Robust Control Techniques: Master Stability and Performance in Uncertain Systems

Question 1

Which of the following is NOT a primary objective of robust control?

Accepted Answer

Completely eliminate all uncertainties and disturbances

Answer

Ensure system stability despite uncertainties

Answer

Enhance system performance in the presence of disturbances

Answer

Make the system insensitive to plant parameter variations

Question 2

Which of the following is a key characteristic of robust control systems?

Accepted Answer

Ensure stability and performance in the presence of uncertainties and disturbances

Answer

Guarantee high performance regardless of operating conditions

Answer

Minimize response time to changes in the system

Answer

Eliminate the impact of external noise and disturbances

Question 3

Which technique is commonly employed for the design of robust control systems?

Accepted Answer

H-infinity control

Answer

PID control

Answer

Sliding mode control

Answer

Root locus analysis

Question 4

Which trade-off is commonly encountered in robust control design?

Accepted Answer

Robustness versus performance

Answer

Stability versus control effort

Answer

Accuracy versus computational complexity

Answer

Speed versus precision

Question 5

For a system with a step disturbance, which robust controller is most likely to minimize the overshoot in the system response?

Accepted Answer

Sliding mode controller

Answer

H-infinity controller

Answer

LQR controller

Answer

PID controller

Question 6

For a system with a time delay, which robust control technique is most appropriate to address this issue?

Accepted Answer

Time-delay control

Answer

Gain scheduling

Answer

Adaptive control

Answer

Pole placement

Question 7

In robust control design, the main goal is to:

Accepted Answer

Minimize the effects of uncertainties on system performance.

Answer

Increase the system's operating range.

Answer

Completely eliminate all sources of uncertainty.

Answer

Improve the system's speed of response.

Question 8

What is a primary goal of robust control design?

Accepted Answer

To make control systems insensitive to changes in plant parameters and disturbances.

Answer

To create control systems that need a precise and complete mathematical model of the plant.

Answer

To restrict robust control design to linear systems only.

Answer

To make robust control design unnecessary in well-controlled and predictable environments.

Question 9

Which of the following is NOT a type of robust control technique covered in this unit?

Accepted Answer

Model predictive control

Answer

H-infinity control

Answer

Gain scheduling

Answer

Adaptive control

Question 10

When designing an H-infinity controller, what is the primary objective?

Accepted Answer

Minimize the H-infinity norm of the closed-loop transfer function

Answer

Maximize the system's stability

Answer

Ensure the system's robustness to disturbances

Answer

Optimize the system's transient response

Question 11

Which of the following is a common approach used in adaptive control?

Accepted Answer

Model reference adaptive control (MRAC)

Answer

Pole placement

Answer

Linear quadratic regulator (LQR)

Answer

Kalman filter

Question 12

What is the central challenge in designing robust control systems?

Accepted Answer

Accounting for uncertainties and disturbances in the system

Answer

Finding the optimal controller gains for all operating conditions

Answer

Ensuring the stability of the closed-loop system

Answer

Implementing the controller in real-time

Question 13

Which of the following key performance metrics is used to evaluate the robustness of a control system?

Accepted Answer

Sensitivity function

Answer

Root locus

Answer

Nyquist stability criterion

Answer

Bode plot

Question 14

Consider a control system with uncertain parameters. Which robust control technique is best suited to guarantee stability and performance?

Accepted Answer

H-infinity control

Answer

Gain scheduling

Answer

Adaptive control

Answer

Pole placement

Question 15

What is the fundamental distinction between H-infinity and LQR control?

Accepted Answer

H-infinity control considers uncertainty, while LQR does not.

Answer

LQR control considers uncertainty, while H-infinity does not.

Answer

H-infinity control is optimal in the frequency domain, while LQR is optimal in the time domain.

Answer

LQR control is optimal in the frequency domain, while H-infinity is optimal in the time domain.

Question 16

What is the role of the reference model in model reference adaptive control?

Accepted Answer

It specifies the desired system behavior.

Answer

It is used to estimate the system parameters.

Answer

It generates the control signal.

Answer

It ensures the stability of the closed-loop system.

Question 17

Which primary objective of robust control is to ensure:

Accepted Answer

System stability despite uncertainties and disturbances

Answer

Minimization of system performance degradation due to disturbances

Answer

Optimization of system response time

Answer

Reduction of system overshoot

Question 18

In the H-infinity control approach, the optimization problem aims to minimize which metric:

Accepted Answer

The peak value of the closed-loop transfer function

Answer

The integrated squared error of the system output

Answer

The variance of the system output

Answer

The rise time of the system

Question 19

Which control method involves online adjustment of control parameters based on measured system response:

Accepted Answer

Adaptive control

Answer

Gain scheduling

Answer

Conventional PID control

Answer

Model predictive control

Question 20

In gain scheduling, the adjustment of control parameters primarily depends on:

