Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Nereo PoliTOcean

Code for the Nereo ROV by PoliTOcean.

The project is split into two ROS 2 (Humble) workspaces:

Workspace	Side	Purpose
`gui_ws`	Control station (PC)	GUI, joystick, web controller, safety arbitration
`rpi_ws`	Raspberry Pi (on the ROV)	IMU / barometer / sonar acquisition

The PID/state-space controller lives in a separate repository, ros2_controller_tuning_aid, and is wired in by the workstation.launch.py of gui_pkg.

Installation

0. Clone the repos

nereo_interfaces is a git submodule of this repo. Clone with --recurse-submodules:

git clone --recurse-submodules https://github.com/PoliTOcean/nereo_ros2_code.git

If already cloned without it:

git submodule update --init

Clone the controller repo next to this one (paths in workstation.launch.py assume they are siblings under ~/Documents/PoliTOcean/RD/):

git clone https://github.com/PoliTOcean/ros2_controller_tuning_aid.git

1. System dependencies

sudo apt update
sudo apt install \
ros-humble-rosbridge-suite \
ros-humble-tf-transformations \
gstreamer1.0-plugins-good gstreamer1.0-plugins-base gstreamer1.0-tools \
python3-qrcode python3-pil

Package	Used by	Why it's needed
`ros-humble-rosbridge-suite`	`web_pkg`	WebSocket bridge for the web controller (port 9090)
`ros-humble-tf-transformations`	`gui_pkg`	Quaternion → RPY conversion in the GUI
`gstreamer1.0-plugins-*`	`gui_pkg`	Live H.264/UDP video from the ROV cameras
`python3-qrcode`, `python3-pil`	`gui_pkg`	Generates the QR code shown on `Ctrl+Q` for the web controller URL

2. PyQt6 with QML bindings (pip)

The apt python3-pyqt6 package ships without QtQml/QtQuick. Install via pip:

pip install PyQt6

3. Register the custom rosdep sources

A few dependencies (PyQt6, bluerobotics-ping) are not in the default rosdep index. The local override sits at rosdep.yaml in this repo:

echo"yaml file://$(pwd)/rosdep.yaml"| sudo tee /etc/ros/rosdep/sources.list.d/nereo.list
rosdep update

4. Install per-package dependencies

# Control station (PC)cd gui_ws
rosdep install --from-paths src --ignore-src -r -y
# Raspberry Picd ../rpi_ws
rosdep install --from-paths src --ignore-src -r -y

Build

# Controller (must be built first — gui_ws launch file pulls it in via AMENT_PREFIX_PATH)cd ../ros2_controller_tuning_aid && colcon build &&source install/setup.zsh
# Control stationcd ../nereo_ros2_code/gui_ws && colcon build &&source install/setup.zsh
# Raspberry Picd ../rpi_ws && colcon build &&source install/setup.zsh

Run

A single launch file starts everything on the workstation: joystick driver, command translator, GUI, safety arbiter, rosbridge WebSocket (port 9090), web controller server (port 8080), and the controller node.

ros2 launch gui_pkg workstation.launch.py

The launch file auto-prepends the ros2_controller_tuning_aid install dir to AMENT_PREFIX_PATH, so you do not need to source that overlay manually.

Launch arguments

Argument	Default	Description
`device`	`/dev/input/js0`	Joystick device path
`deadzone`	`0.05`	Joystick deadzone
`max_steps`	`10`	Quantization steps for axes
`btn_arm`	`8`	Arm/disarm button index
`btn_mode`	`6`	Direct ↔ Controller mode toggle button index
`control_mode`	`0`	Initial controller mode (0=passthrough, 1=PID, 2=PID-AW, 3=CS)

Physical controller mapping

Input	Action	Xbox One S (default)	DS5
Left stick Y/X	Surge / Sway	—	—
Right stick Y/X	Heave / Yaw	—	—
D-pad up/down	Pitch trim	—	—
D-pad left/right	Roll trim	—	—
Arm/Disarm	Toggle arm	Xbox (btn 8)	PS (btn 10)
Mode toggle	Direct ↔ Controller	View (btn 6)	Share (btn 8)

Examples:

# DS5 button mapping
ros2 launch gui_pkg workstation.launch.py btn_arm:=10 btn_mode:=8
# Different joystick device
ros2 launch gui_pkg workstation.launch.py device:=/dev/input/js1

Direct mode (red lock icon in GUI): commands go to /nereo_cmd_vel_joy → safety_node → ROV. Controller mode (blue lock icon in GUI): commands go to /nereo_cmd_vel_no_fb → controller node → safety_node → ROV.

