Bumper Inspection Discrepency
 

At Alamo, our bumpers passed inspection with flying colors and were even complemented by many inspectors for how effective they were. They are one single assembly that we slide over the top of our robot into slots in the frame.

At Peachtree, we were informed from the beginning that our bumpers were illegal. The butt joints created by the wood at the corners of the bumpers were ruled not legal. We reconsulted the rules and figured that under <R07> L, "Hard" parts of the BUMPER (i.e. plywood backing, fastening system, and clamping angles) may extend up to a maximum of 1" beyond the FRAME PERIMETER." made us legal.

The inspectors called FIRST headquarters, who said that our bumpers were illegal, as wooden backing may only extend the length of the horizontal projection. We spent the next few hours removing the bumper fabric, cutting off the butt joints with the reciprocating saw, installing angle brackets on the inside of the bumpers, and reassembling the fabric. It was annoying, to say the least, and made our bumpers much less attractive, much less structurally sound, and was just an overall pain. we were annoyed that they called this, yet allowed teams to pass who's bumpers dragged on the ground, were ziptied on, and even some without numbers on all sides. But ok, I do not fault the inspectors as the ruling came from FIRST headquarters.

I was just curious, have other regionals been calling teams on this? I just wanted to let other teams who built their bumpers like us to be prepared for this possible ruling. How does everyone else interpret this rule? We plan to remake our bumpers for North Carolina...

Re: Bumper Inspection Discrepency
 

<R07-D> is what they probably were calling you on. That's the bumper segment length rule. The exception to <R07-D> is <R07-C>, soft stuff in the corner.

"Quick" solution for North Carolina: Wrap the pool noodles around the corners, but don't put wood into the corners. If anybody complains that that's illegal, point them straight to <R07-C>, where that method is explicitly allowed. Then use the frame attachments that you did before.

If they were passing teams that had blatantly obvious and relatively easy to fix bumper problems (ground clearance, numbers, and non-secure fastening methods), while enforcing a rule that's tough to enforce and tough to fix non-compliance, there's another problem there. All the rules are rules, not just the ones that you want to enforce.

Re: Bumper Inspection Discrepency
 

I can't tell you about this year but if I understand what you are describing, they would be illegal this year for the same reason they were illegal last year.

If you check the Q&A's, if something is legal by one rule but illegal by another rule, then the more restrictive (illegal) rule takes precedence. In this case the 1 inch extension for R07 "L" may be OK, but the more restrictive Joints between BUMPER segments and the radial projections of corners must be filled with “soft” BUMPER materials. from R07 "C" takes precedence (emphasis mine).

Re: Bumper Inspection Discrepency
 

Remember that for a completely-overlapped corner constructed to the theoretical maximum dimensions, the distance between the outermost vertex of the bumper backing and the nearest point on the frame perimeter is:

0.75 in × sqrt(2) = 1.061 in

Since this exceeds the 1 in clause of the rule, that construction is technically illegal.

In fact, the rule doesn't prohibit overlapping backing corners in general (by virtue of not mentioning them at all), it merely prohibits this degree of overlap. To confuse matters, it actually requires teams to fill the corners with soft materials—and this could be read to mean that the entire corner must be soft.

Additionally, the statement "wooden backing may only extend the length of the horizontal projection [of the frame perimeter]" is a bit dubious. The maximum length of a segment cannot exceed the "maximum horizontal dimension" (unclear whether that's a diagonal across the frame, or a side length), but this doesn't say anything about overlap. Further, although there is a requirement that "a full segment of BUMPER must be placed on each side of the corner", it's not clear whether that means the segment must begin at the vertex, or merely whether each side of the corner must be adjoined by such a segment.

Re: Bumper Inspection Discrepency
 

As a mentor for the team in question, this ruling was beyond annoying and just added to the already generally poor inspector quality at the Peachtree regional. Our bumpers had pool noodles in the corner and did not have any hard surfaces sticking out. We merely created our bumper backing as one solid piece so that it would be robust and the simplest connection possible. Additionally this does fall within the rules as we use baltic birch sold nominally as 3/4" plywood but it is in reality 18mm thick.

Re: Bumper Inspection Discrepency
 

Unfortunately, inspection discrepancy is almost the norm. Everyone does their best, but, as you see in the Q&A every year, the rules can be interpreted differently. Further, inspectors really only get a limited amount of time with each team, and can easily miss something. I can't count the number of times we've had an inspector at our second regional make us file some sharp edges the first inspector hadn't noticed, or other small items like that.

