Flag holder position

Update #4 just published talks about the flag holder in one of it’s sections. As a Championships Inspector, I just want to remind every team that whether or not their robot is 51 inches high, their flag holder has to be.

“<R17> Robots must use one of the two FLAGS provided at the event queuing location to display their ALLIANCE color (red or blue). The FLAG shall be held in a flag holder mounted on their ROBOT. The only acceptable flag holder is a 12 inch long piece of 1/2” (nominal) Schedule 40 PVC tube. The tube must be a single, continguous piece, capped with a commercial PVC cap cemented at the bottom end. The tube must not have any “lightening holes” or other modification other than mounting holes, paint, or other decorative finishes. The flag holder must be permanently mounted to the ROBOT such that when the ROBOT is in PLAYING CONFIGURATION and the top of the FLAG is 75 inches above the floor. As the flag pole is approximately 36 inches long, that means the top of the flag holder must be 51 inches above the floor. The region above the flag holder must be kept open and clear of obstructions so that the FLAG can be placed in the holder and displayed during the MATCH and the LAP INDICATOR is visible to the Lap Detectors (see Rule <R18>). The intent of this rule is to insure that the FLAG is as high as possible so that it may be easily seen from any side during the entire MATCH play, while fitting under the OVERPASS as the ROBOT drives around the TRACK."
(bolding mine)

Now, how many tasm forgot to design a place for their flag holder?

This is possibly the worst-thought out rule in ‘08. I agree with he intent, but I am forced to wonder if the GDC considered what happens when a 40" ball falls onto the robot from 7’. Usually the top of the flag pole will be the highest point since the maximum starting size is only 60". I also wonder if they considered what happens when a flag pole at 75" drives full-speed forward under a trackball that hangs down to below the 75" mark in hybrid mode – it’s either a flung flag or a broken flagpole.

I forsee either alot of popped trackballs or alot of broken flagpoles.

Don’t forgot about possibly losing your lap counter since it is attached to the flag pole.

I’m not sure it will be so bad. The diameter of the ball is actually a benefit to damage mitigation when it falls from the sky. Since the mass is about 7.5 lbs, the force of collision will be spread out over a larger area compared to, say, a bowling ball size. The flags will supposedly be held in place with a rubber plug, so if the flag contacts field elements, hopefully it will remain in place. If it doesn’t then your laps won’t get counted. Our team, for one, is taking design steps to ensure that the flag doesn’t get flung out of it’s holder. In years past, some teams designed with the hope that game play would get rid of the hindrance, but this year that strategy will be detrimental.

This is what I think will be the problem. In years past we always saw flags flying off the robots. This year if they are held in place and cant fly off, they may break. Hopefully they have lots of extras.

Don’t forget that the 75" top height is a rule, not a suggestion, and that all teams must provide PWM connection near the flag holder in which to plug the lap counter device. For teams that are using a kitbot or low height chassis, you will be required to have the flag holder attached such that it meets the current rule. Please plan for it now.

Yes, as Al says, it is a rule so build accordingly. Keep in mind that the flag poles are very flexible. I would be impressed if they broke without being mechanically caught in something. They will certainly survive impacts with the ball. The weak link will be how teams implement the flag holder. Protect the lap counter and associated wiring, allow it to always be clear from above, and don’t let flag impacts dislodge the flag.

I brought this up early on in this post. The flag forced us into a design that I think will be 1 of 3 types. I just modeled in the flag on our robot this year, and that sucker is huge! In fact, I’ll say right now, that our flag (even though we tried not to) will get beat up. But hey, it’s a 40" ball…

For the inspection checklist, which is available along with the other documents, it’s worth noting that it says 75±5" for flag height.

Just remember that the rule, not the inspection sheet, is the ultimate authority. And the current inspection sheet is still in draft, not final, form.



what should be classified as “clear” above the flag/flag holder? is it directly above or around the flag within “x” inches?

what should be classified as “clear” above the flag/flag holder? is it directly above or around the flag within “x” inches?

This also seems like it could create problems with fast robots and a mast at 56" turning and tipping over easily

Directly above for sure. The detector is right under the overpass.

And according to <R18>,

<R18> ROBOTS must use the LAP INDICATOR provided by the field personnel during all official tournament MATCHES. The LAP INDICATOR is attached to the stopper on the flag pole. When the FLAG is placed in the flag holder, the stopper will insert into the top of the holder. To accommodate the LAP INDICATOR, the area within a minimum 180—degree horizontal arc around the top of the flag holder must be kept clear of any obstructions within a 2-inch radius. This region must be kept uncovered and visible from above. To ensure that every FINISH LINE CROSSING is properly recorded, the LAP INDICATOR must be visible to the Lap Detectors when the ROBOT passes under the OVERPASS…]
(emphasis mine)

Thoroughly reading the rules multiple times is a definite advantage.

Looks like it ended up being important enough that it’s now changed to ±1 inch.