Large Velocity Warnings and Lidar Data Issues in LIO-SAM with ISAAC SIM (ROS2 Humble)

[REGATTE]

I am trying to use LIO-SAM with ISAAC SIM v4.2 on ROS2 Humble. The sensors have been configured as per the instructions in the README. The IMU and lidar data have matching timestamps and are being published at the same frequency.

I encountered an issue where the default lidar output from ISAAC SIM does not include ring data. To address this, I created a package to generate lidar data with ring information, which now appears correct in RViz. However, while running the full LIO-SAM pipeline, I am facing the following problems:

I see repeated warnings about large velocity and IMU-preintegration resets in the logs:

[lio_sam_imuPreintegration-3] [WARN] [1737002944.665420944] [lio_sam_imuPreintegration]: Large velocity, reset IMU-preintegration!
[lio_sam_imuPreintegration-3] [WARN] [1737002946.018486600] [lio_sam_imuPreintegration]: Large velocity, reset IMU-preintegration!

In RViz, the lidar data appears incomplete—only the top layer of the point cloud is visible.

Steps to Reproduce:

Use ISAAC SIM v4.2 and ROS2 Humble.
Configure IMU and lidar sensors according to the LIO-SAM README.
Ensure the IMU and lidar data have synchronized timestamps and identical frequencies.
Modify ISAAC SIM's lidar output to include ring data and visualize in RViz.
Run the full LIO-SAM pipeline.

Expected Behavior:
The system should process the IMU and lidar data without warnings, and the full lidar point cloud should be visible in RViz.

Observed Behavior:

Frequent warnings about large velocity and IMU-preintegration resets.
Only the top layer of the lidar data is visible in RViz.

Additional Context:
The lidar data with ring information seems to be correctly generated and visualized in RViz before running LIO-SAM. The issues arise during SLAM processing.

Any insights or suggestions would be greatly appreciated!

[ZhongmouLi]

have you solved this problem?