Mini 4 Pro Unstable on the pitch axis

[jwilson]

Not really. Today they've informed me that they cannot analyze my logs because I am using "third party software".

View attachment 174124

What third party software are you using? I flew my mini 3 pro with dronelink and litchi beta yesterday. I'm pretty sure when you fly with those, it voids the warrenty.

 

[BudWalker]

Is this also seen when flying sideways (only aileron), or backwards? And is this tied to the OD mode bypass only... if so it's something else than a tune issue.



Those really slow oscillations usually comes from a high I... which is dampened by rising P, which in turn can require a higher D.

Don't know about flying sideways, backwards or Bypass mode. I'll be heading out a little later to do some test flights.

 

[BudWalker]

Another example of this behavior was posted over on DJI forums
Mini 4 pro oscillating

This one is a little more interesting as it shows also a longer period oscillation in horizontal speed.

 

[TinajaEco]

Is this also seen when flying sideways (only aileron), or backwards? And is this tied to the OD mode bypass only... if so it's something else than a tune issue.



Those really slow oscillations usually comes from a high I... which is dampened by rising P, which in turn can require a higher D.

Mine does not exhibit this behavior flying in reverse, only forward into a head or crosswind.

Dead calm last evening so I was unable to test with OA off.

DJI is being less than helpful. Just endless repetitions of circular diagnostic questions being asked over and over again.

 

[tuxtard]

What third party software are you using? I flew my mini 3 pro with dronelink and litchi beta yesterday. I'm pretty sure when you fly with those, it voids the warrenty.

I use RC2 with a FCC patch, custom launcher and DisplayLink driver. I guess they are talking about FCC patch.

 

[BudWalker]

I use RC2 with a FCC patch, custom launcher and DisplayLink driver. I guess they are talking about FCC patch.

I think they are probably talking about the use of the PhantomHelp viewer to create the .txt to .csv and, then, CsvView to view the .csv. You might try providing the .txt log file instead and suggest they use their proprietary software to analyze it.

 

[tuxtard]

I think they are probably talking about the use of the PhantomHelp viewer to create the .txt to .csv and, then, CsvView to view the .csv. You might try providing the .txt log file instead and suggest they use their proprietary software to analyze it.

Yeah, maybe. DJI never asked for the original TXT files. They probably don't want to bother as only me and one other guy provided them with logs. I will send them original TXT files anyway, but I think that they will only take it seriously if more pilots provide logs on the official forum.

 

[davidarmenb]

Another example of this behavior was posted over on DJI forums
Mini 4 pro oscillating

This one is a little more interesting as it shows also a longer period oscillation in horizontal speed.
View attachment 174179

Apologies for the unrelated post but which flight log app/reader are you using to get data plots over time like that? I haven’t seen these graphs in the log readers I’ve used!

 

[Droning on and on...]

Mine does not exhibit this behavior flying in reverse, only forward into a head or crosswind.

Dead calm last evening so I was unable to test with OA off.

DJI is being less than helpful. Just endless repetitions of circular diagnostic questions being asked over and over again.

This sort of thing always makes me worried they're working on it and are having a tough time fixing it.

Pure speculation: They're trying to fix it by tuning the PID, but every set of values that get rid of the oscillations has some other problem, like sluggish response or messes up OA.

Further complicating things is the FC is controlling for GPS groundspeed and the pitch stick position maps proportionally to that, not tilt angle. So it's more complicated than a simple PID control loop.

This is likely why it only happens in a headwind.

 

[BudWalker]

Apologies for the unrelated post but which flight log app/reader are you using to get data plots over time like that? I haven’t seen these graphs in the log readers I’ve used!

I use CsvView. It's free and can be obtained here

CsvView Downloads

First use the PhantomHelp Flight Log Viewer
DJI Flight Log Viewer | Phantom Help

Then download the .csv that it creates


Finally, submit that .csv to CsvView

 

[BudWalker]

Just got back from doing a test flight. Tried forwards, backwards and sidewards. Full and partial stick input. Bypass, no OA and Sport modes. Into the wind, down wind and cross wind. Didn't see any evidence pitch oscillations.

I feel cheated.

 

[tuxtard]

Just got back from doing a test flight. Tried forwards, backwards and sidewards. Full and partial stick input. Bypass, no OA and Sport modes. Into the wind, down wind and cross wind. Didn't see any evidence pitch oscillations.

I feel cheated.

I don't know if that is good or bad news. Maybe wind conditions were not favourable for this phenomenon or just maybe we who experienced this issue have faulty units.

 

[Droning on and on...]

I don't know if that is good or bad news. Maybe wind conditions were not favourable for this phenomenon or just maybe we who experienced this issue have faulty units.

It suggests Gremlins are at play

 

[tuxtard]

I have another observation to share which might be a clue. The other day I was flying near a lake. It was a very calm day and I had no oscillation problems, but I noticed this:



This photo was taken with 0º camera tilt (i did camera reset to make sure). You can see that X is pointing to the water instead of the shore. Does this mean that drone "thinks" it is at a slightly different pitch angle that it actually is?

 

[TinajaEco]

Mines getting shipped to DJI for “evaluation by the engineers”.

Had to call a second and make a small stink to get anything done.

 

[tuxtard]

Mines getting shipped to DJI for “evaluation by the engineers”.

Had to call a second and make a small stink to get anything done.

Good luck, I hope it gets fixed.

May I post your video from the post #31 to the official forums so that others can see how this issue looks like?

 

[TinajaEco]

Good luck, I hope it gets fixed.

May I post your video from the post #31 to the official forums so that others can see how this issue looks like?

Yes.

 

[tuxtard]

Mines getting shipped to DJI for “evaluation by the engineers”.

Had to call a second and make a small stink to get anything done.

Hi. Did you get response from DJI yet about the evaluation?

 

[Droning on and on...]

I just experienced this oscillation briefly, about 5 or so up and down swings, flying backwards at full speed, no appreciable winds. It might have continued but I had to stop (about to fly over people).

It was very odd, and would have freaked me out a bit had I not read this thread.

I couldn't reproduce it in either direction.

 

[BudWalker]

I just experienced this oscillation briefly, about 5 or so up and down swings, flying backwards at full speed, no appreciable winds. It might have continued but I had to stop (about to fly over people).

It was very odd, and would have freaked me out a bit had I not read this thread.

I couldn't reproduce it in either direction.

Can you provide the .txt log for this flight?