Change KDL IK plugin joint weight parameters specification

[sea-bass]

Description

This is a potential fix for #2749.

It changes the KDL parameters introduced in #1671 from:

panda_arm:
  kinematics_solver: "kdl_kinematics_plugin/KDLKinematicsPlugin"
  kinematics_solver_search_resolution: 0.005
  kinematics_solver_timeout: 0.05

  joints: ["joint1", "joint2", "joint3", "joint4", "joint5", "joint6"]
  # Default weight for joints is 1.0 
  joint1:
    weight: 2.0
  joint5:
    weight: 1.5

to

panda_arm:
  kinematics_solver: "kdl_kinematics_plugin/KDLKinematicsPlugin"
  kinematics_solver_search_resolution: 0.005
  kinematics_solver_timeout: 0.05

  joints: ["joint1", "joint2", "joint3", "joint4", "joint5", "joint6"]
  # Default weight for joints is 1.0 
  weights:
    joint1:
      value: 2.0
    joint5:
      value: 1.5

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[sea-bass]

Ugh, seems like MoveIt Setup Assistant has some failures due to the addition of the nonzero velocity here: moveit/moveit_resources#198.

This is fixed by #2751, which I temporarily included in this branch as well to see if Humble CI passes.

[sjahr]

Do we need to update some moveit_resources packages?

[sea-bass]

Do we need to update some moveit_resources packages?

Actually, no, because none of the example configs even sets joint weights in the first place!

But ler's not merge this in yet, as we could also opt to fix generate_parameter_library

[rhaschke]

Why don't you simply use a map from joint name to weight (instead of an additional indirection layer):

  weights:
    joint1: 2.0
    joint5: 1.5

[sea-bass]

Why don't you simply use a map from joint name to weight (instead of an additional indirection layer):

  weights:
    joint1: 2.0
    joint5: 1.5

That does sound good, but I'm not sure if generate_parameter_library supports doing this at the moment. Looking at the examples: https://github.com/PickNikRobotics/generate_parameter_library?tab=readme-ov-file#mapped-parameters, seems like there has to be a field underneath the mapped parameters.

[rhaschke]

I'm not sure if generate_parameter_library supports doing this at the moment.

If it doesn't, you probably should fix that library. A library implementation shouldn't impose constraints on the kind of parameter structures available.

[Abishalini]

If humble CI jobs pass, would it make sense to merge this while a fix to generate_param_library is being worked on?
This would unblock other PRs in the repo

[sea-bass]

Seems there is interest in fixing CI for now, so will open up #2756 and we'll make sure we get that in for the next MoveIt 2 release.

[sea-bass]

Update: I think I fixed generate_parameter_library to be able to keep the old syntax: PickNikRobotics/generate_parameter_library#185

[gavanderhoorn]

@sea-bass: could the branch be deleted?