Workspace structure

nereo_ros2_code/
├── gui_ws/ # Workstation workspace
│ └── src/
│ ├── gui_pkg/ # QML/PyQt6 dashboard + joystick + rov simulator
│ │ ├── gui_pkg/
│ │ │ ├── gui_node.py # Main node + ROSQmlBridge / SonarBridge / ControllerBridge
│ │ │ ├── rov_sim_node.py # Full ROV simulator (IMU, barometer, cameras, joy)
│ │ │ └── qml/ # QML UI
│ │ │ ├── main.qml
│ │ │ └── components/
│ │ │ ├── ControllerTunerWindow.qml # PID/CS tuning UI (deg/m setpoints)
│ │ │ ├── ControlPanelWindow.qml
│ │ │ ├── SonarWindow.qml
│ │ │ ├── Orientation2D.qml
│ │ │ └── VideoBox.qml
│ │ └── launch/
│ │ └── workstation.launch.py
│ ├── joystick_pkg/ # joy → CommandVelocity
│ ├── web_pkg/
│ │ ├── web_server_node.py # HTTP server on :8080
│ │ ├── safety_node.py # Arbitrates physical vs. web commands
│ │ └── static/ # Web controller UI assets
│ └── nereo_interfaces/ # CommandVelocity, ThrusterStatuses (submodule)
└── rpi_ws/ # Raspberry Pi workspace
└── src/
├── nereo_sensors_pkg/ # C++ — IMU (WT61P) + barometer (MS5837)
│ ├── src/imuPub.cpp # publishes /imu_data, service imu_reset_reference
│ ├── src/barPub.cpp # publishes /barometer_*, service barometer_reset_reference
│ └── include/nereo_sensors_pkg/
└── sonar_pkg/ # Python — Blue Robotics Ping1D

ROS 2 node and topic map

Nodes

Node	Package	Side	Role
`imu_publisher`	`nereo_sensors_pkg`	RPi	WT61P over I2C → `/imu_data`; service `imu_reset_reference`
`bar_publisher`	`nereo_sensors_pkg`	RPi	MS5837 over I2C → `/barometer_*`; service `barometer_reset_reference`
`sonar_node`	`sonar_pkg`	RPi	Ping1D over serial → `/sonar/*`
`gui_node`	`gui_pkg`	PC	QML dashboard, telemetry fusion, QR code, tuner
`joy_to_cmd_vel`	`joystick_pkg`	PC	Joystick → `CommandVelocity`
`safety_node`	`web_pkg`	PC	Arbitrates controller + web commands → `/nereo_cmd_vel`
`web_server_node`	`web_pkg`	PC	Serves the web controller on `:8080`
`rosbridge_websocket`	`rosbridge_server`	PC	WebSocket bridge for the web client (`:9090`)
`nereo_controller_node`	`nereo_controller_node`	PC	PID / state-space controller (separate repo)
`rov_sim_node`	`gui_pkg`	PC	Local ROV simulator (no hardware needed)
`sonar_sim_node`	`sonar_pkg`	PC	Synthetic sonar data

