Weird issue - Gimbal twitch - Mini 3 Pro w/RC

[mb34928]

I had an issue with my gimbal during low signal strength to my controller @ about 2300 FT out. I upload the logs to phantom help and there is 10 seconds missing during the time of the glitch

I did see and respond to a post of a similar issue, but it was Mini 2 that was landing. My initial concern was the gimbal twitch was due to low signal to the controller. However, I have return to home activated if my drone loses signal so that really shouldn’t have caused the gimbal to twitch.

Does anyone have any insight into this issue?

My equipment:
DJI RC (v01.03.0700 firmware)
Mini 3 Pro(v01.00.0700 - most current)
*realized this morning that there is a new firmware for the RC


Video segment from 19 Dec 2023

Log attached - missing 10 seconds starting at 5m 35.3s where the gimbal twitched.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Log attached - missing 10 seconds starting at 5m 35.3s where the gimbal twitched.

Any help or insight is appreciated.
Shawn

 

[GFields]

Log attached

*** Heads up *** There is no log attached

 

[mb34928]

how about now?

https://drive.google.com/file/d/1n7gSfra3VY0kFGc2ZhKo1vPg-7bW23mO/view?usp=drive_link

Log attached - missing 10 seconds starting at 5m 35.3s where the gimbal twitched.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[GFields]

how about now?

No. Are you pasting the URL or trying to upload the file? Just paste the URL

 

[msinger]

I upload the logs to phantom help and there is 10 seconds missing during the time of the glitch

There isn’t really a gap there. My log viewer doesn’t show the complete log in the map view. If you use Flight Reader instead, there is an option to show all data in the map view.

You can use the “Download CSV” link beneath the map to download the generated CSV log – which shows all available data.

I had an issue with my gimbal during low signal strength to my controller @ about 2300 FT out.

That wouldn’t have been caused by low signal strength. Something caused the aircraft to abruptly tilt steeply from side to side here:




Perhaps related to the braking that was logged at that same point in the log:

 

[mb34928]

That’s interesting that the gimbal did not adjust to keep the image level during braking event. Could a bird strike cause this?

Thanks for the pro tip re: flight reader

 

[msinger]

That’s interesting that the gimbal did not adjust to keep the image level during braking event

I don’t think the gimbal can adjust that quickly. A then it can only adjust so far too.

Could a bird strike cause this?

Most definitely. However, bird strikes are rare and your flight log doesn’t seem to show any signs of an object striking the drone.

 

[slup]

This haven't anything to do with a signal loss... this, as already said, it wasn't any. Don't really think it's due to any kind of "braking" either... and the gimbal twitch was correctly a result of the sudden large drone movements that made the gimbal to reach it's end point.

As the drone was flown with a full positive aileron stick command (dashed red) sideways to the right... a slight elevator command (dashed blue) was started to be increased ending up as a full command also. Just there where I've placed the chart marker the drone pitch (blue) down to much compared to the applied stick command, shortly after the drone starts to roll (red) to the left even though the aileron command (dashed red) was full command to the right. Shortly after this the drone yaw (black) slightly CW & then back uncommanded even though the rudder stick (dashed black) is in neutral.

All this looks much more as a momentary thrust loss in the front left based on the pitch, roll & yaw movements & their actual pilot commands... and also based on that the roll to the left exceeds the max specified widely as it reaches nearly -43 degrees.



A bird could be a reason but as something odd is recognized by the flight controller regarding the props already at the start of the flight (logged in the log event stream)... I rather think that the cause is prop or motor related.

 

[mb34928]

This haven't anything to do with a signal loss... this, as already said, it wasn't any. Don't really think it's due to any kind of "braking" either... and the gimbal twitch was correctly a result of the sudden large drone movements that made the gimbal to reach it's end point.

As the drone was flown with a full positive aileron stick command (dashed red) sideways to the right... a slight elevator command (dashed blue) was started to be increased ending up as a full command also. Just there where I've placed the chart marker the drone pitch (blue) down to much compared to the applied stick command, shortly after the drone starts to roll (red) to the left even though the aileron command (dashed red) was full command to the right. Shortly after this the drone yaw (black) slightly CW & then back uncommanded even though the rudder stick (dashed black) is in neutral.

All this looks much more as a momentary thrust loss in the front left based on the pitch, roll & yaw movements & their actual pilot commands... and also based on that the roll to the left exceeds the max specified widely as it reaches nearly -43 degrees.

