90 + kph Mavic pro 2 flyaway

[Rubistorm]

Hi All,
A friend had a flyaway and the drone moved according to most of what we can determine over 90 KPH . DJI says wind gust . Which was on a day with surface winds about 10 KPH. Anybody able to help out here
here is link to dat file it is big 2. + GB unless a txt may be better ? Let me know, Sorry, new to this , not sure if even posting where it should be
Don Joyce Sept 1 Flight Log - Google Drive

Drone did execute a RTH , but we really would like to know what issue actually was....help ?

I have attached a txt file as well

Rubistorm,

 

[Rubistorm]

p.s. reviewing in airdata UAV indicated drone hit a top speed of 58.9 MPH and no stick input !

 

[Rubistorm]

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[Rubistorm]

13 MPH in a NNW direction

 

[Rubistorm]

sorry hit the key too quick, during the flyaway it was between 5 and 8 mph in a nne direction

 

[Meta4]

A friend had a flyaway and the drone moved according to most of what we can determine over 90 KPH . DJI says wind gust . Which was on a day with surface winds about 10 KPH.

The drone has been facing NW and flying NNE at less than 2 mph in cruise control mode (?).
At 12:01.3 it rotates to face SE, maintaining the slow speed in a NNE direction.
But at 12:06.2 the roll increases from <1° to 25° and the drone begins to accelerate, still flying sideways towards the NNE, reaching 58 mph at 12:17.5.
The drone was >600 feet away at the time and only 35 ft up.
It should have been impossibly not to notice any wind fast enough to blow the drone at that speed when the drone was so close.

Since the drone is flying sideways, the increasing roll angle is the equivalent an increasing pitch angle in forward flight.

The roll angle peaks at 36°at 12:23.6 and remains high until 12:44 when the drone rolls hard in the opposite direction.
RTH was initiated at 12:29.2 and the drone is then flying in RTH hands off.
It takes until 12:35.4 for the drone to adjust heading to point toward the home point and until 12:46.3 to reach the set RTH height of 130 ft.
Despite having no joystick input, the drone then descends to 109 feet and climbs back to RTH height again at 12:54.5.
It has slowed down to 7mph but accelerates again, reaching 39mph at 12:58.7 (with increased pitch and roll angles).
Speed stabilises at 24-25mph, still with abnormal pitch and roll angles.
This is approximately normal RTH hands-off speed.
At 13:07.1 the pilot cancels RTH and flies the drone home normally.

If this was the result of wind, the flyer should have noticed a wind so strong and so close.
I suspect something else is going on but can't tell what.
This looks like a case for @sar104 to look into.

 

[Rubistorm]

You hit on some of the strongest points, some things were happening without input from the pilot, the wind, which can be seen in the pilots video was relatively calm in the entire area, video stopped after the drone"got very loud, motors increasing to apparent over speed" hopefully @sar104 will take the case ! appreciate your input here/thank-you

 

[sar104]

The high speed was due to a yaw error. At 721 seconds the FC recorded a 160° CW yaw in 2 seconds.



That didn't happen, as is clearly shown by the gimbal yaw, which is correct, and confirmed by photos taken at 724 s and 734 s, in which the camera was clearly looking NW. Additionally there was no rudder input at that time.

I think we need to take a look at the mobile device DAT file (FLY014.DAT) to see what might have caused the yaw error.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[Rubistorm]

Very interesting' I placed the file on the same google drive since quite large, really appreciate your assistance here

Don Joyce Sept 1 Flight Log - Google Drive

drive.google.com

, thanks

 

[Elblasco]

You hit on some of the strongest points, some things were happening without input from the pilot, the wind, which can be seen in the pilots video was relatively calm in the entire area, video stopped after the drone"got very loud, motors increasing to apparent over speed" hopefully @sar104 will take the case ! appreciate your input here/thank-you

hello if you want I can read the files but with the text file it is not good I need the log file you know how to take it from the smartphone?

 

[Rubistorm]

Hi,
Above is 2 links to dat files and one txt file...did you try the link

 

[sar104]

Very interesting' I placed the file on the same google drive since quite large, really appreciate your assistance here

Don Joyce Sept 1 Flight Log - Google Drive

drive.google.com

, thanks

This is another case where I cannot see any explanation for the yaw error. It's clearly visible in the DAT data at 720 seconds:



While we don't know the exact details of the DJI flight control algorithms, we do know that the yaw is computed by transforming the rate gyro output into the earth frame of reference and biasing with the compass data. The only data that the FC has is from the rate gyros, accelerometers and compass, so if the two IMUs disagree wildly, as they do here, one would expect to find a significant difference in some or all of those input data. I won't post all the graphs, but in this case the rate gyros and accelerometers in the two IMUs agree extremely well with each other, and both take their input from the same compass.