Topics

Publisher	Topic	Type	Consumers
`imu_publisher`	`imu_data`	`sensor_msgs/Imu`	`gui_node`, `nereo_controller_node`
`imu_publisher`	`imu_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`bar_publisher`	`barometer_pressure`	`sensor_msgs/FluidPressure`	`gui_node`, `nereo_controller_node`
`bar_publisher`	`barometer_depth_salt`	`std_msgs/Float32`	`gui_node` (depth widget)
`bar_publisher`	`barometer_depth_fresh`	`std_msgs/Float32`	—
`bar_publisher`	`barometer_temperature`	`sensor_msgs/Temperature`	`gui_node`
`bar_publisher`	`barometer_diagnostic`	`diagnostic_msgs/DiagnosticArray`	—
`sonar_node` / `sonar_sim_node`	`sonar/distance`	`std_msgs/Float32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/confidence`	`std_msgs/Int32`	`gui_node`
`sonar_node` / `sonar_sim_node`	`sonar/profile`	`std_msgs/Float32MultiArray`	`gui_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_joy`	`nereo_interfaces/CommandVelocity`	`safety_node`
`joy_to_cmd_vel`	`/nereo_cmd_vel_no_fb`	`nereo_interfaces/CommandVelocity`	`nereo_controller_node`
`joy_to_cmd_vel`	`/joy_control_active`	`std_msgs/Bool`	`gui_node`, web
`joy_to_cmd_vel` / web	`/set_arm_mode`	`std_msgs/Bool`	ROV firmware
`nereo_controller_node`	`/nereo_cmd_vel` (controller mode)	`nereo_interfaces/CommandVelocity`	`safety_node`
`nereo_controller_node`	`/controller/setpoints`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/errors`	`std_msgs/Float64MultiArray`	tuner GUI
`nereo_controller_node`	`/controller/pid_terms`	`std_msgs/Float64MultiArray`	tuner GUI
web client	`/web_cmd_vel`	`nereo_interfaces/CommandVelocity`	`safety_node`
`safety_node`	`/nereo_cmd_vel` (direct mode)	`nereo_interfaces/CommandVelocity`	ROV firmware
ROV firmware	`/rov_armed`	`std_msgs/Bool`	`gui_node`, `joy_to_cmd_vel`, web
ROV firmware	`/thruster_status`	`nereo_interfaces/ThrusterStatuses`	—

Services

Service	Type	Provider	Used by	Effect
`barometer_reset_reference`	`std_srvs/Trigger`	`bar_publisher`	GUI "ZERO" button	Re-zeroes the surface pressure → `depth = 0` at current spot
`imu_reset_reference`	`std_srvs/Trigger`	`imu_publisher`	GUI "ZERO RPY" button	Stores current orientation as offset → `roll/pitch/yaw = 0` at current attitude

Safety arbitration (`safety_node`)

Condition	Output
Controller active (last msg < 0.5 s)	Controller command forwarded, web ignored
Only web active	Web command forwarded
Web silent 0–1 s	Last web command held
Web silent 1–1.5 s	Command ramped to zero
Web silent > 1.5 s	Zero command sent
No source active	Zero command sent

Architecture diagram

graph LR
subgraph RPI[rpi_ws — Raspberry Pi]
IMU[imu_publisher\nimu_reset_reference svc]
BAR[bar_publisher\nbarometer_reset_reference svc]
SONAR[sonar_node]
CAM[GStreamer cameras\nH264 UDP]
end
subgraph CTRL[gui_ws — Control Station]
GUI[gui_node\nROSQmlBridge / SonarBridge / ControllerBridge]
JOY[joy_to_cmd_vel]
SAFETY[safety_node]
WEB[web_server_node\nport 8080]
RB[rosbridge_websocket\nport 9090]
end
subgraph TUNE[ros2_controller_tuning_aid]
NCN[nereo_controller_node]
end
subgraph SIM[Simulators — local testing]
ROVSIM[rov_sim_node]
SONARSIM[sonar_sim_node]
end
PHONE[Phone / tablet\nbrowser]
IMU -.->|imu_data| GUI
IMU -.->|imu_data| NCN
BAR -.->|barometer_pressure| GUI
BAR -.->|barometer_pressure| NCN
BAR -.->|barometer_depth_salt| GUI
SONAR -.->|sonar/*| GUI
CAM -.->|RTP/UDP 5001-5003| GUI
JOY -->|nereo_cmd_vel_joy| SAFETY
JOY -->|nereo_cmd_vel_no_fb| NCN
NCN -->|nereo_cmd_vel| SAFETY
PHONE -->|web_cmd_vel via :9090| RB
RB --> SAFETY
WEB -->|UI :8080| PHONE
SAFETY -->|nereo_cmd_vel| ROV[(ROV firmware\nmicroROS)]
JOY -->|set_arm_mode| ROV
ROV -->|rov_armed| GUI
ROV -->|rov_armed| JOY
GUI -.->|set_parameters| NCN
NCN -.->|/controller/*| GUI

