DEWBOT XIII Shooter

It had been the team's intention and strategy for DEWBOT XIII to be a high-performance shooter (together with good rear running capabilities and a fast, reliable climb). Alas, we did not accomplish the critical shooting goal. Our shooter was definitely middling. While very consistent in its shooting and capable of shooting consistently at up to 6 balls/s, feed issues limited us to an average 2.5 balls/s. In addition, while shooter elevation and wheel speed are adjustable,we had a limited number of pre-set shooting solutions and limited objective data on which to base such solutions.

The Shooter System comprises several interacting components:

Shooter
Feeder
Ball Pickup
Hopper

Shooter

The shooter is a basic single-wheel shooter. While simple, this mechanism went through an enormous amount of testing and development, including multiple prototypes, the last few being CNC-produced.

Some key learnings:

A flywheel reduces the magnitude of speed reduction while shooting, but not recovery time
More power reduces speed recovery time
Holes in balls (fuel) interacting randomly with thin shooter rails randomly throw off ball trajectory
6 inch wheels provide more consistency than 4 inch
2 inch wide wheels provide more consistency than 1 inch wide
Printed guides expanding the ball contact area from narrow rails to >1/3^rd circumference, thereby improving shooting consistency

Key design features:

PID controlled wheel speed
3:1 reduction via 1-stage versaplanetary gearbox
Up to (3) 775 Pro drive motors
Adjustable shooting trajectory 60-85° from horizontal - adjustment via a quarter scale (large) servo. The servo drives a 14T gear (20 DP - 14° contact angle) which drives an 84T half gear on the trajectory hood. A 180° rotation of the servo rotates the trajectory hood by 30°.
Trajectory hood rotates co-axially with shooter wheel axle.

As of FRC Championship, we seem to have a shooter capable of shooting ~6 balls/s with good accuracy. We, however, are not able to feed this shooter consistently at this rate. As a result, shooting rate is erratic.