simulink-creator

Simulink Creator Skill

Overview

This skill generates complete, runnable MATLAB .m scripts that build Simulink models programmatically. Scripts must cover the full lifecycle: creating the model, adding and configuring blocks, connecting signals, arranging layout, and saving. If MATLAB is available, validate the script using MATLAB MCP or from terminal with matlab -batch "commands".

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Workflow

For every Simulink model request:

1. Understand the model — identify inputs, outputs, processing logic, and domain (control, signal processing, physical modeling, etc.)
2. Iterate with user — ask one clarifying question if the request is ambiguous (e.g., "What is the plant transfer function?" or "What signals should be logged?")
3. Identify required blocks — read references/simulink_blocks.md to confirm block names, descriptions, and doc links; read references/simulink_functions.md for API functions
4. Retrieve detailed docs — use web search with the doc links from the resource files to confirm library paths, port counts, and exact set_param key names
5. Generate a complete .m script — not snippets; a full runnable file following the structure below
6. Validate and iterate — if MATLAB available, verify the generated script via MATLAB MCP or from terminal with matlab -batch "commands", and iterates until the model simulates successfully.
7. Explain the code — briefly describe blocks used, closed-loop architecture, and how to run

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Code Quality Standards

• Define modelName as a variable at the top; never hardcode it in API calls
• Use [modelName '/BlockName'] string concatenation throughout
• Call close_system(modelName, 0) before new_system to prevent "already exists" errors
• Use %% section headers (MATLAB style)
• Define numeric parameters as workspace variables at the top for easy tuning
• All set_param values must be strings: '2.5' not 2.5
• Use unique, descriptive block names (e.g., Gain_Plant, Gain_Controller); add 'MakeNameUnique', 'on' option if needed
• Apply Simulink.BlockDiagram.arrangeSystem + manual Position for clean layout
• Use Subsystem blocks to encapsulate logical components
• End with disp(...) success message

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Script Template

%% =========================================================
%% [Model Name] — Simulink Model Creator Script
%% Description: [short description]
%% Generated for MATLAB/Simulink R20XXa or later
%% =========================================================

%% 1. Setup
modelName = 'MyModel';
close_system(modelName, 0);
new_system(modelName);
open_system(modelName);

%% 2. Parameters
% Define tunable numeric parameters here

%% 3. Add Blocks
% add_block('libraryPath/BlockType', [modelName '/InstanceName'])

%% 4. Set Block Parameters
% set_param([modelName '/BlockName'], 'ParameterKey', 'Value')

%% 5. Connect Blocks
% add_line(modelName, 'SrcBlock/OutPort#', 'DstBlock/InPort#')

%% 6. Arrange Layout
Simulink.BlockDiagram.arrangeSystem(modelName);
% Also set Position [left top right bottom] manually for clarity

%% 7. Save
save_system(modelName);
disp(['Model "' modelName '" created and saved successfully.']);

%% 8. Simulate
sim(modelName);
disp(['Model "' modelName '" has run successfully.']);

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API Reference

Always look up references/simulink_functions.md to confirm function signatures and retrieve doc links for detailed usage.

If details are not enough, perform a web search on the function.

Function	Purpose
new_system('modelName')	Create a new empty model
open_system('modelName')	Open a model or subsystem
close_system('modelName', 0)	Close without saving
save_system('modelName')	Save the model
load_system('modelName')	Load without opening the window
add_block('libraryPath/BlockType', 'modelName/BlockName')	Add a block to the model
set_param('modelName/BlockName', 'ParameterName', 'Value')	Set a parameter of a block
add_line('modelName', 'SourceBlock/Port', 'DestBlock/Port')	Add a line between two blocks
sim(modelName)	Run the simulation
get_param('modelName/BlockName', 'ParameterName')	Get a parameter of a block
Simulink.SubSystem.deleteContents('modelName/SubSystemBlock')	Delete all contents of a subsystem
Simulink.BlockDiagram.arrangeSystem('path')	Arrange the blocks in the model level
Simulink.findBlocksOfType(modelName,'Subsystem')	Find all blocks of a certain type

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Block Reference

Always look up references/simulink_blocks.md before using a block to confirm name, description, and the doc link.