Note the slight disagreement at 720 seconds between IMU0 and IMU1 magnetic yaw, which generally means an attitude disagreement that results in a different interpretation of the measured magnetic field. Sure enough, looking at the pitch and roll data:



Both pitch and roll show some disagreement, after having been in very close agreement for the flight up to that point. But while this accounts for the second (CCW) blip in IMU1 yaw at. 728 seconds, the large IMU1 yaw excursion occurs 5 seconds previously.

724.986 : 40125 [L-FDI]NS(0) FUSION(1): fault on , magn_heading_err_large​

If we accept the logged data as accurate, I can only conclude that these errors, that I've seen several examples of recently, are computational errors. Looking at the DAT event stream, while there are no entries that seem directly relevant, I have noticed that each of the events I've looked at has been accompanied by a large number of the following preceding entries:

717.580 : 39753 [L-VISION][VIO]receive vio data befor current ts||​

717.662 : 39758 [L-FMU/LED]action changed. Normal Flash:Ctrl forearm LED off by cam(2)​

717.662 : 39758 [L-FMU/LED]type:1, normal flash action:​

717.662 : 39758 [L-FMU/LED]c0:12,2;c1:0,0;c2:0,0;c3:0,0;c4:0,0;c5:0,0;c6:0,0;c7:0,0​

Pure guesswork at this stage, but I wonder if the FC is being overloaded.

@BudWalker?

 

[Rubistorm]

i noticed in the IMU_ATTI (0) GPS-H the signal/data at the same time is fluctuating to extreme....

 

[Elblasco]

Hi All,
A friend had a flyaway and the drone moved according to most of what we can determine over 90 KPH . DJI says wind gust . Which was on a day with surface winds about 10 KPH. Anybody able to help out here
here is link to dat file it is big 2. + GB unless a txt may be better ? Let me know, Sorry, new to this , not sure if even posting where it should be
Don Joyce Sept 1 Flight Log - Google Drive

Drone did execute a RTH , but we really would like to know what issue actually was....help ?

I have attached a txt file as well

Rubistorm,

according to what I see, they are right. However, having said this, the DJI GO 4 app when this has occurred has signaled you that you were flying faster? when I encounter gusts that make me go beyond the 80 km limits, I am told has this happened? and for how long have you traveled 90 km? sorry my english but I'm using google translate.

 

[Rubistorm]

sar104,Budwalker
so if FC is overloaded would you consider this a defect ? or just all that was happening was too much for the unit to calculate and correct ? Meaning a
15 mph wind did this ?

 

[Rubistorm]

according to what I see, they are right. However, having said this, the DJI GO 4 app when this has occurred has signaled you that you were flying faster? when I encounter gusts that make me go beyond the 80 km limits, I am told has this happened? and for how long have you traveled 90 km? sorry my english but I'm using google translate.

I was told it accelerated up to 90 in a matter of seconds , so it held for maybe a few seconds, no know display of overspeed as opperator was looking at drone and trying to get some reaction from the sticks

 

[sar104]

according to what I see, they are right. However, having said this, the DJI GO 4 app when this has occurred has signaled you that you were flying faster? when I encounter gusts that make me go beyond the 80 km limits, I am told has this happened? and for how long have you traveled 90 km? sorry my english but I'm using google translate.

It had nothing to do with wind gusts. It was a sudden yaw error.

 

[Elblasco]

sar104,Budwalker
so if FC is overloaded would you consider this a defect ? or just all that was happening was too much for the unit to calculate and correct ? Meaning a
15 mph wind did this ?

Has the application reported anomalies? or errors?

 

[dondroneson]

Hi Elblasco. I am the pilot and owner of the M2P that hit 90 kph. Just before the 'fly away', I was performing a low-speed hyperlapse (free mode). It was my first time trying a free mode hyperlapse, and was pleasantly surprised when a message came up saying 'press C1 or C2 to enter cruise control'. I pressed C1 and let go of the joysticks. I immediately received a 'cruise control cancelled' message. Tried this 3-4 times, then gave up and continued to fly manually. It was shortly after this that the aircraft accelerated out of control and I lost joystick control. FPV camera view was maintained at all times. (I was using Moverio AR glasses, incidentally.) I can confirm that at the time of the acceleration, the craft was definitely pointed roughly NW and did not swing around like the log shows. The craft did rotate later, but not at the start of the acceleration.

 

[Rubistorm]

It had nothing to do with wind gusts. It was a sudden yaw error.

Thank-you for your assistance on this,