Control System Fundamentals: Master the Basics of Control Systems

Question 1

In a negative feedback control system, how is the error signal calculated?

Accepted Answer

The difference between the reference input and the controlled variable

Answer

The sum of the reference input and the controlled variable

Answer

The product of the reference input and the controlled variable

Answer

The quotient of the reference input divided by the controlled variable

Question 2

What is a potential drawback of incorporating feedback into a control system?

Accepted Answer

Increased complexity

Answer

Enhanced precision

Answer

Improved stability

Question 3

What is the fundamental purpose of a control system?

Accepted Answer

To automatically regulate a process or system.

Answer

To manually operate a process or system.

Answer

To monitor a process or system without any control.

Answer

To provide feedback on the performance of a process or system.

Question 4

How does a closed-loop control system differ from an open-loop control system?

Accepted Answer

A closed-loop system incorporates feedback, while an open-loop system does not.

Answer

An open-loop system incorporates feedback, while a closed-loop system does not.

Answer

A closed-loop system directly controls the output, while an open-loop system directly controls the input.

Answer

An open-loop system directly controls the output, while a closed-loop system directly controls the input.

Question 5

What is the purpose of a PID controller?

Accepted Answer

To adjust a system based on the error between the desired and actual output.

Answer

To provide a consistent output regardless of the input.

Answer

To amplify the input signal.

Answer

To integrate the error signal.

Question 6

What is the stability criterion for a closed-loop control system with transfer function G(s)?

Accepted Answer

All the poles of G(s) must have negative real parts.

Answer

All the poles of G(s) must have positive real parts.

Answer

All the zeros of G(s) must have negative real parts.

Answer

All the zeros of G(s) must have positive real parts.

Question 7

How does a step response differ from an impulse response?

Accepted Answer

A step response is caused by an abrupt input change, while an impulse response is caused by a brief pulse.

Answer

An impulse response is caused by an abrupt input change, while a step response is caused by a brief pulse.

Answer

A step response is caused by a continuous input change, while an impulse response is caused by a discrete input change.

Answer

An impulse response is caused by a continuous input change, while a step response is caused by a discrete input change.

Question 8

Which fundamental concept is central to control systems?

Accepted Answer

Feedback

Answer

Open-loop control

Answer

Binary logic

Answer

Analog transmission

Question 9

A block diagram in control systems represents:

Accepted Answer

Input-output relationships

Answer

The flow of energy

Answer

Physical components

Answer

Mathematical equations

Question 10

A closed-loop control system:

Accepted Answer

Utilizes feedback

Answer

Relies solely on open-loop control

Answer

Has one input and one output

Answer

Is inherently stable

Question 11

What is the primary function of negative feedback in a control system?

Accepted Answer

To reduce the error signal

Answer

To amplify the error signal

Answer

To eliminate the need for a sensor

Answer

To prevent the system from overloading

Question 12

A block diagram of a control system illustrates:

Accepted Answer

Signal flow through the system

Answer

System hardware components

Answer

System mathematical equations

Answer

System maintenance procedures

Question 13

The transfer function of a system with input x(t) and output y(t) is:

Accepted Answer

Y(t)/X(t)

Answer

X(t)/Y(t)

Answer

Y(t) - X(t)

Answer

X(t) + Y(t)

Question 14

What is a primary advantage of using a proportional-integral-derivative (PID) controller?

Accepted Answer

Elimination of steady-state error

Answer

Ease of implementation

Answer

High accuracy

Answer

Robustness to disturbances

Question 15

Which of these is NOT a characteristic of a control system?

Accepted Answer

Random output

Answer

Presence of a feedback loop

Answer

Goal-oriented behavior

Answer

Use of sensors

Question 16

In a block diagram, which symbol represents the point where multiple signals are added together?

Accepted Answer

Summing point

Answer

Subtracting point

Answer

Amplifier

Answer

Comparator

Question 17

For a proportional controller, what is the relationship between its gain (K) and its transfer function?

Accepted Answer

Transfer function = K

Answer

Transfer function = K/s

Answer

Transfer function = Ks

Answer

Transfer function = K/s^2

Question 18

How does a high gain in a control system typically affect the system's response time?

Accepted Answer

Decreases response time

Answer

Increases response time

Answer

Has no effect on response time

Answer

Reverses the direction of response

Question 19

In a domestic central heating system, which type of open-loop control is commonly employed?

Accepted Answer

Proportional control

Answer

Proportional-integral control

Answer

Proportional-derivative control

Answer

Proportional-integral-derivative control

Question 20

What is the primary purpose of a feedback control system?

Accepted Answer

To correct for disturbances and maintain the desired output

Answer

To generate a control signal independent of the output

Answer

To amplify the input signal

Answer

To store the output signal

Question 21

Which of the following parameters is used to assess the stability of a control system?

Accepted Answer

Phase margin

Answer

Overshoot

Answer

Settling time

Answer

Rise time

Question 22

In a closed-loop control system, how is the error signal calculated?

