JSBSim provides an S-Function to interface your flight dynamics model with MATLAB and Simulink.
Below are the instructions to build the S-Function from JSBSim Windows installer.
Download the JSBSim source from JSBSim release section.
Alternatively, you can clone the source using git:
> git clone https://github.com/JSBSim-Team/jsbsim/tree/v1.2.1Build the source following the instructions in the JSBSim Manual. Since we are using MacOS, we must build with CMake.
In order to work with the JSBSim MATLAB S-Function block, we must move some
files into the build/ directory. From the command line, make sure your
current directory is the root of the jsbsim/ source code.
> pwd
/path/to/jsbsimThen, we must copy some files into the build. These are necessary for the S-Function to operate.
> cp -r aircraft build/src/aircraft
> cp -r engine build/src/engine
> cp -r scripts build/src/scriptsIn jsbsim/matlab open JSBSimSimulinkCompiler.m and entire that the line
below For MacOS: is the only one that is not commented out. In the MATLAB
command line, run the script. Then, from the root of the source code,
copy the following files into the build source:
> cp matlab/JSBSim_SFunction.mexmaci64 build/src/JSBSim_SFunction.mexmaci64
> cp matlab/ex737cruise.slx build/src/ex737cruise.slx
> cp matlab/TestJSBSim.m build/src/TestJSBSim.m
> cp matlab/clearSF.m build/src/clearSF.mYou can now follow the test instructions below in order to ensure it is in working condition.
Once you have the S-Function compiled, you just need aircraft/ and engine/
alongside the compiled JSBSim_SFunction.mexmaci64 in order for it to work.
You also nede to be sure that the script in the S-Function parameter is in
the correct location.
A Windows installer JSBSim-1.2.1-setup.exe is available from JSBSim release section. Download the installer and set up JSBSim in the following local directory tree
<JSBSim root>/
aeromatic++/
aircraft/
data_output/
engine/
include/
lib/
matlab/
scripts/
systems/
COPYING
JSBSim.exe
msvcp140.dllThe exact location <JSBSim root>/ on your system depends on where you choose to install JSBSim.
NOTE: The JSBSim library file located at
lib\JSBSim.libhas been compiled with Microsoft Visual Studio Enterprise 2019 (build 16.11.35026.282)
The following steps are tested for Matlab v2020b.
To compile the file <JSBSim root>/matlab/JSBSim_SFunction.cpp and get the MEX-File JSBSim_SFunction.mexw64 on Windows, you need a working C++ compiler. Among the available options, we suggest using Visual Studio Community Edition.
Once you have a working C++ development environment, you need to tell the MEX utility what is the default C++ compiler. This can be achieved by executing the following command from the Matlab command line:
[Matlab prompt]>> mex -setup CPP
MEX will detect your C++ compiler and will be configured to build your *.mexw64 files.
The MATLAB script <JSBSim root>/matlab/JSBSimSimulinkCompile.m default setting is to compile the S-Function from the folder <JSBSim root>/matlab. If needed, you can customize the script to your own needs.
Once done, change the current Matlab Working Directory to <JSBSim root>/matlab and run JSBSimSimulinkCompile.m either from the Matlab editor or from the command line:
[Matlab prompt]>> JSBSimSimulinkCompile
After the completion of the compilation you should have the following MEX-file <JSBSim root>/matlab/JSBSim_SFunction.mexw64.
To verify that the MEX file has been built successfully, we will now run the example script provided with JSBSim.
First of all, copy the script <JSBSim root>/matlab/TestJSBSim.m to the root directory <JSBSim root>. This makes sense, because we want a Matlab EXecutable (MEX) that lives besides <JSBSim root>/JSBSim.exe, and that must be able to reach all input files in the directories aircraft, engine, scripts, and systems.
Proceed with the Simulink example file ex737cruise.slx and the MEX file JSBSim_SFunction.mexw64 and copy them both from the folder <JSBSim root>/matlab/ to the root directory <JSBSim root>/.
