BEE Control System Principles 5

Question 1

In a block diagram, the signal flow from the output back to the summing junction is called:

Accepted Answer

Feedback path

Answer

The feedback path carries the measured output (or processed output) back to the summing junction to be compared with the reference input.

Question 2

For a unity-feedback system, the closed-loop transfer function T(s) = G(s)/[1+G(s)] has the sensitivity function S(s) equal to:

Accepted Answer

1/[1+G(s)]

Answer

The sensitivity function S(s) = 1/[1+G(s)] quantifies how output changes in response to disturbances or plant perturbations.

Question 3

Which statement about a minimum-phase system is correct?

Accepted Answer

All zeros are in the left-half plane

Answer

A minimum-phase system has all its zeros located in the left-half plane (open), giving the minimum possible phase lag for a given magnitude response.

Question 4

State feedback control with full state feedback u = -Kx can place all closed-loop poles arbitrarily if and only if the system is:

Accepted Answer

Controllable

Answer

Arbitrary pole placement via state feedback is possible if and only if the system is completely controllable (the controllability matrix has full rank).

Question 5

What is the bandwidth of a closed-loop system generally defined as?

Accepted Answer

The frequency at which the closed-loop magnitude drops to -3 dB below its DC value

Answer

Closed-loop bandwidth is defined as the frequency range over which the closed-loop magnitude stays within 3 dB of its low-frequency value.

BEE - Bachelor of Electrical Engineering Practice Test

BEE - Bachelor of Electrical Engineering Practice Test

BEE Control System Principles 5