<R12> 72" x 72" Size Restriction

[AcesPease]

The 72" rule is not an unreasonable restriction and may help you to a more stable arm design.

[Kevin Sevcik]

Originally Posted by boiler

The rules are simple. Your robot may, during normal play, not exceed 72" X 72". Use your GP, stay within the confines of the rules, don't try to bend or break these rules and everything will be fine. Yes, some rules make the game hard - that's the point! With each limitation comes a new challenge, another opportunity to show off your team's ingenuity.
Personally, I would hope that refs would never have to whip out their 72-inch measuring sticks - if the robots are designed respectfully within the given boundaries, there won't be any problems.

Again, my only question is if it's a 72"x72" box you have to fit in, or if you paste something on your robot that says "72" this way, and 72" that way."

[Richard]

Originally Posted by Kevin Sevcik

Again, my only question is if it's a 72"x72" box you have to fit in, or if you paste something on your robot that says "72" this way, and 72" that way."

I expect the inpsection checklist will have a line item corresponding to <R12>. The test will probably be to place the arm or extension so that it is at its maximum reach, then verify that the robot still fits within the 72" wide x 72" deep limit. Of course, passing this test will not ensure that an arm is legal. Safety is always the paramount concern, and <R03> clearly says that an otherwise-legal device on a robot can be disallowed if, in the judgement of the inpsectors or referees, it poses a hazard.

[Brandon Holley]

i think this rule is good, arms could get out of control...but then again this is FIRST :-P

[Kevin Sevcik]

Originally Posted by Richard

I expect the inpsection checklist will have a line item corresponding to <R12>. The test will probably be to place the arm or extension so that it is at its maximum reach, then verify that the robot still fits within the 72" wide x 72" deep limit. Of course, passing this test will not ensure that an arm is legal. Safety is always the paramount concern, and <R03> clearly says that an otherwise-legal device on a robot can be disallowed if, in the judgement of the inpsectors or referees, it poses a hazard.

I would surmise as much, but I'm going to ask the question anyways. I've seen enough official interpretations counter to my instincts that I feel safer just checking.

[Richard]

Originally Posted by Brandon Holley

i think this rule is good, arms could get out of control...but then again this is FIRST :-P

Uhh, yeah. I was one of numerous volunteers to get inadvertently whacked by a tetra in 2005, while standing near the edge of the field. I recall seeing video somewhere of another volunteer actually getting capped, and something similar happened to a robot operator when an arm reached over the end wall and dropped one.

FIRST will continue searching for rules and procedures to keep us from hurting ourselves. However, none of this will substitute for judicious application of common sense.

[Brandon Holley]

Originally Posted by Richard

FIRST will continue searching for rules and procedures to keep us from hurting ourselves. However, none of this will substitute for judicious application of common sense.

without a doubt

[Pat Fairbank]

Originally Posted by Richard

The test will probably be to place the arm or extension so that it is at its maximum reach, then verify that the robot still fits within the 72" wide x 72" deep limit.

I don't think this kind of test would work. The rule states that "a ROBOT may expand up to a maximum width of 72 inches and depth of 72 inches", not that the robot must fit within such a limit at maximum extension.

If a team were to design a robot with an arm that was mechanically capable of exceeding the limit, but either programatically limited the horizontal extension of the arm or trained their operators to always stay within the limit, it wouldn't appear to be a violation of <R12>.

[Madison]

Originally Posted by Pat Fairbank

I don't think this kind of test would work. The rule states that "a ROBOT may expand up to a maximum width of 72 inches and depth of 72 inches", not that the robot must fit within such a limit at maximum extension.

If a team were to design a robot with an arm that was mechanically capable of exceeding the limit, but either programatically limited the horizontal extension of the arm or trained their operators to always stay within the limit, it wouldn't appear to be a violation of <R12>.

This sort of litmus test cannot work this season, as the rules explicitly state that robots are permitted to extended beyond this limit while in their home zone. It's entirely likely that many robots will have mechanisms that extend beyond 72", possibly even serving multiple functions, and that there's no comprehensive or accurate way of determining -- on or off the field -- whether this rule has been violated.

[jdejoannis]

Originally Posted by Kevin Sevcik

It almost certainly means anything for any amount of time. What should really get you thinking is if it only means you should be able to fit your robot inside a 72" x 72" area at all times, or if there are some sort of defined x-y axes on your robot that fix the orientation of the square.

That is to say, if you only have a pole sticking out the front of your robot, can you assume the pole is extended along a diagonal of that square and is limited to something like 90"? Or do the edges of the square have to be parallel to the sides of your robot and you're limited to 72"?

The first one is likely to be the correct reading of the rule. Imagine a referee checking the robot with a 6x6 foot frame - orienting it as needed to fit everything in. The words "length" and "width" would simply refer to arbitrarily oriented Cartesian coord axes.

[jgannon]

I've been doing a little trig, and a little Paint.

The square is the bounding box, the rectangle is the robot. The diagonal of the box is 72√2, the length of the robot is 38, and the wasted part of the diagonal in the lower left is 14. As such, I calculate that an object of negligible width can protrude (72√2)-38-14 = 49.8 inches from the front of a standard size robot. Is this consistent with our current interpretation? Does this make sense in the spirit of the rule?

[BillP]

Originally Posted by jgannon

As such, I calculate that an object of negligible width can protrude (72√2)-38-14 = 49.8 inches from the front of a standard size robot. Is this consistent with our current interpretation? Does this make sense in the spirit of the rule?

No, this is NOT within the spirit of the rule as I understand it. The robot in your drawing clearly has a length (front to back) in excess of 72 inches. However, with the current wording of the rule, it would be OK if your robot was round because the "front" of the robot would be poorly defined.

It will be interesting to see how this is handled in the updates and the Q&A. It won't be officially answered anywhere else.

(PS, Good to see ya again Joey!)

[Katusha]

That whole line was super confusing . As far as I understand we can only transform in width and length in the home zone but when we're out on the field we can go as high as we want within the restriction of the cieling. Is that what everyone else got?

[Lil' Lavery]

Originally Posted by Katusha

That whole line was super confusing . As far as I understand we can only transform in width and length in the home zone but when we're out on the field we can go as high as we want within the restriction of the cieling. Is that what everyone else got?

When in the home zone, you are allowed to expand as large as you want (provided you are still entirely in the home zone). When outside of your home zone, you may expand to a maximum of 72" "width" x 72" "depth".

[Kevin Sevcik]

I'm leaning toward jgannon's interpretation. I've already posted the question to the Q&A, so we'll see what the official word is.

I'm for jgannon's interpretation because BillP's reading means that the front and back of the robot is arbitrarily defined by someone other than the team. In that case specifically to the team's disadvantage. At the very least, the team should be able to decide which way is what. Saying that it would be okay on a round robot is just semantics and silliness. What if I have slightly bowed out plexi on all sides of my robot? There's no flat surface to attach the axes to there either.