UV Grid Generation on 3D Freeform Surfaces for Constrained Robotic Coverage Path Planning

Abstract

There are many industrial robotic applications which require a manipulator’s end-effector to fully cover a 3D surface region in a constrained motion, such as painting, spray coating, abrasive blasting, polishing, shotcreting, etc. The manipulator must satisfy surface task constraints imposed on the end-effector while maintaining manipulator joint constraints. Coverage path planning (CPP) in this context generally involves placing commonly used coverage patterns (such as raster, spiral, or dual-spiral) onto the surface. There is substantial research for CPP on 2D surfaces, however, the problem of generating surface task constraints and evenly spaced coverage paths becomes particularly difficult when considering 3D freeform surfaces. Previous research concerning CPP on 3D surfaces consider parametric surfaces with limited surface curvature or produce unevenly spaced coverage paths. In this paper, we introduce a novel method to generate a uv grid on a 3D freeform surface (represented as a 3D polygon mesh) to facilitate feasibility checking for constrained coverage motion under task and manipulator constraints and to significantly ease the creation of more evenly spaced coverage paths for optimal application of task requirements. We applied our method to example 3D freeform surfaces to demonstrate its effectiveness.