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PostPosted: Thu 19. Sep 2019 21:39:51 
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Joined: Thu 29. Dec 2016 22:33:30
Posts: 3
Hello Tomas or anyone:-)
Having a difficult time getting position hold to work.
Using Spirit Pro with Geolink and 2 spectrum DSMX satellite receivers.
It will hold a relative decent position after take off but begin to drift soon after. I can hold additional aileron to maintain position but within a minute or so it will take full aileron to continue to hold position. So I must land. Upon landing swash does not go to level but maintains a lot of aileron typically right aileron.
Don't know how to fix this problem.
Also if I fly left or right or forward and release sticks gently to neutral then heli over corrects a lot in opposite direction I was moving heli.
Ie. Fly forward gently, release stick then rapid backward flight.
Finally if I hold position with stick input the system makes large step changes. Not always but typically jerky corrections.
I've tried different settings without luck.
So in my mind the control loop is too slow and corrections are to large.
To me this means P is too large and I is too small. That is if we are using P and I as described in a PID control loop.
P=Gain and I=Integral and D=derivative

Many years ago I used a DJI Wookong H system which I was able to set up and had wonderful performance.
Yes $1200 but also no longer available.
I am hoping with your help I can get to stable position hold for flying scale helicopters... graceful gentle change of direction.
I'm flying a Trex 550x on 6s at 75% throttle for low head speed and pitch restricted to , I believe 9 degrees.
Many thanks,
Larry

Update: Still playing with gains. Working a little better.
Added altitude hold on a different switch first flight went well.
Crashed on second flight when I turned off altitude hold. Heli descended fast to the ground in a vertical path as position hold was still active. Broke skids and tail blades.
Am wondering if collective stick position is important when altitude hold is turned off. Mine should have been in a hover position but cant say for sure. This could be a big issue if you are not aware of it. Thoughts???


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PostPosted: Fri 04. Oct 2019 16:21:14 
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Joined: Fri 04. Oct 2019 16:13:04
Posts: 3
Hi, I have the same problem, unfortunately I can't fix it, do you have any new knowledge?


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PostPosted: Sun 06. Oct 2019 20:53:17 
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Joined: Mon 29. Apr 2013 16:06:44
Posts: 9020
Hello,

if drifting start to occur then unfortunately this is caused very likely by very excess vibrations.
This would induce drifting also without GeoLink with Coaxial or Stabilisation mode only.

To confirm this, you can turn off all GeoLink features and enable only a Stabilisation mode.

This is nothing you could set in the software as the problem should not occur in a normal circumstances.

It should just hold position at any moment whenever you will start it. If not, then also other modes will likely be failing (even Rescue mode) as it is all related to the same issue.

Could you please measure vibration level - especially for Y axis?

When you will turn off any GeoLink feature it will return to the normal flight mode. So the collective pitch will work normally too which mean if it is under hovering position it will always descend. If it is above it will ascend. So the feature itself is not dependent on the collective pitch but normal flight mode is. So the model will do how the stick is set.

_________________
Spirit System developer


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