Accepted Answer

Reference signal minus output signal

Answer

Output signal minus reference signal

Answer

Reference signal plus output signal

Answer

Output signal divided by reference signal

Question 23

The primary purpose of a feedback control system is to:

Accepted Answer

Maintain a desired output variable

Answer

Amplify input signals

Answer

Generate oscillatory behaviour

Answer

Convert alternating current to direct current

Question 24

In a block diagram of a control system, the element representing the device or process being controlled is:

Accepted Answer

Plant

Answer

Reference input

Answer

Controller

Answer

Feedback sensor

Question 25

A characteristic of a type 1 control system is:

Accepted Answer

Finite steady-state error for step inputs

Answer

Zero steady-state error for both step and ramp inputs

Answer

Infinite gain margin

Answer

Unstable at low frequencies

Question 26

The Laplace transform of the function f(t) = e^(-2t) * sin(3t) is:

Accepted Answer

F(s) = (s + 2) / ((s + 2)^2 + 9)

Answer

F(s) = (s - 2) / ((s - 2)^2 + 9)

Answer

F(s) = (s + 3) / ((s + 2)^2 + 9)

Answer

F(s) = (s - 3) / ((s + 2)^2 + 9)

Question 27

A common method for designing a PID controller is:

Accepted Answer

Ziegler-Nichols tuning

Answer

Bode plot analysis

Answer

Root locus analysis

Answer

State-space analysis

Question 28

The role of a lead compensator in a control system is to:

Accepted Answer

Increase the phase margin

Answer

Reduce the gain margin

Answer

Introduce a time delay

Answer

Eliminate steady-state error

Question 29

The significance of the Nyquist stability criterion is that it:

Accepted Answer

Provides a graphical method to determine the stability of a control system

Answer

Is only applicable to systems with negative feedback

Answer

Can be used to calculate the phase margin of a system

Answer

Is useful for designing controllers with desired performance characteristics

Question 30

The primary distinction between an open-loop and a closed-loop control system is the:

Accepted Answer

Presence of feedback

Answer

Type of controller used

Answer

Number of inputs and outputs

Answer

Complexity of the system

Question 31

Why is stability analysis crucial in control systems?

Accepted Answer

To guarantee the system's intended operation, preventing undesirable oscillations or instability.

Answer

To calculate the system's precise response time.

Answer

To predict the system's efficiency.

Answer

To determine the system's lifespan.

Question 32

Which of the following is NOT a benefit of using control systems?

Accepted Answer

Reduced safety risks

Answer

Enhanced system performance

Answer

Increased efficiency

Answer

Improved accuracy and precision

Question 33

What is the key difference between analog and digital control systems?

Accepted Answer

Analog systems use continuous signals, while digital systems use discrete signals.

Answer

Digital systems are faster than analog systems.

Answer

Analog systems are more accurate than digital systems.

Answer

Digital systems are more reliable than analog systems.

Question 34

In a control system, the open-loop transfer function is G(s) = K/(s(s+2)). Determine the range of K values that ensure system stability.

Accepted Answer

0 < K < 2

Answer

K > 2

Answer

K < 0

Answer

0 < K < 4

Question 35

A control system has an open-loop transfer function of G(s) = 1/(s(s+3)). Using the Routh-Hurwitz criterion, is this system stable?

Accepted Answer

Yes, the system is stable.

Answer

No, the system is unstable.

Answer

More information is needed to determine stability.

Answer

The system is conditionally stable.

Question 36

What is the primary purpose of a feedback loop in a control system?

Accepted Answer

Reduce the error between the desired and actual output.

Answer

Stabilize the system.

Answer

Increase the system's gain.

Answer

Eliminate noise.

Question 37

Describe the step response of a first-order system.

Accepted Answer

Exponential decay

Answer

Square wave

Answer

Gaussian distribution

Answer

Sine wave

Question 38

Identify a characteristic of a well-tuned control system.

Accepted Answer

Minimal overshoot and settling time

Answer

Long time constant

Answer

Large dead zone

Answer

High gain

Question 39

Explain the fundamental difference between a closed-loop and an open-loop control system.

Accepted Answer

Closed-loop uses feedback; open-loop does not.

Answer

Closed-loop is more stable; open-loop is less stable.

Answer

Closed-loop is more accurate; open-loop is less accurate.

Question 40

In a control system, the primary function of feedback is to:

Accepted Answer

Reduce the error between the desired output and the actual output

Answer

Isolate the input from the output

Answer

Increase the gain of the system

Question 41

A system with a transfer function of G(s) = 1/(s+2) is classified as a:

Accepted Answer

First-order system

Answer

Second-order system

Answer

Fourth-order system

Answer

Third-order system

Question 42

A potential disadvantage of using a PID controller is:

Accepted Answer

Increased complexity in tuning

Answer

Reduced noise immunity

Answer

Lower stability margin

Answer

Increased sensitivity to disturbances

Question 43

A control system that uses a model of the plant to predict its behavior is referred to as:

Accepted Answer

Model predictive control

Answer

Fuzzy logic control

Answer

Adaptive control

Answer

Proportional-integral-derivative control