Bumpers

[Mac Generals]

Hey, does anyone know if we are allowed to make the bumpers bigger? (for example: 3 or 4 "noodles" in height instead of 2).
Also has anyone found anything about minimum height of the bumpers off the floor?

[Alan Anderson]

It's all in the 2009 FRC game manual, Section 8 - The Robot. Get it here: http://www.usfirst.org/community/frc...nt.aspx?id=452

Read rule <R08> to find out the legal bumper design, noting where it uses the word "must", and looking at the definitions of CAPITALIZED words earlier in the manual when necessary.

[Mac Generals]

we understand that the rule is in the manual we simply had a disagreement and wanted a sepreate interpetation of the rule.

[GaryVoshol]

You'd have to ask the official Q&A to get an official interpretation.

[AndyB]

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

B. BUMPERS must use a stacked pair of 2-1/2 inch “pool noodles” as the bumper material.

C. Each BUMPER segment must be backed by a piece of 3/4-inch thick by 5-inch tall piece of plywood.

So your bumpers must be contained in a zone 1" and 7" off the ground. That gives you 6" of height to work with. Bumper noodles must be 2.5" in diameter. Even if you found a way to interpret the words "stacked pair" as being more than 2, you can't physically fit more than 2 noodles vertically in a 6" space. Even if you somehow get past this, your backing needs to be 5" tall.

I hope that answers your question.

[Mac Generals]

thanks for the help it is much apreciated

[Vikesrock]

Originally Posted by Mac Generals

we understand that the rule is in the manual we simply had a disagreement and wanted a sepreate interpetation of the rule.

Bumpers must be built exactly as specified in the manual including two stacked 2.5" diameter pool noodles.

If you feel that your robot needs further protection you are welcome to build additional protecting structures above the BUMPER ZONE into your design. These structures could be functionally identical to bumpers bu they would not be BUMPERS and would thus need to be counted in your weight and volume restrictions. They would need to be mounted so that the outside edge of these custom "bumpers" does not exceed your bumper perimeter.

[Urban Hawk]

i disagree with the fact you can't get a larger bumper. Although as andyb said that it must be within the bumper zone, the bumper zone is merely the the hight it has to be in, not the horizontal restriction; that horizontal restiction is defined by the definition of a pumper paramiter which is: (BUMPER PERIMETER – the polygon defined by the outer-most set of exterior vertices on the ROBOT (without the BUMPERS or Trailer Hitch attached) that are within the BUMPER ZONE.) and by rule <R08>N which states(BUMPERS may extend beyond the BUMPER PERIMETER by up to a maximum of 3-1/2 inches per side. “Hard” parts of the BUMPER (i.e. plywood backing, fastening system, and clamping angles) may extend up to a maximum of one inch beyond the BUMPER PERIMETER. Only “soft” parts of the BUMPERS (i.e. pool noodles and cloth covering) may extend more than one inch beyond the BUMPER PERIMETER.).

Yet think about it this way... what if you make the bumpers within the bumper parameter. that is to say if you have a robot smaller then the maximum size, and add another piece to the robot (such as a spring mechanism so it wouldn't be damaged). If that piece resides within the bumper zone, yet which is not part of the bumper, and that piece extends all the way out to the max dimensions then technically by the rules you can build the bumper so that the bumper starts at the normal frame of the robot and then extends out to the max parameter + 3 1/2 inches. under that method u can increase the horizontal dimensions of the bumpers by a few inches as long as it stays in the 18 pound weight limit.

[EricH]

Originally Posted by Urban Hawk

i disagree with the fact you can't get a larger bumper. [...]
Yet think about it this way... what if you make the bumpers within the bumper parameter. that is to say if you have a robot smaller then the maximum size, and add another piece to the robot (such as a spring mechanism so it wouldn't be damaged). If that piece resides within the bumper zone, yet which is not part of the bumper, and that piece extends all the way out to the max dimensions then technically by the rules you can build the bumper so that the bumper starts at the normal frame of the robot and then extends out to the max parameter + 3 1/2 inches. under that method u can increase the horizontal dimensions of the bumpers by a few inches as long as it stays in the 18 pound weight limit.

If I understand you correctly, you don't understand the rule.

1) The bumper perimeter is defined by wrapping a string around your robot in the bumper zone at the largest points (Section 8.2). You have to put your bumpers on this point (<R08-L>). If you dynamically change your bumper perimeter during the match, your bumpers must go with it (early Q&A). So if you have a spring, the bumpers must follow the spring outwards, whether it's deployed before or during the match.

2) <R02-N> states that bumpers may extend beyond the bumper perimeter up to 3.5" per side. This has been clarified in Q&A that this is normal to the bumper perimeter plane. This includes: 2.5" of pool noodles, 0.75" of plywood, and miscellaneous hardware. That is 3.25" without cloth or hardware (like, say, the clamping angle).

[Urban Hawk]

when i talk about that spring mechanism i mearly mean something that can take the blow with the bumper so you either dont get it snaped off on impact or be compleatly stiff and have it take the entire force of the blow from the robot rather then the bumper. it would not be somthing not something that would change

(i have to turn off computer and head back to my house so ill answer second part of question when i get back on there)

[EricH]

Originally Posted by Urban Hawk

when i talk about that spring mechanism i mearly mean something that can take the blow with the bumper so you either dont get it snaped off on impact or be compleatly stiff and have it take the entire force of the blow from the robot rather then the bumper. it would not be somthing not something that would change

(i have to turn off computer and head back to my house so ill answer second part of question when i get back on there)

In other words, an articulated bumper. Just be sure you expand the bumper perimeter accordingly.

[Urban Hawk]

to better explain what im thinking i made a model on microsoft word though its not very good

[EricH]

Originally Posted by Urban Hawk

to better explain what im thinking i made a model on microsoft word though its not very good

Now I understand. Just be warned, this configuration would potentially be illegal. Here's why.

1) We will assume that sections A-F of <R08> are met. This will greatly simplify life (though <R08-E> would be hard to meet).

2) We now face <R08-G>. "BUMPERS must attach to the ROBOT with a rigid fastening system to form a tight, robust connection to the main ROBOT structure/frame (e.g. not attached with Velcro!). The attachment system must be designed to withstand vigorous game play – nut and bolt fasteners are recommended. All removable fasteners (e.g. bolts, locking pins, pip-pins, etc.) will be considered part of the BUMPERS." This is not a problem if the frame moves with the bumpers. If it doesn't, you have to redesign your bumpers.

3) Next up: <R08-I>. (<R08-H> is presumed to have been satisfied.) "BUMPERS must protect all exterior corners of the BUMPER PERIMETER (see Figure 8 - 2)." You've got a gap wide enough to take a hit in those corners. In other words, I'm not sure they're protected.

4) <R08-J> and <R08-K> are presumed fulfilled.

5) <R08-L> reads, "The BUMPERS must be fixed to the BUMPER PERIMETER." If the perimeter is mobile with respect to the rest of the chassis, you're probably fine. But if it isn't, the bumpers aren't legal.

6) <R08-M> means your frame must go with the bumpers.

7) <R08-N> through <R08-P> are presumed fulfilled.

You're questionable at best. But, there is also one other thing to consider. <R18>, the trailer hitch rule.

<R18-B> means that you have to have that section solid with respect to the robot, not movable. So you make arrangements to have the rest of that side move, bringing you into violation of <R08-D> and possibly <R08-E> In other words, if that side moves, I would bet that many inspectors won't let you through.

At best, 3 sides of the robot could do that. But it's a risky proposition under the rules. You'd have to make sure of all your rules being satisfied. If even one of them isn't, then you won't be allowed to compete.