支持协同工作的工程CAD/CAM系统研究

首先介绍了计算机支持协同工作的概念和原理，以及CAD／CAM系统发展趋势；然后对支持协同设计的工程CAD／CAM系统的支撑环境、系统协同模型、实时协同设计过程进行了相应的分析与说明；最后设计出一个支持协同设计的工程CAD／CAM系统模型，并在一个纺织面料CAD系统中得以应用。     

异构CAD协同设计系统的集成与实现

随着CAD软件的逐步普及,设计工作效率得到了很大的提高,但这些软件没有形成一个完整的系统,信息共享程度低,信息传递速度慢,无法实时监控项目,应用系统集成效率不高,而且不同设计师可能所擅长的CAD软件不一样.因此,文章提出集成多种CAD软件分组的系统协同设计系统的架构模型,介绍了系统构建方法、体系结构框架与关键技术,并着重阐述了异构CAD协同设计环境下采用ActiveX控件实现客户端与服务器之间的数据交互.     

基于中间件的分布式协同CAD应用研究

提出了一种基于中间件的分布式协同CAD应用框架。采用中间件来封装传统的单机CAD系统。探讨了中间件的里封装与表封装的构造与功能。通过该应用框架,可以集成多个单机CAD系统,使其成为分布式协同CAD应用环境。     

基于共享工作空间的协同系统关键技术的研究

协同设计是当前计算机支持下的协同工作(CSCW)研究领域的前沿课题之一,文章针对构建协同CAD设计应用环境,提出了一种基于共享工作空间的多任务、多角色协作模型(PBCEs),建立了相应的访问控制和并发控制机制,并在一协同设计系统CoopCAD系统中得到了运用,较好地满足协作应用系统的要求。     

基于CSCW的CAD系统协作支持技术与支持工具的研究

计算机支持的协同工作（CSCW）给CAD技术带来重大发展，但仍然存在许多问题。其中之一是缺乏将协作性能同应用功能有机结合的方法。文中在分析的现有协作支持技术，工具和系统不足的基础上，提出了用协作支持工具软件CoCADToolAgent改造商品化CAD系统来开发CSCD系统的新思路和总体技术路线，给出了通讯支持，协议，一致性维护和并发控制，协同感知，任务和脚色机制的有效的实现方法，作为本方法的一个应用实例，成功地将传统的人机交互式CAD系统AutoCAD转变为网络环境下支持人人交互的CSCD原型系统，作为专用协作支持工具，CoCADToolAgent比NetMeeting之类的通用协作支持工具具有更好的协作性能，该方法可推广到三维CAD系统。     

基于角色的群体感知模型实现机制

群体感知功能是计算机支持协同工作系统和群件系统必须支持的基本功能。文章分析了群体感知研究工作的现状,介绍了一种基于角色的群体感知模型RAM,给出了该模型实现的总体结构,并从角色任务树的组成和构造算法、角色管理框架和协议、感知模型引擎和系统调用API等几方面讨论了实现机制。最后给出了基于RAM的协同编著系统应用框架,讨论了在下一步研究中仍需解决的若干问题。     

以网络为中心的协同特征造型

在网络化同步协同设计环境中,如何实现CAD系统之间的实时数据交换和模型同步,成为协同几何造型的关键问题。文中提出了一种新的复制式协同特征造型方法,该方法将现有的特征造型技术与分布计算、网络通信技术相结合,通过简单的造型消息交换来实现增量式协同造型,可以较好地满足几何模型实时同步的需要,而且也部分地解决了异构CAD软件之间的数据交换问题;并详细地介绍了协同造型通信协议、对象引用机制、以及分布式协同造型系统。     

基于XML和Automation APIs的CAD模型集成与交换研究

异构数据源(例如不同CAD系统之间)的交换和共享是虚拟产品开发中信息集成的核心。一般是采用基于设计历史参数化建模方法进行模型交换,但特征和几何信息的交换导致了转换器规模变大;另外转换器采用过程模型作为中性文件,需要几何建模内核生成内部显式模型。为了解决该问题,提出了一种称之为MidCAD的共享集成平台,该平台将转换器和中性文件分开,这样商业CAD系统的转换器只和MidCAD进行交互。采用Microsoft开发的Automation APIs实现MidCAD的交互通信。转换器利用MidCAD的Automation APIs将源CAD模型转换为XML宏文件,或将XML宏文件转换为目标CAD系统的模型。对MidCAD集成平台进行了验证。     

基于CSCW的商用CAD系统框架结构

在充分研究现有商业CAD体系结构的基础上提出了一种新的基于CSCW的商用CAD系统框架结构.该系统框架在原有DoctorCAD系统的基础上全面采用JAVA技术,并增加了外部用户接口和协同控制模块,实现了异地协同设计.最后具体讨论了关于本系统的一些关键性技术并给出了一个系统的应用实例.通过应用实例表明,该系统框架很好地满足了现代商业设计的要求.     

