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Unread 02-02-2011, 15:28
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Re: CAN, PID, Mecanums

Quote:
Originally Posted by Ceebs03 View Post
My team is using mecanums and CAN, and I want to use the KOP encoders and the PID on the jags to make sure the wheels spin the right speed.

I believe to do this I need to open each motor individually in speed mode, set the PID values, and then plug them in to a four motor drive of "existing motors"
Yes.
Quote:
My questions are:
Do I need to change the holonomic drive VI to make it work with speed mode?
Yes, the Holonomic Drive VI is designed to work with a magnitude of -1 to 1. You can find a "max output speed" parameter in the RobotDrive ref, and multiply this as done in Arcade Drive.

Quote:
Do I need to use speed mode to do this, or is there a way to do it with Percent
VBus (which should work unmodified with the holonomic drive VI, right?)?
I would highly recommend using speed mode. Percent vBus will work with the default VI, but it doesn't provide good low-speed control or repeatability.
Quote:
I need to "tune" my PID right? what is the recommended method for doing this? I know trial and error is common, do I need to test with the whole robot, or can I use BDC-COMM?
Trial and error is probably best, because it will give you an understanding of how the different parameters affect it. You can do this with the BDC-COMM, but be sure to write them down; these parameters are not retained when the Jaguar looses power.
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