FRC 2012: Update #3
 

The third team update is now available online. Team Update #3

Re: FRC 2012: Update #3
 

"each end of the Bumper must be rigidly attached to the Frame Perimeter" (emphasis mine)

What's that supposed to mean?


Does that mean bumpers like this are illegal?

[----<attachment>---------------<attachment>----]


And that these are legal?

[<attachment>-----------------------<attachment>]

Re: FRC 2012: Update #3
 

That seems to be true according to the rules.

Re: FRC 2012: Update #3
 

This would seem to make pulling off a WCD bumper mount much more of a pain. Why the GDC cwon't leave designing structurally sound bumpers up to the teams is such a great question.

Re: FRC 2012: Update #3
 

It seems they are trying to avoid allowing bumpers that attached only at the corner and/or leaving unsupported ends, although specific requirements need to be set out to leave out any ambiguity.

Re: FRC 2012: Update #3
 

Also of note is an update to the administrative section of the manual:

The bolded part is what's highlighted in the update, AKA the added part.

Re: FRC 2012: Update #3
 

Also, this makes the double C-shaped style of bumpers illegal too, no?

For those unfamiliar, they look like this: [ ] (Top view of robot) and usually the short lengths of the C are only attached to the frame at one point. The other side is supported by the edge of the long bumper.

This is very disappointing.

Re: FRC 2012: Update #3
 

I was a little confused as well.
Isnt the end of one side of a bumper unsupported when extended out to the depth of the other adjacent side?
I guess I know what they mean, ......its just the wording.

Re: FRC 2012: Update #3
 

Perhaps ambiguity should be able to be left. If the rule says, don't let your bumpers fall off, it's kinda common sense to build bumpers that won't fall off. Right? We inspire and recognize science and technology, but sometimes, common sense seems to be forgotten.......

Re: FRC 2012: Update #3
 

While what you are saying is absolutely true, I've been in enough regionals (20+), where not following the letter of the law, can prevent you from passing inspection.
Without diagram 4-3, it would have been quite ambiguious.

Re: FRC 2012: Update #3
 

Remember, it is the wood backing that must be supported and attached as specified. This update doesn't affect the unsupported extensions of pool noodle/fabric that you are referring to.

Re: FRC 2012: Update #3
 

The question then becomes: how close to the end of the bumper is the end of the bumper?

This is slightly annoying... :ahh:

Re: FRC 2012: Update #3
 

:ahh:

Re: FRC 2012: Update #3
 

It seems to me that they mean simply that the ends of the bumper must be supported by the frame (an exception to the general rule of 8" unsupported sections). How can anyone determine whether or not a fastener holding a bumper on is "at the end" or not? Where is the line drawn? 1 inch, 2 inches? And, structurally, why would it matter, assuming the end of the bumper is supported? However they do not say supported, they say attached, so we'll have to wait for clarification.

Perhaps they mean if you do have an unsupported 8" segment, the last supported segment on each end must be attached somewhere (and there must be no unsupported segment beyond it).

Re: FRC 2012: Update #3
 

That would be better than it is now. Ambiguity isn't bad as long as it doesn't mean a set of bumpers could fail inspection based upon nothing more than semantics (is the end of the bumper the terminal edge? is it the last 3in of bumper? etc.) or that a superior set of bumpers (vs. a set that passes) fails just because its supports are a 1/2in from the end.

That would be the most logical requirement to me, I hope, although somewhat doubt, that's what they mean.

Re: FRC 2012: Update #3
 

I regret asking for a simple game manual when it causes this much confusion.

The fact that the GDC didn't include how long the "end of the bumper" is means they probably didn't think about everyone requesting a specific measurable distance. Your robot bumpers need two attachment methods on the left and right side of the wood surface. One single attachment is not going to cut it and you need to spread them out as to get the most support possible.

Re: FRC 2012: Update #3
 

Agreed.

Re: FRC 2012: Update #3
 

This rule about fastening the bumpers was the result of the LRI training. It was noticed that a bumper and backing could extend 7 " into open air and still be legal. The rule as stated means that both sides of the gap must be fastened and no bumper backing can hang free over the gap. I hope that this clears things up.

Re: FRC 2012: Update #3
 

I'm still a bit confused on this. Does this mean that the bumpers need the 2 connecting brackets to be on the very farthest ends of it, or will it be ok as long as the bumper connectors are near the ends of the base, but not exactly at them?

Thanks!

Re: FRC 2012: Update #3
 

There could not be a vaguer update. Looks like we have to put off the fabrication of our chassis until an update defining what the "end" of the bumpers are.

Re: FRC 2012: Update #3
 

More Vague is the expression i believe you were going for, but this is not the english teacher board, nor am I an english teacher ;)

We are using a Kitbot chassis (KISS, especially with a 2nd year team with not a whole lot of practice time), and we already determined that we will need to modify our bumper connection some. All this does is delay our timeline on that (honestly I wasn't going to attack it until our shooter is done, and we need to get it over the front bumper).

Re: FRC 2012: Update #3
 

I would assume the words are interchangeable since "vaguer" is indeed a word according to the Merriam-Webster Dictionary. But you do have a point, "more vague" sounds better.