协作支持工具CoCADTool Agent中的远程指针协同感知技术

文中以一个基于CSCW的CAD系统协作支持工具CoCADToolAgent的研究和开发为背景 ,介绍CoCADToolAgent中的远程指针协同感知技术 ,包括共享光标和动态多光标的实现方法。     

异构CAD系统语义信息交换方法研究

传输完整的CAD模型语义信息是协同设计有效进行的关键,提出了一种异构CAD系统语义信息交换方法,该方法通过构建语义转换器实现了常规文件、压缩文件和中性文件三种模型文件的数据转换和翻译,并给出了判定特征相似性的方法,实现了源CAD系统和目标CAD系统的语义互操作,保证了语义传输的完整性和高效性。构建了一个协同资源共享平台,在该平台下实现了Pro/E系统和UG系统之间的语义数据交换,协同传输效率提高了近30%。     

The multi-user computer-aided design collaborative learning framework

New developments to computer-aided design (CAD) software transform a once solitary modelling task into a collaborative one. The emerging multi-user CAD (MUCAD) systems allow virtual, real-time collaboration, with the potential to expand the learning outcomes and teaching methods of CAD. This paper proposes a MUCAD collaborative learning framework (MUCAD-CLF) to interpret backend analytic data from commercially available MUCAD software. The framework builds on several existing metrics from the literature and introduces newly developed methods to classify CAD actions collected from users’ analytic data. The framework contains two different classification approaches of user actions, categorizing actions by action type (e.g., creating, revising, viewing) and by design space (e.g., constructive, organizing), for comparative analysis. Next, the analytical framework is applied via a collaborative design challenge, corresponding to over 20,000 actions collected from 31 participants. Illustrative analyses utilizing the MUCAD-CLF are presented to demonstrate the resulting insight. Differences in CAD behaviour, indicating differences in learning, are observed between teams made up entirely of novices, entirely of experienced users, or a mix. In pairs of experts and novices, we see both a perceived high-satisfaction apprenticeship experience for the novices and preliminary evidence of an increase in expert design behaviours for the novices. The proposed framework is critical for MUCAD systems to make the most of the educational possibility of combining technical skill-building with team collaboration. Preliminary evidence collected in a fully-virtual design learning activity, and analyzed using the proposed MUCAD-CLF, shows that novice students gain advanced CAD design knowledge when collaborating with experienced teammates. With the user data captured by modern MUCAD software and the MUCAD-CLF presented herein, instructors and researchers can more efficiently assess and visualize students’ performance over the design learning process.     

Development of a collaborative CAD/CAM system

This paper presents the development of a collaborative CAD/CAM system (COCADCAM). COCADCAM extends an existing single-location CAD/CAM system to a multi-location CAD/CAM application so that two geographically dispersed CAD/CAM users can work together on a three-dimensional CAD-geometry coediting and CAD-related tasks collaboratively and dynamically. COCADCAM dynamically supports CAD data communication that are not available in traditional single-location CAD/CAM. The dynamic data communication is achieved through the development of networking algorithms and CAD/CAM functions in this paper. The networking algorithms based on UNIX Interprocess Communication (IPC), the Network File System (NFS), and a connection-oriented client and server model under the Transmission Control Protocol/Internet Protocol (TCP/IP) suite. The CAD/CAM functions included surface modelling, simulation of a milling toolpath, and post-processing of an NC program following collaborative CAD-geometry coediting, which are directly or indirectly supported by the Application Programming Interface (API) of the CAD/CAM software. The networking algorithms and CAD/CAM functions together can facilitate an environment for CAD-geometry coediting and related tasks such as design, analysis and manufacture. COCADCAM has been successfully implemented through local area network (LAN) and the Internet; a remote machining cell is also linked so that the generated NC program based on a coedited free-form surface can be used for the physical machining operation. The algorithm proposed by COCADCAM can be referenced for the extension of other single-location CAD/CAM systems to multi-location applications.     