You should now have a script <JSBSim root>/TestJSBSim.m that contains the following instructions:
disp('Run 737 example');
fprintf('Current directory: %s', pwd)
sim('ex737cruise');
clear functions;
clear all;
disp('JSBSim S-Function Reset');and this is a Simulink screenshot once the file <JSBSim root>/ex737cruise.slx is open:
In particular, this is how the Simulink block named JSBSim_SFunction appears when you double-click on it:
When you run the test script you'll get the foloowing output in the Matlab command window:
>> TestJSBSim
Run 737 example
Current directory: C:\Users\agodemar\JSBSim
Warning: 'Output Port 3' of 'ex737cruise/S-Function' is not connected.
> In TestJSBSim (line 3)
JSBSim Flight Dynamics Model v1.1.8 [GitHub build 588/commit c943f83deeb3e14bed7939ac65dfac789a7a0181] Jul 24 2021 16:18:42
[JSBSim-ML v2.0]
JSBSim startup beginning ...
Simulation dt set to 0.008333
Script input: scripts/737_cruise
Reset file: 'cruise_init' .
JSBSim S-Function is initializing...
Note: For Aircraft with integrators in the FCS, please type 'clearSF' to completely reset S-Function.
Setting up JSBSim with standard 'aircraft', 'engine', and 'system' paths.
Loading aircraft '737' ...
Reading Aircraft Configuration File: 737
Version: 2.0
This aircraft model is a BETA release!!!
This aircraft model probably will not fly as expected.
Use this model for development purposes ONLY!!!
Description: Models a Boeing 737.
Model Author: Dave Culp
Creation Date: 2006-01-04
Version: $Revision: 1.43 $
Aircraft Metrics:
WingArea: 1171
WingSpan: 94.7
Incidence: 0
Chord: 12.31
H. Tail Area: 348
H. Tail Arm: 48.04
V. Tail Area: 297
V. Tail Arm: 44.5
Eyepoint (x, y, z): 80 , -30 , 70
Ref Pt (x, y, z): 625 , 0 , 24
Visual Ref Pt (x, y, z): 0 , 0 , 0
Mass and Balance:
baseIxx: 562000 slug-ft2
baseIyy: 1.473e+06 slug-ft2
baseIzz: 1.894e+06 slug-ft2
baseIxy: -0 slug-ft2
baseIxz: 8000 slug-ft2
baseIyz: -0 slug-ft2
Empty Weight: 83000 lbm
CG (x, y, z): 639 , 0 , -40
Ground Reactions:
BOGEY Nose Gear
Location: 158 , 0 , -84
Spring Constant: 90000
Damping Constant: 4000 (linear)
Rebound Damping Constant: 8000 (linear)
Dynamic Friction: 0.5
Static Friction: 0.8
Rolling Friction: 0.02
Steering Type: STEERABLE
Grouping: NONE
Max Steer Angle: 35
Retractable: 1
BOGEY Left Main Gear
Location: 648 , -100 , -84
Spring Constant: 120000
Damping Constant: 10000 (linear)
Rebound Damping Constant: 20000 (linear)
Dynamic Friction: 0.5
Static Friction: 0.8
Rolling Friction: 0.02
Steering Type: FIXED
Grouping: LEFT
Max Steer Angle: 0
Retractable: 1
BOGEY Right Main Gear
Location: 648 , 100 , -84
Spring Constant: 120000
Damping Constant: 10000 (linear)
Rebound Damping Constant: 20000 (linear)
Dynamic Friction: 0.5
Static Friction: 0.8
Rolling Friction: 0.02
Steering Type: FIXED
Grouping: RIGHT
Max Steer Angle: 0
Retractable: 1
Propulsion:
FUEL tank holds 10200 lbs. FUEL
currently at 98.0392% of maximum capacity
Tank location (X, Y, Z): 520, -80, -18
Effective radius: 0 inches
Initial temperature: -9999 Fahrenheit
Priority: 1
FUEL tank holds 10200 lbs. FUEL
currently at 98.0392% of maximum capacity
Tank location (X, Y, Z): 520, 80, -18
Effective radius: 0 inches
Initial temperature: -9999 Fahrenheit
Priority: 1
FUEL tank holds 15000 lbs. FUEL
currently at 26.6667% of maximum capacity
Tank location (X, Y, Z): 480, 0, -18
Effective radius: 0 inches
Initial temperature: -9999 Fahrenheit
Priority: 1
2 dimensional table with 6 rows, 8 columns.
