A Robot With Beanbag Hands Learns the Gentle Touch

By Andrew Moseman | October 25, 2010 4:16 pm

The simple act of picking something up requires a plethora of decisions: Is the thing light or heavy? How much force do I need to grip it? If I grip too hard, will I crush it with the might of my mighty hands?

As we grow up we become fairly practiced at the art of picking up (objects, that is), so our brains will do most of this for us without a lot of conscious thought. But all those variables—plus adapting to a surprise on the fly—mean that picking things up with the proper force is one of the most difficult skills to teach a robot. That’s why the design by Eric Brown’s team is so clever.

In this week’s Proceedings of the National Academy of Sciences, Brown and colleagues demonstrate (paper in press) their “universal gripper,” a successful prototype of a robot hand. It’s based on an idea that’s been around for a while, and it looks like a beanbag on a robot arm, because, well, that’s kind of what it is.

“Our gripper is simpler because it does not need tactile sensing,” says [Brown]. His team has created a robot hand that is simply a rubber bag filled to about 80 per cent of its volume with glass spheres, each 100 micrometres in diameter. [New Scientist]

A beanbag typically grips our bodies when we’re being lazy, but the advanced version created by Brown’s team (which includes scientists from DARPA and iRobot, the Roomba inventors) can squeeze those glass spheres simply uses coffee grounds inside a balloon that can squeeze around a host of different objects.

The gripper is placed over objects, deforming around them. The air in the bag containing the granules is then removed by suction, causing the granules to pack tightly together – known as jamming – and the hand to grip on to the object. No computation is required, although at present a researcher must decide when to evacuate the air, and the gripper is able to lift a diverse selection of objects, from a car’s shock absorber to a raw egg. The hand is even capable of lifting and pouring a glass of water, or of picking up a pen and using it to draw. [Nature]

But will the simple universal gripper win out over robotic hand designs that feature human-like fingers?

The moldable gripper can function without needing sophisticated artificial intelligence software. Fingered robotic hands may be more suitable for manipulating objects but require “a central processor or brain for a multitude of decisions, many of which have to be made before the hand even touches the object, for example about how wide to spread the fingers apart,” according to the researchers. [Scientific American]

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Video: Brown et. al.

MORE ABOUT: hands, PNAS, robots, senses, touch
  • bigjohn756

    Is this a robot or a remote control device?

  • MT-LA

    I see the “universal gripper vs. robot hand design” to be a false dichotomy. How about an arm equipped with the uni-gripper for picking up objects and simple re-orientation, and another arm equipped with something with more dexterity to do manipulation.

    This particular universal gripper design may also be susceptible to sharp objects..anything that can pierce the bag and compromise the vacuum. This adds further limitations. I’m not discounting the breakthrough though…this will surely find its onto industrial robots.

    @bigjohn: This is a robot designed to pick up remote controls

  • http://discovermagazine.com Andrew Moseman

    @MT-LA good point. I’d be intrigued to see the two technologies combined.

  • bigjohn756

    @2 MT-LA — Can it also change channels?

  • MT-LA

    @bigjohn: No, but it will gleefully reprogram your DVR and then claim that it was your roommate.

  • OldBioEngineeer

    I wrote my PhD thesis in 1974 about the development of an artificial hand, and we were using this deformable grip with glass beads in a non-stretch membrane back then. I hope the use on a robot now is not being claimed as something new !!!

  • http://blogs.discovermagazine.com/80beats/ Eliza Strickland

    @ OldBioEngineer:

    Nope, the researchers aren’t claiming that this is brand new. From the post: “It’s based on an idea that’s been around for a while…”

    But I didn’t realize that “a while” meant several decades. Thanks for sharing your experience.

    — Eliza, DISCOVER online news editor

  • http://www.hizook.com Travis

    Colin Angle (iRobot CEO) showed the “jamming gripper” prototype in his 2009 TEDMED talk as an extension of “jamming skin locomotion” (blob robot). In his talk, he showed a video of it grasping medication, keys, a water bottle, and even a dummy-patient’s arm; he also demonstrated a hand-held version. It’s nice to see a more formal evaluation.

    @OldBioEngineer: It’s definitely not a new idea. Recall those “Vac-Man” toys from the 1990’s used the exact same concept. I’d be curious to read through your thesis. Ping me over on Hizook.com

  • http://www.aschoonerofscience.com Captain Skellett

    I think New Scientist have it wrong – in the journal article it says the material used was ground coffee, not glass beads.

  • http://discovermagazine.com Andrew Moseman

    @Captain Skellett
    Thanks for the tip. Indeed, they used coffee grounds in this test of the device. Fixed.

  • http://Discover artistic1

    More importantly will I finally be able to win something at the claw machine?! Those stuffed animals are lodged in pretty tight and it’s hard to pull them apart.

    Seriously though, this could be a very useful device in a surgical setting for supplying instruments to the surgeon in a sterile way, multiple “hands” working at the same time with no concern of collisions or hesitations.

  • http://www.convertiblesofaoutlet.com/halo-woven-convertible-sofa-bed-dh.html halo

    Thanks this manufactured for interesting reading. I really like your wordpress theme,I keep coming again here and that i dont know why. I just seriously like your web site lol… I just study something much like this on an additional web site. I think they may well of stolen your blog?


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