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I was following the tutorial on using the MoveIt Setup Assistant to create a MoveIt package for an industrial Robot.

In the Add Planning groups section, it is mentioned that adding a Kinematic Chain is generally preferred over add joints or add links.

But in this MoveIt tutorial, they use the Add Joints for the planning group right_arm and Add Links for the right_gripper group.

I want to know what is the difference between these two approaches. Which one is better and in what situation?

Thanks for all inputs!

Originally posted by bhavyadoshi26 on ROS Answers with karma: 95 on 2016-11-14

Post score: 1


1 Answer 1


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In terms of functionality for each approach, the srdf wiki page has descriptions for each.

In short,

  • A link automatically includes its parent joint
  • A joint automatically includes is child link
  • A chain implicitly defines the joints based on the two selected links (Based on the links in the chain, the set of joints in the chain is implicitly defined. The joints that correspond to a chain are the parent joints for the links in the chain, except the parent joint of the base_link)

As to why the ROS-I tutorial specifically suggests using chains I can only guess that it is easier, less error prone, and/or more suitable to the IK solvers...

Originally posted by BrettHemes with karma: 525 on 2016-11-14

This answer was ACCEPTED on the original site

Post score: 0


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