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Unread 09-04-2016, 20:42
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Omar Zrien
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Re: PIDController + Latency - related issues

Quote:
Originally Posted by Pault View Post
I'm not sure what options are available in LABVIEW, but the simplest way to do this in Java, C++, and onboard PID with a Talon SRX is to just add a feedforward term.

To add feedforward (kF): remove all other constants, set the setpoint to a specific speed (I've heard 3/4 of max speed is usually pretty good). Then increase the kF until the actual speed matches the setpoint. From there, you can start to play with small values of P and I to get your controller more accurate.
This is better explained in section 12.4. Velocity Closed-Loop Walkthrough – Java, Talon SRX Software Reference Manual.

Maybe OP can start with just describing the problem symptom. An oscillating velocity-closed-loop-output when the target is fixed is a common problem, usually solved with proper gain tuning. Adding an F-term will help, allowing you to have a sharper P-gain with less overshoot.
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