
Nonlinear systems 77
0 1 2 3 4 5 6
0.26
0.28
0.3
0.32
x
1
0 1 2 3 4 5 6
2.1
2.15
2.2
2.25
Time
x
2
Nonlinear
Linearised
FIGURE 3.4: State response of the nonlinear system (3.18) and of its lineari-
sation to a small step change of β (from 0.23 to 0.2 6), applied at t = 1.
0 1 2 3 4 5 6
0
0.5
1
1.5
2
x
1
0 1 2 3 4 5 6
0.5
1
1.5
2
2.5
Time
x
2
Nonlinear
Linearised
FIGURE 3.5: State response of the nonlinear system (3.18) and of its lineari-
sation to a large step change of β (from 0.23 to 0.3 5), applied at t = 1.