Civil Engineering Reference
In-Depth Information
adjustment rules enable us to predict the parameters used in the precision or simplified precision models,
including their numerical values, for a specific combination of system dynamics and forcing function
signal bandwidth.
There are six rules, only the discussion of the first and the last will follow. The reader should keep in
mind that the adjustment rules have an empirical basis and should be used with care.
12.4.5.2 Rule #1: Equalization Selection and Adjustment
The first rule is the most important one, as it allows us to predict how humans will adapt to a
particular system, that is, what equalization parameters of the SPM are needed in order to follow
the COM.
The first rule states that the particular equalization is selected from the SPM such that the following
properties occur:
1. The system can be stabilized by proper selection of gain K
p
preferably over a very broad
range of K
p
2. Over a wide frequency range, near the cross-over region, the magnitude ratio
j
H
p
H
c
j
has an
“integrator-like” shape, that is, the ratio has approximately a
2
20 dB
/
decade slope
3.
j
1 is obtained at low frequencies to provide good low frequency closed-loop response to
system commands and suppression of disturbances
H
p
H
c
j
Figure 12.12 illustrates the choice of the pilot equalization parameters t
L
(lead) and t
I
(lag) such that,
for all three basic systems considered, the open-loop magnitude becomes “integrator-like” near the cross-
over frequency.
pilot
H
p
open loop
Y
OL
system
H
c
10
1
10
1
10
1
k
10
0
10
0
10
0
w
c
1/
t
I
10
−1
10
−1
10
−1
10
−1
10
0
10
1
10
−1
10
0
10
1
10
−1
10
0
10
1
10
1
10
1
10
1
k
/
s
10
0
10
0
10
0
w
c
10
−1
10
−1
10
−1
10
−1
10
0
10
1
10
−1
10
0
10
1
10
−1
10
0
10
1
10
1
10
1
10
1
k
/
s
2
10
0
10
0
10
0
w
c
1/
t
L
10
−1
10
−1
10
−1
10
−1
10
0
10
1
10
−1
10
0
10
1
10
−1
10
0
10
1
frequency, rad/sec
frequency, rad/sec
frequency, rad/sec
s
2
.
FIGURE 12.12 Pilot equalization when controlling the three basic systems k, k
s, and k
/
/
Search WWH ::
Custom Search