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-   -   Ball bouncing out of the high Goal (http://www.chiefdelphi.com/forums/showthread.php?t=142056)

Ben Wolsieffer 05-04-2016 21:21

Re: Ball bouncing out of the high Goal
 
We also ran into problems with balls bouncing out of the high goal, and for us it always happened the same way.

If we lined up just to the right of the center goal (the same thing would probably happen from the the left of the goal), the ball would hit the back corner and bounce out the right goal. I believed this happened three times in Boston, and it caused us to lose our first quarterfinal match when it bounced out during auto. This video shows what happened.

Andrew Schreiber 05-04-2016 21:31

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by danieh65 (Post 1568252)
At the very least, it would be helpful if FIRST increased the amount or mass of the chains so that this would not happen as often. While we have been considering lowering the power of our shooter so that this does not happen as often, it just seems logical to ensure that shots made in the high goal are counted as accurately as possible. In the last competition, 107 experienced this issue recurrently, sometimes occurring up to three times in a single match.

Quote:

A BOULDER is scored in a GOAL if it passes through the opening of a GOAL and exits into the CORRAL.
FIRST is correctly counting scored BOULDERS. You are simply not scoring them because they are not exiting into the CORRAL. Field is working as designed and spec'd.

Wayne TenBrink 05-04-2016 22:07

Re: Ball bouncing out of the high Goal
 
I wish FIRST had modified the goals to reduce or eliminate bounce-outs early in the season. I think it is a bit late to do it now. Although the definition of a "scored boulder" addresses bounce-outs, I really hope that FIRST didn't intend to see this many. In an ideal world, you get credit for putting the boulder in the goal and not just for doing it with some preferred trajectory.

We have struggled with bounce-outs, but of a different sort. We shoot a high angle shot from the batter (like a lot of other teams), and unless we hit the top of the window, the backspin on the ball makes it roll down the chains, bounce off the framing at the bottom of the angled face of the castle, and then out.

scca229 05-04-2016 22:39

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by lopsided98 (Post 1568254)
We also ran into problems with balls bouncing out of the high goal, and for us it always happened the same way.

If we lined up just to the right of the center goal (the same thing would probably happen from the the left of the goal), the ball would hit the back corner and bounce out the right goal. I believed this happened three times in Boston, and it caused us to lose our first quarterfinal match when it bounced out during auto. This video shows what happened.

Just watching the auto shot that didn't stay in, I can see that your robot fires pretty hard. Does it also fire with a significant horizontal spin? The resolution of the video doesn't let me see if the boulder even touches the chains at all, or just hits the opposite inside of the tower and then runs along the back plastic and comes out. The chains are there to absorb some of the energy of the boulder and attempt to keep the boulder from coming in one side and bouncing out the other or coming into the center and bouncing off the back right out the center again.

My unscientific observation, after watching 314 Qual/Elim matches and ~100 practice matches field-side, is that a very hard shot causes the chains to not have time to move or absorb and actually act as a solid wall. More mass would actually cause that particular action to occur more than it does. They need to have some mass, or the boulder is going to blast right through them, but too much and they don't move at all.

That missed shot wasn't what solely lost the match. After auto, you spent 23 seconds hung up on an alliance partner and then fired two high goal shots off of the tower facade (with one low goal in between). The red alliance also missed an auto shot on high goal. Two blue robots rolled off the batter at the end. Red alliance "should" have had a capture if one bot hadn't gotten stuck on the moat. Red also fully depleted the tower but didn't breach the defenses, which I can't think I have seen first hand in any of the 3 events I've FTA'd. The score (individually and combined) for the match was a good deal lower than the 2nd match of the series. Both alliances had a cavalcade of errors to point to for how it was lost and won.

philso 05-04-2016 22:44

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by Wayne TenBrink (Post 1568271)
I wish FIRST had modified the goals to reduce or eliminate bounce-outs early in the season. I think it is a bit late to do it now. Although the definition of a "scored boulder" addresses bounce-outs, I really hope that FIRST didn't intend to see this many. In an ideal world, you get credit for putting the boulder in the goal and not just for doing it with some preferred trajectory.

We have struggled with bounce-outs, but of a different sort. We shoot a high angle shot from the batter (like a lot of other teams), and unless we hit the top of the window, the backspin on the ball makes it roll down the chains, bounce off the framing at the bottom of the angled face of the castle, and then out.

Have you considered reducing the amount of back-spin you are imparting on the Boulder.

In the real world, you get credit for finishing the job you are asked to do. In this case, your true objective is not really to get the Boulder to enter the opening of the Goal. It is to get the Boulder to trip the Counting Mechanism that is several feet below the opening of the Goal.

As Andrew stated, "Field is working as designed and spec'd." This means that certain solutions will work successfully and others will not. It is up to those competing in this game to find the solutions that do work.

pntbll1313 05-04-2016 23:03

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by philso (Post 1568291)
Have you considered reducing the amount of back-spin you are imparting on the Boulder.

In the real world, you get credit for finishing the job you are asked to do. In this case, your true objective is not really to get the Boulder to enter the opening of the Goal. It is to get the Boulder to trip the Counting Mechanism that is several feet below the opening of the Goal

We use a catapult and using our slow motion camera we have almost 0 back spin. We throw it just as hard as we need to in order to have a large sweet spot. Watch our robot's autonomous (low bar blue robot). Sometimes the chains just act like a swing and spit you right back out despite your design. It's almost comical how it spits it right back out at us haha.

