Quote:
Originally Posted by JamesCH95
You may have 1 mechanical appendage at a time that may extend up to a 14" offset of your frame perimeter. If the robot is a circle, any appendage must remain within a circle of a 14" larger radius with the same center as the frame perimeter. If your robot is a rectangle then any appendage must remain within a rectangle of 28" greater width and 28" greater length with the same center as the frame perimeter.
The appendage may have forks or splits in it as long as it is mechanically connected in such a way as they must function unison. Your arm+hand+fingers is considered one appendage. Your two arms acting in unison through brain commands (i.e. robot code) are still two separate appendages.
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The GDC still needs to say so, and say so in a way that clears up the minor inconsistencies. This wouldn't be a bad interpretation for a team to employ (in the absence of clarity), because it's conservative and likely to stand up to scrutiny by competition officials.
But it's not helpful for FIRST officials to each be enforcing slightly different variations on the rules, because the GDC wouldn't clarify things a bit further. That's particularly problematic with the forked appendage rule: what's a valid mechanical connection? Is it literally anything—e.g. the rest of the robot? Is it anything that bears a load of more than a certain amount? Is it anything that looks structural? Is it an issue of degrees of freedom between appendages? Or would a thread tied around two appendages make them one? What if the thread was instead a coathanger? What if it was a tie rod with ball joints at each end?
When inspectors/referees are making rulings, hopefully they're also considering the general case—because what seems good in specific circumstances may have implications for future rulings (if they're consciously attempting to be consistent, which they usually are).
Quote:
Originally Posted by RRLedford
While this rule may well be intended to mean "beyond ONLY a MAXIMUM of ONE SINGLE EDGE," it is not really worded to accomplish this.
Plus, it should have added ==> "and may NOT extend ANY AMOUNT beyond ANY OTHER EDGES of the robot." -- if this was what they really meant.
Consider this example: Let's suppose I tell you to deploy an appendage diagonally at 45 degrees off the corner of our bot for 14" of extension, and the robot is a rectangle.
I then tell you to check whether this arm extends more than 14" beyond any single edge of the robot.
You then report back to me that compared to NO SINGLE EDGE does the robot arm extend more then 14". You verified this by holding up a long straight edge spaced 14" away from each side, one at a time, to confirm this.
This rule's wording can also simply mean that you are comparing the tip of the arm's position to EACH INDIVIDUAL FRAME EDGE LINE ==> ONE LINE AT A TIME. So even though the appendage clearly extends beyond two of the four edges, it does NOT extend beyond 14" for "any single edge " measured ALONE.
BTW, if a circular robot is allowed, does it only have one edge? If so could it deploy a skirt outward, all the way around the robot for up to 14" as long as the skirt formed a "contiguous" loop?
There does seem to be a distinct bias toward rectilinear design concepts with the structure of the FIRST game rules.
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I'm not sure I'm totally on board with the one-edge-at-a-time measurement scheme, because I would tend to assume the rule is to be interpreted simultaneously with respect to all edges—but I concur that it's not clear whether the appendage has to physically cross the projection of an edge, or simply be extended into the space beyond an edge. (Imagine a piece that crosses only one side, but then is actuated so it curves into the space beside another edge. Was it "extend[ed]...up to 14 in. beyond a single edge"?)
As for the rest, you beat me to posting it. FIRST has a history of issuing interpretations that don't make sense with respect to non-rectilinear robots. And they frequently omit things like maxima and minima (or any tolerancing at all).