Non zero angular velocity at the end of the path

[saeedarabi92]

Hi. Thank you for providing this great project for the community.
I am experimenting with path tracker and I realized that when the robot reaches to the end of path (or paused by publishing to /pause topic), after a few seconds, the angular velocity becomes non zero and causing the robot to rotate in place (please see the image below). What would be the reason of this behavior and how can I fix that?

[Timple]

Is it perhaps trying to match the orientation of your last point provided?

[saeedarabi92]

Hi @Timple ; Thank you for your prompt response.
I think the issue was in specifying the l (Following distance from robot's rotational point to trajectory) parameter. When I changed l to a value greater than zero, that behavior disappeared.
Back to your point on matching the orientation... I am not sure if that is the case! I tried the following path and the robot did not turn!

  seq: 1
  stamp:
    secs: 0
    nsecs:         0
  frame_id: 'path_frame'
poses:
  -
    header:
      seq: 0
      stamp:
        secs: 0
        nsecs:         0
      frame_id: 'path_frame'
    pose:
      position:
        x: 0.0
        y: 0.0
        z: 0.0
      orientation:
        x: 0.0
        y: 0.0
        z: 0.0
        w: 1.0
  -
    header:
      seq: 1
      stamp:
        secs: 0
        nsecs:         0
      frame_id: 'path_frame'
    pose:
      position:
        x: 0.0
        y: 0.0
        z: 0.0
      orientation:
        x: 0.0
        y: 0.0
        z: -0.707
        w: 0.707

Shouldn't the robot turn in-place according to the above path?