State of JSBSim SITL for fixed-wing (Rascal model)

simfinite · February 9, 2025, 8:04pm

Hi there,

trying to run a JSBSim SITL as per documentation, I seem to be facing several issues:

known bug regarding regarding number of simulated accelerometers, fixed as suggested here: https://github.com/Auterion/px4-jsbsim-bridge/pull/66
preflight checks report “height estimate not stable”
when commanding a take-off or switching to manual, the plane rolls over / crashes quickly. Looking at a JSBSim CSV log, it seems the engine is seeing a large step in RPM at the time of the mode switch.

This was tested with PX4 v1.15.3 (also tried 1.16-alpha2) and JSBSim versions 1.1.0 (first one supporting Jammy) and v1.2.1 (latest release).

Attached are output of “make px4_sitl jsbsim” command, PX4 ulog and JSBSim CSV log. I am looking for some feedback if anyone reproduces these issues and tips on what to look into. I would be happy to open and work on issues on a repository (PX4 firmware, JSBSim bridge, Rascal model, …) once I have some more infos on this.

Here is a zip with the logs: https://filedn.eu/lFK71hM6HqNfQErsmMLIGC4/px4_jsbsim_sitl_fail_logs.zip

Looking forward to any help, thank you.

simfinite · February 10, 2025, 7:39pm

Adding to the log of issues:

when first running `make px4_sitl jsbsim", CMake fails to find Mavlink headers. A work-around is to build JMavSim simulation once. Afterwards, the JSBSim build runs through.
flight gear bridge seems to have the same problem discussed at Added sensor_msg.id to avoid out of range error from PX4's SimulatorMavlink by toshiharutf · Pull Request #66 · Auterion/px4-jsbsim-bridge · GitHub . Work-around is to to add a new line sensor_msg.id = 0; in file vehicle_state.cpp in function VehicleState::getSensorMsg

On the plus side, I could successfully run both YaSim and JSBSim Rascal models via FlightGear. For my purposes, however, I need “native” JSBSim version with lockstep mechanism.