my static calibration

Static, Dynamic, Log File Analysis, Troubleshooting

my static calibration

Postby trypt » Sat Feb 16, 2013 1:54 am

Did my first static calibration. Seems that I need more time for reaching higher temperature (?) Is there a problem to use more than a hour for the static calibrations? Seems that my basement is too cold :)

How do these curves look? There seems to be some issues with the ACC curve?

static-tmp.png


static-mag.png


static-rate.png


static-acc.png
trypt
 
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Re: my static calibration

Postby kinderkram » Sat Feb 16, 2013 10:27 am

Except for the acc curves at the beginning, all curves look very smooth.
The temp curve better goes from lets say -10 to +40 than -20 to +30 if you're not living in a polar region. ;)
You might want to add something to make it warm up to a higher temp like some cold/hot pack or something like this:

Image

Just don't overdo or it will heat up too fast.
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Re: my static calibration

Postby trypt » Sat Feb 16, 2013 12:28 pm

thanks! will try again.

Just curious, is the purpose of these static calibrations to make some sort of lookup table, so that the controller know how all the sensors react in different temperatures and can compensate for it?
trypt
 
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Re: my static calibration

Postby bn999 » Sat Feb 16, 2013 2:58 pm

I would not try to artificially increase the temperature or the rate of increase. Instead try to better insulate the board and/or reduce the volume of air trapped around it to allow slow, self heating do the job.
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Re: my static calibration

Postby trypt » Sat Feb 16, 2013 10:08 pm

I got the temperature right now, but the same ACC noise in the beginning. Could it be the foam when its warming up inside the box?
trypt
 
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Re: my static calibration

Postby kinderkram » Sat Feb 16, 2013 10:22 pm

If you use foam from an antistatic packing, yes.
http://autoquad.org/wiki/wiki/autoquad- ... libration/
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Re: my static calibration

Postby trypt » Sun Mar 03, 2013 3:22 am

OK, im now trying to do static calibrations again. Using a completely new box without any foam, just glued on some spacers for mounting the AQ board.

ImageUploadedByTapatalk1362277305.256950.jpg
ImageUploadedByTapatalk1362277305.256950.jpg (147.27 KiB) Viewed 5588 times


But I still get noisy/uneven curves on the ACC at the begynning...

Screen Shot 2013-03-03 at 3.18.18 AM.jpg


Screen Shot 2013-03-03 at 3.20.18 AM.jpg


This is from another try:

Screen Shot 2013-03-03 at 3.29.52 AM.jpg


Screen Shot 2013-03-03 at 3.22.10 AM.jpg


This is another try from a previous location a another box with foam:

Screen Shot 2013-03-03 at 3.44.52 AM.jpg


Screen Shot 2013-03-03 at 3.44.05 AM.jpg


Starting to get a bit frustrated, I have tried at least 5-6 times now at 3 different locations, with 2 different boxes with and without foam. I have freezed down the AQ both with and without the SD card in.

And the result is the same, noisy/uneven ACC curve at the begynning, so I´m starting to think it maybe is the ACC sensors that are unstable at this low temperature?

I have glued on the recoms with a gluegun as it said in the assembly guide, could it be that this glue is reacting to the cold temperature and is somehow affecting the accelerometer on the board?
trypt
 
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Re: my static calibration

Postby JussiH » Sun Mar 03, 2013 10:37 am

The noise you see is very likely temp shifting of the board mass. It can not be avoided completely!

You should be able to get a result with that data - the calibration software is able to filter out some noise.
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Re: my static calibration

Postby trypt » Sun Mar 03, 2013 11:54 am

Great thanks, thats good news :)
trypt
 
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Re: my static calibration

Postby JussiH » Sun Mar 03, 2013 3:24 pm

Another point:

If you dont plan to go flying at -10 degrees, then you dont need to freeze it that low. The recommandation is to capture a range that is 10 degrees C lower and higher than your expected lowest and highest flight temp.

But even at -10 degree ambient temperature, the board temp will be 5-10 degrees higher due to selfheating. So in most cases a range of 0-45 degrees C is sufficient...
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