A2 problems - very unstable bird

[kjetilpa]

I have several hundred flight with my Tarot T960 hexacopter using TMotors and a Naza-M V2 controller. Total weight is 6.5 kg. This combination works perfect.

But when using a DJI A2 flight controller on this bird it becomes very unstable. It is wiggling (dancing in the air) from side to side. I have tried basic gain settings between 100 to 210% with no success.

All software is updated to latest versions.


Any idea on how to solve this?

Kjetil

 

[SleepyC]

What are your gain settings, where is the IMU located and how well is everything balanced?

The A2 is very much more sensitive to vibrations and proper set up in the GUI. Make sure your CGI is correct (it's not where you put the IMG but where it is on your machine, so is your IMU above the CG in the center, and if so by how much)

List as much info as you can and we can try to help.

Also, you did update all the components of the A2 correct? This is a bit different from the Naza.

 

[kjetilpa]

Here are some images of the hexacopter setup with the A2 flight controller mounted + numerics related to CG.

SETUP
I am also using a DJI Lightbridge and a 3G GPS.

View attachment 25306

COMPASS
The distance from the CG (X) to the compass is -25 cm.

View attachment 25307

COMPASS
The distance from compass to CG (Y) is -6,5 cm
(This value is -5 cm in A2 assistant)

View attachment 25308

IMU
The distance from IMU to CG (Z) is -13 cm
(This value is -20 in A2 assistant)

The distance from IMU to CG (Y) is 0 cm

The distance from IMU to CG (X) is +5,5 cm
(This value is 4 cm in A2 assistant)

View attachment 25309

And some screenshots from the A2 assistant from the last flight

View attachment 25314

View attachment 25315
View attachment 25316
View attachment 25317

 

[SleepyC]

First I'd say move the IMU to the center. I know you can tell the GUI where it is, but I have never seen a rig fly properly with it elsewhere.
Also clean up your wires and components, believe it or not sloppy wires cause a lot of issues.

Clean and simple.

View attachment 25341

 

[hjls3]

[/QUOTE]
COMPASS
The distance from compass to CG (Y) is -6,5 cm
(This value is -5 cm in A2 assistant)
IMU
The distance from IMU to CG (Z) is -13 cm
(This value is -20 in A2 assistant)
The distance from IMU to CG (Y) is 0 cm
The distance from IMU to CG (X) is +5,5 cm
(This value is 4 cm in A2 assistant)
[/QUOTE]

why are your measurements different in assistant?

 

[kjetilpa]

I will correct this and do a testflight today,

Kjetil

 

[kjetilpa]

First I'd say move the IMU to the center. I know you can tell the GUI where it is, but I have never seen a rig fly properly with it elsewhere.
Also clean up your wires and components, believe it or not sloppy wires cause a lot of issues.

Clean and simple.

View attachment 25341

I will change to this placemend and try, Do you have any idea on what gain settings to use?

 

[SleepyC]

I will change to this placemend and try, Do you have any idea on what gain settings to use?

If you look at the back of the manual there are general gain settings for most of the DJI airframes and they list the weights in Grams. I usually pic the settings that are closest to my AUW and start there!

 

[MombasaFlash]

Here are some images of the hexacopter setup ....

I cannot say that I have had any significant issues with the A2, certainly no more than the WKM, and my IMU is never mounted central. Some folks seem to be able to get away with basic double-sided tape for mounting the IMU, I always use Kyosho Gel to help with isolating the IMU.

Your Basic gain settings look a bit high and the Attitude settings a bit low. Try starting with the recommended settings before venturing any changes.

And for God's sake clean up that bleeding 'orrible mess.