
The case study in Section 3.7 involved the ascent of a diver subject to a vertical cable force f
c
.
A state-space model was formulated and repeated as follow s:
_
x
1
_
x
2
_
x
3
2
6
6
4
3
7
7
5
¼
010
0
mg
W
0
Kg 0 K
2
6
6
4
3
7
7
5
x
1
x
2
x
3
2
6
6
4
3
7
7
5
þ
0
g
W
0
2
6
6
4
3
7
7
5
[f
n
](4:713)
y
1
y
2
2
4
3
5
¼
100
g 01
"#
x
1
x
2
x
3
2
6
6
4
3
7
7
5
(4:714)
The input f
n
¼W gV f
c
is the net force (weight – buoyant force – cable force) acting on the
diver. The output y
1
is depth below the surface, and y
2
is the difference between the internal body
pressure of the diver and the local (same depth as diver) underwater pressure. The states x
1
, x
2
,
and x
3
are depth, velocity, and inte rnal pressure of the diver, respectively. The system ...