5a0082b6ed
* fix(fw_mode_manager): honor DO_CHANGE_SPEED in manual airspeed modes Re-anchor the throttle-stick airspeed interpolation on the last MAV_CMD_DO_CHANGE_SPEED value (falling back to FW_AIRSPD_TRIM if none). Previously, _commanded_manual_airspeed_setpoint was stored but never read when FW_POS_STK_CONF bit 1 was set (the default), so DO_CHANGE_SPEED had no effect in Position/Altitude. With this change: - Stick centered = commanded cruise speed (= FW_AIRSPD_TRIM if no command). - Stick deflection deviates from cruise between FW_AIRSPD_MIN/MAX. - Disconnecting the controller collapses the interpolation to the cruise (Sticks zeroes the throttle channel on manual_control_signal_lost). - No setpoint jump when a controller is plugged in with stick centered. - No behavior change for users who never send DO_CHANGE_SPEED. * fix(fw_mode_manager): clear DO_CHANGE_SPEED override on mode change Reset _commanded_manual_airspeed_setpoint to NaN when entering a manual airspeed mode from outside the manual airspeed pair, so a prior MAV_CMD_DO_CHANGE_SPEED does not silently anchor the manual airspeed setpoint after the pilot has left and re-entered manual airspeed control. Toggling between Position and Altitude preserves the commanded value since both modes share the same airspeed mechanic. Also fold in a make-format whitespace fix in get_manual_airspeed_setpoint. * docs(flight_modes_fw): document DO_CHANGE_SPEED in manual airspeed modes Describe how MAV_CMD_DO_CHANGE_SPEED re-anchors the throttle-stick cruise airspeed in Position and Altitude mode, matching the new behavior in the fw_mode_manager. Covers the centered-stick anchor, deflection scaling between FW_AIRSPD_MIN/MAX, the shared setpoint across both modes, and the reset to trim when entering from any other mode. Signed-off-by: Gregor Hohl <gregor.hohl@auterion.com> * Subedit * fix(fw_mode_manager): reset DO_CHANGE_SPEED override on any mode change Reset _commanded_manual_airspeed_setpoint to NaN whenever the position control mode changes, instead of only when entering manual airspeed control from outside the Position/Altitude pair. This makes the manual airspeed setpoint revert to FW_AIRSPD_TRIM on every mode change, including toggling between Position and Altitude, for predictable behavior. Signed-off-by: Gregor Hohl <gregor.hohl@auterion.com> * docs(flight_modes_fw): note manual airspeed resets on mode change Clarify that the commanded airspeed defaults to FW_AIRSPD_TRIM when no airspeed has been commanded, and document that the commanded airspeed resets on every flight mode change. Signed-off-by: Gregor Hohl <gregor.hohl@auterion.com> * docs(flight_modes_fw): clarify DO_CHANGE_SPEED param1/param2 handling Signed-off-by: Gregor Hohl <gregor.hohl@auterion.com> --------- Signed-off-by: Gregor Hohl <gregor.hohl@auterion.com> Co-authored-by: Hamish Willee <hamishwillee@gmail.com>
The autopilot stack the industry builds on.
About
PX4 is an open-source autopilot stack for drones and unmanned vehicles. It supports multirotors, fixed-wing, VTOL, rovers, and many more experimental platforms from racing quads to industrial survey aircraft. It runs on NuttX, Linux, and macOS. Licensed under BSD 3-Clause.
Why PX4
Modular architecture. PX4 is built around uORB, a DDS-compatible publish/subscribe middleware. Modules are fully parallelized and thread safe. You can build custom configurations and trim what you don't need.
Wide hardware support. PX4 runs on a wide range of autopilot boards and supports an extensive set of sensors, telemetry radios, and actuators through the Pixhawk ecosystem.
Developer friendly. First-class support for MAVLink and DDS / ROS 2 integration. Comprehensive SITL simulation, hardware-in-the-loop testing, and log analysis tools. An active developer community on Discord and the weekly dev call.
Vendor neutral governance. PX4 is hosted under the Dronecode Foundation, part of the Linux Foundation. Business-friendly BSD-3 license. No single vendor controls the roadmap.
Supported Vehicles
 Multicopter |
 Fixed Wing |
 VTOL |
 Rover |
…and many more: helicopters, autogyros, airships, submarines, boats, and other experimental platforms. These frames have basic support but are not part of the regular flight-test program. See the full airframe reference.
Try PX4
Run PX4 in simulation with a single command. No build tools, no dependencies beyond Docker:
docker run --rm -it -p 14550:14550/udp px4io/px4-sitl:latest
Open QGroundControl and fly. See PX4 Simulation Quickstart for more options.
Build from Source
git clone https://github.com/PX4/PX4-Autopilot.git --recursive
cd PX4-Autopilot
make px4_sitl
Note
See the Development Guide for toolchain setup and build options.
Documentation & Resources
| Resource | Description |
|---|---|
| User Guide | Build, configure, and fly with PX4 |
| Developer Guide | Modify the flight stack, add peripherals, port to new hardware |
| Airframe Reference | Full list of supported frames |
| Autopilot Hardware | Compatible flight controllers |
| Release Notes | What's new in each release |
| Contribution Guide | How to contribute to PX4 |
Community
- Weekly Dev Call — open to all developers (Dronecode calendar)
- Discord — Join the Dronecode server
- Discussion Forum — PX4 Discuss
- Maintainers — see
MAINTAINERS.md - Contributor Stats — LFX Insights
Contributing
We welcome contributions of all kinds — bug reports, documentation, new features, and code reviews. Please read the Contribution Guide to get started.
Citation
If you use PX4 in academic work, please cite it. BibTeX:
@software{px4_autopilot,
author = {Meier, Lorenz and {The PX4 Contributors}},
title = {{PX4 Autopilot}},
publisher = {Zenodo},
doi = {10.5281/zenodo.595432},
url = {https://px4.io}
}
The DOI above is a Zenodo concept DOI that always resolves to the latest release. For a version-pinned citation, see the Zenodo record or our CITATION.cff.
Governance
The PX4 Autopilot project is hosted by the Dronecode Foundation, a Linux Foundation Collaborative Project. Dronecode holds all PX4 trademarks and serves as the project's legal guardian, ensuring vendor-neutral stewardship — no single company owns the name or controls the roadmap. The source code is licensed under the BSD 3-Clause license, so you are free to use, modify, and distribute it in your own projects.
