, time, modular and communication attributes. The features of object-oriented modelling allow the FMS to be modelled with the properties of classes, objects, and container trees. Since the system activities can be encapsulated and modularised by the proposed MCTPN, the manufacturing systems can be easily constructed and investigated by the system developers. It makes the concept of software IC possible for modelling complex FMSs. Once all of the MCTPN objects are well defined, the developers need to consider only the interfaces and operations relating to the MCTPN objects. In order to demonstrate the capability of the proposed MCTPN, the FMS in the Manufacturing Automation Technology Research Center (MATRC) of the National Taiwan University will be stimulated and justified by using the proposed MCTPN along with the G2 expert system.     

Object-oriented approach to the specification of manufacturing systems

This paper proposes an object-oriented approach to the specification of manufacturing systems. The specification model is built around a set of concurrent cooperating objects whose behaviour is described using communicating finite state machines. One of the interesting features of this approach is that the system's environment can be included in the model. This allows for rapid prototyping of the system through realistic simulations.     

Object-oriented Petri nets for modelling and analysis of automated manufacturing systems

This paper presents an Object-oriented Petri Net (OPN) approach to model and analyse the dynamic behaviours of an Automated Manufacturing System (AMS). Both the basic and the complete OPN models are introduced to represent the generic and specific dynamic behaviours of an AMS, respectively. Based on the basic OPN model, we need to construct the Object Communication Net (OCNet) for each physical object, and then employ the theory of invariants to perform the deadlock analysis. For an analysed non-deadlock basic OPN model, the complete OPN model for a specific AMS may be effectively derived from it by only including those related system constraints (e.g. part routing, resource capacity), since the basic OPN class library is reusable. A conflict analysis approach is then introduced to identify all the conflicting events involved in the complete OPN model, so that the most suitable control/decision strategy for resolving each conflict event may be suggested. Consequently, a rule-based control software may be implemented directly from the specification of the validated complete OPN model by following a number of transformation rules.     

制造业信息系统多源异构知识集成

为了实现制造业信息系统中各类多源异构的数据、信息和知识层的集成,提出一个全新的可计算框架体系。通过定义一个应用领域的本体论,明确地定义其领域标准词汇和关系。同时,也形式化地定义一个对本体论具体状态进行详细说明的知识库,由此建立一个异构源的信息转化为通用的知识表示模型,解决知识集成过程中结构和语义两方面的异构问题。之后,应用资源描述框架模式(RDFS)作为信息和知识的核心转换技术,进行异构知识的转换和映射,实现异构知识集成。     

Specification methods for material-handling control algorithms in flexible manufacturing systems

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.     

多维度制造工艺信息建模

针对计算机辅助工艺设计系统对工艺信息进行有效组织和表达的需求,总结了工艺信息的相关内容,提出了从版本维、活动阶段维和粒度维构建工艺信息的三维度模型.为更好地组织一定工序活动和版本下的工艺信息,基于此三维度模趔提出工艺信息层的概念,并构建了相应的抽象描述结构.在版本维度和活动阶段维度分别给出工艺信息随版本和工序活动不断演变的表达方法.采用基于"对象一关联"的可扩展数据存储模式,实现了不同粒度信息的存储和扩展.以一个工艺信息实例说明了所提出的三维度建模方法在支持工艺设计与工艺信息管理原型系统模块开发中的应用.     

制造信息全面质量管理研究(一)

从信息角度看,制造企业中一切制造活动都可以视为由一系列不同层次的、不同程度相关联的制造决策/执行/检测和再决策单元Dij组成,制造信息既是决策的依据又是决策的产出,制造信息质量对决策质量有决定性影响。指出了制造信息质量的重要性。为了改善制造企业的市场竞争力,必须获取、产出和有效利用高质量制造信息,减少不良制造信息。阐述了制造信息的主要用途。给出了制造信息的质量变量及其评估方法。着重阐述了对制造信息实施全面质量管理的必要性和可行性。讨论了高质量制造信息的应用特点。     

A decision-making framework model for evaluating flexible manufacturing systems using digraph and matrix methods

In the present work, a methodology based on digraph and matrix methods is developed for evaluation of alternative flexible manufacturing systems. A ‘flexible manufacturing system selection index’ is proposed that evaluates and ranks flexible manufacturing systems for a given industrial application. The methodology is illustrated by an example.     

可重构制造系统建模方法

对可重构制造系统建模方法,包括基于Petri网的可重构制造系统建模、基于排队网络的可重构制造系统建模、基于马尔可夫链的可重构制造系统建模、基于多Agent理论的可重构制造系统建模等方法的研究现状进行了系统的介绍,并进行了分析和比较,最后给出了可重构制造系统建模的发展方向。     

面向对象的机电系统结构及行为建模

针对原理设计阶段机电一体化系统的逻辑结构模型、逻辑/物理行为模型和原理方案表达,提出了基于参考模型的机电一体化系统初步逻辑结构,以及基于统一建模语言(UML)类图的详细逻辑结构(即原理方案表达);提出了基于消息序列图(MSC)的交互行为建模及基于规范和描述语言(SDL)的逻辑/物理行为建模方法,从而基于人类认知客观世界...     

