Stairs or kerbs are still a major problem for wheelchair users. Even the most modern applications cannot overcome such obstacles automatically. Instead, patients have to rely on help, use ramps or gain a lot of momentum. "The latter is particularly dangerous for those affected, as they can easily fall out of the wheelchair, injure themselves or be hit by a car," criticizes Rory Cooper, Head of the Human Engineering Research Lab (HERL).

HERL wants to remedy this with the 'MeBot'. The world's largest research laboratory for wheelchairs has developed a robotic system that can automatically negotiate stairs and kerbs. It is based on a base consisting of six wheels arranged in pairs. The middle, larger wheel unit is intended for driving, while the front and rear wheels are used for steering. All three pairs of wheels can move independently of each other in horizontal and vertical directions. As soon as the robot detects an obstacle, the first pair of wheels extends and lifts the vehicle. The middle unit then moves forward independently and lifts the wheelchair over the edge. Finally, the rear pair of wheels is retracted. "With this mechanism, the system can climb obstacles piece by piece, similar to a caterpillar," Cooper explains.

In order for 'MeBot' to safely negotiate kerbs and stairs, expertise in signal acquisition and processing is required. This is where the scientists at Fraunhofer IPA came in. The team led by Bernhard Kleiner, head of the 'Motion Detection and Sensor Function' group, integrated a radar module that detects objects with high precision and activates the automatic mechanism to overcome them. The system measures the stairs or kerb geometrically so that the control unit knows exactly how the wheelchair needs to be positioned in order to approach the obstacle. When the vehicle is parallel to the object, the automatic overcoming mechanism kicks in and the step is climbed. The radar measurement technology was chosen to be independent of environmental influences. Rain, cold, fog or humidity are therefore no problem for the wheelchair.

At the ETH Zurich Cybathlon on October 8 in Kloten (Switzerland), 74 athletes from 25 countries will show how robot technology helps them in everyday life. In contrast to the Paralympic Games, the Cybathlon does not focus on top athletic performance, but rather on the optimal combination of robotic aids suitable for everyday use and their users. With this competition, ETH Zurich aims to draw attention to the difficulties faced by people with physical disabilities and to encourage researchers and developers to develop technologies that really help people with disabilities in their everyday lives.