Object-based knowledge bases in automatic manufacturing environments

A manufacturing system is a very complex network of physical activities, decision making and information flows. Hence the complexity of the design and the integration of such a system increases with increases in the degree of automation. In this paper the authors propose to use the framework of an object-oriented knowledge base as the basis to, organise the knowledge in an automatic manufacturing environment. Such systems can provide significant advantages in terms of knowledge management, integrity control, object abstraction, design abstraction, and very high level programming. The power of this framework is illustrated in detail in the context of process planning, which is one of the major components of an automatic manufacturing environment. This research is supported by the National Science Foundation under grant number CDR-85-00022.     

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.     

Assessing the structural complexity of manufacturing systems configurations

Modern manufacturing systems are increasingly required to be flexible and adaptable to changing market demands, which adds to their structural and operational complexity. One of the major challenges at the early design stages is to select a manufacturing system configuration that both satisfies the production functional requirements and is easy to operate and manage. A new metric for assessing the structural complexity of manufacturing system configurations is presented in this paper. The proposed complexity metric incorporates the quantity of information using an entropy approach. It accounts for the complexity inherent in the various modules in the manufacturing system through the use of an index derived from a newly developed manufacturing systems classification code. The code captures the effect of various component types and technologies used in a manufacturing system on the system’s structural complexity. The presented metric would be helpful in selecting the least complex manufacturing system configuration that meets the requirements. An engine cylinder head production system is used to illustrate the application of the proposed methodology in comparing feasible but different manufacturing system configurations capable of producing the cylinder head based on their structurally inherent complexity.     

Reverse simulation for collaborative commerce: A study of integrating object-oriented database technology with object-oriented simulator

Collaborative commerce has been used for communication, design, planning, information sharing, and information discovery in business-to-business (B2B) applications. The collaboration between buyers and sellers enhances product quality and customer satisfaction. However, most effort currently focuses on information sharing with customers and suppliers instead of joint product development or manufacturing. Moreover, traditional analytical methods have limited capability in solving problems. This study presents a framework for doing reverse simulation, where designers can reuse past experiments and change system parameters in manufacturing system for collaborative commerce. The framework integrates the object-oriented simulator and the object-oriented database. In this framework, the object-oriented database records the whole experiment scenarios and allows multiple planners with different expertise to involve concurrently and collaboratively. Then, simulations of advanced planning and scheduling in a product manufacturing environment that involves several planners working collaboratively are used for demonstration.     

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。     

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.     

An integrated object-oriented approach for design and analysis of an agile manufacturing control system

The agile manufacturing paradigm has emerged as an important concept in the development of manufacturing systems. The control software, developed based on the object-oriented technology, leads to reusability, reconfigurability, and scalability; and the agility of a manufacturing control system can be achieved. In this research, an efficient and systematic methodology for developing an object-oriented agile manufacturing control system is proposed. The proposed development process is divided into four stages: functional analysis, static structural analysis, behavior analysis and verification, and system implementation. The Integration Definition for Function Modeling (IDEF0), Object-Oriented Petri Net (OPN), and Unified Modeling Language (UML) are integrated into the corresponding stages based on their characteristics. In order to develop the system rapidly and efficiently, the transformation rules between the IDEF0 and OPN, and between the OPN and sequence diagram are conducted. In addition, the attributes and operations for each object are also defined directly from the OPN model. The result of the integrated IDEF0/OPN/UML systematically leads to object-oriented control software design for manufacturing systems. Finally, an assembly and packaging system is given to illustrate how the integrated object-oriented approach is implemented for developing the manufacturing control system.     

An Infrastructure for Integrated Automation System Implementation

Evolution of advanced manufacturing technologies and the new manufacturing paradigm has enriched the computer integrated manufacturing (CIM) methodology. The new advances have put more demands for CIM integration technology and associated supporting tools. One of these demands is to provide CIM systems with better software architecture, more flexible integration mechanisms, and powerful support platforms. In this paper, we present an integrating infrastructure for CIM implementation in manufacturing enterprises to form an integrated automation system. A research prototype of an integrating infrastructure has been developed for the development, integration, and operation of integrated CIM system. It is based on the client/server structure and employs object-oriented and agent technology. System openness, scalability, and maintenance are ensured by conforming to international standards and by using effective system design software and management tools.     

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.     

Establishment of the model for flexible manufacturing system based on CORBA and IDEF0

Integrated Integration Definition Language (IDEF₀) is an activity-based modelling technique for modelling the activities and information flows in a manufacturing system. Based on the entities involved in the system and the interactions abstracted from IDEF₀ approach, an object-oriented method based on Common Object Request Broker Architecture (CORBA) is developed in a hierarchically distributed control system. The application of CORBA as a middleware for the development of distributed object systems simplifies the implementation of clients and servers at different locations. The data and general methods in distributed controllers are integrated into servers; the controller is able to communicate with the server through the communication mechanism of CORBA. A prototype system which is constructed to validate the flexible manufacturing system is presented in details.     

