Team Update 1-15-2013

[Tristan Lall]

Originally Posted by Basel A

Vertical is the normal to the plane of the ground relative to a robot on the ground at the start of the match. Besides, notice that flop-bots and unfolding bots haven't been used since the current era of bumpers (2009+). You could just use bumpers..

G23-1 mentions verticalness in relation to the robot. Barring the degenerate case where the entire robot is always in a fixed orientation with respect to the ground, that's proof that we can't use the ground as the sole co-ordinate reference.

In terms of using bumper edges as the reference, there are similar issues. The bottom edge of a legal bumper can (in theory) be between 2.0 in and 5.5 in from the ground, meaning significant angles are possible.

Edit: I re-read your post, and may have misunderstood it the first time. Are you suggesting that we construct the robot-relative co-ordinate system based on something like the the starting bumper orientation and the ground normal? (Hopefully the floor protector doesn't figure into this.) Then, because the bumpers can't articulate, we can use them to observe the orientation of the robot-relative co-ordinates during the climb? That has interesting implications (like when bumpers fall off), but could be feasible. However, I don't think the rules support this interpretation to the exclusion of others.

[Kusha]

So is this not legal now?

Excuse the crude drawing

[Bill_B]

It has been a long day with robots of plastic and aluminum at both ends. We're slow and were doing full-scale modeling to determine our compliance with 54" rule in its prior form. Now I read of the rules change and that several teams are feeling that their initial designs are now illegal. This is where the tired part comes in. I'm having trouble imagining how something legal for the vertical cylinder is now illegal for a tilted one. I'm sure those are right, just in a FRC fog at the moment I guess.

[dellagd]

Originally Posted by Kusha

So is this not legal now?

Excuse the crude drawing

Um, what exactly did you draw?

[Taylor]

Our design, our beautiful design, is in serious, serious question right now.
blog.
blarg.
ugh.
This.Inhales.Audibly.

[Kusha]

Originally Posted by dellagd

Um, what exactly did you draw?

Just a robot hanging on the first tier parallel with the ground.

[MetalJacket]

Originally Posted by Kusha

Just a robot hanging on the first tier parallel with the ground.

Unless you draw in some kind of dimensions for the robot, it's hard to say if it's legal or not. As long as no part of the robot exceeds a 54" diameter cylinder relative to the robot, you should be fine though.

[BigJ]

Originally Posted by Bill_B

It has been a long day with robots of plastic and aluminum at both ends. We're slow and were doing full-scale modeling to determine our compliance with 54" rule in its prior form. Now I read of the rules change and that several teams are feeling that their initial designs are now illegal. This is where the tired part comes in. I'm having trouble imagining how something legal for the vertical cylinder is now illegal for a tilted one. I'm sure those are right, just in a FRC fog at the moment I guess.

If your robot was cimbing up the outside of a leg (and was short), with your starting configuration parallel to the leg, you had a >54 inch long ellipse to reach/manipulate/etc with.

edit: just imagine slicing a plane through a vertical 54 inch cylinder at a 60 degree angle.

edit2: this is only one example

[Kusha]

Originally Posted by MetalJacket

Unless you draw in some kind of dimensions for the robot, it's hard to say if it's legal or not. As long as no part of the robot exceeds a 54" diameter cylinder relative to the robot, you should be fine though.

OH, I didn't notice it was relative to the robot! Never mind.

Didn't read this:

may not have its horizontal dimensions exceed a 54 in. diameter vertical cylinder relative to the ROBOT and

[yarudl]

Originally Posted by Taylor

Our design, our beautiful design, is in serious, serious question right now.
blog.
blarg.
ugh.
This.Inhales.Audibly.

I'm sorry, but to the best of my understanding that design is now illegal. I can sympathize as my team is in the same place as yours. Our design is now illegal as well.

[Djur]

I'm happy to say that my team's level 3 climber design is still legal

[Basel A]

Originally Posted by Tristan Lall

G23-1 mentions verticalness in relation to the robot. Barring the degenerate case where the entire robot is always in a fixed orientation with respect to the ground, that's proof that we can't use the ground as the sole co-ordinate reference.

In terms of using bumper edges as the reference, there are similar issues. The bottom edge of a legal bumper can (in theory) be between 2.0 in and 5.5 in from the ground, meaning significant angles are possible.

Edit: I re-read your post, and may have misunderstood it the first time. Are you suggesting that we construct the robot-relative co-ordinate system based on something like the the starting bumper orientation and the ground normal? (Hopefully the floor protector doesn't figure into this.) Then, because the bumpers can't articulate, we can use them to observe the orientation of the robot-relative co-ordinates during the climb? That has interesting implications (like when bumpers fall off), but could be feasible. However, I don't think the rules support this interpretation to the exclusion of others.

I did not spend as much time explaining my post as I could or should have, but you got the idea in your reread. I'm certainly not suggesting this is what's reflected in the current manual, but I do think this is would give results equivalent to both "common sense" and the likely interpretations of most referees. I'd challenge you or anyone else to suggest a potential rule that would be feasible and would contradict the the bumper-based model.

Note: Haven't figured out the rule that says bumpers must be "vertical." R24-E comes close, but doesn't quite do it.

[MetalJacket]

Originally Posted by Basel A

I did not spend as much time explaining my post as I could or should have, but you got the idea in your reread. I'm certainly not suggesting this is what's reflected in the current manual, but I do think this is would give results equivalent to both "common sense" and the likely interpretations of most referees. I'd challenge you or anyone else to suggest a potential rule that would be feasible and would contradict the the bumper-based model.

Note: Haven't figured out the rule that says bumpers must be "vertical." R24-E comes close, but doesn't quite do it.

The issue of level bumpers has been brought up in the Q&A. The bumpers do not necessarily need to be level so long as they are completely within the bumper zone (I believe 971 did this last year). So the bumpers won't necessarily be a perfect measure of normal to the robot, but given the variation in height possible while staying in the bumper zone, it's pretty close.

[efoote868]

I'm not trying to look flippant, but in the real world engineering specifications change all the time.
FRC: more like the real world than we could ever want.

[Donut]

Originally Posted by Taylor

Our design, our beautiful design, is in serious, serious question right now.
blog.
blarg.
ugh.
This.Inhales.Audibly.

I feel your pain. If we do climb our strategy likely involved flipping our frame off of the floor to give us a fairly long reach. Now I'm about 95% certain that design is illegal, I will have to do the math. It may be adaptable by rotating our frame relative to our climbing mechanism but it will almost certainly put our CG in an undesirable location.

This is a disappointing ruling from the GDC. Major changes like this shouldn't be necessary to the size restrictions, which are some of the most crucial rules teams have to design around. Coming in week 2 as teams are finishing prototypes and some have begun ordering parts is the real kicker.