Mavic mini up and down with no operator command

[Mavic_Mini_Pilot]

But, just to clarify, this doesn't look to me at this stage to be related to the multiple reports of uncommanded descent where the aircraft simply descends uncontrollably to the ground.

To me it looks like the Mini is just doing everything correctly and properly. I think that this whole not being able to maintain altitude thing is just the Mini thinking that it is doing something that it should. For example, for some reason the Mini thinks(senses) that it is going up, altitude rising(maybe being blown up in the air, or something) and all its doing is just correcting for that rising that it has detected by decreasing altitude, doing down.

The above is just me speculating and thinking, but I really do hope that it turns out to be something that can & will be fixed via a Firmware update.

cool cool

 

[sar104]

To me it looks like the Mini is just doing everything correctly and properly. I think that this whole not being able to maintain altitude thing is just the Mini thinking that it is doing something that it should. For example, for some reason the Mini thinks(senses) that it is going up, altitude rising(maybe being blown up in the air, or something) and all its doing is just correcting for that rising that it has detected by decreasing altitude, doing down.

The above is just me speculating and thinking, but I really do hope that it turns out to be something that can & will be fixed via a Firmware update.

cool cool

No - I don't think that is the case. It should not be going up and down without stick inputs, and when it does go up then that vertical motion should always be detected by the IMU - not just sometimes. It's clearly a fault.

 

[Mavic_Mini_Pilot]

No - I don't think that is the case. It should not be going up and down without stick inputs, and when it does go up then that vertical motion should always be detected by the IMU - not just sometimes. It's clearly a fault.

I think that the drone thinks that it is being blown up and it tries to compensate by going down. There are no stick inputs at all here, say its just hovering 20m above ground and then something happens that the drone actually thinks/senses it is being pushed up - and compensates by going down. This way it is ok for the IMU to sense that vertical motion you've mentioned, that is what it is compensating for!

It just makes a lot of sense to me that the drone is reacting to something when it does altitude increases or decreases. That it somehow thinks that what it is doing is alright.

I really am pointing out that this is just what I think, I may be wrong and most probably am - but nothing else makes sense to me. I'm very happy and glad to be a part of this wonderful community with such smart people like you to help us out. I really am looking forward to DJI solving this very soon, hopefully they're looking into this also.



But yeah, probably some IMU / accelerometer / barometer/ FC thing..

LOL

 

[sar104]

I think that the drone thinks that it is being blown up and it tries to compensate by going down. There are no stick inputs at all here, say its just hovering 20m above ground and then something happens that the drone actually thinks/senses it is being pushed up - and compensates by going down. This way it is ok for the IMU to sense that vertical motion you've mentioned, that is what it is compensating for!

It just makes a lot of sense to me that the drone is reacting to something when it does altitude increases or decreases. That it somehow thinks that what it is doing is alright.

I really am pointing out that this is just what I think, I may be wrong and most probably am - but nothing else makes sense to me. I'm very happy and glad to be a part of this wonderful community with such smart people like you to help us out. I really am looking forward to DJI solving this very soon, hopefully they're looking into this also.



But yeah, probably some IMU / accelerometer / barometer/ FC thing..

LOL

The main reason that I am sure it is a fault is that the aircraft has two methods to measure vertical motion - the accelerometers in the IMU and the barometric pressure sensor, and one of those is not detecting the motion. So whatever the cause of the vertical motion, part of the flight control system is not seeing it, at least intermittently. That's a serious problem.

 

[Mavic_Mini_Pilot]

The main reason that I am sure it is a fault is that the aircraft has two methods to measure vertical motion - the accelerometers in the IMU and the barometric pressure sensor, and one of those is not detecting the motion. So whatever the cause of the vertical motion, part of the flight control system is not seeing it, at least intermittently. That's a serious problem.

Watch this video, here the sensor data is displayed and clearly show the barometer is not very accurate. Not sure about the IMU, but if you watch you'll see the altitudes all over the place.

I also watched another video on YouTube where this guy says he noticed that while flying his Mini the previous day at -20C' that the drone would sometimes rise and at other times lower its altitude all without any stick inputs on the TX, just all by itself. Can't find it now but will let ya know..

cool cool

 

[sar104]

Watch this video, here the sensor data is displayed and clearly show the barometer is not very accurate. Not sure about the IMU, but if you watch you'll see the altitudes all over the place.

I also watched another video on YouTube where this guy says he noticed that while flying his Mini the previous day at -20C' that the drone would sometimes rise and at other times lower its altitude all without any stick inputs on the TX, just all by itself. Can't find it now but will let ya know..

cool cool

Both the accelerometers and barometer can easily resolve this kind of vertical motion when working correctly. And you can see them doing exactly that for much of the flight record. The abnormal parts of the records are definitely abnormal. The barometric readings may drift slowly over the duration of a flight, but not during individual climb and descent maneuvers.

And stop watching YouTube - it's 90% misinformation on these kinds of subjects.

 

[Myha]

I downgraded my firmware to the previous version and everything has been fine since.
Definitely a possibility of different hardware as another Mini flyer has no problem and he bought his at the same time as I did and it works fine with the latest firmware.
Just have to wait for another update I guess.