Team update 3/6/2012

[Tom Line]

Originally Posted by Marc S.

I noticed that they didn't address 118's hanging mechanism at all. I know the head ref at Alamo presented a statement but the GDC can't expect everyone to have heard that.

The GDC will never state that XXX's robot is illegal to all the other teams. They state the rules, and will evaluate them on a case by case basis at the events.

[BrendanB]

I'm glad to see this change after competing in week 1. Balls under the bridge definitely added challenge to the game play but it was a challenge we all knew was coming. I think FIRST has done a great job with the bridges as there is only so much they can simulate (after competing at a FIRST scrimmage balls and bridges weren't a noticeable issue because bridge play was not as common) but they did a great job with the ramps to keep balls from getting stuck far back. This change should really improve the huge number of balls that don't have enough inertia to get stuck and come to rest at the bottom of the lexan plate just enough to interfere with the bridge.

Thanks FIRST!

[Hadi379]

I might be mistaken, but are the drawings conflicting in terms of how the ball ramp is mounted below the bridge? If you look at drawing GE-12017, compare the way the ball ramp is mounted in sheet 1 & 2. Which one is correct or am I not seeing something?

[thefro526]

Originally Posted by Hadi379

I might be mistaken, but are the drawings conflicting in terms of how the ball ramp is mounted below the bridge? If you look at drawing GE-12017, compare the way the ball ramp is mounted in sheet 1 & 2. Which one is correct or am I not seeing something?

I noticed the same thing. If you look at the Rev Level, Sheet 1 is Rev A while sheets 2, 3 and 4 remain at their base revision. In this case Sheet 1 would take precedent over the others.

Also, for anyone who doesn't want to go through the hassle of opening up the field drawings, here is a screen shot of the drawing that shows the relevant changes. (Please excuse the size)

[Retired Starman]

Originally Posted by thefro526

I noticed the same thing. If you look at the Rev Level, Sheet 1 is Rev A while sheets 2, 3 and 4 remain at their base revision. In this case Sheet 1 would take precedent over the others.

Also, for anyone who doesn't want to go through the hassle of opening up the field drawings, here is a screen shot of the drawing that shows the relevant changes. (Please excuse the size)

The change makes two improvements in the ramp. First, the polycarbonate ramp has been turned over and the aluminum angle, which was below the ramp has been removed. This makes the angle of the ramp steeper and it will bet even steeper when the bridge is pushed down. Look at GE-12064 to see that the aluminum angle has been removed. This drawing shows the polycarbonate upside down, guess FIRST didn't want to take time to flip it. GE-12017 page 1 shows the new orientation of the ramp. As before, the ramp is pulled up tight under the bridge.

This will help some, but the polycarbonate just isn't rigid enough and will continue to sag down to the edge of the bridge. What would really help is some edge strip to hold the polycarbonate straight.

Dr. Bob

Chairman's Award is not about building the robot. Every team builds a robot.

[coldfusion1279]

Glad to see they made a change. In elimination matches, alliances were losing because there happened to be balls under their ramps and they could not get on; either intentionally placed by the opposing alliance, or balls just happened to roll under.

[martin417]

Originally Posted by Retired Starman

...This will help some, but the polycarbonate just isn't rigid enough and will continue to sag down to the edge of the bridge. What would really help is some edge strip to hold the polycarbonate straight.

Dr. Bob

Chairman's Award is not about building the robot. Every team builds a robot.

I watched some of the webcasts as well as some youtube videos later on. It appears that you are correct in that the polycarb is not rigid enough. If you look closely at the bridges, the polycarb seems to lie flat on the floor for most of its length, so it has no slope. If they were to add a small aluminum angle to each side, oriented upwards, it would help immensely. Maybe the increase in initial slope will help. We will have to wait for week two.

[Cal578]

Originally Posted by Retired Starman

...This makes the angle of the ramp steeper and it will bet even steeper when the bridge is pushed down. ...

How does the ramp get steeper when the bridge is pushed down? It looks to me like the ramp is mounted to non-moving parts.

