Universal Gripper - Syringe Powered

The “universal gripper” developed by researchers from Cornell University, the University of Chicago, and iRobot inspired me to create my own version. The YouTube video is quite impressive. The gripper can form around very asymmetrical and smooth shapes and still pick up the object.

I gathered the materials below and decided to create a gripper of my own that could be incorporated into one of my robot designs. Adding a vacuum pump or a powerful air mover seemed difficult and probably unnecessary. So I started to think about vacuums.

I remembered that when they were filming “An American Werewolf in London” that Rick Baker used hypodermic syringes hooked up in a line. When a really big syringe was compressed at the end of the line, the little ones popped up creating the appearance of a spinal column erupting below the skin of the creature’s back.

I decided that the same idea might work with the “universal gripper.”


In addition, I thought that using a funnel could work nicely for balloon support. Playing around with it, I thought that adding a pressure sensor inside of the funnel would allow the Arduino to apply suction when the balloon came into contact with the object to pick up. This lead me to Plusea and her instructables using velostat and flexible materials.

Amazingly, it all seem to work. Follow these steps to see how I did it. You can probably see alterations that would improve the design.

Step 1: Materials

Materials:

• Good quality latex balloon
• Aquarium plastic tubing
• 60 ml veterinarian syringe
• 11/64” brass tubing
• zip ties
• Bond 527 cement
• Conductive thread
• Needle
• Craft foam
• some #6 bolts and nuts
• 5 cm of U channel aluminum
• TowerPro servo MG995
• flat stock aluminum
• an Arduino or other microprocessor

Comments

[AJMansfield]

The more jagged edges you have, the more finely the grit is actually able to compact on itself, at least by one theory. Finer grit would be better, I think. The only thing it really has to have is sheer thickening (think cornstarch and water).

[techiebot]

If you read the article, the researchers discuss the optimum material that is fine but not smooth so that the particles grip onto each other. Their conclusion was that coffee grounds make an ideal material, and they are very light. I think your cement idea is interesting, but the material needs to be easily deformed so that when the balloon is pressed onto an object the material inside the balloon can "flow" around the object.

[AJMansfield]

Portland cement powder actually flows extremely well; when completely dry, it behaves very much like a liquid, actually. It will even splash up if you drop an item into it (it's far cheaper than coffee grounds, too: $5 gives you around 50lbs of it, which will fill 1-2 cubic feet of space). Plus, you can mix it with gravel, sand, and water to make concrete (if you want to be really fireproof, mix powdered fireclay with it).

[AJMansfield]

I'd probably use something like Portland cement for the fill material, because its much finer than coffee grounds, sand, and most other types of grit materials.

[propellerheadgeek]

Hi - nice instructable. I made something similar awhile back, but used a different approach to the suction device; should be perfect for your gripper and will let you get rid of the servo AND the syringe...  a miniature pump

[techiebot]

The pump looks cool. And so cheap! Depending upon how the pump is constructed, it might have to remain on in order to keep a vacuum. What I liked about the syringe is that once the plunger is pulled back, it takes no power to keep the grip on the object. And for most robots, power consumption is a major concern.

Thanks for the pump source.

[AJMansfield]

Put a normally-shut solenoid valve between the pump and the gripper.

[rj44319]

This would be great for a quad rotor to pick up items and move them around!!!

[AJMansfield]

Having to lug around that balloon full coffee grounds or sand or cement or whatever, might be too heavy, though.

[rj44319]

coffee grounds are not heavy

[formellini]

Hi, whi don't you put a spring in the siringe to keep always active the gripper?
I think is more easy press a siringe with one hand than pulling. with the spring inside the gripper is autolocking and you can hold an object without using your Hand, you need it only for grabbing and releasing.

[techiebot]

That is a good idea. I was just experimenting with the syringe in the video to see if it would work. Then I had to see if the servo was strong enough to pull the plunger back. My real goal was to have it totally automated and hands-free.

[survivorwolf]

I like the spring idea or i saw a neat instructable recently about how to turn an aquarium pump into a mini vacuum pump
It could be possible to combine both this and your project....
http://www.instructables.com/id/Electric-Vacuum-Pen-From-Aquarium-Air-Pump/

[techiebot]

Thanks for the link. My idea was that every robot struggles with having enough power to operate. I thought that a servo holding position would consume less power than any pump I could think of. Plus, it's silent. But the aquarium pump is something I want to look into. Thanks again!

[Sketch98]

Can you pick up round or smooth things like a ping pong ball?

[techiebot]

It actually does pretty well with smooth objects. The rubber membrane of the balloon has a certain amount of friction to it. If you read the article by the university researchers, there's also some vacuum created between the object and the membrane. So it works better than you think it would.

[vigilantice]

Ha a buddy of mine is doing the science olympiad robot arm competition. I had seen the cornell version a while back and told him he should try to do something like it but he told me it could never be done cheap enough and without a vacuum pump. Showed him, didn't you? Excellent job on the gripper.