-10000.0000 0.0000 10000.0000 20000.0000 30000.0000 40000.0000 50000.0000 60000.0000
0.0000 0.0420 0.0436 0.0528 0.0694 0.0899 0.1183 0.1467 0.0000
0.2000 0.0500 0.0501 0.0335 0.0544 0.0797 0.1049 0.1342 0.0000
0.4000 0.0040 0.0047 0.0020 0.0272 0.0595 0.0891 0.1203 0.0000
0.6000 0.0000 0.0000 0.0000 0.0000 0.0276 0.0718 0.1073 0.0000
0.8000 0.0000 0.0000 0.0000 0.0000 0.0174 0.0468 0.0900 0.0000
1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0422 0.0700 0.0000
Function: propulsion/engine[0]/IdleThrust
2 dimensional table with 7 rows, 8 columns.
-10000.0000 0.0000 10000.0000 20000.0000 30000.0000 40000.0000 50000.0000 60000.0000
0.0000 1.2600 1.0000 0.7400 0.5340 0.3720 0.2410 0.1490 0.0000
0.2000 1.1710 0.9340 0.6970 0.5060 0.3550 0.2310 0.1430 0.0000
0.4000 1.1500 0.9210 0.6920 0.5060 0.3570 0.2330 0.1450 0.0000
0.6000 1.1810 0.9510 0.7210 0.5320 0.3780 0.2480 0.1540 0.0000
0.8000 1.2580 1.0200 0.7820 0.5820 0.4170 0.2750 0.1700 0.0000
1.0000 1.3690 1.1200 0.8710 0.6510 0.4750 0.3150 0.1950 0.0000
1.2000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Function: propulsion/engine[0]/MilThrust
X = 540.0000
Y = -193.0000
Z = -40.0000
Pitch = 0.0000 degrees
Yaw = 0.0000 degrees
2 dimensional table with 6 rows, 8 columns.
-10000.0000 0.0000 10000.0000 20000.0000 30000.0000 40000.0000 50000.0000 60000.0000
0.0000 0.0420 0.0436 0.0528 0.0694 0.0899 0.1183 0.1467 0.0000
0.2000 0.0500 0.0501 0.0335 0.0544 0.0797 0.1049 0.1342 0.0000
0.4000 0.0040 0.0047 0.0020 0.0272 0.0595 0.0891 0.1203 0.0000
0.6000 0.0000 0.0000 0.0000 0.0000 0.0276 0.0718 0.1073 0.0000
0.8000 0.0000 0.0000 0.0000 0.0000 0.0174 0.0468 0.0900 0.0000
1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0422 0.0700 0.0000
Function: propulsion/engine[1]/IdleThrust
2 dimensional table with 7 rows, 8 columns.
