Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem New 2151908 Control Engineering Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? WINTER 2018
Subject Code:2151908 Date:04/12/2018
Subject Name:Control Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Draw a generalized closed loop feedback system with its components. 03
(b) Define transfer function. List important characteristics of transfer function. 04
(c) Explain Force-Voltage and Force-Current analogy. 07
Q.2 (a) Define:
a) Control variable
b) Manipulated Variable
c) Process
03
(b) Simplify the block diagram shown in figure-1. 04
(c) In a liquid-level system assume that the outflow rate Q m
3
/sec through the
out flow valve is related to the head H m by ?? = ?? ??? = ?? . ???? ??? .
Assume that when the inflow rate Qi is 0.015 m
3
/sec the head stays
constant. At t = 0 the inflow valve is closed and so there is no inflow for t
?0. Find the time necessary to empty the tank to half the original head. The
capacity C of the tank is 2 m
2
.
07
OR
(c) Simplify the block diagram shown in figure-2. Obtain the transfer function
relating C(s) and R(s).
07
Q.3 (a) Explain the ramp input mathematically and graphically. 03
(b)
For the following system:?? (?? ) =
?? (?? + ???? )
?? (?? + ?? )(?? + ?? .???? )
?? Find the value of k to
limit the steady state error to 10% for input t.
04
(c) Draw the signal flow graph for the following setoff algebraic equation:
y
2
= ay
1
? gy
3
; y
3
= ey
2
+ cy
4
; y
4
= by
2
? dy
4
. Hence find the gain.
07
OR
Q.3 (a) Discuss the effect of time constant on first order system response for unit
step input.
03
(b) Give four points difference between Block diagram method and Signal
Flow Graph method.
04
(c) Find the time response of a second order system for Unit step Response. 07
Q.4 (a) Enlist limitations of Routh?s stability criterion. 03
(b)
Prove that steady state error for Step input is gives as ?? ????
=
?? ?? + ?? ?? , Kp =
error constant
04
(c) Using Routh criterion, discuss about the stability for the system having
characteristics equation is given as 3s
7
+9s
6
+ 6s
5
+ 4s
4
+ 7s
3
+ 8s
2
+ 2s + 6
= 0
07
OR
Q.4 (a) Write the draw backs of hydraulic system. 03
(b) Plot the root locus for a unity feedback system whose forward transfer
function is ?? (?? ) =
???? (?? + ?? )
?? (?? ? ?? )
04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? WINTER 2018
Subject Code:2151908 Date:04/12/2018
Subject Name:Control Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Draw a generalized closed loop feedback system with its components. 03
(b) Define transfer function. List important characteristics of transfer function. 04
(c) Explain Force-Voltage and Force-Current analogy. 07
Q.2 (a) Define:
a) Control variable
b) Manipulated Variable
c) Process
03
(b) Simplify the block diagram shown in figure-1. 04
(c) In a liquid-level system assume that the outflow rate Q m
3
/sec through the
out flow valve is related to the head H m by ?? = ?? ??? = ?? . ???? ??? .
Assume that when the inflow rate Qi is 0.015 m
3
/sec the head stays
constant. At t = 0 the inflow valve is closed and so there is no inflow for t
?0. Find the time necessary to empty the tank to half the original head. The
capacity C of the tank is 2 m
2
.
07
OR
(c) Simplify the block diagram shown in figure-2. Obtain the transfer function
relating C(s) and R(s).
07
Q.3 (a) Explain the ramp input mathematically and graphically. 03
(b)
For the following system:?? (?? ) =
?? (?? + ???? )
?? (?? + ?? )(?? + ?? .???? )
?? Find the value of k to
limit the steady state error to 10% for input t.
04
(c) Draw the signal flow graph for the following setoff algebraic equation:
y
2
= ay
1
? gy
3
; y
3
= ey
2
+ cy
4
; y
4
= by
2
? dy
4
. Hence find the gain.
07
OR
Q.3 (a) Discuss the effect of time constant on first order system response for unit
step input.
03
(b) Give four points difference between Block diagram method and Signal
Flow Graph method.
04
(c) Find the time response of a second order system for Unit step Response. 07
Q.4 (a) Enlist limitations of Routh?s stability criterion. 03
(b)
Prove that steady state error for Step input is gives as ?? ????
=
?? ?? + ?? ?? , Kp =
error constant
04
(c) Using Routh criterion, discuss about the stability for the system having
characteristics equation is given as 3s
7
+9s
6
+ 6s
5
+ 4s
4
+ 7s
3
+ 8s
2
+ 2s + 6
= 0
07
OR
Q.4 (a) Write the draw backs of hydraulic system. 03
(b) Plot the root locus for a unity feedback system whose forward transfer
function is ?? (?? ) =
???? (?? + ?? )
?? (?? ? ?? )
04
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2
(c)
A unity feedback control system has ?? (?? ) =
?? (?? + ???? )
?? (?? + ?? )(?? +?? )
Using Routh?s
criterion calculate the range of k for which the system is
a) Stable
b) Has its closed loop, poles more negative than -1.
07
Q.5 (a) Write three rules for drawing Signal flow graph. 03
(b) With the help of neat diagrams, explain how the direction control valves
are classified.
04
(c) Draw the schematic diagram of Hydraulic PID controller. Explain its
working and derive its transfer function.
07
OR
Q.5 (a) Explain FRL unit. 03
(b) Write the comparison between a Pneumatic system and Hydraulic system. 04
(c) Draw the schematic diagram of Pneumatic PI controller. Explain its
working and derive its transfer function.
07
Figure-1
Figure-2
*************
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This post was last modified on 20 February 2020