Data Pre-processing And Model Modifying For Reverse Engineering

Reverse engineering (RE) is a reversed design process (from physical model to electronic data to product) compare with the normal design process (from idea to drawing to product). RE technology can shorten the product development period and help enterprise to improve competitive ability in market. Based on the detailed analysis for the model reconstruction process, author did some research on the IGES file from ROMER CMM, scanned cloud points processing, CAD model reconstructing as well as its modifying. The main research work is as follows:(1) The graphics data exchange standard is the American standard— Initial Graphics Exchange Specification(IGES). Most of CMM and CAD software support the IGES files' import and export operation. The IGES file framework, record data form and entity definition form were all studied here. The interface software was programmed, which could read and write IGES file, and exchange data among this software, CMM and common commercial CAD software.(2) There are many noise and/or redundancy points in measured cloud points. These points bring the problem of enlarging cloud points. Moreover, some of them affect the accuracy of reconstructed model. The author analyzed the eliminating points techniques, filtering points techniques, reducing points techniques for processing these points. Using method of measuing angle to eliminate error points, using averaging method to filter points and using span method to reduce points, these in the cloud points pre-processing, which could pre-process points for sectional cloud points.(3) There are some errors between reconstructed model by RE and original model. The author analyzed the error resources for reversed model and presented symmetric model modifying, assemblage model based modifying, limited drawing based modifying and specimen model based modifying.These four...