基于STEP的三维CAD和PDM系统集成方法研究

研究了基于STEP标准的产品信息模型、CAD数据交换接口、产品数据交换接口,提出了基于STEP中性机制和产品信息模型的三维CAD和PDM系统集成框架,该框架有助于实现广义CAD功能CAD/CAE/CAPP/CAM/CAQ/PDM/ERP之间的系统集成,异地、异构系统在企业间的集成,能够为企业设计和管理信息化提供一体化解决方案.     

异构CAD系统协同构架研究*

针对异构CAD系统间上层操作指令和底层数据结构存在的差异性,在细胞元语义特征造型技术的基础上,提出了一种全新的支持异构CAD系统间同步协同设计的体系结构,并通过一种优先调度机制有效地解决了异构CAD系统间的“写冲突”问题,提高了实时响应性。该思想初步应用在HUSTCAIDS与AutoCAD间的异构协同设计中,证明了其可行性。     

甘蔗收获机械可视化虚拟设计平台的研究开发

介绍了甘蔗收获机械可视化虚拟集成设计平台研究开发的基本思路。该平台的构建通过STEP标准建立产品开发的全局共享信息模型，利用PDM软件集成和封装CAD／CAE及其它产品设计过程中用到的应用软件；平台也集成了甘蔗收获机械设计、分析和评价专家系统，专家系统采用模糊评价的方法对开发过程设计和仿真分析的结果进行评价和决策。集成平台支持甘蔗收获机械可视化虚拟产品集成化的团队设计及收获机械系列化产品开发。     

商业CAD系统中的协作设计

商业CAD系统是一个支持多个设计者并行设计、协作完成同一设计任务的CAD系统.文中提出了基于客户／服务器结构、支持同步和异步设计的协作设计模型.并具体介绍了协作管理中的角色管理、任务管理、群体感知管理和数据管理的实现技术和技巧.     

Design gene based secure mechanism for collaborative product development

In collaborative product development, a CAD model needs to be effectively shared among partners to facilitate co-design. In the meantime, it is essential to preserve the intellectual property information (design knowledge) of the shared CAD. To resolve the above dilemma, this paper presents a novel approach to share CAD models to support collaboration, as well as conserving confidential design knowledge in the models. The motivation of the approach is to develop collaborative mechanisms pertaining to an innovative concept of design genes, which imitate biological genes that are responsible for the heritable characteristics of an organism during evolving. The approach consists of the following steps. Firstly, design genes are defined to represent the design knowledge in CAD models. Secondly, a filter is introduced to retrieve design genes from the CAD model flexibly. An encryption algorithm is then designed to encrypt the design genes, and ensure the geometrical validity of the model to support effective collaboration. Finally, case studies are used to validate the developed approach. The complexity of the case studies can demonstrate that the approach is applicable to real-world application scenarios.     

A CAD-CAE integration approach using feature-based multi-resolution and multi-abstraction modelling techniques

In spite of the widespread use of CAD systems for design and CAE systems for analysis, the two processes are not well integrated because CAD and CAE models inherently use different types of geometric models and there currently exists no generic, unified model that allows both design and analysis information to be specified and shared. In this paper, a new approach called the CAD/CAE-integrated approach is proposed and implemented by a feature-based non-manifold modelling system. The system creates and manipulates a single master model containing different types of all of the geometric models required for CAD and CAE. Both a solid model (for CAD) and a non-manifold model (for CAE) are immediately extracted from the master model through a selection process. If a design change is required, the master model is modified by the feature modelling capabilities of the system. As a result, the design and analysis models are modified simultaneously and maintained consistently. This system also supports feature-based multi-resolution and multi-abstraction modelling capabilities providing the CAD model at different levels of detail and the CAE model at various levels of abstraction.     

Internet-enabled real-time collaborative assembly modeling via an e-Assembly system: status and promise

Collaborative CAD systems enabling collaboration in computer-aided design processes among distributed designers are gaining more and more attention. Yet, such systems, especially in support of collaborative assembly modeling, are hardly achievable. Targeting this gap, this paper addresses an Internet-enabled real-time collaborative assembly modeling system, named e-Assembly. This emerging system allows a group of geographically dispersed designers to jointly build an assembly model in real time over the Internet. In particular, this paper proposes a new assembly representation, called Collaborative Assembly Representation, for Internet-based collaborative assembly modeling. Also, collaborative assembly constraint satisfaction is addressed based on three coordination rules embedded in e-Assembly. Furthermore, the system architecture and realization of e-Assembly are provided. Finally, a prototypic implementation of e-Assembly is presented for demonstration and discussion.