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Unread 08-12-2013, 21:20
gpetilli gpetilli is offline
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FRC #1559
 
Join Date: Jan 2009
Location: Victor, NY
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Re: Team 2471 swerve drives

Quote:
Originally Posted by Ether View Post

Gdeaver alluded to the importance of swerve/omni Driver Interface (DI), and that segues into a question I've been wondering about lately.

Does anyone know of a team who has implemented a DI mode I will call1 a HaloAR (AR=Auto Rotate), as described in this thread posts 5, 6, and 9?


1until someone informs me that such DI has already been named
Yes, FRC1559 is planning this for 2014. We are implementing a fusion sensor of a compass and gyro in a velocity PI loop. The gyro is the P velocity feedback and the compass is the I feedback (conceptually it directly reads the integrated error).

When turning, the current heading is updated to the current compass. When not turning, the PI loop is closed loop to hold the heading (which helps reduce affect of gyro drift).

At initialization, the robot snaps a zero heading. At any time the driver can press a "hat" button to command the heading to be one of the primary orientation (plus maybe feed station). The PI loop will drive the orientation while the driver continues to command XY translations.

We have this working with our asymmetric Killough drive, but only have about 30min of testing under our belt. Focus has moved to a similar fusion PD loop for X and Y with a follower wheel for velocity error P and an accelerometer for the differential error D.