# G17 Algorithm

BALL Return Timing - BALLS must be returned to the FIELD within a specified period of time to prevent delaying the game according to the following algorithm:
Texpire = Tscore
• where T - [11 + (4 * n)]
expire
• T, is the match time, in seconds, assigned to each individual BALL, at which point the Field Management System automatically assigns a PENALTY if a BALL is not passed through the BALL RETURN COUNTER,
score
• n is the number of balls that have passed through either BALL COUNTER of the ALLIANCE, but not yet passed through the BALL RETURN COUNTER. is the remaining match time, in seconds, on the match timer when the ball enters the BALL COUNTER, and

If your alliance is in the possession of a ball with 15 seconds or less left, you have 0 seconds to place it on the ball return, thus incurring a penalty. At this point, it seems that your team should try putting balls in your opponents goal, giving them penalties. Is this a viable strategy?

No you have until the clock reads 0 to get the ball back on the field. You are solving for the time on the clock, not the time you have to move the ball.

Incorrect.

T expire (x) = T now – { 11 + (4 * # unexpired balls currently in Station) }

T expire is the time at which the penalty is applied.

So, you put a ball in at 15 seconds left. Texpire = Tnow-{11+4*unexpired)}

Tnow is 15. We will assume an empty alliance station (unexpired = 0).

Texpire = 15-(11+4*0)=15-11=4.

They have until the timer reads 4 seconds left to put the ball back out.

For reference, the DOGMA document on the FRC website will help understand the algorithm. It is at http://usfirst.org/uploadedFiles/Community/FRC/Game_and_Season__Info/2010_Assets/DOGMA.pdf

So the unexpired balls is any balls in the station prior to the incoming ball?
In this case, the unexpired balls would be 0, because you are assuming that there aren’t any balls in the station until the ball rolls into the station.

Exactly.

What happens if a ball is scored at 1 second? Is there some point were the system stops? I’m guessing that any ball scored after 11 seconds wouldn’t need to be put back into play. Please don’t show me any formulas, i’m just a dumb parent that can’t figure this out.

no. Once you get down to 11 seconds you would have until 0 secs to get the ball back… and once 0 seconds is hit, you cannot receive a penalty. Therefore, the ball doesn’t have to be returned.

That’s a logical conclusion, but it should be verified with Q&A.

Ok, but this is getting pretty annoying. It seems like there’s about 5 threads all about G17. PLEASE look at other threads before starting a new one and add on to the other if it’s related.