BUMPER PERIMETER

[GaryVoshol]

I haven't seen this discussed much yet. This year we have a new definition, the BUMPER PERIMETER:

BUMPER PERIMETER – the polygon defined by the outer-most set of exterior vertices on the ROBOT (without the BUMPERS attached) that are within the BUMPER ZONE. To determine the BUMPER PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon. The BUMPER PERIMETER may extend up to, but cannot exceed, the maximum ROBOT volume constraints defined in Rule <R11>.

Then we have

Originally Posted by <R08>

K. BUMPERS must protect a minimum of 2/3 of the BUMPER PERIMETER. Teams are encouraged to maximize the area of the ROBOT protected by BUMPERS. But up to 1/3 of the BUMPER PERIMETER may be unprotected to provide flexibility in design options.

L. The BUMPERS must be fixed to the BUMPER PERIMETER.

Teams need to be very careful about how they design their frames. If you have concave sections of the frame, you cannot attach bumpers to that section. In the extreme, consider a robot frame in the shape of a Maltese Cross:
The Bumper Perimeter forms an octagon connecting all the vertices - and the frame touches the Perimeter only at those vertices. There would be no legal way to connect Bumpers to the Bumper Perimeter. Beware!

[Petey]

Originally Posted by GaryVoshol

Teams need to be very careful about how they design their frames. If you have concave sections of the frame, you cannot attach bumpers to that section.

I saw this rule but I did not read this as a cannot. I just read it as a permissive rule--i.e., you can avoid putting bumpers on up to 1/3rd of your bot.

Suppose you had a chassis like this:



Are you saying that you cannot put bumpers on the inside (i.e. the concave) part of the chassis?

Or (and I do apologize for the crudeness of my drawings here),


You're saying that the bumpers in green are legal and the bumpers in red are illegal? Because the way I had read the rule was that the bumpers in green were necessary and legal but the bumpers in red were superfluous but legal.

Or am I misreading you entirely and you're simply making sure that teams know they need to protect 2/3rds NOT of the outside of their robot, but rather 2/3rds of the imaginary line described by the vertices of their robot?

[Nuttyman54]

Originally Posted by Petey

Or am I misreading you entirely and you're simply making sure that teams know they need to protect 2/3rds NOT of the outside of their robot, but rather 2/3rds of the imaginary line described by the vertices of their robot?

Bumpers on the inside are allowed, but will not count as standard bumpers, as they are not mounted to the BUMPER PERIMETER, and as such will not cover 2/3 of robot. Also not that you can't just attach the bumpers at the vertices and have them along the imaginary line that is the BUMPER PERIMETER, as they wouldn't be supported along the entire back side and violate letter M of the bumper rules.

[Petey]

Originally Posted by Nuttyman54

Bumpers on the inside are allowed, but will not count as standard bumpers,

Does this mean that a trailer striking these bumpers would be in violation of the rule that it needs to hit bumper first?

In other words, if the rear of your robot is concave in the way I diagrammed above, and you kept the trailer nestled in close, would it be against regulations because the bumpers within the concave shape are not "real" bumpers because they lie within and not along the perimeter?

This seems like a very confusing rule!

[Taylor]

Originally Posted by Petey

Does this mean that a trailer striking these bumpers would be in violation of the rule that it needs to hit bumper first?
This seems like a very confusing rule!

Yes, which pretty much destroys any attempt to protect the trailer. Yay for offense!

[GaryVoshol]

The green bumpers in the above illustration could count as standard bumpers, with all the benefits and requirements of such: Not included in weight and size, must cover 2/3's of the Bumper Perimeter, etc. The red bumpers would not count as standard bumpers, and must be included in size and weight. Nor would they have to follow all the bumper build rules in <R08>. (Actually, a small corner of each red bumper is outside the bumper perimeter, and would have to be trimmed off.)

Originally Posted by Petey

Does this mean that a trailer striking these bumpers would be in violation of the rule that it needs to hit bumper first?

No, I don't believe so, as long as you're not talking about the trailer you're towing.

In other words, if the rear of your robot is concave in the way I diagrammed above, and you kept the trailer nestled in close, would it be against regulations because the bumpers within the concave shape are not "real" bumpers because they lie within and not along the perimeter?

This seems like a very confusing rule!

If the trailer you are talking about is the one attached to your bot, well Team Update 1 took that away from us. You can't attach the Trailer Hitch in the concave section of the illustration, between the red bumpers, because the Hitch has to be on the Bumper Perimeter.

[Petey]

Originally Posted by GaryVoshol

No, I don't believe so, as long as you're not talking about the trailer you're towing.

That's what I was talking about; our original plan was to store the trailer nestled in that space to help stabilize its motion. But

If the trailer you are talking about is the one attached to your bot, well Team Update 1 took that away from us.

Exactly.

[m^3]

Instead of a recess on the rear to help protect your trailer, what if you made a hexagonal cutout on the front that would that act as a guide to help your robot more accurately dump into an opponents trailer? Is this allowable? We couldn't find any specific rules against it... you aren't attaching to the trailer, only "fitting" up to it momentarily to dump your moonrocks. Bumpers could line the recess, but they wouldn't count as legal "bumpers" and lessen chances of inadvertant attachment or damage to the trailer. Does anyone know if this would be legal? There is a rule that robots must contact bumper to bumper, but what about the trailer?

[GaryVoshol]

Originally Posted by m^3

Instead of a recess on the rear to help protect your trailer, what if you made a hexagonal cutout on the front that would that act as a guide to help your robot more accurately dump into an opponents trailer? Is this allowable? We couldn't find any specific rules against it... you aren't attaching to the trailer, only "fitting" up to it momentarily to dump your moonrocks. Bumpers could line the recess, but they wouldn't count as legal "bumpers" and lessen chances of inadvertant attachment or damage to the trailer. Does anyone know if this would be legal? There is a rule that robots must contact bumper to bumper, but what about the trailer?

I don't see any problems with this, but you should check Q&A to be sure.

You still would not be allowed to contact the upper structure of the trailer, under the liberal <G29> interpretation found in Team Update 1.

[m^3]

Rules update 2 seems to confirm the legality of this, but they note that the bumper rules limit the size of the opening 26" centered on the front of a "wide" robot (minimum 6" bumper on each side of opening).

From update 2, section 8:

In the case of the archetype “wide drive” robot with a centered opening on the front of the robot, this can result in a significant limit on the size of the opening. This limits the ability for incursion inside the bumper perimeter by the trailer. See the example below.

[Jared Russell]

There are still major interpretation issues that need to be addressed by the GDC ASAP.

Namely, the GDC wants us to only put bumpers on the BUMPER PERIMETER, and yet corners must be protected on both sides. This would preclude a LOT of the designs I have seen on Delphi this year.

[MrForbes]

They did address it, in their round-about way.

It appears that half of the robots in the game animation are illegal, because they don't have BUMPERS on both sides of every corner of the ROBOT PERIMETER.