-10000.0000 0.0000 10000.0000 20000.0000 30000.0000 40000.0000 50000.0000 60000.0000
0.0000 1.2600 1.0000 0.7400 0.5340 0.3720 0.2410 0.1490 0.0000
0.2000 1.1710 0.9340 0.6970 0.5060 0.3550 0.2310 0.1430 0.0000
0.4000 1.1500 0.9210 0.6920 0.5060 0.3570 0.2330 0.1450 0.0000
0.6000 1.1810 0.9510 0.7210 0.5320 0.3780 0.2480 0.1540 0.0000
0.8000 1.2580 1.0200 0.7820 0.5820 0.4170 0.2750 0.1700 0.0000
1.0000 1.3690 1.1200 0.8710 0.6510 0.4750 0.3150 0.1950 0.0000
1.2000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Function: propulsion/engine[1]/MilThrust
X = 540.0000
Y = 193.0000
Z = -40.0000
Pitch = 0.0000 degrees
Yaw = 0.0000 degrees
FCS: FCS: 737
Channel Pitch
Loading Component "Pitch Trim Sum" of type: SUMMER
Minimum limit: -1.000000
Maximum limit: 1.000000
INPUTS:
elevator-cmd-norm
pitch-trim-cmd-norm
OUTPUT: pitch-trim-sum
Loading Component "Elevator Control" of type: AEROSURFACE_SCALE
INPUT: pitch-trim-sum
GAIN: constant value 1.000000
OUTPUT: elevator-pos-rad
OUTPUT: elevator-control
In/Out Mapping:
Input MIN: -1.0000
Input MAX: 1.0000
Output MIN: -0.3000
Output MAX: 0.3000
Loading Component "Elevator Normalized" of type: AEROSURFACE_SCALE
INPUT: elevator-pos-rad
GAIN: constant value 1.000000
OUTPUT: elevator-pos-norm
OUTPUT: elevator-normalized
In/Out Mapping:
Input MIN: -0.3000
Input MAX: 0.3000
Output MIN: -1.0000
Output MAX: 1.0000
Channel Roll
Loading Component "Roll Trim Sum" of type: SUMMER
Minimum limit: -1.000000
Maximum limit: 1.000000
INPUTS:
aileron-cmd-norm
roll-trim-cmd-norm
OUTPUT: roll-trim-sum
Loading Component "Left Aileron Control" of type: AEROSURFACE_SCALE
INPUT: roll-trim-sum
GAIN: constant value 1.000000
OUTPUT: left-aileron-pos-rad
OUTPUT: left-aileron-control
In/Out Mapping:
Input MIN: -1.0000
Input MAX: 1.0000
Output MIN: -0.3500
Output MAX: 0.3500
Loading Component "Right Aileron Control" of type: AEROSURFACE_SCALE
INPUT: -roll-trim-sum
GAIN: constant value 1.000000
OUTPUT: right-aileron-pos-rad
OUTPUT: right-aileron-control
In/Out Mapping:
Input MIN: -1.0000
Input MAX: 1.0000
Output MIN: -0.3500
Output MAX: 0.3500
Loading Component "Left aileron Normalized" of type: AEROSURFACE_SCALE
INPUT: left-aileron-pos-rad
GAIN: constant value 1.000000
OUTPUT: left-aileron-pos-norm
OUTPUT: left-aileron-normalized
In/Out Mapping:
Input MIN: -0.3500
Input MAX: 0.3500
Output MIN: -1.0000
Output MAX: 1.0000
Loading Component "Right aileron Normalized" of type: AEROSURFACE_SCALE
INPUT: right-aileron-pos-rad
GAIN: constant value 1.000000
OUTPUT: right-aileron-pos-norm
OUTPUT: right-aileron-normalized
In/Out Mapping:
Input MIN: -0.3500
Input MAX: 0.3500
Output MIN: -1.0000
Output MAX: 1.0000
Channel Yaw
Loading Component "Rudder Command Sum" of type: SUMMER
Minimum limit: -1.000000
Maximum limit: 1.000000
INPUTS:
rudder-cmd-norm
yaw-trim-cmd-norm
OUTPUT: rudder-command-sum
Loading Component "Yaw Damper" of type: SCHEDULED_GAIN
1 dimensional table with 3 rows.
