Fasteners extending outside the FRAME PERIMETER

[EricH]

You could also try getting some balsa wood. That's pretty light--in fact, a lot of R/C airplanes are made from it.

[Rick TYler]

Originally Posted by artdutra04

For those which cannot change their fasteners to flat head bolts, here's the McMaster part number that I think will save a lot of teams this year: 8782K12

1" wide x 1/4" thick polypropylene strips (...) will add just over a pound.
(...) 1/4" x 1" strip of Lexan will add over 1.3 pounds.

6mm Okoume plywood in a 1" wide strip around the robot would add about .6 pounds. Double-layer corrugated cardboard might even be lighter than that.

[GaryVoshol]

Originally Posted by Joe Johnson

As to the rivets below the bumper zone, unless they were lined up with ones in the bumper zone then they would have always been illegal. Am I right on this?

Not precisely. Previously if you had a row of rivets along your FRAME PERIMETER, they would have extended the PERIMETER along that side. Any rivet above or below the BUMPER ZONE, but still within the horizontal limits of that row, would have been protected.

Originally Posted by EricH

You could also try getting some balsa wood. That's pretty light--in fact, a lot of R/C airplanes are made from it.

Originally Posted by Rick TYler

6mm Okoume plywood in a 1" wide strip around the robot would add about .6 pounds. Double-layer corrugated cardboard might even be lighter than that.

Can you say "Squish!" Both of these materials would negate the whole intent of the reason for exempting protrusions in the first place, which was to ensure that bumpers were firmly attached to a solid frame member. I don't see anything that would prohibit the use of the materials. It's just that by using them, you make the bumpers less stable, not more robust as was noted for the reason it was changed in Team Update 6.

Next question, how are inspectors going to measure this for compliance? The old see-what-touches-a-vertical-wall-first test doesn't work. How can an inspector tell that your lower frame is or isn't really 1/8" smaller than your frame in the BUMPER ZONE which defines the FRAME PERIMETER?

[Rob]

I am with the group that rates this change to the design rules as unacceptable when presented at this time in the build season.

I hope that there is a misinterpretation here and that whatt appeared to be a previously acceptable condition will prevail.

While we have the ability to extend the size of the bumper zone by 1/4" in each direction it will require the purchase of some new material as well as the cutting of new bumper wood. This is simply a shuffling of words that created a great deal of waste.

A ruling like this creates the appearnace that the author of this update does not understand what teams go through during the build season. I hope that sanity prevails over misunderstanding and we do not see any other game changing updates during the season.

Rob

[Mike Betts]

Originally Posted by GaryVoshol

...Next question, how are inspectors going to measure this for compliance? The old see-what-touches-a-vertical-wall-first test doesn't work. How can an inspector tell that your lower frame is or isn't really 1/8" smaller than your frame in the BUMPER ZONE which defines the FRAME PERIMETER?

I can not answer for other inspectors, but I always bring a 6 foot level with me... I have only had to use it a few times...

[Mike Betts]

Originally Posted by sanddrag

I still can't understand why teams don't just build their robots an inch smaller than the sizing box. All this debate over bolt heads sticking out is just silly....

I agree completely. I can see a rookie team being blind sided by this but I have no sympathy for a veteran team.

If you have designed your frame too close to "exactly" 28x38, then you have opened yourself up to problems regarding variations in dimensions and of "squareness" of the sizing box and you should be prepared for failure.

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!

JMHO,

Mike

[johnr]

I will admit that after the last couple of years that i read the rules with an eye towards,"What does the gdc want all the robots to look like this year?" For some reason a flat top upside down pyramid came to mind. Now i know why. I feel bad for the inspectors that are going to have to tell a team that their rivet heads are out of perimeter.

[martin417]

Originally Posted by Mike Betts

I agree completely. I can see a rookie team being blind sided by this but I have no sympathy for a veteran team.

If you have designed your frame too close to "exactly" 28x38, then you have opened yourself up to problems regarding variations in dimensions and of "squareness" of the sizing box and you should be prepared for failure.

