pic: Legal Frame ????????????????
 

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I would ask the Q and A for an official ruling, but my understanding is that the bumper perimeter has to be a convex polygon as defined by the definition of frame perimeter:

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This has come up in past years and was not allowed, but you could always try running it past the Q&A again.

This is kind of on that same track:
http://forums.usfirst.org/showthread.php?t=15188

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If that "T" had any concave areas, it shouldn't have passed inspection.

This looks illegal. A FRAME PERIMETER cannot be concave (barring the allotted cutouts)

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You are correct Chris, and in the FIRST Forums thread there they talk about how it should not have passed.

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i would say yes as long as the bumpers are ok.

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Then you might want to spend some time reading the robot rules. Specifically, see Section 1 of the Game Manual, read the definition of FRAME PERIMETER. Also study section 4, specifically the information about bumpers.

http://usfirst.org/roboticsprograms/...nt.aspx?id=452

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That's very interesting considering your signature. The FRAME PERIMETER of this frame would be a rectangle with the 4 outermost vertices as corners. The bumpers need to be placed along this FRAME PERIMETER with the maximum unsupported distance being 8".

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We were the team that had the tee design last year and won an award for it at our first event. At the first event the ref's questioned the design but concluded that they couldn't see that it was positively in violation of any rule. But asked if we would ask the GDC to verify and we did here: http://forums.usfirst.org/showthread.php?t=15188 As you can see they never responded even after many phone calls. We showed up at our second event and they told us we couldn't compete. We could have fixed it in the fix it window if they had responded. But instead were forced to fix it at the event. Redoing the frame and bumpers was not easy.

The whole thing was handled very badly with FIRST. I was very sad to see the rule in the rule book again this year. It is a very confusing rule that really should just say "no inside corners are allowed"

After much arguing at the event they finally told us what part we were in violation of. They interpret it as: The outer-most exterior vertices (aka corners) are the perimeter. Thus if you have an inside corner it is not outer-most and thus is not allowed. :ahh:

They tell us not to lawyer the rules but then they don't write them like an engineer would and it forces us to lawyer them.

Here are this years rules:
BUMPER PERIMETER – the polygon defined by the outer-most set of exterior vertices of the BUMPERS when they are attached to the HOSTBOT. (To identify the BUMPER PERIMETER, wrap a string around the BUMPERS at the level of the BUMPER ZONE - the string describes the polygon.)

FRAME PERIMETER – the polygon defined by the outer-most set of exterior vertices on the HOSTBOT (without the BUMPERS attached) that are within the BUMPER ZONE.

In blue: To determine the FRAME PERIMETER, wrap a piece of string around the HOSTBOT at the level of the BUMPER ZONE - the string describes this polygon. Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

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I'm an engineer, when I read the rules it's easy for me to understand that they mean "no inside corners".

If you're not an engineer, yeah, I can see how it could be confusing. Although it was discussed to death here on CD....

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Apparently it is better to not have a concave bumper system than to have an aluminum mechanism drop down after start to give the same desired contact design. That will mean other robot will be running into our mechanism through the match and the bumper behind it will be just for looks and rules

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We had already asked the GDC about this design (yes, we thought of doing it as well). The answer was no.

http://forums.usfirst.org/showthread.php?t=16259

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You got an award for blatantly breaking a rule?

I understand it's by no means your fault, and you obviously didn't mean to, but how could that happen in FIRST?

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We couldn't get penalties for the soccer balls going more then 4 inches under the robot because the robot/frame was only 4 inches wide. That idea is what we got the award for.

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It's not likely that many judges have studied the rules...they are not the robot inspectors, after all.

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what about a curved bumper?

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I find it odd that they are taking away creativity when there is an award for it! I personally don't see the harm in having a concave design. Where is the fun in building a box (rectangle) on wheels? Our team is known for doing things in a strange way!! We love that about us. Joe should be on the GDC because of his creative mind. He has inspired dozens of kids being a "wild and crazzzzy guy"!! The kids are bummed but we will go build a nice box on wheels!!

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You don't have to create a box. You simply have to have all external corners. A triangle is perfectly legal. A trapezoid (Wider on one side, narrowing down) is allowed. There are a number of shapes that are perfectly legal that don't break any rules. Obviously, I'm not a part of the GDC, I have no bearing on the rules, but I imagine that the idea is to reduce the risk of entanglement and to ensure that things aren't going to be as easy to break.

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The string example was in the rules last year, it is a simple rule and if you REALLY struggle with doing it in your head get some freaking string and drive some nails into plywood. If the string doesn't touch the nail it isn't a valid vertex on your bumper perimeter.

As for it being handled poorly at FIRST's end I have to agree, the inspectors at your FIRST event should not have allowed you to compete at all and it sucks that they lacked the understanding of the bumper rules. I was at that event and I also saw teams competing without batteries secured down and with black bumpers. I admit, my brother got sick of my picking at least one team a match that shouldn't be allowed on the field because they shouldn't have passed inspection. (This was Saturday and is only a SLIGHT exaggeration)

You're right, but it is hard to give a robot that isn't on the field an award and 326 should NOT have been on the field.

