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Clarification needed on SG2: horizontal relative to what plane?


4028X
2-Jun-2023

According to SG2 <SG2>, it's clear that "Robots may not expand horizontally beyond the 11” x 20” starting dimension limit at any time during a Match."

Could we get clarification on "horizontally"? We believe there's two reasonable interpretations:

(A) Horizontal relative to the plane of the field, or (B) Horizontal relative to the plane of the robot's starting footprint

If it's relative to the field plane (A), that means that a bot that starts off 11x20x15 and then tilts at, say, 20 degrees to get up and over the SZ bar to fully park will be in violation of SG2 for the duration of the maneuver. Another way to think of this is that the projection of the bot onto the horizontal field plane exceeds 11x20. This has the implication that a 11x20x15 bot must take special measures to avoid ever exceeding the volumetric footprint of 11x20, right? Many bot designs that attempt to drive up and over the bar will likely fail this test, unless the bot is small or short and be careful if carrying a pile of blocks. Refs must also carefully watch for these "expansions via tilting" - which will be difficult to adjudicate fairly since the bots will presumably be in motion. The ref would have to eyeball whether the bot "expanded" via tilting; I'd expect many disagreements could arise over bad calls. Alternatively or additionally, inspectors would have to ask teams if the bot tilts at any time, and if so, measure the projection of the bot onto the field. This whole thing seems messy.

Personally, I'd advocate for interpretation (B). It's clean, easy to inspect for, and gives teams the latitude to come up with ways to go over the bar without having to worry about violating SG2.

Unless that's the intention - to challenge teams with this. But if that's the intention (which is fine!) please don't make it a subtle gotcha. Please state clearly that this is something teams must consider in bot design.

Thank you.

Answered by committee
9-Jun-2023

(A) Horizontal relative to the plane of the field, or (B) Horizontal relative to the plane of the robot's starting footprint

Your interpretation "B" is correct.