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joint_trajectory_controller - Always dropping first trajectory point #291

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agutenkunst opened this issue Aug 11, 2017 · 6 comments

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@agutenkunst
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commented Aug 11, 2017

If a trajectory has no specified start time (0) and time_from_start of the first point is zero the first point will always be dropped.

Changing


< to <= stops this behaviour.

Not sure if this would be the best fix.

Any comments?

@bmagyar

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commented Aug 11, 2017

Yes as that'd leave no time for your arm to make it to the first point. Better to fill time_from_start for the first point too.

@ipa-mdl

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commented Aug 11, 2017

time_from_start == 0 just holds for the starting point of a trajectory, if any.
And this starting point should better match the actual position of the actuator ;)

@agutenkunst

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commented Aug 14, 2017

Just noticed that using OMPL there will always be the warning that the first point has been dropped which at first sounds like something you would not want a controller todo. Knowing that at time_from_start = 0 state == current_state seems pretty implicit.

@bmagyar

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commented Mar 23, 2018

Any update on this?

@moucrob

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commented Jul 26, 2018

I agree, still get displayed the warn
[ WARN] [1532615030.341235239]: Dropping first 1 trajectory point(s) out of 11, as they occur before the current time. First valid point will be reached in 0.466s.
But now the robot at least does the job, thanks!

Edit :
Here is the strict inequality to modify :
/opt/ros/kinetic$ grep -r "return time < point_start_time;" * .[!.]*

include/joint_trajectory_controller/joint_trajectory_msg_utils.h:
return time < point_start_time;

@jschleicher

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commented Oct 25, 2018

I'm working on this during WMD18

jschleicher added a commit to PilzDE/ros_controllers that referenced this issue Oct 25, 2018
dont print warning about dropped first point, if it is expected behav…
…iour

The warning about dropped points isn's useful, if the first point just contains
the expected start point. Dropping it is expected behaviour, thus degrading this
to a debug output message.

A subsequent feature could be to check the current position against the
parametrized tolerance of this point.

Closes ros-controls#291
jschleicher added a commit to PilzDE/ros_controllers that referenced this issue Oct 25, 2018
dont print warning about dropped first point, if it is expected behav…
…iour

The warning about dropped points isn's useful, if the first point just contains
the expected start point. Dropping it is expected behaviour, thus degrading this
to a debug output message.

A subsequent feature could be to check the current position against the
parametrized tolerance of this point.

Closes ros-controls#291
ipa-mdl added a commit to PilzDE/ros_controllers that referenced this issue Oct 27, 2018
dont print warning about dropped first point, if it is expected behav…
…iour

The warning about dropped points isn's useful, if the first point just contains
the expected start point. Dropping it is expected behaviour, thus degrading this
to a debug output message.

A subsequent feature could be to check the current position against the
parametrized tolerance of this point.

Closes ros-controls#291

@graiola graiola closed this in #367 Oct 29, 2018

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