导　　师： 骆少明

学科专业： 080203

授予学位： 硕士

作　　者： ;

机构地区： 广东工业大学

摘　　要： CAD模型的重建是反求工程的主要技术之一,如何快速有效地建立CAD模型已成为一个研究的热点。作为物体CAD模型重建的重要一环,自由曲线曲面的重构是复杂工业产品设计、制造及检测的重要技术手段之一,并深受CAD//CAM领域工程界的广泛重视。由于B样条方法是当前自由曲线曲面描述的最广为流行的技术,B样条曲线曲面是常用的形状设计工具,因此,本论文重点对B样条曲线曲面的重构进行研究。 在实际工作中,特别是在产品外形的概念设计阶段,设计者们常常注重的是产品外观的视觉效果。为了构造符合要求的曲线曲面,常常需要施加各种几何约束条件,这些约束条件会影响曲线曲面的拟合效果和形状的变化。因此,对带有约束条件的曲线曲面重构方法进行研究具有重要的意义。 本文把基于能量优化法的自由曲线曲面重构作为研究方向,在综合分析和研究国内外几何约束条件的基础上,提出了一种几何约束条件下的B样条曲线曲面重构方法。并针对传统方法中几何约束条件难以处理的问题,提出了基于自由度转换的处理方法。主要完成的工作和结论如下: 1、对B样条、B样条曲线曲面的基本理论和方法进行了论述;并系统地阐述了能量优化法曲线曲面重构的基本理论,建立了基于物理能量变形的有限元求解方法。 2、提出了几何约束条件下的B样条曲线重构方法。该方法可以避免传统方法中采样点数量、分布及参数化过程所带来的问题;并针对传统方法中约束条件难以处理的问题,提出了基于自由度转换的解决方法,结合有限元的求解方法,对几何约束条件进行处理,并通过应用实例验证了该方法的有效性。 3、提出了几何约束条件下的B样条曲面重构方法。描述了各种B样条曲面的几何约束条件,并将基于自� Reconstruction on CAD model is one of the main technology for reverse engineering, How to set up CAD model with efficient and speed is one of the most hot topic. As a part of reconstruction on CAD model, curve and surface reconstruction is significant technique to design, manufacture and check on complicated product, it is attached importance to represent free-from curve and surface, the emphases for this paper is CAD model reconstruction based on B-spline curve and B-spline surface.Within the practical application, especially concept design phase on product outline, designer only pay attention to effect of visual. To reconstruct curve and surface which can meet requirement, geometric constraint is necessary, the geometric constraint will affect the shape and fitting effect. Therefore, develop the CAD model reconstruction method for curve and surface with geometric constraint will be considerably beneficial to the application. The paper study the free-from curve and surface reconstruction based on energy optimization , after the systematically analysis of the theories and the research on geometric constraint, a new reconstruction method for B-spline curve and surface with geometric constraint is presented. The main work and conclusion in this paper are as below:1. Dissertate the theories and method on B-spline curve and B-spline surface, discuss the theory on reconstruction based on energy optimization method and set up the finite element method solution based on physics energy deformation.2. Put forward the reconstruction method of B-spline curve under geometric constraint , it can avoids the sampling and parameterization problems result from traditional interpolation and approximation, considering the traditional solution method is difficult for geometric constraint, a solution method based on degrees of freedom transform is presented, which can solve geometric constraint by the finite element method. The example results verified the practicability and validity of the method.3. Put forward the reconst

关 键 词： 反求工程 样条 能量优化法 几何约束条件 自由度转换

领　　域： [自动化与计算机技术] [自动化与计算机技术]