Complexity of cellular manufacturing systems based on entropy models

Even structurally simple manufacturing systems can be operationally complex. This operational complexity can be colloquially defined as the uncertainty associated with managing the dynamic variations, in time or quantity, across information and material flows at the manufacturing systems interface. This paper proposes a means of measuring the information demands placed on cellular manufacturing systems, as a result of this uncertainty. A utility function for complexity is proposed according to the relationships between the complexity and utility in a manufacturing system and the underlying trend that the system becomes more and more complex in an everchanging environment is analyzed. This paper mathematically models the static entropy and the dynamic entropy of cellular manufacturing systems from an information-theoretic perspective. A unique feature of this measure is that it captures, in relative terms, the expected amount of information required to describe the state of the system. The measure provides flexibility in the scope and detail of analysis. Finally, an example is used to demonstrate the validity of the proposed methodology.     

支撑制造系统有效运作的制造信息差的性质和作用研究

制造信息差(DMI)是一种二次生成的信息，是制造系统中最普通、最常见的信息现象之一。从支持制造系统有效运作的角度阐述了DMI的性质和作用。列举了DMI的主要性质，给出了数值型、确定型和概率型制造信息的表述及其DMI的求算方法。指出制造系统组元间存在DMI是组元间存在合理的制造信息流的必要信息条件，它决定了合理信息流的方向和内容。阐述了动态存在于制造系统中的DMI是保证制造系统有效运作的必要信息条件之一。讨论了制造信息的三种递减性，列举了主要的抗制造信息递减的措施。     

Product and manufacturing capability modelling in an integrated CAD/process planning environment

Computer-aided process planning (CAPP) is one of the key components in computer integrated manufacturing (CIM) environment. Fully automatic CAPP systems require information transfer between CAD/CAM systems to be mutual, dynamic, concurrent, automatic and efficient. The difficulty in achieving this is the management of the vast amount of heterogeneous data, knowledge and complicated inference processes encountered in developing automatic planning systems. The objective of the reported research is to develop a framework for modelling and managing engineering product and manufacturing capability information in an integrated feature-based CAD/knowledge-based process planning environment. The feature-based design system is developed with a commercial boundary representation (Brep) solid modeller with additional feature-modelling functions. The process planning system is developed using a knowledge-based system, which is fully integrated with the design system through an information mapping mechanism. Process planning decisions are made by searching for a match between the product requirements and the process capability of available manufacturing systems. This is achieved by invoking the rules coded in an inferencing mechanism (an inference engine). Both the underlying methodologies and the implementation aspects will be addressed in this paper.     

Object-oriented methods for manufacturing information systems

Object-oriented programming (OOP) is now widely used in application software development. OOP has advantages connected with handling complexity, reusability, extendability, modularity and data abstraction, enabling it to handle modern programming requirements more effectively than conventional programming methods. Successful advanced manufacturing systems demand increasing complexity, flexibility and integration between computer applications. An object-oriented approach is particularly promising for the design and development of manufacturing information systems. This paper outlines the concepts of object-oriented methods, and describes an object-oriented application development methodology for manufacturing information systems. A CASE (Computer-Aided Software Engineering) tool is used for system modelling and for direct source-code generation. A case study describing the development of a quality management information system is presented, which was implemented using a C++ development environment. Although the research described here is concerned with quality management information systems, the proposed design methodology is applicable to other areas of manufacturing, and conclusions are drawn concerning the uses of OOP in manufacturing information systems generally.     

基于MAS的制造系统监控技术研究

为了提高制造系统的敏捷性和可控性,研究了基于MAS的制造系统控制结构,提出一种具有监控功能的制造资源Agent模型及其信息采集模块实时信息处理的标准化流程。对制造资源Agent的功能和结构进行了详细分析,并论述了实现过程。通过该模型实现了对现场信息的采集、匹配、融合和传输,从而保证制造系统现场信息的及时反馈。最后通过建立实验系统证明了该模型的可行性。     

Modelling CIM systems part I: methodologies IDEFO,an effective tool for implementing the checkland methodology

A research programme is being undertaken with a major UK manufacturing company to develop the information systems environment on which the computer integration of the whole of the manufacturing system depends. Inevitably this programme has led to explorations of fundamental systems ideas and of the methodologies that are now emerging to support such work.In this paper two such methodologies are contrasted. In subsequent papers applications of these technologies will be demonstrated and conceptual models for the information systems environment in manufacturing engineering presented.     

