Control System MCQs

Question 1

Which one of the following statements is true for gain margin and phase margin of two closed-loop system having loop transfer fuction G (s) H (s) and exp (--s) G (s) H (s)?

Accepted Answer

Both gain and phase margins of the two systems will be identical

Answer

Both gain and phase margins of G (s)H (s) will be more

Answer

Gain margins of the two systems are the same but phase margin of G (s) H (s) will be more

Answer

Phase margins of the two systems are the same but gain margin of G (s) H (s) will be less

Question 2

An effect of phase-lag compensation on servo system performanceis that

Accepted Answer

for a given relative stability, the velocity constant is increased

Answer

for a given relative stability, the velocity constant is decreased

Answer

the bandwidth of the system increased

Answer

the time response is made faster.

Question 3

Consider the system x(t) [1 1= 0 1 X(t) + b2 u(t)bi]c(t) = d1d2 X (t)The conditions for complete state controllability and complete observability is2u (s)C(s)e2t0

Accepted Answer

di> 0, b2 >0, bi and d2 can be anything

Answer

di> 0, d2 > 0, bi and b2 can be anything

Answer

b1 >0, b2 > 0, di and d2 can be anything

Answer

bi> 0, b2 >0, bi and d can be anything

Question 4

Which of the following motors would be suitable for use as servomotors? 1. Two-phase induction motor2.DC separately excited motor3.Single-phase induction motor.4.Universal motor5.Single-phase synchronous motor Select the correct answer using the codes given below :

Accepted Answer

1, 2 and 5

Answer

1, 2, 3, 4 and 5

Answer

2, 3 and 4

Answer

1 and 5

Question 5

In an open loop control system

Accepted Answer

both A and B above

Answer

control action is independent of the output

Answer

control action depends on human judgement automatically taken care of

Answer

Viscous friction coefficient is analogous to conductance

Question 6

In a closed loop control system

Accepted Answer

all of these

Answer

control action depends on the output and also on the input command

Answer

output signal is feedback to be compared with the reference signal

Answer

the accuracy is better than in open loop system

Question 7

A servomechanism is a feedback control system required to control

Accepted Answer

either A or B above

Answer

position

Answer

a derivative of position

Answer

none of the above

Question 8

Transfer function of a system is used to calculate

Accepted Answer

the output for a given input

Answer

the steady state gain

Answer

the time constant

Answer

the order of the system

Question 9

Poles are the complex frequencies of a transfer function where the response becomesIt is

Accepted Answer

infinite

Answer

zero

Answer

oscillatory

Answer

decaying