Circular/cornerless robot - Bumper free or fully bumpered?

[Leav]

Originally Posted by DonRotolo

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

Nice!

Originally Posted by DonRotolo

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]

Originally Posted by 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

Since you raised the spectre of previous years, I thought I'd dig up this old thread. 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?

[Dragonking]

make a circular robot with a square bumper surrounding it