This article provides an overview of how to tune various Copter parameters.
I am a lifelong car enthusiast, and have worked with numerous shops on different car projects. I can confidently say that APM tuned receives my highest recommendation. Shop manager Ben took the time to brainstorm with me on which aftermarket parts and tune would best deliver a greatly improved but uncompromised car (Audi B8.5 S4). APM 2.5 w/3.1.5 won't start Auto-Tuning, Mission Planner shows enabled but quadcopter won't twitch. Title says it all. This is my first major 'unconquerable' task. This section of Mission Planner, invoked by the Menu item Config/Tuning at the top of Mission Planner, has several subsections. The subsection are where you configure the parameters that control how your auto pilot controls your vehicle. Tuning refers to adjusting parameters in the control loops so your vehicle behaves the way you desire. AutoTune attempts to automatically tune the Stabilize P, Rate P and D, and maximum rotational accelerations to provide the highest response without significant overshoot. Copter needs to be “basically” flyable in AltHold mode before attempting to use AutoTune as the feature needs to be able to “twitch” the copter in the roll and pitch axis. I had control issues w/ the previous auto-tune results, and had manually tuned them up to about.09 P&I,.0015 for D. Now autotune gives me great results. (This is comparing 3.6 auto-tune to 4.0 w/ the harmonic notch And I believe I had my D term filters at about 40 for the last tune.
Mission Planner Auto Tuning Reviews
Overview
The default PID gains are meant forthe 3DR IRIS although they work on a wide variety of frames. Still, to get optimalperformance you may need to adjust them which can be done through theMission Planner's Config/Tuning Copter Pids screen. The screenshot below shows the most important parameters for Roll/Pitch (yellow),Yaw (orange), :ref:`Altitude hold <altholdmode>` (green),:ref:`Loiter <loiter-mode>` (pink) and:ref:`Waypoint navigation <auto-mode>`(blue).
The most important parameter to get right is the Rate Roll P (and bydefault Rate Pitch P is locked to the same value) as discussed:ref:`here <ac_rollpitchtuning>`.
Normally it's best to start by tuning the Rate Roll/Pitch P in Stabilizemode then move onto tuning altitude hold in AltHold mode, then Loiter(which often needs no tuning) and finally the waypoint navigationperformance in Auto mode.
Note
Dave C's AC2.8.1 tuning guidehas good information for tuning for rate roll and pitch but altitude hold,Loiter and navigation has changed dramatically since AC2.8.1 so thosesections are no longer valid.
Roll/Pitch tuning
The Stabilize Roll/Pitch and Rate Roll/Pitch parameters, highlighted inyellow in the screen shot above control the roll pitch response.
The Rate parameters which convert the desired rotation rate into a motoroutput are the most important. The :ref:`Rate Roll and Pitch P tuning page <ac_rollpitchtuning>` has themost information on tuning them.
The Stabilize Roll/Pitch P converts the desired angle into a desiredrotation rate which is then fed to the Rate controller.
- A higher value will make the copter more responsive to roll/pitchinputs, a lower value will make it smoother
- If set too high, the copter will oscillate on the roll and/or pitchaxis
- If set too low the copter will become sluggish to inputs
More information on tuning the roll and pitch can be found on the:ref:`Stabilize mode page's Tuning section <stabilize-mode_tuning>`.
An objective view of the overall Roll and Pitch performance can be seenby graphing the :ref:`dataflash log's <common-downloading-and-analyzing-data-logs-in-mission-planner>`ATT message's Roll-In vs Roll and Pitch-In vs Pitch. The 'Roll' (i.e.actual roll) should closely follow the 'Roll-In' while in Stabilize orAltHold modes. Pitch should similarly closely follow Pitch-In.
Alternatively you may wish to try tuning both the rate and stabilize(i.e. angular) parameters using the :ref:`AutoTune feature <autotune>`.
Yaw tuning
The Stabilize Yaw and Rate Yaw parameters, highlighted in orange in thescreen shot above control the yaw response. It's rare that the yawrequires much tuning.
Similar to roll and pitch if either Stabilize Yaw P or Rate Yaw P is toohigh the copter's heading will oscillate. If they are too low the coptermay be unable to maintain it's heading.
As mentioned on the :ref:`Stabilize mode's tuning section <stabilize-mode_tuning>`,the ACRO_YAW_P parameter controls how quickly copter rotates based ona pilot’s yaw input. The default of 4.5 commands a 200 deg/sec rate ofrotation when the yaw stick is held fully left or right. Higher valueswill make it rotate more quickly.
Altitude Tuning
3utools comment ca marche logiciel gratuit. The Altitude hold related tuning parameters are highlighted in green inthe screen shot above.
The Altitude Hold P is used to convert the altitude error (thedifference between the desired altitude and the actual altitude) to adesired climb or descent rate. A higher rate will make it moreaggressively attempt to maintain it's altitude but if set too high leadsto a jerky throttle response.
The Throttle Rate (which normally requires no tuning) converts thedesired climb or descent rate into a desired acceleration up or down.
The Throttle Accel PID gains convert the acceleration error (i.e thedifference between the desired acceleration and the actual acceleration)into a motor output. The 1:2 ratio of P to I (i.e. I is twice the sizeof P) should be maintained if you modify these parameters. These valuesshould never be increased but for very powerful copters you may getbetter response by reducing both by 50% (i.e P to 0.5, I to 1.0).
See the :ref:`Altitude Hold flight mode page <altholdmode>` for more information.
Loiter Tuning
Generally if Roll and Pitch are tuned correctly, the:ref:`GPS <common-diagnosing-problems-using-logs_gps_glitches>`and :ref:`compass <common-diagnosing-problems-using-logs_compass_interference>`are set-up and performing well and :ref:`vibration levels <common-diagnosing-problems-using-logs_vibrations>`are acceptable, Loiter does not require much tuning but please see the:ref:`Loiter Mode <loiter-mode_tuning>` page for more details on tunableparameters including the horizontal speed.
In-flight tuning
A single parameter's value can be tuned in flight using thetransmitter's Ch6 tuning knob. A specific example for tuning the RateRoll/Pitch P values can be found on the :ref:`Rate Roll and Pitch P tuning wiki page <ac_rollpitchtuning_in-flight_tuning>`.Please see the Ch6 Opt drop-down on the Mission Planner'sConfig/Tuning Copter Pids's screen for a full list of parametersthat can be tuned.
Mission Planner Autotune
After setting the Ch6 Opt value, the Min and Max should also be set toreasonable values (i.e. non-zero and also not unreasonably high) andthen the 'Refresh screen' button should be pushed by tuning the Ch6 knobto ensure that the parameter is updating correctly.
Filter tuning
Copters are often affected by vibration and tuning the various software filters available is critical to achieving an overall tune.A guide on tuning the various notch filters available can be found on the :ref:`Notch Filtering wiki page <common-imu-notch-filtering>`.
Mission Planner Auto Tune
Video introduction to PIDs
PIDs (Proportional - Integral - Derivative) are the method used by ourfirmware to continuously stabilize the vehicle
- Proportional = Immediate Correction: The further off you are thebigger the correction you make.
- Integral = Over time or steady state correction: If we are failing tomake progress add additional correction.
- Derivative = Take it Easy correction: Is the correction going tofast? if it is slow it down (dampen) it a bit to avoid overshoot.