joint_trajectory_controller position hold mode

asked 2019-08-19 05:13:25 -0500

Eisenhorn gravatar image

Hello,

In http://wiki.ros.org/joint_trajectory_... a position hold mode mode is mentioned. I am not 100% percent sure what the expected behaviour should be. I would suggest, that if a certain pose is taken, the controller will hold this exact pose actively. Is that correct?

It is mentioned that "sending empty trajectory message from the topic interface" will enter this mode. I used rostopic send to the command topic and then just hitting tab for the default message. This wouldn't cause the expected behaviour.

Am I not following documentation correctly or is the expected behaviour a different one?

BR

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Comments

1

I'm not entirely sure (and can't check at the moment), but default behaviour for rostopic pub <etc> <tab tab> is to expand lists etc with at least a single element. For JointTrajectory msgs that would not equate to an "empty message".

You might want to try a simple Python script that sends an actual empty trajectory (ie: no points).

gvdhoorn gravatar imagegvdhoorn ( 2019-08-19 05:42:40 -0500 )edit

Thanks for your suggestion. I did send an emtpy message now: seq: 34
stamp:
secs: 0
nsecs: 0
frame_id: ''
joint_names: []
points: []
The following observations ware made: -No active holding of the current position -New goals are not accepted anymore

Eisenhorn gravatar imageEisenhorn ( 2019-08-19 09:21:56 -0500 )edit