面向对象产品装配模型的研究

对产品装配表达要求、产品设计过程要求进行了深入的探讨，基于产品装配对象的分析，提出了一个面向对象的产品装配模型。设计和实现了装配模型类及类层次结构，对该模型在产品信息的表达和管理，面向对象特性，支持Top-Down设计等方面进行了讨论和分析。该装配模型在软件系统设计中得到了很好的应用。     

CAD中的产品信息建模技术

产品信息建模就是一种核心的信息处理技术,是CAD中所要解决的一个核心技术问题。 产品信息是定义一个零件、零件的装配体在其生命周期中的几何形状,功能以及行为的所有数据,它包含几何、拓扑、精度、材料、管理、装配关系、属性、技术等方面的特征。建立产品信息模型的目的是为了将所关注的客观事物抽象成形式化描述,以便于计算机处理。从整个CAD技术发展的历程来看,产品信息模型的表示往往决定着系统的功能,同时也决定了系统的相应的算法、数据结构、用户界面乃至系统结构。对产品信息模型的研究,随着CAD实用化程度的提高,经历了由简单到复杂,由几何模型到集成化产品信息模型的发展历程。     

虚拟环境中装配设计语义的表达、传递与转化研究

研究了虚拟环境产品装配建模过程中装配语义的表达、装配语义与装配约束的转化技术,提出了采用语义－约束图对装配设计语义与约束进行维护。通过语义－约束图可以从语义层次和约束层次对产品装配模型进行编辑和维护。提出了采用模糊参量表达和处理产品装配设计中的模糊语义。基于模糊参量的语义表达不仅为设计信息输入提供了更大的自由度,而且扩展了计算机对模糊信息的处理能力,有利于产品设计意图的维护。通过产品装配信息从抽象到具体、从模糊到精确的转化,实现了虚拟装配设计系统对抽象、模糊设计信息的表达、传递与处理。     

基于符号的装配建模方法研究

在以装配符号的定义实现产品装配设计语义抽象表达的基础上，对产品装配建模过程中装配语义的表达、装配语义与装配约束的转化及维护技术进行研究．提出基于装配符号的约束规则集描述，实现产品装配设计信息的传递，并采用装配符号关系图对产品装配设计语义与约束进行动态维护．通过产品装配信息从抽象到具体、从模糊到精确的转化，实现产品装配设计系统对抽象、模糊、动态关联的产品装配设计信息的表达、传递和维护．     

基于分布式虚拟环境的装配约束语义模型

装配约束是用来支持分布式虚拟环境中装配交互操作的关键信息．装配约束信息的抽象性关系到对装配单元行为的支持力度，装配约束信息的组织机制决定了分布式虚拟装配计算机实现的效率．针对目前装配约束的抽象和使用方面存在的问题，首先研究装配约束的语义抽象与表达，从产品装配应用域中捕获知识，提取共性，归纳装配约束基本语义并形式化表达；然后提出一种扩展对象语义建模方法，通过该方法对装配约束语义进行组织，赋予其功能行为特性，构建装配约束语义模型．通过VEADAM系统实例，装配约束语义模型能够有效地支持分布式虚拟装配的实现，并能很好地适应应用的变化和扩展．     

基地Pro／E的产品装配建模系统

本文介绍一个以产品装配模型为中心，基于Ｐｒｏ／Ｅ的产品装配建模系统。该系统在产品装配模型的支持下能有效地提高产品的设计质量，支持产品的并行设计，并且能有效地满足快速多变的产品市场需求。     

基于Pro/E的产品装配建模系统

本文介绍一个以产品装配模型为中心，基于Ｐｒｏ／Ｅ的产品装配建模系统。该系统在产品装配模型的支持下能有效地提高产品的设计质量，支持产品的并行设计，并且能有效地满足快速多变的产品市场需求     

基于Web的协同设计环境下产品生命周期管理系统研究

本文在分析了产品生命周期系统的需求之后，提出了协同环境下的产品生命周期管理系统功能模型。分析了产品统一信息平台模型。其目的是为企业提供一个支持协同设计的开放式、共享式的产品开发环境。     

并行工程环境下基于约束的产品设计理论及应用系统

本文从理论与实践上阐述了基于约束的设计方法如何在并行工程环境下实现面向产品生命周期的设计。首先介绍了基于约束设计方法的基本原理，包括表达产品生命周期内的信息以建立约束网络，和对设计问题的优化求解过程，即建立对约束网络的搜索算法。在此基础上，探讨了如何支持约束设计的并行设计智能框架工具（ＣＩＤＡＴ）以实现面向产品生命周期的设计。     

复杂约束条件下的分层装配模型

为在装配建模过程中保证信息的完整性,提出基于装配对象属性的分层约束装配模型。以需求块的概念为基础,对装配对象采用先分块再分层的方法进行分组,分析各块、各层之间复杂的约束关系,构建分层约束装配图,完成装配顺序算法的设计。实验结果表明,该模型能有效表达装配形成过程的顺序,实现装配关系的分解和时序化,对象之间的交互过程简单真实且便于操作。     

A conceptual approach for the die structure design

A large number of decisions are made during the conceptual design stage which is characterized by a lack of complete geometric information. While existing CAD systems supporting the geometric aspects of design have had little impact at the conceptual design stage. To support the conceptual die design and the top–down design process, a new concept called conceptual assembly modeling framework (CAMF) is presented in this paper. Firstly, the framework employs the zigzag function-symbol mapping to implement the function design of the die. From the easily understood analytical results of the function-symbol mapping matrix, the designer can evaluate the quality of a proposed die concept. Secondly, a new method—logic assembly modeling is proposed using logic components in this framework to satisfy the characteristic of the conceptual die design. Representing shapes and spatial relations in logic can provide a natural, intuitive method of developing complete computer systems for reasoning about die construction design at the conceptual stage. The logic assembly which consists of logic components is an innovative representation that provides a natural link between the function design of the die and the detailed geometric design.     

