Add a way to replace collision meshes upon MJCF conversion

[saikishor]

Description

This add a way to replace the collision defined for a link with a custom informaiton. For instance, remove meshes or primitive shapes and add capsules on mujoco end.

Adds a new replace_collision processed_inputs tag to the URDF→MJCF conversion tool, letting users fully replace a link's collision geometry with one or more user-authored MJCF primitives (capsules, boxes, etc.), including nested sub-bodies useful for swapping an expensive collision mesh

  <replace_collision link="forearm">                                                                                                                                                    
    <geom type="capsule" fromto="0 0 0 0 0 0.3" size="0.04"/>                                                                                                                           
    <geom type="capsule" fromto="0 0 0.3 0.1 0 0.3" size="0.03"/>                                                                                                                       
  </replace_collision> 

Is this user-facing behavior change?

NO

Did you use Generative AI?

Claude Sonnet/opus

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.08%. Comparing base (49a4155) to head (6006134).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #310      +/-   ##
==========================================
+ Coverage   82.68%   83.08%   +0.40%     
==========================================
  Files          35       35              
  Lines        5907     6047     +140     
  Branches      602      603       +1     
==========================================
+ Hits         4884     5024     +140     
  Misses        703      703              
  Partials      320      320              

Flag	Coverage Δ
unittests	83.08% <100.00%> (+0.40%)	⬆️

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Files with missing lines	Coverage Δ
...co_ros2_control/tests/test_urdf_to_mujoco_utils.py	99.87% <100.00%> (+0.01%)	⬆️

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