BUMPERS ARGHHH!!!!

[Bigflip2073]

Well I have been reading through CD post on bumpers and in the offical Q&A. and my question hasnt been answered.

Were planning to use brackets or angles to connect two bumper backings (as not to violate rule RO8) to make one single bumper that covers the corner. And yes both segments are at least 6". Legal?? yes no??? nes?

[Rick Wagner]

Originally Posted by Bigflip2073

Were planning to use brackets or angles to connect two bumper backings (as not to violate rule RO8) to make one single bumper that covers the corner. And yes both segments are at least 6". Legal?? yes no??? nes?

Yes, that's legal so long as you comply with <R08> L (BUMPERS must be fixed to the BUMPER PERIMETER), with <R08> M (The entire length of the BUMPER backing must be supported by the structure/frame), and with <R08> N ("Hard" parts of the BUMPER ... may extend up to ... one inch beyond the BUMPER PERIMETER).

[gorillamonky]

if i am understanding what you are saying, it sounds like you are going to connect the two plywood backings at the corner, so long as they do not extend beyond the metal that they are connected to and so long as they are 6" or more you should be ok

[Alan Anderson]

Originally Posted by <R08>O

The BUMPER backing must not extend beyond the “edge” of the ROBOT. The backing of adjacent BUMPER segments must not attach to each other if the attachment would require that the joint extend into the corner (see Figure 8 – 4).

If the joint doesn't "extend into the corner", you won't be violating this rule.

[GaryVoshol]

Originally Posted by <R08>

O. The BUMPER backing must not extend beyond the “edge” of the ROBOT. The backing of adjacent BUMPER segments must not attach to each other if the attachment would require that the joint extend into the corner (see Figure 8 – 4).

Note the second sentence - it sounds like that is what you are trying to do. Don't do it.

[chinckley]

I am so confused on these bumpers. The rules seem much more nebulus than in years prior. Is there an upper limit as to how high the bumper can be placed? Bottom limit? In the past they could be between the 2 and 8 inch mark from the ground. Someone mentioned they thought it was the 7inch limit for top. Can anyone confirm?

Also, I am not understanding Figure 8-4. I do not understand the okay versus not okay drawing. If the backing is within the 38" limit what is the problem?

I have read and read and read all the chief Delphi posts and the Q&A posts and am really confused. Is there one thread that really explains all this. I have been working on bumpers all the years we have had them and this is the first year of confusion.

Thanks for your patience.


Carolyn

[Russ Beavis]

Rule R08-P + check the definition of BUMPER ZONE.

Figure 8-4 is "Not OK" since the bumper backing is extending into the corner (a violation of rule R08-O).

Russ

[Alan Anderson]

Originally Posted by chinckley

I am so confused on these bumpers. The rules seem much more nebulus than in years prior. Is there an upper limit as to how high the bumper can be placed? Bottom limit? In the past they could be between the 2 and 8 inch mark from the ground. Someone mentioned they thought it was the 7inch limit for top. Can anyone confirm?

The Game Manual confirms that the BUMPER ZONE is the region between one and seven inches above the floor. <R08>P confirms that the BUMPERS must be designed to remain within the BUMPER ZONE.

[chinckley]

Originally Posted by Alan Anderson

The Game Manual confirms that the BUMPER ZONE is the region between one and seven inches above the floor. <R08>P confirms that the BUMPERS must be designed to remain within the BUMPER ZONE.

We are okay for Update #2 Section 8. We meet all these "rules" but what are the pictures on the top of the next page attempting to show? If our opening is less than 26" are we fine?

[EricH]

Originally Posted by chinckley

We are okay for Update #2 Section 8. We meet all these "rules" but what are the pictures on the top of the next page attempting to show? If our opening is less than 26" are we fine?

The pictures are not meant to be rules. If your opening is less than 26", you will almost certainly be fine as long as the bumpers cover the remaining foot with 6" on each side. (On a "wide" robot, it's 26"; a "narrow" robot has 16"due to the rules/the interpretation of protected.)

However, the pictures are not intended to show anything other than examples of legality with regards to one specific part of the rule.

[MrForbes]

Originally Posted by chinckley

Is there one thread that really explains all this.

No that I know of. You're on your own. Good luck.

[dlavery]

Originally Posted by chinckley

I am so confused on these bumpers. The rules seem much more nebulus than in years prior. Is there an upper limit as to how high the bumper can be placed? Bottom limit? In the past they could be between the 2 and 8 inch mark from the ground. Someone mentioned they thought it was the 7inch limit for top. Can anyone confirm?

Also, I am not understanding Figure 8-4. I do not understand the okay versus not okay drawing. If the backing is within the 38" limit what is the problem?

I have read and read and read all the chief Delphi posts and the Q&A posts and am really confused. Is there one thread that really explains all this. I have been working on bumpers all the years we have had them and this is the first year of confusion.

Thanks for your patience.


