Referenced models in Simulink - Mini Project: Build & Apply

Referenced Models in Simulink

📖 Scenario: You are working on a car simulation project. The car has different parts like engine, transmission, and brakes. Each part is modeled separately in Simulink as a referenced model. You want to combine these parts into one main model to see how the whole car works together.

🎯 Goal: Build a main Simulink model that references three separate models: engine, transmission, and brakes. This will help you simulate the entire car system by combining these referenced models.

📋 What You'll Learn

Create three separate Simulink models named engine, transmission, and brakes with simple input-output blocks.

Create a main Simulink model named car_system that references the three models.

Connect the referenced models properly in the main model to simulate data flow.

Run the simulation and observe the combined output.

💡 Why This Matters

🌍 Real World

In real-world engineering, large systems are broken into smaller parts modeled separately. Referenced models help manage complexity and reuse parts.

💼 Career

Understanding referenced models is essential for system engineers and simulation specialists working with complex systems in automotive, aerospace, and robotics industries.

1

Create the engine model

Open Simulink and create a new model named engine. Add a Constant block with value 100 and connect it to an Out1 block. Save the model.

Simulink

% Create the engine model with a Constant block value 100 connected to Out1
% Your code here

Hint

Use new_system to create the model, add_block to add blocks, and add_line to connect them.

2

Create the transmission model

Create a new model named transmission. Add a Gain block with gain 2 and connect its input to an In1 block and output to an Out1 block. Save the model.

Simulink

% Create transmission model with In1 connected to Gain block (gain=2) connected to Out1
% Your code here

Hint

Remember to add In1 and Out1 blocks and connect them through the Gain block.

3

Create the main car_system model with referenced models

Create a new model named car_system. Add three Model blocks referencing engine, transmission, and brakes models. Connect the output of engine to the input of transmission. Save the model.

Simulink

% Create car_system model with referenced engine, transmission, and brakes models
% Connect engine output to transmission input
% Your code here

Hint

Use Model blocks to reference other models. Connect the output port 1 of engine_ref to input port 1 of transmission_ref.

4

Run the simulation and display output

Load the car_system model and run the simulation. Use simOut to store the simulation output. Print the simulation output for the transmission_ref block.

Simulink

% Load car_system model and run simulation
% Print the output of transmission_ref
% Your code here

Hint

Use sim to run the model and disp to print the output.

Practice

1. What is the main purpose of using Referenced models in Simulink?

easy

A. To reuse parts of models and simplify large projects

B. To create new Simulink blocks from scratch

C. To export models as images

D. To run simulations faster by skipping blocks

Solution

1. Step 1: Understand the role of referenced models

   Referenced models allow you to include one model inside another, making reuse possible.

2. Step 2: Connect reuse to project management

   By reusing parts, you keep big projects organized and easier to update.

3. Final Answer:

   To reuse parts of models and simplify large projects -> Option A

4. Quick Check:

   Referenced models = reuse and simplify [OK]

Hint: Think reuse and organization for big Simulink projects [OK]

Common Mistakes:

• Confusing referenced models with creating new blocks
• Thinking referenced models speed up simulation by skipping
• Assuming referenced models export images

2. Which of the following is the correct way to add a referenced model in Simulink?

easy

A. Drag a Model block and set its Model name parameter to the referenced model file

B. Use the MATLAB command add_block('model') without parameters

C. Copy and paste the entire model into the current model

D. Create a new subsystem and name it after the referenced model

Solution

1. Step 1: Recall how to include referenced models

   Simulink uses Model blocks to include referenced models by specifying the model file name.

2. Step 2: Check options for correctness

   Drag a Model block and set its Model name parameter to the referenced model file correctly describes dragging a Model block and setting its Model name parameter.

3. Final Answer:

   Drag a Model block and set its Model name parameter to the referenced model file -> Option A

4. Quick Check:

   Model block + Model name = referenced model [OK]

Hint: Use Model block and set model name to reference [OK]

Common Mistakes:

• Using add_block without parameters causes errors
• Copy-pasting duplicates instead of referencing
• Naming subsystems does not create references

3. Given a Simulink model with a Model block referencing subsystemA, what happens if subsystemA is updated externally and saved before simulation?

medium

A. Simulation fails with an error about missing blocks

B. The main model ignores changes and uses the old version

C. The main model uses the updated subsystemA during simulation

D. The referenced model is duplicated inside the main model automatically

Solution

1. Step 1: Understand referenced model behavior on update

   Referenced models reflect changes made externally when saved before simulation.

2. Step 2: Analyze simulation effect

   The main model uses the latest saved version of the referenced model during simulation.

3. Final Answer:

   The main model uses the updated subsystemA during simulation -> Option C

4. Quick Check:

   Referenced models update = main model uses latest [OK]

Hint: Referenced models always use saved latest version at simulation [OK]

Common Mistakes:

• Assuming main model caches old referenced model version
• Thinking simulation fails if referenced model changes
• Believing referenced models duplicate automatically

4. You added a referenced model block but get an error: Model file not found. What is the most likely cause?

medium

A. The simulation time is set to zero

B. The referenced model file path is incorrect or missing

C. The referenced model has no input ports

D. The main model is not saved

Solution

1. Step 1: Identify cause of 'Model file not found'

   This error usually means Simulink cannot locate the referenced model file due to wrong or missing path.

2. Step 2: Check other options for relevance

   Saving main model, input ports, or simulation time do not cause this error.

3. Final Answer:

   The referenced model file path is incorrect or missing -> Option B

4. Quick Check:

   File not found = wrong or missing path [OK]

Hint: Check referenced model file path if 'not found' error appears [OK]

Common Mistakes:

• Ignoring file path issues
• Blaming simulation time or ports incorrectly
• Not saving main model but error is unrelated

5. You want to create a large Simulink project with multiple teams working on different parts. How do referenced models help in this scenario?

hard

A. Referenced models run simulations independently without integration

B. Referenced models automatically merge all team changes into one file

C. Referenced models prevent any changes once included in the main model

D. Each team works on separate referenced models that are included in the main model, easing collaboration

Solution

1. Step 1: Understand team collaboration with referenced models

   Referenced models allow teams to work on separate model files independently.

2. Step 2: Connect referenced models to main model integration

   The main model includes these referenced models, making integration easier and organized.

3. Final Answer:

   Each team works on separate referenced models that are included in the main model, easing collaboration -> Option D

4. Quick Check:

   Referenced models = team collaboration and modular design [OK]

Hint: Use referenced models for modular teamwork in big projects [OK]

Common Mistakes:

• Thinking referenced models merge files automatically
• Assuming referenced models lock changes
• Believing referenced models simulate independently without integration