Dimensional metrology interoperability and standardization in manufacturing systems

Dimensional metrology is an important part of any manufacturing system. It consists of distinct components and requires a large, diverse, and interconnected knowledge base. How to pass information seamlessly with minimal cost and minimal data loss between different components of a dimensional metrology system is a major issue that concerns software and hardware vendors, standards developers, and customers. This paper focuses on the four main elements of a dimensional metrology system: product definition, measurement process plan definition, measurement process execution, and analysis and reporting of quality data. The activities and software modules that are involved in these elements are discussed. Key issues that cause interoperability problems are identified. These issues are discussed as they relate to the current situation in dimensional metrology standards development. The STEP (ISO 10303) standards are the product of an international effort to achieve interoperability for manufacturing systems. Extending STEP is an appropriate way to solve the interoperability problem within dimensional metrology systems. Further development of STEP standards is proposed so that Geometric Dimensioning and Tolerancing (GD&T) information already available in STEP can be linked with manufacturing feature information, measurement technology, and measurement results. The proposed STEP data model is an attempt to provide a standard that will support automatic measurement process plan generation for in-process on-machine measurement. Some case studies are under way to test the model.     

一个基于NOVELL网的实时监控平台的设计与实现

通过对ＤＯＳ的多任务环境和网络实时点一点通讯的研究，作者提出并实现了基于ＮＯＶＥＬＬ网的网络实时监控平台，该平台可以方便地由一台工作站实时监控其它工作站，与其它此类系统相比，该系统具有速度快，功能强，使用方便，功能便于扩充等优点，本文就共实现技术作了详细介绍。     

基于STEP的集成化CAD／CAM支撑软件系统

本文介绍了由清华大学ＣＡＤ中心等单位开发的集成化ＣＡＤ／ＣＡＭ支撑软件系统，该系统由六个模块组成，它们是用户接口、交互绘图、产品造型、分析与优化、数控加工和数据库管理该系统采用国际标准ＳＴＥＰ作为产品数据表示和交换的中性机制，使用特征造型、变量化设计方法建立产品信息模型，并使产品信息贯穿于设计、装配、分析、工艺、制造等各个阶段，实现系统的集成。     

基于STEP的CAD知识表达

建立AI系统与CAD系统都能接受的统一的数据表达方式,是解决系统间失配的方法之一,由于越来越多的CAD系统一始支持STEP标准,基于STEP技术的CAD知识表达,就成为建立统一数据模型的有效方法。文章从知识建模、知识编译、物理实现等角度论述了STEP技术在知识表达领域的应用,并在此基础上阐述了KBS与CAD模块间的无缝集成技术。     

CAD数据交换与互操作性的研究

针对目前三维CAD数据的交换状况,分析了基于标准模型和专用接口等两种主要CAD数据交换技术.以STEP标准为例,阐述了基于标准模型的CAD交换技术的架构和实际交换过程中遇到的数据丢失问题.专用接口是点对点的交换,是最原始的解决CAD数据交换的方法,涉及到各个CAD软件的商业利益,在CAD软件众多的情况下,使得CAD数据交换异常复杂.这两种CAD数据交换方法存在一个重大缺陷,即产生的都是"哑"模型,在非原CAD系统中无法对其进行编辑,极大地阻碍了CAD数据的交换.同步建模技术采用概念设计的理念和非历史特征的建模方法,不仅加速了模型设计,也较好地解决了CAD数据的交换问题.     

STEP特征模型及其在集成环境中的应用研究

从STEP特征模型、CAD／CAPP特征建模、STEP工具集的构造、模型映射等角度,论述了STEP技术在CIM领域的应用,在此基础上,阐述了“即插即用”的特征映射及信息集成技术,并讨论了一种在STEP工具集的支持下,以独立于具体系统的方式实现CAD／CAPP特征信息集成的方法。     

The product data model as a pool for CAD-FEA data

CAD-FEA coupling has been the subject of research for a long time. Initially developed with the aim of connecting single applications, requirements due to the interfaces rose along with increasing application of computer-aided methods in product development. The introduction of the termproduct data model in combination with object-oriented technology, allowed progressive work towards the integration of product data. First results have been given in form of a standardized product data model called STEP (ISO 10303) to serve for CAE product data exchange. The authors have had the opportunity to examine the data model introduced by STEP in general and depicting the CAD-FEA connection as well as to implement a prototype STEP interface.The article first presents some fundamentals of product data modeling and related aspects of design and analysis product data, then gives a survey of the case study being done in CAD-FEA coupling with STEP and in conclusion sketches the concept of an object-oriented CAD-FEA integration model to allow for bidirectional and process conform data exchange.     

Integration of cooperative production and distributed design in AEC

Clients and governments are calling for change in the AEC industry. Current initiatives worldwide are seeking to secure a culture of cooperation looking for better performance of this traditionally fragmented industry. The focus has to be on the need to manage the interface between the different project applications as well as the need to improve information flow through seamless integration of electronic data. In this paper a multi-level platform that integrates cooperative production and distributed design in AEC industry is proposed in order to go beyond the identified problems.     

