Most of the time, assuming nothing’s gone wrong with them, we take our hands so much for granted that it’s easy to forget what remarkable pieces of engineering they are: not only are they precise and sensitive enough to crack an egg or write a signature, but also strong enough to lift a weight or swing a hammer. Such performance has thus far eluded robot hands, but fortunately few tasks require it; the main challenge is dexterity, which is where [Vittorio Lumare]’s low-cost Yeah Hand could help.
The Yeah Hand is mostly 3D-printed and uses five servo motors per hand; like a human hand, it has no actuators within the fingers themselves, instead using fishing-line tendons to transfer motion from the motors. To reduce friction and keep the motors from overheating, each tendon runs through guides made from PTFE Bowden tubes; in tests, the hand ran 800 cycles of opening and closing without even getting close to overheating. The hand can lift up to eight kilograms and apply a maximum grasping force of five kg. For better grip, each finger has silicone grips along the inner surface, which let it hold smooth objects quite steady; to pick up fine objects, the thumbs have thumbnails.
