IMU Both Failed

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Hi All,

I did IMU calibration ( Read somewhere its good to do now and then)

IMU1 failed with Automatic Orientation Error
IMU2 Failed with Temperature Out of safe Calibration range.

Battery is at 31 degrees C

History, I've flown the phantom 4 maybe 5 times, haven't had any issues, haven't crashed, now it won't fly.

about:



IMU readings:


I tried to calibration on a flat surface outiside. Any help would be appreciated.

I downloaded the DJI assistant for Mac, i calibrated everything via it, all worked fine. Just the IMU is failing.

Wes
 
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You probably have to send it back for repair.
 
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Have you guys tried resetting to factory settings in the Dji Assistant app on PC/Mac and reflashing the firmware?
 
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Looks like you're doing this job at home or outside close to it. Maybe some interference or subtle vibration in this area. Suggest you go somewhere else and try again. Flat surface and do IMU right after power on (colder better).

If doesn't work you might want contact DJI as possible problem customer can't fix itself.

Note generally speaking it is not recommended to have any magnet, metal, speakers etc near the drone. I.e sensors can be permanently corrupted in case of close contact dues to gauss effect.


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So I calibrated my IMU's yesterday on my P4 for the first time since I had it. Reason being it was taking 3 to 4% of my battery to warmup. So here's what I did.... I out the drone with a battery in the refrigerator! I left it in there for ten minutes and then cracked the door open, moved the Milk over and started the recalibration.

Went perfect. I believe 30C is pretty warm? You're supposed to get it as cool as possible for a calibration and have a flat surface.

I don't know if this will help. But that's what I did!


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The surface has to be perfectly flat with NO vibration or movement. The IMU has the accelerometer and the giros and any movement will mess up your calibration.
 
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Agreed! I put a nice chill on it first!

I was shocked when I flew next and when I turned it on it went ready to fly in less than a minute and the battery said 100% still! Not for long, but it made a huge difference.


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I have read somewhere that's because these sensors have calibration values correlated to temperature, therefore ready to go only when reaching temp for which there is registered values. This would explain why quicker ready to fly.


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I also read here that cold calibrations work better, I would like to know why? Wich components will have better calibration values in the cold that makes it a better. Why will they better? My last calibration was in cool weather 50 F and all is good. If we calibrate in the cold and fly in the hot, wouldn`t this actually offset real time accuracy. IMU has the accelerometer and giro, zero motion is zero it does not matter if it a cold zero or a warm one. Many people swear by this cold calibration and it most likely makes a difference. I just want to know the physics and logic for this procedure and what else is the IMU calibrating that prefers a colder environment? I have calibrated many industrial machines and most are calibrated at running temperatures to ensure optimal efficiency, why does this bird like the cold?
 
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P4 has very high density of electronics. It is known that heat is the enemy (actually both high and low temps) as inducing noise and errors (extreme case causing electrons jumping to near circuitry lanes!). Example;

TE Cooling - Important to sCMOS

Make sure P4 fan does work!

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When you fly the P4 gets hotter then when you calibrate and therfore those same errors would be present also. Just making sure your calibration is as clean as possible may help the final outcome then.
 

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