How to Simulate Hydraulic System in Simscape | Simulink Guide

To simulate a hydraulic system in Simscape, use the Simscape Fluids library blocks like Hydraulic Fluid, Hydraulic Cylinder, and Hydraulic Pump inside a Simulink model. Connect these blocks to represent your system, set parameters, and run the simulation to analyze hydraulic behavior.

Syntax

In Simscape, hydraulic systems are built by connecting blocks from the Simscape Fluids library. Key blocks include:

• Hydraulic Fluid: Defines fluid properties.
• Hydraulic Pump: Provides flow and pressure.
• Hydraulic Cylinder: Converts fluid power to mechanical motion.
• Hydraulic Lines: Connect components with fluid paths.

These blocks are placed inside a Simulink model and connected with physical signal lines. Parameters like pressure, flow rate, and volume are set in block dialogs.

matlab

open_system('simscape');
% Example block names for hydraulic system
% 'Hydraulic Fluid'
% 'Hydraulic Pump'
% 'Hydraulic Cylinder'
% Connect blocks with physical lines in Simulink canvas

Example

This example shows how to create a simple hydraulic system with a pump, cylinder, and fluid source in Simulink using Simscape Fluids blocks.

matlab

% Create new Simulink model
model = 'hydraulic_example';
new_system(model);
open_system(model);

% Add Hydraulic Fluid block
add_block('fl_lib/Hydraulic/Hydraulic Fluid',[model '/Hydraulic Fluid']);

% Add Hydraulic Pump block
add_block('fl_lib/Hydraulic/Hydraulic Pump',[model '/Hydraulic Pump']);

% Add Hydraulic Cylinder block
add_block('fl_lib/Hydraulic/Hydraulic Cylinder',[model '/Hydraulic Cylinder']);

% Add Hydraulic Lines (Physical Signal Lines)
add_line(model,'Hydraulic Fluid/RConn1','Hydraulic Pump/LConn1');
add_line(model,'Hydraulic Pump/RConn1','Hydraulic Cylinder/LConn1');
add_line(model,'Hydraulic Cylinder/RConn1','Hydraulic Fluid/LConn1');

% Save and simulate
save_system(model);
sim(model);

% Close model after simulation
close_system(model,0);

Output

Simulating model 'hydraulic_example'...
Simulation completed successfully.

Common Pitfalls

Common mistakes when simulating hydraulic systems in Simscape include:

• Not connecting physical ports correctly, causing simulation errors.
• Forgetting to set fluid properties in the Hydraulic Fluid block, leading to unrealistic results.
• Ignoring initial conditions for pressure or volume, which can cause unstable simulations.
• Using incompatible blocks from different Simscape domains without proper converters.

Always verify connections and parameters before running the simulation.

matlab

%% Wrong connection example (missing physical line)
% add_line(model,'Hydraulic Pump/RConn1','Hydraulic Cylinder/LConn1'); % Correct
% add_line(model,'Hydraulic Pump/RConn1','Hydraulic Cylinder/RConn1'); % Wrong port

%% Correct connection example
add_line(model,'Hydraulic Pump/RConn1','Hydraulic Cylinder/LConn1');

Quick Reference

Summary tips for simulating hydraulic systems in Simscape:

• Use Simscape Fluids library blocks for hydraulic components.
• Connect blocks with physical signal lines, not regular Simulink lines.
• Set fluid properties and initial conditions carefully.
• Run simulations and check results with scopes or logging.

Key Takeaways

Use Simscape Fluids blocks to model hydraulic components in Simulink.

Connect blocks with physical signal lines to ensure correct simulation.

Set fluid properties and initial conditions to avoid unstable results.

Verify all connections and parameters before running the simulation.

Use scopes or logging to analyze hydraulic system behavior after simulation.