Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Just in case anyone is interested, if you want to convert the GetRate output to RPM, do the following simple thing:

In Begin.vi where you OPEN your encoder, in the DistancePerCount input, wire in 60 / (EncoderCountsPerRev).

For example, if you are using a 32 count per revolution encoder, wire 1.875 (60/32 = 1.875) into the DistancePerCount input. Now you have RPM.

(The WPI detailed help lies - you don't get Hz from GetRate. Actually, you do get Hz if you don't wire anything into DistancePerCount.)

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Well, our RPM values are all wrong, then... but it doesn't matter, because we've calibrated ranges using raw encoder values. We don't care about units as long as it works!

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

I was wondering how you were launching at .25 RPS :P

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Methinks perhaps you misunderstood either way. Our shooter PID is accurate to within +/- .25 rps... It's difficult to launch balls at that speed!

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

It was a science fair project....and it took Grand Prize :eek: so I guess we'll keep the feedback system on our robot

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Well send him my congratulations !!!

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

pfreivald what pid are you using? Is it a canned one or all your own development? What are you using for RPM sensing?
Thanks
Bruce

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Well, the whole thing abruptly stopped working this morning -- some weird electrical short. Last night on the practice field it was pretty darn consistent! :eek:

We were using the default LabView PID, with the kit/AndyMark encoders for feedback.

Re: Problems with tuning shooters using AM basketballs on Practice Field?
 

Just returned from my first competition. What a rush! Wanted to offer a few other points that I haven't caught mentioned in this thread:

1) Many teams have similar shooter designs. They all have some minimum spin up time before they can expect to deliver a good shot. Many then delay second shot for shooter to come back up to speed. This can kill your hybrid mode!! Watch some of the game videos... all three alliancemates fire off their first shot at the same time. The missed shots bouncing off are deflecting what might have been good shots.
1a) We put a toggle switch right on the driver station for whether or not we want a 4 second delay before shooting in autonomous mode. I think the only match where we did not use it, it was because none of our alliancemates had any hybrid shooting capabilities.
1b) Show up to the competition knowing as exactly as possible what time your balls are going to be shot so you can coordinate with alliancemates.

2) If you make it to the elimination rounds, they restock the field with ALL new balls! If your shooting in your last match went great, you're going to be sending them out of the field if you don't make an adjustment and are not a dumper or a catapult.
We were fortunate in two ways on this point. Firstly, we had a student that thought to ask if the balls would be changed. Secondly, we had easily adjustable RPM for shooting.