15-01-2009 22:29

smurfgirl

Re: pic: Broken Bumper from 2007

Wow... I have never seen a bumper that damaged before. Ours have stayed in tact through some pretty bad collisions- I can't imagine what could have happened to your bot. I hope nothing like this ends up happening this season... but I can definitely see where it might.

15-01-2009 22:33

EricH

Re: pic: Broken Bumper from 2007

I think our robot was part of the reason for the damage. 294 was defending 330 pretty heavily that regional, for some reason.

16-01-2009 01:13

AdamHeard

Re: pic: Broken Bumper from 2007

For reference, the bumpers used 3/8"-1/2" plywood (depending on which bumper), we're only supported on the extreme ends, with no support anywhere near it.

They were also shoddily made/installed at the last minute.

And probably most importantly, they were in the hands of an extremely wreckless driver who really only used 0 and 255.

16-01-2009 01:27

eugenebrooks

Re: pic: Broken Bumper from 2007

The bumper construction rules clearly specify 3/4 inch plywood.


Eugene

16-01-2009 01:30

smurfgirl

Re: pic: Broken Bumper from 2007

Ok, I guess the attachment points is where the real difference was made, the hits in the middle made all those indentations and crumpled metal. It sounds like this year's new rules will prevent bumpers that look like that (I hope?)

16-01-2009 01:32

AdamHeard

Re: pic: Broken Bumper from 2007

Yup, they clearly do.

The bumpers that year were totally forgotten until the last minute, and I believe made at the thursday of the regional itself. We made them with what we had, and let the inspectors know.

Either way, it was 2007, settle down.

16-01-2009 01:42

dtengineering

Re: pic: Broken Bumper from 2007

I take it, however, that the bumpers worked, and the robot survived?

It looks like classic 3 (or four) point beam bending, however, so if these bumpers were made of 1/2" plywood, a 3/4" plywood bumper would have been over twice as resistant to bending/breaking... and if they were made our of just 3/8", then the regulation bumper would have been four times as stiff.

Even then, had these been supported in the middle, they would have likely survived fine... but I guess that is the point, isn't it? Build them like the rule book says and you won't have a problem!

From another perspective, it was quite disappointing for me as a tech inspector in Atlanta last year to have to fail teams on tech for not having followed the bumper rules. (Of course the inspection team helped them source FRC legal bumper materials, or devise suitable repairs, but it wasn't a particularly productive way for teams to spend their time.) It wasn't that I wanted to do it... but the job of the inspector is to enforce the rules, not to bend them, modify them, or make them up on the spot.

Jason

16-01-2009 02:02

eugenebrooks

Re: pic: Broken Bumper from 2007

The bumper construction rules are very specific, and bumpers are required, for a reason. The specifications lead to a bumper that will withstand the rigors of the competition.

It is a shame for an inspector to have to fail a robot for something like failing to construct and mount the bumpers properly, but if bumpers are not present and mounted properly according to the rules the robot should not be allowed to compete. This is not a small thing in the rules that can be ignored.

I hope that past damage to improperly made bumpers did not cause the rules adjustment requiring structural support for the entire length of the bumper this year. Many teams like to build cantilever wheel systems and I see no reason why they should not be allowed to do it if the bumper mounting is sound.

Flimsy structural support behind the bumper satisfies the letter of the rule, but not the intent. I think that making post mounting of the bumpers illegal is silly, in that it can be done with high strength. It does not affect us as we stopped building cantilever wheel systems a few years ago, but it certainly affects quite a few other teams.

I don't consider myself to be in a state that requires settling down...

Eugene

16-01-2009 10:33

RyanS

Re: pic: Broken Bumper from 2007

It was 3/4 in plywood. Just the fact that the attachment points were really far apart and it was cheap plywood was the problem.

16-01-2009 11:41

Taylor

Re: pic: Broken Bumper from 2007

Even though you didn't particularly enjoy it, I applaud you for doing your job. This reminds me of the classic 'contract rider' example with performing artists. Often, the artists would include rather obtuse demands in their contract - the most famous would be Van Halen requiring the promoter to provide them with M&Ms with all the brown ones taken out. They knew if the promoter did this, then he read the whole contract and their other requirements were met.
This year I feel the GDC has taken us by the hand and said "this is EXACTLY how we want you to build the bumpers." If a team can't do that, then I would be very concerned how they handled important things like nuts & bolts & wiring.

16-01-2009 11:41

Taylor

Re: pic: Broken Bumper from 2007

..

18-01-2009 16:44

amariealbrecht

Re: pic: Broken Bumper from 2007

wow i dont think our bumpers have ever looked liked that but i could imagine how with this years game they sure could end up looking like!
Best of luck this year,
Alicia Albrecht
Electrical Subteam
The Robettes 2177

18-01-2009 16:54

IndySam

Re: pic: Broken Bumper from 2007

In 2007 we had a bumper supported only on the ends of it's 35" length and it was broken. It was replace by furniture grade plywood and that was broken. That was replaced again and aluminum angle was added and and it too was broken.

140lb robots can break almost anything.

18-01-2009 18:32

AdamHeard

Re: pic: Broken Bumper from 2007

And almost anything can withstand 151lb robots if properly attached/designed.