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Unread 08-11-2016, 10:28
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Ari423 Ari423 is offline
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Re: Swerve vs. Butterfly Drivetrain

Quote:
Originally Posted by Taylor View Post
Does a butterfly-style drive necessarily imply the use of pneumatics? For a robot design that does not otherwise incorporate pneumatics, it is certainly important to factor in the space, weight, wiring, and programming required for a pneumatic system to support the drivetrain.

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Also, it's important to consider levels of implementation. When I think swerve, I think 16, 71, 111, 118, 1640. Those aren't representative of the 'average' swerve drive robot.
If a butterfly drive succeeds, it's pretty nice. If BD fails, it's still a completely capable 4WD robot*. However, there hasn't really been a team that has used it consistently enough, and at a high level of success, to be the standard-bearer for that configuration.

*the same can be said for a failed SD, but mechanical locks may be needed to achieve that.
For butterfly drive you need to physically switch which wheels are touching the ground. This movement requires fairly quick actuation, a very large amount of force at stall (enough to support the whole robot), and only two positions. To me at least, those restrictions scream pneumatics. I guess theoretically you could use motors (big servos maybe?) but that would be way more complicated than with pneumatics where all you need is a cylinder pushing between the module and a hard attachment to the chassis.

IIRC 148 has used variants of butterfly drive in a number of games (I know they used it in 2010). They haven't used it every year like some of the team's above have used swerve, but if I had to pick a team to be the standard for butterfly drive, I would pick them.
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