Circular/cornerless robot - Bumper free or fully bumpered?

[Leav]

When reading <R22>, I immediately thought "what if the robot doesn't have corners?" (e.g. a circular robot)

I could interpret it both ways:

Bumpers must cover corners. no corners, no bumpers.
An pentagon would has five corners, a hexagon six corners, an octagon eight, a nonagon nine, a decagon ten.... a circle is ALL CORNERS, and thus must have full bumper coverage.


Unless I missed something, it's definitely one for the Q&A...

-Leav

[Jon Stratis]

I would say... A circle is an infinite collection of corners, and as such not allowed, as you can't have 8" of bumper on either side of each and every corner!

[Leav]

I would say... A circle is an infinite collection of corners, and as such not allowed, as you can't have 8" of bumper on either side of each and every corner!

Interesting! I'd challenge that by saying that if the robot was fully encircled with bumpers it would indeed have 8" of bumpers on either side...

[brndn]

Regardless of the technical definitions of circles and corners... I think FIRST would like bumpers on every robot :)

[Richard Wallace]

I think Brandon's right.^

So, assuming it must have bumpers, would a circular frame with <112 inch perimeter (i.e., <35.6" diameter) offer any advantage for Ultimate Ascent?

[Leav]

I think Brandon's right.^

So, assuming it must have bumpers, would a circular frame with <112 inch perimeter (i.e., <35.6" diameter) offer any advantage for Ultimate Ascent?

Harder to pin down or stop?

[Al Skierkiewicz]

I think that Jon is on the right track. With an infinite number of exterior corners, and a bumper that completely surrounds the circular robot, it would be impossible for an inspector to state the the rule is not satisfied. An inspector would not be able to determine where one starts and the other ends. Backing into the description, if the bumper surrounds the robot it must be completely protecting the frame perimeter regardless of corners.

[topgun]

I think that Jon is on the right track. With an infinite number of exterior corners, and a bumper that completely surrounds the circular robot, it would be impossible for an inspector to state the the rule is not satisfied. An inspector would not be able to determine where one starts and the other ends. Backing into the description, if the bumper surrounds the robot it must be completely protecting the frame perimeter regardless of corners.

I am a little confused. So you are saying a completely round robot surrounded completely with a bumper would satisfy the rules? What about the numbering? I suppose just put at 90 degrees and call it good.

The other question is how to make a completely round bumper out of 3/4" wood material.

[GaryVoshol]

The other question is how to make a completely round bumper out of 3/4" wood material.
Steam box.

Going back to a non-circular robot, if one of your edges between corners is less than 8", you're out of luck. You can't protect 8" on either side of a corner of the adjacent edge is < 8".

[Richard Wallace]

Going back to a non-circular robot, if one of your edges between corners is less than 8", you're out of luck. You can't protect 8" on either side of a corner of the adjacent edge is < 8".Building on that -- since the perimeter cannot exceed 112", a polygonal frame perimeter cannot have more that 112/8 = 14 sides. So a frame perimeter with, say, one million sides would be illegal -- and indistinguishable from a circle. Hmm, maybe the circular frame perimeter is illegal after all?
:rolleyes: ::rtm:: :confused:

[JJackson]

The other question is how to make a completely round bumper out of 3/4" wood material.

You could laminate your own plywood into a circle. You would also have to make a jig to hold it as the glue dries

[FrankJ]

You could steam the plywood & make a circle.

But R2 describes the frame as a polygon. It is stretching the definition of a circle to call it a polygon.

R22 requires 8" of bumper between each outside corner of a polygon. Even if you buy into a circle being a polygon, there is not 8' between outside corners.

R29A Requires the bumpers be supported by the frame 1" from each end the bumper. How can you do this if the bumpers have no end?

Not being a inspector or on the rules committee, my opinion is not the one you have to use. :]

Anybody notice that R22 exempts the bumpers from bag & Tag?

[Al Skierkiewicz]

Isn't anyone going to talk about the need to have a continuous backing board to prevent someone from determining a start and end to the bumper? Or getting the bumper to weigh less than 20 lbs? Boy you guys try to make my job harder every year.

[DonRotolo]

I think Brandon's right.^

So, assuming it must have bumpers, would a circular frame with <112 inch perimeter (i.e., <35.6" diameter) offer any advantage for Ultimate Ascent?You could roll it sideways instead of using a robot cart?
I am a little confused. So you are saying a completely round robot surrounded completely with a bumper would satisfy the rules? What about the numbering? I suppose just put at 90 degrees and call it good.

