Competitive Intakes

[Jay O'Donnell]

Originally Posted by BJC

33’s primary design objectives for our intake were:

1. Had to be two disks wide for the 7 disk auto.
2. Had to be extremely fast (469 in 2012 was our benchmark)
3. Had to be able to properly function over wrinkles/tape on the carpet.

I find it funny that your third design objective ended up being our biggest problem. I think we broke our intake almost ten times just on tape. It was something we completely overlooked and didn't think of as a problem.

[Cash4587]

Originally Posted by MStump

How did you guys do a double wide intake? My team is working on an intake mechanism for a summer project and we want to be able to do a 7 disc auto but cannot figure out what the most reliable way to do a double wide intake is. The main problem we have run into is figuring out how to get one disc to enter before the other.

We were thinking about doing it like Miss Daisy did where they have a spring-loaded intake with one side in the front having larger rollers than the other side.

Anyways please let me know what you guys did to solve this problem, thanks.

Why not just do a 1986 pancake flipper feeder? Sounds like you will only use it for auton anyway? Just a thought.

[the.miler]

Got a shoutout from 3173, had to respond! I designed our floor collector this year, and it seems to be the system that people remember when they see our robot. There are features that I would never replicate on that collector if I could do it over . . . there are also great features, and I've tried to detail them below.

Mooretep had an awesome video (0:30 has a really nice shot): http://www.youtube.com/watch?v=GqfuRlymtSQ



Official Reveal (showcases initial testing): http://www.youtube.com/watch?v=jmdET56tukM
Official Recap: http://www.youtube.com/watch?v=w79l4VhjrD0

Ironically, the floor collector wasn't really our top priority (we didn't have priorities due to the fact that we tried to do everything; don't do that!), so features such as being able to funnel really well and take two discs at the same time didn't make it into the final design. If we had properly valued the collector, we would have thought differently and implemented those features.

Cool Attributes:
At the mouth of the collector, there are actually two rollers, one on the bottom and one on the top. We arrived at the same conclusion as 33, that the bottom roller for kicking the disc up was crucial. The coolest part was really that we did not drive it using anything nearly as complicated as a gearbox; it was just a twisted belt run from the top roller. I can get a picture later, but it was something like this: http://www.chiefdelphi.com/forums/sh...ht=2826+teaser

That bottom roller kicked the disc into contact with the upper roller, and that powered the frisbee through the rest of the system (geared at 18 ft/sec roller surface speed) and out into our storage subsystem.

To prevent our collector from getting caught on the carpet and irregular surfaces we installed wheels for the collector to ride on. This was another pretty cool feature, we machined two delrin rounds with holes for bearings, turned down the ends of two 3/8" bolts to 1/4" diameter and the bearings rode on that makeshift shaft.

What I would have liked to do:
Here's a really easy way to make your collector take two frisbees side by side. Make your collector funnel to the side, kind of like 233's or 973's collectors. One straight edge, one slanted edge. Our prototypes indicated that this worked really really well, and we only didn't implement it because our robot design forced that compromise.

Alternatively, do something like 971's collector (I would note that both their 2012 and 2013 robots are absolutely phenomenal in handling game pieces throughout their system) . . . http://www.youtube.com/watch?v=6bsWRIMV9CY It would be really cool if they posted on this thread

Hope this helps! Collectors this year were really challenging, and it's really interesting to see how other teams approached that problem. Keep the responses going, I'm having a blast reading this thread

[themccannman]

We had a very long, arduous journey over the course of the season to prototype and perfect our intake. Our original intake design was like many others with a single double wide roller in the front and a "scooper" plate underneath. Here's two pictures of our original intake design, the pool noodle on the front was just a bumper to protect the roller underneath. The entire roller was on a hinged arm that allowed the roller to actuate vertically



In this picture the black rollers were made of a low durometer urethane called sorbothane, it was by far the most frisbee-adhesive material we could find. If you just laid the sheet of sorbothane on a frisbee you could pull the frisbee across the carpet with only the weight of the sorbothane holding itself down.



This intake design was fairly successful, it picked up almost every frisbee we touched, however like other teams we occasionally had some jamming problems when feeding 2 discs next to each other and the scooper plate getting stuck on the carpet lip around the pyramid. The other problem was that it would push the frisbees a short distance before picking them up which was a problem in autonomous. We went back to the drawing board using 254's intake as inspiration. Our final intake design worked better than we ever could have dreamed.



Our final design used a thin front roller with a polyurethane sheet wrapped around it that had similar traction properties to the sorbothane. The entire intake was wide enough to pull in two frisbees next to each other. Only having the traction on the center of the front roller allowed us to pull in one frisbee at a time without them fighting each other while being pulled in.

Behind the front roller we had a counter rotating roller with the same polyurethane traction material on it that lifted the edge of the frisbee and pulled it into our hopper. We also had another roller directly above it with a large brush on it, rolling in the same direction as the front roller, to assist the frisbees getting pulled in after the bottom roller had lifted the edge. This intake design worked flawlessly, it instantly picked up any frisbee touching the front roller, never had jamming issues, and had an additional, accidentally built in feature, if you picked up an upside down frisbee then lifted the intake it would flip the frisbee out right side up to be picked up again

Our final intake also had no bottom scooper plate and the entire intake rolled on two steel track balls which kept the front roller at a consistent height and allowed easy transitions over the carpet lip. Our intake also took a much heavier beating than it should have including a full speed hit against the pyramid and several pushing matches with other robots. We did end up bending the side plates that make up most of the intake however we reinforced them with a set of back-up plates that we had brought along in case that happened.

I'm sure most of you saw this live but here's a match with our intake after it had been "Frankensteined" back together.

http://www.youtube.com/watch?v=U_blP_tD8Yk

Thanks to 973 for the great quality video of the einstein matches.

[MichaelBick]

Very interesting about the different materials you used on your rollers. I wonder what other materials people used for their rollers.

[the.miler]

We used tennis grip tape wrapped over spongy weather stripping (strips of soft foam with an adhesive backing) for our top rollers. For the very thin bottom roller, we just wrapped the grip tape directly on.



Both the tennis grip tape and weather stripping worked out beautifully. Gripped the discs really well, and didn't wear down at all. Very low maintenance, and rewrapping a roller was a breeze. The old tape and weather stripping on a single roller could just be peeled off and the fresh replacement applied given just a couple of minutes with the collector.

Our only regret is not using black colored grip tape, the white grip tape got dirty and didn't look as nice

Weather Stripping: http://www.homedepot.com/webapp/cata...gry=Search+All