Control system miscellaneous Easy Questions and Answers | Page - 10

Control system miscellaneous

Consider a system shown in the given figure
U(s) → 2 → C(s)
s

If the system is disturbed so that C(0) = 1, then C (t) for a unit step input will be

1. 1 + t
1. 1 – t
1. 1 + 2t
1. 1 – 2t

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The system represent an integrator, therefore, if a step function is applied, we get ramp output. This will be enhanced by the initial value present, i.e. by 1.
Thus, c (t) = 1 + 2t; t ≥ 0.

Correct Option: C

The system represent an integrator, therefore, if a step function is applied, we get ramp output. This will be enhanced by the initial value present, i.e. by 1.
Thus, c (t) = 1 + 2t; t ≥ 0.

A unity feedback control system has a forward path transfer function equal to
42.25
s²(s + 6.5)

The unit step response of this system starting from rest, will have its maximum value at a time equal to

1. 0 sec
1. 0.56 sec
1. 5.6 sec
1. infinity

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Step response transform is
42.25 = 1 + 6.5 - 1
s²(s + 6.5) s + 6.5 s² s

c (t) = e^-6.5t + 6.5 t u (t) – u (t)
At t → ∞, c (t) → ∞

Correct Option: D

Step response transform is
42.25 = 1 + 6.5 - 1
s²(s + 6.5) s + 6.5 s² s

c (t) = e^-6.5t + 6.5 t u (t) – u (t)
At t → ∞, c (t) → ∞

The feedback control system shown in the given figure represents a

1. Type 0 system
1. Type 1 system
1. Type 2 system
1. Type 3 system

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NA

Correct Option: D

NA

Consider a feedback control system with loop transfer function
G(s) H(s) = K(1 + 0.5s)
s(1 + s)(1 + 2s)

The type of the closed loop system is

1. zero
1. one
1. two
1. three

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Type of closed loop system having a feedback control system as
G(s) H(s) = K(1 + 0.5s) is one.
s(1 + s)(1 + 2s)

Correct Option: B

Type of closed loop system having a feedback control system as
G(s) H(s) = K(1 + 0.5s) is one.
s(1 + s)(1 + 2s)

The overall transfer function of the system in the given figure is

1. G
  1 - GH
1. 2G
  1 - GH
1. GH
  1 - GH
1. 2G
  1 - H

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Y₁ = U + X₂H
Y₂ = U + X₁H
and X₁ = GY₁ = GU + GX₂H
X₂ = GY₂ = GU + GX₁H
⇒ Y = X₁ + X₂ = 2 GU + GH (X₁ + X₂)
= 2 GU + GHY
⇒ Y = 2GU
1 - GH

⇒ Y = 2G
U 1 - GH

Correct Option: B

Y₁ = U + X₂H
Y₂ = U + X₁H
and X₁ = GY₁ = GU + GX₂H
X₂ = GY₂ = GU + GX₁H
⇒ Y = X₁ + X₂ = 2 GU + GH (X₁ + X₂)
= 2 GU + GHY
⇒ Y = 2GU
1 - GH

⇒ Y = 2G
U 1 - GH