The ISSAC SIM has a bug in its IMU and cannot be used for SLAM. I tried Vins-Mono and orbslam3. None of them work with IMU.
I encountered a lot of problems along the way. For example, when the robot moves backwards in a straight line, the IMU angular velocity reading has a y value of 0.08. But when the robot moves forward in a straight line, the y value of the IMU angular velocity reading changes to 2. I don’t know why.
If the IMU frequency is greater than 100Hz, I run： rosrun teleop_twist_keyboard teleop_twist_keykey.py. When the robot is stationary, the IMU measurement is also constantly changing. And the higher the IMU frequency, the greater the noise. Sometimes I see the coordinates of the robot body changing, even though the robot is not moving.
To sum up, I think IMU for the ISSAC SIM simulator so far are problematic and cannot be used to do SLAM.