REFLECTOR:Navaid Autopilot

[douglas holub]

One explanation might be that the thinner air adds some delay to the control
loop, just like a loose cable would. When the air is thinner, it will take
more aileron deflection to get the same roll force.
----- Original Message ----- 
From: "Chuck Jensen" <cjensen@dts9000.com>
To: <reflector@tvbf.org>
Sent: Friday, July 11, 2003 9:22 AM
Subject: RE: REFLECTOR:Navaid Autopilot


> Is there some reason the oscillation would be barely perceptible, if
present
> at all, at low altitudes but fairly aggressive at higher alt (+8,000)?
Does
> the higher altitude induce behavior that mimics, or aggravates, having
slop
> in the servo/control surface or incorrect sensitivity?
>
> Brian's comments about PIDs and their associated alogorithms being
> interesting creatures is certainly true.  We control heating in an
> industrial process with a heater that's driven by a controller that uses
> Fuzzy Logic.  I assume this is the same type of alogorithm application.
The
> closer the heater gets to the desired target, the slower it goes, until it
> stops right on the target without overshoot.  Then it stays there so
> consistently you'd think the indicator was stuck.
>
> As a side note, I understand my parents practiced the alogorithm method
but
> there was too much slack in the controls and that's why I'm here now.  But
> that's another story for another day.
>
> Chuck
> N27GV
>
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Jim Agnew
> Sent: Friday, July 11, 2003 9:18 AM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR:Navaid Autopilot
>
>
> The oscillation almost always occurs when there is slop in
> the control system between the servo and control surface.
> Have someone hold the aileron flush with the wing and move
> the servo arm back and forth and look for slop.  It doesn't
> take a lot.  If you don't have slop then the sensitivity of
> the unit (the dead zone) may have to be turned down.
>
> Jim
>
> --- Chuck Jensen <cjensen@dts9000.com> wrote:
> > I found the comments about the S-TEC and its oscillation
> > phenomena
> > particularly interesting.  I'm running a Naviad AP and
> > Wing Leveler and see
> > the same type of behavior, especially above approx.
> > 8,000'.  When the WL is
> > turned on, it rapidly oscillates L/R.
> >
> > I really didn't have a clue what was wrong and hadn't had
> > it looked at yet,
> > but now I wonder if this is, in fact, the same thing that
> > occurs in the
> > S-TEC.
> >
> > Has anyone had a similar behavior with the Navaid?
> > Solution?   Is this
> > problem likely similar/same as with the S-TEC?
> >
> > Chuck
> > N27GV
> > _______________________________________________
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>
> =====
> James F. Agnew
> Jim_Agnew_2@Yahoo.Com
> Tampa, FL
> Velocity 173 Elite Aircraft Completed
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>
> Visit the gallery!  tvbf:jamaicangoose
>