[kOS] Plane PID Controller?

[Xyphos]

I'm having difficulty writing an autopilot script for normal air planes. I want my plane to take off from KSC then roll/bank turn to a parameter heading then hold altitude until program is terminated.

I can do the (crude) takeoff procedure just fine, and I know how to lock the steering after the turn, but I have no clue how to make a PID controller do a rolling bank maneuver to the desired heading.

[pellinor]

I have done this by locking the steering to the heading of the plane, plus a roll angle proportional to the heading error. So a simple p-controller, leaving the PID stuff to the kOS steering.

Edit: if it helps, the code is here (functions atmoLandingPlane or atmoAscentPlane, not well commented unfortunately):
https://github.com/pellinor0/kOS-MissionFramework/blob/master/Script/libatmo.ks

Edited July 12, 2016 by pellinor

[Xyphos]

23 minutes ago, pellinor said:

not well commented unfortunately

thanks a ton and no worries; I used to do software engineering (C/C++ & C#) before changing careers, so I'm quite used to picking through other people's code, though a bit rusty.
 now I have an example to work with and learn from. thanks!

[Dunbaratu]

I did this in my auto-landing pilot scripts from some older twitch episodes:

https://drive.google.com/folderview?id=0Bxkeai7oN35ffmFzZzZXTXZXWG9kUm5ERjhjR1pLcTBCZVJDX0FtVGltT2QtaUF1TTJqQVk&usp=sharing

(There's a lot in there besides just the "follow a heading" but the "follow a heading" stuff is there.)

It's basically a pair of nested PID controllers, like so:

PID 1 chooses a desired bank angle based on how far off the compass is from the desired heading.  The further off the compass is, the steeper  it wants to bank, up to a max bank of 45 degrees.

PID 2 starts from the output of PID 1, being given the desired bank angle, and chooses the roll control input based on how far off it is from the desired bank.

 

[Xyphos]

10 hours ago, Steven Mading said:

(There's a lot in there besides just the "follow a heading" but the "follow a heading" stuff is there.)

yeah, that's beyond my level of expertise. I understand (most of) the code but I don't see anything in there that would point my plane to a heading.