Gujarat Technological University 2011-4th Sem B.E Electrical Engineering BE- e- - Question Paper

Seat No.: _____ Enrolment No.______


GUJARAT TECHNOLOGICAL UNIVERSITY
B. E. Semester-IV- exam June- 2011
Subject code: 141701
Subject Name: Control Theory
Date: 10/06/2011 Time : 10:30 am to 1:00 pm
Total Marks: 70
Instructions:

1. Attempt all ques..
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a)
find state space representation of system shown in Figure-1
07
(b)
define Correlation ranging from transfer function and state-space equations with
suitable examples
07



Q.2 (a)
From block diagram shown in Figure-2, Draw the corresponding signal flow
graph and evaluate closed-loop transfer Function using Mason's gain Formula.

(b)
System one has transfer Function G
1(s)
=30 / 4S
2
+3 S+6 and system two has transfer
Function G
=2 / S+4 .Find cascade and parallel transfer Function for system 1
and system 2. Write MATLAB program to obtain cascade, and parallel transfer
Function from provided transfer Function.
2(s)
OR
(b)
describe subsequent Terms
(1) Transfer Function (2) State (3) Self Loop (4) Source Node
(5) Rise Time (6) Settling Time (7) Peak Time



Q.3
(a)
A system has subsequent transfer Function C
(s)
/R
=20 / S+10. Determine its
unit impulse ,step and ramp response with zero initial conditions. Sketch the
response.
(b)
The characteristic formula of Feedback control system is
S
4
+20S
3
+15S
2
+2S+K=0 .
(1) Determine range of K for system stability.
(s)
(1) Can the system be marginally stable ? If so, obtain the needed value of K and
Frequency of sustained oscillations.
OR
Q.3
A unity Feedback system has open loop Transfer Function,
G
(s)
H
(s)
= K (S+1) / S(S-1)( S
2
+ four S+16 ). find its Root Locus.
14



Q.4

For system having the open loop transfer function G(s)H(s) =10 / S(S+1)(S+10).
Determine the Stability of system by plotting the Bode Plot of the system.



OR

Q.4 (a)
define Liquid Level system and Derive Transfer Function of Liquid Level
system with Interaction.
07
(b)
Draw the Nyquist Plot for G(s)=1/S(S-1) and also Write MATLAB program for
it.



one
07
07
07
07
07
14
07

Q.5 (a)
What is analogous system? discuss Force-Voltage and Force-Current Analogy
With suitable Example
07
(b)
obtain Transfer Function of provided network in Figure-3.
07

OR

Q.5 (a)
discuss Standard Test signals
07

(b)
discuss Root Locus Technique Rules.
07

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two

Earning:   Approval pending.