Scaling and G18 Interaction

Q. G18 penalizes an extension more than 15" beyond the robot’s frame perimeter. Is plane the measurement occurs in relative to the robot or the field? For instance, a robot uses a grappling hook to climb and tilts 90 degrees as it winches itself up. Do you do the same “virtually transposing the robot to a flat floor” as with R22 to determine if the hook extends greater than 15"?

A. Extensions outside the FRAME PERIMETER are measured in the same plane as the FRAME PERIMETER. As the FRAME PERIMETER is re-oriented (e.g. when a ROBOT drives up the BATTER), the plane of measurement is similarly re-oriented.

So if I am understanding this correctly when a “tape measure scaler” gets reoriented it will be in violation of G18. Does this shut down that style of climbing?

Does anyone have other ideas for getting a low bot to scale? It seems like any method would require being able to keep its orientation parallel or nearly so with the ground.

you just have to not tilt while climbing, keeping your bumpers parallel to the ground.
i guess we’ll see deployable arms as well, but i feel like tape mesure scalers will be the most common for low bots



So as several people have mentioned I was interested in exploring the “just.”

The first idea that comes to mind is moving the “tape meausre” inward towards the tower and then using an arm with a roller on the end to create a second contact point against the tower. That would allow the robot to roll up the side of the tower while maintaining a flat orientation.

Other thoughts or ideas?

And then the roller could double as making it easier to get over obstacles not a bad idea.

I find this really interesting, and perhaps a follow up Q&A is important/necessary. I agree with the interpretation of the answer as applied in this thread, but wonder the following: most tape measure bots will be <13" in height. Tipped upright, and calling the “base” the frame perimeter, will result in a frame perimeter < 120," and a height likely under 4’6" – if a robot started a match upright, and tipped over, this would probably violate the 15" beyond the frame perimeter rule (though there might be ways of doing it that don’t. Then again, said robot would still have to follow bumper rules. (Maybe this is why this rule is what it is). Still, I wonder whether a team could inspect a robot with different sides as height (there haven’t in the past been rules that define the wheel base as the bottom, just common sense). It’s interesting that, as long as other frame perimeter rules are filled, we can’t tip upright, and have that position count as a new, but legal, orientation. Just some thoughts.

Where are you thinking of the tape measure in this scenario? Putting it right against the tower probably wouldn’t work. Putting it a few inches farther from the tower than the CoM should work, though. If you have a roller higher than the CoM, the force from the roller should provide a balancing torque to keep everything from flipping over. Definitely need to Free Body Diagram it to make sure everything balances, though.

My prior thought was a three point lift, which would guarantee levelness, at the price of much more complication. I like your idea a lot better since we’ll likely have something over the bumper for boulder grabbing and defense manipulation anyways.

I assume you mean that the stabilizing arm extends downwards, and that the “tape measure” is just a bit closer to the tower than the robot’s CG? The stabilizing arm would need be limited in length, then, or else the bumper height rule would be violated.

The only other idea I’ve got is to move the “tape measure” a bit further away from the tower than the robot’s CG, and extend the stabilizing arm *upward *from the tower-facing edge of the bot. This would allow a longer stabilizing arm, and therefore greater stability.

Either way, though, you’ll still need the “tape measure” anchor point to be pretty close to the bot’s CG. As if it wasn’t hard enough already to package all these systems in a low bot…

Won’t work. Robot has to start inside the frame perimeter, so your bumpers would be below your wheels, unless the wheels dropped down. And the bumpers have to stay within the bumper zone of 4"-12", so you’d have to fit all this in a space approximately 3" wide. (Bumpers are atleast 2.5" thick, so you’re less 5" of space.)

I’m not 100% sure Q504 means the robot has to remain horizontal during climbing. Sure there’s a 15" extension in the plane of the bumpers rule, but there’s also G17 which says the robot can be as tall as necessary in the last 20s. If the latter overrides the former, than you could tilt vertical while extending up.

Even if both rules apply at once, you might be able to time the rotation angle (RA) and extension length (EL) so that the projection in the plane of the bumpers (EL*sin(RA)) never exceeds 15" outside the frame perimeter (EL has to shrink as RA grows). That’s going to be a nightmare to enforce though.

Thinking about this a bit, the wall of the castle is going to interfere since it will push your frame perimeter towards your extension (the rung is only a few inches from the wall). So if you were going to rotate while climbing, you need to tilt wall-side down. That said, you could tilt down at least ~20 degrees (at the base of the tower) before the frame perimeter rule cuts below any extension reaching for the rung. Don’t tilt back though!

The GDC has already noted elsewhere that the 54" height is robot relative, so as tall as necessary is probably oriented the same way and perpendicular to the extension direction.

Not tipping backwards is the tricky bit for a low bot with a tape measure lift.

Height is always measured perpendicular to the FRAME PERIMETER as if the ROBOT were sitting on a level floor. See the picture in the manual where the ROBOT is tipping as it goes over a DEFENSE. So there’s no question of whether G17 or G18 has precedence - they both apply at all times (with the obvious exception during the endgame).