A formal model for incorporating shop floor controls into plant information systems

The high cost and long development cycle of shop floor controls (SFC) have prevented many small, medium, and even large-size manufacturers from deploying plant-wide, real-time information systems. In order to stay competitive in a make-to-order business model, such systems are essential. In addressing the obstacles to such systems, this article proposes a formal method that ensures that a built SFC can be applicable to a plant-wide, real- time information system. By taking advantage of both the linear growth of the complexity function in a structured adaptive supervisory control model, and the real-time responses of a virtual production line based e-Manufacturing system, a formal method for creating an integration-ready structured adaptive supervisory control model (iSASC) for a discrete manufacturing system is introduced. An iSASC-based SFC prototype system was successfully tested and evaluated in an industrial site.     

Integrated Modeling Framework for Manufacturing Systems: A Unified Representation of the Physical Process and Information System

The task of process modeling in a manufacturing environment centers around controlling and improving the flow of materials. This flow comprises a complicated web of control and physical systems. Despite a variety of manufacturing system modeling approaches, more rigorous process modeling is required. This paper presents an integrated modeling framework for manufacturing systems (IMF-M). Conceptual modeling of physical materials flow supported by a graphical representation facilitates improvement of operations in manufacturing environments. A declarative and executable representation of control information systems helps to improve information management by managing a variety of information models with improved readability and reusability. A unified representation of the physical process and information system provides a common modeling milieu in which efforts can be coordinated among several groups working in the different domains of scheduling, shop floor and logistics control, and information system. Since the framework helps adapt to the changes of the physical process and information system affecting each other in a consistent manner, the modeling output enhances integration of the manufacturing system.     

Information requirements analysis for holonic manufacturing systems in a virtual environment

The design and development of holonic manufacturing systems requires careful, and sometimes risky, decision making to ensure that they will successfully satisfy the demands of an ever-changing market. In this paper, the authors propose a methodology for a holonic manufacturing systems requirement analysis that is based on a virtual reality approach and aimed at assisting designers of such systems along the entire systems design and development process. Exploiting virtual reality helps the user collect valid information quickly and in a correct form by putting the user and the information support elements in direct relation with the operation of the system in a more realistic environment. A prototype software system tool is designed to realise the features outlined in each phase of the methodology. A virtual manufacturing environment for matching the physical and the information model domains is utilised to delineate the information system requirements of holonic manufacturing systems implementation. A set of rules and a knowledge base is appended to the virtual environment to remove any inconsistency that could arise between the material and the information flows during the requirement analysis.     

Advanced RFID application for a mixed-product assembly line

Due to its scale, complexity, and uncertainty of the processes, the management and control of automotive manufacturing systems have been very challenging. With the recent application of new technologies such as radio frequency identification (RFID) to manufacturing process, real-time information has become available in manufacturing systems through IT infrastructures. It is expected that RFID-based real-time information will increase timeliness and efficiency in decision making and drastically reduce uncertainty. That, in turn, will enhance both productivity and quality. This paper presents an advanced RFID application for automotive assembly processes, specifically, dynamic material dispatching (e.g., auto assembly parts). The application is uniquely advanced in that it integrates RFID technology with a real-time decision support system to ensure the accurate and efficient delivery of auto parts to mixed-product assembly lines. In this application, we have described the problem as a mixed-integer programming model, proposed a heuristic algorithm that incorporates the available RFID information, and assessed the value of RFID through a scenario-based analysis. We hope this paper may help contribute to a virtuous cycle of RFID innovation and applications in the manufacturing sector.     

A mechanism for the integration of TQM and MRPII

This paper presents a quality management system based on Manufacturing Resource Planning (MRPII). A real-time monitoring system is used to acquire the information necessary for MRPII to drive quality management over this framework. Firstly, the concept of Total Quality Management (TQM) is overlaid on the structure of MRPII. Secondly, quality management activities in manufacturing systems are used to shape the manufacturing database concept and information models of various manufacturing activities. Finally, a complete dynamic system model setting out the architecture of a proactive resource planning environment that encapsulates quality management is derived.     

基于状态熵的制造系统结构复杂性建模与评价

针对现有结构复杂性建模方法存在的不足,在考虑中间缓冲区状态对制造系统状态影响的基础上,提出一种基于通用发生函数法和信息熵理论的非串行制造系统结构复杂性建模与评价方法,从系统角度对制造系统的复杂性进行测度。通过建立中间缓冲区的状态转移方程,定义缓冲区的状态,分析中间缓冲区状态对非串行制造系统各工位加工设备状态的影响,将原制造系统转化为等效系统;利用通用发生函数法描述各等效加工设备的性能及其发生概率,并将制造系统分解成若干并联和串联子系统,引入并联和串联复合算子求解整个系统的发生函数,得到系统的状态空间及其对应的概率空间;从系统角度出发,利用信息论中的信息熵模型建立非串行制造系统的结构复杂性模型。以某车间的非串行缸盖柔性加工线为例,验证该模型与评价方法的有效性。     

A system for the design and manufacture of feature-based parts through the Internet

