Scientists Are Developing Stair-climbing Wheelchairs

Visiting friends, going shopping, taking part in events: Mobility is the prerequisite for a self-determined life. People who are mobile also do not need to be cared for and cared for. However, it is often difficult for paralyzed people to even leave the house without help. "Very few houses in which older people live have lifts," explains Prof. Bernhard Wolf from the Heinz Nixdorf Chair at TUM.

Stable thanks to the principle of the inverse pendulum

It quickly became clear to the scientists: a wheelchair had to be developed that could climb stairs. It should also be agile and slim. The researchers therefore limited the running gear to one axle. In contrast to two-axle wheelchair undercarriages, for example, movements forwards, backwards and rotations around its own axis can be carried out almost simultaneously. The wheelchair maintains itself according to the principle of the inverse pendulum. "Every small change in position is recognized and immediately compensated by the drive," says Wolf.

Picture gallery

Picture gallery with 5 pictures

Wheelchairs also manage narrow stairs

But how should the wheelchair overcome the stairs? Previous concepts used caterpillars or castors. "But these wheelchairs have to be operated," explains Wolf. This means that another person has to be careful that the chair does not tip over. The wheelchairs also have a large turning circle - they cannot cope with narrow stairwells.

Bionic concept with upper and lower legs

The scientists opted for a bionic concept. Two feet, which are composed of human thighs and lower legs, are attached to the wheelchair. If the chassis ultrasonic sensors detect the stairs, the wheelchair drives backwards up the stairs until the two wheels touch the first step. Then the "feet" extend, whereby the wheelchair lifts. With the help of electric motors, the legs push the wheelchair to the next higher level. The camera system ensures that the wheelchair is on the step and not on the edge.

Wheelchair also goes down stairs

This technology can also be used to climb very narrow stairs - with the exception of spiral stairs. Then the legs retract and the undercarriage switches back to driving mode. The wheelchair can also go down stairs.

Comprehensive mobility concept

Using a prototype, the engineers were able to show that their principle worked. However, the concept goes beyond climbing stairs. "We want people with wheelchairs to have a real mobility replacement," says Wolf. For example, it could be used as a car seat. So it would not always have to be folded up and stowed in the trunk. It would also not be necessary for the user to have to lift himself from the car seat back onto the wheelchair. Since it has an internal drive, it is narrower than a standard wheelchair.

Industrial partners wanted

However, the possible industrial partners are still cautious. "I think the reason is that the principle is technically a bit complex and then of course there are already standardized wheelchairs." Wolf is convinced that the demand for the bionic wheelchair would certainly be high - because although it would cost more than a standard wheelchair, it also offers its users the opportunity to move more freely. (mz)