Nevertheless, this update is VAGUE and is confusing people more than before it was released.... Something an update should NOT do.

Re: FRC 2012: Update #3
 

As long as you don't say "more vaguer" your good. I thought we wanted a concise and precise manual, not a "simple" and nebulous one.

Re: FRC 2012: Update #3
 

Steve (just asking for your interpretation, not an official ruling)-

Is the intention that the bumpers simply be backed their entire length?

The way I first read the rule update I had the corner shaped bumper in mind. So when I read each "end" I read that each side of the corner must be attached. Meaning- you could not attach an angled bumper to a robot just on one side. was this the intention of the update?

-Brando

Re: FRC 2012: Update #3
 

Before this update, it would be very easy to construct a bumper that would pass inspection, but break off completely during the match. Some examples:

You have an open-ended robot. Essentially, it's a big "C". Across the missing side, you have 2 8" bumper segments that are only supported by the corners (since you have have up to 8" of bumper unsupported). When those bumpers take a hit, they'll bend inwards and break off.

You actually have support material behind the entire length of your 8" bumper, but you only have it attached at the corner. Your bumper is at the maximum height (5-10"). Another robot has its bumpers rigidly attached as low as possible (2-7"). When the two robots collide, there's going to be significant upwards force on your bumper due to the height difference in bumpers (in fact, I've heard some talk from some very experienced individuals about the increased possibility of tipping because of this height difference). Now your bumper either swivels up and is sitting at a diagonal outside of the bumper zone, or it breaks off completely.


The point behind attaching both ends to the frame perimeter is to ensure that the bumpers are attached to the robot in a way that will keep them from breaking off or otherwise not working as intended. Yes, I agree with others here that the rule change probably could have been worded better in order to get a similar end affect... but none of us are on the GDC.


PS. When trying to "Save as PDF" on any of the sections, is anyone else getting similar errors to this: "TCPDF ERROR: [Image] Unable to get image: http://frc-manual.usfirst.org/upload/Section1.jpg" I've been seeing that ever since update 2... I've tried on Both Mac and Windows, using IE, Firefox, Chrome, and Safari. While I can still manage to get them to print off in a PDF format using other tools, it then doesn't include the links and navigational aids I want.

Re: FRC 2012: Update #3
 

In case you didn't see it yet, today's Bill's Blog says the save as pdf problem is a known issue and they're working on it.

Re: FRC 2012: Update #3
 

My interpretation is that the bumper backing must be fastened to the robot frame so that minimal (less than an inch) backing goes unsupported and fastened. For example, if you have a gap in your frame that is 20" wide and you robot is 28" wide then to meet the minimum bumper rule, the bumpers must be 8 inches from each of the vertices. That would mean that there would be 4" of each bumper unsupported by the frame. There was no rule to cover this so FIRST says that the bumpers must be supported on each end.

I hope that this was of help but should be checked with Q&A and further team updates.

Re: FRC 2012: Update #3
 

This was covered in rule R28(B):

I think the intent is more along the lines of what Brandon said, to prevent teams from having loose end bumpers. Did any teams in the last couple of years, who built corner or "c" bumpers that weren't supported on all the sides, have them break at the wood joint? If so, this rule makes sense to prevent those bumpers from hanging just by the cloth if they break.

Re: FRC 2012: Update #3
 

That rule only applied to bumpers that were hanging off the end of the robot, not ones that were hanging in the middle of a gap in the frame. The general rule of thumb is "wrap a string around your robot within the bumper zone. That string is your frame perimeter." So any gaps in your frame do not change what the frame perimeter is, and prior to this update you could have up to 8 inches of unsupported bumper that was on the frame perimeter hanging off the edge of a gap. Now you have to make sure the other side is supported as well.

Re: FRC 2012: Update #3
 

This is correct!

Re: FRC 2012: Update #3 (aka I Hate Bumpers)
 

We ran into this "bumpers must be attached at the ends" conundrum at the pre-ship on Saturday (I am thankful we found out Saturday and not Thursday at our first regional).

We use the AM Kitbot Chassis. Does anybody have any good ideas on how to attach at the bumpers at the ends given all the bolts that are already in the end just for holding the kitbot chassis together?

<rant>I had two students spend probably 5 hours each just working on attaching bumpers to the frame, only to find out about they must be attached at the end rule. I have hated bumpers from year 1 (we are a 4th year team). There is so much time, brainpower, money and rules wasted in putting on bumpers every year for something that should be incidental to the robot design. </rant>

Re: FRC 2012: Update #3 (aka I Hate Bumpers)
 

I hear you.
We are doing some quick modifications to our bracket mount as its not at the "end" of the bumper but about an inch off from the end.:mad:

Re: FRC 2012: Update #3 (aka I Hate Bumpers)
 

We have a modified kitbot frame, and in the end (on the end of the robot with the gap for the collector) of the frame, we put a piece of 1x1 box that slides into the c-channel, this holds it in without another fastener. I think that satisfies the update, they really do need to clarify, and now that stop-work day has passed, there will be many teams frantically fixing bumpers on the first day of competition.