🚀 Launch Files and System Bringup
See the source code for implementation details.
The launch files in your project are the blueprint for starting all necessary ROS2 nodes in the correct order with the correct configuration.
This ensures the robot, perception, navigation, and manipulation subsystems are fully operational with a single command.
🏗 Launch File Architecture
Your main entry point is:
full_system.launch.py
This launch file:
- Starts drivers (LIMO base, Orbbec depth camera, LiDAR)
- Starts SLAM or localization
- Launches Navigation (Nav2)
- Runs Object Detection Node (YOLOv8)
- Starts Mission Manager
- Brings up Pick & Drop Nodes
- Launches Pose Setter
🔄 System Bringup Logic
Startup Sequence (simplified):
- Drivers
- Bring up robot base hardware
- Initialize sensors (LiDAR, camera)
- SLAM / Localization
- If mapping: start Cartographer/RTAB-Map
- If localizing: start AMCL with saved map
- Navigation Stack
- Starts Nav2 servers (controller, planner, behavior tree)
- Perception
- Launch object detector, subscribing to camera topics
- Coordination
- Launch mission manager to handle state machine
- Manipulation
- Launch pick/drop nodes and pose setter
Always check that drivers and sensors are running before bringing up perception and navigation.
⚙️ Parameter Configuration
Launch files can load .yaml parameter files to configure:
- Navigation tuning (in
nav2_params.yaml) - SLAM settings
- YOLO detector thresholds
- Arm/gripper control parameters
- Base pose in Pose Setter
Example parameter load in a launch file:
params_file = PathJoinSubstitution(
[FindPackageShare('my_robot_bringup'), 'config', 'nav2_params.yaml']
)
Node(
package='nav2_bringup',
executable='bringup_launch.py',
parameters=[params_file]
)
🛠 Debugging Launch Issues
Common checks:
-
Is the workspace sourced?
source install/setup.bash -
Are topics active?
ros2 topic list -
Check launch output logs for missing dependencies or parameter errors.
-
Run subsystems individually to isolate failures:
ros2 launch limo_bringup limo_start.launch.py
ros2 launch object_detector detector.launch.py
Don't mix Foxy and Humble packages — they may cause runtime errors.
🛠 Creating a Custom Launch File
If you want to modify the system bringup (e.g., skip mapping and go directly to localization):
1. Create new launch file in launch/ directory:
from launch import LaunchDescription
from launch_ros.actions import Node
def generate_launch_description():
return LaunchDescription([
Node(package='pose_setter', executable='pose_setter_node'),
Node(package='nav2_bringup', executable='bringup_launch.py'),
Node(package='object_detector', executable='detector_node'),
# Add/remove components as needed
])
2. Make it executable:
chmod +x my_custom_launch.py
3. Run it:
ros2 launch my_package my_custom_launch.py