0.0000 0.0000
0.1000 0.0000
0.1100 1.0000
INPUT: r-aero-rad_sec
GAIN: constant value 1.000000
OUTPUT: yaw-damper
Scheduled by table:
1 dimensional table with 3 rows.
0.0000 0.0000
0.1000 0.0000
0.1100 1.0000
Loading Component "Yaw Damper Final" of type: SCHEDULED_GAIN
1 dimensional table with 3 rows.
0.0000 0.0000
0.1000 0.0000
0.1100 1.0000
INPUT: yaw-damper
GAIN: constant value 1.000000
OUTPUT: yaw-damper-final
Scheduled by table:
1 dimensional table with 3 rows.
0.0000 0.0000
0.1000 0.0000
0.1100 1.0000
Loading Component "Rudder Sum" of type: SUMMER
Minimum limit: -1.000000
Maximum limit: 1.000000
INPUTS:
rudder-command-sum
yaw-damper-final
OUTPUT: rudder-sum
Loading Component "Rudder Control" of type: AEROSURFACE_SCALE
INPUT: rudder-sum
GAIN: constant value 1.000000
OUTPUT: rudder-pos-rad
OUTPUT: rudder-control
In/Out Mapping:
Input MIN: -1.0000
Input MAX: 1.0000
Output MIN: -0.3500
Output MAX: 0.3500
Loading Component "Rudder Normalized" of type: AEROSURFACE_SCALE
INPUT: rudder-pos-rad
GAIN: constant value 1.000000
OUTPUT: rudder-pos-norm
OUTPUT: rudder-normalized
In/Out Mapping:
Input MIN: -0.3500
Input MAX: 0.3500
Output MIN: -1.0000
Output MAX: 1.0000
Channel Flaps
Loading Component "Flaps Control" of type: KINEMATIC
INPUT: flap-cmd-norm
DETENTS: 9
0.0000 0.0000
0.1250 5.0000
0.2500 4.0000
0.3750 3.0000
0.5000 2.0000
0.6250 2.0000
0.7500 2.0000
0.8750 2.0000
1.0000 2.0000
OUTPUT: flap-pos-norm
OUTPUT: flaps-control
Channel Landing Gear
Loading Component "Gear Control" of type: KINEMATIC
INPUT: gear-cmd-norm
DETENTS: 2
0.0000 0.0000
1.0000 5.0000
OUTPUT: gear-pos-norm
OUTPUT: gear-control
Channel Flight Spoilers
Loading Component "Flight Spoilers Control" of type: KINEMATIC
INPUT: speedbrake-cmd-norm
DETENTS: 2
0.0000 0.0000
1.0000 0.6000
OUTPUT: speedbrake-pos-norm
OUTPUT: flight-spoilers-control
Channel Ground Spoilers
Loading Component "Ground Spoilers Control" of type: KINEMATIC
INPUT: spoiler-cmd-norm
DETENTS: 2
0.0000 0.0000
1.0000 0.6000
OUTPUT: spoiler-pos-norm
OUTPUT: ground-spoilers-control
1 dimensional table with 10 rows.
0.0000 0.0480
0.1000 0.5150
0.1500 0.6290
0.2000 0.7090
0.3000 0.8150
0.4000 0.8820
0.5000 0.9280
0.6000 0.9620
0.7000 0.9880
0.8000 1.0000
Function: aero/function/kCDge
1 dimensional table with 13 rows.
0.0000 1.2030
0.1000 1.1270
0.1500 1.0900
0.2000 1.0730
0.3000 1.0460
0.4000 1.0280
0.5000 1.0190
0.6000 1.0130
0.7000 1.0080
0.8000 1.0060
0.9000 1.0030
1.0000 1.0020
1.1000 1.0000
Function: aero/function/kCLge
1 dimensional table with 2 rows.
0.0000 1.0000
0.1000 0.8500
Function: aero/function/kCLsb
1 dimensional table with 2 rows.
