Measuring height of robot when robot rocks due to drop center drivetrain

Is there a rule about measuring a robot when it rocks due to a drop center wheel? 2 years ago the rocking caused our robot to go 1/8" over height when rocked back, but it normally rocked forward due to the COG. It passed inspection when they shimmed the back wheels but we wondered if that was legal. Have been unable to find it in the rules.
They are very aware they should not build to the limits, we’re just wondering if there is a rule.

I think the general consensus is don’t build to the limit


Edit: Look at Jon’s comment.

The rule is it can’t be over the height during the match, so if it were to rock and be over the height while driving, it would not be compliant.

This is different to years that had a starting configuration height, as all that would need to be compliant is the height at the very beginning of the match, which I assume is why you passed 2 years ago.

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I’m not so sure about that…

When discussing height, there are two rules to consider this year. Like most years, R3 defines the STARTING CONFIGURATION:

R3. A ROBOT’S STARTING CONFIGURATION may not have a FRAME PERIMETER greater than 120 in. (~304 cm) and may not be more than 45 in. (~114 cm) tall.

With that rule, it’s all about how the robot sits when you put it on the field - rocking is not an issue.

G17. Tall ROBOTS not allowed. ROBOT height, as measured when it’s resting normally on a flat floor, may not exceed 45 in. (~114 cm) above the carpet during the MATCH, with the exception of ROBOTS intersecting their ALLIANCE’S RENDEZVOUS POINT during the ENDGAME.

The key here is the phrase “resting normally on a flat floor”. Is a robot that’s moving “resting”? It’s easy to say that a robot that rocks above 45" might not be legal… but what about extreme rocking (aka popping a wheelie)?

In order to be able to have a consistent measurement, you need a consistent frame of reference. You need to be able to draw a line on the robot and say “it doesn’t matter what the robot’s doing, we’re going to consider this line to be perfectly vertical”, and then do your measurement in that direction. The best way to do that (and the way the rules indicate), is to “draw that line” when the robot is resting normally on a flat, horizontal surface.


Looks like I didn’t remember the “resting” part of the rule. Really highlights the importance of checking the rules before making a critical decision.

I don’t want to confuse anyone. The rule specifies a height that the robot cannot exceed.
R3. A ROBOT’S STARTING CONFIGURATION may not have a FRAME PERIMETER greater than 120 in. (~304 cm) and may not be more than 45 in. (~114 cm) tall.
If the robot rocks by itself and can move on the field after you place it there, it cannot be higher than 45".


How would a ROBOT with a drop center 6 wheel drive be judged that due to CoG have a resting position that is just under 45", but if rocked the other way be over. When placed on the field its CoG would keep it rocked to a legal height.

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