the same object's point cloud can't aligned well after rotate a few times

[mantouRobot]

Hi~
      I found that when I rotate the robot a few times, the same object's point cloud can't aligned very well. Is it normal?
      Thanks a lot~

[matlabbe]

Hi,

If there is no loop closures or proximity detections, yes it is normal. Do you have a picture of the problem?

[mantouRobot]

[matlabbe]

You may show the rtabmap's MapGraph in RVIZ to see if there are loop closure or proximity links (red or yellow links). Are you using external odometry linked to /base_link for example? If so, odometry may be drifting fast or you may have to verify your TF between your /base_link frame and the camera frame. If the TF is wrong, the point cloud will not align correctly.

[mantouRobot]

Hi~
      In my a few times rotation, one or two times may be loop closure, normally no loop closure except  step by step rotation. My odom is precise, both the tf. Even one or two times may be loop closure, it's just align the current point cloud, not all the point cloud before. I use the kinect.
      Thank u~

[matlabbe]

If odometry is precise, verify the TF between your base_link (the frame of your odometry) and the camera frame. If you rotate on-place, odometry is precise and point clouds don't match, there is effectively a problem with this TF (e.g. /base_link -> /camera_link is not equal to reality).