
02-07-2011, 10:33 AM
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Registered User
 FRC #2168
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Join Date: Nov 2010
Location: CT
Posts: 8
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Re: Sync Two Jags
Quote:
Originally Posted by kamocat
You can try using one in %Vbus, Vcomp, or Current mode, feeding it the value you've gotten from the controlling Jaguar.
For any of these options, you'll want to do some processing to the data to get something acceptable. The trouble is, for low speeds the Jaguars like to return lots of zeros. (though perhaps my PID is tuned a little too high) When you tell a Jaguar in %Vbus or Vcomp to go "0", it doesn't ramp down, it just stops. This leads to very jerky movement. Perhaps a running average of the last 5 samples would work, or perhaps you just want to ignore all the zeros.
In Current Mode, the main issue is simply lack of accuracy. It's +-2 Amps below 8A, and +-1A above. That means you better have a pretty big load in order to use it. However, large loads are usually where the double motor is necessary.
I'm planning on wiring the encoder to both motors, and having the PID independent. Because both Jaguars are subject to the same conditions, I'm hoping I won't get significant integral windup. (Also, the integral is reset when the Jaguar output is "0")
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Is it possible to wire one encoder to two jags?
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