关键词: 模型重建, 飞机外形, 飞机结构件, 特征分解, k近邻, 直纹面, 曲面形状修改

Abstract: A feature-based model reconstruction strategy of aircraft contours and structural parts is discussed systematically in this article, and the definition of infrastructural surfaces and solid features is given. The proposed method enables rapid CAD model reconstruction with comprehensive feature representation, which is beneficial to design improvement or modification. A spatial sphere algorithm by gradually widening the search range is developed for searching the knearest neighbors of a measured point in a massive scattered point set, which improves the search efficiency greatly. Then, an approach to rebuild the surface feature of a structural part conjoint with the aircraft contour is proposed. That is, if the surface feature conjoins a skin with a narrow area, it is approximated by a ruled surface; otherwise it is deduced by offsetting the aircraft contour. Surface shape modification based on engineering constraints is also investigated, and a smooth surface satisfying a given point, curve, and surface constraints can be derived by minimizing the bending energy of the different surfaces between pre and post-shape modification. Also the expressions of the bending energy and curve constraint for a B-spline surface are given. Finally, model reconstruction of a certain wing rib is provided to illustrate the validity of the proposed method.

Key words: model reconstruction, aircraft contour, aircraft structural part, feature decomposition, knearest neighbor, ruled surface, surface shape modification