[ElectroFrank]

Perhaps this could be useful to the elderly and disabled, if the whole system was installed in something like one of those "litter picker" grab sticks.

[techiebot]

I agree. It seems to me that there could be many uses for this concept. It could help a lot of people. I imagine that it must be extremely frustrating to not be able ot pick up a medication or some other small object successfully.
Thanks for the comment.

[ramicaza]

Thats supper cool!!!!! i must use this in a robot! thanks for the instructable

[Kaptain Kool]

Wow, great idea!

[LifeWarrior]

sorry pic screwed up this was the idea

[techiebot]

It seems like it could work. Again, you are depending upon the strength of the bulb walls to create a vacuum. I didn't do any scientific testing on how much vacuum is needed to "jam" the coffee into a rigid form. Let me know if it works.

[LifeWarrior]

Cool, when I can I'll try it, I have several other projects in the works right now, haven't had too much time to try many but this one is definitely worth the work up. Now that think of it a silk screen of some kind might prevent the grounds from getting sucked up through the hose, and with that maybe a shop vac attachment would be a cool addition too. Just brainstorming for when I try this.

[techiebot]

My local hardware store sells a very fine mesh metal screen meant for use in water pumps. I don't know what it's called, but I bought a piece some time ago. Perhaps it would work and not restrict the flow of air.

[LifeWarrior]

I'll check for something like that, thanks for all the info

[techiebot]

That looks good for a one-way valve. What would you do to get positive pressure back into the balloon?

[LifeWarrior]

I'm not sure how it works, I just put together this picture on how I think that type of valve operates, but I think that it follows your line of thinking that the walls of the bulb are so thick that it pushes the upper bearing through force up letting air in, but I'm just guessing. They sell these on ebay and after seeing your 'ible I was just wondering if you've ever encountered those or tried one for something like this because of the pumping action I wonder if it would it create the same effect on the balloon. I was considering buying one for a manual operation to try this project, but being the building I was interested in your experience regarding a pumping action rather than a single drawing motion like the syringe.

[LifeWarrior]

Very cool, I wonder if this could be done with one of those squeeze bulb valves instead if a syringe, and also what would you say is the max weight that it can pick up

[tjesse]

YES, I would like to know if it can be used with a turkey baster style bulb! Good thinking!

[techiebot]

I have used the type of bulb you suck boogers out of kid's noses for positive air pressure. I made a March Hare mask with a balloon hidden in the hair. One ear was hinged with a fabric hinge and rested on the balloon. A length of aquarium tubing ran down the back of the mask, into the costume, down the arm and was hidden in the actor's hand. When the actor squeezed the bulb, the ear went up in a crazy March Hare way.

It certainly might be possible to use a fairly rigid bulb to create the vacuum. If the bulb is too soft it probably wouldn't be strong enough to create enough vacuum. Only a test will tell!

Great idea!

[LifeWarrior]

I was thinking of one of those type that has the 2 bearing valves so every time you squeeze the bulb air is expelled and when you release it draws the air from the balloon creating a pumping action

[RWWestbrook]

I like the concept of using this to grab things, especially for grabbing non-magnetic objects or if you dropped something between the body panels of a car such as a nut or bolt and the magnet can't get to the object without sticking to the car first. I noticed that there was still the issue of coffee grounds entering the hose. Would it be possible to make a tiny sock out of cheesecloth or some similar material to protect the hosemouth inside the grounds? It might make the seal on the syringe hold less of a vacuum if the coffee grounds get between the rubber seal and syringe tube. However, this is great documentation of your design process, and I would like to make a grabber for myself.

[techiebot]

Yes, I thought of putting a bit of gauze over the end of the tube and hot gluing it in place. But I had a good seal on the end of the balloon, so I've left it so far. If the tubing goes straight up from the balloon, very few coffee granules leave the balloon.

Thanks for your comments. Making the grabber is really quick and easy. I hope you try it out.

[blckbuster]

sourcing a durable balloon is probably the next step, as it might not take much to rupture your coffee gripper

PS in the future if you get inspired to invent daleks, don't do it

[techiebot]

DALEKS!!!!!! Great idea! I thought that the balloon would be fragile too, but since it's not inflated, the walls are pretty thick. I did get a higher quality one. I think if the walls were too thick, they would not form around irregular objects. So far I can not tell that I have any pinholes and the vacuum still seems good. It might be worth a try to put a balloon inside a second balloon so the wall is double thick.

Good idea!

[12beav]

While watching the video an idea popped into my head. Instead of the syringe pumping air pumping air back in once you pick up the gripper, why not had a switch to release the pressure?

[aessam1]

Really amazing
hope to see a robot using it soon.

[newtonsz]

Marvelous! very simple and functional.
Congratulations

[Kiteman]

Very cool, but is it my imagination that the gripper currently lets go as soon as the pressure is off?