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MoveIt! Access the pose of a CollisionObject

asked 2014-06-13 13:09:25 -0500

courrier gravatar image

updated 2014-06-16 12:48:42 -0500

Hi all,

I need to perform transformations between all objects manipulated by the robot. So I intended to create a thread to publish a tf::Transform at the center of each CollisionObject at, say, 50Hz. But to do that I need to access the pose of the collision objects in real time with respect to some frame (base_link for instance). Is this pose published somewhere in a topic, accessible through a service or is present in some field?

I am the one defining the initial position of all CollisionObject and asking the robot to take/leave this object, so thanks to the position of the end effector I could update my own copy of the pose but:

1) This value is necessarily known by MoveIt! to display the objects 2) It's annoying to wonder when the pose has or has not changed 3) If I do it the pose would be duplicated with the internal value of MoveIt!

Another question: is the field frame_id of a CollisionObject used by MoveIt? I would like to anchor an object (e.g. a cup of tea) to another (e.g. a tray) and ask the robot to manipulate the tray (with moveit_msgs::AttachedCollisionObject.lik_name = end effector of the robot). The goal is obiously to keep the cup fastened to the tray. I wanted to set the frame_id of the cup to the tray like I would so with a regular RViz marker for that but apparently this field is not used, the two CollisionObjects are not linked. Any clue to achieve this goal?

Many thanks for your help

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answered 2014-06-13 17:43:07 -0500

fergs gravatar image

You could subscribe to the "monitored_planning_scene" topic (which is what the RVIZ plugins do). This will publish the current planning scene, which includes changes to collision objects and attached objects. There is also a service call which you can you use to get the initial state of the planning scene since the published topic includes only diffs.

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Thanks I that is what I do now it works. Also I added a new question related to these frames.

courrier gravatar imagecourrier ( 2014-06-16 13:34:24 -0500 )edit

As for the frames, yes the frame is used, but I believe (unless it has been recently fixed) you can only use frames which are part of the robot as the RobotState class doesn't track the poses of non-robot frames. I think you will have to attach both objects to the end effector.

fergs gravatar imagefergs ( 2014-06-16 15:19:52 -0500 )edit

That's what I did in the end yes. Thanks

courrier gravatar imagecourrier ( 2014-06-27 11:53:10 -0500 )edit

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Asked: 2014-06-13 13:09:25 -0500

Seen: 604 times

Last updated: Jun 16 '14