Engineers from Switzerland and Israel have created a robot for hot cutting shapes complex shapes from polystyrene foam. He keeps both hands heated wire and changes in the process of cutting her bending to cut the surface of complex shape. The article will be presented at SIGGRAPH 2020.
Thermoresin is a simple tool that allows you to quickly cut out Styrofoam pieces of different shapes. It can be used as an alternative to a 3D printer for rapid prototyping or as a tool for full detail. For example, Thermaltake parts used in aeromodelling.
Thermoresin consists of a taut metal wire is heated by electric current, allowing you to melt the polystyrene in contact with him. Moving the wire relative to the piece of Styrofoam, you can control the final shape of the object, but somehow or other it is formed by ruled surfaces, so this tool cannot be used to create concave surfaces, as to create a convex often have to do a lot of slices.
Engineers under the guidance of Steliana of Koros (Stelian Coros) from ETH Zurich have created thermoresin with actively bent during the cutting wire that allows you to create more complex surfaces. So the wire was easy to bend and move, the developers have placed it between the two hands of the robot YuMi. Moving the ends of two manipulators it can not only rotate the wire, but also to change the degree of tension and flexing
Control algorithm the robot receives the desired shape of the object and calculates her trajectory for both manipulators. Trajectories are composed of many discrete curve, by applying an interpolation which is possible to obtain a uniform cut surface. For each slice, the algorithm calculates a set of curves that at the end of the cut as much as possible to reduce the difference between the surface model of the object and the surface of the slice. At each step he calculates the current deviation from the ideal shape and creates a new set of curves to minimise it.