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Unread 03-10-2011, 12:59
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FRC #0973 (Greybots)
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Re: pic: FRC973 Presents Emperor Swerve

Quote:
Originally Posted by Gdeaver View Post
The encoder issue seems to have split in 2 directions. I was talking about using quadrature encoders to provide absolute position for the swerve steering. If I understand it right, the crio is configured with 8 counters. So if 4 4x encoders are used for swerve wheel absolute position then the counters are used up. I suggest that 4 analog voltage absolute encoders be used for wheel position and then the counters can be used for wheel velocity or distance and any other bot mechanism needs. On our bot we used 4 analog absolutes for steering and 1 for our arm. We just used a tachometer on the wheels so we have plenty of counters for future needs. My point was quadrature with index is not the best strategy for measuring wheel position for swerve.
We are using the quadrature encoders for wheel steering. This is for the reasons I stated above (Never having to zero sensors is a really big deal to us). You'll also notice most industrial applications use an encoder + zero of sorts over analog sensors.

We also aren't measuring wheel speed at all. Instead we opted to put a pair of follower wheels (oriented x-y obviously) and a gyro for all position and velocity calculations.

Last edited by AdamHeard : 03-10-2011 at 13:10.
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