[Nate Laverdure]

Originally Posted by Cal578

How does the ramp get steeper when the bridge is pushed down?

I believe Starman is referring to the ball deflector when talks about the "ramp." That is, with this update, the ball deflector has been rotated so that it's at a steeper angle with respect to the floor.

EDIT: Er, nevermind... you already understood that. He's saying that when the bridge is pushed down, the underside of the bridge contacts the ball deflector and pushes it down as well.

[Cal578]

Originally Posted by Nate Laverdure

...when the bridge is pushed down, the underside of the bridge contacts the ball deflector and pushes it down as well.

I'm not sure the bridge is going to push the ramp (or ball deflector) down in such a way as to make it steeper. Even if it does, if there's a ball in there that hasn't come out yet, the ball will get stuck between the bridge and the ramp, no matter how steep the ramp is or how it might change.

My point is just that all the improvement of the new assembly comes from it being steeper while the bridge is up, hopefully getting balls out before the bridge comes down.

[martin417]

Originally Posted by Nate Laverdure

....He's saying that when the bridge is pushed down, the underside of the bridge contacts the ball deflector and pushes it down as well.

Actually, the ball deflectors are tied to the bridge with a length of small diameter wire rope. When the bridge is pushed down on one side, the other side is lifted up. Since the ball deflector is tied to it, the ball deflector on the high side is lifted also, increasing the angle. See this video: at about 52 seconds.

[Nate Laverdure]

Originally Posted by martin417

When the bridge is pushed down on one side, the other side is lifted up.

Ah, that makes more sense. Thanks!

[JamesCH95]

Originally Posted by martin417

I watched some of the webcasts as well as some youtube videos later on. It appears that you are correct in that the polycarb is not rigid enough. If you look closely at the bridges, the polycarb seems to lie flat on the floor for most of its length, so it has no slope. If they were to add a small aluminum angle to each side, oriented upwards, it would help immensely. Maybe the increase in initial slope will help. We will have to wait for week two.

Maybe for some teams, but the angle would be obliterated by robots like ours that can quite easily tip the bridge away and clean out balls from underneath it.

I think it would be very unfair to teams like mine who solved the original problem but would run a serious risk of 'damage to playing field' penalties if the field element design was changed radically.

We took the mentality that it was just another challenge to overcome and another feature to set our robot apart. I'll admit I'm a little disappointed with the change because it takes an advantage away from teams like ours that worked hard to have that extra capability.

/mild rant

[martin417]

Originally Posted by JamesCH95

Maybe for some teams, but the angle would be obliterated by robots like ours that can quite easily tip the bridge away and clean out balls from underneath it.

I think it would be very unfair to teams like mine who solved the original problem but would run a serious risk of 'damage to playing field' penalties if the field element design was changed radically.

We took the mentality that it was just another challenge to overcome and another feature to set our robot apart. I'll admit I'm a little disappointed with the change because it takes an advantage away from teams like ours that worked hard to have that extra capability.

/mild rant

Except that was not stated intent of the GDC. The Bridge was designed so that balls could be removed by pushing the bridge down on the opposite side. The bridge did not function as designed and published at the beginning of the season. The change was made to try to correct this flaw. Had the GDC not published the ball deflector as a means of ball clearing, both in the field drawings and the Field tour video, you might have a point.

[JamesCH95]

Originally Posted by martin417

Except that was not stated intent of the GDC. The Bridge was designed so that balls could be removed by pushing the bridge down on the opposite side. The bridge did not function as designed and published at the beginning of the season. The change was made to try to correct this flaw. Had the GDC not published the ball deflector as a means of ball clearing, both in the field drawings and the Field tour video, you might have a point.

What I saw at both the Week 0 and the Week 1 was balls that the ball deflector worked on balls that were stuck reasonably far under the bridge, as depicted in the field tour video. However, balls that were near the very end of the ramp would not roll out, as might be reasonably expected because the lexan is supposed to be taped down by its edge. Even with the change is still impossible to tip out balls that are only partly under the bridge.

It might be that some fields (and even different bridges on the same field) were setup slightly differently and therefore behaved differently and that you and I merely have different observations.