Re: 2nd Most Awaited Q and A Answer?
 

I agree what you have here is a common sense interpretation, one that I believe most teams have been operating under for the past 3.5 weeks.

This response seems to completely contradict the common sense interpretation put forth above by JamesCH95. This is what frustrates me when people start saying "don't lawyer the rules, just use common sense". Well, sometimes the common sense of the community and the common sense of the GDC aren't the same, nor should we expect them to be. Different people will always have different interpretations. In this case, since the rule wasn't unambiguously spelled out in the manual, and since Q&A's weren't fully addressed, we're now 58% through the build season and being given a ruling that will significantly alter the designs of many teams. The teams who didn't "lawyer" the rules and used their own common sense are now the ones who will be forced to make major changes.

I can't see any justification for why this rule is being interpreted this way. I'm hoping that this is just a misinterpretation, similar to the issue we saw with the reference plane of the bumper zone earlier this season. If not, a lot of teams are to have to make a lot of changes, and a lot of inspectors are going to be forced to enforce a rule they'll have a very hard time justifying to the teams.

They don't call it the hardest fun you'll ever have for nothing. Just another challenge.

Re: 2nd Most Awaited Q and A Answer?
 

I will be suggesting to my team tonight that we put a retractable cap on our appendage. To be lifted off of the appendage after the joining point has clearly exceeded the frame.

Re: 2nd Most Awaited Q and A Answer?
 

I was thinking more about this today and made a grave realization that these two Q&A Forum answers just painted FIRST into a corner that will make nearly all appendages illegal.

What this means: if you follow these two Q&A rulings strictly, all wheels, gears, sprockets, rollers, or any other type of rotary motion device (with an axis of rotation parallel to the frame perimeter) on an appendage are now illegal.

Why?

There will always be a portion of the wheel, gear, or sprocket that is dis-contiguous from the rest of the appendage for the small duration of time between which the edge of the wheel, gear, sprocket, roller, etc breaks the plane of the frame perimeter and when the shaft breaks the plane.

Photos are worth a thousand words:

Image 1: What common sense would define as a contiguous appendage. In this case, it's a simple wheelie bar that extends straight outwards. The grey part is the robot base, the black side is the frame perimeter. The light red, blue, and green parts are an appendage that comes straight out. This appendage is entirely inside the frame perimeter and is legal.




Image 2: The appendage has started to break the frame perimeter and extend outward! This is a section view of the CAD assembly, looking outward from the frame perimeter. So far, so good. The appendage is contiguous.




Image 3: The appendage has continued to expand out, but it's now illegal! The portion of the wheel that has broken the plane of the frame perimeter is now dis-contiguous (outside of the frame perimeter) from the rest of the appendage!




Image 4: The appendage continued to expand outwards, and the axle of the wheel finally broke the plane of the frame perimeter! The wheel is now 100% contiguous with the appendage outside the frame perimeter again and is legal once again.




As these images very clearly show, unless the FRC GDC intended to ban all wheels, gears, sprockets, or rollers with a axle/shaft parallel with the frame perimeter, there must be an exemption of the contiguous mandate for appendages in the act of deploying.

There is a very simple solution solution to this fix this problem: only require the appendage to be contiguous outside the frame perimeter when it contacts or reacts with some element on the playing field.

Re: 2nd Most Awaited Q and A Answer?
 

Art
You are exactly correct. That would be a noncontiguous deployment under a strict interpretation of the QA answer...

However, it could also be interpreted that the entire assembly including the wheel or gear is the appendage. If this is true, then the appendage would be contiguous outside the frame perimeter.....otherwise you could not put it out... because there would be two appendages....for a brief time...

This is, in essence the same issue with a rotating roller with small stubs of tubing on it... what IS the appendage??? Is it the entire unit? or bits of the unit as they move over the perimeter?


this is really getting ridiculous isn't it?

Re: 2nd Most Awaited Q and A Answer?
 

Art,

Clearly the wheel and it's supporting structure are the same appendage. In Image 3 it is obvious that the portion of the frame perimeter crossed by this appendage is contiguous. Whether or not that's how the GDC wrote it, that's clearly (IMO) what is intended.

