Biomedical Engineering Reference
In-Depth Information
In this figure, the closed-loop transfer function of the system is:
K
p
.a(s)
b(s)
a(s)
b(s)
⇒
H (s)
=
G(s)
=
(11.10)
+
K
p
.a(s)
In the experiments, we set
K
p
= 1. Therefore
H
(
s
) can be easily derived from
G
(
s
):
a(s)
b(s)
86
a(s)
b(s)
=
86
G(s)
=
a(s)
=
86
⇒
H (s)
=
(11.11)
+
s
2
+
23.4
s
+
s
2
+
23.4
s
11.6.2 Verifying the Identification Results
To verify the identification results obtained in the frequency domain, a step input is
applied to the system and the time response of the position of the linear actuator is
checked. Figure 11.13 shows the response of the system to a step input.
In this figure, the overshoot can be calculated as:
0.7
5
OS
=
100
=
14%
(11.12)
And
ζ
can be calculated:
−
ln
(
0.14
)
π
2
ζ
=
=
0.53
(11.13)
(
ln
(
0.14
))
2
+
Figure 11.13
The response of the system to a step input
