Hi everyone,
I’d like to share an open-source project I’ve been working on that might interest
anyone doing SITL/HITL work: PX4-FlightAxis-Bridge, which connects PX4 Autopilot
to RealFlight Evolution over the FlightAxis Link protocol.
Why
RealFlight Evolution is one of the most realistic RC simulators I’ve used. I’ve
tested it across models of very different sizes, comparing each simulated model
against its real-world counterpart — from full manual aerobatics to autonomous
missions. Running ArduPilot (which already has a FlightAxis backend), the results
were remarkably close to reality: build the model faithfully, and even the same
tuning parameters carried over from sim to the real aircraft.
PX4 ships in-tree bridges for Gazebo and jMAVSim, but not for RealFlight — so I
built one.
What it is
The bridge is wired into the PX4 tree: it compiles with the PX4 make system and
launches like the built-in simulators, with a single make command. QGC connects on
UDP 14550 as usual; RealFlight runs on a separate Windows box on the same wired
network.
- 18 airframes: planes, multirotors (quad through dodeca), quadplanes, hexas,
helicopters - SITL + HITL (against a real flight-controller board)
- ROS 2 offboard control (uXRCE-DDS)
- One-command install into an existing PX4 v1.16 checkout, with a clean uninstall
that reverses every change - Targets PX4 v1.16.0, GPLv3, fully documented
So far I’ve flown plane, quadplane, helicopter, and an octo-coaxial multirotor on
it, from manual sticks through automated missions.
Honest limitations
The four tilt/servo/coaxial frames (tiltrotor, tailsitter, tricopter, coaxial heli)
build and run, but their channel maps and gains are still lifted from PX4 defaults
and not yet validated against real RealFlight models — testers there especially
welcome.
More than a tool, this was a way for me to learn PX4 internals and flight dynamics.
Feedback, questions, and contributions are very welcome.
Thanks!