BME Control Systems 2

Question 1

The Routh-Hurwitz criterion determines system stability by:

Accepted Answer

Examining the signs of elements in the Routh array without computing roots

Answer

Plotting the frequency response of the open-loop transfer function

Answer

Computing the eigenvalues of the system matrix numerically

Answer

Finding the gain margin from the Bode plot

Question 2

A second-order system with damping ratio ζ = 0.5 is classified as:

Accepted Answer

Underdamped

Answer

Overdamped

Answer

Critically damped

Answer

Undamped

Question 3

The gain margin of a control system is measured at the frequency where the open-loop phase angle equals:

Accepted Answer

−180°

Answer

0°

Answer

−90°

Answer

+180°

Question 4

In a Bode magnitude plot, a first-order lag factor (1 + jωT)^(−1) has a high-frequency asymptotic slope of:

Accepted Answer

−20 dB/decade

Answer

+20 dB/decade

Answer

−40 dB/decade

Answer

+40 dB/decade

Question 5

Root locus plots the trajectories of closed-loop poles as:

Accepted Answer

Open-loop gain K varies from 0 to ∞

Answer

Input frequency varies from 0 to ∞

Answer

Damping ratio ζ varies from 0 to 1

Answer

Time constant τ varies from 0 to ∞

Question 6

The phase margin of a stable feedback system is the additional phase lag that would cause:

Accepted Answer

The system to become marginally stable (oscillatory)

Answer

The gain to reach 0 dB

Answer

The steady-state error to become infinite

Answer

The bandwidth to decrease to zero

Question 7

Which of the following transfer functions represents a pure integrator?

Accepted Answer

K/s

Answer

K·s

Answer

K/(s + a)

Answer

K·s/(s + a)