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1、上海交通大学硕士学位论文参数化的汽车车身设计姓名：许凯申请学位级别：硕士专业：机械设计及理论指导教师：赵新明20070201上海交通大学硕士学位论文 摘 要第 I 页参数化的汽车车身设计摘 要参数化的汽车车身设计摘 要车身设计在整车的开发中变得越来越关键和重要，对汽车车身造型 的设计与修改提出了越来越高的要求。传统的车身设计方法设计周期 长，费时费力，修改困难，不能满足这一需要。本文对曲面的参数化设 计与修改方法进行研究，实现了单个曲面的参数化设计及修改以及曲面 之间的关联更新，并将其应用于汽车车身造型设计，得到较好的效果。 该课题的研究具有实用价值。 在汽车车身曲面的设计过程中，曲面的设计与
2、修改以及曲面之间的 关联更新是两个关键问题。根据曲面的构建方式和设计人员直观的修改 角度，对车身曲面进行分块和建模，设定曲面的修改方式，将曲面的修 改合理地转化为曲线的修改。现有的 B 样条的修改理论不能给设计人员 很大的自由度，文中将“能量最小法”应用于 B 样条曲线修改，首次提 出了“B 样条曲线局部修改算法” ，用曲线上的三个点，分别直观地表 示曲线的修改区间和修改目标点，实现对 B 样条曲线上的任意曲线区间 的修改，并将该算法用在基于 UG 的曲面设计和修改中，根据实际需要 对该算法进行了改进。在草图曲线的修改中，优化了对称的草图曲线的 尺寸标注和修改，把 Windows 程序的消息发
3、送、处理机制，和 Windows API 函数运用于高亮显示正在修改的尺寸，给设计人员直观的显示。为 了建立曲面之间的关联，将曲面之间的约束关系用“关联参数”表示， 提出了设定关联参数的方法以及注意点。讨论了关联参数的唯一性，处 理循环影响多个曲面的关联参数的方法，曲面的构建顺序对关联参数选 择的影响等，并且将曲面的设计与修改以及曲面之间的关联更新的方法 在汽车车身曲面造型设计中加以应用，给出了关联参数为曲线和点的实 例。 最后本文给出了参数化、模块化的汽车车身设计的框架，说明了该 设计的基本方法和设计步骤，从而更大程度地提高设计效率，更大限度上海交通大学硕士学位论文 摘 要第 II 页地重用
4、已有组件。 本文使用 VC+编写了实例中的车身参数化设计功能的程序，生成 的动态连接库无缝集成在 UG 的使用环境中，实现了实例中的车身曲面 的参数化设计和修改。 车身的参数化设计降低对设计人员的设计经验和理论，计算机图形 学以及 CAD 软件操作等方面的要求，修改过程符合设计人员的设计思 想，使车身的设计和修改做到快、简、省。关键词：关键词：参数化设计，车身设计，B 样条曲线局部修改算法，关联参数，模块化，UG 应用开发上海交通大学硕士学位论文 ABSTRACT第 III 页THE PARAMETRIC DESIGN OF AUTOMOTIVE BODYABSTRACTThe design
5、for automotive body is becoming more and more significant in the development of an automobile, it also makes higher require of the design and modification of the body styling. The traditional design method can not meet this need because of its long development period, wasting more time and energy, t
6、he difficulty in modification and high request of the designers capability. In this thesis, the method of parametric design and modification for the surface is discussed. It is accomplished that only one piece of surface is designed and modified parametriclly. So is the related update between the su
7、rfaces. All those methods is applied to styling design of automotive body, which leads to good effects. This project has practical value. In the design process for automotive body, two aspects is very significant: one is the modification of the independent surface and another is the update between t
8、he surfaces, when a piece of surface is modified. In the sample, according to the methods for creating various surfaces and the users visual sense, the body surface is divided and created, how to show modification method is suggesting, and so is how to transform from the modification of surfaces to
9、the modification of curves. But the current theory of B-Spline curves for modification can not satisfy the users need. Through applying “the least energy for curve modification” to the modification for B- Spline, the method of “the Partial Modification Algorithm for B-Spline” is shown. Firstly, acco
10、rding to the users data, three points in different color is shown on the B-Spline curve, which represent the modification range, the point needing modification. Secondly, the target position of the modified上海交通大学硕士学位论文 ABSTRACT第 IV 页point is necessary. Last but not least, a new B-Spline is present t
11、hrough this method. This algorithm is used to create and modify the body surface in UG. “The Improved Partial Modification Algorithm for B-Spline” can give a better solution to the partial curves. In order to be vivid and visual, the message-send system in windows programming and the use of Windows
12、API functions is employed in the sketch curve modification. Particularly, some description is shown for symmetric figure. In this paper, as to the update between the surfaces, the concept of “the related parameter” is advised to represent the constrainter between two surfaces. The principle and sign
13、ificant element of how to choose “the related parameter” are also included in this paper, such as the unicity of “the related parameter”, how to deal with the related parameter related to several surfaces and so on. In order to make this parametric method more widely used, the assemble design, a fur
14、ther research about the modular and parametric design, is also seen in this paper. In details, it has some information about how to divide the automotive body into piece based on their function, how to add the component into the assemble part, etc. In the end, the dynamic link library, which is buil
15、t in Visual C+, is added closely into the UG environment as a result of UG application development. All in all, the parametric design reduces the requests of the designers for design experience and theory, Computer Graphics and the operation of CAD software. It also makes the design and modification of automotive body faster, easier and laborsaving.KEY WORDS: the parametric design, the design of automotive body, the partial modification algorithm for B-Spline, the related parameter, UG modularization design上海交通大学硕士学位论文
