Team Update 1-15-2013

[Basel A]

Originally Posted by Tristan Lall

¹ Don't use the frame perimeter. It's a trap. The definition allows for skew polygons and planar polygons not parallel to the floor.

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..

[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.

[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.

[Kevin Sevcik]

Originally Posted by 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.

Note that in the real world, engineering specifications are agreed to and contracted. When the client comes in later trying to change them drastically and invalidate the current design, there's usually deadline extensions, bills for the engineering change, etc.

[Nemo]

I'm surprised by this change since they already answered it in the opposite way previously. Better now than later, I guess, but this is a question that could have reasonably been anticipated and clarified before the game was released.

This didn't blow our climbing concept out of the water, but I'll be watching closely for a bumper clarification that has the potential to cause us trouble.

[efoote868]

Originally Posted by Kevin Sevcik

Note that in the real world, engineering specifications are agreed to and contracted. When the client comes in later trying to change them drastically and invalidate the current design, there's usually deadline extensions, bills for the engineering change, etc.

Usually not the case with your boss though.

[rsegrest]

Originally Posted by 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.

However, we are talking about teams who have limited budgets and who in some cases have sent out drawings etc. to be machined. Many of us do not have the money or resources to have parts remachined etc. Fortuntately for my team (whose design is now not legal) we had not ordered parts or sent out CAD drawings for machining and we may still have time to go back to the drawing board.

I agree with the others who call this a bad move and bad form on the part of the GDC especially when this was discussed completely in a mentor call and it directly contradicts an earlier answer in the formal Q&A (which is also hosted by the GDC).

[dellagd]

Has FIRST ever made such a big change like this before?

[Donut]

Originally Posted by dellagd

Has FIRST ever made such a big change like this before?

When the seeding algorithm was changed in 2010 is probably the biggest change ever during the season. I think it was a good change (gave incentive to win) but that is a huge change to have mid-season.

They've changed size dimensions before as well, I don't know if it's always been so critical to a task like this though.

[mrnoble]

Is it possible this rule change was more in response to concerns that robots that fall over would be in continuous violation, rather than concerns about complex climbing mechanisms? I know that was discussed as a concern at the beginning of the season.

Still stinks though, especially for cool ideas like some that have been spoiled now. Very sorry indeed, folks.

[Steve Kaneb]

I think the despair expressed in this thread might be premature.

The updated rule reads (in part):

Originally Posted by 2k13 FRC Manual

While in contact with the PYRAMID, a ROBOT

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

Nowhere in this rule do the words "in its starting configuration" appear. It's most likely that in any configuration where your robot can fit within a virtual 54" cylinder that extends "vertically", while still fulfilling the rules of robot height (not to exceed 84") and the rule about the vertical plane that extends from a line 54" from the pyramid, that your robot is legally within the volume limits.

I foresee a referee noting a possible infraction, then checking after the match by having the team reposition their robot as it was when he had doubts to its legality (even if it has to stand on a bumper!). Once the robot is in the configuration, a hoop is passed over the robot. If the hoop can be extended vertically without contacting the robot, the robot was legal.

[efoote868]

When you look at the rule change, it seems that the intent of the rule could be to prevent a team from latching on to the pyramid and then extending towards the side of the playing field, in order to attempt to blockade the field (circumventing the other rule?).

[chadr03]

Here is my interpretation of the new rule and how is kills our design that was so close to sending parts our to be machined. I hope the GDC changes its mind. Since in all likelihood this bot will not come to life in its current form I thought I would share.


Old Rules - Legal

New Rules - Illegal