So this isn’t my idea but one of our team members brought this up. What would be the disadvantages of an “O-Drive”. Instead of an H-Drive where the module is in the inside, there are wheels on all 4 sides of a robot. So essentially the h portion of an h drive is moved towards the outer edges.
Extra motors, extra weight, can’t have an opening in the front for game pieces. What’s the benefit?
See also: Killough, kiwi
More even power (and thus acceleration) distribution between forward/reverse and strafing.
Reduced need for a suspension to ensure strafing wheel contact
If you position wheels in corners, you can absolutely have frame openings.
I’d also question the extra weight characterization. You may well not need extra weight compared to an H-drive. And, heck, in certain configurations you could even use fewer motors as well.
I remembered that OP posted a 148 teetering style center wheel h-drive a couple weeks ago so I assumed that’s what they mean’t for the front and back.
Increased power and acceleration while strafing is a fair point though
Sounds like you are talking about a holonomic drive tilted 45 degrees
Don’t listen to the haters, this is the drivetrain of the future.
Slap some 4" colsons on there and you’ll have yourself one spinny boi.
What I meant was similar to the literal O Drive but instead of a circle, it would be a normal 4 sided frame.
For streamworks we had a square robot with 3 3.25" omni wheels on each side, which I think is what you are suggesting. We did ok with it and I think we could have improved on it with more time. We did have an opening on one side.
Yeah, that’s exactly what I meant. In what ways could you have improved upon it?
What’s the benefit over a traditional kiwi/killough?
I would expect more traction since there are more than 4 wheels, although I don’t know if you will be playing defense any time soon.
I think that in general it’s really tough to have wheels on all 4 sides since usually most teams have an opening to intake game pieces, so that is most likely the reason it doesn’t get used a lot.
The field centric drive mode we implemented had some issues with reliability. I don’t recall if it was a gyro issue or something else. The drive team decided to drive it in robot centric mode. One of the things we tried to implement with field centric mode is to have the robot automatically rotate such that the nearest corner was pointed forward when driving around the field. We felt that was the most efficient way to move around the field.
Here is video of it when it had only 2 on each side:
So from reading the replies, I feel like I can conclude that there doesn’t seem to be any benefits to an “o drive” (if you want to call it that) compared to a more traditional h drive. You lose a lot of space on the edges where you could’ve intaked game pieces compared to a traditional h drive.
While that’s true of traction wheels, I don’t think it’d make much of a difference on an omni wheel as nothing’s digging into the carpet. However, assuming your wheels are belted together, you’re introducing friction when rotating.
I still don’t see an actual benefit to it outside of stability, and kiwi is stable enough. You’re also trading straight line motor power for diagonal motor power, which is generally less useful (however, I imagine it wouldn’t be that odd to run 6 motors on this hypothetical drivetrain, which would match or exceed a 4 motor kiwi in all scenarios).
Hmm, I suppose the ease of using a number of motors not divisible by 4 is a benefit, and if you put 4 on your forward/back wheels you’ll have power similar to a 4 motor tank (albeit with less traction) or mecanum when moving forward; not bad if you just want to strafe to aid alignment, and don’t really need to look like a swerve in terms of mobility. O-Drive wouldn’t have been terrible in Steamworks, honestly, but I would only consider it in niches like that where straight line speed and ease of alignment are crucial (those loading zones were far). In Power Up or Deep Space, where you’re doing a lot more turning and a lot less sprinting, it seems silly - and that’s how most games are nowadays.
Of course, all that applies to H as well. It’s probably my least favorite drivetrain.