Here is a swerve drive I have come up with that would be very achievable with a CNC router, manual lathe, and a manual mill. The goal was to design it so it could be manufactured entirely in house. We may or may not build something very similar, if not this exact module with some tweaks for our off-season project. Updates, more pictures, and a GrabCAD link will come soon. As always feel free to leave suggestions as well as ask any questions you might have.
Can you post a bottom right iso?
What does the connection between the module and mounting plate look like(what are you using for the rotation surface)?
Also why this versus a coaxial design? You guys always make beautiful robots so im wondering why you’d go for taking up more vertical space instead of lateral space in the frame with a coax design.
I plan to use a Chinese Silverthin bearing. As far as I can tell it is basically the same bearing but way cheaper. It is a 3.5"ID x 4.0"OD x 0.25"Thick bearing. The triangle shaped pieces are bolted to the 84t steering gear.
It makes the module plates Identical when machining them as far as I have thought through it. With a lateral design I would have to mirror some plates and then also machine them differently. I just wanted our first module, which will end up being used for this years game to be simple. With there being plenty of height in this years rules it’s not that big of a deal. Also lateral makes your frame taller unless you use a 775pro or miniCIM, which I also don’t want to do.
Where are you planning on sourcing this Chinese Silverthin? I might have need of one for an offseason project.
Swerve looks solid, although I wouldn’t volunteer to machine that bevel gear.
Very nice looking design. It appears to take a lot of inspiration from my design, which took a lot of inspiration from one of Aren Hill’s designs. Please post updates when you get it put together over the off season.
Good stuff. I like how you’re doing the bevel on the wheel, instead of relying on a press fit. Is the shaft of the VP being supported by a bearing on the plate? I’d put one on just to be safe. [Edit: Whoops! Ignore that, I didn’t see the picture you posted earlier]
Also, do you have a means of zeroing your modules? With the VP encoder, you’re not going to measuring wheel rotation but rather output shaft rotation, meaning that you’ll find “zero” falsely multiple times over a single rotation of the wheel.
This was the main reason we didn’t use the VP integrated encoder on our module this past year. We instead went with a encoder geared 1:1 with the steering of the module. It was very nice to be able to place the robot on the field and not need to make sure the wheels were pointed in the correct general direction or have an addition sensor and need to run a homing routine.
would a cim coder be good for a swerve like this? It would directly mount on the CIM, I haven’t used one before so not quite sure about the accuracy but it seems like that would be a pretty good option because it wouldn’t take up space and wouldn’t have the problems of the VP integrated one
I’ll PM you.
Yeah, I took a lot of inspiration from Aren’s design, and yours, but also many other designs as well.
I plan to use the WCP Hall Effect sensor. Shown here: https://imgur.com/a/fVxFl8y
The only thing I am uncertain about is how this sensor should be mounted/used. I gave it my best guess on what I thought was right.
If you do this, you will have to zero the motors before every match. You should look into a 1:1 absolute encoder.
If you can send me the source of these cheaper silverthin bearings that would be awesome :]
Also where are you planning to purchase your bevel gears from?
Can you post in here please?
Enough with the bearing secrets people.
We used these last off-season and during the 2018 season. Took about 5 minutes of searching on Amazon. Also it’s a generic bearing aprt number so you can find a ton of different suppliers that have the same bearing. Also go to the similar items to find varying sizes similar to this one.
No bearing secrets here. The bearings I am looking at getting are not genuine silverthin bearings that’s just the only way I could think to describe them. When I find a reliable supplier on Alibaba I will post a link with a part number of what I plan to order. Sorry for it coming off like it’s a secret, I just have not found a place or price for what I am looking at getting.
Amazon’s nice and all, but you can get the same bearings for $6 on eBay. I don’t have any links, but if you search up “6816 bearing” on eBay you’ll find dozens come up. The only problem is that shipping takes about a week to two weeks, but if you order before the season it’s probably worth it.
Edit: I’m a liar. It’s $8 here. I swear I’ve seen some cheaper though.
If I don’t end up finding the thin section bearings I will probably get those. Hopefully I can find the thin section ones.