RESEARCH ON A METHOD OF EXTRACTING GROUP SURFACES FEATURE IN DISCRETE DATA ENVIRONMENT

The group surfaces (GS) is the important part of geometric features design. The machining quality of GS has important influence on the assembly and working performance of parts. The complete data transfer between CAD system... [ view full abstract ]

The group surfaces (GS) is the important part of geometric features design. The machining quality of GS has important influence on the assembly and working performance of parts. The complete data transfer between CAD system and the Computer Aided Quality (CAQ) system and the intelligent measurement planning have meet difficulties for lacking of the method of extracting GS feature and parameter in discrete data environment. This paper describes a method to extract the GS feature and the parameters with using the differential geometric properties of the discrete data vertexes. The Euclidean distance-curvature expression matrix of surface and the metric method of diversity between matrixes are constructed. The transformation parameters are extracted with the iterative nearest point (ICP) algorithm. The 3D model retrieval is used to extract the GS feature and the parameters. The models of spiral bevel gears were taken as calculation examples. It is shown from the examples that the extraction of the GS feature which is composed of complex surfaces and the parameters can be achieved effectively with the proposed method. The field application of the automatic CAQ system can be spread with the proposed method to improve the efficiency and accuracy of the machining quality inspection.