Spooky Action at a Distance

[gregw]

Well, the DAT I'm uploading now (2.5 hrs to go) will show 90% of the flight in P-mode. I switch to S-mode to get back to homepoint - but what should have been a straight line back looked like a drunkard trying to walk a line. When I got back to within the final minute or two, I'd switched back to P-mode, but the wild TBE was worse than ever. It settled just before landing - which I attributed to getting closer to the ground where VPS took over - but maybe it was the merging of the Yaw/magYaw as you described it.

I tell you one thing, if not for investigating this, or emergency need, I will not willingly switch back to to S-mode. How do we get DJI involved to get this addressed?

I think DJI really needs to look at your case more closely... Maybe you could email DJI support and point to post #31 above or start a new thread in the DJI Mavic forum with reference to the same post...

Maybe all the TBE issues are down to this one problem that DJI hasn't caught...

I just posted a link to #31 above to the long Mavic thread over at RCG asking Ken & Ed to escalate this up to DJI.. Hope this helps to solve all these TBE issues..

 

[Vlakvark]

My apologies, BudWalker, for not sending the .Dat files of my ToiletBowling incidents yet. When I try to open the files on my MP on DJI Assistant 2, installed on my Macbook Air, the little "death spiral" just goes round and round until the MP battery is dead!

Importantly, though, I have never flown in S mode yet, so, my TB events could not have been triggered by a mode change from P to S.

Meanwhile, I have done a thorough IMU- and Compass calibration and flown relatively far and high with Dji Go and Litchi and the MP has been perfectly stable!


Sent from my iPad using MavicPilots

 

[Ed Windham]

I have reported to engineering. We will see what they say. If we can get the owner to download the .DAT files to a hosting site like Dropbox that would be helpful

 

[Vlakvark]

I have reported to engineering. We will see what they say. If we can get the owner to download the .DAT files to a hosting site like Dropbox that would be helpful

I'm trying to download the .DAT files. As soon as I succeed I will make them available!
Sorry!

 

[erkme73]

I have reported to engineering. We will see what they say. If we can get the owner to download the .DAT files to a hosting site like Dropbox that would be helpful

@Ed Windham thanks for stepping in here. I am currently in middle TN where Internet is via 1mbps DSL. It took nearly 6 hours to upload the latest TBE DAT file to my Google Drive for @BudWalker. He has both the original DAT from which he's drawn his preliminary conclusions, and the link to yesterday's flight that had the worst TBE yet. He has offered to make both available to you on my behalf. He should be reaching out to you shortly.

Thanks to both of you.

 

[BudWalker]

I looked at the second flight provided by @erkme73 which was similar to the first flight. However, there was one significant difference. The magZ noise occurred for a short interval while not in Sport mode. During this interval both elevator and throttle were at a max resulting in a higher current.




From this and the first flight a better theory would be that the magZ noise is caused by a higher current resulting from either 1) throttle and elevator at max in normal mode, or 2) elevator at max in Sport mode.

Please understand this is just a theory that needs to be validated. It could change, or proven incorrect. In fact, trying to disprove it is the best way to gain more knowledge about these incidents. Obtaining the .DATs for those flights with TBE but without Sport mode would be particularly informative.

Still unanswered are
1) Does the magZ noise lead to the Yaw/magYaw separation,
2) Does the Yaw/magYaw separation cause TBE
3) Is the magZ noise particular to @erkme73's Mavic or does it occur with other Mavics. I can test this here when the weather clears.

 

[BudWalker]

My apologies, BudWalker, for not sending the .Dat files of my ToiletBowling incidents yet. When I try to open the files on my MP on DJI Assistant 2, installed on my Macbook Air, the little "death spiral" just goes round and round until the MP battery is dead!

Importantly, though, I have never flown in S mode yet, so, my TB events could not have been triggered by a mode change from P to S.

Meanwhile, I have done a thorough IMU- and Compass calibration and flown relatively far and high with Dji Go and Litchi and the MP has been perfectly stable!


Sent from my iPad using MavicPilots

I've heard of this happening with the PC version of DJI Assistant 2. I suggested to him that he make to install the USB driver that comes with DJI Assistant 2. Is there an equivalent suggestion for the Macbook Air? I suppose you could ask DJI support. It is their product and they should want it to work. However, they may not be keen on your intended purpose.

