Chief Delphi - Bumper "Side" Clarification

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- - Bumper "Side" Clarification (http://www.chiefdelphi.com/forums/showthread.php?t=142033)

Re: Bumper "Side" Clarification

Quote:

Originally Posted by MrForbes (Post 1527016)

I guess no one figured out why the maximum bumper height is 12" this year...sigh....

Yes we did, shhh ;-)

Re: Bumper "Side" Clarification

A hard lesson from 2012 :)

Re: Bumper "Side" Clarification \ Vertical bumper?

The legality of non-horizontal bumpers seems contradictory with the rules others are stating. It implies that it is legal to have an 8" vertical bumper, attached to an 8" vertical frame member at the corners, which fits within the 4" and 12" vertical envelope. Does anyone else see this configuration as illegal? If this is legal it allow for a much wider center gap for those doing something in the space between the bumpers.

Re: Bumper "Side" Clarification \ Vertical bumper?

Quote:

Originally Posted by IronMustang9 (Post 1529326)

While the Blue Box below R19 doesn't explicitly apply to your situation, it would stand to reason that the 8" of bumper cover still have to be along your Frame Perimeter, and your Frame Perimeter does not go vertically. It's a question for the Official Q&A, but it somewhat goes against the intent of the rules.

Re: Bumper "Side" Clarification \ Vertical bumper?

Quote:

Originally Posted by CalTran (Post 1529331)

Yes probably a Q&A question. I guess it depends on the definition being used for perimeter, some dictionaries state it means the 2D shape as if looked at from above but others make no distinction and count following a line around all outside edges (3D) including a vertical portion of the edges as being pat of the perimeter. But this may also count as being another 'side' of the robot.

Re: Bumper "Side" Clarification

Quote:

Originally Posted by MrForbes (Post 1527016)

I guess no one figured out why the maximum bumper height is 12" this year...sigh....

If your bumper is at 4", then your bumper would cover the 4.0"-8.5" zone (5" high bumper +/- 0.5")

If another robot's bumper is at 12", then their bumper would cover 7.5"-12.0" zone.

Thus, in a worst case scenario, there is 1" of bumper overlap for the robots to encounter each other.

Re: Bumper "Side" Clarification \ Vertical bumper?

Quote:

Originally Posted by WBCSaint (Post 1526983)

So does the 8" of bumper have to be continuous?

I don't see a rule that requires the bumper to be continuous. However, it is implied that the 8" side must be continuous. So, you could mount one section a 4" high, and another section at 12" high, but the 2 sections must abut each other.

Quote:

Originally Posted by IronMustang9 (Post 1529326)

Nothing requires the bumper to be level. While the rule, as written, says the bumper must be 8", I am virtually certain that the 8" rule will be enforced with respect to the frame perimeter, and not the bumper length.

Re: Bumper "Side" Clarification \ Vertical bumper?

Quote:

Originally Posted by IronMustang9 (Post 1529326)

Yes. I see it as completely illegal within the rules as they currently are. The FRAME PERIMETER is the geometric shape defined by

Quote:

Originally Posted by R2 Blue Box

wrap[ping] a piece of string around the ROBOT at the BUMPER ZONE described in R22.

Quote:

Originally Posted by R22

BUMPERS must be located entirely within the BUMPER ZONE, which is the volume contained between two virtual horizontal planes, 4 in. above the floor and 12 in. above the floor, in reference to the ROBOT standing normally on a flat floor. BUMPERS do not have to be parallel to the floor.

The FRAME PERIMETER is parallel to the ground, so your BUMPERS must cover 8 in. of the FRAME PERIMETER on either side of each corner of the FRAME PERIMETER, not merely have a length of 8 in. R19 makes this fairly clear:

Quote:

Originally Posted by R19

ROBOTS are required to use BUMPERS to protect all outside corners of the FRAME PERIMETER. For adequate protection, at least 8 in. of BUMPER must be placed on each side of each outside corner (see Figure 4-3). If a side is shorter than 8 in., the entire side must be protected by BUMPER (see Figure 4-4). A round or circular FRAME PERIMETER, or segment of the frame perimeter, is considered to have an infinite number of corners.

Quote:

Originally Posted by R19 Blue Box

The dimension defined in R19 is measured along the FRAME PERIMETER. The portion of the BUMPER that extends into the corner is not included in the 8 in. requirement.

The first sentence of the Blue Box is the critical one. It says that 8 in. of BUMPER means an 8 in. projection onto the plane of the FRAME PERIMETER, and does not include the corner that meets the bumper from the other side of the corner.

EDIT: Here's a diagram. The most you can angle your bumpers while still remaining in the bumper zone would be 20.6 deg. for a section that provides 8 in. of coverage.

Re: Bumper "Side" Clarification

I don't see anything in the rules that talks about the vertical backing of the bumper, only horizontal backing. Could I legally have a bumper that ran the whole length of the frame but vertically only slightly overlapped the frame member?

Re: Bumper "Side" Clarification

Quote:

Originally Posted by StephenNutt (Post 1529910)

As long as that slight overlap is fairly solid, I don't think you'd have a problem.

Understand that this is not a blanket OK--I'd actually need to SEE the setup, and some inspectors will test suspect mountings by trying to simulate game interactions. But if you plan carefully, you should be OK.

Re: Bumper "Side" Clarification

Quote:

Originally Posted by EricH (Post 1530008)

some inspectors will test suspect mountings by trying to simulate game interactions. But if you plan carefully, you should be OK.

Like by smacking it? How does one test via simulated game interactions?

Re: Bumper "Side" Clarification

Quote:

Originally Posted by CalTran (Post 1530069)

Like by smacking it? How does one test via simulated game interactions?

Shake it, try to pick the robot up by it, smack it, kick it, step on it... Basically, if the bumper looks shaky, the inspectors may opt to help you out by checking the attachments. You might not even notice.

I have been known to, on occasion, grab and shake the bumper a bit. If it comes up loose, I talk to the team about how a secure bumper can mean the difference between a 3v3 and a 2v3 with one disabled robot. ;) The next time I check, it's usually secure.

Re: Bumper "Side" Clarification

Quote:

Originally Posted by EricH (Post 1530008)

Many thanks for the response - this is good news for us

Re: Bumper "Side" Clarification

Quote:

Originally Posted by CalTran (Post 1530069)

Like by smacking it? How does one test via simulated game interactions?

One test robot inspectors like to use is can you lift the robot by the bumpers? R21-G is subject to interpretation, In the end you have to satisfy the inspector that your robot meets the rules. It is really to your advantage to have securely attached bumpers regardless what the inspector allows. If the bumpers come loose during a match, you will be disabled, maybe penalized, and maybe required to get your robot reinspected. Scout of the teams you want to play eliminations with will take points off your evaluation.

Re: Bumper "Side" Clarification

Somebody's been lurking in this thread. See Team Update 05 for a new BUMPER drawing.