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.     

敏捷制造模式中检验信息的IDEF0模型研究

为在敏捷制造中实现检验的自动化,分析敏捷制造中公差和表面质量的检验信息的需求,提出检验信息模型的功能,设计和开发了检验信息模型的IDEF0(Integration Definition for Function Modelling)模型.     

Geometry-oriented knowledge-based system for preliminary process design of cold-forged parts

This paper presents an integrated architecture of a geometry-oriented knowledge-based process-design system (GEOPDE) for multistage cold forging of solid and hollow parts. It deals with the unit processes of upsetting, forward extrusion, backward extrusion and with combinations of these processes. By using the notion of group technology, the forging processes and forging part geometries are classified. With Prolog as the building tool, the inherited backward chaining reasoning was used for solving the deduction problems. The formation approach, such as “generate and test” and backtracking control strategy, was also employed for generating weighted alternative process plans. Using design rules, empirical formulae and material properties as integrated knowledge, the billet dimensions and the forging sequences are generated automatically once the product dimensions are given by the user. The developed system is a prototype expert system for the preliminary process design of cold-forged products for the forging industry.     

A knowledge-based system for the selection of fluid film journal bearings

This paper describes a knowledge-based system developed for the selection of fluid film journal bearings. The system consists of three major parts which are a knowledge base, an inference engine and a user interface. The system is implemented on HyperCard on a Macintosh computer. The knowledge base is constructed by the method of production rules with weight numbers. A new reasoning mathematical model based on the production rules makes the reasoning much faster. The system operation shows that the system makes intelligent and appropriate bearing selections which are suitable for a user's application.     

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.     

基于多Agent的可重构制造系统故障诊断模型

可重构制造系统对故障诊断有更高的要求。提出了一种基于多Agent的可重构制造系统故障诊断模型,模型为3层结构,从下向上分别为监测Agent层、诊断Agent层和管理Agent层,分析了模型的故障诊断机理,讨论了模型中Agent间的通信与协作。最后例子表明了可重构制造系统重构前后,该模型均能有效完成故障诊断。     

A knowledge-based system for the strategic control level of robots in flexible manufacturing cells

The strategic control level synthesis for robots is related to a hierarchical robot control problem. The main control problem at the strategic control level is to select the model and algorithm to be used by the lower control level to execute the given robot task. Usually there are several lower control level models and algorithms that can be used by the robot control system for every robot task. Strategic control level synthesis depends on the particular robot system application. In a typical application, when the robot system is used in a flexible manufacturing system for manipulating various part types, the robot tasks executed by the robot system depend on the manufacturing processes in the system. If the robot system is applied in another flexible manufacturing system, dedicated to other manufacturing processes, another set of robot tasks might be needed to perform the necessary operations. Therefore, the quantity and the kind of knowledge required in the system for the strategic control level differ from one application to another. Such a fact creates the appropriate conditions for employing some artificial intelligence techniques. This article describes a knowledge-based system approach to the strategic control level synthesis problem.     

The control of a flexible manufacturing system by short-term goal identification

The control of manufacturing systems is characterised by the need to make a compromise between conflicting goals. Traditional research concentrates on steady-state optimisation of single objectives that are not necessarily relevant to decision making in a production environment. The advent of flexible manufacturing systems (FMSs) with automated material handling and limited buffer space highlights the need to provide computationally-efficient solutions to work out scheduling and dispatch problems for real-time applications. The authors have adopted a knowledge-based approach to achieve effective real-time FMS control. In the context of the current system status and planned system activities, short-term goals are identified which lead to appropriate jobdispatch decisions. This approach has been implemented in a prototype control system written in Prolog. To obtain knowledge in this area of scarce expertise, a “define-build-learn” cycle was adopted. First, functional concepts are defined and built into the control system, then the corresponding system characteristics are studied and the results used for further cycles of concept definition and building. This paper describes the development of this operational system.     

基于关键性能指标的流程行业制造执行系统评价体系

面向流程行业,根据制造执行系统的具体特点引人关键性能指标,提出了流程行业制造执行系统的关键性能指标概念定义和评价体系,从流程行业中的生产、质量、库存、维护和能源五大运行部分给出了相应的规范化关键性能指标。通过该评估体系用于实际指导石化行业能源消耗的应用实例,实现了对流程行业综合能耗的有效评估。     

基于多智能体由开放式CNC构筑网络制造系统

在分析先进制造系统特点的基础上,给出了一种基于MAS理论的车间网络控制系统模型。讨论了模型中不同智能体的功能与作用。由开放式数控系统和Intranet组成的DCN系统具有硬件成本低、软件开发费用少、性能好等优点。     