Re: 2nd Most Awaited Q and A Answer?
 

Just in case you weren't following this question on Q&A, here's another response on this theme:

Q. Thanks for the additional G21 clarification. I would appreciate a bit more clarification, primarily regarding your 2012-01-27 response to FRC0063. Can more than one component of a contiguous appendage assembly outside of the frame be simultaneously crossing one edge of the frame perimeter? Thanks.

A. Yes, provided any part of the appendage that is outside the Frame Perimeter is contiguous.

Re: 2nd Most Awaited Q and A Answer?
 

From the answers the Q&A has given, i don't see the image of the wheely bar as described above or an H-shaped appendage, as violating the rules about appendages. Here are the questions and answers again:

Game - The Game » Robot Actions » G21
Q. Our question is similar to FRC1540. We want to put surgical tubing "whips" on a roller located at the frame perimeter. When this rotates the whips will extend beyond the frame perimeter. Is each "whip" its own apendage or is the assembly considered one appendage? FRC3219 2012-02-01

A. If multiple items exit the Frame Perimeter and are not contiguous outside the Frame Perimeter, they are considered multiple appendages.

Game - The Game » Robot Actions » G21
Q. To prevent differing interpretations of G21 and the following Q&As on appendages could you address the legality of a appendage BRIEFLY crossing the frame perimeter in multiple places during deployment? For example, a "H" shaped appendage might cross in two places as it quickly folds out. FRC1540 2012-01-30
A. Any time the appendage is outside the Frame Perimeter, it must be a contiguous piece.

Q. Thanks for the additional G21 clarification. I would appreciate a bit more clarification, primarily regarding your 2012-01-27 response to FRC0063. Can more than one component of a contiguous appendage assembly outside of the frame be simultaneously crossing one edge of the frame perimeter? Thanks.

A. Yes, provided any part of the appendage that is outside the Frame Perimeter is contiguous.

From the first answer our appendages have to be continguous outside of the frame perimeter. From the second answer our appendage has to be a contiguous piece when it's outside the frame perimeter. From the third answer more than one component of a contiguous appendage assembly can be simultaneously crossing one edge of the frame perimeter.

The way i interpret this is that our H shaped appendage is fine as long as when the appendage is fully deployed our cross member is located outside the frame perimeter. The second answer only means that two separate things can't join together to form one appendage after each breaks the frame perimeter, or that they can't separate after they've broken the frame perimeter (they stay one contiguous piece outside the frame) The answer doesn't say that an appendage can't cross the frame perimeter in multiple places. The third answer says that it can, as long as the multiple places are contiguous with eachother, not neccesarily contiguous outside of the frame perimeter.

So when the 2 ends of the H are going outside the frame perimeter 2 components of a contiguous appendage are crossing the frame perimeter. The appendage is contiguous while being deployed, and when the H is fully deployed the cross member is outside of the frame perimeter making it one appendage.

Re: 2nd Most Awaited Q and A Answer?
 

Austin, that's the common sense interpretation.

The problem is, that's not necessarily what the GDC said.

Can more than one component of a contiguous appendage assembly outside of the frame be simultaneously crossing one edge of the frame perimeter? Thanks.

A. Yes, provided any part of the appendage that is outside the Frame Perimeter is contiguous.


To put the answer another way, if it's outside, and part of a contiguous assembly, the part that's outside has to be the contiguous part.

To be fair, you could apply the "is contiguous" to either "any part" or to "appendage". That's probably where we're differing--we're applying it to the "any part" and you're applying it to the "contiguous".

Re: 2nd Most Awaited Q and A Answer?
 

I read this latest response as allowing "U" shaped appendages where the solid portion is facing outwards. No big surprise there. Those cross the frame perimeter in two places but are contiguous when outside of the frame. There's nothing about this that allows "H" shaped appendages (during deployment) in my estimation. My original question to GDC mentioned that specifically and they disallowed it.

Re: 2nd Most Awaited Q and A Answer?
 

