Modern Control Engineering

376 Chapter 6 / Control Systems Analysis and Design by the Root-Locus Method

t Sec

071 2 3 4 5 6 8 9 10

(a)

Outputs

0.4

0.8

0

1.2

0.6

1

0.2

Unit-Step Responses of Compensated and Uncompensated Systems

Uncompensated system

Compensated system

t Sec

071 2 3 4 5 6 8 9 10

(b)

Input Ramp and Outputs

2

4

0

6

3

5

1

7

8

9

10

Unit-Ramp Responses of Compensated and Uncompensated Systems

Uncompensated system has

steady-state error of 0.4

Compensated system has

steady-state error of 0.02

t Sec

35 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40

(c)

Input Ramp and Outputs

37.5

38.5

40

35

39.5

38

39

35.5

37

36.5

36

Unit-Ramp Response (35 t 40)

Uncompensated system

Compensated system

Figure 6–85

(a) Unit-step

responses of the

compensated and

uncompensated

systems; (b) unit-

ramp responses of

both systems; (c)

unit-ramp responses

showing steady-state

errors.

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