CalTran 05-04-2016 23:23

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by pntbll1313 (Post 1568297)
We use a catapult and using our slow motion camera we have almost 0 back spin. We throw it just as hard as we need to in order to have a large sweet spot. Watch our robot's autonomous (low bar blue robot). Sometimes the chains just act like a swing and spit you right back out despite your design. It's almost comical how it spits it right back out at us haha.

I mean, isn't that a result of the trajectory for a catapult? It throws it hard and somewhat flat directly at the bottom of the chains. It's physics that the ball swings with the chain and continues out when the chains gets pulled back.

philso 05-04-2016 23:31

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by pntbll1313 (Post 1568297)
We use a catapult and using our slow motion camera we have almost 0 back spin. We throw it just as hard as we need to in order to have a large sweet spot. Watch our robot's autonomous (low bar blue robot). Sometimes the chains just act like a swing and spit you right back out despite your design. It's almost comical how it spits it right back out at us haha.

That's kind of like playing miniature golf with the wacky obstacles such as having to hit the ball through the spinning blades of a windmill. I seem to recall someone shooting a boulder in the high goal on one side and it came out the goal on the other side.

Jeremy Germita 06-04-2016 01:32

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by CalTran (Post 1526043)
At least this year it's really difficult to overfill the goal. I'm interested to see the return of the pokey stick from 2012.

There were a couple of matches at Vegas where balls would accumulate on the shelf inside of the goal. After the first occurrence, volunteers would be behind the tower waiting with the stick used to haul defenses around. These matches were definitely fun to watch.

Tom Line 06-04-2016 02:00

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by philso (Post 1568309)
That's kind of like playing miniature golf with the wacky obstacles such as having to hit the ball through the spinning blades of a windmill. I seem to recall someone shooting a boulder in the high goal on one side and it came out the goal on the other side.

This happened several times to several different teams at FiM Troy. It's not much different than 2014, when balls would sometimes come back, and 2013, when frisbees were routinely ejected.

Roger 06-04-2016 06:59

Re: Ball bouncing out of the high Goal
 
I've seen boulders shoot in one side upper goal and come out the other. I didn't know what to do at first, but the Refs do.

One thing I did, as a corral keeper, is make sure the boulders rolled thru the counter boxes once inside. If they got stuck in the upper goal, we have a pokie-stick to bring them down in the chutes. If there is boulders in the way for the lower goals, I'd make room for the chute.

However, if a Human Player (teams to remain nameless) leaves a dozen or more boulders in the corral (yeah :ahh: !), blocking any more to come in, well, I tried my best to get them scored.

Watching from the inside the goals, as it were, for the bottom goals I had the sensation of a pack of dogs shoving balls into my mouse hole (okay, bad mixed metaphor) or being inside someone's mouth while they are eating.

Maximillian 06-04-2016 08:15

Re: Ball bouncing out of the high Goal
 
The strangest missed shot we had was when our spy bot shot went in the side goal and then bounced out the front.

pntbll1313 06-04-2016 10:27

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by CalTran (Post 1568305)
I mean, isn't that a result of the trajectory for a catapult? It throws it hard and somewhat flat directly at the bottom of the chains. It's physics that the ball swings with the chain and continues out when the chains gets pulled back.

Yep. My response was in reply to someone suggesting backspin may be the culprit.

Quote:

Originally Posted by philso (Post 1568309)
That's kind of like playing miniature golf with the wacky obstacles such as having to hit the ball through the spinning blades of a windmill.

At the time our high goal autonomous was inconsistent. That 1 second period where we though we made the shot made us feel like this after it spit it back out.

Richard Wallace 06-04-2016 11:31

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by Maximillian (Post 1568386)
The strangest missed shot we had was when our spy bot shot went in the side goal and then bounced out the front.

This is just absurd, and easily corrected.*
Quote:

Originally Posted by pntbll1313 (Post 1568427)
... At the time our high goal autonomous was inconsistent. That 1 second period where we thought we made the shot made us feel like this after it spit it back out.

This is the real issue. We who participate in the technical challenge can appreciate the subtleties of scoring rules, but to the proud grandmothers and their friends in the general audience, which I sincerely hope FIRST is still trying hard to grow, not crediting an oddball just looks ridiculous.

-------
*One possible method: Head Ref and neutral zone ref are busy watching for G13 and other miscues, outer works refs are busy scoring auton crossings and reaches -- that leaves courtyard refs free to watch for oddballs like this one, and notify Head Ref so that the score missed by tower sensors can be entered manually.

Anthony Galea 06-04-2016 11:45

Re: Ball bouncing out of the high Goal
 
Quote:

Originally Posted by Richard Wallace (Post 1568461)
*One possible method: Head Ref and neutral zone ref are busy watching for G13 and other miscues, outer works refs are busy scoring auton crossings and reaches -- that leaves courtyard refs free to watch for oddballs like this one, and notify Head Ref so that the score missed by tower sensors can be entered manually.

Then the problem becomes an issue of keeping track of the 'scored' balls on the field so they aren't scored twice.


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