Hey everyone, I am new to this forum and I do not participate in FRC. However, I do participate in a very similar competition, JSDC which is organized by AMD. Anyway this year, the competition requires us to pick up of cones like these http://www.oronosports.com/catalog/images/large%20orange%20disc%20copy.jpg and place them in rods which are placed vertically and horizontally. My team is trying to use a suction gripper to solve this but we are very unsure of what the system should be like/what parts to use. The good thing is that we have no restrictions on what parts we can use. Has any of you had experience building a suction gripper to pick up similar objects before? If you have any ideas/experiences, I would love to find out more.
Have you developed a requirements list yet? This could help you with your design. Depending on the motion requirement, you may find that a suction cup is not the best choice (it might be otherwise).
In addition to the suction cup, have you considered using some form of non-transferring contact adhesive (like Scotch tape/masking tape)? Will the robot need to endure any specific motion?
McMaster is a decent place to start looking at materials: http://www.mcmaster.com/#standard-vacuum-cups/=ldybw8
Suction cup tape:
So here are the details of the competition,
the cones are placed in a stack http://farm9.staticflickr.com/8082/8256383614_ebf89efde3_b.jpg
and I need to pick them up and place them in cones like
http://farm9.staticflickr.com/8066/8235324311_26039f83d4_b.jpg and like http://farm9.staticflickr.com/8199/8236389408_dfcf2f8a1b_b.jpg
We have planned to build an elevator on a turntable to pick the cones up one by one and store the so that we can place them later. We are thinking of using suction to do so (plan B is to use a high friction claw using suction cup tape to squeeze them). We know that for suction there are a few types, using compressed air through a vacuum generator and using a suction generator like a vacuum cleaner directly. We are wondering if anyone have any ideas/experiences on building these suction assemblies
You can design a claw that grabs from the inside of the cone. That way gravity will keep it in place. You can add to that by putting a piston or linear actuator parallel to the arm of the gripper to push the cone onto the horizontal pole. I can CAD what I mean but after our build season.
Good point. OP, look at the Logo Motion game from 2011. There were a few robots that worked to go into intertubes with a claw and position them onto a horizontal peg.
I have no experience with suction grippers so I can’t help you, but I’d like a link to the manual/game details of the competition. Maybe I’ll come up with an idea or notion you can use for inspiration, and it would also be a good excersize for years to come 
Thank you! I will look through the forums as well!
The rules can be found here: http://jsdc.ec.illinois.edu/news/2013/01/jsdc-2013-competition-rules It’s pretty long but the important stuff is under III Match rules. Pretty interesting imo
Wow I read the manual of you guys’ game! You guys can have weapons? I would suggest you guys have swerve drive as well on your robot so you guys can maneuver past and easily dodge your oponents’ attacks.
I also suggest things like padding on the exterior of your robot so you can lower the force dealt from the impulse of an attack.
Is there a limit to how many cones you can put on a pole at a time? If not, you can put on a bunch at a time so no others can fit.
This territory game looks fun.
P.S. College students get all the fun…
We don’t get to use weapons during the actual game. After the competition, there is a demolition round where we can use weapons. A great way to end the competition every year. As such we are using omni drive so that we can solve the tasks rather than worrying too much about weapons etc. You can put as many cones as you want on a rod but you only score points by getting as many cones on top of the rods as possible. Here’s the map if you are interested http://www.flickr.com/photos/eohjsdc/8235458853/in/photostream
After discussing I think we may go ahead with our friction gripper as it may be much more simpler/efficient. We could also modify our gripper to get or place one cone/a whole stack of cones at one go.
I would actually recommend against swerve drive unless you have prior experience with it–too many points of failure; it isn’t robust in my experience. (Granted, we only tried it once. There are plenty of teams with better designs than ours).
If you use a gripper tht expands to hold the inside of the cones, make sure you can place them on the rods and retract your claw without pulling the cones back off the rod. That happened a lot in 2011 for inside grippers.
Hmm we are actually thinking of using an outside high friction gripper. We have the exact cones and they are very flexible. With enough friction you can squeeze them from the stack and place them down/pick them up one by one.
But yea we also need to pick up stacks of cones so we need a mechanism to grab the whole. They aren’t very heavy and we may use the inside gripper mechanism together with our single cone high friction gripper. If it’s too hard to use the inside gripper (as the stack of cones we need to pick up from are placed in a rod itself, so you gotta make sure you don’t hit the rod) we may just use a big claw and grab the whole lot from the bottom. The cones are really light and small thankfully.
If you want high-friction material, I recommend this stuff. It grips frisbees incredibly well, and I see no reason it won’t do the same for cones.
With a little innovation, an inside gripper can be easier to make and more efficient than the friction gripper. To pick up stacks of cones, just have the claw be made around a hollow pole so it can go down one of those poles. Also, check out Team 16’s 2011 robot. They had a claw that could even pick up deflated tubes and I think their inside gripper used only one actuator. I think it’s on YouTube just type in Bombsquad 2011 Robot Unveil.
So yep, here’s an update. Before I started this thread, we already bought some stuff to test out the suction. We first got the vacuum pumps off sparkfun: https://www.sparkfun.com/products/10398 and we tested them without anything. They felt weak and we lost hope so I started this thread to look for alternatives. Today, we got our hands on the suction cups and we decided to try it for fun, here was our setup http://i.imgur.com/ykqVI32.jpg vacuum pump, 12v, some tubing and piab pigrip suction cups.
these were the piab suction cups http://i.imgur.com/YeqyTBB.jpg
and when we tested them…
http://i.imgur.com/bb4Yddq.jpg they worked really well! There are few small things such as not sucking the cones when the cups are placed on the part of the surface with ridges, but we can get by it! Thank for all your help
I think that a gripper like this would probably be pretty successful.
That’s a neat challenge. Do you have to pick up one at a time? If not then I would just have a thin fork-shaped plate that slides underneath and picks up the whole stack lol.
If not I would use some sort of sticky material on two fingers (to go on either side of the vertical peg) so that you can just lower your elevator on top of the cone and then raise it back up with the cone sticking to the fingers. Then your fingers can be on some sort of actuated arm that rotates up 90 degrees (look at the elevators and grippers from FRC 2011, Logomotion), you can then slide the disc forward onto the peg and pull downwards with your elevator to pull the sticky tape off of the disc.
That’s how I would do it.