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IT-AUTOFLIGHT

Controlling your aircraft, using the autopilot etc.

IT-AUTOFLIGHT

Postby Ivan-Pekar » Sun Oct 21, 2018 3:34 pm

Hello,
I have added the IT-AUTOFLIGHT onto to the An-24B. I have noticed some issues with the vertical mode. When I press LVL CHG (to climb), the aircraft's vertical speed decreases (please see video attached). Could someone please exxplain how to use the IT-AUTOFLIGHT's vertical mode? I have similar issues with landing, for example, when switching to HLD, the aircraft climbs or falls rapidly.

https://www.youtube.com/watch?v=ZkEHKjWPjTA

Thanks a lot,
Ivan
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Re: IT-AUTOFLIGHT

Postby Octal450 » Sun Oct 21, 2018 8:37 pm

Hi.
I will explain you the modes: (reference for V3.2.1, see top of it-autoflight.nas to see your version)
ALT HLD: A/P is holding altitude set
ALT CAP: A/P is capturing altitude set
VS: A/P is holding commanded Vertical Speed
FPA: A/P is holding commanded FPA
SPD CLB: A/P is using Pitch to Hold Airspeed set. The minimum clamp is 150fpm. So, if the aircraft is below the target speed, climb will be slow, if above, climb will be high. When at the speed, the A/P is holding the best climb rate for current power setting. If you increase power, aircraft will nose up. So what was your current speed in the video?
SPD DES: same as SPD CLB, except descent instead. Maximum clamp is -150fpm. Below target speed, descent will be fast, above target speed, descent will be slow. When at the speed, the A/P is holding the best descent rate for current power setting.
T/O CLB: Aircraft is holding set V2+10 speed with SPD CLB rules.
G/A CLB: Aircraft is holding the speed set at time of Go Around with SPD CLB rules.
G/S: A/P is following Glideslope
LAND: Glideslope data used for final descent toward runway (<= 100ft)
FLARE: A/P is flaring aircraft (<= 50ft)
ROLLOUT: Aircraft is lower nose, then keeping nose gear on ground after touchdown.

If your turning, you loose lift, and in SPD CLB, the nose will drop, because the speed will reducing. Is normal. But that depends on the plane.

Hope this explain you!

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: IT-AUTOFLIGHT

Postby Ivan-Pekar » Mon Oct 22, 2018 4:42 pm

Thank you very much, Josh.

In the video, my speed was 280 knots.

Ivan
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Re: IT-AUTOFLIGHT

Postby Octal450 » Tue Oct 23, 2018 12:31 am

Hi Ivan.
Than I don't know the reason. Can you make video showing it with HUD open? That I can diagnose if the problem is oscillation controller (how-to-fix here: http://wiki.flightgear.org/IT-AUTOFLIGHT#How_to_Tune), or another.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: IT-AUTOFLIGHT

Postby Ivan-Pekar » Wed Oct 24, 2018 7:22 pm

Yes, of course:

https://www.youtube.com/watch?v=K9uXKYxtWqM

Hope this is what you meant.

Also, I have many issues during descent. When I press ALT HLD, the aircraft descends!!! I end up crashing and having to use Instant Replay about 30 times to get at least a landing within the airport. As soon as the aircraft descends too low, I press FLCH, to climb, but it still continues to descend at a greater vertical speed!!!

Please see link:
https://www.youtube.com/watch?v=XXK_efSL3i8

Thanks,
Ivan
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Re: IT-AUTOFLIGHT

Postby legoboyvdlp » Wed Oct 24, 2018 10:48 pm

Sounds like you are stalling...? I'll watch the videos when I get home onto WiFi (cheaper than mobile data!)
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Re: IT-AUTOFLIGHT

Postby Octal450 » Thu Oct 25, 2018 12:58 am

Sorry
That shows me nothing of any use whatsoever.

Please have the HUD open (h key), do uncheck Enable 3D for the best of viewing it.

When you press ALT HLD, it holds current alt.

BUT: I think I know the issue... I forgot to mention, IT-AUTOFLIGHT relies on the GPS "instrument" for a reliable vertical speed sense. I used this because he acts the most like a ADIRS supplied Vertical Speed indication. Make sure your aircraft has this GPS item, you can go to /instrumentation/gps/indicated-vertical-speed, and make sure this value is working showing values, not just 0, or "" with no value.

