So I’m a little late to the Differential Swerve party (11 years late, Ian from 1114 was first as far as I know).
Here is my (and some quite helpful others) take on the rotating module portion of a differential swerve. This particular module has been an offseason project for myself, and a now alumni Ginger.
The final module will include 2x 775pros, one driving each 84t gear.
Final overall ratio will likely be 14.6:1 on a 3x1.5" Colson, with the final stage of gearing being a 46:12 upduction (I know it’s not a word, but I like it).
There is a lot of VersAluminum in the center of an 84T VEXpro gear, so it got used to make a bevel gear.
Final speed for this module will be ~16.7fps free, with an effective tank drive wheelbase of 11.5" (if this were a tank drive, the wheels would be 11.5" apart, this is the best metric I’ve come up with for relating the steering sensitivity to something I have more gut experience with).
The 2x 84t gears are supported relative to the module center frame by 4x SG15U bearings each, running on a round contoured raceway. The central 4140 steel disc will have some qty of RM1 V-bearings supporting it relative to the robot frame.
Haven’t weighed it, don’t really care for that as a metric, it doesn’t weigh much.
The diff swerve concept and a graceful implementation have been on my mind for awhile, and I’ve been lucky enough to find enough other people to be part of the conversation that it has made some strides, credit to Ian Mackenzie, Alex Zettler, Dillon Carey, Ginger Schmidt, and Spencer Witte.
Feel free to ask any questions and Ginger or I will answer them.
(photo credit: Steve Silverman)