【作者】 肖迪；

【导师】 张根保；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2002， 硕士

【摘要】 计算机科学的飞速发展、先进制造技术的广泛应用，正在促使传统的机械制造业发生根本性的变化。目前， CAD 、CAPP、CAM已取得了重大的突破和辉煌的成就。但是，机械产品公差设计的发展却远远地滞后于它们。公差设计的现状无法与目前CAD/CAPP/CAM集成发展的要求相适应，已成为制约它们进一步发展的瓶颈，迫切需要人们集中力量对计算机辅助尺寸和公差设计(CADT)进行深入的研究。利用计算机来辅助确定零件合适的尺寸标注模式、完成零件尺寸的自动化标注，是计算机辅助尺寸和公差设计研究领域中的一个重要部分，具有重大的工程意义。 本文就是在这样的一个大背景下，通过对“装配建模”、“尺寸链技术的应用”、 “尺寸标注模式的研究”等关键技术进行深入的研究，灵活应用图论中的相关数学工具，利用现代CAD环境所提供的比较方便的ActiveX技术，开发出相应的系统，确定出零件的功能尺寸和标注模式，实现零件尺寸标注的自动化。 在本文中完成了以下的工作：(1) 通过分析装配体中零部件之间的约束关系，建立装配体的有向功能关系图(OFRG)装配模型。(2) 运用图论中的最短路径搜索算法从装配模型中自动搜索出功能约束尺寸链，确定零件的功能尺寸。(3) 根据尺寸标注所要求的正确性、完整性、清晰性及合理性等原则，用改进了的图论中的生成树算法，确定出零件的非功能尺寸，完成零件尺寸标注模式的分析。(4) 自动对待标注的尺寸按方向进行分组、完成尺寸的优先级设定、在CAD环境下实现尺寸标注在零件图上的优化布置。(5) 结合实例，详细地介绍了机械装配建模和零件尺寸标注自动化技术的完整的实现过程。更多还原

【Abstract】 Rapid development of computer science and extensive application of Advanced Manufacturing Technology are bringing radical changes to traditional manufacturing. At present, great breakthrough and resplendent achievement have been made in CAD 、CAPP 、CAM. But the development of tolerancing design in mechanical product has lagged behind them greatly. The actuality of tolerancing design can’t adapt to the requirement of CAD/CAPP/CAM integrated developing and has become the bottleneck of their further development, which makes it necessary to do in-depth research on Computer Aided Dimensioning and Tolerancing(CADT). It is an important part in CADT field and of great significance in engineering to utilize computer to aid engineers to ascertain the suitable dimensioning mode, complete the automatic dimensioning of parts. In such a background, with the in-depth research on key techniques such as "assembly modeling"、 "application of dimension chain technique"、"research on dimensioning mode", the flexible application of correlative mathematical tools in Graph Theory, the utilization of relatively convenient ActiveX technique provided by CAD, the corresponding system has been developed to ascertain the functional dimensions and dimensioning mode, complete the automatic dimensioning of parts.In this paper, the following tasks have been accomplished: (1) Analyzing the constraint relation of parts to accomplish Oriented Functional Relationship Graph (OFRG) assembly modeling. (2) Utilizing the shortest path algorithm in Graph Theory to search functional dimension chains automatically in the assembly model and ascertain the functional dimensions of the part.(3) On the basis of the dimensioning principle of correctness, integrality, clearness and rationality, utilizing the modified spanning tree algorithm in Graph Theory to ascertain the non-functional dimensions, accomplish the dimensioning mode analysis of the part.(4) Automatically grouping dimensions by their directions, accomplishing the priority level enactment of dimensions and implementing the optimal lay of dimensions on the part drawing under the CAD environment.(5) Use the example to introducing the entire implementing process of the mechanical assembly modeling & automatic dimensioning technique on parts in detail.更多还原