sl-controls 173b538f44 feat(controls): Priority-based cmd_vel multiplexer (Issue #228)
Implement priority-based velocity command routing with timeout-based fallback:
- Teleop (priority 1) > Nav2 (priority 2) > Docking (priority 3)
- 0.5s timeout per source: inactive sources are skipped in priority selection
- When no source is active, publish zero command for safety

Features:
- 50Hz multiplexing frequency with configurable parameters
- JSON status publishing (/saltybot/cmd_vel_mux_status) for telemetry
- Automatic priority escalation: teleop preempts nav2, nav2 preempts docking
- Fallback chain: if teleop times out, nav2 takes over; if nav2 times out, docking active
- Zero command safety: all sources timeout = immediate motor stop

Test Coverage:
- 20+ unit tests covering enum, initialization, subscriptions
- Priority selection logic (teleop preemption, nav2 preemption)
- Timeout detection and source fallback
- Realistic scenario tests (teleop release, priority escalation chains)
- JSON status format validation

Config: frequency=50Hz, source_timeout=0.5s

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
2026-03-02 12:01:00 -05:00
..

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

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.