Question Bank Control Engg 6th sem

7/29/2019 Question Bank Control Engg 6th sem

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rFACUTTY OF ENGINEERING, DAYATBAGH EDUCATIONAL IN TITUTE, AGRA

quEsTtoN BANK ( 20 _ 20 )

EEM.6O8 CONTROL ENG INEERING

UNIT-I

1. Define open loop and closed loop control system with suitable examples.

2' Why feedback is required and why a negative feedback is mostly used? Explain.

3. List the major advantages and disadvantages of open loop control system.

4. List the major advantages and disadvantages of closed loop control system.

5. obtain the transfer function of the mechanical system shown in Fig. 1-.

il K,'+al

R h-7 1

M1

rL

MLI {r

F- Lb)

+j

F3" ,

7. Write the differential equations governing the behavior of the mechanical system shown in fig.

3. Obtain an analogous electrical circuit based on Force-Voltage analogy.

2-

6. Obtain the transfer function of the mechanical system shown in Fig. 2.

FJ'r

t

.2.5



e

f8. Write the differential equations governlnt the behavior of the mec[4anical system shown in fig.

4. Obtain an analogous electrical circuit based on Force-Current analogy'

FL

I

-)

-*yA-l

A

t?'a2-

kL\

Mr M2d".

For the system shown

function.

in Fig.5 write the differential equations and hence derive the transfer

AZ

2Lr

trLE3.s

10. Obtain the transfer function of the mechanical

dbtrin their electrical analog.

systems shown in Fig. 6 (a) and Fig. 6(b). Also

ft.4

9.

vz- I(\z-

Mz

Ir

14r

k)

t-o '"tr Lk)

t.,ro Firllra.'a

Fg . 6col

L1. Write Laplace transform equations

Force-Voltage electrical analog.

FS 6 Cl")

for the mechanical system shown in Fig.7 and obtain its

r*' F--tr Lk)

trLtsJ



e

€12. Prove that the electricaland mechanicalsystems shown in Fig. g arepnalogous.

-T

t9c

Cy

frs.8

ecr)

F'6 '1

14' simplify the block diagram shown in Fig. 10. obtain the transfer function c(s)/R(s).

,Q.LF)

Rt tC6

L5. Reduce the

function.

block diagram

XA

cqa)

and derive its tra nsfe r

++

%.,o

in Fig. 11 into its canonical form

13' Reduce thebrock diagram shown in Fig, 9 into its canonicarform.

%"'



f;

16. Derive the transfer function C(s)/R(s) of the block diagram shown in Fig.12

Eg'1217. Obtain the transfer function C(s)/R(s) of the block diagram shown in Fig.13

acl/ 4cf )

RrCF)

shown in Fig. 14. Determine the

and Cr (s)/Rz(s) !R1(s)=Q

crCh )

62Cf) R,z(A)

Fr't4

19. Whatis Mason's Gain Formula? Explain its each terms.

20. Obtain the closed loop transfer function for the graph shown in Fig. 15 using Mason's Gain

Formula. I

R,c t^,)

Fq.l3<-)

1-8. A multi variable system with two inputs and two outputs is

following:

cf(s)/-Rr(s)! R2(s)=0, cz(s)/Rr(s) ! R2(s)=6, cz(s)/Rz(s) !R1(s): 0,

R-

4t 4z

-l trr3'rf

C-



21. Find the closed

Formula.

,.23. Find the closed

Formula.t

loop transfer function for the graph

Q4

loop transfer function for the graph

fr''t

€shown in Fig. 16 using Mason's Gain

t

trl.t7

shown in Fig. 18 using Mason's Gain

Lc.

Frg . lA

22. Using Mason's Gain Formula, evaluate the closed loop transfer function for the graph shown in

Fig.1'7.

Qt-4z

^H7

c-R



fJ

I.

2.

UNIT-II

Define the following terms in reference to a first order system and show them on a response

curve. (a) Delay Time (b) Rise Time and (c) Settling Time. a

Define the following terms in referenceto

asecond order system and show them on a response

curve. (a) Delay Time (b) Rise Time (c) Peak Time (d) Maximum Overshoot and (e) Settling Time.

3, Explain Transient response, Steady state response and steady state error.

4. Define stability, transient stability and steady state stability. Explain absolute stability and

relative stability,

What is the effect of damping on the response of a second order system? Explain the type of the

response of a second order system for a damping ratio equal to (a) 0, (b) 1, (c) greater than t

and (d) less than L.

What are the different types of standard test signals available to us? How different inputs in a

mechanica'l system are correlated with them? Explain.

Obtain the unit step response of a unity feedback control system with open loop transfer

4function given by G(st -

"-s(s +5)

Consider the unity feedback system whose transfer function is G(s) . Obtain the risef . s(s +r,)time, peak time, maximum overshoot and settling time for unit step input.

For the system shown in Fig. l-9, obtain the rise time, peak time, maximum overshot and settlingtime when the system is subjected to Unit step input. Assume On= 5 rad./sec. and (=0.6.

c(,A )

Fg,rr

10. For the system shown in Fig, 20, determine the value of gain 'K' and velocity feedback constant

Ku, so that the maximum overshoot in the unit step response is 0.2 and the peak time is l- sec.

