Re: Team Update #2
 

In previous years this would not fly. You couldn't have additional hardware of any type on the back side of the board, except for the fastener that came through the board. But you know the caveat about last year's rules.

And I just found it:
(emphasis mine)

Re: Team Update #2
 

I think they did say it, Paul. Taken together, the language quoted below and the section view shown in Fig. 8-1 seem pretty clear to me. A cross section taken anywhere through the bumper segment must include all of the elements shown in the figure, and the minimum segment length is 6 inches.

Re: Team Update #2
 

Richard,

So the part of the BUMPER that is beveled and sticking out of the BUMPER PERIMETER is nto a BUMPER? If not, then does it count for robot weight or BUMPER WEIGHT?

Your argument (and the GDC too, BTW) is like saying a plane must have wings, but the cross section of the plane that doesn't have wings is not part of the plane ... c'mon if that is not splitting hairs, then I don't know what is.

Paul

Re: Team Update #2
 

Subsection J of <R08> says that bumpers MAY have additional bits of noodles extending to protect the corner. It doesn't say MUST. So there must be other ways of doing it to comply with subsection I - but what are they?

Re: Team Update #2
 

I interpret the term "cross section" (as used in the rule) to mean a section taken by a plane perpendicular to the BUMPER PERIMETER. In the corner regions, "cross section" is not uniquely defined, because the BUMPER PERIMETER has a singularity (cusp) at each corner. So Fig. 8-1 cannot be applied to corners, and therefore special rules for corner protection are needed. These are provided by <R08-J>.

[edit]I agree with Gary; the word MAY in <R08-I> should be replaced by the word MUST or SHALL.[/edit]

Re: Team Update #2
 

Just to add to this thread:

There is a Q&A post here that clarifies the minimum length discussion.

Re: Team Update #2
 

My head hurts. Ok, so in the drawing of this update,the footprint of the robot could not get any bigger? What i am trying to ask is as you build upwards, you could not build over the indentation because you would break your bumper perimeter?

Re: Team Update #2
 

The definition of Bumper Perimeter is defined as taking string along the outermost vertices of the robot. Once your bumper perimeter is defined in that manner, you may not go outside of it with any part of your robot. An indentation in the robot (even if bumpers are built on it) does not count as the bumper perimeter and may be built over. Bumpers not placed on the bumper perimeter (the indentation) are superfluous and not required by rules.

Re: Team Update #2
 

I submitted a post to the Q/A that I believe covers most if not all of our questions: I've copied it as follows. I hope they reply with more than "Please Refer to Team Update #2".

Rule <R08-A> states that "BUMPERS must be built in segments, with a minimum length of six inches, and a maximum length that does not exceed the maximum horizontal dimension of the ROBOT."

1. What defines a bumper "segment?"
2. From where is the length of a bumper "segment" measured?
3. Is the bumper that wraps around the left rear corner of the robot in Overhead View Figure 8-2 in the Robot Manual considered a single bumper "segment"?
4. May a 6-inch-long bumper "segment" wrap around a corner, in any proportion, such that for example 2 inches of the 6-inch segment may exist on one side of the robot, and 4 inches exist on the adjacent perpendicular side of the robot. Is this still considered a single "segment" for the purposes of satisfying <R08-A>?

Rule <R08-I> states "BUMPERS must protect all exterior corners of the BUMPER PERIMETER".

1. What defines a "corner?"
2. At what radius is a "corner" no longer considered a "corner"?
3. From which direction of contact must corners be protected?

Re: Team Update #2
 

This part of the rule could definitely have been written better and clarified better (in the update and the Q&A posts).

To me, it looks like FIRST has offered an interpretation of the bumper length specification that is more restrictive than in past years. Given the similarities in phrasing (compared to 2008), and the lack of an explicit statement describing this, I doubt that it was intentional.

In 2008, the rules required that "each STANDARD BUMPER segment must be a minimum of 6 inches in length". There was no guidance as to what "segment" meant, and I suspect that most inspectors used the simple, obvious rationale that a segment was a piece of bumper that could be removed from the robot on its own. That also meant that the length (measured in some reasonable fashion) would be at least 6 in.

