MotionPlanning in Moveit only partly works?

Question

Hello List,

Using Indigo I created a setup with moveit setup assistent and an urdf for our crustcrawler arm. The urdf is adapted from the smart_arm_robot.xacro from ua-ros-pkg. The urdf works fine using rviz and joint_state_publisher.

But with Planning Request in Moveit/Rviz the eef-joint (wrist_roll_joint) gets DETACHED from the rest of the arm. Normally the rest of the arm should follow, but it does NOT move while the (moved) eff-joint immediatly turns red.

The moveit-command however DOES work. I can see the moves in Rviz when I give e.g. "go rand". Also the pr2 example does work perfectly. You can find my setup in http://fwn06.housing.rug.nl/ros

I only used the setup wizard and used an urdf I am fairly confidant about. Why does the planning in MotionPlanning not work ?

Thanks in advance, Sietse

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Originally posted by Sietse on ROS Answers with karma: 168 on 2015-03-30

Post score: 0

Answer 1

To answer my own question: I had to flag "Allow Approximate IK Solutions" to get it to work.

I don't know why this is needed (of how I could have known this), but for the moment it works for me.

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Originally posted by Sietse with karma: 168 on 2015-04-01

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by gvdhoorn on 2015-04-01:
That option is almost always needed to work around the fact that your manipulator has < 6dofs, and the MoveIt interactive markers control a 6D Pose. The IK plugin used (probably KDL) cannot solve for a 6D pose with less than 6dof in your robot, hence the need to allow approximate solutions.

Comment by Sietse on 2015-04-01:
OK, clear. Thanks!