Personally, when we're going through the build season, I'm always trying to read the rules in their strictest possible interpretation to ensure we don't get hit with anything at inspection. It doesn't always work, but I can definitely say that it helps.

Re: Bumper Inspection Discrepency
 

I've wondered about the reasoning behind that corner rule. I can plusible think of two reasons:

1) The case where a robot is hit hard right at the end of the bumper with the overhanging plywood and the plywood on that side pushing the adjacent side's plywood laterally, risking shearing off the attachment hardware.

2) If the bumper with the long plywood should happen to become detached at one end, but still secured at the other, and it gets tangled up with stuff, the bumper will act as a lever and potentially push the adjacent side board and shear off its mounting hardware.

Basically, I think its because they want the bumper segments (at least the hard parts) to remain independent and not 'react' with each other so that failure of one bumper doesn't cascade into potential failure of an adjacent bumper -- the above are specific cases of that.

I do know at least one team was cited for the same reason at Lake Superior Regional at least initially.

John Vriezen
Team 2530 "Inconceivable"
Mentor, Drive Coach, Inspector

Re: Bumper Inspection Discrepency
 

Having been intimately involved in bumpers over the past 4 seasons, I went back and checked previous manuals. Figure 8-4 was in the 2010 manual but is missing this year. They were very specific about this last year, but not this year.

Re: Bumper Inspection Discrepency
 

I think this probably bit a fair number of teams coming out of Alamo. I know it also bit 3103, Iron Plaid, when they were inspected at Lone Star. They had the exact same butted construction pass at Alamo, and it too was ruled illegal in Week 3, but at Lone Star. Which is frustrating because I help those girls out and I posed this EXACT question to the GDC and got what I THOUGHT was a go ahead for it. I'm not really sure how else I was supposed to take this exchange on the Q&A:
I ended up assuming the positive second paragraph was the answer. Apparently I should instead have stuck with the non-answer first paragraph and told Iron Plaid that the none of the Q&A answers actually have any bearing whatsoever on how the rules are actually administered at competition. And thus.... something.

Which is sort of the problem with some of the GDC's non-answers to questions that should really be fairly easy for them to answer. Especially because there apparently IS an answer from FIRST HQ on the legality of Option 1 there.

You'd think they might have told me that two months ago when I asked.

Yes, I know the GDC doesn't want to get bogged down with making 200 specific rulings on 200 specific design questions that are actually covered by the rules. That's why I went to all the trouble of laying out my reasoning and interpretation of R07-K and R07-L in the question. I did, in fact, want them to clarify one or both of those so we could all understand the intent and move on with our lives. That they completely failed to do so while declaring that was what they're there for was somewhat less that impressive. That someone up there apparently DID have the specific clarification I was hunting for is just a bit annoying.

I like to think that all my questions of the GDC have a purpose and point to specific areas of the rules in need of clarification, but they clearly don't agree. So, if anyone with inside information is reading this, I'd really like to know exactly how I AM supposed to word my questions so that they'll get an actual response instead of the form letter "we don't rule on specific designs". If I have to format them all in abstract terms with no reference to any proposed design, I'm willing to do so. I think it makes the whole thing that much harder to understand, but I'll do it just to get some reliable answers out of them.

Re: Bumper Inspection Discrepency
 

For the reasons noted (Figure 8-4) and my previous position on the matter (see my December post) and the GDC's position that a one piece bumper is OK, I directed my team to miter the wood corners as well.

At Florida, our LRI cited <R07-D> and wood in the corner was prohibited.

I blame myself rather than the system. I should have posted to the GDC on this issue. Sometimes you think you are right and don't bother to ask...

Oh well...

Re: Bumper Inspection Discrepency
 

The problem is that the GDC has not officially ruled on this and it was just up to there discretion once we got to our second regional to say that we were illegal even though there was no performance gain or anything from our system. Functionally our bumper is 100% identical to similar bumpers constructed with angle aluminum in the corners.

Re: Bumper Inspection Discrepency
 

My biggest concern with the ruling was less with the rule itself but more with what was allowed. We had inspectors come into our pits even before we began the inspection phase and began looking at our robot and bumpers. From listening to the conversation...most of the inspectors seemed to think the bumpers were fine but ONE inspector decided they wern't and had FIRST headquarters called and thats when we got the news that the bumpers were in fact illegal. So we argues and showed R07L but it was still deemed illegal by FIRST headquarts. So whatever....we fixed the bumpers and were on our way.


