So I made an autoshifter in CAD using a weird custom dog, parts from the GEM gearbox (ring gear is a measely $10 vs. $100 for other internal gears) modified for this purpose, and a custom wheel made to fit the ring gear.
The way this works:
0. There is a primary reduction from CIM to wheel shaft.
1. The shaft is spinning in one direction, say, clockwise. The dog is keyed to the drive shaft and spins with the shaft. It also engages with the hub of the wheel, to direct drive the wheel from the shaft. The dog is "locked" to the wheel due to the acute angle of the teeth. The wheel spins clockwise with the shaft.
2. There is a collision with another robot and the robot gets into a pushing match. The driver flips and switch, and the CIM then reverses direction- now the wheel shaft spins counterclockwise.
3. The dog spins with the shaft. However, now the dog is no longer "locked" in place due to the shape of the teeth. Now, the obtuse-sloped side of the tooth contact the like side of the wheel hub and pushed the dog into engagement with the sun gear of the planetary gearset.
4. The dog "locks" into place with the sun gear due to the acute angle of the teeth. The sun gear spins the planet gears which transfer power to the ring gear. Due to the nature of planetary gearsets, a counterclockwise rotation of the sun gear with the planet carrier locked produces clockwise rotation of the ring gear. This means that the ring gear, which is locked to the wheel, now spins clockwise. Thus, the wheel still spins clockwise after the shift.
Essentially, all you need to do in order to shift is the reverse the direction the CIM is spinning in.
Obviously, this poses the problem: how do you go backwards if you reverse the CIM to shift and the wheel only goes forward?
The answer: you can't. This is only suitable for swerve drives for this very reason. You have to turn the wheel to go backwards. RS-775 18v are suggested for turning motors.
In order to manufacture the parts in the CAD, you would absolutely need at least a 4-axis CNC due to the weird dog and mating gear/ hub. Not to mention the wheel itself. Because my team lacks the resources to do this, I decided it would be fine to release my CAD of this.
There's probably a ton of errors in the CAD right now (I've only cadded a few of these, and this is the first actual possible swerve module with it) but I wanted to see what the CD community thought of this idea quickly. The CAD is missing bearings, circlips/ eclips (I use the latter), and a miter gear on the primary shaft. Reduction is accomplished with the sprocket for an adjusted 20.0fps high gear and 7.5fps low gear. This is can go down to something like 18fps high gear pretty easily just by increasing the size of the versasprocket. I only had a 34t versasprocket on hand in CAD, but 38t would be preferred.
I use SolidWorks, so if anybody would like the native SW files I have those on hand for the weird dog geometry.
Files in STEP format for download here in a zip folder:
https://drive.google.com/folderview?...&usp=sha ring
EDIT: Forgot to say, feel free to slam this however you feel. Anything at all. I have designed a ton of swerve modules (upwards of 15) but none of them have been built. So any input at all will help with the next ones.