曲面修改在逆向工程中的应用研究

Application Research of Surface Modification in Reverse Engineering

针对汽车A-class特征曲线高精度、高光顺性的基本要求,提出了基于控制顶点规范的Bezier曲面迭代微调方法,用曲面反算变换为NURBS曲面,经过基于最小弯曲能曲面修改以后,对进行外形优化。该法核心是控制顶点的微调计算和基于最小弯曲能曲面修改,实现对空间型值点的光顺拟合,实现迭代拟合过程的快速收敛,同时实现了曲面微调和曲面修改的自动化,使基于逆向工程得到的复杂曲面不仅满足精度要求,更可以进行美学设计。结合某汽车的A级曲面的点云数据实例,应用迭代微调有效地提高了生成CAD数据的效率和准确性。

Since the rigid precision control is important, this paper presents a method of Bezier curves minor adjustment which is based on the basic requirements of rigid precision and smoothness on auto class-A surfaces feature curves. This method aims to change surface-count to NURBS surface, and optimize the figures after surface modification of the minimizing bending energy of surfaces. The cores of this method are the minor adjustment calculation of control vertex and the modification of the minimizing bending energy of surfaces. The two factors not only realize the smoothing fitting of the space points and quick convergence of fitting iterative process but also the automatic process of surface minor adjustment. Both of them meet the precision requirement and aesthetic design and the latter is more important. With the example of elass-A points-cloud data of vehicle, the paper shows the availability to improve the efficiency and veracity of building CAD data.