Enable 2D lidar SLAM - Qualcomm Dragonwing Documentation

Pipeline flow for 2D lidar SLAM

The following figure shows the pipeline flow for 2D lidar simultaneous localization and mapping (SLAM):

The following table describes the ROS nodes used in the 2D lidar SLAM pipeline.

Node name	Function
`cartographer_node`	Receives `/scan` and `/odom` topics, runs mapping, localization, and saves the map or queries the relocation status. The node is based on the ROS service `qrb_slam_command`.
`cartographer_occupancy_grid_node`	Receives map-related topics sent by the `cartographer_node` and publishes a ROS standard map (`/map`).

The following table describes the ROS topics used in the 2D lidar SLAM pipeline.

ROS topic	Type	Description
`/scan`	`sensor_msgs.msg.LaserScan`	Receives lidar scan data.
`/odom`	`nav_msgs.msg.Odometry2`	Receives odometry data.
`/tracked_pose`	`geometry_msgs.msg.PoseStamped`	Publishes the current tracked robot pose.
`/scan_matched_points2`	`sensor_msgs.msg.PointCloud2`	Publishes scan-matched point cloud for debugging and visualization.
`/tf`	`tf2_msgs.msg.TFMessage`	Publishes coordinate transform information for multi-frame conversions.
`/submap_list`	`cartographer_ros_msgs.msg.SubmapList`	Publishes submap list for map stitching and visualization.
`/map`	`nav_msgs.msg.OccupancyGrid`	Publishes the occupancy grid map.

The following table describes the ROS services used in the 2D lidar SLAM pipeline.

ROS service	Type	Description
`/qrb_slam_command`	`qrb_ros_slam_msgs.srv.SlamCommand`	Provides SLAM control services, such as start, stop, and save map. See qrb_ros_slam_msgs on GitHub.

You have set up the device, installed ROS2 Jazzy and the Qualcomm Intelligent Robotics (QIR) SDK on the device according to Install the QIR SDK.

Install the 2D lidar SLAM packages

sudo apt install ros-jazzy-qcom-cartographer ros-jazzy-qrb-ros-slam-msgs ros-jazzy-qcom-cartographer-ros

Set up the robot base

If you have a Qualcomm’s robot base, set it up.
If you are using a custom or third-party robot base, apply configurations appropriate to your own robot base. Ensure the robot base can publish odometry data of the type nav_msgs.msg.Odometry2 on the topic /odom.

Set up the 2D lidar

source /opt/ros/jazzy/setup.bash export ROS_DOMAIN_ID=124
ros2 launch rplidar_ros rplidar_a3_launch.py

Run the 2D lidar SLAM

source /opt/ros/jazzy/setup.bash
export ROS_DOMAIN_ID=124
ros2 launch cartographer_ros qrb_2d_lidar_slam.launch.py

Run the qrb_slam_service_request script

#Env set up
source /opt/ros/jazzy/setup.bash
export ROS_DOMAIN_ID=124
sh /opt/ros/jazzy/share/cartographer_ros/scripts/qrb_slam_service_request.sh