Heavy Y6 adventure thru 3.4 RC with AutoTune

I read through this start to finish. I will answer some questions quickly.

First up MOT_HOVER_ LEARN. For this to learn your new hover throttle the copter has to be in a hover for 10 to 20 seconds. If the copter is moving up and down it won’t update the hover throttle setting. So if you take off after changing the load for the first time and switch into Alt_Hold you will probably need to recenter your throttle stick to stop the copter climbing. Also if your Accel I max is very small you will find your copter will sink (I think you have solved this problem already).

Just set your Accel I max to a big number, it only really matters if it is too small. This is something we will clean up in the next release.

Ok, the next issue is MOT_THST_EXPO. This is similar to what you are used to seeing with stick expo but designed to linearise the thrust of the esc/motor/prop to the pwm input. The effect of this is the output to the esc’s increase quickly at low ranges and slowly in the high ranges. So on an over powered copter the hover throttle will look very low. This is something you need to set based on thrust measurements but I have found 0.65 is a good number for most copters including all coax setups and 0.75 is good for very large props on quad hex and octo air frames.

A word on parameter translations and variables in mission planner Extended tuning screens. Some numbers have been scaled in mission planner in that screen. I always use the direct parameter screen so I am not sure which ones are scaled. As we clean up the parameters and move to SI units this should all disappear.

Alt Hold. I have found on over powered copters Alt Hold can benefit from halving the Accel P and I values and both the Pos and Vel Z values.

Hot Motors: When your tune is aggressive your motors will heat up more. This is especially true when using ESC breaking. From one flight to another you may find rougher wind results in higher temperatures. If your batteries are on loose and you start getting some slight oscillation your temperatures will go up.

ESC Calibration: a difference of 4 not a big difference. If you did it using the manual calibration that is probably as close to correct as you can get it.

Ok, Autotune.

Autotune always starts from your current PIDs. It does not start from a default set. If autotune takes a long time it is often because you are tuning in poor conditions or have made a change that results in a very different tune.

Copter leaning to one side more than the other. This is caused by an offset CG (not your problem), side ways movement through the air or side wind (more likely your problem), different ESC setups on different arms (probably not your problem).

The way I ensure I don’t have wind loading effects messing up my autotune is to always place the axis being tune 90 degrees to the wind. So I let the copter drift while it is tuning. When I decide I have to bring it back I only use yaw and the axis I am not tuning. So while tuning roll, I would yaw the copter so it is facing directly away from me and use pitch to bring it back. While tuning pitch I will use yaw to put the copter directly side on to me and use roll to bring it back.

Tuning in rough air or having wind effected tunes can result in very significant variations in Autotune. This is probably why your autotune numbers vary so much.

Ok, I think I have covered most of the outstanding questions. If you would like some help with your autotune results then let me know exactly what logs to look at and what issues you are seeing. I know you have had many autotunes in this thread but you have also changed many things and fixed many problems so I am not sure where you are up to.

Hope this has been helpful!!



Thank you very much for time and answers…maybe we can come back for a few latter.
Yeah its long thread…sometimes is good as reminder when i did what…
I guess most of my questions and doubts are answered…
I didn’t answer before bcs. i wanted fresh results ,so today i made…You guess what?
Another…MFAT…in fact two of them!

Autotune 01.11.16


Today it was a nice day,so i decided to give AT another try…
Considering advices about my setup i changed antivibration mount completely,and remove all suspicious parts
Here are pictures:

also i set
Throttle Accel I MAX to 80



ATCRAT_RLL_P = 0,120375
ATCRAT_RLL_I = 0,120375
ATCRAT_RLL_D = 0,0050528

ATCRAT_PIT_P = 0,1645769
ATCRAT_PIT_I = 0,1645769
ATCRAT_PIT_D = 0,007028

At first when i try to invoke autotune,after entering alt hold followed by AT switch on ch.7 nothing happened…?
After landing and disarm/arm >>>AT started…Roll first…everything seems fine…
After landing and saving new parameters i thought i changed AT to Pitch tuning,but i didn’t press write button so Roll tune started again…that was fortune bcs in that SECOND tune,copter was autotunig somehow more crisp and did exactly all the steps properly,immediately i could noticed difference…
Afterwards i started Pitch tune…it looked ok,but after first try i ended with some unrealistic values of
Only after second attempt of Pitch autotune right after,it tuned well

Here are the new PIDS

My LiPos were empty,so i will do test flight another day,but it looks promising…
7kg Y6 is crisp and agile again…

P.S.Few times i’ve heard msg;inconsistent compasses …Compass learn was ON

Please share your warnings,thoughts,ideas and suggestions how to make it better…Thank you

My motors are medium hot again…when i test lower PIDs afterwards will try with BLHeli ESC timing medium-low settings instead medium…

when i look to my results from complete AT of 17.09.16 there is similarities,not much diference

Tomorrow i will start with PIDs 15% lower from today’s high results

That’s it…15% lower from AutoTune is somehow how i want it,crisp and responsive,but humble…
Loiter is perfect but AltHold still lose height at the end of fast forward flight if throttle is not added…
log from short test between rain;


what do you think,is it too high?

Hi Emin,

The problem with your alt hold is the classic baro error caused by air moving over the aircraft and causing the pressure reading to drop. This results in the baro reading 1.5m higher than the predicted altitude. This causes the drop in altitude over the next few seconds.

I don’t have a fix for this without a lidar or better aerodynamic design of the static port.

another flight from today. 09.11.16…3.4.2 rc2…
alt hold correcting P as well…i dont know what i was soposed to see…?

I solved altitude lose covering the FC with a bowl


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Hi Emin,

I am building something similar, Problem is I have to have it up and running perfectly in 2 weeks, so I cannot have any more oooops moments. (I already had 3)
AUW is planned to under 4.5kg, Y6 Frame, Multistar 4108 motors, 17x5.5 props, 4S 15000mAh, length of the copter is 75cm.
Stabilized flew OK last time, but as soon as I switched to Alt hold copter made 3 rolls left-right-left and hit the ground.
1.) Usually I never ask for PIDs as no 2 DIY builds are the same but this time I would like to ask you to send me the PIDs eventhough you have much bigger motors.Could you please?
2.) For testing and I started using a 3DR Y6 converted from X8. Funny thing is that the roll P=I=0.152 the picth P=I=0.236. Is that difference normal for a Y6 config?

Many thanks in advance!

Hi…pids are still same like in my last post…i must admit i didn’t fly it a lot over the winter…
Also,my Y6 is weird animal so i siriusly doubt that will help
Why don’t you try PIDs Randy suggested to me and start from there…
ATC_RAT_PIT_P = 0.155
ATC_RAT_PIT_I = 0.155
ATC_RAT_PIT_D = 0.0056

ATC_RAT_RLL_P = 0.155
ATC_RAT_RLL_I = 0.155
ATC_RAT_RLL_D = 0.0056

ATC_RAT_YAW_P = 0.62
ATC_RAT_YAW_I = 0.062

But if your ALT hold is wrong you can’t expect to autotune…
but as soon as I switched to Alt hold copter made 3 rolls left-right-left and hit the ground. this sounds like you started Autotune not alt hold…
Also,best thing would be to make your own post with logs from that flight and someone more experienced will be able to tell you exactly what’s wrong…also my post is very long and very few will notice your question…without logs no one can understand what is problem.
Are you using APM,Pixhawk or Pixhawk 2??Are you sure you have your ESC properly calibrated…what is model of your ESC,some of them can have problems with low KV motors and big props?Is your MOT_THST_HOVER set correctly?What is your LiPo?4S 15000mAh…is your C rating ok?etc.etc…