FEEDBACK CONTROL SYSTEMS ACTUAL
TEST QUESTIONS AND SOLUTIONS
COMPREHENSIVE REVIEW PACKAGE
●● What is a feedback control system?
Answer: A system of sensors, control algorithms, and actuators designed
to control the output of a dynamic system to follow a commanded value.
●● What is an example of a feedback control system in a hot water
geyser?
Answer: Sensors: Thermometer; Actuator: Heating element;
Commanded value: 60 degrees Celsius.
●● What does the control algorithm do in a geyser feedback system?
Answer: It switches on the heater if the temperature is below 55 degrees
Celsius and switches it off if above 65 degrees Celsius.
●● What is the dynamic process in the geyser example?
Answer: The output is the water temperature.
●● What are the components of a feedback controller?
Answer: The plant, sensors, controller, and input filter.
,●● What is the 'plant' in a control system?
Answer: The dynamic process that is controlled to follow a desired
reference signal.
●● What is the role of sensors in a feedback control system?
Answer: To measure the output of the plant and provide data for the
control algorithm.
●● What is an error signal?
Answer: The difference between the reference signal and the output of
the plant, indicating how far off the output is.
●● What is the goal of the controller in a feedback system?
Answer: To drive the error signal to zero, making the output match the
desired reference signal.
●● What is the purpose of an input filter in a control system?
Answer: To modify the shape of the reference signal to improve the
system's response.
●● What is disturbance rejection in feedback control?
Answer: Minimizing the influence of disturbances on the output signal.
,●● What is sensor noise?
Answer: Measurement errors in sensors that can affect the accuracy of
the output signal.
●● What is the difference between open loop and closed loop control?
Answer: Open loop control does not use output measurements for
control actions, while closed loop control does.
●● What are the goals of feedback control?
Answer: Stability, command tracking, disturbance rejection, and
robustness.
●● Define stability in the context of control systems.
Answer: A system is stable if its dynamic response eventually reaches
equilibrium.
●● What happens in an unstable system?
Answer: The dynamic response grows monotonically or oscillates with
increasing amplitude, potentially leading to failure.
●● What is command tracking?
Answer: The ability of a control system to ensure the output follows a
desired reference signal.
, ●● What is a dynamic process in control systems?
Answer: A process whose output is influenced by control signals and
disturbances.
●● What is the role of the actuator in a control system?
Answer: To influence the process based on the control signal from the
controller.
●● What is the significance of robustness in control systems?
Answer: The ability to achieve control goals even with inaccuracies in
the model or changing dynamics.
●● How does a controller respond to sensor noise?
Answer: It must be fast enough to respond to actual changes but slow
enough to avoid reacting to noise.
●● What is an example of a disturbance in a drone control system?
Answer: A gust of wind affecting the drone's altitude.
●● What is the commanded value in a drone feedback control system?
Answer: The GPS position that the drone is supposed to maintain.
●● What sensors are typically used in a drone feedback control system?
TEST QUESTIONS AND SOLUTIONS
COMPREHENSIVE REVIEW PACKAGE
●● What is a feedback control system?
Answer: A system of sensors, control algorithms, and actuators designed
to control the output of a dynamic system to follow a commanded value.
●● What is an example of a feedback control system in a hot water
geyser?
Answer: Sensors: Thermometer; Actuator: Heating element;
Commanded value: 60 degrees Celsius.
●● What does the control algorithm do in a geyser feedback system?
Answer: It switches on the heater if the temperature is below 55 degrees
Celsius and switches it off if above 65 degrees Celsius.
●● What is the dynamic process in the geyser example?
Answer: The output is the water temperature.
●● What are the components of a feedback controller?
Answer: The plant, sensors, controller, and input filter.
,●● What is the 'plant' in a control system?
Answer: The dynamic process that is controlled to follow a desired
reference signal.
●● What is the role of sensors in a feedback control system?
Answer: To measure the output of the plant and provide data for the
control algorithm.
●● What is an error signal?
Answer: The difference between the reference signal and the output of
the plant, indicating how far off the output is.
●● What is the goal of the controller in a feedback system?
Answer: To drive the error signal to zero, making the output match the
desired reference signal.
●● What is the purpose of an input filter in a control system?
Answer: To modify the shape of the reference signal to improve the
system's response.
●● What is disturbance rejection in feedback control?
Answer: Minimizing the influence of disturbances on the output signal.
,●● What is sensor noise?
Answer: Measurement errors in sensors that can affect the accuracy of
the output signal.
●● What is the difference between open loop and closed loop control?
Answer: Open loop control does not use output measurements for
control actions, while closed loop control does.
●● What are the goals of feedback control?
Answer: Stability, command tracking, disturbance rejection, and
robustness.
●● Define stability in the context of control systems.
Answer: A system is stable if its dynamic response eventually reaches
equilibrium.
●● What happens in an unstable system?
Answer: The dynamic response grows monotonically or oscillates with
increasing amplitude, potentially leading to failure.
●● What is command tracking?
Answer: The ability of a control system to ensure the output follows a
desired reference signal.
, ●● What is a dynamic process in control systems?
Answer: A process whose output is influenced by control signals and
disturbances.
●● What is the role of the actuator in a control system?
Answer: To influence the process based on the control signal from the
controller.
●● What is the significance of robustness in control systems?
Answer: The ability to achieve control goals even with inaccuracies in
the model or changing dynamics.
●● How does a controller respond to sensor noise?
Answer: It must be fast enough to respond to actual changes but slow
enough to avoid reacting to noise.
●● What is an example of a disturbance in a drone control system?
Answer: A gust of wind affecting the drone's altitude.
●● What is the commanded value in a drone feedback control system?
Answer: The GPS position that the drone is supposed to maintain.
●● What sensors are typically used in a drone feedback control system?
