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Unread 10-02-2017, 10:11 PM
Oblarg Oblarg is offline
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Re: Tuning a PIDF follower on a robot with high gearing

Quote:
Originally Posted by Jared Russell View Post
If you want to be a bit more accurate, you can compute a feed forward acceleration term for your profile that takes this into account, and apply a gain to that instead.
Assuming that you're tracking your profiles well enough that actual speed is sufficiently close to desired speed at any given point in time, then wouldn't a feedforward structure of "intercept + Kv*velocity setpoint + Ka*acceleration setpoint" properly account for this? Unless I fundamentally misunderstand brushed DC motors, torque depends only on the difference between applied voltage and back-EMF. The "intercept + Kv*vel" portion of the FF should account for back-EMF plus the voltage required to overcome frictional forces, leaving the "Ka*acc" term to account (hopefully correctly) for your desired acceleration on top of that.
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Member, FRC Team 449: 2007-2010
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FRC Drivetrain Characterization

Last edited by Oblarg : 10-02-2017 at 10:15 PM.
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