flowchart TD

    A(Warthog Rosbridge Server) -->|Warthog Diagnostics| B(Steward OS)
    B -->|Movement Commands| A
    B --> |Diagnostics & Sensor Data|C(Canopy Rosbridge Client)
    C --> |User Commands|B
    B --> |Movement Commands|D(EcoSim KISS Client)
    D --> |Sensor Data|B

Bridges

Nodes within Steward OS communicate internally using ROS2 (Fast DDS protocol). However, Steward uses three significant subsystems that do not run ROS2:

1. Our Clearpath Warthog base, which runs ROS1
2. Our simulator, EcoSim
3. Our web interface, Canopy

KISS Bridge

The Keep It Simple, Stupid (KISS) bridge is a minimal, WebSocket-based bridge that we’ve designed to transfer large data payloads quickly. Specifically, we use KISS to send image streams and point clouds from EcoSim to Steward OS. We initially implemented a rosbridge client in C#, but Unity’s JSON serialization tools ended up being far too slow.

Rosbridge

Steward OS communicates both with the Warthog base and Canopy using Rosbridge, a standardized WebSocket protocol.

The Warthog hosts a Rosbridge server, which Steward OS connects to as a client.

Steward OS hosts its own Rosbridge server, which Canopy connects to as a client.

Steward OS combines its client (for connecting to the Warthog) and its server (for connecting to Canopy) in its web_bridge package.