I zeroed in on this dilemma earlier in this thread, when I questioned how the contiguity test would be applied. My "common sense" told me that any "appendage contiguity test" would ONLY make sense if it was applied EXCLUSIVELY to ONLY those portions of a deploying appendage that were progressively crossing and occupying the OUTSIDE SPACE of the boundary of the frame perimeter.

The only portions of a robot component that can be considered or evaluated as an appendage, are those portions which HAVE EXTENDED BEYOND the frame perimeter, and their contiguity assessment CANNOT consider ANY PORTION of the(se) component(s) that REMAINS INSIDE the frame perimeter -- only what PROTRUDES BEYOND.

The reason that the contiguity test "path" COULD NOT be allowed to be traced crossing back INSIDE of the frame perimeter, is that, since all parts of a robot are normally contiguous to the robot inself, there has to be an imaginary demarcation PLANE to merely establish the concept of discontinuity. It is then in relation to this demarcation plane of the frame perimeter that we can evaluate the contiguity of what has protruded beyond it.

This was how I came up with the lightsaber test concept, that artdutra04 has so nicely illustrated in the image below:



I like the suggestion that no appendage be assessed for contiguity until it contacts the field, field elements, or an item (non-robot) that is in contact with the field or field elements. Otherwise, LEGAL appendages have just become a whole lot less capable than what we thought they could be!

-RRLedford

Re: 2nd Most Awaited Q and A Answer?
 

Here is the definition of contiguous from:
http://www.merriam-webster.com/dictionary/contiguous

1
: being in actual contact : touching along a boundary or at a point
2
of angles : adjacent 2
3
: next or near in time or sequence
4
: touching or connected throughout in an unbroken sequence <contiguous row houses>

Could we use definition 3 to solve this whole problem. "Next or near" would solve all the problems of not touching when taking cross sections and "in time or sequence" would help with the deployment process as a whole. If the appendage moves all parts touching or not in the same sequence it would be considered contiguous. It seems to me if we have this definition on hand as proof at competition no inspector or head ref would be able to rule against us.

Re: 2nd Most Awaited Q and A Answer?
 

This is what I thought all along...it's pretty obvious to me....

Re: 2nd Most Awaited Q and A Answer?
 

#3 def is more related to temporal considerations with a touch of motion implied. There is a concept of "contiguous motion" that might be applied.
#4 is more related to the connecting physicality of objects assembled together.

-RRLedford

Re: 2nd Most Awaited Q and A Answer?
 

Thanks. We're legal (it's more a "D" than anything else), but for anyone who is looking only to the robot rules or inspection checklist, don't forget G21. As a ref, this is all very painful. At least inspectors get to slowly look at one robot however they'd like. I shudder at what could be required of refs in terms of G21. Will the inspectors take care of it all, or do we need eagle eyes to tell which edge/component crossed the perimeter first? What if I see a partially obscured Y/V/U and mistake it for two "1"s?

Note that this only applies if the shaft is parallel to the frame perimeter plane (or angled but not long enough). Perpendicular shafts should be fine. (This also applies to H's that are vertical or I-shaped crossing the perimeter.) Well, both should be fine, but perpendicular shafts are fine even accepting ridiculousness.

Re: 2nd Most Awaited Q and A Answer?
 

I'm just adding these two new Q&A responses here for those who aren't following Q&A's on the topic. Nothing really new:


Q. It seems the appendage definition Q&A started out innocently requesting clarity, but led to being over-scrutinized. I suspect the intent of G21 is that an appendage is simply “a contiguous assembly of parts originating from inside the frame and can extend beyond one frame edge 14”.” Please confirm.

A. There is no formal definition of appendage. All pieces of an appendage outside the Frame Perimeter must be contiguous outside the Frame Perimeter.


and


Q. The appendage confusion stems from two conflicting replies: 1) “an appendage is a contiguous assembly that may extend beyond the frame”, and 2) “an appendage, when extended beyond the frame, is a contiguous assembly”. It seems reply #1 is your intent and in the spirit of the rules. Please confirm.

A. Both answers are the intent of the Rule.