# Control Systems

## Trending Questions

**Q.**

What is the full form of DMP?

**Q.**The break away point of the root locus on the real axis for a closed-loop system with a loop gain

G(s)H(s)=K(s+10)(s+2)(s+5) lies

- between - 2 and origin
- between -2 and - 5
- between - 10 and −∞
- at −∞

**Q.**A unity feedback control system is characterized by the open-loop transfer function

G(s)=10K(s+2)s3+3s2+10.

The Nyquist path and the corresponding Nyquist plot of G(s) are shown in the figures below.

If 0<K<1, then the number of poles of the closed-loop transfer function that lie in the right -half of the s-plane is

- 0
- 1
- 2
- 3

**Q.**A unity feedback system has open loop transfer function G(s)=25s(s+6). The peak overshoot in the step-input response of the system in approximately equal to

- 5%
- 10%
- 15%
- 20%

**Q.**The open loop transfer function G(s) of a unity feedback control system is given as,

G(s) = K(s+23)s2(s+2)

From the root locus, it can be inferred that when k tends to positive infinity

- Three roots with nearly equal real parts exist on the left half of the s-plane.
- One real root is found on the right half of the s-plane
- The root loci cross the jω axis for a finite value of k : k ≠ 0.
- Three real roots are found on the right half of the s-plane.

**Q.**The open loop transfer function of an unity feedback open loop system is 2s2+6s+5(s+1)2(s+2). The characteristic equation of the closed loop system is

- 2s2+6s+5=0
- (s+1)2(s+2)=0
- 2s2+6s+5+(s+1)2(s+2)=0
- 2s2+6s+5−(s+12)(s+2)=0

**Q.**A system with the open loop transfer function:

G(s)=Ks(s+2)(s2+2s+2) is connected in a negative feedback configuration with a feedback gain of unity. For the closed-loop system to be marginally stable, the value of k is

- 5

**Q.**The forward transfer function of a unity feedback system is

G(s)=K(s2+1)(s+1)(s+2).

The system is stable for

- K < - 1
- K > - 1
- K < - 2
- K > - 1

**Q.**Consider the unit step response of a unity feedback control system whose open loop transfer function is

G(s)=1s(s+1)

The maximum overshoot is equal to

- 0.143
- 0.153
- 0.163
- 0.173

**Q.**The gain margin of a unity feedback control system with the open loop transfer function is

G(s)=(s+1)s2

- 0
- 1√2
- √2
- ∞

**Q.**

The open-loop transfer function of a unity-feedback control system is given by

G(s)=Ks(s+2)

For the peak overshoot of the closed-loop system to a unit step input to be 10% , the value of K is

- 2.8

**Q.**The unit impulse response of a unit feedback control system is given by: c(t)=−te−t+2e−t, (t≥0) the open loop transfer funciton is equal to

- s+1(s+2)2
- 2s+1s2
- s+1(s+1)2
- s+1s2

**Q.**The open loop transfer function of a unity feedback control system is given as G(s)=as+1s2. The value of 'a' to give a phase margin of 45∘ is equal to.

- 0.141
- 0.441
- 0.841
- 1.141

**Q.**A unity feedback system has the open loop transfer function,

G(s)=1(s−1)(s+2)(s+3)

The Nyquist plot of G(s) encircle the origin.

- Never
- Once
- Twice
- Thrice

**Q.**

The forward path transfer function of a unity negative feedback system is given by G(s)=K(s+2)(s−1)

The value of K which will place both the poles of the closed-loop system at the same location is

- 2.25

**Q.**The transfer function of a Zero-Order-Hold system with sampling interval T is

- 1s(1−e−Ts)
- 1s(1−e−Ts)2
- 1se−Ts
- 1s2e−Ts

**Q.**A unity-feedback control system has the open-loop transfer function G(s)=4(1+2s)s2(s+2) if the input to the system is a unit ramp, the steady-state error will be

- 0
- 0.5
- 2
- Infinity

**Q.**The open-loop transfer function of a plant is given as G(s)=1s2−1. If the plant is operated in a unity feedback configuration, then the lead compensator that can stabilize this control system is

- 10(s−1)s+2
- 10(s+4)s+2
- 10(s+2)s+10
- 2(s+2)s+10

**Q.**

A unity negative feedback system has the open-loop transfer function G(s)=Ks(s+1)(s+3)

The value of the gain K(>0) at which the root locus crosses the imaginary axis is

- 12

**Q.**The unit step response of a linear time invariant system is s(t)=(2−e−2t)u(t). The unit impulse reponse of the system is

- 2e−2t u(t)
- δ(t)+2e−2tu(t)
- e−2tu(t)
- δ(t)+e−2tu(t)

**Q.**The transfer function of a phase-lead compensator is given by

Ge(s)=1+3Ts1+Ts where T>0.

The maximum phase-shift provided by such a compensator is

- π/2
- π/3
- π/4
- π/6

**Q.**A unity feedback control system has an open-loop transfer function G(s)=Ks(s2+7s+12). The gain K for which s=−1+j1 will lie on the root locus of the system is

- 4
- 5.5
- 6.5
- 10

**Q.**Transfer function of a first order system is given byG(s)=1Ts+1

Impulse response of the system is

**Q.**The steady state error of a stable 'type 0' unity feedback system for a unit step function is

- 0
- 11+KP
- ∞
- 1KP

**Q.**The state space equation of a system is described by ˙x=Ax+Bu, y=Cx where x is state vector, u is input, y is output and A=[010−2], B=[01], C=[1 0]

The transfer function G(s) if this system will be

- s(s+2)
- s+1s(s−2)
- s(s−2)
- 1s(s+2)

**Q.**The phase cross-over frequency of the transfer function G(s)=100(s+1)3 in rad/s is

- √3
- 1√3
- 3
- 3√3

**Q.**An open loop system represented by the transfer function is

G(s)=(s−1)(s+2)(s+3)

- stable and of the minimum phase type
- stable and of the non-minimum phase type
- unstable and of the minimum phase type
- unstable and of the non-minimum phase type

**Q.**A closed loop system has the characteristic equation given by s3+Ks2+(K+2)s+3=0. For this system to be stable, which one of the following conditions should be satisfied?

- 0 < K < 0.5
- 0.5 < K < 1
- 0 < K < 1
- K > 1

**Q.**A closed loop system is shown in figure.

Range of K in which system is stable

- K > 0
- K < 12
- K > 12
- 0 < K < 12

**Q.**The asymptotic Bode plot of the transfer function

K/[1+(s/a)] is given in figure. The error in phase angle and dB gain at a frequency of ω=0.5 are respectively.

- 4.9∘, 0.97 dB
- 5.7∘, 3 dB
- 4.9∘, 3 dB
- 5.7∘, 0.97 dB