Research On Automatic Reverse Engineering Techniques Based On CMM

Reverse Engineering is the technology that analyzing, comprehending and redesigning products on the basis of the existing products. It has been widely used in the domain of automotive, mechanical, aviation, home appliances, communication, national defense and so on for shorting products development cycle, high efficiency and low cost. For the request of the increasingly competitive market, techniques of Reverse Engineering developed unprecedented; however, Reverse Engineering modeling methods currently achieved by manually modifying CAD-model interactively, which got low efficiency relatively; the modeling accuracy was relyed on the modeling experience of operator's, and it was difficult to construct complex models.The idea of Automatic Reverse Engineering was brought forward, which reduced the requirements of modeling experience, constructed surface more efficient and especially got a more accuracy model. Its main idea was converting triangular meshes which could be easily got automatically and could express arbitrarily complex models into quadrilateral meshes, and constructing NURBS surface that had the capacity to represent arbitrarily curved surface in high quality in quadrilateral meshes, then splicing NURBS surfaces into an entire surface at the end.Focus on the idea of Automatic Reverse Engineering Technology, the main research contents and conclusions were as follows:1. Data Measurement. Studied the methods of CMM measurement, got the point clouds of Golf Club Head, and verified the reliability of point clouds we had got after analyzing the principle of generating deviation. For the point clouds of poor quality, improved its CAD model and re-measuring, and gained reliable data.2. Data preprocessing. Corresponding Point Matching Method was adopted to align Multi-view point clouds, and an algorithm of Unit-Point-Vector was designed to remove noises and gained good effect.3. Automatic constructing triangular surface and mesh simplification based on dihedral angle. Surface with triangular meshes was constructed automatically through doing preprocessing for scattered point-cloud, doing post-processing for Delaunay triangulation of space based on investigating the principle of Delaunay triangulation, and extracting model surface. An algorithm of triangle mesh simplification based on dihedral angle was proposed by studying the Garland's mesh simplification algorithm, and it efficient kept the shape features of model.4. Data segmenttation based on Morse theory. Morse theory was applied in Reverse Engineering and Morse-Smale complex was extracted on the triangular surface in order to construct quadrilateral meshes. The method of Laplacian Spectral Analysis was adopted to construct discrete Morse on the triangular surface. Data segmentation could be complied automatically according to quadrilateral meshes needed doing grids optimization which was researched.5. Surface construction and Automatic Reverse Engineering System design. The parameters of rectangular grids was gained by transforming of space and triangular interpolation based on studying surface constructing theory, and an entire surface of the model composed of pieces of NURBS surface was got. On the GUI platform of Matlab, an Automatic Reverse Engineering System was established for using conveniently.Automatic Reverse Engineering Technology was almost achieved by learning and researching on the related technologies of Reverse Engineering following the main idea of it.