Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 4th Sem New 2141004 Control System Engineering Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?IV (NEW) EXAMINATION ? WINTER 2018
Subject Code:2141004 Date:05/12/2018
Subject Name:Control System Engineering
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Compare Open loop control system and Closed loop control system. 03
(b) Discuss standard Test signals used in control system. 04
(c) Determine the overall transfer function of the system shown in Fig. 1 using block
diagram reduction techniques.
07
Q.2 (a)
Define sensitivity of control system. Find S
G
T
for open and closed loop systems.
03
(b) Discuss force current (F-I) analogous system with analogous quantity. 04
(c) Draw signal flow graph of the system shown in Fig. 1 and find out ?? (?? ) ?? (?? ) ? of
the system using Mason?s gain formula.
07
OR
(c) Draw the equivalent mechanical network for given system as shown in Fig. 2.
Obtain differential equations describing the system and draw electrical network
using force voltage (F-V) analogy.
07
Q.3 (a) Discuss following transient response specification: Delay Time, Peak overshoot,
Settling Time
03
(b)
The overall transfer function of unity feedback control system is given by
?? (?? )
?? (?? )
=
10
?? 2
+6?? +10
. Find: 1. Position error constant 2. Velocity error constant 3. Acceleration
error constant
04
(c)
The loop transfer function of the system is: ?? (?? )?? (?? ) =
?? ?? (?? +1)(?? +3)
. Sketch the
root locus of the system and determine the value of ?? for marginal stability.
07
OR
Q.3 (a) Define following terms: State, State variable, State space 03
(b) Obtain the state transition matrix for the state model whose system matrix is given
by ?? = [
1 1
0 1
].
04
(c) Derive the expression for unit step response of underdamped second order system. 07
Q.4 (a) Discuss steady state error for a simple closed loop control system with negative
feedback.
03
(b) Find the range of ?? to make the unity feedback system stable using Routh?s
criterion with ?? (?? ) =
?? (?? +20)
?? (?? +2)(?? +3)
.
04
(c)
The loop transfer function of the system is: ?? (?? )?? (?? ) =
50
(?? +1)(?? +2)
. Using Nyquist
criterion, examine the closed loop stability of the system.
07
OR
Q.4 (a) State the various advantages and disadvantages of feedback with respect to control
system parameters.
03
(b) The characteristic equation of system is: ?? 4
+ ?? 3
+ ????
2
+ ?? + 1 = 0. Find kmar
and ? at kmar.
04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?IV (NEW) EXAMINATION ? WINTER 2018
Subject Code:2141004 Date:05/12/2018
Subject Name:Control System Engineering
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Compare Open loop control system and Closed loop control system. 03
(b) Discuss standard Test signals used in control system. 04
(c) Determine the overall transfer function of the system shown in Fig. 1 using block
diagram reduction techniques.
07
Q.2 (a)
Define sensitivity of control system. Find S
G
T
for open and closed loop systems.
03
(b) Discuss force current (F-I) analogous system with analogous quantity. 04
(c) Draw signal flow graph of the system shown in Fig. 1 and find out ?? (?? ) ?? (?? ) ? of
the system using Mason?s gain formula.
07
OR
(c) Draw the equivalent mechanical network for given system as shown in Fig. 2.
Obtain differential equations describing the system and draw electrical network
using force voltage (F-V) analogy.
07
Q.3 (a) Discuss following transient response specification: Delay Time, Peak overshoot,
Settling Time
03
(b)
The overall transfer function of unity feedback control system is given by
?? (?? )
?? (?? )
=
10
?? 2
+6?? +10
. Find: 1. Position error constant 2. Velocity error constant 3. Acceleration
error constant
04
(c)
The loop transfer function of the system is: ?? (?? )?? (?? ) =
?? ?? (?? +1)(?? +3)
. Sketch the
root locus of the system and determine the value of ?? for marginal stability.
07
OR
Q.3 (a) Define following terms: State, State variable, State space 03
(b) Obtain the state transition matrix for the state model whose system matrix is given
by ?? = [
1 1
0 1
].
04
(c) Derive the expression for unit step response of underdamped second order system. 07
Q.4 (a) Discuss steady state error for a simple closed loop control system with negative
feedback.
03
(b) Find the range of ?? to make the unity feedback system stable using Routh?s
criterion with ?? (?? ) =
?? (?? +20)
?? (?? +2)(?? +3)
.
04
(c)
The loop transfer function of the system is: ?? (?? )?? (?? ) =
50
(?? +1)(?? +2)
. Using Nyquist
criterion, examine the closed loop stability of the system.
07
OR
Q.4 (a) State the various advantages and disadvantages of feedback with respect to control
system parameters.
03
(b) The characteristic equation of system is: ?? 4
+ ?? 3
+ ????
2
+ ?? + 1 = 0. Find kmar
and ? at kmar.
04
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2
(c)
The open loop transfer function of the system is: ?? (?? )?? (?? ) =
10
?? (?? +1)(?? +10)
.
Determine the stability of the system by plotting the Bode plot of the system.
07
Q.5 (a) Explain PI controller with the help of diagram. 03
(b) Explain the Lead Compensator with its transfer function. 04
(c) Derive the state variable equation ?? ? = ???? + ???? and ?? = ???? + ???? . Also draw
the state diagram.
07
OR
Q.5 (a) Discuss Nyquist stability criterion. 03
(b) Discuss following terms with respect to frequency response: Gain Margin, Phase
Margin, Gain crossover frequency, Phase crossover frequency
04
(c) Discuss steps to design a Lag Compensator using Bode plot method. 07
Fig. 1 (for Q.1 C & Q.2 C)
Fig. 2 (for Q.2 C OR)
*************
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This post was last modified on 20 February 2020