r05220205 Control Systems Augsep 2008

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Code No: R05220205 Set No. 1

5. Write short notes:

(a) Frequency domain specifications

(b) Stability analysis from Bode plots. [8+8]

6. (a) Define Polar plot.

(b) Explain how you can determine relative stability using polar plots.

(c) Sketch the polar plot of a system given by G(s) = 1s(1+s)(1+2s)

If the plot crosses

the real axis determine the corresponding frequency & magnitude. [2+4+10]

7. (a) What is compensation? what are the different types of compensators?

(b) What is a lag compensator, obtain the transfer function of lag compensatorand draw pole-zero plot?

(c) Explain the different steps to be followed for the design of compensator usingBode plot? [3+3+10]

8. (a) The system is represented by the differential equationy + 5y + 6y = uFind the transfer from state variable representation.

(b) Consider the RLC network shown in figure 8b. Write the state variable rep-resentation. [16]

Figure 8b

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II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008CONTROL SYSTEMS

( Common to Electrical & Electronic Engineering, Electronics &Communication Engineering, Electronics & Instrumentation Engineering,

Electronics & Control Engineering, Electronics & Telematics andElectronics & Computer Engineering)

Time: 3 hours Max Marks: 80Answer any FIVE Questions

All Questions carry equal marks

1. (a) Explain the effect of feedback on stability.(b) Explain the temperature control system concepts using open loop as well as

closed loop system. [8+8]

2. (a) Determine the transfer function C(s)R(s)

for the following block diagram (figure

2a)

Figure 2a

(b) Define various terms involved in signal flow graphs. [10+6]

3. (a) What are the types of controllers that are used in closed loop system? Explainthem?

(b) The response of a system subjected to a unit step input is c(t) = 1 + 0.2e60t1.2e10t

Obtain the expression for the closed loop transfer function? Also determine

the Un damped natural frequency and damping ratio of the system? [8+8]

4. Determine the values of k and b ,so that the system whose open transfer functionis G(s) = k(s+1)

s3+bs2+3s+1oscillates at a frequency of oscillations of 2 rad / sec. Assume

unity feed back. [16]

5. (a) Show that for a critically stable system the gain cross over frequency is equalto phase cross over frequency.

(b) The Gain Margin of a type-1, 2nd order system is always infinity. Justify.

(c) The Bode plots of a system is shown in figure 5c.

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1. (a) Obtain the transfer function for the following network Figure 1a:

Figure 1a

(b) Explain the effects of disturbance signals by use of feedback. [10+6]

2. (a) Determine the transfer function C(s)R(s)

for the following block diagram (figure

2a). [9+7]

Figure 2a

(b) Explain the properties of signal flow graphs.

3. (a) What is the difference between type and order of a control system? Explaineach with an example?

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(b) The figure 3b shows PD controller used for the system. Determine the valueofTd so that the system will be critically damped? Calculate its settling time?

[6+10]

Figure 3b

4. Sketch the root locus plot of a unity feed ?back system whose open loop T.F is

G(s) =K(s+9)

s(s2+4s+11) . [16]

5. Write short notes:

(a) Frequency domain specifications

(b) Stability analysis from Bode plots. [8+8]

6. (a) What is Nyquist Contour?

(b) A system is given byG(s) = 4s+1

s2(s+1)(2s+1)Sketch the Nyquist plot & hence determine the stability

of the system. [2+14]

7. (a) What is compensation? What are the different types of compensators?

(b) What is a lead compensator, obtain the transfer function of lead compensatorand draw pole-zero plot?

(c) Explain the different steps to be followed for the design of lead compensatorusing Bode plot? [3+3+10]

8. (a) Obtain the state model of the system shown in figure 8a.

Figure 8aConsider the state variables as i1, i2, v

(b) Obtain the state model of a field controlled motor? [8+8]

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1. (a) Derive the transfer function of the following network figure 1a by assumingR1=5M and R2 = 5M, C1=0.1F and C2=0.1F.

Figure 1a

(b) Find the transfer function of the following system show in figure 1b. [10+6]

Figure 1b

2. (a) Determine the overall transfer function relating C and R for the system whoseblock diagram is given (figure 2a).

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Figure 2a

(b) Explain the properties of block diagrams. [9+7]

3. (a) Explain about various test signals used in control system?

(b) Measurement conducted on a servomechanism shows the system response tobe C(t) = 1 + 0.2e60t1.2e10t, when subjected to a unit step input. Obtainthe expression For closed loop T.F., the damping ratio and undamed naturalfrequency of oscillations? [8+8]

4. (a) Explain the RH stability Criterion ?

(b) The open loop transfer function of a unity feed back control system is givenby G(s) = K

s(1+sT1)(1+sT2). Apply RH stability criterion, determine the value of

K in terms ofT1 and T2 for the system to be stable? [6+10]

5. (a) Derive the expressions for resonant peak & resonant frequency and henceestablish the correlation between time response & frequency response.

(b) Given = 0.7 & n = 10 r/s find resonant peak, resonant frequency & Band-width. [10+6]

6. (a) What is Nyquist Contour?

(b) A system is given byG(s) = 4s+1

s2(s+1)(2s+1)Sketch the Nyquist plot & hence determine the stability

of the system. [2+14]

7. (a) What is compensation? what are the different types of compensators?

(b) What is a lag compensator, obtain the transfer function of lag compensatorand draw pole-zero plot?

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(c) Explain the different steps to be followed for the design of compensator usingBode plot? [3+3+10]

8. (a) Obtain the state model of the system shown in figure 8a.

Figure 8aConsider the state variables as i1, i2, v

(b) Obtain the state model of a field controlled motor? [8+8]

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r05220205 Control Systems Augsep 2008