FRC971 Spartan Robotics 2016 Release Video

[AustinSchuh]

Originally Posted by mr.roboto2826

How did you guys go about the development of your 2 (side by side) wheeled shooter? From the outside looking in it looks fairly simple, but I would assume hours of tweaking went into it. Could you enlighten us as to how the shooter went through its development stages?

We have a couple pictures on our Picassa page, but the story helps tie them together.

We did a bunch of CAD sketches to try to determine packaging. We quickly discovered that to make it all package like we wanted, a side-by-side wheel shooter helped a lot. That info was then fed to the prototyping team, and they set to work.

The first job was to build a CIM + wheels module. By random chance, we picked 1 CIM and 2 wheels. Based on some old math, we picked a reasonably high surface speed, and machined the module on the router.

We then attached the module to a bunch of 8020, and started doing a parameter sweep.



The obvious parameters (for us) to try were compression, and surface speed. Once the shooter was making shots into the goal reliably, we started collecting ball landing position data. They were using a pulse counter on the Fluke multimeter and reflectance sensor to count RPM to dial the RPM in accurately for the tests.



As you increase compression, there is a compression level where the spread shrinks, and then starts to increase. We picked that point.

The prototyping team didn't the standard deviation was quite good enough, so they kept working at it. Someone came up with the idea to offset the wheels vertically to put a little spin on the ball. That reduced the spread far enough that they were happy with it, and we shipped it with those numbers exactly. We haven't had to touch any of the shooter parameters all season, which is wonderful.