Modern Control Engineering

Section 7–12 / Lag Compensation 509

Note that the zero and poles of the designed closed-loop system are as follows:

The dominant closed-loop poles are very close to the jvaxis with the result that the response

is slow. Also, a pair of the closed-loop pole at s=–0.1228and the zero at s=–0.1produces a

slowly decreasing tail of small amplitude.

Poles at s=-0.2859;j0.5196, s=-0.1228, s=-2.3155

Zero at s=-0.1

Outputs

1.4

0.6

0

1

1.2

0.4

0.2

0.8

t Sec

0105 15 20 25 30 35 40

Unit-Step Responses of Compensated and Uncompensated Systems

Compensated system

Uncompensated system

Figure 7–106
Unit-step response
curves for the
compensated and
uncompensated
systems (Example
7–27).

Outputs

20

8

0

12

18

4

2

16

10

14

6

t Sec

042 6 8 10 12 14 16 18 20

Unit-Ramp Responses of Compensated and Uncompensated Systems

Compensated system

Uncompensated system

Figure 7–107
Unit-ramp response
curves for the
compensated and
uncompensated
systems (Example
7–27).