Ball Shooter

One of the subsystems I lead was the design of the ball shooter. This subsystem consisted of a spinning wheel powered by some BLDCs to achieve high enough RPM to fire a shot from over 20 feet away.

Initial Prototyping/Design Phase

I started the design process by doing some rough kinematics to determine the initial velocity of the ball we needed to hit. Using that data and the diameter of the wheel we determined the RPM and gearing of the shooter. A rough prototype was set up in a classroom and we played around with RPM, gearing, and wheel type.

Intermediate Versions

One problem that needed to be solved was how we were gonna make the backplate for the shooter in such a way that allowed us to test different ball compressions and hood angles. The solution I came up with was to machine slots 30 thou wide into the sideplates. Then we slid some thin sheet metal into these grooves and jammed o-rings into the gaps so it wouldnt slide anywhere. This ended up working really well.

Later Versions

The biggest difference between these versions is in the later prototypes I designed the motors/gearbox to be in the front of the hood instead of behind it. This allowed us to use larger 6” wheels rather than the 4” ones from previous versions. It also meant that the motors were centered about the rotation of the turret, which is optimal for reducing moment of inertia. Additionally, this design was overall lighter in weight when just considering the new frame.