A Legitimate Near-Flyaway with My Fourth M2Z

[BudWalker]

I'm assuming the props were removed and the M2 never left the ground. This .txt shows the same problem. Just eyeballing it looks like height is the time integral of the IMU Z axis velocity up until about 20 secs.


Did you move/rotate the M2 at about 20 secs? The yaw data shows the M2 being rotated at 20 secs and the integral relationship between the height and velZ stops.

 

[sar104]

I'm assuming the props were removed and the M2 never left the ground. This .txt shows the same problem. Just eyeballing it looks like height is the time integral of the IMU Z axis velocity up until about 20 secs.
View attachment 91067

Did you move/rotate the M2 at about 20 secs? The yaw data shows the M2 being rotated at 20 secs and the integral relationship between the height and velZ stops.
View attachment 91068

Strangely, the time integral of the z velocity tracks exactly with the OSD height to start with, and then falls below it. That seems like the wrong deviation, so either the z velocity itself is being corrected after the height calculation is made, or something else is being used to derive height.

It's unfortunate that the accelerometer data are not available.

 

[new2mavic]

No matter what I do I cannot get the remote .DAT files to record.

Weirdly enough it will let me take off indoors but not outdoors. My thoughts are, if the accelerator is faulty as BudWalker suspects, pressure may be stable indoors enough for the AC to rely on the barometer alone - but not outside in the wind.
I did another IMU calibration just for the hell of it and without the props, indoors, everything seemed fine.

So I took it outside again. Same result, except this time it actually let itself smack into the pavement. Not that worried since I already have the ticket open with DJI for replacement. I started recording just in time for the plummet which you can compare to the flight data...

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I really wish I could get a .DAT for you guys. I reinstalled the entire app and cleared all the caches in the root folder so I am out of ideas.

It seems to me that both the z speed and height info are incorrect resulting in the flight controller sending wrong commands to the motors and the drone dropping out of the sky.

Everythings looks OK until time period A in which the throttle was reduced to zero. The z speed changed from ascending ( -ve value ) to descending ( +ve value ). This is still OK as the vertical speed probably cannot abruptly change to zero. However, the height continued to increase and did so at a higher rate. This is ABNORMAL.

In the following time period B, full throttle was appiled. The z speed changed to ascending and the height increased. Such response looked normal but what actually happened was the drone dropped rapidly to the pavement as shown in the footage. This is also indicated by the VPS data ( sWaveHeight ).

So for some reasons the sensors providing data for computing the z speed and height have malfunctioned. I am afraid it's time for the drone to return to it's real home - DJI.

 

[Kazzaaz]

I'm assuming the props were removed and the M2 never left the ground. This .txt shows the same problem. Just eyeballing it looks like height is the time integral of the IMU Z axis velocity up until about 20 secs.

Did you move/rotate the M2 at about 20 secs? The yaw data shows the M2 being rotated at 20 secs and the integral relationship between the height and velZ stops.

Actually that YouTube video is the flight log I posted - it was in the air! If you look at the PhantomHelp log you can clearly see the moment of impact as it dropped itself to the pavement.
Right when I began recording I did yaw, coincidence or not this is when the AC dropped.

I would really love to share a .DAT not only for you and sar but for myself as well -
Does anyone have any ideas at all on why I cannot get my phone (Samsung Galaxy Note 8) to record a .DAT?

 

[BudWalker]

Actually that YouTube video is the flight log I posted - it was in the air! If you look at the PhantomHelp log you can clearly see the moment of impact as it dropped itself to the pavement.
Right when I began recording I did yaw, coincidence or not this is when the AC dropped.

I would really love to share a .DAT not only for you and sar but for myself as well -
Does anyone have any ideas at all on why I cannot get my phone (Samsung Galaxy Note 8) to record a .DAT?

Sorry, I had just assumed that you were providing the .txt from the experiment that I requested. Props off, start motors and let sit for 3 minutes would isolate the stuff we're interested in. Namely, does the IMU z axis velocity data deviate from 0.0 when it shouldn't.