Perform web search on that link to get the library path, port count, and exact set_param key names, if required.

If a block is not found in the resource file, use general Simulink knowledge and add:

% NOTE: Block reference not verified for 'BlockName' — confirm parameters before use.

Commonly Used Blocks

Name	Library Paths	Description
In1	simulink/Sources/In1	Provide an input port for a subsystem or model.
Out1	simulink/Sinks/Out1	Provide an output port for a subsystem or model.
Constant	simulink/Sources/Constant	Output the constant specified by the 'Constant value' parameter.
Step	simulink/Sources/Step	Output a step.
Sine Wave	simulink/Sources/Sine Wave	Output a sine wave.
Ground	simulink/Sources/Ground	Used to "ground" input signals. (Prevents warnings about unconnected input ports.) Outputs zero.
Terminator	simulink/Sinks/Terminator	Used to "terminate" output signals. (Prevents warnings about unconnected output ports.)
Scope	simulink/Sinks/Scope	Displays input signals with respect to simulation time
To Workspace	simulink/Sinks/To Workspace	Write input to specified timeseries, array, or structure in a workspace.
Sum	simulink/Math Operations/Sum	Add or subtract inputs.
Gain	simulink/Math Operations/Gain	Element-wise gain (y = K.u) or matrix gain (y = Ku or y = u*K).
Product	simulink/Math Operations/Product	Multiply or divide inputs.
Abs	simulink/Math Operations/Abs	Output the absolute value of the input signal.
Mux	simulink/Signal Routing/Mux	Combine scalar or vector signals of the same data type and complexity into a virtual vector. This block does not concatenate the signals.
Demux	simulink/Signal Routing/Demux	Split vector signals into scalars or smaller vectors.
Bus Creator	simulink/Signal Routing/Bus Creator	This block creates a bus from its inputs.
Bus Selector	simulink/Signal Routing/Bus Selector	Select nested buses and signals from the input bus.
Vector Concatenate	simulink/Math Operations/Vector Concatenate; simulink/Signal Routing/Vector Concatenate	Concatenate input signals of the same data type to create a contiguous output signal. Select vector or multidimensional array mode.
Switch	simulink/Signal Routing/Switch	Pass through input 1 when input 2 satisfies the selected criterion; otherwise, pass through input 3.
Subsystem	simulink/Ports & Subsystems/Subsystem	A subsystem block template containing an inport and outport block.
Integrator	simulink/Continuous/Integrator	Continuous-time integration of the input signal.
Transfer Fcn	simulink/Continuous/Transfer Fcn	The numerator coefficient can be a vector or matrix expression. The denominator coefficient must be a vector. The output width equals the number of rows in the numerator coefficient. You should specify the coefficients in descending order of powers of s.
PID Controller	simulink/Continuous/PID Controller	This block implements continuous- and discrete-time PID control algorithms and includes advanced features such as anti-windup, external reset, and signal tracking.
Unit Delay	simulink/Discrete/Unit Delay	Sample and hold with one sample period delay.
Memory	simulink/Discrete/Memory	Apply a one integration step delay. The output is the previous input value.
Delay	simulink/Discrete/Delay	Delay input signal by a specified number of samples.
Discrete-Time Integrator	simulink/Discrete/Discrete-Time Integrator	Discrete-time integration or accumulation of the input signal.
Discrete Transfer Fcn	simulink/Discrete/Discrete Transfer Fcn	Implement a z-transform transfer function. Specify the numerator and denominator coefficients in descending powers of z.
Saturation	simulink/Discontinuities/Saturation	Limit input signal to the upper and lower saturation values.
Logical Operator	simulink/Logic and Bit Operations/Logical Operator	Logical operators.
Relational Operator	simulink/Logic and Bit Operations/Relational Operator	Applies the selected relational operator to the inputs and outputs the result. The top (or left) input corresponds to the first operand.
Data Type Conversion	simulink/Signal Attributes/Data Type Conversion	Convert the input to the data type and scaling of the output.

