Re: what was the best shooting mechanism for 2016?
 

Thanks I had already read that post, I was wondering if you had any additional information and pictures.

Re: what was the best shooting mechanism for 2016?
 

This side view shows the catapult arm after it has reached its most forward position and has begun to retract:



The arm is nearly the length of the robot and pivots on the front frame rail. It's driven by 2 mini-CIMs through a toughbox mini and #25 chain with an overall ratio of 28:1. We have an incremental encoder on the gearbox so we know how far its traveled is each 20mS control loop.

I don't remember the exact weight of the catapult arm but it is extremely light. The arm itself is 1.25" square, 0.040" wall thickness 7075 tubing that came out of a sponsor's dumpster. The "dish" the boulder rests in is carbon fiber. The block of pink foam on the arm was added after week 3 and reduced the boulder settling time substantially.

Re: what was the best shooting mechanism for 2016?
 

The best Shooting mechanism was 971 Spartans shooter would retract and it had probably the vison tracking. Don't teams like 16, 1678, 1538, and others who had good rotational platform which made them "UNBLOCKABLE".:ahh:

Re: what was the best shooting mechanism for 2016?
 

While we may not be able to compete with teams like 254 or 971 in shooter design, we at 2877 are proud of our Pnuematically fired rolling catapault.
Our biggest innovation was the placement of servos on the end of the shooter tips. Combined with vision code, this gave us the ability to precisely control the distance and arc of the shot. As our vision code evolved, we came to the realization that by putting the servos at different angles we could aim the ball to the left or right which reduced our time to shoot greatly.

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Re: what was the best shooting mechanism for 2016?
 

Now that's really cool. Do you have some videos of this in action? We'd joked about changing our left/right shooter speeds during the season to create a curveball, but never thought about really trying it.

Re: what was the best shooting mechanism for 2016?
 

Wow. That is really cool. Did you guys win any awards for that specifically?

I also just wanted to comment on this. We had this same conversation in our team, and it went from joking, to half serious, to actually trying it. We probably spent about 2 hours trying to get a curveball to work with our dual wheel shooter, and while it did curve a little, the shot power was reduced a lot, so we scrapped the idea of using it. Would not recommend.

Re: what was the best shooting mechanism for 2016?
 

Most of the boulders I saw used on the fields were in like new condition. If a boulder got a big tear or rip during a match they would replace it with a new one. I don't think one is better then the other, I think its more of what works best with your team. I think one of the reasons we chose a wheeled shooter this year was because we have done them before and have experience on how to tweak and adjust them.

Re: what was the best shooting mechanism for 2016?
 

Brand new balls still performed differently than slightly used balls.

Re: what was the best shooting mechanism for 2016?
 

Unfortunately, I don't have any close up video(might try to get some at our next meeting), but you can see a pronounced difference in how long it took us to line up at each of our events.
At WPI, our first district event, it was taking us around 6-7 seconds to line up and shoot(Our robot is on the blue alliance shooting at the center goal)

At our next event, BU, it was in the 3-5 range(robot on blue alliance shooting into near goal)

At NEDCMP, our final event, with the "Differential Flaps" fully implemented, it was 1-3 seconds depending on how close our angle was before we let the robot take over. Our robot is the robot nearest to the center goal


We won Innovation in Control at BU and NEDCMP

Re: what was the best shooting mechanism for 2016?
 

That's ridiculously cool. It's also a great solution to getting hit while shooting if you can't seem to get a shot from a more protected location work.

Re: what was the best shooting mechanism for 2016?
 

Thanks so much! The "Differential Flaps" were implemented in response to playing under heavy defense(shoutout to 2262 for indirectly causing our shooter to improve). Our catapult didn't have the capability to shoot from the outerworks or the batter accurately, so we opted to quick-shoot.

Overall, our season ended in a slightly disappointing fashion, as we were ultimately brought down by our tread failure, and missed out on a trip to Saint Louis. Overall the season was great, but it was somewhat disheartening to think about how good our robot could of been with a better drivebase.

