RTU 2016 Question Paper Semester VI Electronics and Communication Engineering Control Systems

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RollNo. Total No of Pages: tr
6E6055
B. Tech. VI-Sem. (Main/Back) Exam., ApriUM ay-2016
Electronics & Communication Engineering
6EC5A Control Systems

Time: 3 Hours Maximum Marks: 80
Min. Passing Marks (Main & Back): 26
I nstructians to Candidqte s : -

Anempt any five quesfions, selecting one question from each unit. All
Questions carry equal mnrks. schematic diagrams must be shown
wherever necessary. Any data you feel missing may suitably be assumed
and stated clearly.
units of quantities used"/ calculated must be stated crearly.
Use of following supporting material is permitted during examination.
(Mentioned inform No. 205)
1. NIL 2. NIL

UNIT.I
Q.1 (a) Determine the transfer function of the following electrical network. l8l

R

ti

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(b) Find the transfer function of the system whose singre flow graph is below.
tsl

OR
Q.1 (a) What is closed loop transfer function of a system with positive
feedback?
Explain, what is the effect on stability?
t8l
(b) Simplify the block diagram shown in fig.
t8l

UNIT.II
Q.2 (a) A unity feedback control sysrem has G (S) = 1

The inPut to the sYstem is
-
s (s+ A'
given by T (t) = 2t + 3t + 3t3. Determine the general
error coefficient and steady
state error.

Explain force - voltage & force
- current analogy with complete details. tg]
(b) Determine the stability of system
56 + Ss + 5Sa + 3S3 +ZS2-45 _ g
=0 t8l
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16760l

OR
I
Consider the system having open loop transfer function G
(S) =
Q.2 (a) S (S+1)

Calculate rise time, peak time, peak overshoot and settling
time. t8l

(b) What is time response of the system when it is exited by unit step
I/P? t8l

R(s) c(s)

UNIT.III
Q.3 (a) The open looP transfer function of a unity feedback control system is given
below.

(s + 0.2s)
s2 (s +1) (s + 0.5)

Determine closed loop stability and nyquist criteria' l8l

(b) Find out time response of second order sysem for step input and also all
parameters. t8l
OR

Q.3 (a) Discuss stability of a system by root locus techniques.
G(s) = --=+ (s+5)
H(S)=1 t8l
s2 1s+2)
-, of root locus plot'
(b) Explain the salient features t8l

Q.4 (a) The open loop transfer function of a feed back control system
is

c(s)H(s) = S,l.#.rsD
Draw Bode - plot & find K for gain margin 20dB t8l

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(b) Determine following terms:
(i) PhasecrossoverfrequencY tzl
(ii) Phase margin t2)

(iii) Gain cross over frequency 12)

(iv) Gain margin t2)

OR
Q.4 (a) Sketch Bode - plot for -
1000
G(S) = (1+.2S) (1+.002S)
t8l

(b) Consider -
K
S(S1+1)

Determine values of K & T with Mp = 25Vo andW, = 8 rad / second. t8l

UNIT.V
Q.5 Compare lag, lead and lead - leg compensating network in detail. t16l
OR
Q.5 (a) What is controller? Explain PID controller with effect of P, I, D individually. t8l
O) Obtain state model for the transfer function
Y(S) _ 6(S+3) (S+2.5) t8l
U(S) (S+2) (S'?+45+5)

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