Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 5th Sem 2150909 Control System Engineering Previous Question Paper
Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?V (NEW) EXAMINATION ? WINTER 2020
Subject Code: 2150909 Date: 22/01/2021
Subject Name: Control System Engineering
Time: 10:30 AM TO 12:30 PM Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Describe the components and variables of biological control system involved in
03
walking in a prescribed direction.
(b) Write the difference between open loop and closed loop control system.
04
(c) Explain transfer function and write its advantages and disadvantages.
07
Q.2 (a) Name the analogous electrical elements in force-voltage analogy for the
03
elements of mechanical translational system.
(b) Can a signal flow graph be drawn for nonlinear system? State Mason's gain
04
formula.
Reduce the block diagram shown in Figure 1 to a single transfer function ()
07
(c)
()
using block diagram reduction technique.
Figure 1
Q.3 (a) Define the following terms
03
1) Delay time 2) Rise time 3) Peak time
(b) Distinguish between type and order of a control system.
04
(c) Find the steady-state errors for inputs of 5u(t), 5tu(t), and 5t2u(t) to the
07
system shown in Figure 3. The function u(t) is the unit step.
Figure 3
Q.4 (a) Define the following terms.
03
1
1) State 2) State variable 3) State vector
(b) Explain standard test signals used in control system.
04
(c) The closed loop transfer function of unity feedback control system is given by
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()
100
=
()
2+8+100
Determine
1) Damping ratio
2) Natural undamped resonance frequency
3) Percentage peak overshoot
Q.5 (a) What are the conditions to be satisfied for the Root locus to exist at any point in
03
the s-plane?
(b) Write a short note on the correlation between time and frequency responses.
04
(c) For the closed loop transfer function
07
10
() =
8 + 7 + 126 + 225 + 394 + 593 + 482 + 38 + 20
Check stability of the system. Find how many poles are in the right-half plane?
Using Routh-Hurwitz stability criterion
Q.6 (a) What is a Root locus? How can you tell from the Root locus if a system is
03
unstable?
(b) Explain how do you determine the gain crossover frequency and phase
04
crossover frequency from the Bode plot?
(c) The unity feedback system has
07
()() =
( + 2)( + 4)
Draw the rough sketch of the Root locus.
Q.7 (a) Define the Bode plot. What do you mean by an approximate Bode plot?
03
(b) Briefly explain about Polar plots.
04
(c) Sketch the Bode plots for the transfer function given below:
07
200
()() =
( + 2)( + 10)
Q.8 (a) By applying the final-value theorem, find the final value of f(t) whose Laplace
03
transform is given by
1
() =
( + 1)
(b) State Nyquist stability criterion. Why the Nyquist criterion is called a
04
frequency response method?
(c) Derive Overall transfer function of Field controlled DC motor.
07
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This post was last modified on 04 March 2021