Changing to Sport is not the whole story. It would be good to have those flights where you encountered TBE.

 

[niclariv]

The big question then is - is this something that could be fixed with a firmware update or is this a hardware problem? And if so, is it really only a few Mavics or does it mean a bigger issue that will affect production?


Sent from my iPhone using MavicPilots

 

[Kilrah]

If it can add a data point, I flew today at full speed in Sport mode for several seconds back and forth to look at the max speed without any strange behavior. I could have a look whether there was any noise at that point if you point me to the software.

 

[generaltso]

Is the magZ noise particular to @erkme73's Mavic or does it occur with other Mavics.

I can pull the DATs from my atti mode flight if another data point would be helpful.

 

[Guest]

@Kilrah It's in it's in BudWalker's signatue:

Creator of DatCon an offline .DAT file converter - CsvView/DatCon
Creator of CsvView an offline app to visualize .DAT and .txt files - CsvView Introduction

 

[Kilrah]

Oh, didn't see he had now posted the Mavic version of DatCon, had checked yesterday - downloading now.

 

[BudWalker]

If it can add a data point, I flew today at full speed in Sport mode for several seconds back and forth to look at the max speed without any strange behavior. I could have a look whether there was any noise at that point if you point me to the software.

I also did a test flight using Sport mode at full throttle. The magZ noise had a range of 250. The magZ noise in @erkme73 's flight was 1600.

DatCon for the Mavic .DAT has been released. Check here first. CsvView for the Mavic .DAT should be released in a day or so. But, the current version will work if you first use the Mavic DatCon to produce the .csv and then load that into CsvView. CsvView will complain about missing columns; just ignore that. When the Mavic CsvView is released it will accept the Mavic .DAT directly and translate it internally using Mavic DatCon.

 

[Kilrah]

OK, for me it seems to be about 400.
Yaw and MagYaw are well matched at that time, but it's interesting to see that earlier in the flight they were quite separated by about 7° for a couple of minutes. I was adjusting the gains, so giving big stick inputs without letting it move much, so it likely never got a chance to get a meaningful GPS course... they converge again when I start moving a bit more again, but behavior was totally normal.

CSV attached if you want to have a look. And thanks for the tool, very intreesting to be able to check all of that!

 

[Sky Captain]

Dropbox - 2016-11-23 13_47_11.dat

I think thats it,

BudWalker and DJI, please analyze the incident from the OP

 

[BayouBill]

@Sky Captain - you have described to a Tee what happened to me. And several others. The consensus seems to be bad compass calibrations, and that the observed behavior is 'to be expected'. I've never had this happen with my Phantoms.

This flakey compass problem masquerading as GPS loss is a common DJI problem with Phantoms as well. The P3 forum is loaded with examples. I have experienced it many times with my P3P after calibrating in an open field with no metal for hundreds of feet. I had hoped it would be corrected in the Mavic. I have flown a little Bebop 2 in the same area many times with no hint of a problem.

 

[Sky Captain]

By the way, I flew today with no issues after doing a very careful IMU then compass calibration

 

[BudWalker]

Dropbox - 2016-11-23 13_47_11.dat

I think thats it,

BudWalker and DJI, please analyze the incident from the OP

That's not the right .DAT. The .DAT you want is on the Mavic itself, not the tablet.

To retrieve a Mavic .DAT file use DJI Assistant 2 and go to the Flight Record tab. After confirming that it's OK to put the Mavic in Flight Data mode a list containing the recent flights will appear. Select just the Flight Control File of the incident flight and then press Save To Local. Ultimately a file with a name something like DJI_ASSISTANT_EXPORT_FILE[2016-10-27 22-40-28].DAT will be created.

 

[Sky Captain]

assistant 2 is not able to get dat files off of my mavic, I uninstalled it then reinstalled it, still does not work.

 

[erkme73]

assistant 2 is not able to get dat files off of my mavic, I uninstalled it then reinstalled it, still does not work.

Make sure you're using a good quality USB cable. Also, some microUSB ends don't seat properly, and if there is any movement, it'll cause the PC not to see the Mavic. I had zero problems getting the DAT off of the MP when at home in FL, but trying it on another PC here on the road, I tried three different USB cables before it would show up.