Team 2338 swerve drive peer review

[R.C.]

Originally Posted by AdamHeard

I looked over the design, and I really suggest some substantial changes.

The sideplates need to be beefier, 1/8" thick with that much removed for a module that tall..... I obviously haven't run the math on it, but I'm leaning towards scary.

The turn table scares me.... a lot. They don't handle sideload well (and even with the bottom support.... there will be sideload) and I just would never trust them in a critical application. I highly, highly, reccomend a bushing or bearring for the module rotation.

The chain run, why does the bottom shaft need to rotate and have external sprockets? you should put the sprockets between the plates, make the very bottom shaft stationary (ideally built in such a way to rigidly attach the sideplates, adding strength) with a wheel that sits on bearrings and a sprocket bolted directly too it.

Good choice on the bevel gears, not sure what factors influenced it, but they're the same gears 118/1625 (and we used on our crab) used.

Adam,

You made me curious so I had to open up the cad file, but I share all the same thoughts Adam has stated. But FIRST, great design and keep creating awesome stuff. I really like the setup, it just needs some tweaking:

-The plates are way to skinny, you should run COSMOS or some FEA. If you need help, pm or email me. I personally would go with 1/4" thick plates, but you might be able to get away with 3/16th's with less pocketing.

-As Adam also pointed out, why key the bottom shaft. A cleaner way to do it would to buy a bigger sprocket, just big enough so that the sprocket can fit an andymark bolt pattern on it. The wheel should have a bearing on it with a sprocket bolted to it. The first outer sprocket should be moved inside and I reduced the current hub by 3/8ths. Here is a link to the modified CAD file (IMAGE-1, btw hope you didn't mind me modifying the CAD file).

-Also on the right side of the uploaded pic, I flipped the bearing so that the hub of the sprocket pushes up agianst the bearing. On the other side you are going to need collars to keep the bearings in the right spot (unless they are pressed in).

-As for the sprocket that turns the module, put a bearing instead of the turn table. Smaller turn tables tend to be weaker and a bearing can do the job just fine.

-Also make sure there is a spot to mount an encoder, you can either mount it on the module or on the gearbox that powers it. I have never made a crab drive and maybe I'm wrong about the encoder thing, but Adam or Aren should be able to ellaborate on the use of an encoder.