【作者】 张军；

【导师】 卢碧红；

【作者基本信息】 大连交通大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 目前，激烈的市场竞争使产品更新换代频繁，要求企业做出快速反应。工业产品中自由曲线曲面设计由于三视图表达不清而难以进行CAD建模。利用逆向工程技术，可以有效缩短产品开发时间，提高市场竞争力，解决CAD建模中的难题。本文在全面分析国内外逆向工程领域研究现状的基础上，以钩锁铁蜡模样件作为应用对象，对复杂曲面产品的逆向设计进行了深入研究。研究工作主要包括以下内容： 1．样件的数字化 复杂曲面产品的样件数字化方法不仅影响产品的开发速度，而且间接决定了曲面重构的速度和质量。论文运用一级模糊综合评判方法研究了复杂曲面产品的数字化策略，并以钩锁铁蜡模为例，讨论了基于CMM的数据采集关键技术及采集数据的具体流程； 2．点云数据的预处理 针对散乱点云数据的特点，详细阐述了基于形状特征匹配的点云对齐方法。研究了散乱数据的误差修正和数据优化途径，对多种噪声点滤除方法和数据精简方式进行了对比分析，以找出满足应用需求的数据规范方法。并根据曲面重构的需要研究了点云特征的提取方法和曲面分块原则； 3．曲面重构 论文首先从工程应用的角度分析了NURBS曲线、曲面造型方法中各种参数对曲线、曲面重构质量的影响。在此基础上，本文提出采用网格法进行三维散乱点曲面重构。对散乱点曲面拟合分为两种基本类型：由点直接生成面以及由点—线—面的方式生成面，并对各类型曲面拟合的特点及适用场合进行了归纳总结。对曲面拼接，发现实现光顺拼接的关键因素是曲面边界的选择及曲面变化趋势，并依此提出了一种新的曲面拼接方法。对工程中的三边域曲面及Y型曲面等特殊形状的曲面重构给出了解决方案，对蒙皮法中出现的曲面畸变现象进行了具体分析，并通过边界规范化、数据延拓以及曲面裁剪等方法使曲面畸变得到控制。更多还原

【Abstract】 Presently, the drastic competitiveness in market, which make the products life cycles shorter and shorter, requires rapidly responding for enterprise. In industry design, the free-form shapes cannot be properly described in 3-D views so that the CAD models cannot be created. But reverse engineering (RE) technology can shorter the product development time, improve competitiveness, and overcome the special difficulties in industry design for free-form shapes. Based on the full analysis of the fields of the present research on the reverse engineering with home and foreign documents, this paper takes the wax model of Coupler knuckle lock as the object to do some in-depth research about the reverse engineering of complicated surface products. The research is as follows:1. The Model Digitizing The method of model digitizing not only influences the speed of development, but also indirectly determines the quality and speed of the reconstruction of curved surface. In this paper, it studied the digitization strategy of complicated curved surface utilizing the one-level fuzzy comprehensive judgment method. Moreover, taking the wax model of the Coupler knuckle lock for an example, it discussed the data collection technology based on CMM and the process of data handling.2. Pretreatment of Points Cloud According to the characteristic of scattered point cloud data, the issue elaborated in detail points cloud registration, which was based on the shape characteristic matching. Also, it studied the error correction and the data optimization method of scattered data, and compared the filtration method of multi-noise with the simplified method of data to find out the measurement plan of data that can satisfy the practical application. At the same time, on the basis of the need of the reconstruction of the curved surface, it researched the extract method of the更多还原