【作者】 李红波；

【导师】 陈文华； 赵东福； 李立新；

【作者基本信息】 浙江大学 ， 机械设计及理论， 2004， 硕士

【摘要】 本学位论文以组合曲面为研究对象，主要研究逆向工程中的数据通讯、数据预处理、子曲面边界识别及提取、数据压缩以及IGES输出等方面内容，为开发实用的逆向工程软件奠定理论基础。本论文共分七章，具体安排如下： 第一章阐述了逆向工程的基本概念及其主要应用场合。综述了与逆向工程相关的实物表面数据采集技术、曲面造型技术的研究进展。最后，给出了本学位论文的选题意义和主要研究内容。 第二章主要研究逆向工程中CMM与ReCad数据处理系统的通讯、离散数据线型自动提取技术等。从工程应用的角度出发，提出了数据通讯和线型自动提取的方法，从而为测量数据的光顺、压缩、特征提取和曲线曲面重建等研究工作奠定了基础。 第三章主要研究测量数据点的预处理、孔域拟实填补以及曲线模型重建技术。研究了基于圆率差分方法的交互光顺技术，对测点数据进行交互光顺处理，剔除测点数据中的噪声信息，使曲线光顺性达到设计要求，保证曲面的反求质量；同时，对孔域和不完整的测量信息进行拟实填补；并分析了NURBS曲线重建的步骤及其方法。 第四章系统地研究了根据截面扫描线信息，提取组合曲面子曲面边界特征线的方法。提出了利用圆率线及圆率差分突变来交互拾取曲线特征点的方法，实现了特征点的识别和提取。并分析了组合曲面子曲面边界的重建技术。 第五章主要研究了多义线数据压缩、ReCad数据处理系统与商业CAD／CAM系统的接口设计技术。提出了多义线线性压缩的方法，在保证曲线形状特征的前提下，对空间多义线实现了大比率压缩。通过与商业CAD／CAM系统的接口设计，可以充分利用商业CAD／CAM系统实现曲面造型、加工编程等功能。 第六章给出了ReCad数据处理系统的开发实例及部分运行实例，证明了本文提出的算法和方法的合理性、可行性。 第七章给出了本学位论文的结论和进一步研究的展望。更多还原

【Abstract】 This dissertation mainly research on data communication, pre-processing, combined surfaces boundary segmentation & pick-up, data compression and IGES export technologies in reverse engineering about the combined surfaces, in order to establish the basic technologies for development of reverse engineering software orient to the combined surfaces. Seven chapters are included in this dissertation.In chapter 1, some concepts on reverse engineering are briefly introduces firstly. Then, some considerable studies on data collection, surfaces modeling in reverse engineering are discussed in detail. Finally, the meanings of this projept are pointed out and the research contents are summarized.Data communication technology between CMM and ReCad data process system and automatic creation technology of the line-type based on scattered data are mainly studied and discussed in chapter 2. The methods of data communication and automatic creation of the line-style are proposed from the view of engineering application in order to make a foundation for the study of curve fairing, data compression, extracting feature points and surfaces modeling etc.Some pre-processing technology of measurement data and curve modeling are systemic researched in chapter 3. First, interactive curve fairing technology based on curvature difference is studied. Through interactive smoothing the measurement data, the noise data would be deleted. Sequentially, a new curve fairness procedure is proposed to meet the requirement of curve design and guarantee quality of surfaces modeling. Second, the half-baked data at hole area and some situation where that data is lacked are filled in because of measurement method. Finally, the methods and steps of NURBS curve modeling are analyzed further.The technology on extracting boundary curves of patches in the combined surface according to cross-section scanning beam information is studied in chapter 4. The research contents in this chapter include the methods of extracting feature points and boundary curves modeling. The method that interactively extract feature points based on curvature difference break is proposed to complete extracting feature points. Finally, how to link the extracting feature points into feature curves is analyzed.Data compression method and interface design between ReCad data process system and CAD/CAM are proposed in chapter 5. The data compression method that may realize a high compression ratio is proposed to meet curves modeling requirement. In order to make fully use of commercial CAD/CAM system resource to complete surface modeling and NC process function, IGES export interface is designed.In chapter 6, some ReCad system running instances are demonstrated. They prove that the proposed algorithms and methods in this dissertation are feasibility and rationality.Some results are included in the last chapter. Some futures tasks on this project are also pointed out.更多还原