Knowledge-based approach and system for assembly oriented design,Part I: the approach

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the first part of the report (Part I), which mainly proposes a knowledge-based approach and framework for intelligent assembly oriented design. The proposed approach focuses on the integration of product design, assemblability analysis and evaluation, and design for assembly with economical analysis. It differs from the existing approaches adopting the part-first bottom-up modeling technique, in which a hybrid model related to design problem-solving including function–behavior–structure model, feature-based geometric model, and parametric constraint model is used as a comprehensive intelligent framework for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. Through the use of intelligent approach and framework, concurrent engineering knowledge can be effectively incorporated into the assembly design process, and a knowledge-based expert design system can be implemented.     

Knowledge-based approach and system for assembly-oriented design,Part II: the system implementation

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the second part of the report (Part II). It will focus on the development of knowledge-based expert design system for assembly oriented design. The knowledge-based assembly oriented design system, i.e., the assembly oriented design expert system (AODES) is constructed to integrate assembly modeling and design, assembly planning, assemblability analysis and evaluation within a concurrent engineering environment. This intelligent system is implemented by integrating object-oriented representation, constraint-based modeling, rule-based reasoning, truth maintenance, and interfacing to database management system and CAD module, in which fuzzy logic based knowledge representation and inference technique are also applied to deal with uncertain data and knowledge in the design process. The developed system differs from the existing systems adopting part-first bottom-up modeling technique, in which a comprehensive intelligent framework is used for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. It is able to help obtain better design ideas, provide users with suggestions so as to create and improve a design, and therefore give users the possibility to assess and reduce the total production cost at an early stage during the design process. Through the use of the system, the concurrent engineering knowledge can be effectively incorporated into the assembly design process in an integrated manner. A case assembly design shows that the intelligent modeling and design system is feasible.     

支持多学科设计优化的集成产品过程建模方法

针对当前主要的设计过程建模方法缺乏表达复杂产品多学科设计过程中资源的组织调用和协作方式等信息,提出一种支持复杂产品多学科设计优化的设计路线图框架过程建模方法.从全面表达设计过程信息的角度出发,描述产品多学科设计优化过程中的主要活动及其协同关系,建立支持多学科设计优化的过程模型;在此基础上,给出了多学科设计优化的过程规划方法,以降低产品设计过程中的迭代,通过构建支持多学科设计优化的集成产品设计过程结构框架,实现产品多学科设计优化的过程集成.最后通过已开发的多学科系统集成平台,应用具体设计实例验证了整套方法的有效性.     

一种面向方案设计的装配建模表示方法

ＣＡＤ系统对方案设计支持的关键是建立独立于几何细节而又表达的功构关系的装配模型,本文试图运用逻辑装配单元的定义来实现产品功能需求和结构表现间的有效关联,分别讨论了方案设计中功能描述和几何构形表示方式,形式化表达了方案设计的逻辑造型和装配建模过程,给出了支持自顶向下方案设计的装配模板定义,为方案设计的计算机辅助实现作了有益的尝试。     

Web-based modular interface geometries with constraints in assembly models

The use of a modular technique in modeling for assembly can improve design efficiency and reduce the cost of product development. This paper presents an approach to an assembly model that was built using modular interface geometries. This paper proposes a novel, hybrid modular design strategy instead of the traditional, top-down design process. The curve-joint method is used as a simplified process for converting a 3D solid model to a skeleton model with interface geometries in modeling for assembly. This research builds assembly interface geometries with their constraints in the assembly model instead of using information about individual assembly parts for the product. These interface geometries are easy to share, and they deliver the design requirements properly. They also ensure that minimal efforts will be required in the design change process. By implementing this method, the constraints of the features in modular assembly parts can be transferred to interface geometries. Designers can easily add, replace, and delete design parts in the modular product. Module interaction for application programmed interface (MIAPI) is developed using HTML and JavaScript. The module structure of products can be verified via the web-based Internet in VRML format. These simplified assembly models that have fewer constraints allow design project managers to simulate the functioning of the product in the modularized design before the prototype is built. By using the assembly models, customers can easily choose various modules to assemble the exact products they are seeking via the Internet process. A desk lamp model is used as the example for implementation to validate the feasibility of this research.     

A knowledge intensive multi-agent framework for cooperative/collaborative design modeling and decision support of assemblies

Multi-agent modeling has emerged as a promising discipline for dealing with decision making process in distributed information system applications. One of such applications is the modeling of distributed design or manufacturing processes which can link up various designs or manufacturing processes to form a virtual consortium on a global basis. This paper proposes a novel knowledge intensive multi-agent cooperative/collaborative framework for concurrent intelligent design and assembly planning, which integrates product design, design for assembly, assembly planning, assembly system design, and assembly simulation subjected to econo-technical evaluations. An AI protocol based method is proposed to facilitate the integration of intelligent agents for assembly design, planning, evaluation and simulation process. A unified class of knowledge intensive Petri nets is defined using the O-O knowledge-based Petri net approach and used as an AI protocol for handling both the integration and the negotiation problems among multi-agents. The detailed cooperative/collaborative mechanism and algorithms are given based on the knowledge objects cooperation formalisms. As such, the assembly-oriented design system can easily be implemented under the multi-agent-based knowledge-intensive Petri net framework with concurrent integration of multiple cooperative knowledge sources and software. Thus, product design and assembly planning can be carried out simultaneously and intelligently in an entirely computer-aided concurrent design and assembly planning system.