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Mavic Mini - Motor Calibration
2295 5 2019-11-22
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PhasedSpaces
Second Officer
Flight distance : 179721 ft
United Kingdom
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Hi All,
Just a wee interesting observation . ..  My mini is brand new, I haven't had a chance to fly outdoors yet, so my initial flights have been confined to some test hovers and a few slow trips around the apartment.
I've controlled the mini with & without a phone attached, and it works just fine without .. VFR flight rules at it were ;-).

Anyway I noticed initially when the drone was on the deck with the motors spinning on flight idle, that there was subtle but noticable differences in the RPM of the various motors.  A kick of the throttle & with the mini airborne, the drone would sit perfectly horizontally & obey the commands sent to it perfectly. Thus the motors would 'even' up at the higher flight rpms.
However after 15-20 mins of hovering, basic  manoeuvering, landing and restarting, including powercycling etc.   I've now noticed that when starting the drone into flight idle, all 4 motors are now running in perfect sync as it sits there idling, this is even after taking the battery out & swapping for a different one....  
It seems that the mini does some running calibration of the motors after taking measurments in flight & on the ground, to even up the motor rpms once it's had a chance to sample how they perform.  
It feels like the drone has 'self tuned'.   Is this what it has indeed done?  
Has the mini permanantly 'written' this calibration to memory, thus demonstrating why it seems to have 'remembered' the motor tunings, after i had taken the battery out & swapped it.
I'm assuming that is is normal behaviour for all DJI drones?   
Has anyone else noticed this with their mini?
All good though :-)
2019-11-22
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nerkaid
lvl.2
Spain
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All the movement of the drone are done by adjusting the motors speeds, so if one motor was running different to the other, was probably because the dron was near to the wall or something like that and needs to compensate some air inertia to stay "static" or "idle".
2019-11-23
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PhasedSpaces
Second Officer
Flight distance : 179721 ft
United Kingdom
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nerkaid Posted at 11-23 00:10
All the movement of the drone are done by adjusting the motors speeds, so if one motor was running different to the other, was probably because the dron was near to the wall or something like that and needs to compensate some air inertia to stay "static" or "idle".

Hi,
Just to clarify. When the drone was initially powered up to flight idle (props spinning slowly, withthe aircraft sitting on a surface, NOT flying), on a large very level wooden surface (middle of dining table), well away from any walls for propwash to be an issue, the props were spinning at slightly DIFFERENT speeds.
I then took off after a couple of mins of idling, followed by hover tests & flying around for a while (20 mins).
Once the drone was back in the same spot in the middle of the dining table, far away from all walls etc.  I then  restarted the drone several times, power cycling and even swapping the battery. I noticed that when spinning back up to flight idle.     ALL 4 props are now in perfect sync!
My question is,  is this a fliuke or DOES the mavic perform a form of motor measurement and tuning?
I'm suspecting it does, but have others witnessed this?
2019-11-23
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Knapweed
lvl.4
Canada
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That's an interesting observation. It's tough to draw any conclusions without a larger sample size but I'm guessing those that already have the Mini have already exceeded twenty minutes flying time.
2019-11-23
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hallmark007
Captain
Flight distance : 8627812 ft
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Ireland
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IMU is what’s controlling that, even on the ground if wind blows through props IMU will kick in to correct the attitude of the craft, if your craft is not correcting its attitude then most likely a IMU calibration will solve its problem .
2019-11-23
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djiuser_X5uhqb7UPkii
New

United States
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I just replaced the front right arm and motor as one piece on my mini 2.  When I start it up the three original motors run faster than the new one so they all lift off and the new motor lifts but slower.  This causing the mini to lift as if a weight in in the new corner causing that front right side to grind into the ground.  I Han hold it and throttle it up and they all seem to pull hard.   Please help.  
2022-10-4
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