paper: Shooter Wheel Speed Control

[Tom Line]

We've settled on PID because we simply can't get the bang-bang method to give us better results. The real issue that I think I've hit is mechanical - we're at the limits of what our system can provide. No matter how we play with gains, filtering, etc, we're struggling to get the shooter more than +/- 40 to 60 rpm (actual RPM, not filtered much at all other than to remove big spikes that are obvious errors).

Filtering the speed before our 'enable shooting' vi really doesn't help shooter run any more consistently - it just makes it easier for us to check the limits.

I did put a 4 sample moving average in to filter the pid input. That helped with some of the oscillation. We also turned down our proportional gain (we wrote a velocity PID, we're not using the position PID) to help some of the oscillation. The shooter still spins up in around 2 seconds, but that helped the oscillation as well.

I had hoped to manage a major improvement before nationals. We've improved our velocity control probably 50%, but other folks are reporting numbers that are still close to 100% better than ours. That means that in real time ball shooting, we're seeing something like +/- 1 foot in height when hitting the backboard.