New packages:
saltybot_fleet_msgs — 4 msgs (RobotInfo, MapChunk, Frontier, FrontierArray)
+ 2 srvs (RegisterRobot, RequestFrontier)
saltybot_fleet — 4 nodes + 2 launch files + config + CLI tool
Nodes:
map_broadcaster_node — zlib-compress local OccupancyGrid → /fleet/maps @ 1Hz
+ /fleet/robots heartbeat with battery/status
fleet_manager_node — robot registry, MapMerger (multi-grid SE2-aligned merge),
frontier aggregation, /fleet/request_frontier service,
heartbeat timeout + stale frontier re-assignment
frontier_detector_node — scipy label-based frontier detection on merged map
→ /fleet/exploration_frontiers_raw
fleet_explorer_node — Nav2 NavigateToPose cooperative exploration state machine:
IDLE→request→NAVIGATING→ARRIVED→IDLE + STALLED backoff
Supporting modules:
map_compressor.py — binary serialise + zlib OccupancyGrid encode/decode
map_merger.py — SE(2)-transform-aware multi-grid merge with conservative
obstacle inflation (occupied beats free on conflict)
frontier_detector.py — numpy frontier mask + scipy connected-components + scoring
landmark_aligner.py — ArUco-landmark SE(2) estimation (Horn 2D least-squares)
to align robot map frames into common fleet_map frame
Topic layout:
/fleet/maps MapChunk per-robot compressed grids
/fleet/robots RobotInfo heartbeats + status
/fleet/merged_map OccupancyGrid coordinator merged output
/fleet/exploration_frontiers FrontierArray consolidated frontiers
/fleet/status String (JSON) coordinator health
/<robot_ns>/rtabmap/map input per robot
/<robot_ns>/rtabmap/odom input per robot
/<robot_ns>/navigate_to_pose Nav2 action per robot
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Jetson Nano — AI/SLAM Platform Setup
Self-balancing robot: Jetson Nano dev environment for ROS2 Humble + SLAM stack.
Stack
| Component | Version / Part |
|---|---|
| Platform | Jetson Nano 4GB |
| JetPack | 4.6 (L4T R32.6.1, CUDA 10.2) |
| ROS2 | Humble Hawksbill |
| DDS | CycloneDDS |
| SLAM | slam_toolbox |
| Nav | Nav2 |
| Depth camera | Intel RealSense D435i |
| LiDAR | RPLIDAR A1M8 |
| MCU bridge | STM32F722 (USB CDC @ 921600) |
Quick Start
# 1. Host setup (once, on fresh JetPack 4.6)
sudo bash scripts/setup-jetson.sh
# 2. Build Docker image
bash scripts/build-and-run.sh build
# 3. Start full stack
bash scripts/build-and-run.sh up
# 4. Open ROS2 shell
bash scripts/build-and-run.sh shell
Docs
docs/pinout.md— GPIO/I2C/UART pinout for all peripheralsdocs/power-budget.md— 10W power envelope analysis
Files
jetson/
├── Dockerfile # L4T base + ROS2 Humble + SLAM packages
├── docker-compose.yml # Multi-service stack (ROS2, RPLIDAR, D435i, STM32)
├── README.md # This file
├── docs/
│ ├── pinout.md # GPIO/I2C/UART pinout reference
│ └── power-budget.md # Power budget analysis (10W envelope)
└── scripts/
├── entrypoint.sh # Docker container entrypoint
├── setup-jetson.sh # Host setup (udev, Docker, nvpmodel)
└── build-and-run.sh # Build/run helper
Power Budget (Summary)
| Scenario | Total |
|---|---|
| Idle | 2.9W |
| Nominal (SLAM active) | ~10.2W |
| Peak | 15.4W |
Target: 10W (MAXN nvpmodel). Use RPLIDAR standby + 640p D435i for compliance.
See docs/power-budget.md for full analysis.