The step-walking wheelchair

Published: 14 Jan 2013

Though it is an essential piece of equipment for its users, the traditional wheelchair has one major disadvantage which is its inability to negotiate raised objects like steps and kerbs.

This means that if you lack the considerable upper body strength needed to ‘muscle’ a wheelchair over such an obstacle, you are left either having to seek help or to find an alternative route.

However, mechanical engineers at Japan's Chiba Institute of Technology may now be on the way to providing a workable solution that overcomes this problem – a robot wheelchair that has the capacity to ‘walk up’ steps and to cross uneven and angled surfaces safely and securely.

Not surprisingly, this step-walking wheelchair has been hailed possibly the most significant innovation since the introduction of the first electric wheelchair.

Given the complexity of the task involved, the robot wheelchair is far chunkier than a standard chair and doesn’t have the standard configuration of a large back wheel and smaller front.

Instead, its four wheels are the same size with each mounted at the end of one of two independent axles. Both of these can swivel through ninety degrees so that when all the wheels are aligned the chair can effectively change direction by rotating on the spot.

To work its ‘walking magic’, the robot chair uses sensors to take in information about its immediate surroundings. Then using this data, the wheelchair automatically changes the relative heights of each wheel, lifting each in turn over the obstacle in its path. The user is not involved in this process at all but just keeps the wheelchair heading in the chosen direction using a joystick.

As the wheelchair moves, its seat continually adjusts its position to remain level even when travelling on sloping surfaces.

At this stage of its development, the robot chair is rather slow and awkward in its movements, but in future the Chiba team are looking to improve their prototype by increasing the speed at which it can climb. They are also aiming to create a more streamlined version that will make it easier for the chair to manoeuvre and access tight spaces.

Elsewhere in Japan, a team of engineers at Kyoto University have unveiled another wheelchair design that they are calling a Personal Mobile Vehicle. Unlike the robot chair, this not only has large wheels to go forward and backwards but 32 smaller inner rollers that allow it to travel diagonally. This means that there is no need for the chair to swivel in order to move left or right, a major advantage where space is at a premium.

With a history stretching back 400 years to the first known wheelchair in 1595, the stair climbing wheelchair and its like are heralding a new era of freedom for their users that can only make life easier.


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