GUI features

Main dashboard

3× live H.264/UDP camera streams (main + 2 secondary)
IMU orientation widget (yaw / pitch / roll)
Depth, temperature, ROV arm/connection status
ZERO button → re-zeroes depth at the surface (calls barometer_reset_reference)
ZERO RPY button → re-zeroes attitude when the ROV is sitting level (calls imu_reset_reference)
Ctrl+Q → opens a popup with a QR code + URL (http://<ip>:8080) for the web controller. The IP is recomputed every time the shortcut is pressed, so it works even if you connect to Wi-Fi after launching the GUI.

Controller Tuner window (TUNER button)

Selects control mode (0 passthrough / 1 PID / 2 PID anti-windup / 3 CS)
Edits kp/ki/kd for depth/roll/pitch/yaw
Manual setpoint toggles per axis
Setpoint inputs in display units: depth in metres, roll/pitch/yaw in degrees. Conversion to controller units (Pa, rad) is done inside QML (density ρ = 1025 kg/m³, salt water — matches barometer_depth_salt). The controller-side parameters stay in their native units.
Full CS controller section (kx, ki, heave/angle limits)
Live telemetry: /controller/setpoints, /controller/errors, /controller/pid_terms

Sonar Viewer (SONAR button)

Waterfall + A-scan rendered into a QQuickImageProvider, confidence threshold filter.

Control Panel (CONTROL PANEL button)

Manual arming / mode toggles independent from the joystick.

Web controller (phone / tablet)

Open from any device on the same network:

Controller: http://<workstation-ip>:8080
ROV simulator: http://<workstation-ip>:8080/sim.html

The fastest way to get the URL on a phone: focus the GUI and press Ctrl+Q — a QR code with the URL appears.

The web client publishes on /web_cmd_vel. safety_node gives priority to the physical controller when both are active.

The web_server_node is robust to GUI shutdown: it installs a SIGTERM handler, closes the HTTP socket, and joins its serving thread on destroy_node(), so port 8080 is released cleanly and the launch file can be restarted without pkill.

Local testing (no ROV hardware)

# Terminal 1 — full ROV simulator (IMU, barometer, joystick, arm, 3 GStreamer test streams)
ros2 run gui_pkg rov_sim_node
# (without GStreamer: --ros-args -p simulate_cameras:=false)# Terminal 2 — sonar simulator
ros2 run sonar_pkg sonar_sim_node
# Terminal 3 — workstation stack
ros2 launch gui_pkg workstation.launch.py

Open http://localhost:8080 for the web controller and http://localhost:8080/sim.html for the top-down ROV simulator.

Manual test helpers

gui_ws/src/gui_pkg/test/cam_test.sh — three independent GStreamer test streams
ros2 run joystick_pkg rov_cmd_monitor — terminal dashboard of the live 6-DOF command vector

Unit tests

Inside unit_tests/ each subfolder is a CMake project for stdout-level debugging:

cd unit_tests/<name>
cmake .&& make
./<name>

Troubleshooting

Symptom	Cause	Fix
`Address already in use :8080` at relaunch	Old `web_server_node` still running	Should not happen anymore (the node releases the socket on SIGTERM); if it does, `pkill -f web_server_node`
GUI starts but no `nereo_controller_node`	`ros2_controller_tuning_aid` not built or not at sibling path	Check `~/Documents/PoliTOcean/RD/ros2_controller_tuning_aid/install/` exists
`imu_reset_reference service not available`	`rpi_ws` not rebuilt after the new service was added	On the Pi: `colcon build --packages-select nereo_sensors_pkg`
Ctrl+Q shows "Nessuna rete"	No default-route interface up	Connect to Wi-Fi / Ethernet, press Ctrl+Q again (re-evaluated each time)
Ctrl+Q shows "Pacchetto python3-qrcode mancante"	Missing system package	`sudo apt install python3-qrcode python3-pil`
Tuner setpoint value looks wrong after RELOAD	Controller still has old unit value	The GUI now converts deg↔rad and m↔Pa; if you set parameters from CLI in raw units, RELOAD will display them converted

