【作者】 徐旭松；

【导师】 杨将新； 曹衍龙；

【作者基本信息】 浙江大学 ， 机械制造及其自动化， 2008， 博士

【摘要】 本文结合国家自然科学基金项目“基于新一代GPS标准体系的计算机辅助功能公差设计理论与方法(50775204)”、“基于GPS的三维公差建模方法与技术研究(50505046)”,就公差建模与表示、功能公差方案规范设计、功能公差分析与综合以及面向可装配性的公差分析等技术开展了研究,提出了“基于新一代GPS的功能公差设计理论与方法的研究”的博士论文。第1章:论述了新一代GPS的制定和跟踪研究情况,综述了计算机辅助公差设计的发展历史和研究现状,讨论了本课题的研究背景和意义;最后,给出了本论文的主要研究内容、总体框架及创新点。第2章:结合新一代GPS标准,给出了产品几何的一些基本定义,分析了几何尺寸与公差(GD&T)的信息构成、公差项目分类、公差原则等;应用与ISO/TC213-GPS一致的TTRS、MGRE、SDT等研究了三维公差域参数化建模理论,并针对几种常见的恒定类表面进行了实例研究。第3章:基于恒定类研究了装配体定位接点的分类及其优先次序的确定原则,对现有装配有向图进行了改进,增加了装配定位约束的表达;研究了几何功能需求的表达与分解方法,基于改进装配有向图研究了零件-零件之间分界面的公差规范设计技术;给出了公差域恒定度的定义和标识,研究了基于拓扑的基准参考框架的验证规则;提出了一种几何功能需求-几何规范的功能公差方案设计过程和方法;给出了一个简单装配体实例及其公差方案设计结果。第4章:在公差建模的基础上,以齐次坐标变换来描述装配体中的几何变动传播,建立了包含零件公差信息和装配间隙信息的装配公差分析矩阵模型,构建了公差回路的矩阵表达式,用实例说明了面向功能性和可装配性的公差分析过程。第5章:提出了一种基于变动量SDT表达的功能公差综合方案;在公差域-偏差域映射的基础上,研究了公差-成本模型到偏差-成本模型的映射,给出了几何功能需求约束、装配连接约束的SDT表达;并用一个简单实例说明公差综合优化过程。第6章:将CAD模型中零件模型及其特征用点集形式表示;采用齐次坐标变换来描述工艺系统各组成部分的空间关系,建立了工艺系统各组件的几何误差累积模型;将制造过程看作是刀具轨迹形成的点集更新被加工零件点集的过程,可生成表达加工后零件的点集矩阵;用实例进行了Monte-Carlo仿真分析,从而在公差设计阶段就考虑了制造几何变动,实现公差并行设计。第7章:在理论研究的基础上,进行了计算机辅助功能公差设计(CAFT)原型系统初步开发;给出了CAFT原型系统各个模块的功能,结合实例分析了该原型系统的工作流程。第8章:概括了全文的主要研究内容,并对计算机辅助公差设计研究进行了展望。更多还原

【Abstract】 Based on the research of National Nature Science Fund Project "Research on Theories and Methods of Computer Aided Functional Tolerancing based on new generation GPS (No. 50775204)" and "Research on 3D Tolerance Modeling based on GPS (No. 50505046)", tolerance modeling and representation, functional tolerance specification, functional tolerance analysis and synthesis, manufacturing oriented tolerance analysis, etc. are studied.In chapter 1, the enactment and tracking study of new generation GPS are expounded, the State-of-the-arts of computer aided tolerancing (CAT) are summarized and the research background and significance of this project are discussed. Finally, the main contents, the overall frame and innovation points of this dissertation are given.In chapter 2, some basic definitions consistent with new generation GPS standard of geometric product are presented. The information composing of geometric dimensioning and tolerancing (GD&T), tolerance type, tolerance principle, etc are analyzed. The theory of 3D tolerance parameterized modeling is studied based on the concept of TTRS, MGRE and SDT, etc. And, case study of tolerance modeling of several familiar features belong to some invariance class are done.In chapter 3, the classification of positioning joints of part assembling based on the definition of invariance class and the principle of ascertaining its preponderance order are studied. The assembly oriented graph (AOG) which is already in existence has been improved and the expression of assembly poisoning constraint is added in AOG. The methods of representing and decomposing of functional geometrical requirement are studied. Then, the tolerance specification technology of interface between part-part based on the improved AOG is studied. The definition of invariant DOF and mark of tolerance zone are given. General rules for validating datum reference frame are studied. The functional tolerancing process and method of geometrical functional requirement-geometrical specification are given. Lastly, a simple assembly example and functional tolerance specification result are presented.In chapter 4, based on the tolerance modeling of feature, the propagation and accumulation of geometrical variation in assembly are described using HTM (homogeneous transformation matrix), and the tolerance accumulation model including tolerance information of part and gap information of part-part are established. Then, tolerance loop and matrix equation is established. Several examples are used to explain the tolerance analysis process oriented to assembly feasibility and functionality.In chapter 5, a tolerance synthesis scheme is put forward. On the base of mapping of tolerance zone to deviation space, the mapping of cost-tolerace model to cost-deviation model is studied. The small displacement torsor representation of geometric requirement constaints, assembly connection constaints are studied, and a simple example is used to demonstrate the tolerance synthesis process.In chapter 6, CAD model of part and its feature are represented by a group of points. The space relations of each component in process system are described by homogeneous transformation, and then stack-up model of geometric error of process system is established. Machining process can be regarded as the points-group of tool path updating the points-group of part. The manufacturing geometric variation of feature/surface of part is analyzed by Monte-Carlo simulation. Thereby, manufacturing geometric variation can be considered in tolerance design stage and concurrent tolerance design is actualized.In chapter 7, the prototype system for Computer Aided Functional Tolerancing(CAFT) is preliminary developed. The function of each module and workflow of CAFT system are analyzedIn chapter 8, the main content of the dissertation research is summarized, and the prospect of Computer Aided Tolerancing research is presented.更多还原