Accepted Answer

The operating condition or point of the system

Answer

The time of day

Answer

The external disturbances acting on the system

Answer

The desired system response

Question 21

The term 'stability margin' in robust control refers to the measure of:

Accepted Answer

The system's ability to withstand uncertainties

Answer

The system's response speed

Answer

The accuracy of the system's output

Answer

The efficiency of the control algorithm

Question 22

For designing a robust controller for a system with unknown parameters, which technique is most suitable:

Accepted Answer

Adaptive control

Answer

Pole placement

Answer

Root locus analysis

Answer

State space feedback

Question 23

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

Accepted Answer

Reduce the system's sensitivity to uncertainties

Answer

Enhance the frequency range of the system

Answer

Improve the system's ability to follow references

Answer

Minimize overshoot in the system's response

Question 24

Robust control techniques are particularly useful for applications where:

Accepted Answer

Uncertainties or disturbances are present in the system

Answer

High performance requirements are critical

Answer

System behavior is precisely known

Answer

Time delays are insignificant

Question 25

H-infinity control is a robust control technique that focuses on:

Accepted Answer

Minimizing the worst-case system output

Answer

Maximizing the system stability margin

Answer

Optimizing the controller gains

Answer

Canceling external disturbances

Question 26

Gain scheduling involves:

Accepted Answer

Adjusting controller parameters based on system operating conditions

Answer

Designing a single controller for multiple operating points

Answer

Adapting the controller online

Answer

Using robust controllers for all possible uncertainties

Question 27

In H-infinity control, the optimization objective is to minimize:

Accepted Answer

|G(s)W(s)|

Answer

|G(s) - W(s)|

Answer

|C(s) - T(s)|

Answer

|S(s) - R(s)|

Question 28

A common method for designing gain-scheduled controllers is:

Accepted Answer

Linear Quadratic Regulator (LQR)

Answer

Pole placement

Answer

H-infinity synthesis

Answer

Model predictive control

Question 29

In adaptive control, the controller parameters:

Accepted Answer

Are adjusted online based on system data

Answer

Remain fixed and predetermined

Answer

Are optimized using numerical methods

Answer

Are manually tuned by an expert

Question 30

What is the fundamental objective of H-infinity control?

Accepted Answer

Minimizing the sensitivity function of the closed-loop system to external disturbances

Answer

Maximizing the stability margin of the closed-loop system

Answer

Optimizing the bandwidth of the closed-loop system

Answer

Reducing a cost function related to system performance

Question 31

Which of the following methods is commonly used to design gain-scheduled controllers?

Accepted Answer

Linear interpolation between multiple controllers

Answer

Nonlinear optimization techniques

Answer

Frequency response analysis

Answer

Pole placement techniques

Question 32

Adaptive control stands out from traditional control methods primarily due to its:

Accepted Answer

Ability to handle unknown or time-varying system parameters

Answer

Elimination of the need for accurate system modeling

Answer

Faster response times

Answer

Lower implementation costs

Question 33

Consider a control system with transfer function G(s). When a controller C(s) is added, which of the following represents the closed-loop transfer function?

Accepted Answer

G(s) / (1 + G(s) * C(s))

Answer

C(s) / (1 + G(s) * C(s))

Answer

G(s) + C(s)

Answer

G(s) * C(s)

Question 34

In H-infinity control, what purpose does a weighting function serve?

Accepted Answer

Specifying desired closed-loop performance characteristics

Answer

Reducing system sensitivity to external disturbances

Answer

Enhancing system stability

Answer

Optimizing controller parameters

Question 35

Which of the following is a benefit of using robust control techniques?

Accepted Answer

Reduced sensitivity to parameter variations

Answer

Reduced robustness to disturbances

Answer

Increased sensitivity to noise

Answer

Reduced performance

Question 36

Which of the following is NOT a common robust control technique?

Accepted Answer

Fuzzy logic control

Answer

H-infinity control

Answer

Adaptive control

Answer

Gain scheduling

Question 37

Which of the following is a key advantage of adaptive control?

Accepted Answer

Ability to handle time-varying parameters

Answer

Guaranteed stability

Answer

Ease of implementation

Question 38

In H-infinity control, the H-infinity norm represents:

Accepted Answer

The worst-case gain from disturbances to controlled outputs

Answer

The stability margin of the system

Answer

The maximum amplitude of the system's response

Question 39

Which of the following is a potential limitation of robust control techniques?

Accepted Answer

Increased computational complexity

Answer

Inability to handle nonlinear systems

Answer

Reduced accuracy

Answer

Ease of tuning

Question 40

What is the key distinction between H-infinity control and traditional control methods?

Accepted Answer

H-infinity control explicitly considers uncertainty and disturbances in the design process

Answer

H-infinity control is only applicable to linear systems

Answer

H-infinity control is less computationally efficient