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Hi

I am new to ROS and RViz and am getting used to the display options. I am learning kinematics. As I understand it, when you click the TF box in RVIz, this will show you your link axes.

However, I would like to view the joint axes.

This is because I have been told the URDF axis orientation for the robot I am looking at is different to those you would find in a Denavit Hartenberg analysis (Its the KUKA KR210). I may have to apply further rotations to make them match. I would like a visual representation of the URDF joint orientations to aid my understanding as I go about finding the DH equations and HT's for each joint.

Is it possible to display the URDF joint axes, as opposed to the URDF link axes?

Thanks!


Originally posted by Wireline on ROS Answers with karma: 48 on 2017-09-11

Post score: 2

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1 Answer 1

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You need to have a /robot_description (loaded from urdf/xacro) and use the RobotModel visualization in rviz to see the joints. Expand RobotModel and there should be an item called 'Links', which via the 'Link Tree Style' option can be changed to 'Joints in Alphabetic Order' or 'Tree of links and joints'. With either of those it is possible to check 'Show Joint Axis' for any joint in the robot.

That is at least in the kinetic version since rviz 1.12.4. https://github.com/ros-visualization/rviz/pull/1029


Originally posted by lucasw with karma: 8729 on 2017-09-11

This answer was ACCEPTED on the original site

Post score: 2


Original comments

Comment by Wireline on 2017-09-11:
Apologies if this sounds confused, but I think what I am after is the "reference frames" of one joint to another, as opposed to just the plain old xyz axes. Its difficult to know the right questions to ask when you're learning!

Comment by lucasw on 2017-09-12:
I think I would need a diagram to completely follow here, but I wonder if you split every joint into two, a fixed parent with the translation and a child with the rotation (though many joints are all xyz or all rpy), and then did tf lookups between the frames in the middle would be what you want

Comment by lucasw on 2017-09-12:
But if you don't want to alter the urdf/xacro then you would have to look (programmatically) into the robot_description a do more complex tf lookups + additional operations to get the same thing, which I think is what @gvdhoorn is getting at.

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