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!

JMHO,

Mike

Please read the thread before posting! As has been repeated MANY times throughout this thread, this debate has nothing to do with violating the sizing box, A 12" square robot can still be iin violation of this rule. If you don't understand what I mean, read back through this thread and it will become clear.

[Joe Johnson]

Originally Posted by martin417

Please read the thread before posting! As has been repeated MANY times throughout this thread, this debate has nothing to do with violating the sizing box, A 12" square robot can still be iin violation of this rule. If you don't understand what I mean, read back through this thread and it will become clear.

I think he may be referring to those teams that say they cannot space their bumper out (and thereby extend the FRAME PERIMETER) without having the robot be outside the 38"X28" overall size limit.

Joe J.

[jgannon]

Originally Posted by Mike Betts

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!

C'mon, man... you can't possibly tell me that "common sense" would have dictated that a bolt head protruding from your frame 15" off the ground is legal, but a bolt head protruding by the same amount 4" off the ground is not.

Look around this thread for a minute. When you see a WFA winner saying his interpretation of the rule is correct with "absolute certainty", and he turns out to be wrong, something has gone terribly, terribly awry.

[MrForbes]

Originally Posted by GaryVoshol

Can you say "Squish!" Both of these materials would negate the whole intent of the reason for exempting protrusions in the first place, which was to ensure that bumpers were firmly attached to a solid frame member.

You can easily poke your finger into balsa wood or corrugated cardboard. But if you lay a piece of either on the floor, then place a piece of 3/4" plywood on it, and stand on it, what happens?

If there is sufficient surface area behind it for support, these soft materials will probably work very well as bumper shims, to bring the FRAME PERIMETER out past the fastener heads in the lower part of your robot.

[Rick TYler]

Originally Posted by Mike Betts

I can not answer for other inspectors, but I always bring a 6 foot level with me... I have only had to use it a few times...

Whacking team captains with a 6-foot level might be satisfying, but it probably violates some rule or another. Sorry.

[IndySam]

Originally Posted by Joe Johnson

Paul,
What part of rule <R16> did the GDC screw up?

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

They gave us some freedom to have screw heads under the bumper but we had no right to expect that this would extend outside this space. There was a question, it was answered relatively fast and while there is time to work around it if you have to.

I don't see how we can blame the GDC.

Joe J.

I'm with you Joe. I thought the rule was clear from the start.

I think it just shows how people can look at the same rules and have different conclusions. That's why the GDC's job is so hard.

[IndySam]

Originally Posted by jgannon

C'mon, man... you can't possibly tell me that "common sense" would have dictated that a bolt head protruding from your frame 15" off the ground is legal, but a bolt head protruding by the same amount 4" off the ground is not.

Look around this thread for a minute. When you see a WFA winner saying his interpretation of the rule is correct with "absolute certainty", and he turns out to be wrong, something has gone terribly, terribly awry.

I can tell you that because that's exactly what common sense told me. The bolt protruding rule was to allow to help with bumper attachment and support. How does a bolt protruding 4" of the ground hamper mounting bumpers? So why would it be allowed?

I have nothing but respect for PC and have learned much from him over the years. Just because he is a WFA doesn't make him always correct.

[Vikesrock]

Originally Posted by IndySam

I can tell you that because that's exactly what common sense told me. The bolt protruding rule was to allow to help with bumper attachment and support. How does a bolt protruding 4" of the ground hamper mounting bumpers? So why would it be allowed?

I have nothing but respect for PC and have learned much from him over the years. Just because he is a WFA doesn't make him always correct.

But he was. The rules were clear, whatever stuck out the farthest in the Bumper Zone defined the Frame Perimeter, whether that was an axle or a bolt or a a hot glued army man.

Update 6 changed that, which may have shrunk the Frame Perimeter for some teams. If these teams were designing to fit inside the projection of their old larger Frame Perimeter and now do not fit inside the new smaller Frame Perimeter then this rule has taken a legal design and made it illegal. In week 4 that just does not seem to be a fair thing to do.