import jsbsim import time # Create a simulation executive instance fdm = jsbsim.FGAExec(root_dir=".") # Load the aircraft and initialization files fdm.load_model("c172") fdm.load_ic("reset00", True) # Initialize the run fdm.run_ic() # Time loop execution step while fdm.run(): sim_time = fdm.get_sim_time() alt = fdm.get_property_value("position/h-sl-ft") airspeed = fdm.get_property_value("velocities/vc-kts") if int(sim_time) % 5 == 0: print(f"Time: sim_time:.2fs | Altitude: alt:.1f ft | Speed: airspeed:.1f kts") # Introduce an automated throttle down event at 20 seconds if sim_time > 20.0: fdm.set_property_value("fcs/throttle-cmd-norm", 0.5) Use code with caution.
Processes pilot inputs (stick, rudder, throttle) through components like filters, gains, and summers to output surface deflections.
<simulation> <duration>100</duration> <dt>0.01</dt> <gravity>9.81</gravity> </simulation>
JSBSim models are defined using . A complete model includes several key sections:
The initialization file ( reset_state.xml ) specifies the initial conditions: jsbsim tutorial
Once your XML configuration files are saved in their respective directories ( aircraft/ , scripts/ , init/ ), execute JSBSim using your terminal: jsbsim --script=scripts/run_test.xml Use code with caution. Output Data Logging
that reads XML files to calculate how an aircraft moves through space. The system relies on three main components: The Executive:
A standard JSBSim simulation is driven by a series of interconnected XML configurations. Understanding how these files interact is key to mastering the software.
The "brain" that manages the simulation time steps and loops. The Models: import jsbsim import time # Create a simulation
<?xml version="1.0"?> <runscript> <use aircraft="c172p" initialize="reset01"/> <run start="0" end="200" dt="0.01"> <event name="Engine Start"> <condition> simulation/sim-time-sec ge 0.0 </condition> <set name="propulsion/engine[0]/set-running" value="1"/> </event> </run> </runscript>
An Introduction to JSBSim: Mastering Flight Dynamics Modeling
: Works as the physics engine for visual environments like FlightGear , Unreal Engine , or PX4 Autopilot . Core Components and File Structure
For users on Ubuntu Linux "Jammy" 22.04 LTS and "Noble" 24.04 LTS, or other Debian-based systems, pre-built .deb packages are the easiest method: A complete model includes several key sections: The
: JSBSim is multi-platform and can be installed via a Windows installer (e.g., version 1.3) or built from source using CMake on Linux, macOS, and other Unix-like systems.
: Use , , and components inside the system config to build autopilots or fly-by-wire mechanics.
To start using JSBSim, you'll need to:
Empty weight, inertia moments, and center of gravity (CG).
flag if you want the simulation to run at actual speed rather than as fast as your CPU allows. 4. Creating a Custom Aircraft Starting from scratch is hard. Instead, use
