How is 54" size limit being inspected?

We aren’t competing until the 4th week ( and the 5th and the 6th)
Can anyone enlighten me as to how a team needs to confirm that they meet the 54" rule?

Are inspectors asking this question? Are they asking a team to expand to its full size and measuring…??

just wondering.
We have a CAD drawing that shows our extensions to give an inspector to show how we meet the rule.


We printed off a few cad models to prove that we didn’t exceed 54". The inspector said he appreciated this. To manually check, he took a measuring tape, and measured from furthest point to furthest point.

At Northern Lights we had to declare our maximum extensions so that they could make the refs aware. It might have been measured because the person with the exact answer was not there but the way the conversation was going it might not have been measured if the answer was confident (the parts were extended, though). I am guessing if the number given did not sound realistic a measuring would have happened anyway.

In Portland, the inspectors had a 54" circle taped on the floor. The robot was placed in the circle. Any mechanisms or appendages were extended to ensure that the 54" cylinder wasn’t breached. They also used a square made of wood and placed it at the edge of the circle to see if anything above the floor broke the cylindrical barrier.

I ask teams to extend any components that go outside the frame perimeter then pull out a measuring tape.

Same thing happened at our inspection, but that doesn’t measure a true 54" diameter in most cases.

This is not the correct way to check. Our robot (see signature) is very close to being over the 54" limit, I think we were within about 1/2 an inch. The maximum point method will pass illegal robots. See the below picture for an explanation:

At Fingerlakes, after an Inspector tried this method, we informed him why it was wrong and they pulled out a prinout of a 54" circle, which they projected upwards with an ruler. This seems like the correct method to use.

Agreed, that makes much more sense. We never got pulled to the printout at Finger Lakes though. I was surprised that this wasn’t standardized between different regional, but how can the cylinder not be measured the same way within a regional?

The point to point method will still work if the inspector measures from the bumper corner to the mechanism corner (at least for most cases), but I could see this being missed. EDIT: doh, math. No it wont.

I was looking forward to seeing a cylindrical sizing box this year, but given the quality of sizing boxes in the past, I probably would have hated it. :rolleyes:

As I understand it, the measuring tape was supposed to be used to get a rough idea of whether they were at risk of breaking the cylinder. They subtracted a portion from the 54" to account for the circular nature of the cylinder and measured that. If you were close, you’d get pulled to the real circle for a closer inspection.

We were right on the verge as shown in our CAD, we were within 1/2" of 54". We clearly told the inspector this, which is why I’m confused.

We’re certainly supposed to be asking this; it’s a specific item in the inspection checklist. If this doesn’t come up during your inspection ask the inspector why not.

At Hub City, afaik we only had one robot that had any possibility of an issue with this. I happened to be the inspector; by mutual request (team and the inspectors) we went through a reasonably exhaustive series of measurements to determine that there was no problem. We didn’t have any kind of circle drawn to do this, but a tape measure and a little math did the trick.

Ask me tomorrow about GKC. At early check-in tonight I didn’t see any robots that might have a problem with this sizing but I wasn’t particularly looking for it, either.

What we can be sure of is that if any two points on the robot are more than 54" apart then they violate the rule.

There are also many machines that clearly are not in violation of the rule.

That leaves some “borderline” machines, but likely not many. It might be easiest to tape off a 54" circle, tangent to a wall, extend the appendage to touch the wall, and then place the robot inside the circle.

Just so long as we don’t have that silly hoop back again. What year was it that we had the big hula hoop?


Unless they’re not in a plane perpendicular to the axis of the cylinder…

In Portland there was a circle taped on the ground to set the robot in. Then a vertical board was run around the circle to make sure that no part of the robot extended out of the circle. I think they will use the same technique in ellensburg.

At Lake Superior, there were only a couple robots that warranted measuring - the others were all clearly within the limit. All but one of those measured didn’t need any further looking, they clearly had more than an inch to spare with just some quick “napkin math”. The other however was close enough that I felt the need to go further… I did a quick (less than 10 mins) CAD mockup with all the inportant critical dimensions to check it out.

I’m just trying to get in an inspector’s head, but if a team provided you with a CAD printout, would you have done your quick CAD anyway?

If the critical dimensions (length/width of each part, measurements of diagonals) were included on the printout by the CAD software and it was clear that everything fit within the cylinder on the printout, then no, I wouldn’t have done my own CAD. I would have verified those critical measurements, however, to ensure that the CAD model was a valid representation of the robot in its maximum playing configuration… often what we design on the computer doesn’t exactly match what’s built!

At our district event the inspectors used a 54" ID polycarbonate circle. The circle was halved and could be oriented in any direction, I assumed FIRST supplied it.

They used it and even told an inside climbing team they would be penalized if they started outside the pyramid (their climbing mechanism deflected when they went under). They played the elimination matches never leaving the inside of a pyramid.

Does the 54" cylinder include bumpers?

I was trying to determine this by reading the rules. G23 says the ROBOT must fit within the 54" cylinder.

The definition of ROBOT does not mention bumpers.

The definition of BUMPERS says they attach to the ROBOT.

That would make me think that BUMPERS are separate from the ROBOT and not included in the 54" cylinder for inspection.