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how to open/close nextage grippers in simulation

asked 2016-12-06 09:33:12 -0500

robotfan gravatar image

updated 2016-12-06 16:00:40 -0500

130s gravatar image

I am using rtmros_nextage in simulation and would like the robot to pick up objects. So far I cannot even open or close the grippers. Minimal example that does not do anything:

  1. rtmlaunch nextage_ros_bridge nextage_ros_bridge_simulation.launch
  2. roslaunch nextage_moveit_config moveit_planning_execution.launch
  3. ipython -i `rospack find nextage_ros_bridge`/script/nextage.py

Now running robot._hands.gripper_l_open() or robot._hands.gripper_l_close() does not have any effect. What do I do wrong? Any help appreciated.


UPDATE: Thank you for your answer. So what I did is (as far as I can see) excatly what you describe in the tutorial. This is copy-pasted from my ipython:

In [1]: robot._hands.gripper_l_close()
dout, mask:
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2]
Out[1]: True

Not sure if the last line means the closing was successful, but I cannot see any movement of the gripper in the simulation and it should be visible shouldn't it?

rosversion nextage_ros_bridge
0.7.11
rospack find nextage_ros_bridge
/home/USERNAME/catkin_ws/src/rtmros_nextage/nextage_ros_bridge

And I am using ROS Indigo.

I also tried what the user you linked was trying - but executing robot._hands.handtool_l_eject()or robot._hands.handtool_l_attach() behaves the same way: output is True, but I cannot see anything happening in the simulation.

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answered 2016-12-06 14:34:03 -0500

130s gravatar image

updated 2016-12-06 16:10:22 -0500

Not sure which document you're referring to, and I'm not sure either if the same issue though, 2 months ago another user reported issue of gripper commands, so I updated the tutorial. There's still another user who's having an issue, so there may be an issue persisting.

Try the tutorial first, and if any commands behave differently from your expectation, please open a ticket on the issue tracker describing: - what you expect and what actually happen. - output print (eg. this) - output of the following commands:

rosversion nextage_ros_bridge
rospack find nextage_ros_bridge

UPDATE: Ah, sorry I missed that you're on simulation, not on a real robot. I don't think the gripper operation is supported in neither on OpenRTM sim (default) nor on simulation with dynamic powered by Gazebo (experimental).

If you really need to simulate grippers on simulation for NEXTAGE, I'd suggest you add custom grippers on the Gazebo package (see above link, though not well documented yet), assuming there are some gripper implementations for Gazebo in ROS. If you need an assistance, open a ticket on the issue tracker (or if your team has a real robot as well and is subscribing to the support service, please use that for guaranteed responses).

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Comments

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My comment to this is too long, so I posted it as an answer :-/ Let me know if there is a better way to handle the small character limit on comments. Sorry for the inconvenience!

robotfan gravatar image robotfan  ( 2016-12-06 15:33:09 -0500 )edit

I just moved your post in the answer section to your original post ;)

130s gravatar image 130s  ( 2016-12-06 16:01:18 -0500 )edit
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Ah, thanks for the formatting. And your update on simulation "solves" the issue or at least explains it. So instead of actually closing grippers, I would somehow fake a grasp? Do you have a pointer to a tutorial or so, how to 'fake' grasping an object in openRTM sim? Thanks.

robotfan gravatar image robotfan  ( 2016-12-06 16:18:57 -0500 )edit

Not that I know of, unfortunately. I know for Baxter grippers are simulated on Gazebo, and I've been wanting to add the feature to NEXTAGE but never realized. Opening a feature request on the issue tracker might accelerate things.

130s gravatar image 130s  ( 2016-12-06 17:37:41 -0500 )edit

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Asked: 2016-12-06 09:33:12 -0500

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Last updated: Dec 06 '16