The Internet has enabled the development of applications for supporting the design and manufacturing of industrial parts and products. Some actions have been performed by some research groups in different parts of the world aiming at conceiving product modeling systems based on the technology of features to allow information sharing, both for the activities related to product development and for manufacturing. This paper describes the implementation of the WebMachining system () developed in a context of e-Mfg and concurrent engineering, aimed at integrating CAD/CAPP/CAM for the remote manufacturing of feature-based cylindrical parts with symmetrical and asymmetrical features through the Internet, using an approach based on multi-agent systems. The information referring to the features is manipulated through a relational database management system. The graphic user interface (GUI) is implemented in Java and HTML. In this GUI, the user inputs the information on the design features that compose the part. Then these data are sent to the server. Since the part is cylindrical, the user models the part in two dimensions, and it can be visualized as three-dimensional through VRML. A database was implemented that stores the information on the product modeled by features, containing information associated with the form features, material features, tolerance features and technological features. These combined pieces of information allow the mapping of design features into machining features, which is fundamental for process planning. The database information is described in this article through the IDEF1X information model.     

基于MES系统的智能制造切削加工系统架构设计

随着信息技术和新的制造工艺的发展,智能制造技术成为传统制造企业产业升级的关键技术。MES系统在智能制造系统中的作用是贯穿始终的,且与PLC通信采取应答机制。该文设计了智能制造切削加工系统的总体架构,并结合MES软件将数控车床、加工中心、PLC、机器人、RFID及立体仓库等信息系统进行有效结合,完成了生产过程的智能化管理,对同类企业进行智能制造技术的应用提供了可借鉴的经验。该系统可降低没有附加价值的活动对工厂营运的影响,进而改善企业制程,提高生产效益。     

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.     

RFID-enhanced multi-agent based control for a machining system

Recent research on highly distributed control methods for complex systems have produced a series of philosophies based on negotiation, that bring together process engineering with computer science. Among these control philosophies, the ones based on multi-agent systems (MAS) have become especially relevant. Furthermore, among a number of MAS implementations, those that use different types of agents at different conceptual/managerial levels are commonly applied. However, these MAS models have the drawback of an excessive dependence on up-to-date information about the products and other elements that move within the system. A new technology has come out that can help solve this problem: radio-frequency identification enhanced information management systems (RFID-IMS). One of these is Auto-ID/EPCglobal technology. This paper shows how a MAS model can be used for controlling a machining system incorporating RFID-IMS technology. The resulting system becomes an RFID-enhanced intelligent manufacturing system (RFID-IMS II).     

e-制造系统的制造资源动态配置过程研究

传统制造资源动态配置没有涉及制造系统、制造单元和设备之间制造过程信息的重组模型,据此,在拓展传统制造资源动态配置模型的基础上,结合模糊聚类理论,研究了e制造环境下制造任务在一定批量和多工艺方案情形下的单元化配置模型,以及基于此配置结果的制造系统、动态制造单元、设备间的信息重组模型与制造过程信息跟踪方法,为“柔性制造”、“数宁化精确生产”奠定了基础,并对开发的原型系统进行验证。     

Intranet构架下炼钢制造业集成化生产管理系统

分析了某炼钢厂的生产管理系统现状。针对该炼钢厂，提出了Intranet构架下的集成化生产管理系统。设计了该系统的信息集成平台、网络体系结构和功能。通过在该厂实施该系统，保证了信息资源的共享，有效地提高了管理效率和决策水平。     

基于信息熵的制造系统复杂性测度及其在调度中的应用

制造系统的复杂性是指制造系统难以被理解、描述、预测和控制的状态。从信息论角度指出制造系统的复杂度是描述制造系统的状态所预期需要的信息量。将制造系统的复杂性描述为静态和动态两种形式:静态复杂性是描述制造系统在静止状态下各制造资源根据其调度方案所预期拥有的状态所需要的信息量,动态复杂性则指描述制造系统在运行过程中各资源的实际状态所需要的信息量。应用信息论中的信息熵理论研究制造系统的复杂性测度问题,分别建立了基于信息熵的静态和动态复杂性测度模型。将上述复杂性理论应用于调度研究,提出最大可行调度时限和调度依附度两个评价调度有效性的量化指标,为调度有效性的分析、评价及改善提供了重要工具。实例研究表明所提理论和方法的有效性。     

现代制造系统与生物型产品信息模型

探讨现代制造系统的两个重要的发展趋势；集中化和分散化的统一及自稳定机制和突变机制的统一，在此基础上提出生物型制造系统与生物型产品信息模型概念，研究表明，将现代制造系统和产品信息模型与生物系统联系起来进行研究；有助于更深刻地理解现代制造系统和产品信息模型本质。