View attachment 171653

A bird could be a reason but as something odd is recognized by the flight controller regarding the props already at the start of the flight (logged in the log event stream)... I rather think that the cause is prop or motor related.

View attachment 171654

I checked the propeller placement and they are in the correct spots. I'm going to check past logs to see if I get the same messages. I'll let you know what I find out. Thanks for your help.

 

[mb34928]

I checked the propeller placement and they are in the correct spots. I'm going to check past logs to see if I get the same messages. I'll let you know what I find out. Thanks for your help.

It appears that this message could display if the propellers are not unfolded properly, which could have been the case. Of the 80 logs on the controller only a handful gave the error "Check whether the propellers are attached to the correct motors based on their markings. Incorrect installation will cause the aircraft to roll over during takeoff (Code: 161000A2)".

I appreciate the help sorting this issue out. I'll keep an eye out for problems in future flights.

 

[Mark_Y]

I have seen the same gimble glitch on my mini 3 pro. I didn't explore the cause but thought it might have been due to the wind.

 

[mb34928]

I have seen the same gimble glitch on my mini 3 pro. I didn't explore the cause but thought it might have been due to the wind.

I have had slight gimbal movement on really windy days but not as extreme. As another commenter pointed out it was possibly due to my input going from full right to full left and the drone shifted to an extreme angle outside of what the gimbal can adjust for. If I recall correctly the signal strength to my controller started to go in the red so I shifted the aileron to the opposite direction to bring the drone back into signal range. I believe that is the most plausible explanation. Thanks for your input.

 

[slup]

...As another commenter pointed out it was possibly due to my input going from full right to full left and the drone shifted to an extreme angle outside of what the gimbal can adjust for.

In this flight that wasn't the cause...

If you look at the chart in post #8 again (click on it to make it full screen)

-& follow the Magenta colored graph (gimbal roll)...
-you see that just when that graph get a major negative but short deflection...
-both the elevator (right stick forward, dashed blue graph)
-& the aileron (right stick to the right, dashed red graph) was at at full deflection (both on value 1680)...
-no sudden going full right then full left with the sticks was recorded there.

This was how your sticks looked like when the gimbal twitched, right stick fully deflected forward & right:



The cause was instead major uncommanded drone movements, due to a unknown cause (seen on the blue, red & black graphs), that made the gimbal reach it's endpoint... you as a pilot didn't cause this with the sticks.

 

[mb34928]

In this flight that wasn't the cause...

If you look at the chart in post #8 again (click on it to make it full screen)

-& follow the Magenta colored graph (gimbal roll)...
-you see that just when that graph get a major negative but short deflection...
-both the elevator (right stick forward, dashed blue graph)
-& the aileron (right stick to the right, dashed red graph) was at at full deflection (both on value 1680)...
-no sudden going full right then full left with the sticks was recorded there.

This was how your sticks looked like when the gimbal twitched, right stick fully deflected forward & right:

View attachment 171693

The cause was instead major uncommanded drone movements, due to a unknown cause (seen on the blue, red & black graphs), that made the gimbal reach it's endpoint... you as a pilot didn't cause this with the sticks.

Thank you for the clarification. So could this be caused by a malfunction or solely external forces? Both?

On Airdata, you can see there is a deceleration from 21.9mph@5m 36.9s (right stick full left) to 2.0mph@5m 39.3s (right stick full right). Could going from 22mph to 2mph in a span of 2.4s explain the twitch?

My overall concern is the possibility of a malfunction that needs to be addressed with DJI.

Thanks again for your help.

 

[mb34928]

Thank you for the clarification. So could this be caused by a malfunction or solely external forces? Both?

On Airdata, you can see there is a deceleration from 21.9mph@5m 36.9s (right stick full left) to 2.0mph@5m 39.3s (right stick full right). Could going from 22mph to 2mph in a span of 2.4s explain the twitch?

My overall concern is the possibility of a malfunction that needs to be addressed with DJI.

Thanks again for your help

Click notifications to activate the 'HD Flight Player'

 

[msinger]

The cause was instead major uncommanded drone movements, due to a unknown cause (seen on the blue, red & black graphs), that made the gimbal reach it's endpoint... you as a pilot didn't cause this with the sticks.

At 5m 45.3s, the aircraft abruptly changed direction (right stick changed from full right to full up)
At 5m 46.1s, the aircraft started braking and the gimbal roll was unstable (shown in the video above)

This looks like the result of what the OP was doing on the sticks.

