Robots extend the extra strong arm of friendship

Robots were always meant to lend a helping hand: and this one does, literally. It is a robot prosthetic hand strong enough to hold a weight equivalent to four kilogram bags of sugar, which is self-contained apart from batteries and two printed circuit boards.

Built by a team at the Nuffield Orthopaedic Centre and the engineering science department at Oxford University, the hand is intended to replace a human one and is operated by sensing the movement of the muscles in the user's forearm.

"The most important thing about a prosthetic is that it should be more like a pair of glasses than a hip replacement," said Peter Kyberd, who helped develop the hand over the past three years.

"It should be something you put on in the morning and just wear, that you don't need training to use."

He is shown here operating the hand at the Robotix show in Glasgow's McLellan Galleries, where a huge variety of robots are on show for the next three days.

A number of amputees in the Oxfordshire area have already tried prototype versions of the hand, developed at a cost of pounds 127,000. Dr Kyberd thinks that, for the moment, it is more effective to operate it via the muscles than by techniques requiring surgery, such as a direct attachment to the nerves that were linked to the hand.

"Nerve attachment would be a huge invasion," he said. "This is better in that it just uses surface attachment: you tense muscles to close and open it, and to touch and to squeeze. If it feels that what it is touching is slipping, it will squeeze tighter."

The maximum that the hand can squeeze is roughly 4.5 kilograms. A normal hand can manage more than 10 times that amount - a range which Dr Kyberd says would be feasible for a robot hand, "though it would run the batteries down faster".