Aligarh College of Engineering & Technology, Aligarh B. Tech. (ME) IV-Semester, Sessional Test-ii (2014-15)

EMAC

Duration: - 2 Hrs. ( 8:40-10:40PM ) MM: 50

1. Attempt any three parts (3x5marks=15marks)

a) Define force-voltage analogy and force-current analogy for translational mechanical system and develop differential equation model for mechanical

system shown in fig.

b) Draw the f-i equivalent and f-v equivalent circuit.

c) Derive the transfer function Eo(s)/Ei(s) of the network shown below-

d) Distinguish between the open loop and closed loop control system

with suitable example.

e) Draw the mathematical expression and draw the characteristics for

the input test signals. Also write down their laplace transform.

3. Attempt any three parts (3x5marks=15marks)

a) Find the value of ξ and Wn for the system whose response is given in fig. &

hence write down the transfer function for it.

b) Comment about the stability for the system having characteristic equation-

01264222345

sssss

c) For the given system find the range of K, marginal value of K and frequency of

sustained oscillations- )256()2(

)()(22

sss

KsHsG

d) Draw the polar plot for the given system and comment about its stability.

)12)(1(

1)(

ssssG

4. Attempt any two parts (2x10marks=20 marks)

a) Draw the Bode Plot for the transfer function-)05.01)(25.01(

)125.01(50)(

sss

ssG

From the graph determine- i)- Gain crossover frequency

ii)-Phase crossover frequency iii)- Gain Margin iv)- Phase Margin

b) For a unity feedback system the open loop transfer function is given by-

)256)(2(

)()(2

ssss

KsHsG

Sketch the root locus and determine the breakaway point,the angle of

departure from complex poles and the stability condition.

c) Explain the P, PI and PID control mode. Write down their mathematical

equation and effects.