Load disturbance response in Simulink - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Simulink Load Disturbance Step Response Output

Given a Simulink model simulating a load disturbance on a control system, what is the expected shape of the output response plot after a step disturbance is applied?

Simulink

Step disturbance applied at t=5s; system output recorded from 0 to 20s.

A The output shows a sudden drop at t=5s followed by a gradual return to steady state.

B The output remains constant with no visible change after t=5s.

C The output shows a continuous oscillation starting at t=0s with no disturbance effect.

D The output shows a sudden increase at t=0s and then stabilizes immediately.

💡 Hint

Think about how a load disturbance typically affects system output in control systems.

A load disturbance usually causes a sudden change in output (like a drop or rise) at the disturbance time, followed by the system's response to return to steady state.

❓ data_output

intermediate

Data Output from Load Disturbance Simulation

After running a Simulink load disturbance simulation, which data output array correctly represents the system output values at times [4, 5, 6] seconds?

Simulink

Output data array: [1.0, 0.5, 0.8] at times [4, 5, 6] seconds respectively.

A [0.8, 0.5, 1.0]

B [0.5, 1.0, 0.8]

C [1.0, 1.0, 1.0]

D [1.0, 0.5, 0.8]

💡 Hint

Check the output values at the exact times given.

The output at t=4s is before disturbance so steady at 1.0; at t=5s disturbance causes drop to 0.5; at t=6s system starts recovering to 0.8.

❓ visualization

advanced

Identify the Correct Load Disturbance Response Plot

Which plot correctly represents a typical load disturbance response in a Simulink control system?

A Plot with a flat line throughout the simulation.

B Plot with a sharp dip at disturbance time followed by smooth recovery.

C Plot with increasing oscillations starting at disturbance time.

D Plot with a sudden jump at start and no further changes.

💡 Hint

Load disturbances cause sudden output changes then recovery, not constant or oscillatory behavior.

A load disturbance typically causes a sudden change (dip or spike) in output, then the system tries to recover smoothly to steady state.

🧠 Conceptual

advanced

Effect of Load Disturbance on System Stability

What is the primary effect of a load disturbance on the stability of a closed-loop control system in Simulink?

A It temporarily shifts the output but the system returns to steady state if stable.

B It causes the system to become unstable and output diverges indefinitely.

C It permanently changes the system parameters causing new steady state.

D It has no effect on output or stability.

💡 Hint

Consider how stable systems respond to disturbances.

A stable closed-loop system will respond to load disturbances with a temporary output change but will return to steady state.

🔧 Debug

expert

Debugging Unexpected Load Disturbance Response

A Simulink model shows no output change after applying a load disturbance step at t=5s. Which is the most likely cause?

A The simulation stop time is set before t=5s.

B The output scope is not set to record data.

C The disturbance input is not connected properly to the system block.

D The step disturbance magnitude is zero.

💡 Hint

Check signal connections first when disturbance has no effect.

If the disturbance input is not connected, the system never receives the disturbance, so output stays unchanged.