The other question is how to make a completely round bumper out of 3/4" wood material.I think a circular bumper would pass inspection. I would pass it, as an inspector. Al S (THE Lead Robot Inspector) says so too.

To make such a bumper, make your own plywood. 1/16" strips of wood, steamed, glued and clamped will make a plywood circle. Ever see a bent-wood chair?

Leav, if you build that please post a photo! That would look awesome!

[AdamHeard]

With access to a moderate sized wood router, teams could also cut hoops then stack and glue them vertically.

[Leav]

You could roll it sideways instead of using a robot cart?
Nice!



Leav, if you build that please post a photo! That would look awesome!
Oh... I think i'll be focusing on actually throwing discs and climbing the pyramid... no time to muck about with a circular robot! :)

[nathannfm]

What's everyone think about an oval or football/lemon shaped frame perimeter, with pointy ends, the points are clearly "outside corners" so we would need bumpers on them, but what about the rest, of it?...or any convex frame...has this never come up before?

[DampRobot]

I really like how this thread has turned into a serious discussion of the benefits of circular robots, and features some of the best CD members. Let's take this discussion one step farther: what about a spherical robot?

As a robot inspector, I would read the rules as such. The frame perimeter is defined as a polygon. A polygon has corners. So the corners would have to be covered (to 8") with bumpers. So the robot would need to be encompassed by bumpers.

[nathan_hui]

Not necessarily. The frame perimeter in the contact zone needs to be covered in bumpers. The rules never specify bumpers above the contact zone. In fact, the robot cannot exceed the frame perimeter (at the contact zone, thus the bumper perimeter) in starting configuration, so a spherical robot is impossible.

A circular robot on the other hand would be confounding. However, let's assume for a moment that the robot is perfectly circular (practically, it never could be). Thus, there would exist either no corners, or an infinite number of corners. Now, a strict interpretation of the rules indicates that each corner must have at least 8" of bumper on either side not that each side be at least 8 inches. Thus, if a circle were to consist of all corners, then the entire frame perimeter would need to be covered with bumpers. If it were not, then no bumpers!

However, we know we can't make a perfect circle. We'll have to make it an infinitesimal n-gon, or as near that as possible. Thus, we define it to be infinite corners, thus the robot needs bumpers on all sides. Practically, though, it'd probably be a single U-channel bent and welded or bolted at one spot to itself to close the circle. So if you could bend it nicely, then it'd actually be a teardrop, so you'd only need a 16" bumper near the weld!

To be honest, the rules, especially in previous years, have had disclaimers stating that the intent of the rule, not the word of the rule, will be enforced. I believe the intent of the rule here is to prevent injury and damage to a robot or human should a corner come in contact with something. A 90 degree corner will normally rip stuff, if there's no covering on it. A round bot won't run corners into anything, it'll just rub. I don't think bumpers were intended to protect much against head-on collisions - it wouldn't help with holes in the bumpers (as the rules currently allow), so I think that the inspectors wouldn't consider that. Likewise, the GDC probably wouldn't have thought this discussion possible, or if they did, they probably (and rightly so) guessed it to be purely theoretical.

Sorry about the rant. I think I got my point through though.

[JosephC]

Every year we're told to not lawyer the rules. In every previous FRC year, to my knowledge, circular have A. been legal and B. completely surrounded by bumpers.

Lets not over complicate things ;)

[Tristan Lall]

Every year we're told to not lawyer the rules. In every previous FRC year, to my knowledge, circular have A. been legal and B. completely surrounded by bumpers.

Lets not over complicate things ;)
Since you raised the spectre of previous years, I thought I'd dig up this old thread (http://www.chiefdelphi.com/forums/showthread.php?p=811295#post811295). We've had issues with corners and corner protection before.1 I think I could justifiably attribute some measure of post-traumatic stress to the bumper definition problems of 2009 in particular, so for the sake of everyone involved, I hope FIRST has learned from the past and satisfactorily clears everything up in the very first update.

(On balance, the 2013 bumper rules are much improved. FIRST has eliminated points of confusion and overspecification, improved the documentation and clearly taken many suggestions to heart.)

1 Edit: That's the collective "we"—meaning the FRC community in general—not a reference to any particular team.

[NanoCollins]

Didn't a team make a circular robot a few years ago... for like Lunacy or something? :confused:

[Dragonking]

make a circular robot with a square bumper surrounding it