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HomeAircraftHelicopterAerial Photography and Video › How do you use your Co Pilot / General Laser for panos?
02-07-2006 07:15 PM  12 years agoPost 1
lele

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italy

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I have been reading in many posts that many of you guys use the IR stabilizer for taking panos, I tried that my self but can't get it to work.
I am using the General Laser and each time I do calibrate in the air.
But even if I get a "stable" hover as soon as I start to move the heli on a flat rudder turn it inevitably starts to fast drift in one direction so I have to abort the operation and take care of bring it it back to a safe position.
That could also be caused by the fact that there is some snow on the ground but I do not figure how such a system could really keep the heli level in a 180° turn. It could be simple to understand as such a system would not work since the reading of each of the 4 IR sensor is going to change so much during the turn but since I read that some of you use it for this purpose I could have missed something.
Thanks Lele
ps I did this but with out the GL.

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02-07-2006 07:22 PM  12 years agoPost 2
DANNO

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St. Petersburg, Florida

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im not sure what others are doing but on our system, the camera pans, the heli stays pointed in the same direction.

i was having the same problem you had and thats why i decided it was better to have the camera do the moving....

www.skypiximaging.com

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02-07-2006 07:26 PM  12 years agoPost 3
lele

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italy

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thanks Danno
I know you are a MASTER in panos.
I think it the same way of you. I think that Jeff and Angelos said once that for the panos they where using the aid of CP.
Lele

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02-07-2006 07:40 PM  12 years agoPost 4
Angelos

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nr Oxford, OX11, UK

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This one was taken at my early days of aerial photography and it’s not as good as recent photos. But it a good example of my method that just needs a flick of a single switch.

http://www.model-gadgets.com/camcop..._photos/200.jpg


I had my PowerShot G3 on continues shooting mode which takes around 5 photos every two seconds. The same switch that triggered the camera was also set to activate a fixed offset mix on the rudder channel. Now… because we all use heading hold gyros a fixed offset means fixed rotation speed. Flick the switch, wait for the helicopter to go around 2 turns under IR stabilasation and you get plenty of shots to stitch. Of course you have to choose the right value for the rudder offset so that the photos overlap. By the way... first rotate all photos to make the horizon level, then stitch.

-Angelos

Spartan RC R&D

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02-07-2006 07:59 PM  12 years agoPost 5
lele

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italy

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hi Angelos
thanks for reply.
I did exactly what you said.
I added a 20% offset to the rudder on same switch controlling the trigger. The problem is that as soon as the heli starts his slow rudder pan the IR stabilizer push it away from it's stable hover.
I think that this is due to the 4 Ir sensors reading a different value ( as they start to rotate) from the calibration they had.
I really hope that your inertila sensor will be ready soon!
Thanks
Lele

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02-07-2006 08:40 PM  12 years agoPost 6
CrashTestDummy

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CA - USA

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Maybe try tilting your IR sensor slightly. If the problem gets worse, tilt the other way. This might help. If your CG is off, I can imagine you may have this type of issue too.

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02-07-2006 08:48 PM  12 years agoPost 7
ELOSSAM

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Es

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Lele, before throwing your co-pilot sensor to the trash try with different gain values at the same day. Cant say if your problem is due to a high gain value or from a low gain one but what you explained had happened to my some days and didn´t happened many others. This weekend I tested the co-pilot sensor with Angelos AP unit and all the 360º turns where completely flat but also the Gasser was flown the same day and at the same conditions with similar results.

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02-07-2006 09:00 PM  12 years agoPost 8
Angelos

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nr Oxford, OX11, UK

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Lele is right. The helicopter will move and there is no way to avoid it. If it is bit cloudy and covers the sun it helps as the ground heat is more evenly spread. The other less noticeable cause is the wind. You trim the helicopter in one direction and when you turn 180deg it drifts twice as fast as the wind speed and the roll/pitch changes too if there are heat differences. The inertial sensor solves the heat problems and partly the wind problems. As the helicopter yaws, it will drift (change position) but the angle (roll/pitch) remains the same throughout the full turn.

-Angelos

Spartan RC R&D

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02-07-2006 09:01 PM  12 years agoPost 9
lele

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italy

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thanks Eloss
I will try that.
I was having a fixed 40% of calibration, I will try to add some and to reduce it...but still I can't figure how such device would keep level since when you calibrate it you are in a IR position that will be much different of the one you will get after only 40 degree of pan...
Tomorrow I will try different gains values.
Lele

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02-07-2006 09:05 PM  12 years agoPost 10
lele

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italy

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Angelos
I am sure that your inertial way is the way to go!
Lele

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02-07-2006 10:07 PM  12 years agoPost 11
ELOSSAM

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Es

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you are in a IR position that will be much different of the one you will get after only 40 degree of pan
Calibration has two stages, the oposite sensor calibration to define the leveled plane, and the air to ground calibration where the system is adjusted to know the IR differences between the air and the surface your flying over. Gain is a third part where you set the the amount of ciclic response to a certain amount of IR deviation.
I don´t know if your using the CP4 or the FS8 but I believe they use different calibration procedures.
IMO the calibration procedure is not critic. You can have a perfect leveled sensor unit but as your not flying in a perfectly flat surface with exactly the same IR reflection zones all around you heli will be tilted away from the higher or more IR reflective zones. Or you can have a non perfectly leveled unit and in the same way it will be affected by terrain. You don´t need to do daily air-ground calibrations but what you can do is adjust the gain. Playing in the lower gain side it will be less sensitive to this little terrain zones with high IR contrast. If you dont make daily calibrations you will find days where you will fly closer to the sensitive side and days where the heli seems lazy to be self stabilized but you have a slider to adjust de gain as needed. Your heli can do a 360º flat turn without the co-pilot so it must no be so different using it. Let the sensors help you but don´t let them dominate your heli with enough authority so turn down a little more the gain level of your unit.
If you increase the gain level your unit will be able to identify IR temperature differences between different terrain objects and that will make in unstable. Lowering the gain level it will react only to those large IR temp differences (i.e. air/ground) giving a more stable fligh.

Aaaaaaaaaaaamen.

Of course and as always I could be wrong and should be great to heard the opinion from others

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02-07-2006 10:33 PM  12 years agoPost 12
lele

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italy

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Eloss, thanks
I am using the General Laser.
your explanation is much interesting, tomorrow I will do some more testing.
Any way don't you also think that Angelos should a little hurry up with his inertial sensor unit! Please Angelos we are all waiting for you!
Since I believe that even if I could get out some more response from my IR unit, nothing would compare from a inertial sensor one where the IR horizon would not be a matter in stability, and would not be affected from different temperatures on the ground.
Thanks All
Lele

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02-07-2006 11:16 PM  12 years agoPost 13
ELOSSAM

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Es

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Out of any dude an inertial unit is much better but that´s what you can get for the price it costs.

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