User`s guide

Yaw Damper for a 747 Jet Transport
9-15
The washout filter places azero at the origin, which constrains the spiral mode
pole to remain near the origin. We choose for a time constant of
three seconds and use the root locus technique to select the filter gain . First
specify the fixed part of the washout by
H = zpk(0,–0.333,1);
Connect the washout in series with the design model sys11 (relation between
input 1 and output 1) to obtain the open-loop model
oloop = H * sys11;
Hs()
s
sa+
------------=
a 0.333
=
k
ssa
+()⁄