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Code Patterns

Adding and Configuring Blocks

add_block('simulink/Sources/Sine Wave', [modelName '/SineInput']);
add_block('simulink/Math Operations/Gain', [modelName '/Gain1']);
add_block('simulink/Sinks/Scope', [modelName '/Scope']);

% Use exact key from block documentation
set_param([modelName '/Gain1'], 'Gain', '5');
set_param([modelName '/SineInput'], 'Frequency', '2*pi');

Connecting Blocks

% add_line(model, 'Source/OutPort#', 'Destination/InPort#')
add_line(modelName, 'SineInput/1', 'Gain1/1');
add_line(modelName, 'Gain1/1', 'Scope/1');

% Named signal (optional)
h = add_line(modelName, 'Gain1/1', 'Scope/1');
set_param(h, 'Name', 'gainedSignal');

Layout

% Auto-arrange top level
Simulink.BlockDiagram.arrangeSystem(modelName);

% Auto-arrange all nested subsystems
allSubsys = Simulink.findBlocksOfType(modelName, 'Subsystem');
for i = 1:numel(allSubsys)
    try; Simulink.BlockDiagram.arrangeSystem(allSubsys(i)); catch; end
end

% Manual positions [left, top, right, bottom]
set_param([modelName '/SineInput'], 'Position', [50,  100, 150, 130]);
set_param([modelName '/Gain1'],     'Position', [250, 100, 350, 130]);
set_param([modelName '/Scope'],     'Position', [450, 100, 500, 130]);

Simulation Parameters

set_param(modelName, 'StopTime',   '10');
set_param(modelName, 'Solver',     'ode45');
set_param(modelName, 'SolverType', 'Variable-step');
set_param(modelName, 'MaxStep',    '0.01');

Subsystems

add_block('simulink/Ports & Subsystems/Subsystem', [modelName '/Controller']);

% Clear default inport/outport
Simulink.SubSystem.deleteContents([modelName '/Controller']);

add_block('simulink/Ports & Subsystems/In1',  [modelName '/Controller/In1']);
add_block('simulink/Math Operations/Gain',    [modelName '/Controller/InnerGain']);
add_block('simulink/Ports & Subsystems/Out1', [modelName '/Controller/Out1']);

add_line([modelName '/Controller'], 'In1/1',       'InnerGain/1');
add_line([modelName '/Controller'], 'InnerGain/1', 'Out1/1');

Data Logging

add_block('simulink/Sinks/To Workspace', [mdl '/Logger']);
set_param([mdl '/Logger'], 'VariableName', 'simOut', 'SaveFormat', 'Array');

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Error Prevention

Mistake	Fix
Wrong set_param key	Look up the exact Block Parameter string from the block's official doc
Wrong library path	Look up the Libraries section in the block's official doc
Wrong port count in add_line	Check the Ports section in the block's official doc
Duplicate block names	Use descriptive names; add 'MakeNameUnique','on'
String vs. number params	set_param always takes strings: '2.5' not 2.5
"Model already exists" error	Always call close_system(modelName, 0) before new_system
Wrong connection direction	Always Source/outport → Destination/inport
Split signals	Call add_line twice from the same output port

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Interaction Guidelines

• If the request is ambiguous, ask one clarifying question (e.g., what is the plant / what are the I/O signals?)
• If the user provides a diagram, transfer function, or description, extract all info and generate without further questions
• Warn about optional toolbox requirements at the top of the script (e.g., Control System Toolbox, DSP System Toolbox)
• After delivering the model, offer one concrete extension (e.g., "I can add data logging to workspace or wrap the controller in a subsystem — just ask")