Autopilot Kanardia, Руководство по установке

Страница: 36 / 52

Autopilot Installation Manual 6.1 Elevator
6.1.2 Vertical speed tune
After successful tuning the pitch control loop the operator should proceed
with tuning the vertical speed loop. The basic operation is similar to the
one we described in pitch tuning section. The operator should set the initial
controller parameters and the aircraft shall be trimmed and in level flight. If
the aileron axis is not tuned the pilot must maintain the aircraft leveled in
roll axis.
The operator shall tune the
P-term
first then move to
I-term
and tune
D-term
as a last parameter. Example tuning process of vertical speed loop is given
in figure 18.
P-term We start by tuning the
P-term
. Set the
I-term
to maximum value
and
D-term
to 0. Please remember that is best if you start with low
P-term
and then gradually increasing it, until you reach wanted response. A good
start value for VS loop is 0.01.
By tuning the
P-term
the operator must achieve pretty confident response of
the aircraft to the step change of the reference vertical speed. Do not worry
if the aircraft pitches down after initial pitch up reaction. This is normal and
it is related to the loss of airspeed. The tuning of
I-term
should handle this
situation.
If the aircraft starts to oscillate with large amplitude around pitch axis the
P-term is too high. You will have to decrease it to the half of the current
value.
Problems In case that it is impossible to tune the autopilot there is a
great chance that you are experiencing one of the basic controller problems
described in 5.4.
However in the VS loop there is another problem that could be present. The
vertical speed control loop is using measured vertical speed as a feedback
value. The vertical speed in Kanardia instruments is measured as a derivative
of a static pressure. If the aircraft is using cabin static pressure connection or
the pito-static tube located under the wing, static pressure will change rapidly
with the change of the aircraft angle of attack. With bad static pressure
connection autopilot will be unable to control vertical speed correctly.
I-term With properly tuned
P-term
of VS loop we should enable
I-term
. Set it to initial value of 15s and test the response. Decrease the
I-term
36
©
Kanardia 2016-2020