For the 2009 season, FIRST says that "BUMPERS must be built in segments, with a minimum length of six inches", but also says that "[c]orners and joints between BUMPER segments may be filled...by wrapping the pool noodles around the corners". By speaking about joints between segments, and wrapping the pool noodle around that joint, it's apparent that FIRST is interpreting a segment to mean the piece of plywood, not the entire piece of bumper. Also, by saying "minimum length", it's unclear whether they mean for the length of bumper segments to be measured at the smallest dimension (i.e. the minimum length, which is probably along the perimeter), or if they're just rephrasing the old rule, which seemed to allow the measurement of length to be made across any reasonable dimension (presumably the largest dimension, to give the benefit of the doubt to the teams). Given the specific permission to use bevelled bumpers, this could have significant consequences.

In fact, you could argue that the meaning of "BUMPERS must be built in segments, with a minimum length of six inches" is to specify that each bumper must be composed of segments—maybe one or more, maybe more than one—and to also make a separate requirement that the entire bumper must have a "minimum length of six inches". That definition seems less likely, given the rest of the rule and past usage, but I don't think that there's anything that makes it strictly incorrect, or outright implausible. While I don't favour this alternative interpretation, I don't think I could really fault anyone for coming to it.

Unfortunately, I can't figure out a way to rationalize the GDC's response to FRC1114's question, with my preferred interpretation—it does work with the alternative interpretation, however. All of the other statements by FIRST (the rule, the update, the response to FRC1458) seem to be consistent (only) with the first interpretation, but by saying that "[t]he length of the the bumper assembly that includes ['a solid plywood backing (as well as the pool noodles and fabric cover)'] is what determines the "bumper length", FIRST seems to be favouring the overall dimensions (maybe even with segments taken together), rather than the minimum dimensions (with segments taken separately).

Ultimately, I'm wondering the same thing as Paul: if it's important, why not be precise? And if it's not important, just state that inspectors may use broad discretion in permitting bumpers that are not strictly compliant, but which are likely to function adequately.

Although I'm definitely grateful for some of the improvements that were made in the bumper specifications since last year, it looks like there are still some kinks to be worked out in this year's rule.

Re: Team Update #2
 

First, it seems clear to *me* that Team Update 2 is wrong - the rules as they stand now would allow for (probably) a 34 inch opening*. Hopefully we'll see more clarification on this issue from FIRST, but let's assume that you use "wraparound" bumpers to cover your front corners, which would come 2'' onto your front side. In theory you could design them to be less than that, but 2'' seems like a pretty practical limit. The problem as I see it is the chassis - how are you going to design a solid, robust chassis in significantly under 6''? And remember, no adamantium.

Second, to those unhappy with this rule - I understand your frustration. Coming up with a great design and then seeing it foiled by a rule change is a frustrating experience. However, try to keep in mind the intent of the bumper rules in general. The intent is to minimize damage to field elements and robots so that we can continue playing the game. If the bumper rules were lax enough that they didn't restrict overall robot design at least a little, it's hard to imagine that they would provide adequate protection. Also, keep in mind that everyone is in the same position here - so it's restricting your design, but it's also restricting everyone's, so at the end of the day it's just making you think more, and a wash in terms of the game.

Third, a friendly suggestion, particularly to new teams: FIRST changes the rules around pretty much when they feel like it and how they feel like it. Sometimes rule changes that (from my perspective) were obvious necesities from the beginning were not implemented until week 6 of build, or were never implemented. So, the suggestion is: design your bumpers (and your robot in general) so that you're not even close to violating these rules. That way, if they change the rules a bit, you won't be scrambling around Monday night in a panic.

Good luck to everyone, and hope things are going well after one week
Paul

Re: Team Update #2
 

I personally could not find this in the rule book and maybe I'm missing it but is there a height restriction on the bumpers?

Thanks for any of the help you can provide!

Re: Team Update #2
 

Charles,

Definitions:

BUMPER ZONE – the volume contained between two virtual horizontal planes, one inch above the
floor and seven inches above the floor.

R08:

P. BUMPERS must be mounted to the ROBOT within the BUMPER ZONE, and must remain
there. The BUMPERS must not be articulated or designed to move outside of the BUMPER
ZONE.

Wilmo

(we are all tired :P )

Re: Team Update #2
 

Just some clarification needed. Each side of the robot has to have bumpers on it, right?

Re: Team Update #2
 

Yeah, we think so, but maybe not....hopefully we'll get some substantial clarification.

Better plan on putting bumpers on every side, 6" minimum length at each end at least.