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Boeing 777 and Airbus 320 autopilot code

Postby honey4748 » Thu Oct 08, 2020 11:01 am

I have a question about the autopilot code.
Autopilot code on Boeing-777 or Airbus-320 When following a given waypoint through the route manager,
how does the plane follow by moving pitch, roll, yaw?
Is this possible because how to give the necessary flight command?
I need to understand in the code part.
Also, I would like to know the difference between the autopilot code of Boeing-777 and Airbus-320.
I need your help. :D
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Re: Boeing 777 and Airbus 320 autopilot code

Postby Octal450 » Thu Oct 08, 2020 4:38 pm

This is difficult to explain, I will do so a little later.

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: Boeing 777 and Airbus 320 autopilot code

Postby Octal450 » Thu Oct 08, 2020 10:36 pm

ok,
I designed both autopilot control systems of Airbus 320 and Boeing 777.
so basically for route manager I will explain it.

The route manager gives lots of infos, using the heading to the waypoint and the drift angle and a few other things, we can calculate a desired heading. Then, we feed this into an error signal which is made by taking the 180 period of the desired heading offset by current heading. That will gives us the proper error even between the 360 to 001.

Then this goes into a filter who's gain determines the target bank angle. The gain increases as a function of speed, so that at higher speeds the autopilot responds well for all configurations. The higher speed the less yaw at roll.

This is then fed into a roll deg error signal compared with current roll angle, which produces the target roll angle. From this we can use a fixed gain to calculate optimum roll rate. by using roll rate, we can minimize overshoots and oversteering, while maximizing precision. Also less reliying on integrators by doing this!

This roll rate demand goes into a Proportional-Integrator-Dervivative (PID) controller which moves the aileron servo according to the sum of the 3 terms response to the roll rate error. The PID setup is tuned precisely and scheduled by speed to remain precision controlling of the aircraft throughout the entire flight envelope. This last stage is basically what happens in normal planes, but since the 777 and A320 are flybywire (also done by me), I feed the A/P rate demands directly into the FBW, and the FBW's control system takes care of the rest.

That's how the roll channel works, simplified. the Pitch channel is far more complicated so i won't explain it now as its not related to route manager. the yaw channel is just some dampers on washed out yaw rate, and beta, as well as a turn coordinator.

Hope that helps!
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: Boeing 777 and Airbus 320 autopilot code

Postby honey4748 » Sun Oct 11, 2020 6:37 am

Thank you for your reply.
I will study through your writing.

Can I ask you another question if there's anything I don't know?
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Re: Boeing 777 and Airbus 320 autopilot code

Postby Octal450 » Sun Oct 11, 2020 4:14 pm

Yes, absolutely.

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: Boeing 777 and Airbus 320 autopilot code

Postby honey4748 » Wed Oct 14, 2020 2:25 pm

Dear Josh
I am a senior student at dept. of computer software at Korea Aerospace University
I contacted you for help.

I am using 2018.3.6 version and model is A320-200 with CFM56-5A1 engines.
I would like to write an XML code for the A320 to take off automatically using this version and model.
For example, I would like to implement a situation where I automatically take off using the ascent rate when I give it an ascent angle in code.

I am wondering if this XML code is possible and how to implement it.
Best Regards,
Taeheon Lee
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Re: Boeing 777 and Airbus 320 autopilot code

Postby Octal450 » Wed Oct 14, 2020 5:47 pm

Hi
I answered your email instead as I saw it first.

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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