This is mentioned in the installation guide here.

Kind Regards,
Josh
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Re: IT-AUTOFLIGHT

Postby Ivan-Pekar » Thu Nov 01, 2018 6:26 pm

Yes, of course:
https://www.youtube.com/watch?v=PevlTlWOMh4

I apologize about the late reply.

Josh, I was also wondering, whether it is possible to use the, for example, IDG-A32X autopilot system instead of IT-AUTOFLIGHT? I just personally find that autopilot easier to use (now that I'm used to it).

Thanks,
Ivan
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Re: IT-AUTOFLIGHT

Postby Octal450 » Fri Nov 02, 2018 12:20 am

Hi Ivan,
Something went wrong, don't know what. If you'd please zip your craft, and send it over to me, I'd like to further examine the installation. Perhaps there is something wrong or something I missed in the installation guide.

No, not possible. The A3XX Autopilot is based off IT-AUTOFLIGHT, but heavily modified to fit the operation of the real Airbus. Transferring it over would require transferring over the entire FMGC/MCDU system, and most likely the A32X electrical system, and possibly, more.

Kind Regards,
Josh
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Aircraft: A320-family, MD-11, MD-80, Contribs in a few others

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Re: IT-AUTOFLIGHT

Postby Ivan-Pekar » Fri Nov 02, 2018 1:47 pm

Hi Josh,
Where can I send it to? The e-mail option here in the forum doesn't allow attachments in the form of files.Also, would you like the an24b.zip file (without my adjustments of It-AUTOFLIGHT) or the an24b file with the adjustments?
In terms of IDG-A32X Autopilot, I see why now. Thanks.

Thank you
Ivan
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Re: IT-AUTOFLIGHT

Postby Octal450 » Fri Nov 02, 2018 3:22 pm

Hi, I sent you an email. Just reply normally to it :)

The one with your changes please, so I can check that it is installed correctly.

Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
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Re: IT-AUTOFLIGHT

Postby Octal450 » Fri Nov 02, 2018 8:11 pm

Hi Ivan,
You are right, I forgot to specify that IT-AUTOFLIGHT needs to know the gear agl above ground. This property is automatically created by YASim, but for JSBsim you need to add a calculation for it on your own. I will add instructions to the installation guide shortly. In the mean time, I will shortly PM you a copy of the plane fixed, then will update the doco.

Kind Regards,
Josh
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
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Re: IT-AUTOFLIGHT

Postby Maerchenprinz » Mon Nov 05, 2018 11:38 am

Hi!

I haven't yet looked at the code of IT-AUTOFLIGHT or how to implement it into an aircraft: All I can say is that the AN-24B has an autopilot which relies on different sources depending on different modes - and that everything is modeled correctly, all parameters are as they are there in RL...
I've written a "QuickStartUpGuide.pdf" with an "Autopilot AP-28L1" section. It's all on fgaddon, so maybe you rather give this a chance!
The "QuickStartUpGuide.pdf" fgaddon version tells you how the "real thing" :-) works!
I'm really sorry that I didn't come up with a manual before...

Ciao,

Adrian

EDIT: I wrote this in the the believe that IT-AUTOFLIGHT was a substitution for a bad or badly documented AP :)
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Re: IT-AUTOFLIGHT

Postby Octal450 » Mon Nov 05, 2018 9:19 pm

Hi Adrian,
IT-AUTOFLIGHT is for developers mostly to implement, to provide a stable base to develop modern autopilots for airliners. But anyone can install it on any aircraft.

Of course, using the AP designed for the craft is a better idea in my opinion. :)

Kind Regards,
Josh

PS: You may want to make a dialog for the AP, it makes it easier to use.
Skillset: JSBsim Flight Dynamics, Systems, Canvas, Autoflight/Control, Instrumentation, Animations
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Re: IT-AUTOFLIGHT

Postby Maerchenprinz » Sat Nov 10, 2018 7:00 am

Hi!

it0uchpods wrote in Mon Nov 05, 2018 9:19 pm:You may want to make a dialog for the AP, it makes it easier to use.


- Not really, there's everything needed in reach right in front of (respectively right from) the Captain; a dialog would rather be time-consuming for the user (and especially time-consuming for the one who had to write the dialog! :P ).

Ciao,

Adrian
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