pic: Is this corner considered protected?

[Scott Hill]

EricH,

I believe the statements you included were referencing the sides of the corner.

Thanks,

Scott

[EricH]

Originally Posted by Scott Hill

EricH,

I believe the statements you included were referencing the sides of the corner.

Thanks,

Scott

In which post?

The debate here (to remind ourselves and inform anyone just joining us) is over one simple question: Do both sides of a given corner have to be protected by bumper segments of 6" or more?

I am going to state the full reason for my interpretation. This will take a while, so bear with me.

My response will follow the reverse chronological order in Q&A.

http://forums.usfirst.org/showthread.php?t=11635

3 rules are cited. One is hard parts in a corner, one is the backing. Those aren't relevant here. But the reference to <R08-A> is interesting. Rounding a corner to protect both sides results in 2 segments. Neither is long enough in this case.

The next one regards the design under consideration. http://forums.usfirst.org/showthread.php?t=11600
However, it only covers defining an exterior corner.

http://forums.usfirst.org/showthread.php?t=11609 Clarification that no, you can't wrap a bumper and have it be one segment. From henceforward, I will ignore those Q&As that cover this topic, unless something else is answered.

http://forums.usfirst.org/showthread.php?t=11454
They are considering a similar setup. Note that the GDC says, "We can't rule on specific designs. We leave that to the event inspectors."

http://forums.usfirst.org/showthread.php?t=11471
This one is annoying. It references Bill's Blog and sets off a chain of research. Ah-hah! Bill's Blog has something: http://frcdirector.blogspot.com/2009...r-musings.html
Unfortunately, this is an unofficial channel. Nonetheless, point 3 is important. Remember, Bill is on the GDC. This is by no means official, however. I will deal with the rest of the research later, if necessary.

OK, I lie. This one is referenced to ask the previous question. http://forums.usfirst.org/showthread.php?t=11170
Note: the relevant question, #1 in the second post, is not directly answered. However, the logic is confirmed.

http://forums.usfirst.org/showthread.php?t=11218 is perhaps the most direct. See the GDC's first paragraph. This is one disagreed with earlier. I will simply say, note the plural.

http://forums.usfirst.org/showthread.php?t=11159 is also referenced by the one that references Bill's Blog, though through a chain. #2 is the relevant point here. It's another "answer with a not-quite answer".

http://forums.usfirst.org/showthread.php?t=11056 Here's one for you. They say that at least part of the fourth side of a 4-sided robot must be covered by bumpers. If that holds with an extra 2 sides...

http://forums.usfirst.org/showthread.php?t=10933 and http://forums.usfirst.org/showthread.php?t=11070 address the issue directly and are vaguely answered, at least as concerns this discussion.

Those are all that I could find relating to this topic. Taking those together, I conclude that the corners A and B must have a 6" segment of bumper on both sides, which is impossible due to the location of the trailer hitch. Therefore, a design change must be made. If there are questions as to why I interpret a response the way I do, go ahead and ask; I could be wrong.

Edit: Dave responded in the thread with just the overhead view. His response (barring an official overturning from the GDC via Q&A) is that the configuration won't pass inspection.

[Tristan Lall]

Originally Posted by Scott Hill

Each side of the corner, side AB and side FA, is protected by BUMPERS. Each sides protection clearly meets the intent of <R08> ..."If implemented as intended, a ROBOT that is driven into a vertical wall in any normal PLAYING CONFIGURATION will always have the BUMPER be the first thing to contact the wall."... . Side AB has no BUMPERS on it yet the BUMPER configuration clearly meets the intent of the rule, which is clearly stated.

It looks like you're suggesting that any bumper design that satisfies the condition in the intent statement offers the required protection. That's not unreasonable, but I don't think that's the way that the GDC understands it.

As a test case for your theory, consider a robot similar to the one you posted above. Move the trailer hitch out of the way (put it in the gap on DE). Delete the section AB. Extend the segments FA and BC to their intersection, and call it G (but leave the bumpers as-is). Delete points A and B, leaving us with rigid segments GC and FG. Now, if we perform those operations on the picture above, we end up with a big sharp corner (at G) that clearly extends beyond the bumpers. This contravenes the condition in the intent statement, and is not protected by segments. But what if we made the angle at G something large, like 170°? There is still a corner (a discontinuity in the radius of curvature), but now the thickness of the existing bumpers allows it to pass the intent statement's condition (the corner doesn't stick out past the outermost edges of the bumpers anymore).

Is it your contention that even though the 170° corner at G is not abutted by any bumper segments, all necessary conditions are met (because the bumper hits first), and it would therefore be legal? If that's the case, then the amount of protrusion (inward or outward) past the edge of the bumpers is the most critical factor in determining protection (under your theory).

Apparently, the GDC considers the condition in the intent statement and the corner protection requirement to be separate, necessary conditions. Furthermore, it looks like they understand corner protection to mean a design with a legal bumper segment on each side of the corner.

Assuming that the function of the Q&A is to guide the interpretation of rules, but not to impose additional constraints*—that being the function of the rules and updates—the GDC's responses regarding corners have been mutually consistent and legal under the rules—so following them precisely ought to be acceptable at any event. (That's your best course of action.)

There might be some room for your interpretation, however: the GDC is describing a legal way to meet an existing requirement (protection of corners per <R08>, part I), but there's nothing in a rule or update that says that this is the only possible way to protect a robot's corners—in fact, to say that there is only one legal mode of protection (without some sort of explicit definition in the rules) is a bit of a stretch of the principle that the Q&A shouldn't be defining new constraints. (Yet, I think that that's implied here.) So as I understand it, you're relying on the fact that the next best thing to a direct definition of protection is the intent statement, and that because your proposed design passes that test, your corners are protected.

Like I said, it's not unreasonable...but you're taking a big risk that the inspectors at any given event will be open to considering that logic, and will arrive at the same conclusion as you, and that FIRST won't clarify things once and for all in an update (ruling against you).

*FIRST has not stated this directly for a couple of years, but that was formerly the rule of precedence. Maybe they made the statements in the 2009 Q&A binding, but neglected to tell anybody....

[SteveGPage]

Originally Posted by waialua359

I agree with this one. There will be many headaches for inspectors and some very unhappy campers on both sides.

The most simplest solution, while it may not allow teams to be as creative as they wanted to be, is to have a frame, that is unquestionably, legal.

From past experience the last several years, I dont want those headaches again as much as possible.

I'm with you on this one Glenn!

I think that the GDC has created rules this time, when all taken together, has the intention of driving design; rather than teams coming up with any and all designs and trying to fit/apply the rules to the design. With the stated bumper constraints - bumper segment size, perimeter coverage, trailer-bumper interaction, etc... there will a limited number of designs that meet those requirements!

836 is going conservative to mitigate risks of an un-approvable design. Long configuration - Front opening of 16" (6" of bumper segments on either side), appropriate opening for the trailer hitch and leaving it at that.

[banannaman20]

no actually that will get u a equipment damage penatly because u will end up beding the touge of the trailer and i agree that also doesnt pass the 6" rule