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Old Nov 30, 2012, 11:49 PM
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I've had a look at the Gluonpilot site.
The GP seems to share a lot of features with the UavDevBoard (I own a UavDevBoard).
Did you add a magnetometer ?
I would like to fly high and bring back some nice video but I dare not because I did not add a magnetometer to my UavDevBoard. This means that my autopilot will go berserk if the plane encounters high winds (if my plane flies backwards).
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Old Dec 01, 2012, 08:38 AM
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Quote:
Originally Posted by Paul_BB View Post
I've had a look at the Gluonpilot site.
The GP seems to share a lot of features with the UavDevBoard (I own a UavDevBoard).
Did you add a magnetometer ?
I would like to fly high and bring back some nice video but I dare not because I did not add a magnetometer to my UavDevBoard. This means that my autopilot will go berserk if the plane encounters high winds (if my plane flies backwards).
You're right - I think there are some similarities. I have not altered the GP in any way so I dont have a magnetometer.
However when planning a flight I try to allow room (speed!) for stronger winds at altitude but I have the downlink showing the plane's speed, altitude etc so I can abort if headspeed gets to slow.
What normally happens is that you get an swaying motion if the winds get to strong but I havent lost control becuase of high winds (yet!).

/Björn
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Old Dec 01, 2012, 08:38 PM
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Gluonpilot does look interesting. I have a plane outfitted with UDB3, and it does a very good job with speed and altitude control, but sometimes it doesn't follow waypoints very well. I have considered buying a GP setup, but spending $500 or so dollars on electronics isn't very high on the priorities list right now. I've enjoyed following your threads, though.

Tony
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Old Dec 03, 2012, 07:55 AM
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Hi Tony,

What do you mean by "it sometimes does'nt follow waypoints very well"?
I have not encountered this problem with my UDB.
I do have found that sometimes the GPS position can drift, sometimes as much as 50 yards, but that is not due to the UDB but to the GPS system.

Rgards,
Paul
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Old Dec 04, 2012, 09:01 AM
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Paul,

My aircraft will usually follow a sinusoidal pattern between waypoints, rather than flying a direct path. Sometimes it will skip a waypoint entirely, or veer way off course before suddenly veering toward the next waypoint. Honestly, I never considered that it might be a problem with the GPS and not the board itself. I'm using the EM406A GPS.

Tony
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Old Dec 04, 2012, 11:22 PM
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Hi Tony,

Obviously, the lateral gains are not well tuned. Is your airplane fitted with ailerons or is it rudder only ?

Paul
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Old Dec 05, 2012, 12:39 PM
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Paul,

Both, but set up with aileron nav only in options.h.

Tony
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Old Dec 05, 2012, 11:59 PM
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You could:

- Try to increase the YAWKD_AILERON gain to dampen the turn.

- You may also decrease the ROLLKP and YAWKP_AILERON gains to soften the turn.

- If you notice some roll oscillations then increase the ROLLKD gain or decrease the YAWKP_AILERON and ROLL_KP gains.
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Old Dec 06, 2012, 09:02 AM
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Thanks Paul. Sorry to hijack your thread, Björn.

Tony
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Old Dec 07, 2012, 04:00 PM
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Quote:
Originally Posted by t-turley View Post
Thanks Paul. Sorry to hijack your thread, Björn.

Tony
That's OK! I agree with Paul - sounds like a tuning issue with the UAVDevboard even if I have no experience with it.

When correctly setup the GP manages spot on navigation

Cheers,

Björn
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Old Dec 08, 2012, 09:53 AM
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Here's an example of how my plane follows waypoints; sometimes it has been even worse.

Tony
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Old Dec 08, 2012, 11:10 PM
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Hi Tony,

The result is pretty good by my standards. I think the gains values are pretty good. The wobble could be due to some wind gusts.

Did you let the algorithm estimate the wind by circling the plane around you a few times before switching the auto mode on ?

You can also switch the speed control on and choose a reasonable airspeed value. The algorithm has some difficulties to control the plane if the plane flies near its stall speed. And I suppose you know that in the real world the values of the control gains depend upon the airspeed, so it is better to keep the airspeed as constant as possible.

You should also try the CROSSTRACK option. It will help maintain the airplane true on track during long legs.

Did you keep the plane level during initialization ?
I hope I can help.

Paul
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Old Dec 09, 2012, 08:02 AM
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Paul,

I did circle around a few times before going to auto. According to Multiplex, the stall speed is 7 m/s, so I set the speed at 12 m/s. I also had the plane level during initialization. Speed control and altitude control were both very accurate. I tried CROSSTRACK once, but I don't think I had it set up correctly. I'll try again some time. Thanks.

Tony
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Old Dec 10, 2012, 05:51 AM
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Tony,

Increase YAWKD_AILERON by 30% and try the CROSSTRACK option.

I found on my simulator that the cross track control is a little stiff. This stiffness induces slight oscillations around the desired ground track. You can try, in the navigate.c function, to change the CTMARGIN value from 16 to 32 and the CTGAIN value from 2 to 1.

Note: CTGAIN * (CTMARGIN - CTDEADBAND) should equal 32.
CTDEADBAND is equal to zero.

The cross track control will be really sluggish this time but this will rule out any problem from it.

Paul
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Old Dec 10, 2012, 02:16 PM
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Thanks Paul.

Tony
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