Name		Name	Last commit message	Last commit date
SETUP_RPI		SETUP_RPI
gui_ws/src		gui_ws/src
rpi_ws/src		rpi_ws/src
unit_tests		unit_tests
.gitignore		.gitignore
.gitmodules		.gitmodules
LICENSE		LICENSE
README.md		README.md
autostart.sh		autostart.sh
connect_and_run.sh		connect_and_run.sh
gui_start.sh		gui_start.sh
rosdep.yaml		rosdep.yaml

Name		Name	Last commit message	Last commit date
SETUP_RPI		SETUP_RPI
gui_ws/src		gui_ws/src
rpi_ws/src		rpi_ws/src
unit_tests		unit_tests
.gitignore		.gitignore
.gitmodules		.gitmodules
LICENSE		LICENSE
README.md		README.md
autostart.sh		autostart.sh
connect_and_run.sh		connect_and_run.sh
gui_start.sh		gui_start.sh
rosdep.yaml		rosdep.yaml

Name		Name	Last commit message	Last commit date
SETUP_RPI		SETUP_RPI
gui_ws/src		gui_ws/src
rpi_ws/src		rpi_ws/src
unit_tests		unit_tests
.gitignore		.gitignore
.gitmodules		.gitmodules
LICENSE		LICENSE
README.md		README.md
autostart.sh		autostart.sh
connect_and_run.sh		connect_and_run.sh
gui_start.sh		gui_start.sh
rosdep.yaml		rosdep.yaml

Name		Name	Last commit message	Last commit date
SETUP_RPI		SETUP_RPI
gui_ws/src		gui_ws/src
rpi_ws/src		rpi_ws/src
unit_tests		unit_tests
.gitignore		.gitignore
.gitmodules		.gitmodules
LICENSE		LICENSE
README.md		README.md
autostart.sh		autostart.sh
connect_and_run.sh		connect_and_run.sh
gui_start.sh		gui_start.sh
rosdep.yaml		rosdep.yaml

Name		Name	Last commit message	Last commit date
SETUP_RPI		SETUP_RPI
gui_ws/src		gui_ws/src
rpi_ws/src		rpi_ws/src
unit_tests		unit_tests
.gitignore		.gitignore
.gitmodules		.gitmodules
LICENSE		LICENSE
README.md		README.md
autostart.sh		autostart.sh
connect_and_run.sh		connect_and_run.sh
gui_start.sh		gui_start.sh
rosdep.yaml		rosdep.yaml

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Nereo PoliTOcean

Table of contents

Installation

0. Clone the repos

1. System dependencies

2. PyQt6 with QML bindings (pip)

3. Register the custom rosdep sources

4. Install per-package dependencies

Build

Run

Launch arguments

Physical controller mapping

Workspace structure

ROS 2 node and topic map

Nodes

Topics

Services

Safety arbitration (safety_node)

Architecture diagram

GUI features

Main dashboard

Controller Tuner window (TUNER button)

Sonar Viewer (SONAR button)

Control Panel (CONTROL PANEL button)

Web controller (phone / tablet)

Local testing (no ROV hardware)

Manual test helpers

Unit tests

Troubleshooting

About

Resources

Stars

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Forks

Releases

Packages

Used by

Contributors

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Latest commit

History

Folders and files

Repository files navigation

Nereo PoliTOcean

Table of contents

Installation

0. Clone the repos

1. System dependencies

2. PyQt6 with QML bindings (pip)

3. Register the custom rosdep sources

4. Install per-package dependencies

Build

Run

Launch arguments

Physical controller mapping

Workspace structure

ROS 2 node and topic map

Nodes

Topics

Services

Safety arbitration (safety_node)

Architecture diagram

GUI features

Main dashboard

Controller Tuner window (TUNER button)

Sonar Viewer (SONAR button)

Control Panel (CONTROL PANEL button)

Web controller (phone / tablet)

Local testing (no ROV hardware)

Manual test helpers

Unit tests

Troubleshooting

About

Resources

Safety arbitration (`safety_node`)

Safety arbitration (`safety_node`)

Safety arbitration (`safety_node`)