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Baro problem or PID? [semi-solved]

PostPosted: Sun Jun 07, 2015 3:25 am
by jet
Hi, all.
Recently, I met a problem regarding altitude drop.
I had put a foam between DIMU and AQ6 to cover the barometer.

Yesterday, I spent 8 hours to do various tests.
However, I cannot overcome this problem.

Every test was 15 minutes.
In position mode, I let my AQ 6 flied forward again and again.
For the previous 3-4 minutes, the altitude was held well.
Then, the altitude was dropped.
The mag and acc were close to 2.1 and 9.8, respectively.
No visible vibration existed in the log files.
I also tried various foam materials.
The similar altitude drop occurred again and again.
Based on the tests, the accuracy of Baro became bad associated with time.

Does anyone have any solution?
Is the configuration of PID not well?
Thanks a lot.

Re: Baro problem or PID?

PostPosted: Sun Jun 07, 2015 5:48 am
by plexus
Hi,
The best way is to upload your log to see what to do.
Alain

Re: Baro problem or PID?

PostPosted: Mon Jun 08, 2015 8:52 am
by jet
Thanks Alain,
My AQ6 crashed today because of some tests.
However, before it crashed, I recorded a video and some photos regarding log.
Is it possible to define the problem causing Altitude drop?
The video: https://www.dropbox.com/s/scf9zzol35suk ... t.AVI?dl=0
The photos:
Clearly, the difference between pressu_alt and alt was high.
Any suggestions?
Thanks again.

Re: Baro problem or PID?

PostPosted: Mon Jun 08, 2015 10:28 am
by plexus
Hi,
To me it is difficult to see what happens with your log.
Can you post the Hacc and Vacc and too the ACCx with coordonates visible in flight hold is possible.
It will be instructive to see the curves of your motors (motor 0...3)
Your 3 seconds video is not explicit.
sorry for your crash

Alain

Re: Baro problem or PID?

PostPosted: Mon Jun 08, 2015 9:38 pm
by Florian75
Hello,

sorry for your crash :-(

Your altitude problem sounds to me for the "altitude speed P" "altitude speed "and "P max" Parameter. I set them both to 750. EDIT: No! Wrong Values. (I set "P max" = 150, "I max = 700, "Out max" = 700. ) Without increasing this, my copter comes down verry fast (sometimes).

Another Thing is the Trottle Factor. Do you have corrected it?

Regards
Florian

Re: Baro problem or PID?

PostPosted: Tue Jun 09, 2015 1:34 am
by jet
Thanks plexus and Florian,
Yes, I had corrected Throttle Factor.
However, I did not revised "P max."
I am repairing my AQ6 now.
I will test these suggestions.
Thanks again.

Re: Baro problem or PID?

PostPosted: Tue Jun 09, 2015 10:02 am
by jet
Hi, all.
My AQ6 was repaired with new motors, ESC, and prop (balance was done).
I tested my AQ6 again.
However, altitude drop still existed.
I had uploaded my log file (https://www.dropbox.com/s/k8wbw3g7hlx37 ... L.LOG?dl=0).
Based on the suggestion of Florian, my P/I/O max in altitude were 150/700/700, as figure shown.
Does anyone have any solution?
Appreciate you all.

Re: Baro problem or PID?

PostPosted: Tue Jun 09, 2015 9:17 pm
by Florian75
Hy Jet,

please Set "I Max" and "Out Max" to 750 and try again.

And your "Nav Alt Speed P" is verry low. Default is 200.

regards
Florian

Re: Baro problem or PID?

PostPosted: Wed Jun 10, 2015 1:04 am
by jet
Hi, Florian.
I had tried I/Out Max from 650 to 800.
Also, I tried to increase Tilt Angle P and decrease Tilt Rate D.
Altitude drop still exited.
So sad.
I may let AQ6 fly too low since the height of these tests was 2M.
Thanks a lot.

Re: Baro problem or PID?

PostPosted: Wed Jun 10, 2015 5:14 am
by chschmid
Hi Jet

Can you post a pict of how you covered the baro with foam please.

Cheers
Christof