Automated inspection planning of freeform surfaces for manufacturing applications

Automated inspection planning of freeform surfaces is a requirement to promote the efficiency and automation level of online inspection system and the quality of scanned data. This paper proposes a new approach and algorithms for the inspection planning of freeform surfaces. Given the CAD model of a measured surface as an input the approach first uses a search-based planning algorithm to determine the locations of the sample curves extracted from the CAD model automatically for inspection path planning. Then, these sample curves are fitted to construct a substitute geometry of the CAD surface. To guarantee the accuracy of generated scan plan, the deviation between the substitute geometry and the surface of its CAD model are verified using search-based planning algorithm developed in this paper. Once these sample curves are verified, the coordinate of the generated inspection paths is transformed into the global coordinate system. In practice, the coordinate of the inspection paths needs to be transformed into the machine coordinate system. To accomplish this task the acquired real state information is applied. Experimental results on inspection path planning of a variety of the machined metal skin of aircraft are reported to show the validity of the proposed methodology.