Competitive Intakes
 

I think building a competitive roller intake was one of the hardest challenges this year. Our team for example trashed our intake design midseason, after spending many, many hours prototyping. However many teams still built fast intakes, despite our team's troubles. What were the challenges that your team faced in building an intake? What designs overcame these issues? What designs led to the fastest, most consistent roller intakes?

Re: Competitive Intakes
 

How about not using rollers at all?

*See thumbnail now*

Really, we decided to just leave space for the intake and save it to design last. And, well, someone had the idea that we have an intake like a carwash, so we prototyped this design. With a few tweaks, it worked really well.

Sometimes you just need to think outside the box.

Edit: we have the mechanical capability to do a 7-disk autonomous easily (at least in terms of picking up), but we never got to program it during the season.

Re: Competitive Intakes
 

We built a pretty darn fast pickup. It is capable of a 5-shot auton. Picking up the two frisbees side-by-side was probably our biggest challenge. We fixed this by racking the outside roller at an angle- the left side is .25" lower than the right side.

As you can see from the picture, we have two pivoting arms with rollers on them that run off one RS-775 motor. I'm not sure of our gearing (I can check it tonight if you want) but it is plenty to pick up frisbees no matter how fast the robot is moving. The first, outside roller hits the frisbee up onto the ramp. The inside roller (it's hidden by the frame in the picture, but it's there) pushes it into our hopper.

In the picture, the shooter is up. In order to pick up frisbees, it has to be down. The edge of the cylindrical canister lines up with the ramp under the rollers.

http://www.chiefdelphi.com/media/img...9236795e_l.jpg

Re: Competitive Intakes
 

I was responsible for the design and fabrication for the intake mechanism (we called it Disc Acquisition Device, or DAD for short). We worked on a few prototypes but the best one was a top roller with a bottom "scoop" (essentially just a slide that would drop down when we were gathering disks, so as not to pick up excess) this design worked nicely and reliably for bot right-side up and upside down disks, though it never made it to the robot.

The team responsible for transportation of the acquired disks to the hopper was a bit behind schedule. If you would like to see video of the DAD in action, I am sure I could get that posted for you.

Re: Competitive Intakes
 

Ours used a roller for the intake, and a scoop. It's a little slow, and we also have trouble with jamming when picking up two side by side frisbees. We tried the trick of angling the intake roller so when encountering two disks one gets sucked in first. This ended up making the single disk pickup less reliable.

We are currently designing and rebuilding a new arm as a summer project.

Could I request that people link to video of their working arms?

Prototype testing:
http://www.youtube.com/watch?v=XVD6P3wNRUg
Integration testing:
http://www.youtube.com/watch?v=rNaJeDeVASo
Final testing:
http://www.youtube.com/watch?v=7XSihXrLHZY
Match footage:
http://www.youtube.com/watch?v=BZ0g1o40oPA#t=01m22s

I should note that we designed the arm to be easily replaceable if damaged, which was necessary in Richmond. This was cited as one of the reasons we won the Quality Award at that event.

Re: Competitive Intakes
 

You probably would have had to compensate by leading with the side where the roller was lower.

Honestly, I never considered picking up two discs at a time. I made the opening 16.5 inches (quite wide for the purpose) to accommodate a disk coming in from any number of given angles. I was just assuming that our elevator (or disk transport) would be build fast enough to process one after another. I will try to get some video up soon.

Re: Competitive Intakes
 

We had a ground intake that worked but never made it to competition. It was the classic flat flexy bottom plate with rollers and belts on top.

Our problem lay in moving the discs into our hopper. We had planned on a magazine that indexed upward (bottom loading). Once we realized that the indexer was too complex to fit in the area we had slated for it, we moved to a simplified top loader and that eliminated picking up under the bot.

Re: Competitive Intakes
 

Our floor collector this year was a great success. I was in charge of designing and prototyping the collector mechanism, which our bot solely relied on. After much prototyping, we made the decision at the beginning of week 2 that we would only collect discs from the floor. While this was a risky decision, it allowed us to cut down significantly on the complexity of our design. Instead of using a hopper, discs were stored in a linear path to the shooter. Our 2013 bot was one of the simplest and most competitive in our history.

Our design consisted of a bottom scoop that dragged on the ground, and an articulating intake roller that compensated for the change in angle as discs were collected. The collector was only slightly larger than the width of a disc, but we believed that by adding a camera facing the collector, we could still ground load from across the field effectively during a match. The system worked extremely well throughout competition, and functioned properly for each of our 44 official matches. It's robustness and reliability helped us win two Motorola Quality awards this season, and go undefeated at the Connecticut regional. We were able to use the collector to run feeder station cycles as well. We realized that loading from the floor of the feeder station was actually a lot faster than most human loaded teams. Another cool feature that we discovered was our ability to flip upside down discs. By running the intake roller in reverse, and driving into a disc, we were could reliably flip discs, although we never used this on the field.

