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Execute the Wandering Application on the Jackal™ Robot

This tutorial details the steps to install and run the Wandering Application with Intel® RealSense™ camera input on a Clearpath Robotics Jackal™ robot. The Wandering Application will use the Nav2 navigation stack and the RTAB-Map SLAM application to let the Jackal™ robot move around and create a map of the environment.

Prerequisites

Installation and Execution

Make sure that you have set up your Jackal™ robot as described on the ./jackal-intel-robotics-sdk{.interpreted-text role="doc"} page. In addition, you can run the steps on page ./jackal-keyboard-teleop{.interpreted-text role="doc"} in order to verify that your ROS 2 installation can communicate with the Motor Control Unit (MCU).

To install the Deb package of the Wandering tutorial on Jackal™ robots, run the following command:

sudo apt update
sudo apt install ros-humble-wandering-jackal-tutorial

Make sure that you are logged in as the administrator user. Run the following script, which will start the Wandering Application. After a few seconds, the Jackal™ robot will start moving and the RTAB-Map SLAM application will create the map.

/opt/ros/humble/share/wandering_jackal_tutorial/scripts/wandering_jackal.sh

Wandering Application running on the Jackal™ robot: the rviz2 tool shows the robot with the identified map and the image of the Intel® RealSense™ camera.

Figure: Wandering Application running on the Jackal™ robot. The rviz2 tool shows the robot with the identified map and the image of the Intel® RealSense™ camera.

Jackal™-Specific Adaptations

The shell script and the launch file of the Wandering tutorial have been adapted to the ecosystem of the Jackal™ robot. In particular, they include several remapping definitions, which align the camera and IMU related topics with the topic names expected by the nodes of the Wandering tutorial.

You don't have to read the following subsections if you just want to run the tutorial. But they might provide relevant background information if you want to adapt the tutorial to a robot with a different ecosystem.

Adaptation of the Camera Namespace

As mentioned on the ./jackal-intel-robotics-sdk{.interpreted-text role="doc"} page, the names of the camera-related topics depend on the version of the installed ros-humble-realsense2-camera package. The camera-related topics start with:

  • /sensors/camera_0/camera/ if the ros-humble-realsense2-camera package is version 4.55
  • /sensors/camera_0/ if the ros-humble-realsense2-camera package is version 4.54

In order to support both versions of the ros-humble-realsense2-camera package, the shell script /opt/ros/humble/share/wandering_jackal_tutorial/scripts/wandering_jackal.sh checks the name of the camera-related topics and assigns the variable ${CAMERA_NAMESPACE} according to the identified camera namespace.

Adaptation of the depthimage_to_laserscan Node

This node converts the depth image of the Intel® RealSense™ camera into a 2D laser scan. The node expects that it can subscribe to the topics depth and depth_camera_info. This requirement is fulfilled by remapping the following topics, which are published by the camera node of the Jackal™ robot:

  • if ros-humble-realsense2-camera version is 4.55:
Topic name expected by the node True topic name on the Jackal robot
depth /sensors/camera_0/camera/depth/image_rect_raw
depth_camera_info /sensors/camera_0/camera/depth/camera_info
  • if ros-humble-realsense2-camera version is 4.54:
Topic name expected by the node True topic name on the Jackal robot
depth /sensors/camera_0/depth/image_rect_raw
depth_camera_info /sensors/camera_0/depth/camera_info

The script /opt/ros/humble/share/wandering_jackal_tutorial/scripts/wandering_jackal.sh considers the necessary remapping of both topics when it starts the depthimage_to_laserscan node:

ros2 run depthimage_to_laserscan depthimage_to_laserscan_node --ros-args \
         --remap depth:=${CAMERA_NAMESPACE}/depth/image_rect_raw \
         --remap depth_camera_info:=${CAMERA_NAMESPACE}/depth/camera_info \
         -p scan_time:=0.033 -p range_min:=0.1 -p range_max:=2.5 \
         -p output_frame:=camera_0_depth_frame &

The depthimage_to_laserscan node publishes the topic /scan, which is subscribed by several other nodes. The laser scan messages, which are broadcast via this topic, must include a frame id. This frame id, whose default value is camera_depth_frame, must be adapted to the actual link name on the robot. According to the TF2 tree of the Jackal™ robot, which is shown on the ./jackal-intel-robotics-sdk{.interpreted-text role="doc"} page, the actual link name is camera_0_depth_frame.

The above ros2 run command specifies the appropriate output frame id when it starts the depthimage_to_laserscan node. This is achieved by means of the parameter output_frame:=camera_0_depth_frame.

Adaptation of the imu_filter_madgwick Node

This filter node fuses angular velocities and accelerations from the robot's IMU device into an orientation. The node expects that it can subscribe to the topic /imu/data_raw. The topic /imu/data_raw is a remapped representation of the topic /sensors/imu_0/data_raw, which is published by the jackal_mcu node of the Jackal™ robot:

Topic name expected by the node True topic name on the Jackal™ robot
/imu/data_raw /sensors/imu_0/data_raw

The script /opt/ros/humble/share/wandering_jackal_tutorial/scripts/wandering_jackal.sh considers the necessary remapping when it starts the imu_filter_madgwick node:

ros2 run imu_filter_madgwick imu_filter_madgwick_node --ros-args \
         -p remove_gravity_vector:=true -p use_mag:=false -p publish_tf:=false \
         --remap /imu/data_raw:=/sensors/imu_0/data_raw &

Adaptation of the rgbd_sync Node

This node synchronizes RGB, depth and camera_info messages into a single message. The node expects that it can subscribe to the topics rgb/image, rgb/camera_info, and depth/image. This requirement is fulfilled by remapping the following topics, which are published by the camera node of the Jackal™ robot:

  • if ros-humble-realsense2-camera version is 4.55:

    Topic name expected by the node True topic name on the Jackal™ robot
    rgb/image /sensors/camera_0/camera/color/image_raw
    rgb/camera_info /sensors/camera_0/camera/color/camera_info
    depth/image /sensors/camera_0/camera/aligned_depth_to_color/image_raw

  • if ros-humble-realsense2-camera version is 4.54:

    Topic name expected by the node True topic name on the Jackal™ robot
    rgb/image /sensors/camera_0/color/image_raw
    rgb/camera_info /sensors/camera_0/color/camera_info
    depth/image /sensors/camera_0/aligned_depth_to_color/image_raw

The node publishes the topic rgbd_image, which is remapped to

  • /sensors/camera_0/camera/rgbd_image if the ros-humble-realsense2-camera package is version 4.55,
  • /sensors/camera_0/rgbd_image if the ros-humble-realsense2-camera package is version 4.54.

The definition of the remapping can be found in the launch files rtabmap_jackal.launch.py and rtabmap_jackal.rs454.launch.py. Both launch files can be found in the folder /opt/ros/humble/share/wandering_jackal_tutorial/launch/.

Adaptation of the rtabmap Node

This node implements the RTAB-Map SLAM approach. The node expects that it can subscribe to the topic rgbd_image. The topic rgbd_image is a remapped representation of the topic

  • /sensors/camera_0/camera/rgbd_image if the ros-humble-realsense2-camera package is version 4.55,
  • /sensors/camera_0/rgbd_image if the ros-humble-realsense2-camera package is version 4.54,

which is published by the rgbd_sync node.

The definition of the remapping can be found in the launch files rtabmap_jackal.launch.py and rtabmap_jackal.rs454.launch.py. Both launch files can be found in the folder /opt/ros/humble/share/wandering_jackal_tutorial/launch/.