This is a discussion re the ArduCopter-3.1 AutoTune feature.  A place for people to report successes and failures, ask questions and get answers.

The AutoTune wiki page is here.


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tail servo is 12ms 5.7kg in my understanding it is an overkill for 11x47 prop. but I like to be on the safe side. 

btw, stock settings are just fine 0 bouncing and very responsive in stab mode. 

I've run autotune successfully on two different (but very similar) tricopters and it worked fine.

It completed in something like 4 minutes with me re-positioning several times in the middle.

I'd check to make sure your vibrations are not too high.

If you post the logs here I can have a look at them for you and if a axis finished I can tell you what to put in to your pids to speed up the process next time,

oh, it was almost 2 weeks ago, since than I have flown with stock PIDs almost every day 2 batt packs at a time, I will try this weekend after I rebuild it.  was having too much fun last night with my cousin mid aired near the tree, than into the tree than onto a concrete :) dt750 waisted, good thing I have a spare one, but my CF+balsa dowel arms held really good after falling from the top brunches of a tree onto a concrete not a single crack! 

Is there a way to guess starting pids from mass and size ?

Hi Bravojul,

The only thing I am pretty confident adjusting for is cell count. I find that changing all base pids, that is Rate and Accel PID's by "Old cell count"/"New cell count" works well.

As for size, there are too many factors.

Generally the defaults are good starting points but if you see or hear any wobble in stablize, then drop the Rate pids by 30%, and if you see or hear any ocilation in Alt hold drop the Accel PID by 30%. Then do Autotune.

AT Claims another...

Ok, so the story is that I was trying AT on my HEX tonight (first attempt). I just upgraded to 3.1.1 and made sure that everything was what it needed to be in MP just before flight.

Winds were light (between 5-10) so the copter drifted just a bit when a gust would come... I re-positioned the HEX when I needed to and the HEX would resume it's tuning. However, I never got the process to complete during the flight (got out of the roll, and started pitch) so I landed and swapped batteries. 

Now this is where I may have gone wrong... I reset all switches to stabilize (no AT) and noticed a very high wobble just prior to take off. Once airborne the HEX stabilized so I thought nothing of it. I got up to altitude with no incident and started Alt hold, and then AT (waiting for about 2-5 sec between). It started it's roll process and I started noticing something strange at this point. The radio that I have has an external voltage meter and as the HEX would roll to one side (in a heavy roll) the voltage alarm would bleep but as soon as the HEX leveled it would stop. It did this only during very heavy rolls, but I know that the battery could handle the current draw so again I let it go on (I know I should have stopped...). Anyway, it made it to the pitch portion of the process and made about 4 (or so) pitch tunes (heavy pitches) and the radio would beep like on the roll. Before I could say enough was enough and land the HEX tried to pitch one more time to the aft, only this time it stood almost vertical loosing all lifting force and crashed to the ground before I could switch back to stabilize. I have looked at the logs (luckily I had all turned on... or maybe unlucky, not sure) and I see no obvious power issues during the flight. I also see no vibe issues except just prior to crash. Could someone smarter than me take a look at the logs to see if they see anything?

If no one sees anything I may attempt another flight as soon as I get the props replaced... 

Also, can anyone quickly tell me how to go back to "factory" setting on the PID's so that I can start from scratch as I think the PID's that I have stored now are WAY out?

Thanks for everyone's time!


Hi everyone,

I perform this auto tune but after 3 mins it goes down (land on its own). Good thing is that it's already tuned up. My battery fully charge and fresh. Is it normal that after the tune it will land, if not what cause this problem?

I attached herewith my flight log so someone can take look.



    Resetting to factory defaults is done by going to the MP's terminal window, setup, reset, Y.

    I'm not much help when it comes to the cause of the crashes.  I believe the issues (mostly due to ESC sync) have raised the priority on getting "smart ESCs" out there.  Maybe that will allow us to catch some mechanical issues before they bring the copter down.


     Maybe this is the wrong log?  In this log the copter never gets above 60cm.

Successful auto tune today in a light breeze. Very impressive! Thanks for this feature!

Ops my mistake. here it is hope I pulled out the right one this time.:)

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