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Robotic gripper picks up objects using coffee grounds and a balloon (UPDATED: new video)

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October 25, 2010

The universal gripper writing with a pen (Image: John Amend, Cornell University)

The universal gripper writing with a pen (Image: John Amend, Cornell University)

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While creating robotic grippers to pick up objects that are all the same shape and consistency is relatively easy, difficulties arise when trying to create one versatile enough to handle a wider variety of objects. The flexibility of the human hand has led many robotics researchers to borrow the familiar four finger and opposable thumb template that has served us so well, but getting the robotic hand to exert enough force to grip a variety of objects without breaking the more fragile ones is still a difficult task. For this reason a team of researchers has bypassed the traditional human hand and fingers design to create a versatile gripper using everyday coffee grounds and a latex party balloon.

Called the universal gripper, instead of being designed to pick up a particular object the device conforms to the object it is grabbing. The gripper, which is attached to a robotic arm, consists of an everyday party balloon filled with ground coffee. The coffee-filled balloon presses down and deforms around the object to be picked up, and then a vacuum sucks the air out of the balloon to solidify the grip on the object. When the vacuum is released, the balloon becomes soft again and the gripper lets go of the object.

The universal gripper is made from a party balloon filled with coffee grounds (Image: John...

The gripper is able to form a solid grip because the coffee is a particulate material made up of large aggregates of individually solid particles. Particulate materials have a so-called jamming transition, which turns their behavior from fluid-like to solid-like when the particles can no longer slide past each other. This phenomenon would be recognizable to coffee drinkers familiar with vacuum-packed coffee, which is hard as a brick until the package is unsealed.

As Cornell researcher Hod Lipson explains, “the ground coffee grains are like lots of small gears. When they are not pressed together they can roll over each other and flow. When they are pressed together just a little bit, the teeth interlock, and they become solid."

In principle, any particulate material that can jam will do and early prototypes involved rice, couscous and ground-up tires. Coffee was chosen because it is light and also jams well. Although sand was found to jam better than coffee, it was prohibitively heavy.

The researchers say that the jamming-based gripper’s good performance with almost any object, including a raw egg or a coin – both of which are notoriously difficult for traditional robotic grippers – are what sets the device apart from other grippers. They say this versatility will make it useful in situations where a robot needs to grip or pick up a wide variety of items, including items it may never have encountered before.

The research that led to the creation of the gripper was a collaboration between the University of Chicago, Cornell University, and iRobot Corporation. In the short term the team plans to further develop the gripper with a long term view of applying jamming in a more general way to adaptive robots and structures that might reconfigure, locomote, or recover from damage.

The team's research appears online in online in Proceedings of the National Academy of Sciences.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
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4 Comments

One of that "why i have not invented it myselft" ;-)

I just see some problems oposit to a hand (or similar) - imho it is not able to take the items in not-straight position (imagine the pen not laying or staying, but e.g. 30 degrees in X/Y/Z axis), and it need a lot of space around (imagine 100 pens or more practical - medicine tubes staying close to each other).

But even the hand is not practical for all items/shapes/sizes).

I wonder that maybe the best would be a "hand" combined from "palm" from this bag and "fingers" (with maybe small bags on the ends of the "fingers", which could be used for smaller objects) - this could decrease dramaticaly the needed vacuming power but increasing the resulting gripping strength for all objects (some inteligence to guess what griping type would be best is needed, e.g. starting from the lightest grip, so you will not break egg, and increase or add fingers when needed more)

Tomáš Kapler
26th October, 2010 @ 12:20 pm PDT

@Toma: thank you for the great idea. I just submitted a patent application based on your it. I'll send you couple bucks when I'm rich.

Matt Rings
26th October, 2010 @ 06:04 pm PDT

@Matt: Thank you for writing the application. I used my recently invented transporter to transport a copy of it to my house and then used my recently invented time machine to submit it two weeks ago. I'll send you a couple of gold dubloons from my next trip.

show me
29th October, 2010 @ 09:11 am PDT

Very clever. You can expect to see a lot of low cost solutions to robotic grasping in the coming years. DARPA is financing an important initiative that should change the way we look at grippers:

http://spectrum.ieee.org/automaton/robotics/robotics-software/darpa-arm-program

For some tasks where you need to hold firmly the object in a precise position, I think that fingers will be hard to replace. I invite you to look at our approach. More complicated than the bag, but still more simple than the other hands out there. Did you know that about a third of our brain is dedicated to signals and actions that occur with our hands?

http://robotiq.com

Samuel Bouchard
29th November, 2010 @ 07:43 pm PST
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