UISC Lab Px4Ctrl Client

Zenoh + ImGui Ground Control Station for px4ctrl

px4ctrl_client is a lightweight desktop GCS for px4ctrl.

• Mission commands: ARM, ENTER_OFFBOARD, TAKEOFF, LAND, FORCE_HOVER, FORCE_DISARM, ALLOW_CMD_CTRL.
• Hover target editing and publish (CHANGE_HOVER_POS).
• Online safety update (SET_SAFETY_LIMITS).
• Status panel with highlighted Offboard and Armed states.
• XY position trace with optional geofence box overlay.
• X/Y/Z and control command time-series plots with axis ticks and second-based time axis.
• Keyboard piloting with configurable velocity.
• Colored logs by log level (trace/debug/info/warn/error/critical).

• C++20 compiler
• spdlog
• OpenGL
• glfw3
• pkg-config
• zenoh-c

git clone https://github.com/Luxru/px4ctrl_client.git
cd px4ctrl_client
git submodule update --init --recursive
mkdir -p build
cd build
cmake ..
make -j4

./px4client -c ../config/zenoh.json

Default config file:

• config/zenoh.json

Example:

{
  "backend": "zenoh",
  "server_topic": "px4s",
  "client_topic": "px4c",
  "log_topic": "px4log",
  "zenoh": {
    "mode": "peer",
    "connect": "",
    "listen": "",
    "multicast_scouting": true,
    "scouting_timeout_ms": 1000
  },
  "keyboard": {
    "vel_xy": 1.0,
    "vel_z": 0.2,
    "vel_yaw": 2.0
  }
}

Notes:

• listen default is empty to reduce local port conflicts.
• connect can stay empty when scouting is enabled in the same network.
• telemetry_hz can be configured in the same JSON (default: 200).

Keyboard listener is per drone card and must be activated from the UI.

Keys:

• W/S/A/D: move hover target in XY.
• R/F: move up/down.
• Q/E: yaw increase/decrease.
• C: toggle BODY/WORLD control frame.
• Space: send FORCE_HOVER.
• J: send FORCE_DISARM.
• L: send LAND.

Velocity sources:

• Initial values from config/zenoh.json -> keyboard.
• Runtime adjustment from ImGui panel.

Safety panel supports:

• Enable Geofence
• Geofence Min/Max
• Enable Attitude Fence
• Max Roll Deg, Max Pitch Deg, Max Yaw Deg

Limit rule:

• -1 means unlimited.
• Otherwise each limit must be in (0, 180].

When server-side guard.use_rc = true:

• Client will still show telemetry/logs normally.
• ARM/DISARM/OFFBOARD related commands can be rejected by server policy.
• Server expects RC/PX4 mode switching for those operations.

• Failed to open zenoh session:
  • Check zenohc installation and runtime library path.
  • Try listen: "" and keep only connect or scouting.
• No telemetry displayed:
  • Verify topic names and that server/client use the same transport JSON fields.
• Unexpected decode/ABI issues:
  • Ensure client and server are built from matching message struct versions.

Xu Lu - lux@cqu.edu.cn

• ZJU FastLab
• UZH Robotics and Perception Group