What is the difference between joint_weights (KDLKinematics parameter) and distance_factor_ (JointModel class of moveit) parameter?

asked 2019-11-28 04:57:38 -0500

gabrielK gravatar image

updated 2019-11-28 08:22:58 -0500

Hi all

What is exactly the difference between the joint_weights (used to weight the joints in the kinematics plugin specified in the kinematics.yaml file and used in https://github.com/ros-planning/movei...) and the distance_factor_ (used to weight the joints when calculating the distance between two states in the configuration space (see https://github.com/ros-planning/movei...

I want to set the joint weights in a way that one unit movement of the joint closer to the end-effector have a smaller probability for collision than base joint unit movement (thus I want to set the joints in relation to the level arm distance for a kinematic chain robot). I figured out that setting the joint_weights as described, they are only used within the kinematic_plugin (moveit_core) but have no influence on the distance_factor_ and thus no influence on the distance calculation (distance metric) for the OMPL planner. Are the joint_weights only used for the inverse kinematics or also have an influence how it is sampled (when using the JointModel state space)? Why are they not coupled together or what are their differences?

Does it make sense to set the joint_weights and the distance_factor_ equally when planning with OMPL (JointModel state space) and KDLkinematics plugin?

Thanks for the help

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Related discussion on the MoveIt tracker: ros-planning/moveit#1446.

gvdhoorn gravatar image gvdhoorn  ( 2019-11-28 08:39:55 -0500 )edit

Thank you, I will continue the discussion there.

gabrielK gravatar image gabrielK  ( 2019-11-30 03:28:36 -0500 )edit