Please help tuning PosHold

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Please help tuning PosHold

Postby Cookiemonsta » Wed Jul 03, 2013 3:43 pm

Hi,

I have the following problem. My hexa does somekind dance around the target position.


My PID values are as follows:
PID.png
PID

MIXTABLE.png
MIXER

The lower rotors of the Y6 have 95% throttle ;)

The video to this flight is:
http://youtu.be/nAmmXt1_gao
(POSHOLD all the time with NO STICK-INPUT)

Any suggestions to get this thing flying perfectly are welcome ;)

For analytics I also uploaded the log datas:
Rate.png
RATE

ACC.png
ACC

MAG.png
MAG

motors.png
MOTORS

temp.png
TEMP
Cookiemonsta
 
Posts: 126
Joined: Thu Apr 11, 2013 3:31 pm

Re: Please help tuning PosHold

Postby JussiH » Thu Jul 04, 2013 12:24 am

First of all, your Accels are showing what looks like a lot of vibrational noise. That will degrade the estimation quite dramatically. Actually you are close to saturating the X/Y accel, so you need to look into that and try and reduce vibrations. That is the first thing to do.

Z-mag is also quite noisy, even when craft is static. You probably need to go over the wiring and find/eliminate the cause of this noise.

Pls post a screenshot of GPS_HACC - if its higher than 1 you wont get a very good pos or alt hold. Ideal is < 0.5

Have you verified calibration results:

http://autoquad.org/wiki/wiki/autoquad- ... on-result/
JussiH
 
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Re: Please help tuning PosHold

Postby Cookiemonsta » Thu Jul 04, 2013 8:15 am

JussiH wrote:First of all, your Accels are showing what looks like a lot of vibrational noise. That will degrade the estimation quite dramatically. Actually you are close to saturating the X/Y accel, so you need to look into that and try and reduce vibrations. That is the first thing to do.

Z-mag is also quite noisy, even when craft is static. You probably need to go over the wiring and find/eliminate the cause of this noise.

Pls post a screenshot of GPS_HACC - if its higher than 1 you wont get a very good pos or alt hold. Ideal is < 0.5

Have you verified calibration results:

http://autoquad.org/wiki/wiki/autoquad- ... on-result/


Hi Jussi,

I verified the results and they didn't look that bad, actually I opened a thread for comments on the calibrated result :
http://forum.autoquad.org/viewtopic.php?f=35&t=2447

As you requested here is the HACC plot:
GPS_HACC.png
GPS_HACC

It's way below 1 meter.

The above ACC plots were made in a very gusty and windy flight. So for a better comparison I add some plots of the ACC and the pitch and roll Inputs during a series of flights in PH when there was NO wind at all.

ACC_no_wind.png
ACC NO WIND

Pitch_Roll_no_wind.png
PITCH AND ROLL INPUT NO WIND


I hardmounted the FC and tried to reduce the vibrations by balancing my motor-prop combo with a laserpointer to almost perfect. Previously I tried rubber standoffs but they made it even worse so I don't really know what else to do. Do you have an advice to get that x/y accels calm down?

Thanks for any suggestions and help! :)
Cookiemonsta
 
Posts: 126
Joined: Thu Apr 11, 2013 3:31 pm


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