SET -A
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
BATCH (2023-2027): II Year/ III SEM
EC3351-CONTROL SYSTEM (R-2021)
MODEL EXAMINATION
DATE: TIME: 3HRS TOTAL MARKS: 100
PART A:(10X2=20 Marks)
1.Distinguish between open loop and closed loop control. (C205.1, PO1)
2. What are the characteristics of negative feedback? (C205.1, PO1)
3. Give the steady state error to a various standard input for type-2 system. (C205.2, PO1)
4. Describe peak overshoot and settling time. (C205.2, PO1)
5. Define gain margin. (C205.3, PO1)
6. State Nyquist stability criterion for a closed loop system when the open loop system is stable.
(C205.3, PO1)
7.Define Relative stability. (C205.4, PO1)
8. What is centroid of root locus? How the centroid is computed? (C205.4, PO1)
9.what are the characteristics of lead compensation? When is the lead compensation employed?
(C205.5, PO1)
10. Draw the frequency plot of lag compensator. (C205.5, PO1)
PART: B (5x13 = 65 Marks)
11.(a) For the mechanical translational system shown in below figure 1. Determine
i) differential equations
ii) F-V analogous circuit
iii) F-I analogous circuit (13) (C205.1, PO1, PO2, PO3)
Or
11.(b) By using block diagram reduction technique. Find C(S)/R(S). (13) (C205.1, PO1, PO2,
PO3)
12.(a)(i) The unity feedback system is characterized by an open loop transfer function,
G(S)=K/[S(S+1)]. Determine gain K, so that the system will have a damping ratio of 0.5
for this Value of Determine setting time, peak over shoot and time to peak overshoot
for a unit step input. (13) (C205.2, PO1, PO2, PO3)
Or
12.(b) (i) The unity feedback system is characterized by an open loop transfer function,
G(S)=10/[S(S+2)]. Find the rise time percentage overshoot, peak time and settling for a
step input of 12 units. (13) (C205.2, PO1, PO2, PO3)
13.(a) The open loop transfer function of the system G(S)=1/[S(4S+1) (0.5S+1)]. Sketch the
polar plot and obtain the value of gain margin and phase margin
following figure. (13) (C205.3, PO1, PO2, PO3)
Or
13.(b) Plot the Bode diagram for the following transfer function and obtain the gain and phase
cross over frequencies. G(s) =10/[s(1+0.4s) (1+0.1s)]. (13) (C205.3, PO1, PO2, PO3)
14.(a) (i) The open loop transfer function of feedback control system is given by
G(s) =K/[s(s+2) (s+1)]. Using Routh criterion, determine the range of K and
frequency of oscillation of the system. (10)
(ii) Discuss the concept of BIBO stability. (3) (C205.4, PO1, PO2, PO3)
Or
14.(b) The open loop transfer function of feedback control system is given by
G(s) =K/[s(s+2) (s+4)]. Sketch the root locus plot for the above system and
determine the valve of K. (13) (C205.4, PO1, PO2, PO3)
15.(a) (i) Construct a state model for the system described by the differential equation.
d3y/dt3+6d2y/dt2+11dy/dt+6y+u=0. Also draw the block diagram representation
of the state model. (8) (C205.5, PO1, PO2, PO3)
(ii) Discuss the solution of homogeneous state equation. (5)
Or
15.(b) A discrete time system described by the difference equation
y(k+2) +5y(k+1) +6y(k)=u(k) and initial condition y (0) =y (1) =0; T=1s.
Determine the state model in canonical form. Also compute the state controllability of the
above discrete time system, (13) (C205.5, PO1, PO2, PO3)
PART: C(1x15 = 15 Marks)
16 (a) The transfer function of the system is given by T(s) =(S2+3S+3)/(S3+2S2+3S+1).
