Geology Reference
In-Depth Information
0
v
f t
( )
=
k x
( )
t
+
c x
( )
t
+
α
z
( , )
t x
(1)
= −
η
(
v
−
v
)
(4)
c
0
mr
mr
mr
c
c
a
where
η
is the time constant associated with the
first-order filter and
v
a
is the voltage supplied to
the current driver. The MR damper parameters
used in the study reported in this chapter are
given in Table 1.
n
−
1
n
z
= −
γ
x
z
z
−
β
x
z
+
Ax
(2)
mr
mr
mr
mr
mr
mr
where
x
mr
is the displacement at the damper loca-
tion;
z
mr
is the evolutionary variable, and
γ
,
β
,
n
,
A
are parameters controlling the linearity in
the unloading and the smoothness of the transition
from the pre-yield to the post-yield region. The
functional dependence of the device parameters
on the command voltage
v
c
is expressed as
INTELLIGENT FUZZY LOGIC BASED
CONTROL DESIGN
Zadeh (1965) introduced fuzzy set theory to treat
imprecision and uncertainty that is often present
in implementation of problems in real world.
Mamadani (1974), by applying Zadeh's theories
of linguistic approach and fuzzy inference, suc-
cessfully used the if-then rule on the automatic
operating control of steam generator. Since then
fuzzy control theory has been applied to a number
of linear and nonlinear systems.
Fuzzy logic control (FLC) is a simulation of
logical reasoning of human brain; it maps an in-
put space to a corresponding output space based
on fuzzy rules specified in if-then format known
as knowledge base. Fuzzy logic-based control
includes a fuzzification interface, an inference
engine and a defuzzification interface. For details
(
v
)
v
;
c v
(
)
c
c
v
α
=
α
+
α
=
+
c
a
b c
0
c
0
a
0
b c
k v
(
)
=
k
+
k v
0
c
0
a
0
b c
(3)
α γ
( )
are
estimated on the basis of minimizing the error
between the model-predicted force (
u
) and the
force obtained in the experiment (details are
given in Ali & Ramaswamy (2009b)). In addition,
the resistance and inductance present in the circuit
introduce a dynamics into this system. This dy-
namics of the electrical part has been accounted
for by the first-order filter on the control input
given by
The six parameters
c
,
k
,
,
,
,
A
0
0
Table 1. Parameter values for magnetorheological damper
Parameter
Value
Parameter
Value
1 95 10
5
3 94 10
5
α
a
.
×
α
b
.
×
Nm
-1
Nm
-1
A
-1
10
2
4 15 10
3
c
0
8 67
.
×
.
×
c
0
Nsm
-1
Nsm
-1
A
-1
7 51 10
2
3 46 10
3
k
0
.
×
.
×
k
0
Nsm
-1
Nsm
-1
A
-1
2
190
s
-1
η
n
2 85
.
β
5 42
.
γ
A
12 26
.
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