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Joint publisher with empty velocity and effort vector

asked 2011-07-20 12:15:43 -0500

diannay gravatar image


After reading the URDF and robot / joint state publisher related tutorials, I am able to see the joint messages published by the joint state publisher, but the velocity and effort fields are empty.(I am currently running ros-diamondback on linux) Then looking into the pr2_controller_manager tutorials, I was able to use the JointVelocityController Plugin (configured it to correspond the joints in my urdf file) and launched a spawner type pr2_controller_manager node taking these JointVelocityController as an argument. But using rostopic info on this node, it does not have any subscribed or published topics. What are some ways to generate these velocity and effort fields? I am trying to use the environment_server of motion_planning_common which requires valid joint messages with velocity components for collision detection but keep seeing the invalid joint state error mesesage.

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answered 2011-09-01 04:14:35 -0500

Wim gravatar image

The joint_state_publisher is a tool to verify the correctness of your URDF model, by visually inspecting the robot model as it moves. It is however not intended to be used for running your robot. For your own robot, you will have to write a node that reads the joint values from your HW/sim robot, and publish those on the joint_states topic. For the PR2 robot, this job is done by pr2_mechanism.

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answered 2011-07-28 08:02:43 -0500

tom temple gravatar image

I'm having the same problem. It seems like, in its current form, joint_state_publisher is incompatible with motion_planning_common. Is there a workaround? The project page suggest that one can set default values but doesn't elaborate on how.

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Asked: 2011-07-20 12:15:43 -0500

Seen: 1,196 times

Last updated: Sep 01 '11