An accurate 3D edge measurement method for guided precise modification

Abstract

This paper describes an accurate and adaptive edge measurement method for deformed complex components (DCCs). The edges of these components are irregular, spatially gradual curves. Furthermore, measured edges are used to guide precise modification, which requires the measurement to have high accuracy and integrity. The existing methods for edge detection cannot meet the above two requirements for DCCs. The proposed method is based on optimizing the template edge to reduce the errors caused by deformation, which mainly includes two steps: (1) extraction and preprocessing of the edge template; (2) optimizing the sub-edge poses (pose and position). In the first step, an edge template is extracted using a 3D design model and divided based on structural discontinuities. In the second step, the edge is divided into sub-edges, then support regions are adaptively searched for sub-edges and the sub-edge poses are optimized. The sub-edge transition area is interpolated to achieve smoothness of the entire edge. This approach was experimentally validated using DCCs and achieves a higher accuracy than conventional approaches. The experimental results demonstrate that our proposed method performs well in terms of accuracy (0.06 mm) and efficiency (within 85 s), and there is no local missing at the edge.