wing levelers

wrote:

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards


The hard part is the electronics package between the two. I know the
systems I worked on, but I would be reluctant to attempt builing a
system. Not my bowl of rice, but I'd like see what others come up with.

Dan, U.S. Air Force, retired

"Dan, U.S. Air Force, retired" wrote in message
news:rhLVd.21112$Sn6.10965@lakeread03...
The hard part is the electronics package between the two.

It wouldn't be that bad, really. At least not for just a rate damper. The
R/C gyros put out pulse-width modulation signals, which are pretty easy to
work with. Also, there are a lot of decent servos out there that can read
it.

I think the hard part of the rate damper project is making sure you don't
overtorque something important in your airplane, and setting things up so
that, when the damper servo goes haywire, that you can turn it off and
revert to a normal airplane quickly and without hurting anything/anybody,
and that while you're busy figuring out that something is going wrong, that
you can overpower anything it's doing that you don't like.

More than a few people and quite a few airplanes have gotten killed in the
process of engineers trying to figure out how to do all this automatic
stabilization and fly-by-wire stuff. It's not something approached casually,
unless it's for a toy that's OK to crash (R/C model). In my somewhat short
career as a flight controls engineer (12 years), I've seen 3 airplanes lost
and more than a couple of close calls due to control design issues. Even
when everything works as designed, there are man-machine interaction
problems that can kill you. Even apparently innocuous things. Think back to
that Airbus that busted up a couple of years ago in New York. I think
there's an article in Flying this month about it. Nothing there that jumps
out at you as an obvious hazard, but it got a couple hundred people real
dead.

I'd really hate to see someone on this newsgroup go out and get himself
killed trying to invent something without full cognizance of the hazards.

Pete

Dan, U.S. Air Force, retired wrote:
wrote:

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards


The hard part is the electronics package between the two. I know the
systems I worked on, but I would be reluctant to attempt builing a
system. Not my bowl of rice, but I'd like see what others come up with.

Dan, U.S. Air Force, retired

Dan, did you ever get a chance to work with fuzzy logic?

It would require a stepper motor to control the control surface, but it
could easily maintain wing level or altitdude with grace and smoothness.
Have you ever seen the balancing trick with the mortorized car.

A weight on the end of a stick is hinged on top of a programmed electric
car. The car acclerates quickly to flip the weight vertical, and then
jostles back and forth to balance it there. All with not input except
an indicator of the angle of the stick holding the wieght. Impressive.

I have the information for the EZTrim altitude hold system. After I
have everything else on the plane working, I have a goal of reworking
the software to use a fuzzy algorithm.

The good news is thats the part that has gotten more doale in recen
years. Electronics that used to take a dozen guys to tweak, one kid
with a PC and PIC can do. He may not understand the application, but
the implementation technology has gotten quite powerful and cheap.

Fuzzy Logic, from what I can tell, if you do a really good job, you can
get to where a properly tuned PID controller would be, but without that
pesky math.

Now neural networks, that would be something to see. Watch the network
learn how to fly from a few simple rules 1) Stall is bad 2) crashing is
really bad 3) Its good to keep the oily side down. I think I'd have
it learn that sucker learn the basics flying an model (R/C or
computer).

Stepper motors- Why go to all the trouble when you have cheap off the
shelf full up servos?

Dan, U.S. Air Force, retired wrote:
wrote:

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would
probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards


The hard part is the electronics package between the two. I know the
systems I worked on, but I would be reluctant to attempt builing a
system. Not my bowl of rice, but I'd like see what others come up
with.

Dan, U.S. Air Force, retired

On Wed, 2 Mar 2005 08:30:27 -0800, "Pete Schaefer"
wrote:


"Roger" wrote in message
.. .
To paraphrase the manual for my auto-pilot. When encountering more
than moderate turbulence, turn off the autopilot. I believe Pete
touched on this as well.

Driving an auto-pilot too hard can put your servos on the rate limit. On a
rate limit, a servo develops serious amplitude-dependent lag, which can
destabilize your loop closures. THe way arount this problem? Big, huge,
powerful, fast servos. This solution opens up a whole other can of worms.

Ahhh... That's not what I was getting at.
They have you disconnect to protect your airplane as the servos can do
too good a job of holding altitude. It wasn't lag they were worried
about.

Just as the question asks on the FAA exam. What do you do when
entering an area of moderate to severe turbulence?
The AP doesn't know the correct answer for that one and it's going to
hold altitude, and/or attitude even if it has to break something to do
it. (depends on the AP)

There really is such a thing as "too much of a good thing".

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"Roger" wrote in message
...
Ahhh... That's not what I was getting at.
They have you disconnect to protect your airplane as the servos can do
too good a job of holding altitude. It wasn't lag they were worried
about.

Yeah, there are a couple of issues there. The autopilot might command
surface deflections beyond what is safe for the control surface. Could rip a
surface off. And, as I already said, the autopilot could get into an
oscillation if it rides a rate limit.

Just as the question asks on the FAA exam. What do you do when
entering an area of moderate to severe turbulence?

Yup.

There really is such a thing as "too much of a good thing".

Roger that...uh..Roger.

Dick

Check developments in Israel. They have a lot of UAV's that have
systems in them that might fit your requirement right off the shelf?

Big John
`````````````````````````````````````````````````` ``````


On Fri, 25 Feb 2005 00:12:06 GMT, "Dick" wrote:

Sitting around the hanger and discussing the possibility of somehow using
off-the-shelf electronic/computer components or gadgits for semi-automatic
wing leveling on lightly loaded, short wingspans.

Not being computer guys, the current thought is that something should be out
there that is available cheaply and modifiable to use a simple wing
leveler.

Having heard someplace that automotive computers, as an example, sense data
millions of times leads us to believe that sensing the wing tip initial
movement and counteracting very very quickly would be a good thing.

As an example: One fellow pictured a rolling ball bearing inside a tube
somehow activating a magnetic switch which in turn pulses a dc linear motor
to operate the aileron minutely.

We are not sure how to detect the very earliest initial wing tip movement or
drive the small trim type motor and would appreciate some thoughts or site
recommendations to investigate.

Thanks, Dick