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Thats actually really clever (and also illegal) considering how many of those penalties that got called in week 1. Are there any pictures of it?

I remember at MARC you had a triangle-ish frame, right? You were also the biggest steal of the alliance selections, too....

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This judge always did :D

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You start down a slippery slope if you allow "pointed" bumpers. Ramming another bot with a point wouldn't do now, would it?

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Easy to break? So not true. I can build my V but not have it part of the frame or in start up. I can run all over the place with it sticking out, mind you that would be dumb of me but I can still do it. When the match starts up I could have it come out as long as I am within there specs.

I remember the T bot. I went to Ann Arbor to watch the game. It was pretty cool!!

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The same way teams get rewarded after posting how they design their robot, send the plans to their sponsor, and recieve a kit back with all the parts cut, brackets bent and metal skins laser cut. A simple bolt together and they are hard to compete with.

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Deleted--double post

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There is NO RULE saying that that is illegal. If that is how the team chooses to conduct their design and build, that is their business. I don't know of a single team that does that, BTW. The bumper rules are clear-cut (or mostly so, with some recurring "is this legal" Q&A questions that are typically answered quickly and clearly).

squirrel, one of the judges at Arizona last year was doing inspections on Thursday. Just for reference...

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You mean the robot that they put in hundreds of hours prototyping, designing, and entering into CAD in meticulous detail? Some teams emphasize the physical shop work of putting a robot together, but it is by no means a requirement of the competition. The process these teams go through is likely far closer to an actual real life engineering process than what your team does or what mine has done in past years.

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All that design must be so easy, huh. All they have to do is make a perfect CAD model of their entire robot exactly as it will work, then they have to assemble, test, and try again if something isn't perfect.

Sounds like a walk in the park to me.

The teams you're not so subtly referencing have earned every award they've ever got - and taught their students more about engineering than a thousand lessons on how to use a mill.

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One is against the rules, the other is completely legal. Do me a favor and delete this post, we can have a little chat about this topic on Monday and if you still feel this way I will fully support you in posting this in a new thread that it is more relevant to.

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I'd like to point out-- I didn't say that a "T" bot (or any other robot that breaks the current rules for bumpers) is "easy" to break, I simply pointed out that it would have a greater potential to be damaged, or to damage other parts. I'm not saying that's the reason, but there are reasons for these rules. We may not be privy to all the information, and we probably don't like it, but that doesn't change the fact that it's most likely there for a perfectly logical reason.

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One judge out of how many, about 20? I'd say it's very unlikely that more than 10% of the judges at any regional know the rules well enough to perform robot inspection. It's not their job. It's the robot inspectors' job.

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I didn't have time to count the number of judges. Being short-handed and then behind schedule does that to ya...

You're right, it's not the judges' job to know the robot rules well enough to inspect. But I wouldn't be terribly surprised to find that quite a few inspectors (or former inspectors, or refs, or mentors) are judges across the country. If we're counting "general idea, but can't cite the exact rule or knowledge a year or two old", then you might get up to about 25%.

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We probably have pictures around... At our first event we had all the refs and inspectors come look at the bot... That was our first order of business... They found nothing wrong at that point... Like Mr. G said we were not given any advantage, just trying to avoid penalties... But hey we made the change when asked too...

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My standard advice:

Stop whining about something that can be fixed by working harder.

Teams that have the resources to do lots of prototyping, design their entire robots in CAD, send the parts to machine shop sponsors, and assemble completed robots are the way they are because of a lot of hard work. These resources and relationships did not just fall in their laps. These teams provide their students a very engaging and rewarding opportunity to work with engineers and companies, to participate in an advanced engineering design process, thoroughly ideate and test prototype ideas, understand topics like manufacturability and limitations of various fabrication technologies, see how using CAD software significantly improves the final robot, and much, much more.

Instead of whining about these teams, recruit engineering mentors. Recruit machine shop sponsors. Fundraiser throughout the year to afford lots of prototyping. Learn and become fluent in CAD software. With enough hard work, any team can become a top tier team.

How do I know this is possible? When I first joined 228, we had about eight students and an annual budget of about $12k. Last year, our budget was probably among the top quarter percentile of FRC teams, we had identical practice and competition robots with parts made at our school, at two sponsor machine shops in Connecticut, and at one sponsor machine shop in California. We attended three official events and took home a Regional banner and Regional Engineering Inspiration award. We bucked the traditional advice against never designing a swerve for the first time during the build season, and did just that (and even made it able to drive over the bump), and other than a bearing defect issue (out of our control) got it working within the six weeks build. And we worked our collective buts off for the entire year, both inside and out of the six week build, to fundraise and get the resources in place to make all that possible. Our goal has never been to whine about the top tier teams, but to become one.

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The rules clearly define the FRAME PERIMETER, but stop short of saying that the bumpers cannot go inside of this perimeter. Ask on the FIRST site and hope for a clear answer.

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Actually <R07-K> says that.

Emphasis mine.

