Cycloidal Toolpath Planning for Robotic Sandblasting
Today, Efecan and I attached the sandblasting device to the robotic arm. The device sprays a special sandblasting material onto surfaces using air pressure. Thus, it is used for cleaning moldy and dirty surfaces in buildings under restoration. Under normal conditions, the sandblasting gun is controlled manually. If the cleaning is too light, it remains insufficient, but it shouldn’t be so intense as to erode the stone either. Normally, the operator performs this control visually. Here, the potential uses for the robotic arm are vast. Today, we built the adapter that connects the small gun to the robot and conducted initial tests. Our work has naturally started bringing up some of my old and beautiful geometry topics again.
Efecan explained that, when an operator performs sandblasting manually, instead of scanning in straight lines, they move in circular patterns along the straight line. Immediately, the cycloid code from 2014 came to my mind. At one point, I had spent quite a bit of time working on the mathematical definitions of cycloid and epicycloid curves. Those codes are, of course, a bit outdated. However, 12 years ago, I had no idea I would use that experience in this job today. Therefore, I quickly created a new cycloid code using the old ones.
This time, the ultimate goal is to generate cycloidal paths on a given surface. In the sandblasting process, it is essential that the gun remain parallel to the surface normal and maintain a fixed distance from the surface. Of course, these are tasks perfectly suited for a robotic arm. After generating cycloid paths on a template curve, I projected them onto the surface. The points obtained by exploding this projection are offset according to the surface normals, constructing the planes where the tip of the gun (TCP) should be located. It looks like our work with the robot will continue for a while. Below, I am sharing the part that generates the cycloids from the given template curves. You can check my previous cycloid experiments here, here, and here.
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