We've seen tracked wheelchairs before, that are able to take on steep or uneven terrain. For regular surfaces, however, wheels make more sense. That's why a group of students from ETH Zurich and the Zurich University of the Arts are creating the Scalevo electric wheelchair, which features wheels for cruising and tracks for climbing stairs.
When on smooth ground, the Scalevo balances Segway-style on its two wheels – this setup aids in agility, allowing it to make sharp turns. Upon reaching a flight of stairs, however, its twin rubber tracks descend from its undercarriage to carry it over them. In order to keep the user level while this is happening, a set of pistons tilt the chair back relative to the tracks, compensating for the slant of the stairs.
The mechanical and electrical engineering students now have a working prototype and are planning to use it next year in the Cybathlon, an ETH-sponsored race for disabled athletes using assistive devices. There's no word on whether or not they plan on commercializing the technology.
The wheelchair can be seen in use, in the video below. Although it climbs stairs pretty slowly right now, the team hopes to ultimately attain a speed of one step per second.