What REALLY annoyed the living crap out of me was seeing teams with dragging bumpers...HUGE V gaps in all corners, no team numbers, fabric that was hanging off, and viptied to the frame of their robots. When i brought this issue up with the inspectors i was told "we needed to get teams out there and passed inspection so we let it slide" WHAT THE HECK IS THAT?! so a team that is prepared is more likely to be scrutinized than teams that didnt?

what i learned from this....inspect late...better chance they will let you slide.

Re: Bumper Inspection Discrepency
 

Lucky for me I did ask the GDC specifically about wood in the corner and got back a vaguely affirmative answer, so I can totally blame the system. I'll only fault myself for not following up and pressing for an actual answer from them. I know that's sometimes necessary and I should've realized this was one of those cases.

Re: Bumper Inspection Discrepency
 

Fundamentally, if the inspectors do something that's really annoying, but in line with the rules, how should fault be apportioned?

Undoubtedly there's an element of inspector's discretion involved—and the rationale for applying that discretion varies greatly from inspector to inspector. And maybe the team ought to have read the rules a little more closely. But in my view, the majority of the responsibility has to lie with FIRST: they make the rules that everyone needs to follow, and when they err, everyone feels the repercussions. Most teams are making a genuine effort to comply, and most inspectors are making a genuine effort to bring teams into compliance (without punishing them, if at all feasible). Obviously FIRST is trying hard too, but it's their competition and therefore their ultimate responsibility.

Was the one the lead inspector? It's part of their job description to determine whether FIRST needs to be consulted—it's not exactly a vote.

I suspect that attitude is more prevalent when dealing with bumpers than with other rules. Everybody hates bumpers to some degree (except maybe the GDC?). At any given event, if there's one place you're most likely to see deviations slipping through, it's the bumpers. It's not ideal, but neither is the bumper rule.

Also, as we've seen here (yet again) this problem has a cascade effect. The team then attends another event, where the enforcement ends up being a bit more strict, and it's a difficult situation all around.

(When you compare the difficulties in complying with the entire bumper specifications from any of the past several years to the meagre benefits derived from the bumpers, you find that bumpers are usually a dreadful value proposition. It's no wonder people are so contemptuous of that particular rule.)

Also a better chance they'll make you fix something, and you'll miss your first match as a result. (Remember, don't even show up with a human player in that case; your alliance will kill you.) Depending on your team's level of risk aversion, that might not be a sensible game to play.

Re: Bumper Inspection Discrepency
 

I have no problem with bumpers. They are kind of a pain to make, but they do their job and the red/blue/number thing makes it so much easier to figure out which robot is which, and which alliance it's on.

We've never had any inspection issues with them at all. We do our best to figure out just what the GDC really wants (it is very simple as I see it), we don't try to do anything fancy, and it works out fine.

Re: Bumper Inspection Discrepency
 

We were the first team inspected at lake superior and they went over our 'bot like they were inspecting a nuclear reactor, but that is fine with me, we are a veteran team and should know the rules. Every year there are a half dozen teams at each regional that make me feel real sympathy for the inspectors. Just looking at their 'bots, you can tell the issues to getting them passed are huge. I think we veterans have to either help them get passed or look the other way when they slide through. Hopefully they learn something and figure it out by next year.

Re: Bumper Inspection Discrepency
 

I agree taht veteren teams should help in all ways possible, but i dont think "looking the other way" sends the right message. It says that a lesser robot should get sympathy and should be allowed to break the rules. Many of the same issues that are goign on in our government policies....but before i get political..ill stop before ...::ouch:: ::ouch:: ::ouch::

Re: Bumper Inspection Discrepency
 

You should ask FIRST, just as a general inquiry and without pointing any fingers at officials or teams, what they're doing about rules that are perennially difficult to fully comply with. I wonder whether the GDC has established a plan to improve upon those rules for the future.

I'm curious about this statement; the Chit-Chat forum is always available for these sorts of things....

Re: Bumper Inspection Discrepency
 

At a lot of events the first robot to be inspected is used as hands-on training/refresher for the inspectors by the lead inspector (LRI). I wouldn't take any offense from it.

Re: Bumper Inspection Discrepency
 

As the Lead Robot Inspector at the Alamo Regional, I stand by our decision and I would approve to pass your bumpers again, referencing this same exact rule. While I did not personally inspect your bumpers, I agree with the inspector's decision who did this at the Alamo Regional.

