Granular universal gripper.

10 November 2010

One of the trickiest things in the field of robotic engineering is getting the manipulators right. Look down at your hand: you probably have five digits, four fingers and a thumb which are articulated and largely independent of one another (modulo a bit of funny business with the ring and little fingers but, as with many things natural variation comes into play here). Each finger folds and rotates in ways that the science of engineering hasn't quite gotten the hang of replicating. Then a group of scientists discovered an insanely simple design: a small sack full of granules and a vacuum pump. When you fill a flexible pouch with small grains of some kind (like coffee gounds or little plastic pellets) the airspaces in between each grain give the pouch as a whole a surprising amount of flexibility. If you then push something against the surface, it'll deform because the contents of the pouch will shift to try to surround the object. The researchers discovered that if you suck the air out of the pouch the grains inside will lock in place around whatever you pressed against it and you can move it around. If you want see a demonstration of this phenomenon take a look at this homebrew version someone made with ground coffee and a balloon. Granted there are some things that a manipulator like this can't lock onto (like cotton balls) and there is probably a lower practical limit on the size of objects a universal gripper of a particular kind could grab (but I can think of a few ways around this) but when it comes to picking stuff up and moving it around this is easily the best I've seen in many a year. I think this could become a popular design among hobbyists once someone figures out a good, tiny electrical air pump that can be incorporated into robotics project (one commenter mentioned using a breast pump for this, which I think might actually have some potential).