Carolyn

Carolyn (et al) -

If there is still serious confusion about interpretations of the bumper rules, and how to apply the rules to your robot, please post specific, detailed questions to the FIRST Q& forums.

Chief Delphi forums are wonderful resources full of great technical information, team organization ideas, event details, strategy discussions, and related/unrelated topics too numerous to recount. But one thing that you can not find here is a binding determination of what a rule means or how it will be interpreted by the inspectors or referees at a competition. For those questions, you need to resort to the official FIRST Q&A forums.

The different answers you have received in this thread offer an excellent example of why you should refer to the official Q&A system for these sorts of questions. Some of the answers here, as well-intentioned as they may be (particularly by a few self-appointed rules experts that seem to post in every single thread), are just plain wrong. The inspectors follow the official guidelines delivered from FIRST, which are based solely on The Manual, the Team Updates, and the FIRST Q&A forums. Any rules interpretations you may get here will not carry any weight with the robot inspectors once you get to a competition.

When posting to the FIRST Q&A, try to make your question as specific and detailed as possible. The Q&A can't be used for a design review, but can be used to ask for clarification and understanding of what a rule means and how it will be applied. For example, it would not be appropriate to submit drawings of your robot and ask "is our robot legal?" But asking "does Rule <R09-P> mean that the entirety of the bumpers must be contained within the Bumper Zone, and therefore be between one and seven inches above the floor?" would be a great question that would result in an equally specific answer.

-dave


.

[chinckley]

Originally Posted by dlavery

Carolyn (et al) -



When posting to the FIRST Q&A, try to make your question as specific and detailed as possible. The Q&A can't be used for a design review, but can be used to ask for clarification and understanding of what a rule means and how it will be applied. For example, it would not be appropriate to submit drawings of your robot and ask "is our robot legal?" But asking "does Rule <R09-P> mean that the entirety of the bumpers must be contained within the Bumper Zone, and therefore be between one and seven inches above the floor?" would be a great question that would result in an equally specific answer.

-dave


.

Thanks Dave. Would you think the Conference call on 2/5 would be good for official answers concerning bumpers too. My understanding is that they are going to go over how bumpers are going to be inspected.

[BenB]

Originally Posted by Bigflip2073

Well I have been reading through CD post on bumpers and in the offical Q&A. and my question hasnt been answered.

Were planning to use brackets or angles to connect two bumper backings (as not to violate rule RO8) to make one single bumper that covers the corner. And yes both segments are at least 6". Legal?? yes no??? nes?

It sounds like you are thinking about doing something like this

http://www.chiefdelphi.com/forums/at...2&d=1233599363

If that is the case, I got this response from the Q&A about it

Originally Posted by GDC Q&A

The "soft" parts of the BUMPER assembly (the pool noodles and fabric covering) can extend around corners and be continuous assemblies. The BUMPER backing must not extend into the corner spaces. So, adjacent segments of BUMPERS can be attached to each other through their "soft" elements, but through those elements only.

My interpretation of this is NO, you may not use a brace if you intend to permanently attach it to the bumper assembly. I came up with a solution to make a brace using "soft" parts of the bumper only. I can model it and post a picture here if you would like.

[jgraber]

Originally Posted by 2166BlueBotics

It sounds like you are thinking about doing something like this

http://www.chiefdelphi.com/forums/at...2&d=1233599363

If that is the case, I got this response from the Q&A about it

My interpretation of this is NO, you may not use a brace if you intend to permanently attach it to the bumper assembly. I came up with a solution to make a brace using "soft" parts of the bumper only. I can model it and post a picture here if you would like.

My meaningless vote is with BigFlip. I have a pending Q about it, something like this: is there a limit to how far inside the robot perimeter the bumper part of a bumper bracket may extend? Is there a limit to the number of bumper segments that may attach to one bracket?
Until overruled by tonight's conf call, or the Q&A, I intend to have two solid horizontal left side plywood braces whose edges are coincident with the robot perimeter but extend inward above/below the frame, and permanently attach the bumper segments to it. This will stiffen the frame as well. Attached with bottom bolts through the bottom/frame/tee-nuts in top brace.

Bumper weight: my prototype 48" x 5" x 3/4" oak plywood weighs about 3 lbs. With two full length noodles and fabric, about 4.5 lbs. This represents the weight of all left side bumper segments, so I have 4.5 lbs of margin to add braces, staples/glue to hold fabric, bolts, t-nuts, screws, etc, per side,
to add up to 18lbs.
I imagine I'll have to leave an inspection flap at the corners to show the inspector that the bumper segments meet point to point at the corner without intruding into the corner. Since this is stock frame, I'll have to have pockets drilled in the bumper backing for the axle bolts, which makes the robot perimeter a little fuzzy.

18lbs of bumpers seems like a lot compared to some fancy milled aluminum 3 lbs frames I read about here...

The top edge of the bumper needs much more bracing than the bottom,
given the bumper zone is not centered on the stock frame.