However, if the Lead Robot Inspector at the Peachtree Regional found something that was specifically not allowed in the rules (possibly a different rule), then their decision at that time must be followed, like your team did. If there is indeed a specific rule that we did not catch at the Alamo Regional, and we should have told you about this, then I am sorry that this was missed. Reading through this thread, I still don't see a clear explanation of why your bumpers would be illegal. If anyone can clearly and effectively show how this is illegal, please do this so we can all be educated.

If you (or anyone) wish to pass along more information to me via PM, I can possibly help alleviate this situation.

Sincerely,
Andy Baker
LRI at Alamo Regional & Boilermaker Regional
Inspector at Midwest Regional & Smokey Mountain Regional

Re: Bumper Inspection Discrepency
 

With regard to the 1 piece bumper, it is pretty clear to me they are legal in general, but can't have any wood sticking out past the corner thus making yours illegal. I have attached a view of our bumpers to show what I mean.

In addition, the attachment also has a view of the metal frame we made to be legal and have a one piece bumper. Note that we do not show the pool noodles in the diagram but is is obvious where they should go.


Credit has to go to team 118 for the idea. They had a one piece bumper last year and at the 2010 Lone Star Regional they were kind enough to show me how they did it. I knew right then that it was the ONLY way to make bumpers. Our pit crew and drive team are very thankful that team 118 asked that clarification last year and showed us their design.

Re: Bumper Inspection Discrepency
 

Guys,
I am guessing the answer came from this rule...
D. BUMPERS segments must have a minimum length of six inches (as defined by the
BUMPER backing), and a maximum length that does not exceed the maximum horizontal
dimension of the ROBOT (except for the soft cushion in the corner, as permitted by Rule
<R07-C>).
We have allowed teams to make one piece bumpers that do not violate any other rules. Paul's design is but one that appears to be legal.
Please remember that the 1" hard parts rules is a cross sectional rule as defined in Fig 4-1 extending out from the robot frame. As always, inspectors are concerned that no hard parts exist in the corners that can damage another robot. Sorry that you got passed at one regional and caught at another. We are trying hard to make things consistent across all regionals.

Re: Bumper Inspection Discrepency
 

We were called on this at the Finger Lakes Regional as well, during the second inspection before elimination rounds. Why it was missed during the initial inspection, we will never know. I know a second team was also advised to fix their bumpers as well. After understanding the rules, we fixed the two offending bumpers, pulled them apart, cut off 3/4 inch of wood off of each end and re-wrapped them.

A bit of a pain, yes. But we were the ones who mis-read the rules, so we have no real reason to complain. And since our bumper design is one of the simplest possible, they still look just as good as before.

To me, it does no good to look at other teams bumpers to say that we weren't treated fairly. Our team's expectation is that we do our best to be professional and focus on making our robot the best it can be regardless of the status of the team's around us.

Re: Bumper Inspection Discrepency
 

A couple of points

1) There are several differences in the bumper rule wording between last year and this year, but I think they intended them to be the same. One problem is the omission of Figure 3-2 (which should be 4-2) referenced in rule R07-C. If that were the same as Figure 8-4 from last year (which I think it was intended to be) that should have answered any questions. Rule R07-O from last year is omitted this year, but replaced by R07-C and D where you could see the same intent although not as clearly.
2) I think there is some confusion between one-piece construction and continuous construction. When the GDC said that nothing prohibits one-piece construction, they are correct; you can attach all of your bumper segments together into a single unit. However, you cannot make the backing continuous because that would violate R07-C by having hard material in the radial projection of the corner. You would have to make that joint by crossing behind the corner diagonally above or below the robot frame.

Re: Bumper Inspection Discrepency
 

lucky for us, we just add new bumper.

Re: Bumper Inspection Discrepency
 

All,

I have started a thread on the LRI discussion board within the FIRST Forums. Hopefully, we can get some more clarity on this issue.

I honestly thought that rule L allowed this overlap to happen this year.

Andy

Re: Bumper Inspection Discrepency
 

Our team interpreted the bumper rule as allowing overlap, so we also got called on that immediately at Chesapeake. I'm glad we got it fixed then so that we can go into Connecticut without having to worry about it. It's hard to keep the bumper rules straight from year to year - I do think that the rules were a bit difficult to decipher this year.

Re: Bumper Inspection Discrepency
 

Thanks for checking into this. We really appreciate it. Of course we will change it if FIRST indeed clarifies the ruling but it really seems to be allowed based on the rules this year. Also there is no difference in performance, it is just easier to fabricate this way for us. Why bother with the added complexity of angle if you don't have to.