Robot Drawing Techniques for Contoured Surface Using an Automated Sketching Platform

This paper presents techniques for robot drawing on a contoured (2.5D) surface and their implementation using a 3-DOF robotic sketching platform. The related algorithms include pen tip trajectory generation from given digital image and point projection on a contoured surface. The trajectory generation is conducted with existing digital image operations which include erosion, filling, boundary extraction, skeleton estimation and line segment sequencing. Further translating the pen tip coordinates based on model geometry, automated robot drawing can be practically achieved. The work includes discussion and analysis of the drawing mechanism of the sketching platform, as well as experiments conducted to show the performance of automated drawing on flat and contoured surfaces. This paper also proposes improvements to enhance the compatibility of the robotic sketching platform to eventually achieve 3D surface drawing.