User Manual

PI Editor
Enables you to adjust the control loop feedback parameters for Roll, Pitch and Yaw.
The proportional term (P) produces an output value that is proportional to the current error value.
A high proportional gain results in a large change in the output for a given change in the error. If the
proportional gain is too high, the multicopter will overshoot and start to oscillate. Since the control
loop compensates for errors 400 times a second too high a P gain will result in a high frequency
oscillation. If the proportional gain is too low, the control action will be too slow to react on the
multicopter and it will be difficult to control.
The contribution from the integral term (I) is proportional to both the magnitude of the error and
the duration of the error. The integral in a PI controller is the sum of the instantaneous error over
time and gives the accumulated offset that should have been corrected previously. If the integral
term is too high, the multicopter will start to oscillate. Since the I term is related to the duration of
the error over time, too high an I gain will result in a low frequency oscillation. Too low an I gain will
result in a less “locked in” feeling.
PI gain adjustment process
• Go to the "Receiver Test" menu and use the transmitter trims to set the Roll, Pitch and Yaw
values to zero.
• Switch off Self Level.
• Set the I gain to zero for Roll, Pitch and Yaw.
• Hover the multicopter and move in one axis (Roll, Pitch or Yaw) and quickly centre the TX
control stick.
• Increase the P gain until the multicopter starts to oscillate when the stick is quickly centred.
• Decrease the P gain slightly to remove the oscillation.
• Repeat for all three axis (note, if you have “Link Roll Pitch” set to “Yes” in the Mode Settings
menu then adjusting the PI gains and limits for Roll will also adjust the Pitch settings).
• Increase the Roll and Pitch I gain until it flies straight forward/sideways without pitching up
or down. It should feel more “locked in”.
• Increase the Yaw I gain until Yaw feels “locked in”. You will see most impact on a tricopter.
Leave as default for quadcopter.
Note, if you have I gains set and you operate your multicopter on the ground, you will find that
motors will start to increase in speed while others decrease. This is the I term working to
compensate for long term errors, but on the ground, or in your hand (without props on of course) it
doesn’t allow the I term to move the multicopter to compensate for the error.
A tuning video can be found here:
http://www.youtube.com/watch?v=YNzqTGEl2xQ