Also <R07-A>.
I think it would be the logical conclusion that the bumpers must be on the outside of the FRAME PERIMETER in order to protect it.

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I have been an engineer for over 30 years, and in Section 4, I see the definition of a perimeter. It would have been much clearer just to add that the bumpers must continuously touch this perimeter. Hopefully we will see this in an update, as I suspect many teams would like to use the "V" design in the original post to help center the robot on the tower base. The people at FIRST have a tough job in writing rules, but not giving any hints or design directions.
Jim

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They turned us down. We figured it was a 50/50 chance. I have to give the people of FIRST a lot of credit for giving us the answer on a Sunday. That was the point of the "V" to line up at the pole. One of the kids already have something up their sleeve to solve it!! :D

The same way teams get rewarded after posting how they design their robot, send the plans to their sponsor, and recieve a kit back with all the parts cut, brackets bent and metal skins laser cut. A simple bolt together and they are hard to compete with.

I say more power to them!! Last year we had 2 engineering students on the team ( still do) and we won the Excellence in Engineering Award at both districts we went to. Again it is because we have crazy imaginations that we encourge in the garage. We make our parts ourselves and we don't have ANY fancy machines and our budget is right around $1,200 for the year. ANYTHING is possible. :D

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But this isn't true - there are allotments for bumpers going over various sized gaps in the perimeter.

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OK Ladies and gentlemen,
Time to quote the rules from Section 01 Introduction...
FRAME PERIMETER – the polygon defined by the outer-most set of exterior vertices on the HOSTBOT (without the BUMPERS attached) that are within the BUMPER ZONE.

To determine the FRAME PERIMETER, wrap a piece of string around the HOSTBOT at the level of the BUMPER ZONE - the string describes this polygon.
Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

This kind of says it all. Language similar to this was the rule last year as well. Hold a string around the frame and that describes the FRAME PERIMETER. The FRAME PERIMETER must be protected by bumpers and this year the rule under Section 04-The Robot R07-K allows some leeway that was not present last year, i.e.some gaps and some unsupported bumpers. The "T" robot last year and "hourglass" robot shown above fall under the same rule. A string wrapped around the robot at the height of the bumper zone would bridge the opening and therefore require bumpers attached to the robot everywhere the string exists. I failed a "T" design last year for the violation. I explained the rule and assisted the team in becoming compliant. As they were under size and underweight and had time to complete the needed mods, they played. In light of other game rules, (cough herding cough) it is easy to see why the FRAME PERIMETER is so defined.

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It doesn't say the string has to be taught.....You could pull the string around the robot much like a seamstress would use a measuring tape to measure in their job. I took the string as more like a level line.

It is the exterior vertices part that means you can't have inside corners.

Not to argue this anymore, but this is just a badly written rule. It would be much better to just say "inside corners are not allowed"

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I disagree with the phrase of "inside corners" as I had to read a fair amount on this thread to know what that means. However, adding the word taught would be a much better solution.

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Kevin,
Not to be hard on this but it doesn't say "wrap the string around your frame and push it in where ever the frame goes in". It simply says "wrap the string around... ". The above rule is specific to 2011 only and does not allow for interior corners. If the GDC changes the interpretation, I will inspect for that new definition.

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Definition of wrap

wrap verb
a : to cover especially by winding or folding
b : to envelop and secure for transportation or storage : bundle
c : enfold, embrace
d : to coil, fold, draw, or twine (as string or cloth) around something

Al, I am just having fun now, but I disagree per the above definition. When "wrapping" an oddly shaped present you would cover each segment as I have stated for placing the string around the robot.

Cheers.

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Kevin,
Good thing I am in a good mood today.
Good Luck!
Al

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Sorry for venting. I have asked to have the post removed. But, most teams do not have the option of shipping off a design and have the parts made for them. I was only referencing a post I saw last year. FIRST is about the journey...but most of the awards are based on final product.

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Except that paper would not be touching the interior vertices. Instead it would be touching the outside vertices of the concave polygon. Any frame that is a concave polygon is illegal because all of the vertices on the polygon are not touched when you wrap a string around the bumper perimeter. I don't like the rule but I also don't like several other rules, doesn't mean I can break them.

If you want to align yourself consider making an asymmetrical frame and deploying a single bar out. That way half your force is taken by the bumpers. Alternately if you are just worried about another robot ramming it you can place it up in the air and only deploy it when you are going to score. Or you can just build it strong enough to take hit... you know, like we had to do back in the day when we didn't have these fancy bumper things.

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Teams including my own have worked very hard to secure the ability to get stuff machined off site. We have a small sponsor that churns out CNCed parts like no one else and we're very grateful. It took my team tons of work to come up with what little resources we had.

What makes you think the teams you are referencing just had these sponsors fall into their lap? What makes you think if you're not standing by the mill as it's running you're not trying, or you've somehow done less engineering?

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Kudos to all the teams that can accomplish this. I was responding to the post about an illegal robot getting an award, and the poster wondering how it can happen. My point is I believe there is a bit of a contradiction between the mission of FIRST and the way awards are won.