Re: Aluminum angle on bumpers
 

See this Q&A forum answer. No steel angles. No steel plates. No lead weights. No small rodents. No Chinese food from lunch. You have to make the bumpers out of the items that they have always said they must be made from - plywood, pool noodles, fabric covering, aluminum angles, and fastening system. Nothing else.

-dave


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Re: Aluminum angle on bumpers
 

I really don't mean to derail this thread, but I'd like to point out for future GDC consideration that this is an excellent demonstration of how defective the wording of bumper rules was this year. Calling the rules unclear is inaccurate; they are very clear... the only problem is that everyone seems to find them clear in a different way. If there are any two people on this planet who should accurately understand these rules, they are Dave Lavery, a guy who helped write the rules, and Russ Beavis, the guy in charge of telling inspectors how to enforce them. For there to be this substantial of a disagreement this late in the season is really troublesome.

I don't think there's any question that literally hundreds of teams are going to show up to competition with illegal bumper configurations this year. For many of them, it won't be because they didn't read the manual, but rather because they read it, applied a reasonable degree of logic, and still ended up with a different interpretation than the one intended. I'm afraid it's going to be a huge mess, I feel like it could have been avoided, and I'm very hopeful for vast improvements next year.

Re: Aluminum angle on bumpers
 

Since this opinion was on Chief Delphi, it is not necessarily correct or even accurate. Only those views expressed from the GDC (or FRCOPS) on the official Q&A are to be regarded as gospel. Quite frankly, I don't trust this "dlavery" fellow.

Re: Aluminum angle on bumpers
 

would it be considered illegal if steel brackets are used as part of the robust attachment system seeing as how there are no definitions on what a robust attachment system is?

Re: Aluminum angle on bumpers
 

ummmmm.....how about you ask on the Q&A? :)

My wild guess it that you could use steel brackets and large steel bolts as part of your robust fastening system. Last year we used 5/16" coupling nuts (they're over an inch long) as part of our nut-and-bolt fastening system, they're much easier to hold onto that normal nuts.

Re: Aluminum angle on bumpers
 

Well apparently the only robust attachment system allowed is a bolt with a tee put into the plywood as per figure 8-1. Even though parts G and H of R08 seems to imply there is a possibility of other robust fasteners. The note in the primary paragraph of R08 ("To achieve this, BUMPERS must be constructed as described below and illustrated in Figure 8 – 1") defeats the later subsections of the rule.

Re: Aluminum angle on bumpers
 

Which is why I suggested asking on the Q&A. According to fig 8-1, the aluminum angle is a required part of the bumpers, but the GDC said it's optional on the Q&A. If you want to find out, ASK ON THE Q&A.

Re: Aluminum angle on bumpers
 

That's a perfect example of two problems with the rules this year.

One: if the angle is optional, why don't the rules say so? (And why haven't the rules been updated, given that this question was first raised weeks ago?)

Two: if the Q&A advises something that isn't directly supported by the rules, what do teams do? (And what do you expect the inspectors to do? Assume that a Q&A is as good as a rule change, and make the teams comply with the Q&A?)

Re: Aluminum angle on bumpers
 

Somebody remind me to nominate Tristan to the GDC, if that's possible. If nothing else, he can check for clarity in the wording of the rules.

Re: Aluminum angle on bumpers
 

Print the question and answer, and have it with you at inspection time, just in case there's an issue.

Re: Aluminum angle on bumpers
 

The problem is with graphic communication. The GDC supplies graphics in the Robot Manual to help describe what they are specifically referring to in certain rules. However, the graphics may contradict other rules. Unfortunately, the graphics can lead readers to conclusions the GDC never intended. Then us mere mortals rely on the Q/A to clear the confusion.

I am assuming in Figure 8-1, you are supposed to infer that the use of aluminum angle is optional because no bumper rule expressly tells you to use aluminum angle.

In Figure 8-2 (I know, beaten to death), you are not supposed to infer anything and simply look at the "OK" corner configurations.
The GDC would say they provide clarification, meaning the Q/A responses are direclty supported by the rules. (that sentence may get me in trouble)

For me personally this has been a very tiresome year. The GDC wants a very specific bumper design. Unfortunately, the rules seem to be very non-specific and the graphics are confusing. Some folks around here find it simple and straight forward. They think that anyone who doesn't is either: A.) Trying to advance an illegal robot design, B.) lawyering the rules, C.) a moron; which have led to some viscous personal attacks. Quite frankly I don't pour my seemingly dwindling free time into something that I think is a waste of time. I think the rules discussions are important because it provides a platform for the GDC to understand where our thought process is- how people, who don't know the GDC's intent, interpret the rules.

Re: Aluminum angle on bumpers
 

Of course the tricky part is knowing just what you are supposed to infer

That's why we have the Q&A, I guess!

Re: Aluminum angle on bumpers
 

Do your best and the Inspection Team will help, if needed, get you the rest of the way. We have and will be discussing the bumpers on our phone conferences and your inspection team will be up to date on the GDC decisions at each event. With the 18 lb limit, construction should not be a problem. Bowing to the Great Karnack, I will predict that we will see teams with issues using weak fabric, something other than 3/4" plywood backing, hard parts in the corners, and less than rigid fastening systems. And I also predict we will see teams with sections less that 6" long, and no robot structure to back up the bumper.

Re: Aluminum angle on bumpers
 

To the more experienced teams out there - please consider bringing plenty of extra fabric, aluminum brackets, pool noodles, plywood and "robust fastener systems". Since these can all be unmodified COTS items, you can bring as much as you'd like.

Your robot inspectors and rookie teams (ie your potential alliance partners) will be VERY grateful. There will probably be a LOT of bumper re-building on Thursdays.

Russ

Re: Aluminum angle on bumpers
 

Unless you've pre-cut your COTS 4' x 8' sheet of plywood into bumper width strips...
Luckily, I don't believe we'll be anywhere close to our 40 lbs of fabricated parts and can donate some of our weight allowance to these spare bumper parts.