摘要

如今，科技创新已成为了衡量一个国家综合实力的重要标准。在加入WTO后，面对激烈的市场竞争，中国汽车工业发展迅猛，逐步融入了世界汽车工业体系。要提高在世界汽车工业体系中的地位，中国汽车行业必须获得自主创新的能力。随着经济全球化的发展，中国的汽车行业要生存，必然要从“中国制造”迈向“中国创造”。近些年，国内一些具备一定实力的汽车厂家已经逐渐走上了自主研发道路，尝试自主研发设计新的车型。在汽车设计的过程中，覆盖件的逆向设计至关重要。汽车覆盖件的逆向设计都比较特殊，不仅要满足功能上的要求，还要求做到美观。发动机仓盖外板设计是汽车覆盖件设计的一部分。

基于CATIA软件的 “数字化外形编辑器”模块可以快速、方便地对测量点云进行处理，勾勒出零件原型的轮廓特征线。“快速曲面重建”模块可以在点云上建立并处理特征线，拟合出满足一定要求的曲面，“创成式曲面设计”模块可以在已建立的轮廓特征线及基本曲面上进一步进行处理，生成更高质量的曲面。从而完成汽车发动机仓盖外板的逆向设计。本文对汽车发动机仓盖外板利用三维激光扫描仪进行三维坐标测量得到点云数据，对所得点云数据使用逆向工程软件CATIA进行预处理。包括点云的过滤、修剪、补洞、形成三角网格等；用CATIA软件对其进行逆向曲面重构，得到重构出的发动机仓盖外板曲面；以重构出的曲面为基础，设计出汽车发动机仓盖外板的拉延模具结构外形，在CATIA软件中做出凸模、凹模和压料圈等结构；并对拉延模具进行有关的工艺计算和参数确定。最终，做出汽车发动机仓盖外板的加工动画。

关键词：汽车覆盖件；逆向工程；曲面重构；拉延模具

ABSTRACT

Today, scientific and technological innovation has become an important measure of a country's comprehensive strength. After joining WTO, facing the fierce market competition, the Chinese automobile industry develops rapidly, and gradually melts into the world automobile industry system. In order to improve its position in the world automobile industry, the Chinese auto industry must acquire the ability of independent innovation. With the development of economic globalization, China's auto industry must change from "made in China" to "created in China" if it wants to survive. In recent years, some domestic automobile manufacturers with certain strength have gradually embarked on the road of independent research and development, trying to design new models independently. In the process of car design Reverse design of panels is very important. The reverse design of automobile panels is special, not only to meet the functional requirements, but also to be beautiful. The design of the outer panel of the engine bin cover is a part of the automobile panel design.

The "Digital shape Editor" module based on CATIA software can process the measurement point cloud quickly and conveniently, and draw out the contour feature line of the part prototype. The "fast surface reconstruction" module can set up and process the feature lines on the point cloud and fit the surfaces that meet certain requirements. The "creating surface design" module can be further processed on the established contour feature lines and basic surfaces. Creates higher quality surfaces. In order to complete the reverse design of the outer panel of the car engine bin cover. In this paper, the point cloud data are obtained by using 3D laser scanner to measure the point cloud data on the outer plate of the automobile engine bunker cover, and the point cloud is obtained by using the 3D laser scanner. The data is preprocessed by reverse engineering software CATIA. Including point cloud filtering, pruning, repairing holes, forming triangular meshes, etc. By using CATIA software to reconstruct the reverse surface, the reconstructed outer surface of the engine bin cover can be obtained, and the reconstructed surface is based on the reconstructed surface. The drawing die structure of the outer plate of the automobile engine barn cover is designed, and the punch, die and material ring structure are made in CATIA software, and the process calculation and parameter determination of the drawing die are carried out. Finally, the manufacture animation of the outer panel of the car engine barn cover is made.

Key words: automobile panel; reverse engineering; surface reconstruction; drawing die

第二章发动机仓盖外板点云数据采集及预处理 5

1. 发动机仓盖外板点云数据的采集 5