Mavic Mini tilts during a windy flight

[Deleted member 103366]

A few weeks ago my MM got caught in a gust and it is the first time I have been in a position to see it 'being blown away' i.e. blown 'sideways' relative to the original line of sight. A thread in here prompted me to look at the flight's DAT.
I see a needle like spike in the tilt of slighlty over 49deg and am curious, could this be real?
It was quite windy, the stuff at the end is me carrying it.

 

[scro]

Looks suspicious, assuming you've not changed any tilt limits in firmware. Was it a single point logged at the high tilt or is there a fast ramp in/out? ie does the rate of change of tilt around the spike look suspiciously high, or correlate well to other fast tilt changes? What were the 4 motors doing immediately before/after? Was there a big correcting blip on the motor(s) that were on the lower side/corner of the drone?

I've found that the aircraft can log a momentary tilt beyond the firmware limit, but these are usually only a few degrees beyond. I've scrutinised the log from a flight I did on a windy day (winds @50m between 10 and 14m/s) and had a few instances the tilt went beyond the firmware limits but never by much nor for long.

 

[Deleted member 103366]

Thank for the reply, it was a single, needle like point. Zoomed-in charts attached

 

[scro]

Bit confused with the graphs... There seems to be a spike in the roll value at approx 168.7 sec, but no corresponding spike in either the X or Y tilt graphs at that exact time. There is a notable spike around 164 on both X and Y tilt though?!

Also, any idea what's going on with the Y tilt at around 470 and 490? Some values well beyond 30deg there

 

[slup]

From what it looks, it's a second long tilt above spec ... most probably a gust that pushed the feather weighted Mini shortly, post the DAT itself ... much easier than to order views & get them delivered from you as screen shots.

 

[scro]

From what it looks, it's a second long tilt above spec ... most probably a gust that pushed the feather weighted Mini shortly,

That's basically what I was suspecting too. However, would that not show as a corresponding spike in at least one of the X and Y tilt graphs? Do you know what datum they reference? Aircraft, ground?

 

[slup]

That's basically what I was suspecting too. However, would that not show as a corresponding spike in at least one of the X and Y tilt graphs? Do you know what datum they reference? Aircraft, ground?

I've never used those signals from the DAT ... don't know what they show, just because they have "tilt" in the naming it's not necessary that they refer to that. It's much more straight forward to check pitch & roll & to see the combined tilt of the 2, check off the signal tiltinclination.

Example ...

 

[Deleted member 103366]

Also, any idea what's going on with the Y tilt at around 470 and 490? Some values well beyond 30deg there

Not sure at the moment, trying to work out how to correlate the info in the DAT csv with that in the txt csv.

At Slup, thanks but I don't post data, the drone got blown over neighbours' gardens and whilst I have had no complaints about in garden flights I don't wish to tempt fate

 

[Deleted member 103366]

It seems to me that the zero of time on the DAT charts corresponds to the start of the motors, and that that corresponds to the zero of time on the txt charts. Taking that to be the case then here are zoomed in charts for the time around 470 to 490 seconds.
The DAT and txt logs are numbered sequentially in my records hence txt log 0570 corresponds to the DAT 0394
I tend to like to fly side-on in wind so that I can switch the gimbal to FPV and see the drone's tilt hence some of the tilts during this flight might seem, in orientation, to be 90deg out from what might be considered to be normal.

 

[scro]

You hit a hole in time-space fabric at t478 ?

 

[Deleted member 103366]

Samatha Carter would be proud lol.
It was a rough day, more so because of the gusts. From memory the M2P even complained later on after I had decided it was a bit too blowy for the mini.


Incidentally if anyone is looking at their csv and wonders about some of the time stamps e.g. abc.xyz. In excel if you highlight the column then choose "format cell" and "custom" you can, fairly far down the list of options, select dd/mm/yyyy hh:mm (UK format) and the add :ss and it converts the number from a 'normal' number into a date with hours, minutes and seconds

 

[scro]

I went and had another look at my "windy day" flight log and found I was getting tilts of up to 45deg for brief moments, but mostly the tilt angle was 25deg or less. I have the tilt limit set to 40deg.

I had a look at the CtrlAllocation Raw_tilt_x and y signals. I don't know what they are, but they seem to be some derived values calculated at 1hz rather than the higher frequency IMU data streams. The IMU_ATTI(0) signals seem to give you the actual aircraft attitude data. Pitch/roll/tilt/headings all correlate well with the actual flight pattern.

 

[Deleted member 103366]

You might like to have a look at Budwalker's post, #18 in Flight logs can someone check them
I have a number of csv's of .txt flightlogs which are the result of runnng TXTlogToCSVtoolMM en-masse via the command line and when looking at some of those csv's they seem to end at column JO (APP_MESS.message) whereas .txt csv's that result from running CsvView run to column KH (OSD.yawUnWrapped:C) with the titles of the additional columns all ending ":C".

 

[scro]

I've been following that thread too, with interest. I wonder if there is a description of all the signals available in CsvView? Some of the names are obvious, but some are a bit cryptic. Some appear to be raw data, while others are calculated from the raw data streams. It seems a C suffix indicates a calculate value rather than a directly measured value.

I think we both share an interest in the nitty gritty engineering? that's going on in the flight controller and suspect you'll have read this thread too: pls help me understand pitch, roll and yaw angles in flight log

It was quite interesting reading up on quaternions. I think I just about got my head around the concept!

 

[WooZie]

@scro can you see my dat file, please? Csv view does not show me anything about motors, please, thanks

 

[Deleted member 103366]

@WooZie There seems to be a lot of data missing from that DAT, what drone is it from and can you post another DAT file for comparison?

@scro no I hadn't seen the thread, MOST of it, if not all, went straight over my head lol

 

[WooZie]

mini 2 my friend, i think that mini 2 can't be read, right?
all dat files are the same from mini2

 

[slup]

mini 2 my friend, i think that mini 2 can't be readed, right?
all dat files are the same from mini2

MM2 mobile device & AC DAT's are encrypted & can't be read by others than DJI ... only the TXT log is useful right now.

 

[Deleted member 103366]

Ah.....as far as I know you are correct in that the DAT's of the Mini 2 are unreadable.
I think I misunderstood the point of your post and thought you were asking Scro for assistance to read the DAT.

 

[WooZie]

indeed i asked him, because i have tried to read it with csv view but i couldn't, i supposed that mini2 can't be read like mm but not so in txt files can i see the rotation of motors? Thanks