Research Of The Reverse Engineering Technology Based On NURBS

Reverse engineering design can not only reconstruct the complex free surface model,but also can repair and redesign the existing product efficiently,and has been applied to fields of aerospace,ship, mold design, medical instrument, precision measure of the complicated product, etc.However,due to the reverse engineering is a new research field, there are still some problems to be solved including data processing,surface reconstruction,etc. Based on NURBS,the data processing and curve surface interpolation algorithm of reverse engineering is studied in the dissertation.First,analyzing a variety of data denoising methods,combining with the types of point cloud data collected and NURBS curve surface interpolation,on the basis of high deviation method,according to the theory of normal distribution,an improved chord high deviation denoising method is proposed,which can well retain feature points on the surface(curve) on the basis of meet the efficient denoising.And through the programming to realize data denoising,the method is proven to be correct and feasible.Second,comparative analysis of various data to streamline method, combining with the collected data point cloud type and curved surface interpolation for NURBS curve, determine the reasonable compaction method, and through the programming completed a set of point cloud data.Then,studying the NURBS curve interpolation problems to be solved, analyzing of multiple node vector determination method,combining with the collected data point cloud type,the parameterized treatment plan and the NURBS curve interpolation process are developed.Mainly analyzes the reverse process of cubic NURBS curves,through the programming to realize the curve interpolation of a set of data points.At last,analysis the interpolation of NURBS surface equation, to equivalent deformation of the interpolation of NURBS surface equation, using the method of substitution, to the computation of complex NURBS surface equation into NURBS curve equation of relatively simple quadratic solving process.A new algorithm calculating surface control points is obtained.