## January 6, 2012

### CONTROL SYSTEMS JNTU previous years question papers

Time: 3 hours Max Marks: 80

All Questions carry equal marks

1. Define and explain the following terms
(a) Characteristic equation
(b) Order of a transfer function
(c) Type of a transfer function
(d) Poles and zeros of a transfer function. [16]

2. Represent the following set of equation by a signal flow graph and determine the overall gain relating x5 and x1. [16]
x2 = ax1 + fx2
x3 = bx2 + ex4
x4 = cx3 + hx5
x5 = dx4 + gx2

3. (a) What are the types of controllers that are used in closed loop system? Explain them?
(b) The response of a system subjected to a unit step input is c(t) = 1 + 0.2e-60t -1.2e-10t
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. Explain the stability of the system from the root locus plot in the following situations with suitable examples?
(a) addition of open loop poles
(b) addition of open loop zeros. [16]

5. (a) Write a note on frequency domain specifications
(b) For a system the resonant peak is 1 dB an ?n = p10 r/s. Find resonant frequency.Also find the phase angle of closed loop transfer function at resonant frequency. [6+10]

6. (a) What is “Nyquist Contour”?(b) A system is given by
G(s) = 4s+1s2(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 compensator and draw pole-zero plot?
(c) Explain the different steps to be followed for the design of compensator using Bode plot? [3+3+10]

8. (a) Discuss the significance of state Space Analysis?
(b) Define state variables.
(c) Obtain the state variable representation of an armature controlled D.C Servomotor?