Slam Map Builder and rosbags

Hello to all, I have been trying to simulate Lidar SLAM using the Automated Driving Toolbox with Unreal implementation. So, I am creating ros2bags which I then convert to ros1bags .bag files to use in Matlab's SLAM.(for reference, Simulink provides pointcloud2 which I convert with a node to laserscan msgs)

My problem is with the Odom Topic. I have tried having in my .bag file, an /odom topic with nav_msgs/Odometry and then geometry_msgs/PoseStamped and in both cases SLAM finds my Lidar topic but I get N/A in my Odomo Topic.

Since the documentation for implementing Matlab with ROS in general is lacking a bit, can somebody provide the message types needed or topic names needed for Odom in this case?

Answer 1

[Akshai Manchana]

Hi Angelos,

We only support the following two message types to represent the odometry data 'tf/tfMessage', 'tf2_msgs/TFMessage'. To learn more about these message types look at the example. These messages store 'geometry_msgs/PoseStamped' within it.

Refer to our documentation for more details.

Answer 2

[Pratyush Swain]

Hey Angelos,

I understand that you are facing issues subscribing to values through the '/odom' topic. To troubleshoot this problem, you can follow these steps:

1. Please verify the topic source and type by using the following commands in command window.

rostopic echo /odom % returns the data going through the topic 
rostopic info /odom % returns information regarding message type,publisher,subscriber 

You can go through ros_topic_commands for more information

2. Please check the structure of 'nav_msgs/Odometry' or 'geometry_msgs/PoseStamped' messages being published on the '/odom' topic. For example - the 'geometry_msgs/PoseStamped' message type includes the position and orientation values separately.

Hope this helps.