 

[mb34928]

At 5m 45.3s, the aircraft abruptly changed direction (right stick changed from full right to full up)
At 5m 46.1s, the aircraft started braking and the gimbal roll was unstable (shown in the video above)

This looks like the result of what the OP was doing on the sticks.

View attachment 171698

Also shows deceleration down to 1.9mph with no change is stick movement between 5m 45.3s to 5m 47.3s. I believe this is what @slup was referring to. I wish I had the ability to overlay the log onto the video to Id the exact moment match to the log.

 

[msinger]

Also shows deceleration down to 1.9mph with no change is stick movement between 5m 45.3s to 5m 47.3s

That makes sense since the aircraft was braking at that point in the log.

 

[slup]

You guys only look at some parts of the data & also only referring to the PhantomHelp logviewer presentation...

The bigger picture though... shows stick commands with the right stick first only full right, then while still being kept fully right, also slowly being moved forward (stick ends up in the upper right corner at 2 o'clock)...

If everything was healthy... the drone would during this sequence

-first only being rolled to the right with max tilt angle

-then when the stick also was being moved forward, the drone tilt would have been shifted from only rolled right max, to both rolled right + pitched front down

-but neither single axis should be able to reach max tilt angle anymore as the drone is limited to a max total tilt angle... the max tilt angle occurs in this case between the pitch & roll axis. The drone leans max into the 2 o'clock direction where it reaches the max tilt angle of 25 degrees.

So...

Stick movements alone can't explain the very odd drone movements coming in a moment after the right stick have reached the 2 o'clock position...

-the drone pitches nose up to about +19 degrees together with

-a sharp roll to the left (opposite direction) which exceeds the max allowed, -43 degrees.

-During this wild & uncommanded pitching & rolling the drone also yaws even though no yaw command is given with the left stick... it's in neutral position all the time.

This isn't a way a drone responds to a right stick positioned in the 2 o'clock position, & a drone is never allowed to exceed the max allowed tilt angle even if it's braking... instead it corresponds well with a momentary loss of thrust from the front left corner.

That the speed drastically decreases is easily explained... if the drone suddenly tilts in the opposite direction, that is effectively a full brake, so nothing strange there.

Again, study the chart in post #8, where all relevant data is gathered on the same time line, showing both the drones attitude changes together with the stick commands.

The cause for the thrust loss is another thing... debris in the motor that was thrown out before it stopped the motor totally, prop problems... or some outside force (bird?) that hit the front left corner... ???

 

[mb34928]

You guys only look at some parts of the data & also only referring to the PhantomHelp logviewer presentation...

The bigger picture though... shows stick commands with the right stick first only full right, then while still being kept fully right, also slowly being moved forward (stick ends up in the upper right corner at 2 o'clock)...

If everything was healthy... the drone would during this sequence

-first only being rolled to the right with max tilt angle

-then when the stick also was being moved forward, the drone tilt would have been shifted from only rolled right max, to both rolled right + pitched front down

-but neither single axis should be able to reach max tilt angle anymore as the drone is limited to a max total tilt angle... the max tilt angle occurs in this case between the pitch & roll axis. The drone leans max into the 2 o'clock direction where it reaches the max tilt angle of 25 degrees.

So...

Stick movements alone can't explain the very odd drone movements coming in a moment after the right stick have reached the 2 o'clock position...

-the drone pitches nose up to about +19 degrees together with

-a sharp roll to the left (opposite direction) which exceeds the max allowed, -43 degrees.

-During this wild & uncommanded pitching & rolling the drone also yaws even though no yaw command is given with the left stick... it's in neutral position all the time.

This isn't a way a drone responds to a right stick positioned in the 2 o'clock position, & a drone is never allowed to exceed the max allowed tilt angle even if it's braking... instead it corresponds well with a momentary loss of thrust from the front left corner.

That the speed drastically decreases is easily explained... if the drone suddenly tilts in the opposite direction, that is effectively a full brake, so nothing strange there.

Again, study the chart in post #8, where all relevant data is gathered on the same time line, showing both the drones attitude changes together with the stick commands.

The cause for the thrust loss is another thing... debris in the motor that was thrown out before it stopped the motor totally, prop problems... or some outside force (bird?) that hit the front left corner... ???

@slup, thank you for the detailed explanations and your patience. This whole process has been very educational for me. Thank you all for your input.