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JointTrajectoryPoint time_from_start Question

asked 2021-02-20 21:43:25 -0600

swiz23 gravatar image

updated 2021-02-21 06:30:17 -0600

gvdhoorn gravatar image

Just a question about the time_from_start parameter in the JointTrajectoryPoint message...

Does it mean that the JointTrajectoryPoint should already be done executing when the time_from_start value is reached? Or does it mean that the JointTrajectoryPoint should start executing once the time_from_start value is reached?

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answered 2021-02-21 06:10:02 -0600

gvdhoorn gravatar image

updated 2021-02-21 06:31:28 -0600

Does it mean that the JointTrajectoryPoint should already be done executing when the time_from_start value is reached? Or does it mean that the JointTrajectoryPoint should start executing once the time_from_start value is reached?

A JointTrajectoryPoint encodes the state of the system at the delta-t from the start of the execution of the JointTrajectory.

Personally, I don't believe it's possible to "execute a JointTrajectoryPoint", as it's a point, but if you're asking whether the manipulator should have traversed the trajectory segment defined by pt_(n) - pt_(n-1) at pt_(n).time_from_start, then: yes.

In your words:

the JointTrajectoryPoint should already be done executing when the time_from_start value is reached


Edit: it might help if you see JointTrajectory not as a series of motion commands (which they aren't), but as a data structure describing a spline through the JointTrajectoryPoints.

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Thanks! That helps a lot

swiz23 gravatar image swiz23  ( 2021-02-22 11:42:29 -0600 )edit

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Asked: 2021-02-20 21:43:25 -0600

Seen: 66 times

Last updated: Feb 21