PX4 command

Introduction

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

Documents

• Manual
• External Command API
• Qt

To Do

Complete Docs

Installation

# Create Catkin Workspace in home
mkdir -p ~/px4_ws/src 
cd ~/px4_ws/src
catkin_init_workspace
# 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 $(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.

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

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

@software{Yi_px4_cmd_2024,
author = {Yi, Peng},
month = apr,
title = {{px4_cmd}},
url = {https://github.com/Lovely-XPP/px4_cmd},
version = {2.0.0},
doi = https://zenodo.org/doi/10.5281/zenodo.10998013
year = {2024}
}

Credits

• PX4-Autopilot
• PX4 Guide