paper: FRC1189 2009 Shooter Gearbox Development

Thread created automatically to discuss a document in CD-Media.

FRC1189 2009 Shooter Gearbox Development
by: kramarczyk

This paper details the development process of a gearbox for the Gearheads 2009 robot in dirty iterative detail. It also serves as a mechanism to capture team intellectual property.

This whitepaper is intended to follow the development of the custom shooter gearboxes that were used on the 2009 Lunacy robot. It also includes background on the shooter, COTS options that were explored, why custom gearboxes were used, and the process used in developing the custom gearbox. Additional learning related to the Fisher-Price gearbox that can be applied to future projects is also included. This paper is not intended to address basic manufacturing items such as measuring and hole making process nor is it intended to explore the overall design decisions of the 2009 robot.

2009_Shooter_Gearbox_Development.pdf (1.28 MB)

Mark -
This is a fantastic resource and one that I think will really wake up alot of folks to the true versatility and usefulness of the FP motor and gearbox. I especially liked your honest description of the all-too-common-in-FRC last minute design constraints that played into your decisions. Plus, the narrative form really makes the paper fun to read!

Thanks for sharing!


I’ve hemmed and hawed about posting this for most of the summer. I wanted to get the FP info out there since I don’t know of any consolidated source. Some of it is spread through a variety of CD posts, but can be hard to find. I really wasn’t sure if I should include the team oriented narritive, so I’m glad the dirtiness of the iteration played well.

This is a fantastic resource, thanks.

I know I told you this when I saw this several months ago, but this is a FANTASTIC paper.

Was the ability to aim left/right ever used? How effective was varying the speeds?

Yes, it was used when pinning someone at the trailer hitch. The varying speeds did work with the camera, but the game ended up play faster that we thought and as a system (camera through to hardware) it wasn’t fast enough to automatically track. Fortunately there are manual options for left,center, right at a contact distance (~3 ft). Did it work as well as I would have liked, no. Did it work, yes. As the balls broke, down the variation in game pieces caused problems.

Great paper!
A must read for anyone wanting to learn more about utilizing FP motors.

Great paper and thank you for your effort to pass useful info along. I would bet there will be some FP motors and gear boxes in this year’s KOP.

One comment: As I recall the FP motor air intake is on the front face and the exhaust is at the rear where you can see the fan blades. Would it add to reliability and longevity to add some openings in the gear box to allow air intake to keep the armature a little colder? Cooler armature would result in cooler winding lowering the resistance with resulting possible increase in output power.

Keep up the good work. … jon

Has anyone ever machined a heat sink to fit over the FP motors’ body? I would think that if you can get a snug metal-metal (or metal-thermal paste-metal) fit, you could probably cool the motor quite effectively by increasing the volume/surface area of heat dissipation and decreasing the effective power density.

In 2008 we used part of a quadcore cpu heatsink that was round, and simply spread it wide enough to fit over the fp motor, worked quite well.

you can see it in the lower left of this pic

I’ve heard this heat sink worked wonders on 1024’s 2008 robot.