Load disturbance response in Simulink - Step-by-Step Execution

Concept Flow - Load disturbance response

Start Simulation

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Apply Load Disturbance

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System Response

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Measure Output Change

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Analyze Recovery Time & Stability

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End Simulation

The flow shows how a load disturbance is applied to a system, the system responds, and we measure how the output changes and recovers.

Execution Sample

Simulink

1. Set up Simulink model with plant and controller
2. Add load disturbance input block
3. Run simulation
4. Observe output response plot
5. Analyze disturbance effect

This code sets up and runs a Simulink simulation to observe how the system output responds to a load disturbance.

Execution Table

Step	Action	Input Disturbance	System Output	Observation
1	Start simulation	0	Steady at setpoint	System stable before disturbance
2	Apply load disturbance	Sudden step increase	Output dips below setpoint	Disturbance causes output drop
3	Controller reacts	Disturbance present	Output starts rising	Controller tries to correct error
4	Output recovers	Disturbance constant	Output approaches setpoint	System stabilizing
5	Disturbance removed	Back to 0	Output steady at setpoint	System returns to normal
6	End simulation	0	Steady at setpoint	Simulation complete

💡 Simulation ends after output stabilizes post disturbance

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
Input Disturbance	0	Step increase	Step increase	Step increase	0	0
System Output	Setpoint	Drops below setpoint	Rising	Near setpoint	Setpoint	Setpoint

Key Moments - 2 Insights

Why does the system output drop immediately after the disturbance is applied?

Because the disturbance is a sudden load increase, it causes the output to deviate from the setpoint before the controller can react, as shown in execution_table step 2.

How does the controller help the system recover after disturbance?

The controller detects the error caused by the disturbance and adjusts the control input to bring the output back to the setpoint, as seen in execution_table step 3 and 4.

Visual Quiz - 3 Questions

Look at the execution table, what happens to the system output at step 2?

A Output rises above setpoint

B Output stays steady

C Output drops below setpoint

D Output oscillates wildly

💡 Hint

Refer to execution_table row with Step 2 under System Output column

At which step does the controller start reacting to the disturbance?

A Step 3

B Step 2

C Step 1

D Step 5

💡 Hint

Check execution_table rows for when System Output starts rising after disturbance

If the disturbance was never removed, how would the final system output most likely behave?

A Return to setpoint

B Stay near but not at setpoint

C Remain below setpoint

D Increase above setpoint

💡 Hint

Consider variable_tracker showing output approaching setpoint but disturbance still present

Concept Snapshot

Load disturbance response in Simulink:
- Apply sudden load change to system input
- Observe output deviation from setpoint
- Controller acts to correct error
- Output recovers to setpoint over time
- Analyze recovery time and stability
- Useful for testing system robustness

Full Transcript

This visual execution traces how a load disturbance affects a system in Simulink. The simulation starts with the system stable at setpoint. When a sudden load disturbance is applied, the output drops below the setpoint. The controller detects this error and reacts by adjusting control inputs. Over time, the output recovers and approaches the setpoint again. Finally, when the disturbance is removed, the system output stabilizes back at the setpoint. The variable tracker shows how the disturbance input and system output change step-by-step. Key moments clarify why output drops immediately and how the controller helps recovery. The quiz tests understanding of output behavior and controller action during disturbance response.