AUSRA: Autonomous Unified Swarm Robotics Architecture

This repository contains the complete ROS 2 multi-robot communication, navigation, and map-merging stack for the AUSRA swarm system.

The system is designed with a hybrid high-level/low-level architecture. Each robot (e.g., Jetson Orin Nano) runs ROS 2 Humble for SLAM and local navigation, while an ESP32-S3 runs micro-ROS for real-time motor control and hardware interfacing.

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📡 Network & Communication Layer (DDS + Zenoh)

To handle challenging, bandwidth-constrained wireless environments in swarm robotics, the communication layer uses a hybrid DDS + Zenoh architecture:

• Local DDS Isolation: Each robot and the base station runs ROS 2 with ROS_LOCALHOST_ONLY=1. High-bandwidth internal topics (like raw /scan, /odom, and /tf trees) are restricted to local loopback to avoid flooding the WiFi network.
• Zenoh Bridging: A zenoh-bridge-ros2dds daemon runs on each Jetson and the laptop to tunnel only allowlisted, low-bandwidth topics across the WiFi network.
• Map Compression: A custom Python relay node compresses occupancy grids using zlib (enable_compression:=true), reducing transmitted map sizes from ~1MB down to ~1KB (a >99% reduction).
• Domain Segregation: Swarm communication is bound to ROS_DOMAIN_ID=0.
• Zero-Configuration Time Sync: Because Zenoh is highly sensitive to clock skew, a custom time synchronization script (sync_time.sh) is used to sync Jetson clocks to the laptop's clock before every session (since the Jetsons lack RTC battery backups).

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📁 Repository Structure

AUSRA-Autonomous-System-hardware_with_nav2/
├── ausra_comms/               # [Jetson] Throttles/compresses maps, publishes heartbeat
│   └── launch/
│       ├── hardware_with_comms.launch.py   # Main robot launch (SLAM + Hardware + Comms)
│       └── decentralized_robot.launch.py   # Launch configuration for decentralized swarm nodes
├── ausra_comms_base/          # [Laptop] Map merge, decompressor, RViz, scripts, docs
│   ├── launch/
│   │   ├── base_station.launch.py          # Full laptop stack launch (merger + decompressor)
│   │   └── map_merge.launch.py             # Canvas expansion and merge node
│   ├── scripts/
│   │   └── start_base.sh                   # Wrapper script (ping check + base launch)
│   └── docs/                               # Detailed design & setup documentation
│       ├── DEPLOYMENT_2JETSONS.md          # 2-Jetson + Laptop step-by-step runbook
│       ├── DEPLOYMENT_DECENTRALIZED.md     # Decentrailzed map merging guides
│       ├── SYSTEM_ARCHITECTURE.md          # Swarm data flows and namespaces
│       ├── COMMUNICATION_ARCHITECTURE.md   # Hybrid comms approach & network design
│       └── FUTURE_WORK.md                  # Roadmap for decentralized merging
├── ausra_map_merge_HW/        # [Laptop] Stamps local maps onto fixed-size canvases
├── m-explore-ros2/            # [Laptop] Multi-robot map merging engine (m-explore)
├── docs/                      # Global documentation folder
│   └── TIME_SYNC_GUIDE.md     # Setup and operational guide for clock synchronization
└── HARDWARE_NAVIGATION_SETUP.md # Original hardware/navigation guide

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🚀 Quick Start Guide

1. Sync Jetson Clocks (Per-Session Ritual)

Since Jetson Orin Nanos have no RTC battery, you must sync their clocks to the laptop's time before launching ROS/Zenoh:

# On the laptop
cd ~
./sync_time.sh

For the one-time sudoers configuration setup, refer to Time Sync Guide.

2. Run on the Robots (Jetsons)

SSH into each Jetson, source your workspace, and launch the decentralized robot stack:

# Terminal on Jetson 1 (ausra_1)
export ROS_DOMAIN_ID=0
export ROS_LOCALHOST_ONLY=1
ros2 launch ausra_comms decentralized_robot.launch.py robot_name:=ausra_1 robot_config:="ausra_1:0.0:0.0 ausra_2:0.0:1.2"

# Terminal on Jetson 2 (ausra_2)
export ROS_DOMAIN_ID=0
export ROS_LOCALHOST_ONLY=1
ros2 launch ausra_comms decentralized_robot.launch.py robot_name:=ausra_2 robot_config:="ausra_1:0.0:0.0 ausra_2:0.0:1.2"

3. Run on the Base Station (Laptop)

Ensure you are connected to the same WiFi network, source your workspace, and launch the base station using the automated script:

cd ~/ausra_ws/src/AUSRA-Autonomous-System-hardware_with_nav2/ausra_comms_base/scripts
./start_base.sh robot_config:="ausra_1:0.0:0.0 ausra_2:0.0:1.2"

Or launch directly:

export ROS_DOMAIN_ID=0
export ROS_LOCALHOST_ONLY=1
ros2 launch ausra_comms_base base_station.launch.py

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🛠️ Detailed Documentation

Deep-dive documentation is located in the docs/ and ausra_comms_base/docs/ directories:

• 📖 Time Sync Guide (Jetson Clocks without Internet)
• 📖 Zenoh Integration Guide (Transport Setup)
• 📖 Step-by-step Deployment Guide (2 Jetsons + Laptop)
• 📖 Decentralized Deployment Guide
• 📖 System Architecture & Namespace Data Flows
• 📖 Communication Architecture & Network Tuning
• 📖 Swarm Roadmap & Decentralized Merging Plan

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💻 Sharing via GitHub

To upload this workspace to GitHub so your team can access it:

1. Create a new repository on GitHub named ausra_comms.
2. Run the following commands in the root of this repository to link and push:

   # Add your GitHub remote origin
   git remote add origin https://github.com/Elmala7/ausra_comms.git
   
   # Push files to main branch
   git push -u origin main