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-   -   WEEK 1 (http://www.chiefdelphi.com/forums/showthread.php?t=104131)

KrazyCarl92 03-03-2012 23:10

Re: WEEK 1
 
Stats from GSR (comprehensive match scouting): 30/50 teams scored in hybrid
18 teams scored in the top, 28 in the middle, and 9 in the low
Teams who shot a considerable number of balls, accuracy ranged from 0 to 83%
28 teams balanced at some point
some inbounders are really really bad...

Fender scoring dominates quals because few ranged shooters can keep up. And no one played defense consistently, which made for a very very boring game.

I hated Rebound Rumble, until I saw teams 1519, 885, and 2791 play in eliminations. It was boring; no defense, and all the matches were the same. They played the best defense as an alliance I have ever seen in an FRC game. If 2791 kept working, they win the regional in DOMINANT fashion. Their gameplay showed how STRATEGY aligned with good robots that fit a strategy can win matches against teams they are "overpowered" against. Hybrid is super important, both scoring and getting balls from the bridge as fast as possible.

Defensive robot is the most valuable robot on the field, which makes the ability to shoot from the key AND the fender important. If you can't access one, go to the other. Exclusively fender scorers may get a false sense of dominance if there continues to be a lack of defense in the quals.

Also balls that are worn down go much shorter than competition quality balls. The bane of Team 20....turned a 60% shooter into a 3-basket-the-entire-tournament atrocity. It was repeatably about 3-4 feet high, but we have plans for easy adjustment at future events, and also to shoot from the fender :). Bridges are much harder to push down than FIRST's battery test implies.

cire 03-03-2012 23:26

Re: WEEK 1
 
Quote:

Originally Posted by KrazyCarl92 (Post 1138409)
Stats from GSR (comprehensive match scouting): 30/50 teams scored in hybrid
18 teams scored in the top, 28 in the middle, and 9 in the low
Teams who shot a considerable number of balls, accuracy ranged from 0 to 83%
28 teams balanced at some point
some inbounders are really really bad...

Fender scoring dominates quals because few ranged shooters can keep up. And no one played defense consistently, which made for a very very boring game.

I hated Rebound Rumble, until I saw teams 1519, 885, and 2791 play in eliminations. It was boring; no defense, and all the matches were the same. They played the best defense as an alliance I have ever seen in an FRC game. If 2791 kept working, they win the regional in DOMINANT fashion. Their gameplay showed how STRATEGY aligned with good robots that fit a strategy can win matches against teams they are "overpowered" against. Hybrid is super important, both scoring and getting balls from the bridge as fast as possible.

Defensive robot is the most valuable robot on the field, which makes the ability to shoot from the key AND the fender important. If you can't access one, go to the other. Exclusively fender scorers may get a false sense of dominance if there continues to be a lack of defense in the quals.

Also balls that are worn down go much shorter than competition quality balls. The bane of Team 20....turned a 60% shooter into a 3-basket-the-entire-tournament atrocity. It was repeatably about 3-4 feet high, but we have plans for easy adjustment at future events, and also to shoot from the fender :). Bridges are much harder to push down than FIRST's battery test implies.

Thanks for the stats, this year seems to have a pretty high percentage of autonomous scoring teams relative to other years. This may be because the fact that you don't need to drive anywhere to try for a point in autonomous though.

Can you (or anyone) elaborate on the "competition quality" balls? Were all the balls the same, or did they vary much like a lot of teams reported on these forums during build? Were they all more firm, non deflated? At what point did they replace the balls, if at all?

Thanks!

Deetman 04-03-2012 00:28

Re: WEEK 1
 
Quote:

Originally Posted by cire (Post 1138417)
Can you (or anyone) elaborate on the "competition quality" balls? Were all the balls the same, or did they vary much like a lot of teams reported on these forums during build? Were they all more firm, non deflated? At what point did they replace the balls, if at all?

Thanks!

From my viewpoint observing in the stands, the "quality" of the balls in play generally seemed to exhibit general wear and tear akin to what teams noticed during build season. At Hatboro-Horsham it appeared that if a ball was largely intact (no significant divots or gouges) it was used. If a ball sustained significant damage it was removed from play after the match. I know I saw at least two ball-hats.

2018 (HH winning alliance, 2nd seed) had a unique system on their robot that measured the compression of the balls and adjusted their shooter accordingly. Talking with someone in their pits, their testing showed that a 10% variability in compression could result in shot variances of 10 feet.

Andrew Lawrence 04-03-2012 00:34

Re: WEEK 1
 
Quote:

Originally Posted by Deetman (Post 1138450)
From my viewpoint observing in the stands, the "quality" of the balls in play generally seemed to exhibit general wear and tear akin to what teams noticed during build season. At Hatboro-Horsham it appeared that if a ball was largely intact (no significant divots or gouges) it was used. If a ball sustained significant damage it was removed from play after the match. I know I saw at least two ball-hats.

2018 (HH winning alliance, 2nd seed) had a unique system on their robot that measured the compression of the balls and adjusted their shooter accordingly. Talking with someone in their pits, their testing showed that a 10% variability in compression could result in shot variances of 10 feet.

How'd they measure it?

ThirteenOfTwo 04-03-2012 00:35

Re: WEEK 1
 
I'l try to only add things that I didn't see mentioned yet in this thread.

Seeding rounds were being really boring because no one was playing defense, but I saw a lot of teams playing in ways that were just completely wrong. There was one team in San Diego who failed to balance on the coopertition bridge, so they went over, touched the opposing alliance's bridge (a nine-point technical foul), and then drove away and ended the match. I don't know if it hasn't sunk in yet, but your opponent's score this year DOES NOT MATTER. Especially if you have robots in your alliance that can't score, it is in your interest to win matches in qualifiers by playing defense! A lot of teams have some really weird ideas about seeding this year...

