## Control Systems previous question papers JNTU

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

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?