Control Systems B.Tech Question Paper : vardhaman.org
College : Vardhaman College Of Engineering
Degree : B.Tech
Department : Electronics & Communication Engineering
Semester : IV
Subject :Control Systems
Document type : Question Paper
Website : vardhaman.org
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Vardhaman Control Systems Question Paper
Four Year B. Tech IV Semester Regular/Supplementary Examinations May – 2014
(Common to Electronics and Communication Engineering, Electrical and Electronics Engineering)
Date : 30 May, 2014
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
Related : Vardhaman College Of Engineering Hydralulic Machinery & Systems B.Tech Question Paper : www.pdfquestion.in/6334.html
Unit – I :
1. a) Distinguish between open loop and closed loop control system. Give any two examples for each. 7M
b) From the basic principle derive an expression for the transfer function between ?m(S) and control voltage of a two phase induction motor type A.C. servo motor. 8M
2. a) Define Transfer function. List out the properties, advantages and disadvantages of transfer functions. 5M
b) Write the differential equations for the mechanical system shown in fig1. Draw the electrical network and electrical analogue (FV, FI) giving clearly all the analogous quantities. Fig. 1 10M
Unit – II :
3. a) Draw a block diagram to describe the electrical circuit given in the fig.2 and determine the transfer function using block diagram reduction. 10M
b) Use Mason’s gain formula to find out Y5/Y1 for the signal flow graph shown in fig. 3 Fig. 3 5M
4. a) Obtain the transfer function of the lag network shown in fig. 4. Fig. 4 7M
b) For the system shown in fig. 5, determine I0(s)/Vi(s) by block diagram reduction technique. Fig. 5 8M
Unit – III :
5. a) A unit feedback system has G(s) = (40 (s+2)) / (s(s+1) (s+4)). Determine
i. Type of the system
ii. All error co-efficients
iii. Error for ramp input with magnitude 4 6M
b) A feedback control system has open loop transfer function G(s)H(S) = (K/(s(S+4)(S2 + 4S + 20))). Plot the root locus for K = 0 to ?. Indicate all the points on it. 9M
6. a) S6 + 4S5 + 3S4 – 16S2 – 64S – 48 = 0. Find the number of roots of this equation with positive real part, zero real part and negative real part. 6M
b) Open loop transfer function of unity feedback system is G(s) = (K/(1+Ts)s) where K and T are constants. Determine factor by which gain ‘K’ should be multiplied so that overshoot of unit step response be reduced from 75% to 25%. 9M
Unit – IV :
7. a) State the advantages and limitations of frequency domain approach. 5M
b) A unity feedback control system has G(S) = 10/S(S+1)(S+2). Draw Nyquist plot and comment on closed loop stability. 10M
8. a) State and explain Nyquist criterion. 5M
b) What are i)gain margin and ii) phase margin? Determine these two analytically for a system with G(S) H(S) = (1/(S(S+1)(S+(1/2)))) given that the gain crossover frequency is 0.82 rad/sec. Is the system stable? 10M
Unit – V :
9. a) Obtain a state model for the system described by
T(S) = (Y(s)/U(S)) = (2S3 + 7S2 + 12S + 8)/(S3 + 6S2 + 11S + 9) 7M
b) Write a note on the following:
i) Observability
ii) Controllability 8M
10. a) What is the significance of state transition matrix and list out its properties? 7M
b) A third order system has the coefficient matrix
A= 1 2 1 0 1 0 1 4 3 B = C 1 1 0
Determine the state transition matrix and output controllability 8M
B. Tech IV Semester Supplementary Examinations, December – 2013 :
Regulations: VCE-R11 :
Control Systems :
(Common to Electronics and Communication Engineering &
Electrical and Electronics Engineering)
Date : 21 December, 2013
Time : 3 Hours
Max. Marks : 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
Unit – I :
1. a) Define Control System and bring out the clear differentiation between the open loop and closed loop control systems with relevant examples. 8M
b) Determine the transfer function X2(s)/F(s) for the mechanical system shown in fig.1. fig.1 7M
2. a) Derive a transfer function for a simple closed loop control system.3M
b) For the following DC motor shown in fig.2, find the transfer function if Kb = Back e.m.f. constant, KT = Torque constant, Ks = Spring constant and J = moment of Inertia.
Unit – II :
3. a) Consider the system shown in fig.3. Simplify this diagram using block diagram reduction technique.
b) Find C/R for the graph shown in fig.4 using Mason’s gain formula. 7M
4. a) Find the transfer function of the given network shown in fig.5, using Mason’s gain formula. 7M
b) Use block diagram reduction method to obtain the equivalent transfer function from R to C of the fig.6 shown below.8M
5. a) The system given in fig.7 is a unity feedback system with minor feedback loop. In the absence of derivative feedback (a=0), determine the damping ratio and undamped natural frequency. Determine the constant ‘a’ which will increase damping ratio to 0.7. Find the overshoot in both the cases. 10M