Add prevent_look_ahead_poses_near_goal to fix oscillation #180
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added 2 commits
October 17, 2019 17:26
The code handles on-the-fly changes to these parameters just like all the others, so go ahead and make them dynamic: * min_samples * max_samples * global_plan_prune_distance * min_resolution_collision_check_angular * control_look_ahead_poses This is in preparation for adding a new parameter related to the last one in this list. It would be awkward for it to by dynamic while this is not.
Never look ahead to the last few poses of the plan in order to prevent oscillating forward and backward over the goal when the xy_goal_tolerance is small. Specified by new parameter prevent_look_ahead_poses_near_goal whose default is zero.
howardcochran
changed the title
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Hey, thanks for the PR; very valuable. I open another PR to melodic. I suppose you don't care anymore about merging this to kinetic, right? |
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In testing, I found that setting the new parameter
control_look_ahead_poses to 3 improved path following
accuracy very much. However, in cases where need to arrive
at a very precise goal (as by setting xy_goal_tolerance to 0.01),
it could cause the robot to overshoot the goal and then oscillate
back and forth over the goal indefinitely.
This new parameter fixes that by preventing
control_look_ahead_poses from selecting one of the last few
poses of the path.
Since this new dynamic parameter affects the behavior of an
existing parameter, it makes sense to make the existing
one dynamic also. For completeness, I made all remaining
parameters in the trajectory group be dynamic, as there is no
reason I can see not to do that.