We are in the process of improving the drivetrain and hope to be playing at our peak at BattleCry this weekend.

I suspect our programming team will write up a whitepaper detailing everything about our code and vision tracking for anyone interesting in the nitty-gritty detail

Re: what was the best shooting mechanism for 2016?
 

I've been thinking about this thread again, and I decided to analyze IRI this time as a sampling of the best teams in the world ought to produce the best shooters as well, right?

IRI had:

• 26 Single Flywheel Shooters
• 21 Catapults
• 11 Double Flywheel Shooters
• 2 Linear Punches
• 9 Robots without a high goal shooter
• And 1619's shooter, which I'm not quite sure how to classify, but it used a lot of wheels. If someone from 1619 would comment, that would be cool.

Of those teams, in eliminations were 32 teams as follows:

• 14 Single Flywheel Shooters
• 7 Catapults
• 4 Double Flywheel Shooters
• 2 Linear Punches
• 3 Robots with no high goal shooting
• 1619

There are a few ways to analyze this data, so I've put it into a little table. The first one is the number of teams with that type of shooter compared to the total number of teams at IRI. The second is the number in eliminations with that type of shooter compared to the number of teams at IRI with that shooter, and the third is the number of teams in eliminations with that type of shooter relative to the total number of teams in eliminations.


This data could mean absolutely nothing, and the shooters at IRI could be happenstance and good teams just happened to draw their inspiration from 2012 robots or something. Or maybe not.

I think the most interesting numbers are the comparison between the first row and the third row. Despite being the largest group of robots at IRI, single flywheel machines were over-represented in eliminations, while the next three largest blocks(Catapult, Double Flywheel, None) were all underrepresented in eliminations. The middle row also represents that, with more than 50% of all single flywheel teams at IRI making eliminations.

Knowing this information (and also my experience in the past with some very finnicky double flywheel shooters and catapults), I would use a single flywheel shooter in a similarly styled shooting game in the future (although God knows I'm going to eat these words when I want to pursue some other shooter a few years from now and my students do some research and find this post).

Re: what was the best shooting mechanism for 2016?
 

Very cool data you have here! I'm happy to see that 100% of teams with a 1619 style shooter made it to elims, haha. Anyways, on to our shooter design.



Basically, two horizontal rows, each with four four inch colsons, opposite from quarter inch polycarb, with about 2 inches of compression.

Personally, I most enjoyed watching (and listening to) the linear puncher shooters. However, different shooters entail different constraints and/or requirements, and can all yield great results when well optimized.

Re: what was the best shooting mechanism for 2016?
 

Really interesting writeup. Could you post the lists of which teams use which shooting mechanisms? I'd like to take it one step further and see how far the various mechanisms made it in elims.

Re: what was the best shooting mechanism for 2016?
 

Well lets take a look

Winning Alliance
2056 - Single Flywheel
118 - Catapult
33 - Single Flywheel
4587 - Catapult

Finalist Alliance
1114 - Single Flywheel
195 - Catapult
225 - Dual Wheel
1405 - Defender

Semi Finalist 1
1619 - 1619 Style
1241 - Single Flywheel
133 - Catapult
868 - Single Flywheel

Semi Finalist 2
3620 - Single Flywheel
67 - Single Flywheel
3683- Low Goal
5254 - Dual Wheel

Quarterfinalists 1
2771 - Single Flywheel
16 - Single Flywheel
1024 - Catapult
1023 - Single Flywheel

Quarterfinalists 2
217 - Single Flywheel
2451 - Catapult
494 - Single Flywheel
3641 - Dual Wheel

Quarterfinalists 3
2481 - Single Flywheel
330 - Linear Punch
3824 - Dual Wheel
1640 - Catapult

Quarterfinalists 4
45 - Catapult
179 - Single Flywheel
1806 - Linear Punch
233 - Low Goal

I am probably wrong somewhere in this list so if you see something wrong just PM me and Ill edit it.