Fast dimensional inspection of deformable parts from partial views

One of the conventional ways to inspect deformable parts is to compare a data model against its nominal CAD model. This process assumes that the data model includes most of the visible surface including regions around fixation points where the part will be attached to others. This paper proposes a method to inspect deformable part by acquiring only regions that need to be inspected and then by applying to the CAD model a non-linear deformation using FEM modeling to minimize the differences with the partial views. The process first starts with a rigid alignment followed by an iterative process where the part's deformation is iteratively matched to the partial views. In this scheme, fixation points are not digitized and the non-linear part deformation calculations are estimated by interpolation. Test results performed on real parts compares favorably to deformation calculations using complete data model from the point-of-view of speed and accuracy.