How to Use Robotics System Toolbox in Simulink: Step-by-Step Guide

To use the Robotics System Toolbox in Simulink, add Robotics System Toolbox blocks from the Simulink Library Browser to your model. These blocks let you simulate robot kinematics, dynamics, and sensor data. Connect and configure these blocks to build robot algorithms and run simulations directly in Simulink.

Syntax

The Robotics System Toolbox in Simulink provides specialized blocks with this general usage pattern:

• Block Name: The specific robot or sensor function (e.g., Robot Arm, IMU Sensor).
• Input Ports: Connect signals such as joint angles, velocities, or sensor inputs.
• Output Ports: Provide robot states, sensor readings, or control signals.
• Parameters: Configure robot model properties like link lengths, masses, or sensor noise.

Example block syntax in Simulink model:

Robotics System Toolbox Block (e.g., Rigid Body Tree) → Inputs (joint angles) → Outputs (end-effector pose)

matlab

simulinkLibrary = 'robotics';
% Open Robotics System Toolbox library
open_system(simulinkLibrary);

Output

Simulink library 'robotics' opened showing Robotics System Toolbox blocks.

Example

This example shows how to simulate a simple 2-joint robot arm using Robotics System Toolbox blocks in Simulink.

• Use the Rigid Body Tree block to define the robot structure.
• Provide joint angle inputs using Signal Builder or Constant blocks.
• Use the Forward Kinematics block to compute the end-effector pose.
• Visualize the robot motion with the Robot Visualization block.

matlab

% Create a new Simulink model
modelName = 'robotics_example';
new_system(modelName);
open_system(modelName);

% Add Rigid Body Tree block
add_block('robotics/Robot Manipulators/Rigid Body Tree', [modelName '/Rigid Body Tree']);

% Add Constant blocks for joint angles
add_block('simulink/Sources/Constant', [modelName '/Joint1 Angle']);
set_param([modelName '/Joint1 Angle'], 'Value', 'pi/4');
add_block('simulink/Sources/Constant', [modelName '/Joint2 Angle']);
set_param([modelName '/Joint2 Angle'], 'Value', 'pi/6');

% Add Forward Kinematics block
add_block('robotics/Robot Manipulators/Forward Kinematics', [modelName '/Forward Kinematics']);

% Connect blocks
add_line(modelName, 'Joint1 Angle/1', 'Forward Kinematics/1');
add_line(modelName, 'Joint2 Angle/1', 'Forward Kinematics/2');
add_line(modelName, 'Rigid Body Tree/1', 'Forward Kinematics/3');

% Add Robot Visualization block
add_block('robotics/Robot Manipulators/Robot Visualization', [modelName '/Robot Visualization']);
add_line(modelName, 'Forward Kinematics/1', 'Robot Visualization/1');

% Save and run the model
save_system(modelName);
sim(modelName);

Output

Simulink model 'robotics_example' runs simulation showing robot arm pose updated based on joint angles.

Common Pitfalls

• Not loading the Robotics System Toolbox: Ensure the toolbox is installed and licensed before using its blocks.
• Incorrect block connections: Match input and output signal dimensions, especially joint vectors.
• Missing robot model: The Rigid Body Tree block requires a valid robot model object configured in MATLAB workspace.
• Ignoring simulation settings: Set appropriate solver and step size for accurate robot dynamics simulation.

matlab

% Wrong: Using joint angles as scalars instead of vectors
joint1 = pi/4;
joint2 = pi/6;
% Forward Kinematics expects a vector input
jointAngles = [joint1; joint2]; % Correct way

Quick Reference

Summary tips for using Robotics System Toolbox in Simulink:

• Open the Robotics System Toolbox library via open_system('robotics').
• Use Rigid Body Tree block to load robot models.
• Feed joint states as vectors to kinematics blocks.
• Visualize robot motion with Robot Visualization block.
• Configure simulation solver for real-time or fixed-step as needed.

Key Takeaways

Add Robotics System Toolbox blocks from the Simulink library to model robot components.

Configure robot models and provide joint inputs as vectors for kinematics calculations.

Use visualization blocks to see robot motion during simulation.

Ensure toolbox is installed and robot models are loaded in MATLAB workspace.

Set proper simulation solver settings for accurate robot behavior.