ROS - Connect /map topic with Isaac Sim Environment

[asibarra98]

Hello,

I am having an issue where I have a /map topic and its showing on my “rostopic list” command but it is not connected to my Isaac Sim environment. I published a PoseTree which has no parent prim so that it is set to “world” by default. I then add my robot’s links to the target prims. However, I have uploaded a map to my roslaunch file so that I can see it in rviz, but it is not connecting to my world environment. I am pretty much creating a Navigation Stack program for a custom autonomous robot. This is what it looks like for the ROS frame map (without static transforms):

I have tried another idea where I publish static transforms from the /map topic to the world and /odom but its splits the graph in two (with static transforms):

I would like to know if I am setting my PoseTree incorrectly or there is something I am not seeing that I have to set up in Isaac Sim. An example of my PoseTree is located below:

and my a_star.launch file is located below:

<?xml version="1.0" encoding="UTF-8"?>
<!-- High level launch file for Unit 3 A-Star exercise solution  -->
<!-- Requires simulation w/robot running -->
<launch>
  <arg name="model" default="$(find jeep_model)/urdf/jeep_updated_official.urdf"/>
  <arg name="gui" default="true" />

  <param name="robot_description" command="$(find xacro)/xacro --inorder $(arg model)" />
  <param name="use_gui" value="$(arg gui)"/>

  <!-- Run the map server to load a pre-made map -->
  <arg name="map_file" default="$(find jeep_nav)/maps/UTSA_ENV_DRAFT/utsa_NE.yaml"/>
  <node name="map_server" pkg="map_server" type="map_server" args="$(arg map_file)" />

  <!-- MOVE_BASE -->
  <include file="$(find jeep_nav)/launch/move_base.launch" />

  <!-- Determine whether to run Rviz or not & set Rviz config file-->
  <arg name="use_rviz" default="true" />
  <arg name="rvizconfig" default="$(find jeep_nav)/rviz/jeep.rviz"/>
  <!-- Launching Rviz -->
  <node if="$(arg use_rviz)" name="rviz" pkg="rviz" type="rviz" respawn="false" args="-d $(arg rvizconfig)"/>

  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />
  <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />
  <!-- Start service server that responds with a plan for global path planning -->
  <node pkg="jeep_nav" name="a_star_solution" type="a_star.py" output="screen"/> 

</launch>

Thank you and if you need information, please let me know.

[hoanggiang]

One possible solution is that you can publish odom frame from world and let amcl localizes your robot in map frame.
Add this in your launch file

<node pkg="tf2_ros" type="static_transform_publisher" name="odom_world" output="screen" args="0 0 0 0 0 0 odom world" />

Now you have 2 separated trees, one with world, odom and base_link, one with map. You need to localize your odom frame using amcl. If you don’t have amcl, then you need to publish your own localization (odom frame in map frame).

[Ayush_G]

Hi @asibarra98,

It seems like you would need to add a ROS Differential Base prim to your stage. The Differential Base bridge is responsible for publishing the transform between your robot’s base link and the odom frame, publishing odometry to the /odom topic, as well as subscribing to the /cmd_vel topic (geometry_msgs/Twist Message type).
You can follow the tutorial on adding the ROS Differential Base here.

Additionally as @hoanggiang suggested, if you are not using amcl you can setup your own ROS node (or setup a static_transform_publisher) for publishing the transform between map and odom frame.