# Frame Perimeter when climbing tower?

Hello all,
In regards to the frame perimeter, my team was planning on using a pneumatic cylinder to lift ourselves at the end of the match. The plan is to ascend and then essentially curl the front of our robot upward 90 degrees. However, while hanging, this would put our pneumatic arm over the 15 inch limit for the Frame Perimeter extension. Would this be considered a violation? Or because it is the last 20 seconds of the match would we be okay?

From Official Q & A:

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.

Thanks and ouch,

So just to clarify, this means that a robot scaling the tower with its wheels touching the tower wall would have a scaling mechanism that becomes illegal? (Greater than 15 inches)

Correct

This rule is going to be crazy hard to enforce (like the 2013 cylinder rule). Good luck to the referees!

An interesting observation, relevant to many more varieties of climbers:

Consider a robot positioned on the batter at the base of the tower, which has a mechanism that reaches up to grab the rung.

The batter is, according to the game manual, 6’’ tall and 4’ deep.

This means that the angle between the batter and the ground is arctan(.5/4).

Accordingly, the angle between the face of the tower and the plane of the robot’s frame perimeter, as defined in this rule clarification, is also arctan(.5/4).

The rung is 5’10’’ above the top of the batter. A simple calculation:

5’10’’ * sin(arctan(.5/4)) = ~8.7’’

So, were the frame perimeter flush against the face of the tower, the face of the tower would be 8.7’’ outside of the frame perimeter at the height of the rung.

Adding in reasonable bumper thickness, we end up rather close to the 15’’ limit. So, if you have a climber that follows the face of the tower up to grab the rung (as we are planning to do), you are safe within this new ruling, but only just. Be cautious of this.

It seems like this rule makes hanging unnecessarily difficult. Teams are going to have a hard enough time hanging in any orientation.

Wow. Not only do we have to hang but we have to hang while mantaining bumpers that a te relitively perpendicular to the hanging mechanism? Well I am out. Not worth it. The rules out 99% of hanging solutions that use a cable or rotation enable devices. \$5 says that they will changes this in a rule update, due to the the intention of the task. Of course I am not the GDC so I am just speculating.

Note: I understand that the rule is possible to change.

I showed my teammate this thread and tried to explain it to them and they couldn’t really understand what rule you guys were exactly debating so I made crappy cartoon diagram in MS paint that might be useful if you’re ever debating with a teammate about this rule for whatever reason.

(I don’t think the rule is super dumb. I don’t think any rules are dumb, rules are rules. I just put that last bit in there for laughs by my team)

I like this rule. It’s just like climbing in 2013, the cylinder made it tough, then they made that cylinder move with the robot and it got a lot easier. This time the perimeter moving with the robot actually makes it harder. Remember, this is an engineering challenge. If scaling were easy, everyone would do it and nobody would be impressed. But now, it is just complicated enough that you can’t just toss a hook up there and winch yourself up. Good work GDC, good work.

To the OP, what combo of cylinders were you planning to use to curl yourself 90 degrees?

Here is a quick sketch in CREO showing the minimum distace outside the frame perimeter required to reach the rung. I allowed 3 1/2" for bumpers. The hook must protrude at least 10 inches from the frame perimeter to grab the bar. That gives you a five inch margin.

https://plus.google.com/117322302265076381504/posts/aGrqUdk87dU

Just to be clear, this is assuming a 36" long robot. If your robot has a shorter wheel base (Which I assume many will), there’s more of your robot on the batter and the worse your angle gets. I used 2.5" for my sketch for bumpers for some reason so if you bump my sketch out another inch on the bottom the tolerances are razor thin. Impossible for refs to judge. Terrible Q & A ruling IMO.

The length of the robot makes no difference. You also do not need to touch the wall of the tower as in your sketch, just reach over the rung.

The rung you are grabbing onto is not flush with the tower walll. It sticks out, everyone should be well with in the 15 in limit when grabbing the rung. Now how you pull up your robot to stay with in the rules is another matter.

In practice the Frame Perimeter rule is more enforced by RI’s than the Ref’s. The Ref’s are not about to take out a tape measure and walk onto the field during play. The RI’s will check for maximum extension during the inspection process. They will look at the robot as it is sitting on the ground.

Not really. Just because an appendage CAN extend beyond 15" doesn’t mean that it** WILL**.

Correct.

Many Head Refs ask the LRI to provide a list of robots (based on inspection) that are mechanically capable of extending beyond what the game rules allow, so that refs can be advised to watch at critical moments when one of those robots is playing.

Whether the robot actually does extend too far during a match is a call for ref to make. If a ref sees it happen, the infraction should be called.

Yes! This is why it is “The Hardest Fun You Can Have”. If it was so easy that everyone can climb to the top of the pyramid in 6~7 seconds like 254 did in 2014, how inspirational would any of this be?

Quite a few people posting on this thread have indicated that it should not be necessary to extend more than 15" beyond the frame perimeter to scale the tower. If a team verifies for themselves that this is true and has a mechanism that can extend beyond the 15" limit, it might be a good idea for them to add a mechanical limit. It is usually a good idea to “just not attract the attention of the Authorities” in the first place.

Not sure why you think that. The sketch below demonstrates the longer your wheel base is, the easier it will be to stay within the 15" rule while attempting to scale.