基于STEP的CAD协同工作

该文研究了基于STEP的CAD系统集成方式和传统CAD系统间协同工作方式,并在自主开发的CAD系统GHMDS4.0的体系结构的基础上提出了一种分布式的基于STEP的CAD协同工作的同步协同工作方式,从而为CAD协同工作提供了一种新的思路。最后文章还提出EXPRESS数据库差分方法以减少通讯中的数据量。     

面向应用协议的CAD／CAM集成模式

本文提出以ＳＴＥＰ为核心，直接支持ＣＡＤ后续各应用系统的特征造型方法和ＣＡＤ／ＣＡＭ集成模式，不仅在一般意义上实现基于ＳＴＥＰ的信息集成，而且是对于ＳＴＥＰ利用应用协议实现ＣＡＤ／ＣＡＰＰ／ＣＡＭ信息集成方法的拓展。     

GHCAD：一个产品模型为基础的CAD／CAM集成系统

ＳＴＥＰ是关于产品数据表达和交换的国际标准，如何将ＳＴＥＰ的方法和规范应用于系统开发是解决计算机集成制造系统（ＣＩＭＳ）开发的关键问题之一。集成化ＣＡＤ／ＣＡＭ系统是ＣＩＭＳ的核心，实现将ＣＡＤ的工程设计功能和ＣＡＭ的制造功能的结合。本文介绍一个产品模型为基础的ＣＡＤ／ＣＡＭ集成系统－ＧＨＣＡＤ。系统采用ＳＴＥＰ的数据交换、建模思想，以产品模型为核心，通过ＳＴＥＰ的标准数据接口ＳＤＡＩ实现了系统的集成。     

基于PDM的CAD/CAPP、CAM集成

该文以８６３／ＣＩＭＳ示范工程的实践和开发为依据,对基于产品数据管理（ＰＯＭ）的ＣＡＤ／ＣＡＰＰ、ＣＡＭ集成进行了深入研究。文章首先给出了系统集成的原则,随后提出了ＰＤＭ的框架体系结构和基于ＰＤＭ的集成技术,最后讨论了基于ＳＴＥＰ的产品数据交换和基于ＳＤＡＩ标准数据接口技术。     

STEP/AP203一致性测试软件的实现

STEP一致性测试保证实施过程中产品数据的一致性和完整性。文章通过对STEP一致性测试方法的研究,结合STEP/AP203一致性测试软件的实现,讨论了测试系统的结构、测试过程和内容,重点分析了对交换结构的规则与约束的检查,最后介绍了软件系统开发过程中的相关技术问题。     

Repairing CAD model errors based on the design history

For users of CAD data, few things are as frustrating as receiving unusable, poor quality data. Users often waste time fixing or rebuilding such data from scratch on the basis of paper drawings. While previous studies use the boundary representation (B-Rep) of CAD models, we propose an approach to repairing CAD model errors that is based on the design history. CAD model errors can be corrected by an interdependency analysis of the feature commands or of the parametric data of each feature command, as well as by a reconstruction of the feature commands through rule-based reasoning of an expert system. Unlike other correction methods based on B-Rep models, our method repairs parametric feature models without translating them to a B-Rep shape, and it also preserves parametric information.     

基于软件总线CAD软件体系结构研究

针对几种传统CAD软件体系结构模型存在的问题,在分析了软件总线的基本特点之后,将软件总线的概念引人到CAD软件体系结构中,提出了一种基于软件总线的CAD系统架构,并从系统设计和开发的角度,详细分析了各个组成部分及其功能．结合KerenCAD软件开发过程中的实际情况,利用KerenCAD中的视图、文档和主框架等基本组成元素进一步阐述了这种新型CAD软件的体系结构．     

A set of standard modeling commands for the history-based parametric approach

The current version of STEP standard cannot exchange the parametric information of CAD models. Only pure boundary representations that cannot be parametrically edited are transferable [Geometric Modeling: Theory and Practice (1997)]. There are two approaches for the exchange of design intents such as parameters, features, and constraints. The first is an explicit approach based on constraints between pre-defined parameters and features. The second is a procedural approach based on the sequence of operations issued to construct the models. The authors have previously proposed a macro-parametric approach [International Journal of CAD/CAM 2 (2002) 23], which is a variation of the procedural approach. In this approach, CAD models can be exchanged in the form of macro files, which include the history of modeling commands. To exchange CAD models using the macro-parametric approach, a set of standard modeling commands should be defined. This paper introduces a set of standard commands and explains the process of developing the set.     

利用PDES／STEP实现CAD／CAM信息集成

本文介绍了新一代基于产品数据的数据交换标准ＰＤＥＳ／ＳＴＥＰ的结构和特点，并提出了将基于特征的造型系统所建立的产品信息模型运用ＰＤＥＳ／ＳＴＥＰ来表示，从而实现ＣＡＤ／ＣＡＭ信息集成系统中数据交换和共享的方法。     

STEP信息集成软件工具的设计和实现

ＳＴＥＰ是国际标准化组织ＩＳＯ正在组织开发的应用于计算机集成制造系统（ＣＩＭＳ）信息集成的产品数据表达与交换标准，ＳＴＥＰ不仅是一种规范，更是一种信息集成技术，本文以ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成为背景，提出了ＳＴＥＰ信息集成支持工具ＥｘＴｒａ的设计和实现技术，该软件工具已成功且有效地应用于ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统集成中。     

A STEP-BASED CAD/CAPP INTEGRATION

ＡＳＴＥＰ－ＢＡＳＥＤＣＡＤＩＣＡＰＰＩＮＴＥＧＲＡＴＩＯＮＺｈｅｎｇＬｉａｎｙｕ；ＤｕＰｅｉＡＳＴＥＰ－ＢＡＳＥＤＣＡＤＩＣＡＰＰＩＮＴＥＧＲＡＴＩＯＮ￥ＺｈｅｎｇＬｉａｎｙｕ；ＤｕＰｅｉＡｂｓｔｒａｃｔＴｈｅｉｎｆｏｒｍａｔｉｏｎｉｎｔｅｇｒａｔ...