The team was busy this summer and preseason working on our swerve drive. We ended up making some modifications to the 2910 MK2 swerve modules and 3D printed a majority of the module. Everything was printed in PLA on a Prusa MK3. Big credit to 2910’s design that even 3D printed they held up great and allowed us to do some serious software development with them.
One significant change is that we 3D printed the main central pulley. It’s a difficult part to machine and we felt a 3D printed version would hold up for our testing. For the main pulley, we changed a few pieces of it in the CAD, but then we took the STL and used a different tool to add back the extra pulley teeth and regenerated an STL to print. You can find that on our thingiverse account (link here).
Developing the swerve drive solution and autonomous code was one of the challenges as part of our preseason mock build week. If you’re curious you can see a small demo of it here: Google drive video link. As a bonus in the video you can see the other robot built during the mock build week challenge on the bottom left. That one was a vertical suction climber robot (lovingly called SpiderBot) able to attach and detach to the underside of a platform via driver controls. If you’d like to see that one in action let me know and I’ll post a link.
This is kind of a random and general comment, but I’m not seeing a lot of love for the fantastic .stl alternative, .3mf. Files are smaller, circles are actually circles, they import and slice faster, and almost every CAD package can export to them now. (They also handle multi-color much better, but this is FRC so meh)
I have a feeling it might just be a lack publicity, but we made the change very quickly in 2017 when we started printing more complex and larger parts.
I certainly like the idea, and you executed it very well. The beefed-up base plate looks great! Did the motor plate still hold up despite the lightening features?
A possible place to take advantage of the capabilities of a printer would be to integrate the motor and encoder plate as one part, and hopefully reduce part count on that front.
That’s a really interesting point, Troy! I’ll bring this up with the team and see if it’s an option for us. We’ve had so many issues with STL files that it’s certainly worth trying 3mf.
I certainly like the idea, and you executed it very well. The beefed-up base plate looks great! Did the motor plate still hold up despite the lightening features?
A possible place to take advantage of the capabilities of a printer would be to integrate the motor and encoder plate as one part, and hopefully reduce part count on that front.
Thank you! The base plate modification eliminated a ton of the flex. We put bolts through the horizontal holes to give it rigidity.
The upper plate ended up being made with poly since we had time to make those before we had to leave the school for the summer construction work. If we were to 3D print them we would likely remove the lightening.
Very cool, and a neat idea for testing! If you use swerve this season, do you plan on getting a milled pulley?
We’ve considered it, but feel that depending on the challenge a 3D printed central pulley would work just fine for a real season. There’s enough contact across the pulley that the loads are well distributed. Would we drive this off level 2 in 2019? With a metal base plate, maybe. But for a flat field game we would definitely stay with a 3D printed central pulley.
