Remember that compliant "jamming" end effector unveiled by Colin Angle (iRobot CEO) at TEDMED 2009? Even then, it was demonstrated picking up medication bottles, keys, and water bottles (a hand-held version was also demonstrated). Well, it just got a whole-lot more official with the publication of "Universal robotic gripper based on the jamming of granular material" in the Proceedings of the National Academy of Sciences (PNAS). The cool thing about this method of grasping is its relative simplicity: a rubber sack (balloon) filled with coffee grounds is pressed onto an object, it conforms to the object's natural contours, and the air is pumped out (a volume change less than 0.5%) to form a stable grasp-- no complex grasp planning required. Be sure to check out the new video and photos!
Update on Oct 28th, 2010: John Amend, co-author of the PNAS article, wrote in to share this updated video with voice-over.
The latest effort is a joint effort between U. Chicago, Cornell, and iRobot. Here is a video of the robot grasping all sorts of objects (eggs, LEDs, tubing, light bulbs, pens, etc.), pouring water, and writing with a pen.
Here is a brief diagram explaining how this method works, directly from the PNAS article.
ScienceMag discusses some of the limitations:
The hand works best on hard, dry, geometrically complex objects like screwdrivers and toy jacks. It has more trouble with flat objects like plastic discs and porous objects like cotton balls, because the air holes weaken the suction. It also can't grip anything bigger than half its size—the biggest items the team picked up were two one-gallon jugs of water. But the hand's true strength, according to engineering student and co-author John Amend of Cornell University, is its versatility. Aside from the limitations noted above, he says, as long as the gripper can fold about one-fourth of the object's surface, it can pick up just about any shape thrown in its path.
You'll notice that this latest version is very similar to the version Hizook covered previously (from Colin Angle's TEDMED 2009 talk):
|
A close-up of the jamming end effector. Right now it is (presumably) positively pressurized and in a liquid-like state. |
|
The end effector is (compliantly) pressed upon an object (medication bottle). |
|
Negatively pressurizing changes the end
effector to a solid-like state, latching onto the object of interest for
grasping / pickup. |
|
Jamming end effector lifting a plastic
bottle. |
|
And a set of keys. |
|
Lifting a (dummy) patient's hand. |
|
Colin Angle demonstrating a hand-held
jamming end effector to pick up a medication bottle. |
Comments (13)
Holy cow! I just saw a comment on io9.com by Courteous_Gentleman showing a picture of Vac-Man.
I remember this toy (from the mid-1990s); my friend Kevin had one. I also recall embedding objects in its hand using the vacuum pump. It's funny how ideas work...
it seems quite possible to grip the glass from side too. it is a matter of providing the right suopport from opposite side of the gripping. may be by simple rubber support till the 80% of the height of the glass. then this baloon will expand and still can grip it.
if the creator of this video can do this exercise and upload the video it is welcome and will clear our doubts of this possibility too. waiting to see the video of side gripping the totally filled glass.
thanks for your doubt anyway. ---Ajit-Pune India
@ Robotbling, yaang, & feydaykyn:
Those are all good points. The device certainly is not a panacea. It's a (rather novel) specialized end-effector that is probably only applicable to certain scenarios -- much like the Dustpan Robot we built in our lab. As suggested by the limitations in the article, the gripper would be unable to grasp objects such as paper, credit cards, etc. However, a very low-cost design that can pick up (hypothetically) 50% of nearby objects could still be very useful in many applications.
Oh, it appears Popular Science's blog post has a picture of the coffee grounds inside the rubber sack / balloon (see below). Incidentally, I disagree with their statement that its the "best gripper yet" -- that remains to be seen, and the tests in the PNAS article are insufficient to make such a bold claim (bah, sensationalism!).
We did this stuff back in the '70s:
Good to see it's still going !!
@OldBioEngineer,
I don't suppose you have PDF versions of those documents? I'm unable to locate online copies, and haven't the motivation to dig through print library archives...
@OldBioEngineer,
That's tough to imagine, as it was about a decade before my birth -- but I believe you. It's funny how that works; there are now folks alive who never lived without internet access... ;-)
It seems that SAGE has a PDF online of the first document (link), but that its behind a paywall not accessible online through my university account. I thought that, perhaps, as an author you would have rights to post a copy...? I'll just add it to my list for things to look up next time I hit the physical library.
I saw on HackedGadgets that Carlos (of Carlitos' Contraptions) has created a DIY "Universal Jamming Gripper" using commonly available materials.
Here is what Carlos has to say:
Might I also suggest sonic vibration as another means of "liquifying" the interlocking particles.
A combination of several coincident approaches can result in very complex behavior for the particulate material.
Might I suggest that a linear actuator may also be possible, using this complex behavior , for a ferro-magnetic fluid within a magnetic field modulated by sonic vibration; or an analogous approach using modulated vibration within an electric field...
I am sure that you, and your graduate students, will have much to do in the months and years ahead.
Of course, the air in the rubber membrane could be replaced by a low viscosity fluid.
Since air and other gases are compressible and liquids are relatively incompressible, this would be a choice for a gripper used underwater, surrounded by varying presures at different depths.
Space offers a different challenge.
If a low viscosity fluid could be found, stable over wide ranges of temperature and pressures, this might be a suitable choice.
The phase transition in pseudo fluids has been studied previously, but apparently with no similar applications.
It's good to see a fundamental design breakthrough like this -- and its useful applications -- in development.