AC-3.1 autotune support discussion

Shaun Bell August 19, 2016 at 12:09pm

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.

Cala July 29, 2016 at 4:52pm

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

AutoTune — Copter documentation

Jim White July 29, 2016 at 2:42pm

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

T3

Thorsten June 16, 2016 at 7:36am

I am wondering what has the stronger negative influence on autotune - wind or some pilot input from time to time to bring the copter back. Not sure if possible but I guess it would help if autotune waits for 1 or 2 seconds after the pilot released the sticks because the copter is sometimes still drifting when autotune proceeds.

Developer

leonardthall > Thorsten June 19, 2016 at 4:26am

Hi Thorsten,

Yes, that can be a problem. My next major change to autotune will be to let it get started from Loiter. It would then hold position on it's own.

Cala June 15, 2016 at 2:44pm

I have a new build: a Robocat 270 with a Pixracer (AUAV) but I can't do autotune works, finally I try to manual tune, no wind and looks nice, cool Alt Hold like near Loiter, I try first with one axis (1) and nothing, only very short movements and then nothing, then I try with all axes (7) but the same thing, I controlled CG (not very easy on this little guy) mid thr is near 48 and althld works nice with stick on the middle; I'm shure that I missing some silly thing but I'm not figure what, someone can help me please?

Here my log:

https://www.dropbox.com/s/xzrmplqv6fcxs0e/failed%20autotune.BIN?dl=0

Dropbox - Link not found

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Developer

leonardthall > Cala June 15, 2016 at 4:47pm

Hi Cala,

The problem here is your rate noise. Could you please try something for me. Could you set

INS_ACCEL_FILTER to 10

ATC_RAT_RLL_FILT to 20
ATC_RAT_PIT_FILT to 20

ATC_RAT_YAW_FILT to 2.5

LOG_BITMASK to 196605

Be a little careful on your first take off as the filter changes may affect you tune.

Thanks!!
- Cala > leonardthall June 16, 2016 at 7:34am
  
  I try today, no wind, with this params but only change the copter become little movements more nervous
  
  https://www.dropbox.com/s/w9sbq4cebukovpl/5%2016-06-2016%2011-17-02...
  
  Dropbox - Link not found
  
  Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
- T3
  
  Thorsten > leonardthall June 16, 2016 at 12:16am
  
  Hi Leonard,
  
  I am also having some problems with autotune on a new overpowered copter and posted a log as well as some details at:
  
  http://discuss.ardupilot.org/t/autotune-failed-pixracer-overpowered...
  
  Since the vibrations are low on my copter I think it is not the best idea to lower the frequencies. Anyway one question what do you mean with rate noise?
  
  Thanks,
  
  Thorsten
  - T3
    
    Thorsten > Thorsten June 16, 2016 at 3:41am
    
    As posted at discuss.ardupilot.org I got a working pitch autotune after some tries. Too much wind now to run some more test...

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AC-3.1 autotune support discussion

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