I experienced a very stange problem tonight and rather worrying.

GL500E Controller
aircraft firmware: V.01.05.0600
DJI Go4 : 01.04.01.00 (Updated Today)
Lightbridge On
Controller set to: 2.4GHz & Custom Ch

The P4 was 1900 meters from home point (approx to within 100meters) when suddendly it appeared that the P4 was stopped and didnt want to respond to any control.  The aircraft showed as connected and the screen preview appeared to be fine.  It did not take place during a warning, or symptoms of connection loss that a warning might be likely, it was as though it hit a geofence and just didnt want to go any further or back. I tried putting it into sport and then atti mode, but nothing responded.  I initiated a return to home as a last resort and still the distance from home never changed. (I cant remember if i could pan normally sadly, but I think I would have tried that) I realised that the app may just have crashed.  So I switched the controller off.  After switching it back on and then connecting to the P4 the bird was now only 700 meters away on a return to home.

Now things get a bit strange!

I logged onto air data to check the flight data and its wrong.  Alot of the flight data isnt even in the records!  Same when i review the flight on the controller and DJI Go.  Both say furthest home disance was 954 meters and  clearly - I know different.  Not only that, the flight records shows takeoff battery at 71%, but I know for a fact that at takeoff the battery was fully charged and showed 99%.  On top of that, the total flight distance is recorded as 968 meters, which is ridiculous!

This is a link to the Air Data Records
http://bit.ly/AirDataLinkOne


Thinking that the .Dat files may hold different I have uploaded direcct from the P4P the dat files and uploaded those too to Air Data and that tells a different story.
http://bit.ly/AirDataDatFileUpload

Flight distance  = Yes I agree with the data
air duration = no, 2 minutes in the air is wildly Inaccurate
signal score  = 100%

I conclude, the P4P dat file contained the correct distance data, but some incorrect data, but the Go4 App and corresponding flight record did not contain any correct data.

WTF?

Please provide the .DAT via Dropbox, GoogleDrive or similar.

BudWalker Posted at 3-13 17:17
Please provide the .DAT via Dropbox, GoogleDrive or similar.

dats

CharlesWhiteman Posted at 3-13 21:48
dats

I looked at FLY437. It is consistent with your description with the exception that the AC was unresponsive to control inputs.

When the AC was furthest from the HP (green plot) the pitch response (blue plot) to elevator input (red plot) was normal. Also note the light purple back ground which denotes the AC being in GoHome mode.

From your description you commanded the GoHome and can be seen in the eventLog stream
364.805 :   22219 [L-RC]rc cmd:STD_GO_HOME
about 40 secs later the AC received a cancel RTH command - probably you didn't know the AC was returning and pressed the RTH button.
405.205 :   24239 [L-RC]rc cmd:STD_EXIT_GOHOME_OR_LANDING
about 55 secs later the RC uplink connection was lost because the controller had been switched off
459.885 :   26973 [L-FLYMODE][Ctrl<6>] REQ_RC_LOST NAVI_GO_HOME ctrl_navi_go_home

Hi Budwalker, thank you for looking into this and the analysis is interesting. Are you able to glean any reason as to the loss of control?

You are right that I cancelled the RTH, as I observed that the P4P wasn't moving, according to the controller screen.  I switched over to sport and atti mode and then back to p-mode and I think it was at around that point that I rebooted the controller; which in doing so would have initiated an RTH.

I have been wondering whether a "factory reset" of the controller might be in order?  Or, could it be an issue in DJI GO4 perhaps.

The Airdata records also show the following responces that I have never seen before:

H

07m 08s

116.1 ft

1,322 m

Warning

[url=]Not Enough Force/ESC Error (repeated 2 times)[/url]

05m 51s

102.4 ft

1,919 m

[url=]80% Battery at maximum distance[/url]

CharlesWhiteman Posted at 3-14 09:24
Hi Budwalker, thank you for looking into this and the analysis is interesting. Are you able to glean any reason as to the loss of control?

You are right that I cancelled the RTH, as I observed that the P4P wasn't moving, according to the controller screen.  I switched over to sport and atti mode and then back to p-mode and I think it was at around that point that I rebooted the controller; which in doing so would have initiated an RTH.

Except for when the RC was rebooted control was never lost. I.e. the Uplink from RC to AC wasn't lost. I'm guessing that the downlink from AC to RC may have been lost and that just looked like you didn't have any control.

would you have any idea of the log messages:

This i've never come across before!

H

07m 08s

116.1 ft

1,322 m

Warning

[url=]Not Enough Force/ESC Error (repeated 2 times)[/url]

I cant find anything in the manual about this and it doesnt appear to relate to maximum distance settings

05m 51s

102.4 ft

1,919 m

[url=]80% Battery at maximum distance[/url]

CharlesWhiteman Posted at 3-14 12:35
would you have any idea of the log messages:

This i've never come across before!

I suspect the motor obstruction message is just a false positive. Detecting a motor obstruction is done using motor speed, current and probably some other parameters. It's not perfect. In this case it occurred when the P4P+ made the switch to ATTI and then max elevator and max throttle were applied.


The battery had 80% left when that message was issued.