Digital flight control research from the '80s

I tripped over this on my suggested links and thought it might be of interest to the DIYD crowd.  Fascinating to see an original Macintosh being used as a ground station!

Views: 766

Comment by Cliff Dearden on March 2, 2015 at 6:54am

Beautiful !!..... I wonder what those guys are doing now?

Comment by Daniel Nugent on March 2, 2015 at 8:22am
I love it! Great video.
Comment by Gary McCray on March 2, 2015 at 10:58am

Hmm! APM mark .0001 Alpha

Great video

Comment by Eli Cohen on March 2, 2015 at 2:32pm

Literally just read a paper from Ilan Kroo the other day (tailless aircraft paper). Fantastic resource for people working on flying wings.

Comment by Stephen Gloor on March 3, 2015 at 2:00am

Makes you wonder how unstable our UAVs could be and still fly.  Relaxed stability gives more efficient flight sometimes and a greater maneuver envelope potentially.

I have a couple of times been guilty of launching a plane in stabilise or FBWA mode that has been completely out of trim and flown around easily and then switched to manual and have it nearly crash before I can cut the autopilot in again.  It is amazing (when you are dumb enough to do it :-)) what the APM will compensate for.

Comment by Andrew Rabbitt on March 3, 2015 at 3:07am

It would be fun to explore this Stephen, but I think there are two issues that might arise.  Firstly the extra servo work might cost you flight time in mAh rather than L/D and secondly, (I think) you'd need a pretty reliable airspeed sensor to add in your stabilizing function which needs to operate all the time, not just in FBW and Auto modes.

Actually, I wonder if just by having an open-loop airspeed-vs-pitch trim function whether this would be enough to add synthetic stability without needing any high-speed feedback loops running.  After all, this is all static margin is going you, isn't it?

Comment by Stephen Gloor on March 3, 2015 at 3:19am

Yep - they had an angle of attack sensor as well as this would be pretty critical.  An accelerometer or magnetometer can only give you a pitch angle not one referenced to the on-coming airstream.

Comment by Stephen Gloor on March 3, 2015 at 4:42am

And if this is the same Steve Morris then he at least has done a fair bit since

https://www.youtube.com/user/smorrismlbco

http://mlbuav.com/

Comment by Andrew Rabbitt on March 3, 2015 at 4:51am
I think if you have an accurate airspeed signal you should be able to infer angle of attack from that and the acceleration vector
Comment by Stephen Gloor on March 3, 2015 at 4:58am

You might need two and use the speed difference between them to estimate it.  Mind you I could just take the Penquin out this week and move the battery back a bit and see how it goes.  I also have a wing that is eventually getting an APM so it could be a good test.

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