A New Method for Generating Work Piece Surface Representations for Robotic Machining

Execution of automatically generated programs for accurate robotic machining requires the generated trajectories to be not only accurate with respect to the work piece, but also that the trajectories are continuous differentiable (C¹) while avoiding unnecessary large curvatures leading to large accelerations that could compromise machining quality or speed. A widely used work piece representation is 3D triangle meshes as they can be easily generated in any CAD representations and from surface scans, and they are also very suitable for robotics applications. However, they lack the C¹ property across the triangle edges.In this paper, a new method for generating C¹ surfaces based on 3D triangle meshes is presented. It will be shown by an example that the method is as good as existing methods with respect to the accuracy of the generated surface, and that the problem with large curvatures is much smaller than for existing methods. Moreover, the difficult input specification of derivatives at the vertices is avoided with this method.