With these values of K and Ku, obtain the rise time and settling time.

c(f)

5.

6

6

1-p + z\ N*)

"za



11. Consider the closed loop transfer function given by

C(s) _ u2"

ft

R(s) s+z(@ns+ a2n

Determine the values of 0)n and ( so that the system response to a step input will be

approximately 5 % overshoot and settling time of 2 secs.

L2. Consider a unity feedback system whose open loop transfer function is given by

( 0.4 s+1)G(s)=

s( s +0.6 )Obtain the response to a unit step input. What is the rise time and maximum overshoot.

13. Find the damping ratio of the system shown in fig. 2Q, if T= 3 seconds and the ratio K! = (2/91

rad.2/sec.

c(f)

14. Find the roots of the characteristics equations for the system shown whose transfer functions

are given below. Locate the roots in the 's - plane 'and indicate the stability of each system.t.L

a. G(s)H(s) =1, -r1, *n;

s(s+3)b. G(s)H(s) -

c. G(s)H(s) -

s(s+5)(s+8)9

s(s'+2)

L5.Forthecharacteristicsequationof aservosystemgivenby desa+?1s3+ a2s2+d3s*?q=0.

Determine the conditions which must be satisfied by the constants of the characteristics

equation for the system to be stable.

16. By means of the Routh-Hurwitz criterion, determine the stability of the system represented by

the following characteristics equations. For the system found unstable, determine the number of

roots lying in the right half of s-plane.a. sa+2s3+3 s2+4s+3=0

b. s4+2s3+s2+4s+2=O

c. ss + sa+ 3 s3 +9 s2+

16 s + 10 =0

d. s6 + ss + 5 sa+ 9 s3 + 8 s2+

6 s + 4 =0

17 The characteristics equations for certain feedback systems are given below. In each case

determine the range of 'K' for the system to be stable.

a. s3+ 3 Ks2+ ( K+ 2) ( s++) =6

b. sa +20 Ks3 + 5s2+ 10s+ 1-5 =0

c. sa +4s3+ 1-3 s 2+ 36s + K =0



fd

18 A unity feedback control system is charaeterized by equations of the following open loop

transfer functions. Using Routh-Hurwiz crlterion, calculate the range of 'K' for the system to be

stable.

a. G(s) =s(s + r)(s +2 )

K(s+13)b. c(s)

c(s)

s(s+3)(s +z)K(s+5)(s+40)

s3(s +200)(s+1000)

Unit-lll

1.. What is a Bode plot? Why this plot is drawn? Explain.

2. Explain in detail the procedure for drawing a Bode plot.

3. Why semi-logarithmic graph sheet is used to draw Bode plots? Explain.

4. What are the in formations obtained from the Bode plots? Explain.

5. Define Gain Margin, Phase Margin, Gain Cross-over Frequency, Phase Cross-over frequency and

corner frequency. What should be the range of gain margin and phase margin for a system to be

stable?

6. Draw the bode plots of a unity feedback system given by

G(s) =2504

s(s2+50.5s+L72) , where 4=200

7. Construct the Bode plot for the open loop frequency response function given by

4el+)

go), (r+f)cr*frt8j Construct the bode plots and determine the gain margin and phase margin for the system whose

open loop frequency response function is given below.

GH (ior)- - - \r --l (t+i.UD1z)z (l+j(l))

9. Construct the bode plots and determine the gain margin and phase margin for the system whose

open loop frequency response function is given below.

GH(jc^r)

-10. Sketch the Bode diagrams of the following transfer functions

GH(jo) -

Tr>72>0

T1>T2 >0

11. What is Nyquist Criterion? Explarn.

12. What is principal of argument? Give logical proof of this principle.

j|,D(r+ja / +) (r+jr,r/o.s)



f

l

2.

Unlt-lv

1 . Draw the loci of the roots of the following equation:

e

Consider the equation G(s)H(s) =

Draw the comPlete root locus of

K(s+3)function :G(s) - r(t + 5)(s + o)(s2 +2s + 2)

6.rrG(s)-#,asymPtotes.

7. Find the breakaway points for G(s)

8. Find the breakaway points for G(s) -

e. Find the breakaway points for G(s) =

L0. Draw the complete root loci of the control

G(s)H(s) - s(s + 1)(s +s )

s(s2+4s+13)

the system represented by characteristics

' equation s (s + 4) ( s*2) + K=0

+ . r*ptrin in oetait all the steps for drawing the root locus of a given system'

5: Draw the complete root loci of a unity feedback system with forward transfer

find the number, centroid and the angle of

(s+2)(s++)system rePresented by the block diagram snown

below.6 F,g.zz)CC

F),,

RCF)

8.. zzL)

Unit-V

1. Discuss the need for a compensator and exprain in brief about different types of compensator'

z. Describe the construction and working of a hydrauric amprifier. Hbw it can be converted into a

hydraulic servomotor? Derive the transfer functions of both'

3. Derive the transfer function of (a) Field controlled and (b) Armature controlled d' c' motor' Draw

their respective block diagrams representations'

4. Describe the principre and working of AC servomotor. Arso exprain its apprications in control

5. ffit n" working and applications of synchros in control system applications'

6. Explain the uses of potentiometerin control system applications'

9

-K

=::i

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Question Bank Control Engg 6th sem