【作者】 李晓武；

【导师】 雷毅；

【作者基本信息】 北京航空航天大学 ， 航空宇航制造工程， 2005， 博士

【摘要】 21世纪制造业竞争的焦点是创新产品的开发,CAD是实现产品创新设计的主要工具和手段。论文工作围绕支持产品创新设计的CAD造型若干关键技术问题展开,完成了以下工作: 一,论述了创新设计在产品开发中的重要性。介绍了产品创新设计和创造性思维的内涵及国内外研究现状等,阐述了CAD是实现产品创新设计的重要工具,分析了CAD/CAM系统在支持创新设计方面的现状及存在的不足,指出了当前CAD系统对产品创新设计进一步支持需要解决的问题。 二,系统地研究了支持创造性设计思维的CAD智能化操作工具——拖放式Drag&Drop技术,提出了计算机对象拖放Drag&Drop技术在CAD中的实现模型。对Drag&Drop技术的应用做了归纳分类,分别分析了基于约束的变量化设计的Drag&Drop实现和利用对象拖放技术的Drag&Drop实现原理、数据结构及实现步骤等,旨在为创新设计CAD系统的交互提供借鉴。 三,研究了支持创新设计的线面映射技术。阐述了平面曲线向自由曲面映射的概念,总结了线面映射的性质。提出了构造映射曲线的两种方法:曲线离散法和迭代生成法,并给出了具体的算法步骤。详细论述了平面曲线向自由曲面映射的原理和方法,将线面映射理论分别应用于变长度映射和向可展曲面的定长度映射;探讨了平面曲线向非可展曲面的最小失真映射问题;并以轮胎模具的花纹造型为例,阐述了平面曲线向自由曲面映射在工程中的实际应用。 四,研究了支持创新设计的曲面上曲线的构造实现问题。提出了一种限制在曲面上的曲线插值方法。论述了曲面上曲线的定义及性质,总结了曲面上曲线的精确和逼近实现方法。并基于线面映射理论实现了限制在曲面上曲线的插值,给出详细算法步骤,分析了插值效果,对造成算法不稳定情况做了处理。 五,提出了利用接口技术,通过曲面和实体两个几何平台之间进行数据转换,从而实现实体曲面统一造型的方法,这样既能够充分发挥曲面和实体各自的造型优势,也保证了造型的有效可靠性。研究了支持创新设计的曲面和实体造型融合的原理及方法。探讨了曲面实体统一造型技术。以CAXA制造工程师系统中曲面模块和Parasolid实体模块的曲面数据转换为例,研究了实体造型和曲面造型之间数据类型转换的方法。更多还原

【Abstract】 In the 21th century, the competition of manufacturing company is focused on the creative products. As it is known, CAD is the main tool for the products design. In this paper some CAD key techniques for supporting creative product design are studied. The dissertation is summarized as follows:(1) Firstly, the importance of supporting creative product design is represented. And the description of the creative design and the creative thought are summarized, as well as the study situation. CAD is the important tool for creative products design, and it supports the create design in many ways. There are still some problem to studying for making progress of the design creativity and competition.(2) Secondly, the CAD intelligent interface tool-Drag&Drop technology isstudied for supporting the creative modeling motion. There are several kinds of Drag&Drop technology in CAD, which can be classified in Extended Variational Design Technology (VGX) or Object Link and Embed (OLE). The paper analyses the application of the two Drag&Drop methods in CAD in detail, especially, the OLE Drag&Drap technology, which can be used for reference in creative design.(3) Thirdly, two way of constructing the mapping curve are given: curve subdivision and iterative method, and the algorithms are also presented, the mapping theory and method are analyzed, based the mapping theory, the variant length mapping of planar curve to free surface and the same length mapping of planar curve to the spread surface are realized, the mapping of planar curve to free surface is discussed for the surface creative modeling. The definition of mapping of planar curve to free surface is proposed, and the characteristics are summarized. The method of the least distortion mapping of planar curve to free surface is also discussed. As the example, the mapping process from the planar two-dimensional tread patterns to tire surface is described.(4) Fourthly, one interpolation method of curve on free surface is given. The definition and characteristics of curve on free surface are described, the methods of the exact and approximate are summarized. Based the mapping of parametric curve to free surface, the curve interpolation limited on free surface is realized, the algorithm is also given, and the result is analyzed. The problem causing error is also solved.(5) Lastly, The method of transmitting the data between the two modeling platform of surface and solid can keep the advantage of the two technology, so it is given in this paper, forthe purpose of supporting creative design, the combination of solid modeling and surface modeling is studied. The paper summarizes the unified stucture of free surface and solid modeling. And based the CAD/CAM software, CAXA Manufacture Engineer, the hybrid approach of surface and solid are studied in detail, and the algorithms and functions from the CAXA Manufacture Engineer, surface to the Parasolid and from the Parasolid to CAXA Manufacture Engineer, are given.更多还原