During our inspection problems kept coming out with the way we did our bumpers. In result i have two questions:
Where can i see a list with the full bumper restrictions? Do any of you have one? I remember searching for one with the height of the ground our bumpers can have, without any luck in the manual, and than having it on the inspectors list.
Have the bumper rules ever change since they were first introduced? Is there a possibility that a solution for the bumpers i will find this year be banned by the next?
R03 also defines the frame perimeter wich is important to the bumpers.
Each year, many of the rules change a little bit or a whole bunch. The bumper rules have been around since 2005, with continuous refinement. In 2010, the FRC Game Design Commitee switched over to the Red/Blue configurations with numbers on them. Often there is a change in height from the ground and whether they must be continuous or may have gaps. It would seem that these changes are primarily dependent on the game pieces and how they want the game to play.
Bumpers can be a very frustrating part of the inspection process. There are a lot of detailed rules that must be followed. Often teams that have the most trouble are focusing their design at the limits of the rules. IE, if the bumper length mus be 8" from the corner, they make that segment 8". Unfortunately if the cut is slightly short, of the bumpers don’t fit tightly, you can end up in a condition where your bumpers are only 7 3/4" from the corner of the frame perimeter, and thus non-compliant. My recommendation is that teams add a little margin to their design if they can.
1 - The “BUMPER Rules” section of the ROBOT RULES lists everything specific to the bumpers. For the bumper height, R25 clearly states the “BUMPERS must be located entirely within the BUMPER ZONE, which is between 2 and 10 in. from the floor, in reference to the ROBOT standing normally on a flat floor.”
2 - Expect them to change every year, and you’ll never have an issue at inspection. Read the rules, and figure out your bumper design just like you would your drive train - bumpers are just as important as everything else, and must be constructed legally!
Basic word of advice: If it complies with all of the bumper rules, it probably is legal. If it doesn’t comply with one or more, it is not legal. If you aren’t sure, you’re probably best off asking Q&A about it before you get to your first event; that way the inspectors aren’t either telling you to change it or asking the GDC and then telling you to change it.
I do remember hearing about some weight-transferring bumpers back before the standard bumper design came out (2006); those were effectively banned by the bumper rules in 2008 (standard bumpers were optional in 2006 and 2007).
I mean, given the current rules, it would be legal to use (if you could find it) some 3/4 pieces of ironwood, if you wanted to weigh your robot down for some reason. I even suppose you could weight half your bumpers with a heavy wood and the other half with a light one but I don’t know how much within the spirit of bumpers this is.
Why bother using exotic woods for weight on your bumpers? Just use enough steel in your brackets to get their weight up to 20lbs for the set (if that’s what you’re looking for). There aren’t any rules to using heavy steel blocks with holes thorough them as bumper brackets, so long as you mind the weight limit.
The bumpers are intended for protection and identification. I don’t much like when teams start stretching the rules for some tactical advantage.
Pay heed if I am inspecting (or many other inspectors I know) your robot and you are lawyering or stretching the rules you better have a perfect robot in every other respect because you are going to get the most thorough inspection ever.
I’m not talking about being within the rules, I’m talking about stretching them to the breaking point. Mounting a 10 pound steel plate to a bumper that has no real practical reason is violating the spirit of the rules.
And as far as your second point, in fact, is is the inspectors job to judge if a team is complying with the rules.
Stretching the rules is still complying with the rules. Until it is explicitly illegal to add weight just to add weight (assuming all other bumper rules are met), giving a team a harsher inspection is against the point of inspection. Is the point of inspection not to get all teams on the field, while ensure that they comply with all the rules?
It is the inspector’s job to inspect the robot, they inspect the robot for compliance, end of story.
I just don’t like the idea of turning this into a “battle bots” competition. Playing defense is one thing but to be going into a competition with the intent to “take out” opponents is a whole different perspective.
We built our robot very strong knowing that big hits happen, but we also focus on playing the game not destroying the competition.
Additionally, if you are successful in the competition, you may find it difficult finding alliance members in the finals.
What was the phrase? Oh yeah, Gracious Professionalism.
Yes, but…when teams don’t know some of the rules, they tend not to know others. So while looking at the robot & talking to the team I get the sense that they don’t really understand the basics, I take extra time to make sure they haven’t missed some of the other things. So, if you don’t know how to properly build bumpers (which, despite all the grumbling, are NOT hard) then I wonder if you didn’t read the pneumatic rules either. So I’d better take an even harder look at something that could quickly become a safety issue.
That makes sense. Teams who build bumpers with extra weights typically know that section of the rules more than a given team, not less. If the weights comply with every rule, they clearly know what they’re doing. Does this justify going over their robot with a fine tooth comb?
If they have skirted just to the edge of one section of the rules - perhaps having to weasel-word their way to passing - then what else may they have creatively interpreted? While their creative bumper design is just barely legal, maybe the electrical or pneumatic system is not legal.
I don’t agree that they “…clearly know what they’re doing.” In my opinion teams that add weight to bumpers just to add weight to the robot didn’t read this from section 4.1:
When reading these rules, please use technical common sense (engineering thinking) rather than “lawyering” the interpretation and splitting hairs over the precise wording in an attempt to find loopholes. Try to understand the reasoning behind a rule.
What other parts of the rules didn’t they read?
If I saw weighted bumpers where there is extra material that clearly wasn’t needed as part of the attachment system or doesn’t fit R24, I’d be inclined to think that there could be other places that the team also stretched the rules too thin. So while they were fixing their bumpers, I’d be looking for other things.
And btw…I’ve never inspected a team that added weight to their bumpers just to add weight. This leads me to believe that the majority of teams understand why bumpers are supposed to be there, and reinforces my opinion that adding weight is just trying to find a loophole.
I’m going to be inspecting in Seattle and Calgary over the next two weeks, and have been following the bumper discussions with interest. While final decisions, of course, will rest with the lead inspector, the idea of intentionally building heavier mounts to add weight/shift CoG, is an interesting one.
When I think of the bumper mounts that we built for our robots, we would often use 1/8"x1" steel band iron bolted to the noodle side of the plywood. We’d drill and tap the band iron and run bolts through the plywood and into the band iron, essentially using the tapped band iron as a fixed nut.
Well, would be have been wrong to use 1/4" x 1 1/2" steel? Would we have been wrong to use longer pieces of steel? Would we have been wrong to use 1/2" bolts instead of 1/4" bolts? Would we have been wrong to use four mount bolts at each mount point instead of two? Would we have been wrong to have four mounting points on our bumper instead of three? We probably would have been wrong to use depleted Uranium instead of steel, and using Gold would have put us over the $400 per part… but we could have used Brass to increase the density of the mount.
So we could have easily increased the weight of our mounts by a factor of 8 and still clearly been within the rules, so long as the overall weight was less than 20 pounds.
At some point the mounts might become so large as to reduce the protective nature of the bumpers… for instance if they begin to infringe upon the cross section of the pool noodles… or so long as to effectively violate the diagram (4-4, I believe) showing the cross-section of the bumpers. I think it would be reasonable for an inspector to insist that at some point along the length of the bumper (perhaps even along the majority of the length) the cross-section of the bumpers should match the diagram.
But bumpers that meet the rules meet the rules… even if they intentionally have heavier mounts than are structurally needed… are legal.