robot-bringup

# Robot Bringup Skill

## When to Use This Skill

- Configuring a robot to automatically start its full ROS2 stack on boot via systemd
- Writing systemd unit files that correctly source ROS2 workspaces and set DDS environment
- Composing layered launch files (hardware, drivers, perception, application) into a single bringup
- Setting up ordered startup with health checks to avoid race conditions between dependent nodes
- Writing udev rules for deterministic device naming of cameras, LiDARs, and serial devices
- Configuring CycloneDDS or FastDDS for multi-machine ROS2 discovery across robot and base station
- Implementing watchdog and heartbeat monitoring for production robot systems
- Setting up log rotation and structured logging for long-running robot deployments
- Writing graceful shutdown handlers that bring actuators to a safe state before exit
- Debugging boot-time failures, service ordering issues, or device enumeration races

## The Robot Bringup Stack

A production robot bringup follows a layered startup sequence from hardware initialization through application-level nodes. Each layer depends on the one below it.

```
┌─────────────────────────────────────────────────────────────────────┐
│                        APPLICATION LAYER                            │
│  Navigation, manipulation, mission planning, HRI                    │
├─────────────────────────────────────────────────────────────────────┤
│                        PERCEPTION LAYER                             │
│  Object detection, SLAM, point cloud filtering, sensor fusion       │
├─────────────────────────────────────────────────────────────────────┤
│                         DRIVER LAYER                                │
│  Camera drivers, LiDAR drivers, motor controllers, IMU              │
├─────────────────────────────────────────────────────────────────────┤
│                        HARDWARE LAYER                               │
│  udev rules, device enumeration, USB reset, firmware check          │
├─────────────────────────────────────────────────────────────────────┤
│                      ROS2 ENVIRONMENT                               │
│  Source workspace, set RMW, ROS_DOMAIN_ID, DDS config               │
├─────────────────────────────────────────────────────────────────────┤
│                    SYSTEMD TARGETS & SERVICES                       │
│  network-online.target → robot-hw.target → robot-bringup.target     │
├─────────────────────────────────────────────────────────────────────┤
│                      LINUX BOOT (systemd)                           │
│  BIOS/UEFI → GRUB → kernel → systemd init                          │
├─────────────────────────────────────────────────────────────────────┤
│                         HARDWARE BOOT                               │
│  Power supply, onboard computer, peripherals                        │
└─────────────────────────────────────────────────────────────────────┘
```

## systemd Service Units for ROS2

### Basic ROS2 Service Unit

Place service files in `/etc/systemd/system/`. This template starts a ROS2 launch file as a long-running service with watchdog support.

```ini
# /etc/systemd/system/robot-bringup.service
[Unit]
Description=Robot ROS2 Bringup Stack
Documentation=https://github.com/my-org/my-robot
After=network-online.target robot-hw.target
Wants=network-online.target
Requires=robot-hw.target

[Service]
Type=notify
User=robot
Group=robot
WorkingDirectory=/home/robot

# Load ROS2 environment variables from a dedicated env file
EnvironmentFile=/etc/robot/ros2.env

# Pre-start check: verify critical devices exist
ExecStartPre=/usr/local/bin/robot-device-check.sh

# Start the ROS2 launch file via bash so we can source the workspace
ExecStart=/bin/bash -c '\
  source /opt/ros/${ROS_DISTRO}/setup.bash && \
  source /home/robot/ros2_ws/install/setup.bash && \
  exec ros2 launch my_robot_bringup bringup.launch.py'

# Graceful shutdown: send SIGINT first (Ctrl+C equivalent for ROS2)
ExecStop=/bin/kill -INT $MAINPID
TimeoutStopSec=30

# Restart on failure, but not on clean exit
Restart=on-failure
RestartSec=5

# systemd watchdog: service must call sd_notify(WATCHDOG=1) within this interval
WatchdogSec=30

# Process management
KillMode=mixed
KillSignal=SIGINT
FinalKillSignal=SIGKILL
TimeoutStartSec=60

# Logging
StandardOutput=journal
StandardError=journal
SyslogIdentifier=robot-bringup

[Install]
WantedBy=multi-user.target
```

### Environment Setup in systemd

Store environment variables in a dedicated file rather than sourcing .bashrc (which is not loaded by systemd).

```bash
# /etc/robot/ros2.env
# ROS2 distribution
ROS_DISTRO=humble

# DDS middleware selection
RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

# Domain isolation: unique per robot to avoid cross-talk
ROS_DOMAIN_ID=42

# CycloneDDS configuration file path
CYCLONEDDS_URI=file:///etc/robot/cyclonedds.xml

# Disable localhost-only mode for multi-machine setups
ROS_LOCALHOST_ONLY=0

# Logging configuration
ROS_LOG_DIR=/var/log/ros2
RCUTILS_LOGGING_USE_STDOUT=0
RCUTILS_COLORIZED_OUTPUT=0

# Robot-specific configuration
ROBOT_NAME=my_robot_01
ROBOT_CONFIG_DIR=/etc/robot/config
```

### Dependencies Between Services

Split the robot stack into multiple systemd services with explicit ordering. This allows independent restart of layers and clearer failure isolation.

```ini
# /etc/systemd/system/robot-drivers.service
[Unit]
Description=Robot Hardware Drivers (cameras, LiDAR, IMU, motors)
After=network-online.target robot-hw.target
Wants=network-online.target
Requires=robot-hw.target

[Service]
Type=notify
User=robot
EnvironmentFile=/etc/robot/ros2.env
ExecStart=/bin/bash -c '\
  source /opt/ros/${ROS_DISTRO}/setup.bash && \
  source /home/robot/ros2_ws/install/setup.bash && \
  exec ros2 launch my_robot_bringup drivers.launch.py'
Restart=on-failure
RestartSec=5
WatchdogSec=30
KillMode=mixed
KillSignal=SIGINT
TimeoutStopSec=20
StandardOutput=journal
SyslogIdentifier=robot-drivers

[Install]
WantedBy=robot-bringu