One of the big debates @nuclearnerd and I have had is he isn’t sure swerve forks that are printed (especially on consumer grade printers without fiber) are stiff enough for FRC use. That prompted me to start looking at what other assumptions we’ve always just made about swerve in FRC. Why do we need azimuth bearings, can a delrin bushing work? And you know what? Combat robots use bushings in their drives, could we? With those and a few other questions that I’m too dumb to know not to ask I set out on a design (mostly fueled by insomnia). My constraints - 2.5D single operation pieces only, simple lathe operations, and printed parts in NylonX. I’ve also removed the requirement of having an absolute sensor on the azimuth because for my purposes of software development I can zero the modules manually. Though there is space for a printed pulley to get a 1:1, just didn’t spend much development time on it because it’s not pertinent to my needs.
Delrin bushing for azimuth, printed forks tied together with a dead axle shaft, and TTB wheels opened up to allow for a 5/8" OD bushing. As pictured it’s geared to ~15fps free speed though the spacing allows for a range down to 8fps in ~1fps steps. (This will vary depending on what you use as your drive motors). Main drive shaft is the only complex lathe operation requiring a 3/8" hex being turned down to 10.75mm (thunderhex), down to .25", and then drilled and tapped for retaining screw. The odd colored panels are a feature I’m playing with to identify modules more easily independent of the frame of reference.
Per cost module comes in around $235 without ESCs or fasteners, but that price can go down easily by using the hdhex motors that come with the UP gearboxes. Estimated print time for the printed parts on my Mk3S in CF Nylon come out to just over 8 hours, plus some spacers (probably another hour of print time, the spacers are all very thin pieces).
And then because why not, here they are mounted on a 16x16 chassis…
Maybe all of this is stupid and bad ideas, I’d love to hear from folks who have tried similar stuff. Mostly shared because a) posting swerves seems to be the hip thing to do these days b) spark a discussion of why some of these things are bad ideas c) inspire folks to start discussing other potentially stupid ideas.
Now if I can get ROS2 controlling my motor controllers that I bought on firesale from Diligent I’ll have an excuse to try it.