Bumper Restrictions
 

During our inspection problems kept coming out with the way we did our bumpers. In result i have two questions:
1) 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.
2) 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?

Re: Bumper Restrictions
 

Please check section 4.1.6 of the manual for bumper rules:
http://frc-manual.usfirst.org/viewItem/3#4

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.

Re: Bumper Restrictions
 

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!

Re: Bumper Restrictions
 

it is just that i have an idea for a little more- tactical-bumpers and i wanted to know if they were legal. anyway thanks for the answer. i hope it won't be a one trick pony before first restricts it.

Re: Bumper Restrictions
 

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).

Re: Bumper Restrictions
 

The bumper rules are actually quite self-explanatory this year, with the major changes being 3 points:

1. Hex and Star pool noodles are now allowed
2. 3/4" thick durable wood is allowed, rather than just plywood, and
3. Team numbers can be split across bumper gaps

Of course, I have to ask, knowing that I will probably regret it... What the heck is a tactical bumper?

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

I don't think this is fair. If teams build their bumpers within the rules, and you don't agree with the rules, why should the team get a more difficult inspection?

It doesn't matter if you like it or not, if they comply with the rules, it is not your position to judge.

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

IMHO:
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.

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

I really don't understand why the bumper rules are such an annual sticking point. Anybody with some fabric, pool noodles, plywood, and a staple gun can build legal bumpers in an hour or two.

Re: Bumper Restrictions
 

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?

Re: Bumper Restrictions
 

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.

Re: Bumper Restrictions
 

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:
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.

Re: Bumper Restrictions
 

We have just recently added some steel bumper attachments/supports to the rear of our bumpers to effectively shift the center of gravity some.
Why? because its legal and it's what need

They already capped people being too crazy with weight by making a weight limit...I'm following said limit and not stretching anything.

Re: Bumper Restrictions
 

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.

Jason

Re: Bumper Restrictions
 

They're a problem for so many teams every year because teams ignore/forget about them until the last minute. Everyone is so focused on getting the robot built, that they don't bother with bumpers until the last minute, and even at that point they stick their least-capable students on it while everyone else focuses on the "harder stuff".

If more teams thought about bumpers earlier, and spent the time to make them right, then they wouldn't be a problem for anyone. For my team, we had one of our best students sign up to do bumpers, and she started on them a week before Stop Build Day... after she finished designing and building our climbing arm. The bumpers are reversible, look great, and can be mounted quickly (in fact, they mount quicker than any other set of bumpers we've had). Treating the bumpers as equally important as any other part of the robot leads to them looking just as good as the rest of the robot!

Re: Bumper Restrictions
 

This may be slightly off-topic, but we saw a team with bumpers that were in the bumper zone, but not parallel to the ground. After reading some of the Q/A, it seems like they have to match the vertical cross-section shown in the manual which seems to make them illegal. Does anybody know for sure if these bumpers are legal or not?

Re: Bumper Restrictions
 

I do agree that when a team stretches or bends rules, the inspectors should look more closely at other things... if you're willing to twist the rules how you like in one instance, you're likely willing to do it again in other places!

However, I disagree that adding weight to bumpers bends rules or requires any careful reading of the bumper rules. I just re-read the bumper rules and really didn't find a thing that made me feel iffy about adding weight (especially in the form of beefier brackets or reinforcments) to bumpers.

Given my experience with bumpers for our robots, it seems to me that every team should be able to make strong, legal bumpers for their robot that weigh 15 pounds or less. Why then has FIRST raised the weight budget for bumpers up to 20 pounds? Seems to me that FIRST isn't trying to get every team to have the same weight bumpers by having a high budget. If team's want light bumpers, make them light (while strong and legal!)... if team's want heavy bumpers, make them heavy (while legal and hopefully strong enough!).

Re: Bumper Restrictions
 

Yes, they're legal. So are bumpers that are on more than one level, as long as they're totally within the bumper zone. Search the Q&A; I believe both were asked & answered.

