1. A control system that does not require external feedback is called:
a) Closed-loop control system
b) Open-loop control system
c) Feedback control system
d) Feedforward control system
Answer:
b) Open-loop control system
Explanation:
An open-loop control system operates without the use of external feedback. It acts solely based on input signals.
2. In a control system, the 'transfer function' is used to relate:
a) Input and output in the time domain
b) Input and output in the frequency domain
c) The non-linearities of the system
d) The disturbances to the system stability
Answer:
b) Input and output in the frequency domain
Explanation:
The transfer function of a control system describes the relationship between the input and output in the frequency domain.
3. Which component in a control system is responsible for comparing the actual value to the desired value?
a) Actuator
b) Sensor
c) Comparator
d) Controller
Answer:
c) Comparator
Explanation:
The comparator in a control system compares the actual output value (feedback) with the desired output value (set point).
4. PID controller stands for:
a) Primary-Integral-Derivative controller
b) Proportional-Integral-Derivative controller
c) Proportional-Inductive-Derivative controller
d) Primary-Inductive-Derivative controller
Answer:
b) Proportional-Integral-Derivative controller
Explanation:
PID controller stands for Proportional-Integral-Derivative controller. It's a widely used control mechanism in control systems.
5. The purpose of 'feedforward control' in a control system is to:
a) Correct errors after they occur
b) Respond to set point changes
c) Compensate for known disturbances
d) Stabilize the system response
Answer:
c) Compensate for known disturbances
Explanation:
Feedforward control anticipates disturbances and compensates for them before they affect the system.
6. In control systems, 'overshoot' refers to:
a) The maximum output of the system
b) The time taken to reach the final value
c) The extent to which the response exceeds the desired value
d) The delay in the system response
Answer:
c) The extent to which the response exceeds the desired value
Explanation:
Overshoot is the amount by which a system's response exceeds its final steady-state value.
7. The 'steady-state error' in a control system is the:
a) Initial difference between the desired and actual output
b) Error when the system is first turned on
c) Difference between the desired and actual output at steady state
d) Total accumulated error over time
Answer:
c) Difference between the desired and actual output at steady state
Explanation:
Steady-state error is the difference between the system's desired and actual outputs once the system has settled and is in steady state.
8. The type of system which inherently maintains its output at a constant value in the presence of disturbances is:
a) An adaptive system
b) A robust system
c) A stable system
d) A self-regulating system
Answer:
d) A self-regulating system
Explanation:
A self-regulating system inherently maintains a constant output, adjusting to counteract disturbances.
9. Bode plot is a graphical representation of a system's:
a) Time response
b) Transfer function
c) Stability margins
d) Frequency response
Answer:
d) Frequency response
Explanation:
A Bode plot is a graphical representation of a system's frequency response, showing magnitude and phase versus frequency.
10. The Routh-Hurwitz criterion is used to determine:
a) System accuracy
b) System stability
c) System speed of response
d) System bandwidth
Answer:
b) System stability
Explanation:
The Routh-Hurwitz criterion is a mathematical test used to determine the stability of a control system.
11. Hysteresis in a control system is related to:
a) Time delay in response
b) Overshooting the set point
c) Different response for increasing and decreasing inputs
d) Variation in system parameters
Answer:
c) Different response for increasing and decreasing inputs
Explanation:
Hysteresis in control systems refers to the phenomenon where the system's response is different when the input increases compared to when it decreases.
12. A system is said to be 'marginally stable' if:
a) Its response oscillates with constant amplitude
b) Its response decays over time
c) Its response grows without bound
d) It responds instantly to inputs
Answer:
a) Its response oscillates with constant amplitude
Explanation:
A marginally stable system is one whose response oscillates indefinitely with a constant amplitude.
13. 'Root locus' is a technique used in control systems to:
a) Show the frequency response
b) Illustrate how the roots of a system change with system parameters
c) Display the time-domain response
d) Calculate the steady-state error
Answer:
b) Illustrate how the roots of a system change with system parameters
Explanation:
Root locus is a graphical method used to show how the roots of a system's characteristic equation change as a parameter (usually gain) varies.
14. The 'bandwidth' of a control system determines:
a) Its maximum operating frequency
b) The range of input frequencies it can handle
c) Its ability to reduce noise
d) The speed of its response
Answer:
b) The range of input frequencies it can handle
Explanation:
The bandwidth of a control system is the range of frequencies over which the system can respond effectively.
15. In a control system, 'dead time' refers to:
a) The time for the system to reach steady state
b) A delay between input and the start of the response
c) Time when the system is not functioning
d) The time to process a signal
Answer:
b) A delay between input and the start of the response
Explanation:
Dead time in a control system is the delay between the application of an input and the start of the system's response.
16. The primary function of a 'servo mechanism' in control systems is to:
a) Convert electrical signals to mechanical movement
b) Maintain system stability
c) Control large power loads
d) Respond to error signals
Answer:
d) Respond to error signals
Explanation:
A servo mechanism in control systems is a feedback control system used to correct performance based on error signals.
17. 'Gain margin' and 'phase margin' are measures of:
a) System accuracy
b) System stability
c) System speed
d) System bandwidth
Answer:
b) System stability
Explanation:
Gain margin and phase margin are measures used in control systems to assess the degree of stability of the system.
18. A system with a large damping ratio will have:
a) A fast response with oscillations
b) A slow response without oscillations
c) A fast response without oscillations
d) A slow response with oscillations
Answer:
b) A slow response without oscillations
Explanation:
A system with a large damping ratio tends to have a slower response with little to no oscillations.
19. 'Lead compensation' in control systems is used to:
a) Increase stability
b) Reduce response time
c) Increase overshoot
d) Decrease system gain
Answer:
b) Reduce response time
Explanation:
Lead compensation is used to improve the transient response of a system, generally reducing response time and improving stability.
20. The main advantage of state-space analysis in control systems is:
a) Simplicity in dealing with multiple-input multiple-output (MIMO) systems
b) Lower computational requirements
c) Ability to handle non-linear systems
d) Better visualization of system behavior
Answer:
a) Simplicity in dealing with multiple-input multiple-output (MIMO) systems
Explanation:
State-space analysis provides a framework for modeling and analyzing systems with multiple inputs and outputs, making it easier to handle complex MIMO systems.