Informational model of digital manufacturing (ISA-95 standard)

The development of an information model of digital manufacturing is considered. The goal of the model is maximum integration of the management systems for enterprise resources (ERP) and the product life cycle (PLM) and for operational management (MES), by expanded application of the provisions of the ISA-95 standard. A methodology is proposed for creating digital doubles of real production processes by the development of the Herbarium integrated engineering software platform (Foundation for Advanced Studies).     

A WWW-Based Information Management System for Rapid and Integrated Mould Product Development

As efficient management of product information that covers the whole life cycle is critical to the enhancement of corporate competitiveness. This paper explores the design and development of a World Wide Web (WWW) based product development information management system for a cross-nation manufacturing corporation that is headed by a holding company in Christchurch, New Zealand. Since product data are often managed in a distributed computing environment, common object request broker architecture (CORBA) is employed to ensure the interoperability among distributed information objects. A STEP-based information framework is proposed to preserve the openness of the system. This WWW-based information management system is discussed in this paper, which includes two major components: 1. WWW-based product design and development distributed object-oriented databases and knowledge bases. 2. A WWW-based integrated system platform. Several sub-models are introduced, which include an object-oriented database structure, a WWW-based information management system, a WWW database tool, an information access tool, the incremental process-planning method, a cost-optimisation model and an integrated software platform for the integration of CAD, CAPP, CAM, and a WWW-based information management system.     

Development of the supply chain oriented quality assurance system for aerospace manufacturing SMEs and its implementation perspectives

Aerospace manufacturing SMEs are continuously facing the challenge on managing their supply chain and complying with the aerospace manufacturing quality standard requirement due to their lack of resources and the nature of business. In this paper, the ERP system based approach is presented to quality control and assurance work in light of seamless integration of in-process production data and information internally and therefore managing suppliers more effectively and efficiently. The Aerospace Manufacturing Quality Assurance Standard (BS/EN9100) is one of the most recognised and essential protocols for developing the industry-operated-and-driven quality assurance systems. The research investigates using the ERP based system as an enabler to implement BS/EN9100 quality management system at manufacturing SMEs and the associated implementation and application perspectives. An application case study on a manufacturing SME is presented by using the SAP based implementation, which helps further evaluate and validate the approach and application system development.     

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.     

Manufacturing process modelling using process specification language

The manufacturing process is one of the important processes in a product??s life cycle. The sharing of manufacturing process information among different functional application systems, such as process planning, manufacturing simulation, manufacturing execution and project management, has become difficult to implement due to the growing complexity of the manufacturing information of product, process, resource and plant. A unified representation of manufacturing process information for all applications can enable convenient integration between different application systems. The development of manufacturing-related ontology and the Process Specification Language (PSL) has provided a formal definition and structure of semantic concepts for the capture and the exchange of manufacturing information. This paper presents a manufacturing process information modelling method which builds a standard, complete and exact definition of manufacturing process data by applying current PSL specifications. New extensions of the concepts of the manufacturing process and the types of relationship for describing activities, materials and resources in a process are identified and developed. The completeness and adaptability of activity relation of the proposed manufacturing process information representation is verified using mathematical induction under a variety of complex manufacturing process situations. The ability of the modelling method in expressing complex process information is demonstrated by a machining process example.     

面向对象的CAD／CAM集成技术的研究

将面向对象方法应用于ＣＡＤ／ＣＡＭ集成的研究，提出面向对象的ＣＡＤ／ＣＡＭ集成的思想和方法；利用面向对象方法建立够集成产品设计和制造信息的产品定义模型－面向对象的产品定义模型，集成表达零件的设计，工艺规划，数控编程等活动所需信息，在此基础上开发ＣＡＤ／ＣＡＭ集成系统。介绍利用该思想方法所开发的回转类零件ＣＡＤ／ＣＡＭ集成系统。     

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.     

Modeling of large-scale complex re-entrant manufacturing systems by extended object-oriented Petri nets

In this paper we propose an extended object-oriented Petri nets (EOPNs) for effective modeling of large-scale complex re-entrant manufacturing systems (ReMSs). To cope with their complexity because of the re-entrant process route and the mixed production mode, a special type of transition called a main-bus gate (MBG) is introduced, which can cause products to undergo every re-entrant manufacturing stage. A hierarchical approach is also applied to cope with the complexity. As a typical large-scale complex ReMS, the semiconductor wafer fabrication system (SWFS) is taken as an example for demonstrating the proposed EOPNs. A case study is provided to show the modelling procedures, and the resulting model validates that the EOPNs can cope well with the modelling complexity of large-scale complex ReMSs.     

复杂电子装备制造数据建模与集成应用研究

目前,对复杂电子装备制造过程中多层级、多节点、信息庞杂的制造物料清单(Manufacturing Bill of Material,MBOM)和实装物料清单(Built Bill of Material,BBOM)的数据建模及其在系统集成中的应用尚无深入研究.文中深入研究了复杂电子装备的MBOM、BBOM模型及映射过程...     

面向制造信息管理的射频识别技术应用研究

探讨了射频识别技术在制造信息管理方面新的应用，介绍了制造信息管理系统的结构框架以及实验平台开发的方法。通过实例，阐述了基于射频识别的制造信息管理系统开发过程，从而表明该研究在制造信息化方面的应用意义。