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Unread 24-04-2009, 13:56
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EricH EricH is offline
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
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Re: Questions about crab/swerve drive.

You're all forgetting one thing.

We don't know that a swerve drive will be good for next year's game.

So, by "next year", you really mean "next fall, as a prototype", riiight? You see, crab/swerve drives are pretty complex, especially compared to tank drive. So you want to do at least one before it counts, just to help you do the one that counts (if you do it). Move up your schedule and do it in the fall, then evaluate it at the start of build to see if it'll be good for the game.

Now, for some help.

1 CIM per side is still probably too weak. It'll work, yes, but you really want 2, or 1 per wheel module.

There are a number of setups, with the 2 most common being a coaxial crab and a more standard swerve. 118 uses coax, 148 used coax last year, and some other teams do as well, I think. In this setup, all the drive motors power all the wheels. A second rotation shaft is used to rotate the modules. You could set this up to act as either all 4 steer together or as a 2x2.

The other main option is to put the motor in the drive module. That's a little tricky on the wiring side, but it's a bit simpler mechanically.
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Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

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