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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I hope I'm posting this in the right place.

I rebuilt my 2013 3DR quad this week and am trying to get it back into service.  It is now all running OK so I attempted auto tune today.  It flies OK but is a bit twitchy in loiter in a breeze.

Question is: Is there any way to speed up the autotune process so it completes in less than about 10 minutes.  I keep running out of battery, going into failsafe and landing.  In three tries I got through roll once and it was just starting pitch. The other two tries it never got through roll.  Perhaps manually adjusting the PIDs to get them closer to where they are likely to end up so autotune has an easier time converging on the best?

My quad has 880 motors and 11 inch props.  I fly at 6300' base elevation.  I have loaded the latest mission planner and firmware into the pixhawk.  External GPS and compass on a stalk out the top.  5000 mAH battery that is well used (new ones on the way).   GoPro clone on a pitch mount under the batteries - and that mount is pretty stiff so I don't think it's wobbling.

Jim

Yes, you can do one axe at a time: Roll, change batt, pitch, change batt, and yaw, you have to go to full param list and change autotune all three axes for roll axe, then pitch alone and last yaw alone, looks here: http://ardupilot.org/copter/docs/autotune.html?highlight=autotune

Jim White said:

I hope I'm posting this in the right place.

I rebuilt my 2013 3DR quad this week and am trying to get it back into service.  It is now all running OK so I attempted auto tune today.  It flies OK but is a bit twitchy in loiter in a breeze.

Question is: Is there any way to speed up the autotune process so it completes in less than about 10 minutes.  I keep running out of battery, going into failsafe and landing.  In three tries I got through roll once and it was just starting pitch. The other two tries it never got through roll.  Perhaps manually adjusting the PIDs to get them closer to where they are likely to end up so autotune has an easier time converging on the best?

My quad has 880 motors and 11 inch props.  I fly at 6300' base elevation.  I have loaded the latest mission planner and firmware into the pixhawk.  External GPS and compass on a stalk out the top.  5000 mAH battery that is well used (new ones on the way).   GoPro clone on a pitch mount under the batteries - and that mount is pretty stiff so I don't think it's wobbling.

Jim

Have a question about filter settings.  In the wiki, it states to use a 10hz filter instead of 20 on large copters.  What would you consider large.  Obviously a 680mm is not, but would a 960mm X8 swinging 18" props fall into that category?  I've never tried changing the filter so I'm off to do an auto tune on a 1300mm X8 swinging 2880's.  BTW, this isn't 3.1, but 3.4rc2 firmware.

I would say anything bigger than 15" props would be getting there but it also depends on whether or not you have ESC braking available.

Let us know how you go!!

Randy did a great job extending the autotune page in the Wiki!!

No esc braking on any of my units.  So my 18" 960 X8 and HEX may tune better by lowering the filter rate more likely or less because of the lack of braking?  Well, I should get the big rig out and auto tune it before the heat hits.  Thanks for the reply!

Bigger the rig, the crazier to autotune?  Well, setting the filter to 10hz and aggr to .1 worked really well on the 960mm X8 and the 960mm HEX.  Not so good with my 1300mm X8.  Started out fine, but after about 6min the roll inputs started getting really excessive.  Instead of rolling one way and stopping it would roll extreme right and then roll extreme left in one motion.  After a minute or two of that I realized it was probably going to roll right over lol!  I've never seen this before.  Think I've set the aggr too high at .1.  I'll go back out tomorrow and try again.  Specs:

-firmware 3.4rc5

-1300mm X8

-Tmotor U8 170kv motors

-Foxtech 2880 supreme props

-8s44ah 

-AUW 16kg

Dataflash log:

https://www.dropbox.com/s/emer3e1hsamix6w/2016-09-20%2018-37-27.bin...



Shaun Bell

Hi Shaun,

I will take a look tonight.

Thanks Leonard!  I'm your guy for testing big copters and AT lol!

Hi Shaun,

Could you do a 4 minute flight with the Log Bit Mask of : 786429

Could you make sure you have a fast SD card in the pixhawk. (like as fast as you can get)

Just a Stabilize for the first minute

Alt Hold for the second minute

Loiter for the third minute

and a minute of flying around.

I am seeing some things that look like noise and I am trying to track it down.

Thanks,

Leonard

Ok, now I know why you specified 4 minutes.  It takes forever to download.  I'll get it up pretty quick  I also did another AT at .075 and .085.  I'll post links to those as well if you want them

Hi Leonard,

Here's the link:

https://www.dropbox.com/s/tnluc96109zprzy/2016-09-22%2017-52-09.bin...

Tuning is pretty crazy.  A lot of pitching in forward flight.  Enough to almost send it to the ground but it recovered later in the loiter part of the flight. Maybe I'll bring the I up before I do any more AT's.  When I get back I'll post the two Autotunes after this flight.

Thanks!

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