Key Technologies Research On Reverse Engineering Of Supercharger Impellers

Reverse Engineering (RE), which is applied to develop new products and to introduce advanced technologies, has received most attention both from academia and industry. With the development of RE, its industry applications for common parts are quite consummate. Recently, notable efforts have been made toward Reverse Engineering on complex parts with quality and efficiency. The major objective of this research is to realize rapid digitization, accurate surface reconstruction and perfect surface quality of the engine supercharger impeller.Digitization strategies of complex parts like an impeller are studied, so accurate, efficient, secure digitization is realized in this thesis. The structure of the impeller in engine supercharger, firstly, is systemically analyzed. A series of digitization strategies including equipment selection, stumbling block avoidance, registration, rotation axes computation and borderline measurement are presented. Secondly, based on the structure of the impeller, a GA-Based the Multi-Character Inspection Path Planning on CMM is proposed. Finally, digitization of the impeller is realized.Data pre-processing technologies such as singular points elimination, registration and radius compensation are studied. Base on chord high difference algorithm, a new one called chord high difference-ratio algorithm is proposed to improve veracity and robusticity of singular points elimination. Then, a registration algorithm based on local surface reconstruction is proposed, which avoids infaust influence coming from single reference point error. Furthermore, error of registration is accurately calculated. A new radius compensation algorithm based on Delaunay triangulation is presented, which can improve calculation efficiency and veracity of compensation vector.Wavelet fairing technology is studied and introduced into fair Quadi-Uniform Cubic B-Spline curve and surface with arbitrary number of vertexes. Based on B-spline theory and its properties, a decomposition and reconstruction algorithm of semi-orthogonal B-spline wavelets is presented by strict mathematical deduction. Because of its limitation to vertex number, an arbitrary resolution wavelet decomposition and reconstruction algorithm is proposed and applied to curve and surface fairing. This technology can also be used to control precision when curve and surface are faired and achieves best combination between quality and precision. Consequently, the supercharger impeller functionality...