Seat No.: ________ Enrolment No.
___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER–IV (NEW) - EXAMINATION – SUMMER 2017
Subject Code: 2140307 Date: 14/06/2017
Subject Name: Control System and Analysis
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 Short Questions 14
1 In an open loop control system
A Output is independent of control input B Output is dependent
on control input
C Only system parameters have effect on the D None of the above
control output
2 A car is going at a constant speed of 50 km/h, which of the following is the
feedback element for the driver ?
A Clutch B Legs
C Needle of the speedometer D Steering wheel
3 The initial response when the output is not equal to input is called
A Transient response B Error response
C Dynamic response D None of these
4 The capacitance, in force-current analogy, is analogous to
A momentum B velocity
C displacement D mass
5 The type 0 system has ______ at the origin.
A no pole B net pole
C single pole D two poles
6 The time required for the response to rise from 10% to 90% of the final
value for over damped systems and 0 to 100% of the final value for under
damped systems is called the
A Rise time B Pickup time
C Settling time D Transient time
7 If poles of system are left side of s plane then system is ______________ .
A stable B Unstable
C Marginally stable D None
8 What is the output of Y(s)/X(s) = ___________
9 Write down forward paths of below system:
1
10 Give different examples of open loop system.
11 Give different examples of close loop system.
12 Find out poles and zeros of below given transfer function:
13 Find out order and type of below given transfer function:
14 An impulse function is a derivative of _________ function
A Parabolic B Step
C Ramp D Linear
Q.2 (a) Find transfer function of following system. Also find order and type of the system. 03
(b) Explain mason gain formula. 04
(c) Derive transfer functions for the following mechanical system. 07
OR
(c) Find out transfer function of below given Signal Flow Graph. 07
2
Q.3 (a) What is the output of Y(s)/X(s) = ___________ 03
(b) Explain Electrical-Mechanical Analogy. 04
(c) Consider the block diagram shown in the following figure. Simplify this 07
block diagram using the block diagram reduction rules and find out
C2(s)/R1(s).
OR
Q.3 (a) Find the stability of the control system having characteristic equation, 03
s4+2s3+s2+2s+1=0 using RH method.
(b) The close loop transfer function of a position control system is given by 04
By applying the Routh criterion discuss the stability of the closed loop
system as a function of K.
(c) Consider the block diagram shown in the following figure. Simplify this 07
block diagram using the block diagram reduction rules.
3
Q.4 (a) Define state variable using example. 03
(b) Define: Maximum overshoot and delay time of system. 04
(c) Draw the Bode Plot for following transfer function and find (a) Gain 07
Margin, (b) Phase Margin (c) Gain Crossover frequency (d) Phase
Crossover frequency. Also comment on stability.
OR
Q.4 (a) Define Gain margin and Phase margin. 03
(b) Define steady state error of system and derive it for different standard inputs and 04
TYPE 0 system.
(c) Obtain the phase and gain margins of the system shown in figure for the two 07
cases, where K = 10 and K = 100 with the help of bode plot. Also discuss about
the stability of same system with both gain.
Q.5 (a) Define damping factor ξ of system and explain system’s behavior for different 03
values of zeta(ξ).
(b) Draw the Nyquist plot of below given open-loop transfer function: Determine the 04
stability of the system using Nyquist criteria.
(c) Draw the root locus for following transfer function: 07
OR
Q.5 (a) Explain stable system, unstable system and marginally stable system with 03
reference to pole location in s plane.
(b) Draw Polar plots of following open loop transfer functions and also comment on 04
stability
(c) Draw the root locus for following transfer function: 07
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