【作者】 吴春侗；

【导师】 杨将新；

【作者基本信息】 浙江大学 ， 机械制造及其自动化， 2003， 硕士

【摘要】 本文结合国家自然科学基金项目“综合公差计算机辅助设计系统研究”(59705022)和“基于产品几何技术规范的集成公差设计理论与方法”(50275136)，研究了面向三维装配图的装配尺寸链自动生成技术，并开发了其原型系统。论文的主要研究内容如下：第一章：在分析计算机辅助公差设计系统、尺寸链自动生成技术的发展历史和研究现状的基础上，提出了本论文研究的主要内容和结构安排。第二章：介绍了产品几何技术规范(GPS)的基本概念；然后引入了ISO／TC213公差语义定义和特征类型，阐述了几何规范的内容、TTRS理论及特征的几种分类。第三章：研究了MDT的约束机制，分析了MDT支持的三种约束：尺寸约束、几何约束和装配约束的特点。结合ISO／TC213的特征类型和变动几何约束理论，提出了面向尺寸链的变动几何约束网络及其生成方法。第四章：在研究装配特征的基础上，分析了几种常用的装配信息模型；采用了自上而下的装配数据库方式，结合公差系统的特点改进了面向尺寸链的装配数据库，并软件实现之，最后给出了该数据库中的特征类、零件类和装配类的定义。第五章：提出了面向三维装配图的尺寸链自动生成技术。其原理为：在装配图上指定封闭环后，系统在装配图中提取出实体的所有装配约束关系，并获得相关尺寸信息，从而生成面向尺寸链的变动几何约束网络，通过搜索其最短路径自动生成装配尺寸链。第六章：阐述了面向三维装配图的尺寸链自动生成原型系统。第七章：对全文进行总结；对计算机辅助公差分析系统需进一步开展的工作进行了探讨和展望。更多还原

【Abstract】 Based on the "Study on Computer Aided Tolerancing System" and "Design Theory of Integration Tolerance based on Geometrical Product Specifications" (National Nature Science Fund Project, No: 59705022, 50275136), the technology of the auto-generation of dimension chain faced to 3D assembly drawing is presented. The prototype system is developed and proved by examples.In the first chapter, State-of-the-arts of computer aided tolerancing (CAT) system at home and abroad are summarized. The technology of the auto-generation of dimension chain is also analyzed. Main contents and general structure scheme of this dissertation are present.In the second chapter, the concept of geometrical product specifications (GPS) is introduced. Based on tolerance definition and feature type defined by ISO/TC 213, contents of the geometrical specifications, TTRS theory and several sorts of feature are analyzed.In the third chapter, the constraints mechanism of MDT is studied. Dimension constraints, geometric constraints and assembly constraints of MDT are analyzed. Combined with new feature type defined by ISO/TC 213 and Variational geometric constraints (VGC) theory, a kinds of Variational geometric constraints network (VGCN) faced to dimension chain is proposed.In the fourth chapter, the assembly characteristic is studied. Several common assembly information models are analyzed. Top-down assembly database way is adopted and the assembly information model is improved with the concern of the characters of the CAT. The assembly database faced to dimension chain is put forward and realized. At last, the definition of the part class, assembly class and feature class of the assemble database are given.In the fifth chapter, the auto-generation principle of the dimension chain faced to 3D assemble drawing is put forward. First, the closing loop is specified in the assembly drawing by the user. Then system can get the assembly constraints from the drawing and generate the VGCN faced to the dimension chain. The parts’ related dimension information is also obtained. The dimension chain is auto-generated later.In the sixth chapter, the prototype system for auto-generation of dimension chain faced to 3D assembly drawing is introduced.In the seventh chapter, all of the work in this dissertation is summed up. The future research of computer-aided tolerancing is prospected.更多还原