Wide C-Base Frame Corners
 

Searched to no avail looking for the answer, but we're currently getting dinged by the lead inspector at the MAR Lenape regional for our c-base frame corners. The exterior corners create a 1"x1" open section as per the assembly instructions for the wide frame configuration.

http://www.usfirst.org/sites/default...de%20Final.pdf

See our robot here: http://www.flickr.com/photos/frc2590...in/photostream

Lead inspector claims that the rear corners have 2 individual vertices, making it a 6 sided robot. Then claims that since there isn't 8" of bumper from each vertex that it's illegal. In my eyes, our bumpers meet up at the "projected" corner and follow rule R28B of not extending more than 1" past the frame perimeter.

I can't believe that if this was truly an illegal configuration that FIRST would supply and then direct you to illegal assembly instructions. Lead inspector didn't address that, just said that "AndyMark isn't FIRST". Though true, the c-base is in every KoP with the included instructions for assembly.

He told us to stick something 1"x1" in the corner to make those 2 vertices turn into 1. We taped a piece of 1" tube into the corner - seems ridiculous.

Any thoughts / relevant rule interpretations / Q&A questions?

Re: Wide C-Base Frame Corners
 

That's not right, and should be legal. If they keep complaining, cut a piece of pool noodle and put it in there.

Honestly though, ask for another inspector. That is the way the kitbot is made, and the way we made our kitbot. If the kitbot is deemed "illegal", then that is the inspector's fault.

No offense to the inspector, but the kitbot should be legal.

Re: Wide C-Base Frame Corners
 

FIRST is not perfect all the time, I remember being caught by inspectors because our bolts for our wheels on the c-base extended out past the frame (now they have the 1/4 inch policy). Well an easy way to fix this would be to cut some longer pieces of c frame that are 1 inch longer on each side so you have the frame mount nicely and make a 90degree corner. This may work for your front since those are probably short pieces anyway. But the back piece seems like the max dimension for a c-frame. Well, is it feasible to slide your outer two pieces in one hole? This would make a 90degree angle, but I am not sure how the internals of your ball manipulator and shooter are put together. If not look into adding something to fill that gap.

Re: Wide C-Base Frame Corners
 

Even though I agree that the frame should be legal, I always show respect for the inspector's decision, they are there as volunteers and I appreciate all they do for FIRST. I suggest to just find a way to fix it.

Re: Wide C-Base Frame Corners
 

Ask for the Lead Inspector, not just any other inspector. That way you get the final word, and someone else to deal with the inspector who made the call in the first place.


steelerborn, that bolt catch is a "standard" rookie mistake. That wasn't a FIRST mistake. That was a team's (hopefully rookie) mistake; the rules don't give a bolt head allowance in the sizing box, but do for the frame perimeter. (The C-base as currently produced makes a 37" square robot before being cut down to FRC size.)

Re: Wide C-Base Frame Corners
 

If you guys have any problems competing tomorrow, look for Chuck DiVincenzo and tell him Cory sent you in his direction. I will shoot him a text regarding the situation and they might bring up some c-channel from their room and I'm sure teams will have 1/4-20 fasteners for you. They will make sure you guys compete.

Re: Wide C-Base Frame Corners
 

The lead inspector is correct.

Those are exterior vertices, and therefore the frame perimeter is as he describes. Bumpers must be supported at their ends (with "ends" as defined by the inspectors—there is no objective standard), and must protect both sides of each exterior vertex of the frame perimeter (around 2009, there was more ambiguity about whether protection implied bumpers on both sides of a vertex—this year, [R27] is clear about this).

The solution he proposes is a good one—indeed, probably the best one.

By the way, be cautious about [R28B]. When it says 1 in, there is no tolerance—or rather, the tolerance is MAX 1 in, measured along the projection of the edge. Even if you prevailed on the vertex issue (which you shouldn't), if your notched corner left a span of even 1.01 in, you'd be in violation. I suggest measuring the C-Base again to make sure that it's not slightly more than the 1 in you're assuming it is.

FIRST made a small mistake by failing to warn teams about this. Nevertheless, this doesn't rise to the level of FIRST misrepresenting the situation—after all, those (third-party) instructions aren't held out as being official documents, and the official rule is sufficiently clear.

If and only if it satisfies the definition of frame perimeter as required.

Not really. Also, they're already dealing with the lead inspector. There isn't any higher authority. Short of having the LRI removed from their position—which frankly isn't going to happen over a mere judgment call, right or wrong—they don't have any higher avenue of appeal. Only the officials and FTA can make the call to FIRST HQ for assistance with a ruling, and even then, it's their prerogative alone.

That's something to take up with FIRST after the season. I hope they listen, because it's very reasonable for the rules to be written with the kitbot in mind.

Re: Wide C-Base Frame Corners
 

EricH: Yes, It was the first ever time we had a 100% student CAD team design every piece of the robot, We had planned for 1 inch of extra space on each end of the bot, however we had an issue that pushed us to the max dimensions. The bolts did fit in the sizing box (barely) but the way we had designed the bumpers that year (big mistake scrapped it immediately after that) gave us some issues.

My main reason was just to state that there is sometimes something that you don't plan for that can happen during inspection. But by tackling those challenges in the heat of competition helps you learn that mistake, how to fix it, and also grows your team much closer together. I apologetic for my miss-wording of my previous comment.

Re: Wide C-Base Frame Corners
 

Unfortunately, Tristan is correct on the letter of the rules - having an open 1"x1" gap on the corners of the robot does not permit legal bumpers or bumper support. It something I noticed on our robot in week two or three, and we cut up an old frame to remake two of the rails extend into those corners. We did it to ensure there would be no issues with inspection at any events.

That said, there is the letter of the rules, and the intent. Teams have been making their frame with that 1"x1" gap in the corner for years, and it hasn't had any noticeable impact on bumpers. While there are undoubtedly some inspectors out there who will stick to the letter of the rule (and the LRI's are forced to stick to the letter of the rule as its been handed down by the GDC), many more will not even notice that issue on the corner, as they're so used to seeing it built that way for every robot every year.

As far as bumper problems go this year, though, this is one of the easiest ones to fix. All you need is to stick something in the corner - even bolting a thin piece of sheet metal over that corner will technically define your frame perimeter as you expect.

Other issues, like those with bumper numbers, length of short bumper segments, and sufficient backing of short segments that are hanging over ball openings, are all much more difficult and time consuming to fix. If this was the worst problem you had during inspection, then you did better than half the teams out there!

Re: Wide C-Base Frame Corners
 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Step 1: take some flat, bendable material like a piece of sheet metal, thin (1/8" max) polycarbonate, cardboard, or even heavy paper** if you must.

Step 2: cut one 4"x1" strip of said material for each corner where this is an issue.

Step 3: fold each strip in half to get an "L" that measures 2" on each side.

Step 4: Glue, bolt, rivet, secure with mounting tape, velcro, or zip-tie in place.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Congratulations, you have now re-defined your frame perimeter to make your robot legal by the letter of the rules.

**a very strict inspector might not count paper since the flexibility allows for some noticeable change in shape which could be considered to be a violation of the requirement for the frame perimeter to be non-articulating.