Are extensions with bumpers after the start of the game legal

[staplemonx]

We are looking to increase our surface area to make a better blocking robot after the autonomous period and before the end game. To do that we want to extend out to fill the 84 cylinder and block as much of the scoring lane as possible. If we include the bumper on the extensions as part of robot dimensions are we legal?

The tan objects represent the extensions in their starting positions. The colored objects represent the base and the extensions in their blocking configuration.

[Racer26]

An interesting strategy.

I am not going to say that it is legal, but there are no violations immediately jumping to mind.

[Tristan Lall]

Originally Posted by staplemonx

We are looking to increase our surface area to make a better blocking robot after the autonomous period and before the end game. To do that we want to extend out to fill the 84 cylinder and block as much of the scoring lane as possible. If we include the bumper on the extensions as part of robot dimensions are we legal?

The tan objects represent the extensions in their starting positions. The colored objects represent the base and the extensions in their blocking configuration.

The thing to remember is that the extensible things aren't bumpers in the conventional sense—mainly because they fail <R07> part B—even though they may look like bumpers. To that end, they need to satisfy all rules, one of which dictates that nothing may overhang the frame perimeter in starting configuration (<R14>).

And you can't declare it part of the frame perimeter, since the frame perimeter must be composed of non-articulated elements—you'd fail inspection on account of <R12>.

[jspatz1]

There is no rule that keeps an arm or other appendage from coming down into that area, so I see no reason why these frame extensions cannot. In fact they technically would not need to have bumpers on them, however that might be wise.

[staplemonx]

Originally Posted by Tristan Lall

The thing to remember is that the extensible things aren't bumpers in the conventional sense—mainly because they fail <R07> part B—even though they may look like bumpers. To that end, they need to satisfy all rules, one of which dictates that nothing may overhang the frame perimeter in starting configuration (<R14>).

And you can't declare it part of the frame perimeter, since the frame perimeter must be composed of non-articulated elements—you'd fail inspection on account of <R12>.

Makes sense. So if we reduce the width of the extensions so that the pseudo bumpers do not over hang the frame perimeter it looks like we are in business.

[JesseK]

This is a creative and interesting concept for defense, I think. At first glance I don't think it's illegal in its present form. Just keep in mind that the "bumpers" on the extensions must be included in the weight of the HOSTBOT, and cannot be thought of as the bumpers in the BUMPER specifications. Thus you can do pretty much whatever you want with them.

However, I think that this design is susceptible to easily being turned for two reasons:

1.) The extended frame creates more mechanical advantage for another robot to turn you.
2.) Even with traction wheels on the corners, there's very little weight on the outer corners in the extended positions; thus they provide little protection from another robot turning you.

If you're always beyond the Caution line and get turned into the opponent scoring zone by a high-traction high-torque robot, your robot will receive a penalty, per <G32>.

Thus, solve the anti-turning problem and I think that this is a solid strategy that blocks a good amount of the scoring zone.

[Eugene Fang]

Cool concept, but I worry about legality.

"BUMPER ZONE – the volume contained between two virtual horizontal planes, one inch above the
floor and seven inches above the floor"

In your starting configuration, the bumpers do not start in the "Bumper Zone."

[staplemonx]

Originally Posted by JesseK

I think that this design is susceptible to easily being turned for two reasons:

1.) The extended frame creates more mechanical advantage for another robot to turn you.
2.) Even with traction wheels on the corners, there's very little weight on the outer corners in the extended positions; thus they provide little protection from another robot turning you.

If you're always beyond the Caution line and get turned into the opponent scoring zone by a high-traction high-torque robot, your robot will receive a penalty, per <G32>.

Thus, solve the anti-turning problem and I think that this is a solid strategy that blocks a good amount of the scoring zone.

The kids brought this issue up as well. One of their solutions was to make the robot exactly 120lb by using sandbags in the extensions to help increase the moment of inertia. They also decided to make all 8 wheels high traction wheels to increase the friction to avoid turning. They are going to be excited to see that their ideas were echoed by some more experienced teams.

