PID Tuning in Tuner X

CTRE has an excellent guide already that explains how to properly tune a PID loop. We strongly suggest following the steps in the guide.

After you follow this guide, come back here and we'll explain how to implement it.

Drag a gain and watch what happens. Find out what too much kP looks like here, where it costs nothing, rather than on a real gearbox.

Switch between the three. The arm holds an angle, and gravity pulls on it everywhere, so it never rests at zero output. The flywheel holds a speed. Nothing drags it off target, but holding that speed costs output, and a game piece steals it at once. The elevator is the other gravity case, a constant pull.

Before running this, fully power cycle the CANivore and mechanism to prevent any old positions from being read.

1. Open Signal & Control and add the TalonFX you are tuning.
2. Plot two signals: the target and the measured position (or velocity for flywheels). Put target and measurement in one group so you can read the gap between them.

Follow the CTRE tuning guide on your actual mechanism.

A tuned arm sounds like one motion and then silence. If the motor is still working after the mechanism stopped, kP is too high.

Nearly everything that goes wrong on a mechanism looks like one of these. Read the plot, not the mechanism.

Runs away

Wrong direction

Error grows instead of shrinking and output pins. Disable now. The sensor or the motor is inverted, so go back to Motor Setup.

Buzzes

Too much gain

Voltage chatters and the mechanism hums at rest. Cut kP before reaching for kD. Damping will not fix a loop that is too stiff.

Falls short

Not enough output (position control)

Error settles at a constant gap. Increase your kP to correct this, likely followed by a kD to dampen the overshoot.

Drive the mechanism to its target in both directions, from a standstill, three times. You are done when all three runs look alike.