For many people with walking disabilities all over the world, everyday life is filled with barriers. They cannot overcome obstacles such as curbs or stairs, and they often have to take long detours to avoid them.
However, a group of Swiss students plans to change all of this. Engineers at the Swiss Federal Institute of Technology in Zurich (ETHZ) collaborated with designers from the Zurich University of the Arts (ZHdK) to develop a new type of wheelchair that they call the Scewo (stair-climbing electric wheelchair). The chair is electrically driven, moves on two wheels like a Segway, and is able to climb stairs using small caterpillar tracks.
One step per second
This is how it works: The wheelchair user approaches the stairs and selects the appropriate function on the touchscreen. The chair measure the incline with sensors and cameras before automatically backing up to the foot of the stairs. The caterpillars are lowered. They begin to turn, and the wheelchair climbs the stairs, moving at a rate of one step per second. The wheelchair user always remains in a level position. When the sensors detect the last step, the stabilizing wheels fold out to prevent the wheelchair from tipping over. The caterpillars are raised, and the wheelchair user can continue traveling on two wheels.
The wheels and caterpillars are driven by two maxon electric motors. These are brushless DC motors combined with ceramic gearheads. Ceramic is always a good choice when high forces act on the components, yet the gearhead has to be very durable. The Scewo team is very pleased with the drives that maxon has supplied. As Pascal Buholzer explains: “The combination of motor and gearhead is robust, precise, quiet and, at 3.2 kg, relatively light. The maxon engineers gave us expert advice, and the support was excellent.”
Available in 2018 at the earliest
The team presented the first prototype of the wheelchair in the summer of 2015. Now they are overhauling it with the aim of winning the Cybathlon in fall, 2016, an event where disabled people compete against each other using technical aids. At a later date, when all the students have completed their degrees, the team plans to found a start-up and to introduce the wheelchair to the market with all its essential functions and, most importantly, at an affordable price.
The initial feedback from disabled people all over the world has been very positive. The roll-out video on YouTube has received more than two million views. "We are getting inquiries almost everyday from disabled people and potential investors," says Pascal Buholzer. For the time being, only one person will be using the Scalevo wheelchair: the competitor who will be taking part in the Cybathlon. However, in a few years this means of transport could be a common sight on our streets.