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1.
支持自顶向下设计的产品功能建模技术   总被引:1,自引:0,他引:1  
自顶向上的设计模式符合一般的设计规律,面对几何建模技术为主的各种CAD系统难以真正地对这一过程提供支持本文介绍了一种基于功能单元和功能特征的产品功能模型。它能够表达产品的功能结构和功能关系,并建立了对零件形状特征的功能约束。功能建模系统 基于特征的产品建模系统相连接,能够实现自顶向下的产品设计 。  相似文献   

2.
本文在就实体造型、尺寸公差建模、非簇建模、参数化建模、约束建模和特征建模等技术作简要的评述后,提出了在现有CAD系统基础上,实现产品特征建模系统开发的方法。系统利用特征定义将实体模型和特征模型紧密联系起来,特征识别和基于特征设计技术相互配合,使用户可自由地选取实体建模操作或特征建模操作来构造具有完整定义的产品模型。  相似文献   

3.
本文介绍了一种数据流分析技术,功能-信息分析法。这一方法明确了功能和信息对基于数据处理的现实系统,是其逻辑模型的两大基本要素,强调自顶向下逐层分解系统应立足于对功能和信息的分析。最后本文将功能-信息分析法应用于具体系统分析实例中。  相似文献   

4.
分析传统非功能需求定义的不足,基于需求分析阶段的系统抽象—"需求模型"重新定义非功能需求,规范并简化功能需求与非功能需求之间的关系。扩展面向特征的软件产品线建模方法,在特征模型中显式地建模功能需求、非功能需求、非功能需求类型以及它们之间的相互关系,沿用传统特征模型中固有的变化性建模机制建模并管理非功能需求的变化性,显式地复用与非功能需求相关的建模知识和资产,为进一步研究定量评估产品线变体质量的新技术奠定基础。设计了一个基于多视图的特征建模方法,指导开发者在迭代的过程中建模非功能需求和功能需求,支持关注点分离和模型的复杂性管控。实现了工具原型并进行了实例验证。  相似文献   

5.
基于特征语义的模型表示法研究   总被引:1,自引:1,他引:0  
为了更好地适应语义特征建模系统的需要,使CAD/CAID系统能够在特征中封装更多更复杂的语义,提高传统特征建模系统的效率,提出了一种基于特征语义的模型表示法。这种表示法通过特征语义来构建特征外形的各个表面,用细胞元模型来管理特征的各种元素,采用“面的完整性验证”代替传统的约束求解来验证用户操作的有效性。因此这种表示法不仅可以有效地表示产品模型的复杂语义,还可以大大提高语义特征建模系统的性能。实验表明,这种表示法有更强的实用性和适应性。  相似文献   

6.
本文通过对机械产品特征造型设计过程的分析,以EUCLID-IS、AUTOCAD等为软件平台,利用软件二次开发技术建立机械产品特征造型系统,论述了系统建模方法、系统结构及系统功能,阐明应用系统实现机械产品特征造型设计的方法和步骤。  相似文献   

7.
本文在功能特征建模方法的基础上,提出了组合广义功能特征的产品定义方法.用 该方法建立的组合广义功能特征信息模型,实现了产品组合结构的功能与组合几何特征之间 的映射,使得组合广义功能特征的相关设计过程可以交叉进行.  相似文献   

8.
论述产品CAD系统中的自顶向下设计方法,指出基于装配的CAD技术不仅可以保证实现产品的功能,而且能够充分体现设计者的设计意图,最后阐述该方法与CIM哲理、并行工程等的关系。  相似文献   

9.
本文归纳总结了面向集成的产品建模CAD系统的当前特征及其发展趋势,指出了其发展的主要研究内容,并由此提出了面向集成的产品建模系统新的体系结构,重点论述了基于约束的特征基产品描述方法。  相似文献   

10.
特征模型中非功能需求建模初探   总被引:3,自引:1,他引:3       下载免费PDF全文
在需求模型中准确、完整地规约与非功能需求(NFR)相关的语义是实现NFR的前提,也是需求建模的难点.本文探讨了特征模型中NFR的建模方法,该方法显式区分功能和非功能特征,根据精化关系将处于不同抽象层次上的非功能特征组织成树状结构,支持对NFR的系统化处理.该方法扩展特征模型以显式描述特定于NFR的语义,还给出了基于知识库(特别是中间件特征模型构成的知识库)识别并精化NFR的过程.该方法在奥运信息系统建模中得到了应用.  相似文献   

11.
To solve the existing problems during the ceramic mold enterprises product design and development process, the variable structure parametric design system based on modular of ceramic mold has been developed. The system uses the object-oriented technology and top-down design concept as a guide, establishes a ceramic mold parametric design process, divides the process of ceramic mold design into modules of different levels and creates a component model library based on the functional analysis. Expanding modular thinking to parts structure design level is an effective solution to the difficulty of changing the structure during the product design process. Examples show that the system can achieve a ceramic mold product design, improve design efficiency.  相似文献   

