Best Drive Train

[Siri]

Originally Posted by runneals

1) It's WAAAY more reliable then swerve. We never once had any major issue with our butterfly drive train this year (with the exception of breaking an omni during practice because we ran over a floor power outlet. We can also lose pneumatics (such as we did in final matches #2 & #3 at North Star and we can still drive just on omni's. If we lost an encoder with the swerve drive (ie. got unplugged), which happened a few times too many last year, we couldn't drive and it took some power cables with it.
2) It's WAAAY easier to fix then swerve. To fix a butterfly module, all we had to do was to unbolt 1 bolt and we could easily change out the module ("plug-and-play" if you will). We would just have to remove 2 additional bolts to get to the actual drive train itself. Now to fix the swerve drive, we had to work in crammed quarters trying to unbolt a bolt (which wasn't fun) and to fix wiring issues.

These two are not functions of concept but rather of execution. We are also in an exactly 0 failure year, and most of the components have never failed once in 4 years. Preventive maintenance on what are very few potential failure points (swapping wheel treads, and...well, basically that. Maybe a few things that take longer to pick up the wrench than to fix) is done off-robot after a quick switch; all 4 in maybe 5 minutes. There are very few things that could go really wrong that would require serious disassembly to fix.

Work, resources and weight I agree with (though ours isn't so long), but that's not the initial selling point you mentioned, which is why I asked. Motors I'm less worried about after this year. I can't imagine what I'd use all of them for. We did fully independent swerve and a 30 point climb with a shooter and allocations for a floor pickup and still didn't manage to run through them all.

Originally Posted by jbsmithtx

Saves motors, time, and is incredibly easy to use. If you want a truly great swerve, you have to use 8 motors, which is a lot of the motors you have and use. An octocanum or butterfly is just as maneuverable and only uses 4 motors, but there is no pushing power to the side. Why is pushing power on the side needed? And as said, too much easier. Swerve is cool but fairly wasteful.

Actually there's no pushing power along any other axis, which is a huge advantage when used correctly, but I understand that's not your point.

I have never seen an omni robot exhibit actual holonomic drive--full control of orientation while translating along any vector. Is this a function of physics or of execution? I can't tell from your page how the butterfly modules are oriented. If you had a real-time sequence of translational vectors and orientation headings, could (theoretically) you move through them simultaneously at will? (If so, remind me to make you do that when I want to push you )