Ball Shooter
An adjustable ball-shooting prototype.

Purpose:

  • To explore shooter design concepts in FRC.
  • To develop an adjustable shooter prototype that can be modified for different game pieces.

V1: Double Shaft Configuration

6032 Adjustable Shooter Prototype - Double Flywheel Configuration

Design Notes:

  • 80/20 structure is rigid and adjustable.
  • Bearings and motors mounted to frame with 3D printed brackets (modified HYPEBlocks).
  • Large Colson wheels (4" x 2") will hopefully provide grip and sufficient angular momentum. Wheels can be easily swapped out.
  • Falcon 500's with a CIM Mount, 1:1 VersaPlanetary
    • 1/2" Hex VP output with shaft coupler (shown)
    Or
    • VP Universal Female Output with female 1/2" Hex adapter
  • Adjust wheel speed with servo testers. Slower on top and faster on bottom should increase the angle of release and give it some backspin.
  • Consider adding side guards and a feeder ramp (wood, lexan, cardboard, ...) for safety and so balls are fed in a consistent manner.
  • This could be modified as a hooded shooter, and modified for different sized game pieces.
  • Access the Onshape document for more details.
Sketch & Cut List

3/23/2021

  • When mounting anything to a Falcon 500 motor, you need to use very short screws. 0.5" is too long because it will bind with the motor internally.
    • Use #10-32 SHCS, 0.375" long to mount a CIM adapter to a Falcon.

3/24/2021

  • Proof of concept
  • Next steps:
    • Adjust wheel speeds to "dial in" on a target and evaluate consistency.
    • Consider adding flywheels to shafts, see if that impacts consistency & range.

3/26/2021

We added brass flywheels
  • The flywheels gave us a more consistent shot when sending many balls in succession.
  • Students adjusted shaft speeds to aim for a specific point on the wall. They started with slow shaft speeds and increased the speed of each motor one at a time, dialing in on the target.
  • Next Steps:
    • Integrate this mechanism onto a robot.
    • Work on ball intake.
    • Work on ball storage & how to feed them into the shooter.

4/15/2021

  • Integrated the Shooter onto a prototype robot.
  • Feeder mechanism supplies balls to the shooter wheels.
    • Already have some backspin before entering the shooter - this is good.
  • Next Steps:
    • Continue to "work backwards" & think about how balls can be fed into the feeder mechanism. Maybe from the front of the robot, or maybe behind the wheels.

V2: Hooded Configuration

6032 Adjustable Shooter Prototype - Hooded Shooter Configuration

Design Notes:

  • Similar to the Double Flywheel version above, modified by removing one shaft and replacing it with a hood.
  • May need to use second motor and/or speed it up with a belt & pulleys.
  • Insert dowel rods in holes or use long standoffs/churro/thunderhex. Fasten a flexible polycarbonate sheet to the dowel rods to create a smooth hood.
  • Adjust compression and release angle by using different holes for the dowel rods.

Inspiration

Team 5013 Trobots

This shooter uses two sets of wheels. You can control release angle by adjusting the speed of the top and bottom wheels.

Ri3D Team 1.0

Here is a prototype version of a similar idea to team 5013.

3847 Spectrum

This concept is made with Protopipe.
From the Spectrum Protopipe documentation

2706

This design features a simple over the bumper intake, low profile, and shooter with a non-adjustable hood.

5712 Gray Matter Robotics

1690 Orbit

This team was able to adjust the angle of their entire shooter in order to adjust the release angle.

6328 Littleton Robotics

Team 6328 has an amazing shooter, with full CAD available in Onshape. We can learn a lot from these details in CAD.