On-line 3-D inspection of deformable parts using FEM trained radial basis functions

Usually, the inspection of manufactured parts in industry is done by performing a comparison between a reference model, such as a CAD model, and 3-D measurements taken on the surface of the part using systems like coordinate measuring machines, photogrammetry, or laser scanners. This process involves first the alignment of both reference models and measured dataset to determine if the part fulfill the required tolerances specified by the designer. However, due to new flexible materials as well as structural shape many parts are remarkably flexible. In those cases, it is necessary to carry out a fixturing process in order to constrain the part to its nominal shape. This fixturing process is time consuming and hard to automate. This paper presents a new method for the alignment of deformable parts that do not require any fixturing step. The proposed approach uses a finite element method to obtain a physical deformation of the original CAD model, and radial basis functions to approximate this deformation faster and in real-time, opening the door to on-line inspection of deformable parts. Experimental data are presented.