A Study On Reconstruction Technology Of Tortuous Sculptured Surfaces From Scattered Data Points

Aviation industry is an indicator of the scientific-technical level and defenseability of a county. The Communist Party of China and China Government pay greatattention to large aircrafts. A special project with huge investment for developinglarge aircrafts with emphasis on aircraft engines has been established. The measuringprocess of turbine blade discs largely determines the carrying capacity, endurance,acceleration and improves the dynamic performance of the aircraft greatly. Innowadays most blade discs and turbine blades are twisted complex free-form surfaceparts, which increase the difficulty of machining and measuring process. This paperaims at realizing the error evaluation of turbine blade measurement through studyingthe twisted surface reconstruction technology. In this paper, Surface reconstruction isrealized by using NURBS technology, to solve the scattered data points of surfacereconstruction technology, and the optimization analysis was carried out on thereconstruction accuracy. In this paper, NURBS technology is used, and the majorefforts will be aimed at the surface reconstruction with scattered data points, what’smore, the optimization analysis is carried out on the reconstruction accuracy.The main research of the paper contents:1、 Through analyzing and comparing the surface reconstruction methods, combinedwith the actual measured blade geometry feature, the method using NURBSleast-square fitting technology to reconstructed surface of measurement datapoints is given.2、 Some basic theories related with NURBS surface reconstruction are introduced.The important parameters of NURBS surface reconstruction are listed includingparameterization, node vector, basis function, the geometric meaning of thecontrol points and the solving process. The common free-form surfacereconstruction can be realized with measurement data points.3、 The method of surface reconstruction of scattered data points is put forwarded.Structuring matrix sequence and knot insertion are the two basic ideas aboutsurface reconstruction of scattered data points. Summarizing the two basic ideas,the paper points out the key to the reconstruction of scattered data points isachieving the uniform node vector, and in this paper the surface reconstruction of scattered data points is successfully implemented with the method combininginterpolation and average node vector.4、 Precision analysis about the surface reconstruction is carried out. After beenanalyzed, the deviation of reconstruction can be converted to solving the datapoint’s projection on the reconstructed surface. The higher order nonlinearequations can be solved by establishing mathematical model, adopting Newtoniteration. And through surface geometric segmentation the initial value of theNewton iteration can also be obtained. And in this paper the method aboutprojection of edge data points and vertexes data points is also given.5、 Through computer simulation for measuring data points. The data points can begained through computer simulation, and they can also be obtained by using UGto establish three-dimensional model then utilizing UG/Open Grip to measure themodel. All of the two methods are easy to implement the feasibility analysis ofthe algorithm.