We did however, encounter a few problems. At first, we tried using poly-cord to drive the discs. This produced very mediocre results. We experimented with using VEX wheels on the discs, driven by poly-cord, which produced much better results. In the end, we went with Banebots 2 7/8" soft compound hex wheels. These produced an incredible amount of friction on the discs, and worked phenomenally well on the robot. Another challenge was placing the roller wheels in the right locations so that it would maintain contact with the disc as it traveled up the scoop. This was done with prototyping, and we transferred the measurements to our production collector. Finally, maintenance became a big concern. On our practice bot, our collector assembly wore down several times, affecting it's performance tremendously. The wheels, while great on the field, lasted for one competition at maximum.

Match Video:
http://www.youtube.com/watch?v=KsQPrFUpKmk
We only fired 3/4 in auto, so there was still one in it when we went for the center line in teleop. Since our bot is capable of carrying a maximum 4 discs, it appears as though the last one wouldn't collect, since it was full.

This is our bot before WPI. We extended the outer shaft and added extra wheels for Connecticut.

Re: Competitive Intakes
 

Our team decided day one we would need as much time as possible to get a "competitive" intake prototyped, put into cad and fabricated. We set a small group of students who wanted to work on the intake aside from the beginning of the build season and gave them the task. We also realized our resources were already going to be spread thin so we had the mentality of if we can get it done then we will use it but we focused more on shooting and climbing. Our week one regional came around (Hub City) and we had lots of trouble getting our machine debugged mechanically and with software. We were playing a match against 1986 Titanium and when they hail a deadly fire storm of 7 disc above your head during autonomous within the first 15 seconds we soon realized how demoralizing it was and how it gave them a psychological advantage let alone a big point difference. When we came back home we definitely wanted to get the intake done. We got it working well and worked out some kinks before the Dallas regional. Our biggest problem was getting the intake to not "chatter" while driving and picking up two frisbees side by side and funneling them in without getting jammed. Got a centerline 5 disc working from both sides of the pyramid, a 7 disc auto from middle and a 5 disc middle working. (Enough of my story)

Our intake is lowered while our "shooter"is lowering also. We use pneumatics to get the robot to lower the intake by retracting the piston. It was really reliable and didn't have much trouble with it. We use a banebot motor (Don't know what specific model) to drive one of the rollers and the other roller is driven my the polyurethane belting connecting the two rollers.

Picture of the robot/intake:
http://t.co/fUX4fkhyEj

Here is video of the testing phases before worlds:
http://www.youtube.com/watch?v=DkyqsW11xFg
http://www.youtube.com/watch?v=wnNroKsyFaU

Here it is in action:
http://www.youtube.com/watch?v=2j9ov03mOyA

Re: Competitive Intakes
 

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.

Re: Competitive Intakes
 

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.

We had a very successful prototype using an overhead roller and spatula. However, this didn’t meet our 3rd functional objective.

Recognizing that the key to intaking was getting the leading edge of the disk off the floor we began prototyping a counter rotating bottom roller. This resulted in a second very successful prototype using a 3/8” fiberglass rod sleeved with surgical tubing. However, the very tight dimensional restrictions (54” cylinder) meant that this design was almost impossible to package.

Because of packaging constraints we began prototyping large diameter bottom rollers. These evolved to have “fingers” and we ended up with AndyMark stars cut down slightly.

The final intake pretty much met all of our objectives. We consistently averaged 6 disks in auto throughout the season, and the collector functioned properly up to about 1/2” off the ground and wasn’t affected by tape or carpet wrinkles. It didn’t quite meet the 469 in 2012 requirement but it was still good enough that we never had to wait around for disks to enter the robot.


Photo by Dan Ernst

Re: Competitive Intakes
 

The way we solved this problem is to have a varying diameter roller which can articulate on an axis. When it touched 2 disks at the same time, the disk on the larger diameter portion would get sucked in and lift the roller up so the other disk isn't getting engaged. When the first disk is in our system, the roller falls back down due to the weight of it and picks up the second disk. We had to play with the height of the roller off of the floor, the proportion of larger BB wheels to smaller BB wheels etc.

These pictures show the mechanism:
http://www.flickr.com/photos/team341...7632915395077/
http://www.flickr.com/photos/team341...57632545513277

Re: Competitive Intakes
 

We actually solved this problem by attempting different variations on how the tread was mounted (the direction of the tread when the rollers rolled) and we used a hex standoff to kinda hold the frisbee so the other one can come in before the next one comes in. The different combinations of tread configuration allowed the frisbee to be pulled to the side where the first frisbee came in. So the frisbees come in side by side, the right frisbee goes straight in and the left frisbee kinda rotates to the right side then entering the robot right behind the first frisbee. I'll add a picture when I get home from school.

Re: Competitive Intakes
 

Find someone on 846, they had the quickest one that I saw in person this season. They used a roller and a piece of plastic to lift the disc into a pulley system which then dropped it into their hopper. I can't give you all the specs but it was by far the fastest I saw in person.

Re: Competitive Intakes
 

While ours wasn't double-wide (in retrospect, it should have been..) it still worked very well. It was as simple as a pivoting front roller with a piece of lexan on the bottom. Flat polybelt drove it off of our conveyor system. The entire pivoting assembly was also tensioned down with some surgical tubing. At first we had trouble gripping the frisbee, but we wrapped a short piece of solid core surgical tubing in the center in a helix and we never had any issues since. Heres some cad and a video:



Videos:

Before the surgical tubing grip

With the grip