基于Web网络环境分布式制造系统

现代制造技术正向柔性化、敏捷化和智能化发展。在分析基于Web网络环境分布式制造系统的实现原理及制造系统大致结构的基础上,对作为分布式制造系统节点的企业制造系统作了探讨,最后对制造系统特征进行了阐述。     

A consideration of modelling techniques that can be used to evaluate manufacturing strategies

Practising engineers frequently seek to understand what the effects of various manufacturing strategies will be on the performance of their production facilities. In this situation a computer model can help to provide insight and form predictions about future manufacturing system performance. Various types of modelling methods exist and each provide models that have distinct characteristics. This paper presents a review of popular modelling techniques and, based on the results of a structured experimental study, summarises their capabilities to support the evaluation of manufacturing strategies.     

离散制造业可适应制造执行系统的研究与实现

制造执行系统作为现代制造车间的管理控制系统,仍然采用缺少柔性和可配置性的架构,导致其难以适应制造环境和制造过程的变化。针对这个问题,详细分析了制造系统对制造执行系统适应性的需求,研究了可定制数据集成适配器、可配置的工厂模型、可复用的业务组件以及脚本驱动的事件响应机制等关键技术,设计了一种新的可适应性制造执行系统框架。该框架能够在尽量小改动的情况下对制造系统内、外部的变化提供支持。给出了基于该框架开发的一个制造执行系统实现,该系统已被成功应用于不同汽车装配线。     

Workpiece modelling for computer-aided process planning

Different concepts can be applied for representation of workpiece data for CAPP. Instead of waiting for future standards, a practical method is required, which can be used for actual workpieces or those that have been designed in the past by using already existing CAD systems. Therefore, for developing the CAPP system an approach has been chosen which consists of (1) a structure and geometry recognition of the workpiece and (2) an editor for technological data.This paper shows the main characteristics of a workpiece model which can be used for process planning. The results of an analysis of workpieces in industry give an overview of the topological relationships between geometrical elements which is an essential part of workpiece modelling for future design and planning systems. Also, a link between the workpiece model and the CAPP system is presented and briefly discussed.     

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。     

基于Web制造执行系统的设备管理系统研究

论述在Web环境下运用ASP和数据库技术对制造执行系统中的设备进行科学管理,为上层计划管理系统和下层生产控制系统提供实时动态数据,利用有限设备资源,增强企业效益.     

金属结构产品制造业物流管理系统的研究开发

针对金属结构产品制造业物流的特点和需求,提出一种分布式物流应用模式,在此基础上设计和建立了建筑金属结构产品制造业物流管理系统,并且取得一定的应用效果。     

基于多代理机制的车间制造资源调度管理系统的研究

在分析车间制造资源调度特点的基础上,综合运用多代理机制、规则调度和消息通信机制等技术,建立了适应制造企业车间层生产环境的多代理模型结构。重点研究了多代理机制的实现、基于多代理结构下的通信机制和规则调度机制等关键技术,构建了基于客户机／服务器结构车间制造资源的调度管理系统的体系结构,研究了其工作流程和实现方法,并开发了基于多代理的车间制造资源调度管理仿真系统。     

基于多智能体的制造系统生产控制建模研究

为提高制造系统生产控制的性能,建立了基于多智能体系统的混合控制模型.该模型把生产控制系统分为管理智能体层、单元智能体层和执行智能体层.管理智能体层负责调度和协调各单元智能体,并对所有智能体进行管理;单元智能体层中的各单元智能体间通过公用数据库相互协作;执行智能体对制造系统内的硬件负责,它们根据局部的本地资源信息及当前状态,接收发布的任务,并对其求解.同一层次的智能体之间是分布式结构.采用基于多智能体的混合控制模式,提高了制造系统生产控制的实时性和灵活性.通过激光拼焊生产系统中的试验,验证了该模型的有效性.     

Integrated modelling of a time-pressure fluid dispensing system for electronics manufacturing

In electronics manufacturing the time-pressure dispensing system has been widely used to squeeze adhesive fluid in a syringe onto boards or substrates with pressurised air. For accurate control of the fluid volume, it is vital to have a thorough understanding of the whole process. However, the complexity of the process, which includes air-fluid coupling and their nonlinear uncertainties, makes it difficult to obtain an accurate process model. Using the spectral method, an approximate fluid flow model for both the Newtonian and non-Newtonian fluid can be developed. By taking into account nonlinear flow passing through the valve, attenuation and time delay in the pneumatic lines, syringe chamber dynamics and fluid flow dynamics, a simple but effective model is derived to describe the whole dispensing system with reasonable accuracy. Experiments performed thereafter validate the model.