Draw the Signal Flow Graph for the given transfer function. (15) (C205.1, PO1,
PO2, PO3)
Or
(b) Determine the state representation of a continuous time LTI system with system function
G(s) =(3S+7)/(S+1) (S+2) (S+5). (15) (C205.5, PO1, PO2, PO3)
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APPROVED BY-
SET -B
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
BATCH (2023-2027): II Year/ III SEM
EC3351-CONTROL SYSTEM (R-2021)
MODEL EXAMINATION
DATE: TIME: 3 HRS TOTAL MARKS: 100
PART A: (10X2=20 Marks)
1. Define open loop control system (C205.1, PO1)
2. What is block diagram? What is the basis component of block diagram? (C205 1, PO1, PO2)
3. Define steady state error. What are the three-constant associated with a steady state error?
(C205.2, PO1.PO2)
4. Define Damping ratio. What is damped frequency of oscillator? (C205.2, PO1)
5. What is Bode plot? What is the main advantage of Bode plot? (C205.3, PO1)
6. Define corner frequency. (C205.3, PO1)
7. What is Nyquist contour? What are the two segment of Nyquist contour? (C205.4, PO1.PO2)
8. State the angle and magnitude criterion for root locus. (C205.4, PO1.PO2)
9. Mention the different canonical forms. (C205.5, PO1.PO2)
10. List the advantages of static variable analysis. (C205.5, PO1.PO2)
PART: B(5x13 = 65 Marks)
11.(a) For the block diagram of the system shown in figure. Apply block diagram reduction
technique. Determine the closed loop transfer function. (13) . (C205.1, PO1.PO2)
Or
11.(b)Write the differential equation governing the mechanical rational system shown in figure.
Draw the Electrical equivalent analogy circuit (current and voltage). (13) (C205.1, PO1.PO2)
12.(a) For a unity feedback control system, the open loop transfer function is
G(s) = [10(s+2)]/[s2(s+1)]. Find (13) (C205.2, PO1.PO2)
(1) the position, velocity, acceleration error constants.
(2) the steady state error when R(s) = (3/s) -(2/s2) +(1/3s3)
Or
12.(b) Derive the expression for the following time domain specifications with unit step input.
i) Rise time, (ii) Peak time (iii) settling time (iv) Peak over shoot (13) (C205.2, PO1.PO2)
13(a) From the Bode plot of the system with the following open loop transfer function.
Determine the gain crossover frequency, Phase crossover frequency, gain margin and
phase margin G(s) = 15/[(s+1) (s+3) (s+6)] (13) (C205.1, PO1.PO2)
Or
13(b) sketch the polar plot of unity feedback system with the following open loop transfer
function. Determine the gain margin and phase margin G(s) = 50/[s(s+1) (s+5) (s+10)]
(13) (C205.3, PO1.PO2)
14.(a) (i) Examine the stability of the system using Routh’s criterion for the characteristic
equation of a system given by s5+2s4+3s3+6s2+10s+15=0. (6)
(ii) Determine the stability of the following system using Routh’s criterion.
G(s)H(s) =1/[(s+2) (s+4)] (7) (C205.4, PO1, PO2, PO3)
Or
14.(b) The open loop transfer function of unity feedback control system is given by
G(s)H(s) =K/[s(s+4) (s2+4s+20)]. Sketch the root locus. (13) (C205.4, PO1,
PO2, PO3)
15.(a) A system is given by the state equation and output equation. Justify, whether the systems
is controllable. (C205.5, PO1, PO2, PO3)
Or
15.(b)Determine the state space model for the electrical system shown in the figure. (13)
(C205.5, PO1, PO2, PO3)
PART: C(1x15 = 15 Marks)
16 (a) Design a lead compensator for a unity feedback system with open loop transfer function is
given by G(s) =K/s(s+1) (s+5) to satisfy the following specifications. (i) Velocity error
constant, kv ≥ 50 and (ii) phase margin is ≥ 20. (15) (C205.2, PO1, PO2, PO3)
Or
(b) (i) Drive the transfer function of armature-controlled DC servo motor system. (7)
(ii) Find the transfer function C(s)/H(s) for the signal flow graph shown in figure.
(C205.1, PO1, PO2, PO3)
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