For the frame they decided to make it very light, so they bought “Balsa-Holz” and cut the geometries (layer for layer) on the laser cutter. After assembling all the layers they inserted polystyrol in the inside for mounting the electrical devices. It also rose the electrical system a bit, by means if the inside would get wet, the electric should be save. The axles were made out of aluminium rods and glued into the wheels. To make the whole frame waterproof, they covered the inside with more glue and put some cellular rubber at the “wheel bearings”. To have a special design, they also build a chassis that looked like an origami boat. It was made out of hard foam and covered with paper.
After having some troubles with the software at first, they did some improvements on the wheels (more friction) and tested it again outside on the concrete. It worked nearly perfectly. 😉