Re: Universal Robotic Gripper
 

We could use this for VEX Round-up right now !

Re: Universal Robotic Gripper
 

My thoughts would be that you need to find the surface area of contact with the balloon, the coefficient of friction between the balloon and object, and finally the force with which the vacuum is pulling the balloon in. Then from there you would be able to calculate the force with which the object will be held, however those are my initial thoughts which I feel are far off from what you would actually need in order to calculate the force.

Re: Universal Robotic Gripper
 

I would think it would vary GREATLY from grip to grip as well. I wish our team had build a suction cup at some point so I could go play with this concept and learn more.

Re: Universal Robotic Gripper
 

If you're serious about using this, I'd think that the coffee bean usage is a clear violation of the no food in the pits policy :P

Actually, how well would this work with styrofoam pellets? Does this require that the material inside the balloon not compress?

Re: Universal Robotic Gripper
 

The granules must not compress in the vacuum for this type of manipulator to work (well).

Re: Universal Robotic Gripper
 

I think the rule deals with toxic substances....not ground coffee beans

Re: Universal Robotic Gripper
 

Yes I completely agree with that.

I could envision there being some objects that are very tough to pull out of the grip, while others are only just barely being held in.

Re: Universal Robotic Gripper
 

I wonder how you could make this with FIRST resources. The compressor could certainly be used for suction. You'd have to have some sort of filter system/mechanism to keep the coffee grains from sucking into the compressor. You might just be able to put a screen inside the balloon. It might be tricky to use this gripper and air tanks for pneumatic pistons, since both require different uses of the compressor and at different times. Then you'd have to figure out how to make/machine an attachment from the balloon to the air hose. This attachment would also have to have mounting holes on it for mounting it onto an arm or the robot.

Re: Universal Robotic Gripper
 

The compressor can't suck. It only compresses air, it doesn't create vacuums.

A few years ago (2007), a device was included in the KOP to create suction from air pressure, as well as two suction cups. (I forgot what it is called, but I know we still have ours in our shop).

I like this gripper. I still like roller claws better.

Edit: I looked it up. The device in the 2007 KOP was a Venturi valve.

Re: Universal Robotic Gripper
 

I thought the compressor is what made that suction kit work. But still, you could hook up a tube to the "in" side of the compressor and it would suction, right? I even remember that there was a rule stating that we couldn't do this (implying that it could be done).

Re: Universal Robotic Gripper
 

The "in" for the KOP compressor is a felt patch on the side. There's no place to attach any fitting, and the draw there isn't all that great anyway.
It's not one of the two ports opposite each other on the top of the compressor. Those are both output ports.

A Venturi works because a flow of air is constricted by the device to speed it up. An increase in air velocity is matched by a corresponding decrease in pressure. The faster moving air draws a vacuum. Like blowing across the end of a soda straw.

So continuously forcing compressed air through the Venturi device results in a vacuum. It doesn't take a great deal of air to make it work.

Re: Universal Robotic Gripper
 

Oh, I see, I thought one of those output connections you talked about was an input.

But of course, like this Venturi device, there are other options.

Re: Universal Robotic Gripper
 

There should be fitting you can purchase that will take the air going in to create a vacuum effect, similar to how a carborator works. This was mentioned to me by a mentor last year on how we could utilize suction cup. I'll try and find an example of this fitting asap.

Re: Universal Robotic Gripper
 

That would be a Venturi device.

Re: Universal Robotic Gripper
 

Are there any teams out there thinking of researching this idea to implement it possibly to the FIRST Game?