0.0000 1.0000
0.1000 0.6000
Function: aero/function/kCLsp
Aerodynamics (Lift|Side|Drag axes):
1 dimensional table with 5 rows.
-1.5700 1.5000
-0.2600 0.0420
0.0000 0.0210
0.2600 0.0420
1.5700 1.5000
Function: aero/coefficient/CD0
Function: aero/coefficient/CDi
1 dimensional table with 4 rows.
0.0000 0.0000
0.7900 0.0000
1.1000 0.0230
1.8000 0.0150
Function: aero/coefficient/CDmach
Function: aero/coefficient/CDflap
Function: aero/coefficient/CDgear
Function: aero/coefficient/CDsb
Function: aero/coefficient/CDsp
1 dimensional table with 5 rows.
-1.5700 1.2300
-0.2600 0.0500
0.0000 0.0000
0.2600 0.0500
1.5700 1.2300
Function: aero/coefficient/CDbeta
Function: aero/coefficient/CDde
Function: aero/coefficient/CYb
1 dimensional table with 4 rows.
-0.2000 -0.6800
0.0000 0.2000
0.2300 1.2000
0.4600 0.2000
Function: aero/coefficient/CLalpha
Function: aero/coefficient/dCLflap
Function: aero/coefficient/CLde
Function: aero/coefficient/Clb
Function: aero/coefficient/Clp
Function: aero/coefficient/Clr
1 dimensional table with 2 rows.
0.0000 0.1000
2.0000 0.0330
Function: aero/coefficient/Clda
Function: aero/coefficient/Cldr
Function: aero/coefficient/Cmalpha
1 dimensional table with 2 rows.
0.0000 -1.2000
2.0000 -0.3000
Function: aero/coefficient/Cmde
Function: aero/coefficient/Cmq
Function: aero/coefficient/Cmadot
Function: aero/coefficient/Cnb
Function: aero/coefficient/Cnr
Function: aero/coefficient/Cndr
Input data set: 0
Input data set: 1
Declared properties
In file aircraft/737/737.xml: line 911
Property fcs/aileron-cmd-norm is already defined.
In file aircraft/737/737.xml: line 912
Property fcs/elevator-cmd-norm is already defined.
In file aircraft/737/737.xml: line 913
Property fcs/rudder-cmd-norm is already defined.
In file aircraft/737/737.xml: line 914
Property fcs/throttle-cmd-norm[0] is already defined.
In file aircraft/737/737.xml: line 915
Property fcs/throttle-cmd-norm[1] is already defined.
In file aircraft/737/737.xml: line 916
Property simulation/terminate is already defined.
Model 737 loaded.
'737' Aircraft File has been successfully loaded!
Winsock DLL loaded ...
Creating input TCP socket on port 5137
Successfully bound to TCP input socket on port 5137
Winsock DLL loaded ...
Creating input UDP socket on port 5139
Successfully bound to UDP input socket on port 5139
Mass Properties Report (English units: lbf, in, slug-ft^2)
Weight CG-X CG-Y CG-Z Ixx Iyy Izz Ixy Ixz Iyz
Base Vehicle 83000.0 639.0 0.0 -40.0 562000.0 1473000.0 1894000.0 -0.0 8000.0 -0.0
0 Fuel 10000 520 -80 -18 0 0 0
1 Fuel 10000 520 80 -18 0 0 0
2 Fuel 4000 480 0 -18 0 0 0
Total: 107000.0 610.8 0.0 -35.1 591572.3 1539552.7 1986235.4 0.0 19109.1 0.0
End of vehicle configuration loading.
-------------------------------------------------------------------------------
Simulation completed.
Remember to reset the program by typing clearSF in the matlab command window!
JSBSim S-Function Resetand in Simulink you'll have the following outputs:
So you just have to try it out and adapt this workflow to your needs.
The JSBSim interface with MATLAB including the S-Function is open source and is licensed under the BSD license. The license is included in the source code file LICENSE.txt.