Abstract:TSP art is an art form for drawing an image using piecewise-continuous line segments with no crossings. This paper presents a multi-color robotic pen drawing system capable of drawing complicated TSP pen art on a planar surface. Given a colored, raster image, we first convert it into a set of points representing the original image's tone by controlling the density of the points. Then, we find a piecewise-continuous linear path that visits every point exactly once, equivalent to solving a Traveling Salesman Problem (TSP). Our robotic drawing system consisting of single or dual manipulators with fingered grippers and a mobile platform, performs the drawing task by following the resulting complex and sophisticated path composed of thousands of TSP sites. As a result, our system can draw a complicated and visually-pleasing TSP pen art with high accuracy and efficiency. We also demonstrate that our system can draw a TSP pen art on a large wall, which is very hard for a human artist to achieve.