Max orientation coverage - efficient path planning to avoid collisions in the CNC milling of 3D objects.

Most path planning algorithms for covering a complex 3D object ignore physical limitations or constraints on a robot’s motion. Adhering to such constraints for a given path can slow down the time to cover the path because the motion may need to be adjusted. This work considers a scenario in computer numerical control (CNC) milling applications, where the robot is a cutting tool that needs to cover the surface of a complex 3D object under the following constraint: for every point on the generated path, the robot must be assigned an accessible orientation to avoid collisions between it and other parts of the object. Our proposed approach, which we call max orientation coverage, employs a two-step optimization scheme. It can improve path efficiency with respect to both the length of the path and the cost of dealing with the collision-avoiding constraints. We evaluate our approach through extensive simulation studies on four CAD benchmarks against a state-of-the-art baseline. We show that our proposed approach can improve the efficiency of the path by 29.7% on average compared with the baseline and the improvement goes up to 46.5% for certain complex objects.