Page 172 - MATLAB an introduction with applications

Control Systems ——— 157

ans =
Mag
ans =
–3.0032
ans =
BW
wBW =
9.7900
Bandwidth = 9.79, Phase margin = 53.892, Damping ratio = 0.59, Percent overshoot = 10.0693, Settling
time = 0.804303, Peak time = 0.461606
The step response is shown in Fig. E3.13(b)

Step Response
1.4

1.2

1

Amplitude 0.8

0.6

0.4

0.2

0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Time (sec)

Fig. E3.13 (b)
(b) Likewise, for this problem
>> G = zpk ([–1 –7], [0 –2 –4 –8], 25)
>> G = tf (G)
The following Bode plot and step response are obtained [see Figs. E3.13(c) and (d)].
Zero/pole/gain:
25(s + 1)(s + 7)
( ss + 2)(s + 4)(s + 8)

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