Knowledge-based tool for manufacturing systems design

Knowledge engineering technology has been applied to the construction of a tool which aims to provide support during the complicated process of manufacturing system desing. Based on the ‘controllability engineering’ method, this knowledge-based system is directed towards the analysis and redesigning of manufacturing systems. The approach used in the construction of the CENT system is based on accumulated case experiences which have been implemented on hypermedia tools. Building problems associated with the project are described, alternative solutions to the problems encountered are explored, the project's current status is outlined, and the knowledge-based system's use is detailed.     

Multilevel simulation for advanced manufacturing systems

This paper focuses on the techniques used to generate a multilevel simulation system that can optimise the design, layout, control and performance of a flexible manufacturing system (FMS). It discusses the software structures used to design and implement the simulator, which operates in the following modes: Off-line system-layout optimisation Off-line part-schedule evaluation Off-line control-algorithm evaluation/optimisation On-line state extrapolation and “what if?” testing All of these modes of operation are essential to the efficient running of a complex FMS. The techniques described have been applied and tested on an FMS at the Key Centre for Computer Integrated Manufacture at Swinburne Institute of Technology in Melbourne, Australia.     

机械制造企业车间制造过程信息集成方案研究

在综合分析制造执行系统(MES)技术发展的基础上,结合我国机械制造企业的具体情况,研究机械制造企业车间制造过程、主要功能和信息交换关系,提出通过车间制造过程集成企业的管理和技术系统,建立一种车间制造过程的集成方案,以满足企业的集成需求,并结合案例进行说明.     

面向服务的车间制造过程信息集成运行系统

针对生产过程中车间存在多源异构信息难以有效集成的问题,在分析制造过程信息组织形式特点的基础上,提出了一种面向服务的车间制造过程信息集成运行系统的体系结构。该体系结构以制造过程信息为主要集成对象,以车间制造过程功能服务为核心,利用基于可扩展标记语言的规则映射方法对异构制造过程信息的格式进行同构化处理,为不同服务提供数据支持,并由服务对制造过程信息进行访问控制和管理;在此基础上用模型驱动的方法编排服务并再现业务流程,通过制造过程集成总线对业务流程进行监控和管理;在应用层通过不同视图将生产制造过程展现给不同用户,实现可视化生产。最后,基于上述系统体系结构和实现方法,进行了系统模块开发和应用验证。     

基于MES的生产车间管理信息系统

针对制造企业在实施生产管理信息化过程中存在的问题,提出以制造执行系统(MES)为核心的三层结构———企业资源计划(ERP) /制造执行系统(MES) /过程控制系统(PCS)的生产管理信息化的实施方案,用于解决生产与计划相互脱节的难题,实现了车间的现场调度、生产过程控制、在线质量控制,以及对生产过程中“非常规信息”的控制与管理,加强了制造计划的可执行性。     

生产系统的新发展--可重构的生产系统

随着经济的全球化，企业面临的市场竞争空前激烈。企业为求得生存和发展，不仅要关注产品的创新外发，还必须进行产品生产方式的变革。努力应用新技术、新工艺，推动生产系统不断地发展变化。可重构的生产系统就是美国学者十多年前提出的一种生产系统发展的新模式，并在美国密歇根大学工程学院的工程研究中心进行了比较系统的研究。变革生产系统的目的是提高生产牢，归根到底就是要提高企业的效益和竞争力。这项课题一经提出，立即引起各国制造业界的高度关注。     

A distributed architecture for automated manufacturing systems

The concept of distributed architectures for automated manufacturing systems is presented here. A modular architecture for a logical cell-controller is proposed where shopfloor level modules are incorporated in the cell control system so as to allow active co-operation for distributed decision making and control. Two examples illustrating distributed formulations for specific planning and control are presented. These examples demonstrate the feasibility and potential for distributed architectures for automated manufacturing. This work has been supported by a grant from the Institute of Manufacturing Research, Wayne State University, USA.     

制造系统信息化控制台研究

针对制造系统信息的种类和数量的急剧增加,造成决策人员对大量信息处理和及时做出决策的困难,提出一种面向制造系统的仪表板(dashboard)——制造系统信息化控制台系统,为上述问题的解决提供了支持工具.首先分析了制造系统信息化控制台的内涵,并提出系统的体系结构,在此基础上,分析了实现制造系统信息化平台的关键技术,为系统的实现提供了理论基础.     

Petri网在制造系统建模与仿真中的应用

介绍制造系统的概念以及制造系统建模与仿真的目的和意义,阐述Petri网的内涵,同时引出面向对象的Petri网的定义.依据面向对象的Petri网的理论,给出制造系统的建模过程,最后将统一建模语言(UML)融入到制造系统的建模与仿真中,通过实例进一步阐明了Petri网在制造系统建模与仿真中的应用.