Modern Control Engineering

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Example Problems and Solutions 243

A–5–11. Consider the closed-loop system defined by

Using a “for loop,” write a MATLAB program to obtain unit-step response of this system for the

following four cases:

Solution.Definev^2 n=aand 2zvn=b. Then,aandbeach have four elements as follows:

a=[1 41636 ]

b=[0.6 2 5.6 9.6]

Case 4: z=0.8, vn= 6

Case 3: z=0.7, vn= 4

Case 2: z=0.5, vn= 2

Case 1: z=0.3, vn= 1

C(s)

R(s)

=

v^2 n

s^2 + 2 zvn s+v^2 n

Output

y(

t)

t(sec)

Unit-Step Response

0.6

0.4

0.2

0.8

1

1.2

1.4

1.6

1.8

0

0 2 4 6 8 10 12 14 16 18 20

Figure 5–58
Unit-step response
curve.