"Montblack" wrote

Automotive world is using electronic stability-control (ESC) systems with
documented success.

I'm guessing some variant of this is what you'll eventually cobble
together
in your garage.

More than likely, they are using piezzo electric rate sensors for the
direction information. They are relatively cheap, and do well at sensing
rapid changes. They have been used for a while in the RC airplane world, as
a stability aid, with good success, also. Any really stable electronic gyro
system in the commercial auto-pilots world, are much more expensive, and as
far as I know, not available to the public.

Problem is, piezzo sensors have a fairly fast "drift." which makes the
leveling ability good only for a few seconds. If you handed over control to
one of these units, within 30 seconds, you would be upside down, and the
unit would think everything is still OK.

In the RC world, if the plane makes a sudden move to go upside down, it
senses the sudden move and if the sticks have not commanded the sudden move,
it will move the control surfaces to stay right side up. It counts on you
keeping it somewhat upright, and recalibrates itself often - based on your
MarkII eyeballs telling the plane to fly level.

Same thing with the car unit in the links. It knows that you are going
straight, or following curves. (still reasonably slow changes compared to
sudden loss of control) It continually reminds itself that it is going
straight, and re-sets itself. Only when a real sudden move is made, does it
correctly sense that it is not going straight and the steering wheel wants
the car to go straight. The computer then makes corrections to keep the car
straight.

If a plane wing leveler were based only on these units, and the plane
started banking very slowly, the sensor would not realize it. That is the
drift. It would re-set as level, then the plane banks another slow degree,
and the unit re-sets, and the plane banks...you get the picture.

I believe the concoction that had some success, was a GPS wingtip
differential altitude sensor. It used these rate sensors in unison to help
backup the control movements and make the controls smooth. The units
re-set using the GPS info as the reality of what was level. You have to use
something (MarkII eyeballs or GPS) doing this.

Good luck to the OP, figuring out a homemade wing leveler. It is a tough
problem.
--
Jim in NC