[staplemonx]

Originally Posted by EugeneF

Cool concept, but I worry about legality.

"BUMPER ZONE – the volume contained between two virtual horizontal planes, one inch above the
floor and seven inches above the floor"

In your starting configuration, the bumpers do not start in the "Bumper Zone."

Good point, we will have to lower the bumpers to line up with the lower support.

[Matt C]

I see no issue with that design. the "bumpers" that come down to enlarge the footprint of the robot are not BUMPERS as defined in the rules. The BUMPERS are only the segments attached to the FRAME PERIMETER. It is only those that must be in the BUMPER ZONE and adhere to the bumper rules.

(Remember that the BUMPERS are not part of the size/weight restrictions of the robot, but your "bumpers" are)

As an inspector, I would not allow this configuration as it stands. If the flip down sections were smaller and fit within the FRAME PERIMETER(when upright), then it would appear to be a legal configuration.

[Snalios]

I would bring it to the GDC, they do have the final word

[GaryVoshol]

It looks like you have some real BUMPERS, and then you have some other padded devices that extend beyond those BUMPERS.

The padded devices are not BUMPERS per <R07> - they don't start in the BUMPER ZONE, they move, etc. Consequently they are not exempt from the weight and size rules in <R11>, and they must be entirely within the vertical projection of the FRAME PERIMETER when in the STARTING CONFIGURATION prior to the match per <R14>. This also means that these padded devices do not have to meet all the conditions of <R07> - they don't have to be red/blue, don't need team numbers, they wouldn't even necessarily have to have a cover at all, they aren't restricted in what materials can be used.

[JesseK]

Originally Posted by GaryVoshol

... don't need team numbers ...

This brings up an interesting topic concerning the display of team numbers on all sides. It's not an explicit rule this year, yet it's an issue the GDC thought would be solved by putting the numbers on all BUMPERs.

I also wouldn't tread in the waters of leaving the external 'bumpers' red or blue -- best to make them black or something neutral if the covers will never be changed. Sure, there's nowhere in the rules that states anything about the colors of external boundaries -- yet if the refs get confused about which alliance you're on ... well that part is a bit vague.

[Matt C]

Originally Posted by JesseK

I also wouldn't tread in the waters of leaving the external 'bumpers' red or blue -- best to make them black or something neutral

HOT PINK

[EricH]

Originally Posted by JesseK

If you're always beyond the Caution line and get turned into the opponent scoring zone by a high-traction high-torque robot, your robot will receive a penalty, per <G32>.

Actually, Jesse, I think no penalty. <G61> is my witness on this. Repeatedly doing that, you might be at risk of a yellow card (repeated egregious behavior--being continually turned into the zone) under <T06>, or penalized if you aren't quick enough to pull out. Trust me, high-traction wheels aren't quite a sure anti-turn method. It may just make the turning uglier to look at.

Given that you fit in the 84" diameter circle, I'd say legal, but risky. I can see a few ways to get a robot past you and score. Based on the top-view drawing, you'd be at 85" and change given a full 38" long starting robot, excluding the bumpers on the extensions (83" given a 37" long starting robot, which is recommended, and definitely over with the end and side bumpers on the extension--92" on a 37" robot base), measured corner-corner because that's the easiest way to check fitting in the cylinder. The cylinder, like the sizing box, is unforgiving. It may help to draw one up in your favorite CAD program and fit the robot into it, if you haven't already.

Sandbags: There are other ways to add weight. If there's any hole in the sandbags, and any sand gets out onto the field, you could be penalized under <G45> (damage to arena by sanding) or <R31> (I know it says lubricants, but it could easily be extended to other contaminants--in fact, it used to include all contaminants, but that's not quite relevant this year because that's past years' rules). Try steel plates instead--they're fairly easy to bolt on, and smaller in size, and won't get all over the field if they come loose.