Involuntary yaw

[joe_c]

Hi all

Didn't really want my first post to be a request for help but...

I noticed the during my past couple of flights that my mavic seems to put a bit of left and sometimes right yaw (at a guess I would say about 10 degrees) on despite my inputting no yaw on the controller.

I have tried flying it multiple times in different wind conditions and it does not matter which direction or wind conditions I fly it in, this little bit of yaw seems to crop up. It seems random as to whether it is left or right and like I mentioned before does not seems to be linked to wind direction (flew it in all directions with a consistent right yaw.

I am not that experienced in these things so any help would be great.

Thanks all

J

 

[4wd]

The first thing to try would be calibrate controller.
It can be rather tricky though.
It is very easy to be a couple of degrees turned to one side which is barely noticeable until you have travelled some distance.

 

[BudWalker]

Hi all

Didn't really want my first post to be a request for help but...

I noticed the during my past couple of flights that my mavic seems to put a bit of left and sometimes right yaw (at a guess I would say about 10 degrees) on despite my inputting no yaw on the controller.

I have tried flying it multiple times in different wind conditions and it does not matter which direction or wind conditions I fly it in, this little bit of yaw seems to crop up. It seems random as to whether it is left or right and like I mentioned before does not seems to be linked to wind direction (flew it in all directions with a consistent right yaw.

I am not that experienced in these things so any help would be great.

Thanks all

J

Does this happen immediately after launch? If so, I have a theory. I would need the .DAT file to check it out. Look here to see how to retrieve the .DAT. It'll be large so you would need to Dropbox or GoogleDrive it and post a link.

 

[joe_c]

Dropbox - ExportCSV_2017-08-25_[14-29-11].csv

 

[BudWalker]

Dropbox - ExportCSV_2017-08-25_[14-29-11].csv

Sorry, this file doesn't provide the necessary data. The .DAT file is on the Mavic itself. Look here to see how to retrieve it.

 

[joe_c]

Sorry, this file doesn't provide the necessary data. The .DAT file is on the Mavic itself. Look here to see how to retrieve it.

Sorry mate, having issues downloading that now. No files show on the Sd card at all, I will keep trying

 

[joe_c]

Ah this might create a bit of an issue Access Flight Data after firmaware up data to v01.03.1000

Access Flight Data after firmaware up data to v01.03.1000

Budwalker did your theory have a fix I could try anyway?

Thanks

 

[BudWalker]

Ah this might create a bit of an issue Access Flight Data after firmaware up data to v01.03.1000

Access Flight Data after firmaware up data to v01.03.1000

Budwalker did your theory have a fix I could try anyway?

Thanks

Yes. My theory is that the yaw drift can occur if launch occurs before GPS is fully acquired. When GPS is acquired the geodeclination is determined and then the Yaw is adjusted to be based on true north. In a sense it's a Yaw adjustment, not a Yaw drift. So, the necessary conditions are that 1) it occurs immediately after lauinch, and 2) GPS is not fully acquired at launch.

BTW, see my post in
Access Flight Data after firmaware up data to v01.03.1000
DJI says this will be fixed.

 

[joe_c]

Thanks Budwalker, I will try that out when I'm next out. And thanks for the update on the flight records

 

[BudWalker]

Thanks Budwalker, I will try that out when I'm next out. And thanks for the update on the flight records

OK. If you think this is a possibility you could provide the .txt for one of those flights. That will at least tell us if the right conditions exist for this to happen. The .DAT would be required to know if it actually happens.

The best way to know if GPS has been acquired is to look at the GPS bar graph display on the controller. You want to see 4 or 5 bars.

 

[joe_c]

Thanks I will check that, I'll be honest I've only ever usually waiter for it to tell me it has gps and on rare occasions I've not waited for that before take off, I've just took it off and hovered it on visual (not ideal I know) until gps has come online.

I can't see any other files on the sd card other than pictures. I'm accessing the card using a mac via a USB into the drone but I have tried taking the sd card out as well. Strange.. unless I have missed something?

 

[JeepDSL]

The .DAT files aren't on your removable SD card; they're on an SD card built into the Mavic. You need to connect your Mavic to a PC and use Assistant 2 to retrieve the files.

 

[joe_c]

The .DAT files aren't on your removable SD card; they're on an SD card built into the Mavic. You need to connect your Mavic to a PC and use Assistant 2 to retrieve the files.

Ah ok fair enough, thanks for clearing that up, I was mega confused. assistant 2 is not working atm because I'm on the latest firmware then so I can't get them off just yet.

Thanks for the advice

 

[BudWalker]

Thanks I will check that, I'll be honest I've only ever usually waiter for it to tell me it has gps and on rare occasions I've not waited for that before take off, I've just took it off and hovered it on visual (not ideal I know) until gps has come online.

I can't see any other files on the sd card other than pictures. I'm accessing the card using a mac via a USB into the drone but I have tried taking the sd card out as well. Strange.. unless I have missed something?

The .txt file is on the tablet. Look here
DJI Flight Log Viewer
for instructions on retrieving the .txt.
You can upload the .txt to that site and provide the link that it produces and I can then use that to get the .txt file.
You can also attach it directly to a post in this thread

From your description it sounds like maybe this is the cause of the Yaw adjustment(drift).

 

[gnirtS]

Is this actual verified yaw OR is it possibly the gimbal moving the camera slightly?
Both can appear on the screen as the same thing.

 

[BudWalker]

Is this actual verified yaw OR is it possibly the gimbal moving the camera slightly?
Both can appear on the screen as the same thing.

That's a good question. The effect I was talking about would be a Yaw adjustment in the first 5 or 10 seconds. If it were the gimbal moving about then, presumably, it won't be restricted to the first 5 or 10 seconds.

 

[luiz eduardo ribeiro]

I think you are right. If I launch indoors without GPS signal it stays locked and do not yaw. Outdoors it will usually yaw (I can see the aircraft changing direction) for a while until it is higher, with more sats and perhaps less compass interference from the ground objects.

 

[gnirtS]

Mine yaws but seemingly *only* at altitude. Not specific if its left or right - it varies. Some flights not at all. Its not wind related or controller calibration related (.dat files show no inputs).
Ive tried swapping to new props etc but same thing.
Im still not 100% certain if its yaw or a gimbal drift though. As it only happens at altitude i cant SEE the drone well enough to just a slow yaw.

 

[BudWalker]

Mine yaws but seemingly *only* at altitude. Not specific if its left or right - it varies. Some flights not at all. Its not wind related or controller calibration related (.dat files show no inputs).
Ive tried swapping to new props etc but same thing.
Im still not 100% certain if its yaw or a gimbal drift though. As it only happens at altitude i cant SEE the drone well enough to just a slow yaw.

I'm assuming that Yaw from the .DAT doesn't change. You could also check totlalGyroZ which is an integration of gyroZ. If the FC is thinking that Yaw is incorrect and needs adjusting then it will hold the Yaw value constant and rotate the AC. So Yaw won't change, but totalGyroZ will change.

 

[gnirtS]

Im going to do a few more controlled tests if it ever stops raining. The yaw (if it is yaw) is very slight and doesnt always occur so its hard to see. On a normal flight its not that often hovering in one space long enough for me to notice either.

Ive had this "issue" since day one, through 3 firmware upgrades and multiple recalibrations of all the systems. Its a minor thing though and took me ages to notice it.