PX4 command

Introduction

PX4 command sent via terminal (based on mavros), providing simple API to set user-define Command to PX4 for simulation and hardware.

Documents

• Manual
• External Command API

Dependencies

• PX4-Autopilot
• mavros
• tf2

Installation

```bash

Create Catkin Workspace in home

mkdir -p ~/px4ws/src cd ~/px4ws/src catkininitworkspace

Clone this Repo

git clone https://github.com/Lovely-XPP/px4_cmd.git

make

cd .. catkin_make install

Add Source for the project

echo "source ~/px4_ws/devel/setup.bash" >> ~/.bashrc

update terminal

source ~/.bashrc ```

Run Simulation

bash bash $(rospack find px4_cmd)/sh/sim.sh # Sim without camera (Multicopter) bash $(rospack find px4_cmd)/sh/sim_cam.sh # Sim with camera (Multicopter) bash $(rospack find px4_cmd)/sh/sim_fix.sh # Sim without camera (Fixwing) bash $(rospack find px4_cmd)/sh/sim_fix_cam.sh # Sim with camera (Fixwing) More Detailed Information is on Wiki.

Real Experiment

rosrun px4_cmd set_mode rosrun px4_cmd send_cmd rosrun px4_cmd set_cmd

About Offboard Mode

If you have problem for changing mode to Offboard Mode, please check the offical instruction:

Note for Offboard Mode - This mode requires position or pose/attitude information - e.g. GPS, optical flow, visual-inertial odometry, mocap, etc. - RC control is disabled except to change modes. - The vehicle must be armed before this mode can be engaged. - The vehicle must be already be receiving a stream of target setpoints (>2Hz) before this mode can be engaged. - The vehicle will exit the mode if target setpoints are not received at a rate of > 2Hz. - Not all coordinate frames and field values allowed by MAVLink are supported.

More details in https://docs.px4.io/main/en/flight_modes/offboard.html.

About PX4 V1.13.0 or Newer Version

Tips: If you are using PX4 V1.13.0 or newer, you can not set to Offboard Mode in simulation, because Offboard Mode can not be enabled without RC signal in newer version.

Relevant Code

PX4-Autopilot/src/modules/commander/state_machine_helper.cpp: 632

cpp else if (status.rc_signal_lost && !(param_com_rcl_except & RCLossExceptionBits::RCL_EXCEPT_OFFBOARD)) { // Only RC is lost enable_failsafe(status, old_failsafe, mavlink_log_pub, event_failsafe_reason_t::no_rc); set_link_loss_nav_state(status, armed, status_flags, internal_state, rc_loss_act, param_com_rcl_act_t); }

Therefore, even if we provide stable Offboard Command (publish to /mavros/setpoints_raw/local, > 2 Hz), we still can not enable the Offboard Mode if We do not have RC signal.

Temporary Solution

1. If you don't want to connet a RC controller for simulation, you can delete the code shown above, but it ONLY FOR Simulation USE, DO NOT For Real Vehicle USE.
2. Downgrade PX4 Version to V1.12.3 and below.

Citation

If you use this software, please cite it as below. bibtex @software{yi_2025_15005321, author = {Yi, Peng}, title = {Lovely-XPP/px4\_cmd\_basic: px4\_cmd V2.2.1}, month = mar, year = 2025, publisher = {Zenodo}, version = {v2.2.1}, doi = {10.5281/zenodo.15005321}, url = {https://doi.org/10.5281/zenodo.15005321}, }

Credits

• PX4-Autopilot
• PX4 Guide