Pos Rate PID controller

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Pos Rate PID Tuning

The Pos Rate PID controller takes the commanded speed output from the Pos PI controller and commands an attitude in order to maintain the position hold location. This PID controller should be tuned before adjusting the Pos PI controller.

The Pos Rate PID settings control how the attitude of the multirotor is changed in order to move towards the desired hold location.

The speed of movement is controlled by the Pos PI controller, while the attitude of the multirotor is controlled by Pos Rate.

When the multirotor is within the defined distance of the hold location or waypoint (set by GPS_WP_RADIUS in config.h) the Pos Rate PID is used, when further away from the location the Nav Rate PID is used to return to within the defined waypoint radius.

  • To tune the Pos Rate PID, initially set P, I and D values to 0.
  • Gradually increase P until the multirotor begins to position hold with some drift.
  • Gradually increase D until the multirotor responds more quickly to undesired changes in attitude caused by the wind. If this value is set too high you will see oscillations or sudden jerking in pitch and roll motion.
  • If needed, gradually increase I value to allow the PID controller to compensate for long lasting error, ie if it is being blown by the wind.