Re: Bumper Restrictions
 

On the topic of inspectors giving more detailed and exacting inspections to robots that "stretch the rules" regarding bumpers:

Do you inspectors actually have differing levels of inspection for different robots that you like or don't like? Are you actually in the habit of giving some robots a cursory inspection while going over others with a fine tooth comb? If so, what exactly is your reasoning for this? I'm curious, because I can't think of any reason to do only a cursory inspection on an uninspected robot. Unless you've worked with a team, you can't possibly know how well that team knows the robot rules. I've run across some very veteran teams that have missed things on inspections. And I've run across some LRI's (myself included) that have skimmed the rules and missed a detail or two. I'm pretty sure it benefits everyone to treat all robots the same and give everyone a thorough inspection.

So again, why exactly are you giving some robots less than a thorough inspection?

Re: Bumper Restrictions
 

You're making some pretty big assumptions. Who said anything about "like" or "don't like"? That potentially implies that there's some favoritism based on the team; I sure hope that's not what you meant. And who said "cursory"?

"cursory" vs. "thorough" != "thorough" vs. "double-check"

I can't think of a good reason to ever do a cursory inspection on an uninspected robot either.

Re: Bumper Restrictions
 

If there is a team at the regional that I "like" or "don't like", I don't inspect them - inspectors have to be impartial, so we don't overlook things. As LRI at events, I have to like every team.

No team gets a cursory inspection - every team gets the full inspection. Some teams may be given a harder time, however... You'll treat a rookie team differently than you do a Hall of Fame team - There are different levels of expectations. Besides, it's fun finding issues with those great teams :p

Re: Bumper Restrictions
 

Prior to competing in robotics, I led a high school electrathon race car team. While discussing vehicle tech inspections with a high school drag race team, the high school drag racing coach told me about the importance of washing and polishing the car before tech inspection. The first benefit was that it made sure that everyone went over the car carefully, but the second benefit, as he saw it, was more significant...

"When the inspector approaches the car, from fifty feet away, they can see that it shines. They can see that we take pride in the car and care about little details. By the time we pop the hood and they look at the clean, shiny engine, they are already thinking 'this team has it together'!"

Did they still get inspected? Yes. Did they still have to meet all the rules? Yes. But the difference was that the inspector expected them to pass from the moment they laid eyes on the car.

It probably shouldn't make a difference... but we're all human and all subject to 'first impressions'. Thankfully FRC has some good processes in place to help ensure a level playing field... the inspection checklist, a well-developed set of rules, and a good Q&A system. Perhaps more importantly is that there is one Lead Robot Inspector at each event who works to ensure uniform inspection processes and correct rule interpretations.

So I think I speak on behalf of many inspectors when I say that we look for the same things on every robot... but that the inspection can go much more quickly when teams have clearly met all the criteria and laid it out in a logical, tidy, organized way for everyone to see, rather than having a tangled mess of unlabled wires jumbled together with pneumatics lines buried underneath an opaque panel.

The goal, after all, is to see everyone compete, with a safe, reliable robot that meets all the rules.

But you already know all that... and I get the point that you're making that everyone should have the same "level" of inspection... I think the point that the previous inspector was making was that just as teams can do things to make inspection go efficiently, there are things that they can do that make it take longer.

Jason

Re: Bumper Restrictions
 

Introducing the Van Halen contract and the no brown m&m's clause. Not because they didn't like them, but if you didn't read and comply with that tiny part of the contract, you might not have read the part that their stage production weighs several tons and could sink your stage. As lead singer David Lee Roth said in the Snopes link:

Re: Bumper Restrictions
 

Thank you for all the well thought out replies. I'll admit the "cursory" wording was stretching things a bit. My primary concern was with the appearance of bias in this post:
It seems like the opposite of the effect dtengineering is pointing out. An inspector notices something that rubs him the wrong way, and suddenly he's expecting to find other things wrong and is looking in much more detail for anything, however small, that might be out of spec. Or atleast that's the way that reads to me.

I ascribe to the philosophy that the inspectors are there to verify that teams are legal to compete and help teams get legal if they're not. Comments like the above don't really fit that notion and cast inspection as an adversarial process with teams trying to get away with whatever they can and inspectors trying to catch them at it. Which leads to unnecessary conflict, stress, and nitpicking interpretations of the rules.

