Intro

Topics

• /nekton/pressure: Returns the result from the pressure sensor in Pascals

  • Type: sensor_msgs/msg/FluidPressure:

• /nekton/imu: Returns the result from the IMU, including a quaternion for orientation and 3D vectors for linear and angular acceleration

  • Type: sensor_msgs/msg/Imu

• /nekton/thrusters/id_<thruster_number>/input: Controls the power of the thruster; using a 0–100 range for now

  • Type: uv_gazebo_ros_plugins_msgs/msg/FloatStamped

• /nekton/sonar_forward: Contains 3D points (same height) where the sonar received returns

  • Type: Changed from sensor_msgs/msg/PointCloud2 to LaserScan

• /nekton/camera_forward/camera_info

• /nekton/camera_forward/image_raw

• /data: generated or fused data not coming directly from sensors (e.g., estimated position from sensor fusion or post-processed camera output)

Setup

• Create workspace and clone repo into src

mkdir ~/vip_ws/src && cd ~/vip_ws/src

• Install any missing system-level dependencies if needed

# Initialize rosdep if not done
sudo rosdep init
rosdep update
 
# Install all dependencies for the workspace
rosdep install --from-paths src --ignore-src -r -y

• Build project

cd ~/vip_ws
colcon build --symlink-install
source install/setup.bash

Simulation

Full Underwater Simulation

Gazebo runs in the background, using the GPU? for physics simulation. The full underwater simulation utilizes the hydrodynamics-plugin

test.launch

<!--This file will launch the full nekton software suite for testing topside and onboard -->
<launch>
    <!-- might be better to have the topside/onboard launch files add their own groups instead -->
    <group>
        <push-ros-namespace namespace="topside"/>
        <include file="$(find-pkg-share topside_bringup)/launch/topside.launch"/>
    </group>
 
    <group>
        <include file="$(find-pkg-share nekton_bringup)/launch/odom_simulation.py"/>
    </group>
</launch>

test.launch
   ├── topside.launch (UI / control)
   └── odom_simulation.py
          ├── Gazebo launch
          ├── world:=underwater.world (default)
          └── robot + sensors + controllers

• Run full underwater simulation (with hydrodynamics enabled)

ros2 launch nekton_bringup test.launch

Lightweight sensor simulation

sensor.world provides a flat ground-plane simulation (easier to add obstacles), designed for lightweight testing by excluding hydrodynamics and other computationally expensive physics effects.

• Run sensor test simulation using sensor.world

ros2 launch nekton_bringup odom_simulation.py world:=sensor.world

Bash aliases

• Define aliases in ~/.bashrc (or added by the Docker setup)

alias src='cd ~/vip_ws; source ./install/setup.bash';
alias build='cd ~/vip_ws; colcon build; src;'
alias launch='src; ros2 launch nekton_bringup test.launch';

• Usage

launch

• Or

launch world:=sensor.world

• List valid worlds (should show sensor.world and underwater.world)

find ~/vip_ws -iname "*.world"

Rviz

• Visualize in RViz

rviz2 nekton.rviz

GUI

The current plan is to recreate similar functionality to the previous icefin software:

Nekton UI

• Artificial Horizon
• Buttons
• Alerts
• Camera feed
• Sonar feed
• Depth and altimeter visualization
• Thruster visualization
• Camera and Sonar Mosaicing

• Icefin GUI
• Nekton GUI
• Nekton React GUI