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Unread 27-04-2009, 07:10
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sgreco sgreco is offline
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AKA: Steven Greco
FRC #2079
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2007
Location: Millis
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Re: Questions about crab/swerve drive.

Quote:
Originally Posted by Vikesrock View Post
Steve, I don't know if what Adam saw was similar, but I saw at least two crabs this year that would not sustain the axial loads put on them by rapid change in wheel direction or by being pushed across the carpet perpendicular to wheel direction.

I am far from a mechanical expert (electrical and software are more my thing), but I am near positive that the two crabs I saw would fail in an FRC game on carpet. One team was definitely aware of this and the module was designed this way because of the game. I didn't get a chance to talk to the other team at all to see if they knew what issues they could face if we move back to carpet next year.
I agree with what you are saying about crabs failing. For an example, my team used made a swerve drive that worked very well, but only on Regolith. If we put higher friction wheels on and drove it on a rug, it probably wouldn't be as successful. We were aware when we built it that the system would only work on regolith with lunar wheels, but that's the only place it had to work. You just have to keep in mind what the challenge is and what the objectives are when you are building it.

For those of you asking questions about swerve for the future, I would really look into 111 and 118. That's where my team got a lot of inspiration from.

If you are interested in looking at my team's swerve, here's a link to a brief description and some photos. http://alarmrobotics.wikispaces.com/Swerve+Design+09