Over the past few offseasons Frog Force has put a good amount of time into developing a swerve for competitive use, this past offseason being the most successful. We would like to share our experiences with the community because if it weren’t for others who have shared their own resources, then our efforts would not have been nearly as successful. Thank you to teams 33, 2910, 2767, 910, 1323, 3707 and all the other teams who have released resources and helped to inspire us.
2019 Offseason MK3
The team had never felt confident enough in a design before to release to the community or compete with until this rev. This version of the module included the lessons learned from all of our previous attempts, but was inspired heavily by 33, 2910, and 1323’s designs. It’s also the team’s first version to go from CAD to full chassis. All of the plates were done out of 6061 on a Shapeoko XXL(which was painful but free) and heavily utilized the Markforged Onyx. It was designed to be fully enclosed, but that concept never really made it to reality.
Basic Stats:
- 13.16 ft/sec adjusted speed (Neo on 14:32, 20:40 Bevel, 3in Wheel)
- 204 rpm azimuth (775pro onm 12:100, 20:44, 24:120 Belt)
- 1:1 CTR Mag encoder on module rotation through Onyx gears
- 6.8in x 8.9in x 7.3in footprint (5.8in x 7.9in inside the frame)
- 6lbs per module
The team competed with these modules at Kettering Kickoff with a new elevator and intake. Although the stats didn’t look too good(0-6 rank 40) the modules drove well, holding up to the small sample size of 6 matches, and it was a great learning opportunity. We found another number of improvements to make to help easy machining, assembly, and repairs which led us to decide to make a 3.5 module.
Elbowvater Robot CAD Link: https://grabcad.com/library/frc-503-2019-offseason-robot-1
MK3 CAD Link: https://grabcad.com/library/frc-503-2019-offseason-v3-swerve-1
2019 Offseason MK3.5
With all of the lessons learned from MK3 we didn’t think we could go into a competition with a module that we knew could be better, so we made a half rev. We only made one module of this to test the assembly process and do basic testing, but a majority of the parts are based on the same concepts as the MK3.
Basic Stats:
- 13.16 ft/sec adjusted speed (Neo on 14:32, 20:40 Bevel, 3in Wheel)
- 162 rpm azimuth (775pro on 8:40, 10:46, 24:120 Belt)
- 1:1 CTR Mag encoder on module rotation through Onyx gears
- 5.8in x 8.2in x 7.25in footprint (4.8in x 7.2in inside the frame)
- 5.5lbs per module
Improvements:
- Changed 32dp 775 pinions to 20dp and moved inside the two plates
- Changed small bevel shaft retention to snap rings instead of bolts
- Changed top plate to nylon to ease machining
- Switched to custom wheel
- Smaller packaging size
- Weight reduction
- Eliminated all the captive nuts
- Increased azimuth gear ratio
MK3.5 CAD Link: https://grabcad.com/library/frc-503-2019-offseason-v3-5-swerve-1
Overall the team is very proud of the determination of the students and mentors to keep moving through the many failures and learning experiences this process provided over the past few years. The modules aren’t the coolest ones out there for sure, but it is a great stride in the right direction. We have no idea if the game will lend itself well to a swerve this season but if it does we hope to be able to put these modules to the test. @VPanyam and I are more than happy to answer any questions you got! 