12.
To make MEMS structure design in a more intuitive way, and to support the “function to 3D shape to mask” design flow, a 3D feature based structure design framework and its corresponding key enabling techniques are presented on the basis of inverse design processes and top-down design methodologies. Driven by space mapping among function and structure, the feature model and its parameters are restricted with the bond graph represented simulation model, which is constructed with functional components in simulation library at the system-level. Conforming design rules, the hierarchic feature information model is established and finally can be cascaded down to a group of 3D feature nodes, which are all silicon fabrication oriented and defined on the top of CSG/B-rep 3D solid models. Surrounding this feature information model, the 2D mask deducing and fabrication parameters extraction at the fabrication-level can be performed for manufacturability checking, design/fabrication conflict feedback and fabrication process sequence generation. Taking a micro gap-closing actuator as an example, the structure design process is demonstrated in terms of this 3D feature modeling methodology.  相似文献   

13.
A process model based on product function and physical topology structure is proposed. This model decomposes the product top-down design process into module design task, part design task, design parameter and dependencies among them. According to the characteristics of the design process, an integrated collaborative design software framework is designed, which includes module task agent, part task agent and sensitivity-based collaborative design method for agents. The system is developed with Java and Web technologies and applied to the transmission design case to demonstrate its utilization and efficiency.  相似文献   

14.
This paper presents a new system framework for collaborative top-down assembly design. Different from current computer-aided design (CAD) systems, the framework allows a group of designers to collaboratively conduct product design in a top-down manner. In our framework, a multi-level and distributed assembly model is adopted to effectively support collaborative top-down assembly design. Meanwhile, fine-granularity collaborative design functionalities are provided. First, the coupled structural parameters involved in the distributed skeleton models of the product can be collaboratively determined by the correlative designers based on fuzzy and utility theory. Second, agent based design variation propagation is achieved to ensure the consistency of the multi-level and distributed assembly model during the whole design process. Third, collaborative design of assembly interfaces between the components assigned to different designers is supported. The prototype implementation shows that our framework works well for supporting practical collaborative top-down assembly design.  相似文献   

15.
The objective of this research is to develop a product modeling system to support mechanism design from the beginning of the design. The system must cope with two aspects of the design process which are top-down design and preliminary design. The current capabilities of existing CAD and CAE systems are not sufficient to support these two aspects. In this research a modeling method with an abstract model and an incompletely defined model is proposed. The mechanism is presented by constraints and depault values because constraints are suitable for representing the abstract model for a mechanism and default values are useful to supplement an incompletely defined model. We also introduce module-based modeling with mechanism modules corresponding directly to the functionalities of the mechanism and show that it is suitable for top-down design. Incomplete constraints are solved with default values so that the shape and location of the incompletely defined model can be modified and the motion of the model can be simulated. Finally, we illustrate the mechanism modeling system with some examples.  相似文献   

16.
本文介绍基于功能特征技术,设计变电系统倒闸操作主接线间隔线路图形的方法。通过图元功能特征(几何特征点、属性特征等)定义建立间隔线路动态父子关系链,以间隔线路组成一个系统的结构群体,采用人工智能的方法自动生成间隔线路图形,同时,基于特征点的约束机制,动态编辑线路模板中的子图元,以使主接线图形满足设计要求。  相似文献   

17.
To enable next generation CAD tools to effectively support top-down design of products, a top-down assembly design process is refined from the traditional product design process to better exhibit the recursive-execution and structure-evolvement characteristics of product design. Based on the top-down assembly design process, a multi-level assembly model is put forward to capture the abstract information, skeleton information and detailed information involved. The multi-level assembly model is a meta-level implementation and is easy to be extended. Moreover, the inheritance mechanisms are explored to ensure the feasibility of information transferring and conversion between different design phases in the top-down assembly design process. A top-down assembly design sample is analyzed at length to show the application effects of the multi-level assembly model and the relevant inheritance mechanisms. In addition, a practical topic about the model adaptation of existing CAD systems is also discussed for a broader application of the top-down assembly design. Finally, the conclusion of the work and the future directions for further exploration are given.  相似文献   

18.
With the boom of Internet Technology, it becomes possible to combine designers from different disciplines into one team to support product design globally. In this paper, a distributed collaborative product design environment is presented to support top-down process oriented product design. In conceptual design stage, the artifact is managed by semantic norm model (SNM). In SNM, the designers can define virtual components at early design stage and instantiate those components at later detailed design stage. By role-based access control (RBAC), different roles with corresponding permissions could be assigned to distributed designers, and the designers could concurrently modify different components of the product relevant to his or her roles. Based on the SNM and RBAC system, a distributed collaborative product design environment is developed and the top-down oriented product design process is demonstrated.  相似文献   

19.
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