Two teams in San Diego had my favorite idea of the week--the 2v2 Qualification Match. At the beginning of the match, they sent one team from each alliance, neither of whom looked like they could score, to the coopertition bridge to lock down the bonus points. That's a terrific idea. The coopertition bridge is hard, and you need a lot of time to get on it... what is a robot that can't score going to do that's worth more than 2 QP?

KrazyCarl92 04-03-2012 01:44

Re: WEEK 1
 
Our team sank 60% our shots in practice at our field in the top basket. Competition field, in the 7 matches out of 10 we were mechanically okay we shot around 4-8 shots per match and sank 3 all tournament, shooting almost all of our misses 3-4 feet high. The worn out balls squish easier than the ones on the field I believe (trusting the word of my drivers who felt both balls, and the physics that make sense). Our targeting system is unaffected by lighting changes from practice field to field, as evidenced by saving images to the cRio in match to check to see if that was the problem.

The physics behind this makes sense. If a ball is squisher, it will compress more easily. Since less force is needed to compress it, it will mean less normal force between the wheels and the ball, less frictional force, and less speed coming out. A firmer ball will take more force to compress to the same dimension, which means more normal force, and therefore friction, between the ball and the wheel leading to an increase in muzzle velocity. We're fairly certain the angle of our shooter didn't vary from practice field to competition, so the only thing is speed...which we can only attribute to the balls. We went to the practice field at competition and used our own balls (worn out and squishy) to shoot, no problems! So we need to find some way to account for that discrepancy.

picture of our robot: http://www.chiefdelphi.com/media/photos/37578

davidthefat 04-03-2012 01:47

Re: WEEK 1
 
Wait, does this mean that our robot with 14 inch wheels, a terrible kicker and a bridge lowering mechanism actually has a chance this year? I balance solo in 4 seconds, two bots in about 15 to 30, depending on the other driver. For pete's sake, we have a KICKER... Let's just say I'll focus on defense.

KrazyCarl92 04-03-2012 01:50

Re: WEEK 1
 
Quote:

Originally Posted by davidthefat (Post 1138485)
For pete's sake, we have a KICKER... Let's just say I'll focus on defense.

Defensive robots are very effective, so don't worry. Sounds like you play the bridge great. Scoring in auto is huge, so at least try to do that, even if in the low basket. Also, if said kicker could clear some balls while playing effective defense (e.g. between pins), then you could be a GREAT eliminations partner.

Hebrew 04-03-2012 02:19

Re: WEEK 1
 
So a good strategy for a defensive robot seems to be just parking up at the fender to stop dumping robots?

Where would be the best place to balance at if our robot is only 90 pounds including battery?

Any other good defensive strategies for a team that has no shooter, just an arm to lower/raise the bridge, I am interested since our team has never been to a competition before :eek:

ThirteenOfTwo 04-03-2012 03:08

Re: WEEK 1
 
Quote:

Originally Posted by Hebrew (Post 1138496)
So a good strategy for a defensive robot seems to be just parking up at the fender to stop dumping robots?

Where would be the best place to balance at if our robot is only 90 pounds including battery?

Any other good defensive strategies for a team that has no shooter, just an arm to lower/raise the bridge, I am interested since our team has never been to a competition before :eek:

Can you hold balls so that you can ferry them from one side of the field to another? If not, then crossing the bridge to play defense at the beginning of the match is the best possible idea, but make absolutely sure that you don't get any penalties. See if you can write autonomous code to lower the bridge in the center of the field.

Koko Ed 04-03-2012 04:28

Re: WEEK 1
 
Quote:

Originally Posted by SenorZ (Post 1138056)
I've learned (from watching streams) that there are a lot of teams that are struggling.

this.:(

RufflesRidge 04-03-2012 08:17

Re: WEEK 1
 
Quote:

Originally Posted by Hebrew (Post 1138496)
Where would be the best place to balance at if our robot is only 90 pounds including battery?

Directly above the extra 40lbs of ballast I would recommend bolting onto your robot at the competition. From observation it is very difficult to balance 2 if the second one is light, as the first bot moves up the bridge to give the second space, the light bot isn't heavy enough to hold it down so it starts to tilt and they flip, even when the 2 robots stay very close together.

SciBorg Dave 04-03-2012 10:30

Re: WEEK 1
 
During week 1 many teams had a problem tipping the bridge. This made me think how many teams added the needed 200 pounds of weight to there practice bridges. We found that the added 200 pounds made the bridge much hard to tip. I saw 1 teams arm bend when they tried to tip the bridge.
It also seem that many team practice tipping with out the bumpers on, when the arm came down the bridge got caught between the bumper and the arm.

flippy147852 04-03-2012 10:41

Re: WEEK 1
 
Quote:

Originally Posted by SciBorg Dave (Post 1138586)
During week 1 many teams had a problem tipping the bridge. This made me think how many teams added the needed 200 pounds of weight to there practice bridges. We found that the added 200 pounds made the bridge much hard to tip. .

A lot of teams at Gull Lake were trying to tip the ramps with a window motor, and it just wasn't cutting it. They needed a lot more pushing force to tip the bridge.

pfreivald 04-03-2012 11:18

Re: WEEK 1
 
:ahh: We didn't add anywhere close to 200 pounds... I think we added 120 -- but we used the battery test as indicated on the field tour videos.

Here's hoping!


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