For instance, we had an inspector once that wouldn't take our word that our home depot 12ga THHN wire was 12ga. He declared it felt too thin and wanted to see the labelling buried in our robot. After snipping a sample from our spare wire he declared it the thinnest 12ga he's ever seen. He then went on to criticize our abbreviation of our school name BTW-HSEP, declaring it could mean "By The Way, He Sucks Early Peaches". And when we started writing the full name in smaller letters (Booker T Washington and the High School for the Engineering Professions), he declared that it was neither proud nor prominent. At which point I flipped the sign over and scribbled the name on the back just to make him happy and get my kids on the field. This kind of madness and stress is what comes of couching inspection as an adversarial process. Bayou addressed the issue when we filed a complaint, to their credit, but I'd really rather it hadn't happened in the first place.

Re: Bumper Restrictions
 

If the rules say they can do it then it is the inspector's job to pass them. Causing teams problems just because you don't like what they did within the spirit of the rules is wrong.

In my opinion (inspector at more than a number of events) our job is to inspect for adherence to the rules. Failing that, we inspect for adherence to the spirit of the rules. We ensure safety and fairness. Every team had the option to strap 10lbs of steel to their bumpers so it's completely fair.

Re: Bumper Restrictions
 

While I certainly agree with the fact that inspectors should actively seek to pass robots that are in compliance with the rules, I do want to take a bit of issue with the final sentence.

Teams did not have the option to strap 10lbs of steel to their bumpers. Teams did have the option to design ridiculously heavy bumper mounts... but unless that mass is somehow involved in connecting the bumpers to the robot, it is not allowed under the bumper rules. It is a subtle difference, but not an insignificant one. To allow a team to just come along mid-competition and bolt ten pounds of steel onto their bumpers might be unfair to those teams who took the time to read the rules, assess their design options and then integrate heavy bumper mounts as a design choice.

I tend to agree that inspectors should interpret the rules to the team's benefit as much as possible... but there are limits.

Jason

Re: Bumper Restrictions
 

I agree with you on this, and I think most inspectors (unlike the one you reference later) agree.

That's terrible, and I'm glad you took the time to complain. I'm sure that many complaints against inspectors are unjustified (I'm *really* upset that you wouldn't let me use MDF as bumper backing) but I'm also sure that there are some legitimate complaints that don't get reported & therefore don't get addressed.

AWESOME! Thank you for the link; I'd never heard of this but it's a perfect example. I hope I don't have to pay you royalties every time I reference this. :D

Re: Bumper Restrictions
 

I was using the verbiage in the quoted thread. I assumed it was hyperbole.

Re: Bumper Restrictions
 

Fair enough! :) I just had pictures of someone naievely reading one post and saying "It's okay to strap ten pounds of iron to the bumper! I read it on Chief Delphi."

But I like the example of the "thinnest 12 gauge wire I've ever seen". We had a similar issue in '06 when we used speaker wire for many of the longer wire runs (downstream of the speed controllers only, of course, so colour was not an issue). We were actually one gauge "over", using 10 AWG where 12 was required, etc.

The inspector didn't like the speaker wire one bit... and if it were easy to replace the wire we would have done so without complaint... but it was pretty "built in", so we asked if it would be okay to get the LRI's opinion. The LRI wasn't sure so he asked the tournament director. Eventually the question went all the way to FRC HQ, and came back on Friday morning that there was no rule against it, so it was legal... thus supporting the inspection credo that if it's not illegal or unsafe, then it's fair game, even if you don't like it. (Later the inspector apologized for the hassle and explained that he'd had some negative experiences with speaker wire when using it in a different application that made him feel it was unsuitable for FRC.)

Although it made for a stressful Thursday night, we did go on to win the Sportsmanship award at that event. I think it was due mainly to the kid's great efforts over Friday and Saturday... but it couldn't have hurt that we were polite and respectful during the whole inspection process Thursday despite our rather extreme concern at the potential of having to rip our entire machine apart, and said "Thank you for checking" rather than "Told ya so!" on Friday morning. :)

Jason

P.S. Haven't used speaker wire since... it's got nice soft insulation, and is fabulous to work with, but the benefit isn't worth the potential hassle.

Re: Bumper Restrictions
 

Well, all those brown m&m's will have to go somewhere... :)