Robotic hand attains sensitivity and strength with coffee grounds and balloons

Here's a fascinating report from the Proceedings of the National Academy of Sciences on a novel kind of robotic gripper that uses balloons and coffee grounds to attain strong, sensitive grips:
Here we demonstrate a completely different approach to a universal gripper. Individual fingers are replaced by a single mass of granular material that, when pressed onto a target object, flows around it and conforms to its shape. Upon application of a vacuum the granular material contracts and hardens quickly to pinch and hold the object without requiring sensory feedback. We find that volume changes of less than 0.5% suffice to grip objects reliably and hold them with forces exceeding many times their weight. We show that the operating principle is the ability of granular materials to transition between an unjammed, deformable state and a jammed state with solid-like rigidity. We delineate three separate mechanisms, friction, suction, and interlocking, that contribute to the gripping force. Using a simple model we relate each of them to the mechanical strength of the jammed state. This advance opens up new possibilities for the design of simple, yet highly adaptive systems that excel at fast gripping of complex objects.

Update: Here's a great video of the hand in action (WMV) -- thanks, Dspin!)

Universal robotic gripper based on the jamming of granular material (via IO9)

(Image: Turkish Coffee grounds - degustation - Ottoman Cuisine, a Creative Commons Attribution Share-Alike (2.0) image from avlxyz's photostream)


  1. This is basically the same technology that was used in a toy when I was a kid, sounds like.

    It was a little humanoid figure made of rubber filled with granules. You’d stretch out its’ limbs freely then evacuate the inside with a pump and it would hold its’ pose until equilibrium was restored.

    I guess somebody else played with one of those, too, and is now making robotics.

    1. I had the same toy, it was called “Vac-Man”, he was the arch-enemy of Stretch Armstrong. If I recall correctly both of them were made from corn products, Armstrong being filled with corn syrup, and Vac-Man with ground corn cob dust.

  2. Sorta like how a vacuum pack of coffee is as hard as a brick until you put a hole in it. Novel application.

  3. This is clearly reverse-engineered Dalek technology.

    Building unstoppable mutant hate machines with cybernetic shells always seems like a good idea at *first*…

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