To close out 2023, 1706 would like to post everything we’ve created this season. Hope everyone is as excited for Crescendo as we are.
This was our first year using onshape as our primary cad software, and there were a lot of learning experiences along the way. We highly recommend using onshape based on our experience.
2023 Whiplash CAD
This is the main robot assembly for our competition robot. As most probably know, this year we set out to shoot the game pieces instead of placing them. Though we knew it would be a challenge, we saw a high possible skill ceiling if we took this path. As we thought at the beginning, this path was filled with challenges and setbacks, but after a lot of trial and error, we eventually pulled together a robot that we are all extremely proud of.
2023 Outreach Demo Bot CAD
Our goal for this project was to create a small, classroom-sized robot to use for outreach events. We didn’t have many criteria apart from being light enough for a single person to carry it and have the form factor to fit within the trunk of a small sedan. We chose the 2017 game fuel because it is relatively easy to work with, and we have a large surplus.
2024 Swerve CAD (Custom Flipped Motor Design)
For a fun exercise, we decided to attempt to design our own flipped motor swerve over the off-season.
I’m not a programmer myself, but if anyone has questions about code, I will let our programming team answer.
2023 Whiplash Code
2024 Swerve Code
FRC 9401 Offseason Robot Code (Shared on their behalf)
For your outreach demo bot, what made you choose a rack and pinion style intake, and also how has the rack dealt with constant use? Did you have any problems with teeth shearing off or anything like that?
Yes! We have made some prototype modules and may end up using this design for 2024. We would need to decide soon after kickoff If we want to have the parts made. Some are pretty custom and need to be EDM so we want to be sure before having them made. One thing we really like about this design is the steel azimuth ring gear that we have pressed into the aluminum azimuth hub. This retains steel gear teeth but gives us better weight savings. (Prototype module is about 5.7lbs with 2 NEOs and everything installed)
For the question about gear ratios we were inspired by Rev and have it designed to use 14T pinions so that we can have a ratio spread across 12,13,14T. We may copy SDS and make a custom 15/16T plate if we decide we need higher speed. Right now the 14T gives approximately 16.9ft/s free speed on the NEO. Swapping speed ratios requires just swapping the translation gear pinion.
We took inspiration from 254’s robot this year. As for wearing, both the rack and pinion seem to be holding up extremely well. This was our first time cutting gears out of polycarb, and we’re really happy with it.
Yes the worm gears were purchased from McMaster carr iirc and then we machined them out to a rounded hex bore. Then a thrust bearing and block were added on the end so that the worm gears axial reaction force would not damage the planetary. (On our first revision with the worm gears the axial thrust would tear out the 1/2" hex output of the versaplanetary)
It took a few iterations, but our lead build student then became an expert on shimming the axial thrust bearing to minimize backlash as much as possible and we were Happy with the results.
The top plate actually ended up never getting installed as the versa handles thrust into the planetary ok.
I’ll try to get a picture of the real thing before kickoff and upload.
I believe the versa we used 7:1 stage so should be 140:1 overall with the worm gear. This is with a NEO 550 set to 20A current limit. Should be about 26N-m not including gearbox losses. Plenty of torque and not backdriveable, this was extremely important that we had pretty good stability when intaking and shooting the cones because they were very sensitive to pickup height and angle.