removed admittance_transforms_ struct and relevant functions as it acts just as a intermediary storage

[mgeethik]

Resolves #505

Description

After thorough investigation of the issue raised by @destogl in #505 , it was found that the admittance_transforms_ structure introduced unnecessary duplication of frame transformation data already derivable at runtime. This PR removes admittance_transforms_ and instead computes all necessary transforms directly within the update() function, storing only the relevant ones in admittance_state_ where needed.

This change simplifies the codebase and avoids duplicated state between admittance_state_ and admittance_transforms_, improving clarity, modularity, and maintainability.

Changes made

• Removed get_all_transforms() and the admittance_transforms_ member.
• Moved all frame transform calculations (world→base, base→sensor, base→control, base→CoG) directly into the update() function.
• Reused temporary local variables (Eigen::Isometry3d) instead of storing redundant transforms.

Testing

Ran the existing controller tests to verify correctness.
This is the output of the test:

build/admittance_controller/Testing/20250430-1058/Test.xml: 2 tests, 0 errors, 0 failures, 0 skipped
build/admittance_controller/test_results/admittance_controller/test_admittance_controller.gtest.xml: 36 tests, 0 errors, 0 failures, 0 skipped
build/admittance_controller/test_results/admittance_controller/test_load_admittance_controller.gtest.xml: 1 test, 0 errors, 0 failures, 0 skipped

Summary: 39 tests, 0 errors, 0 failures, 0 skipped

Please let me know if this is fine or any changes are required

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.81%. Comparing base (945a360) to head (55b07ac).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1668      +/-   ##
==========================================
- Coverage   84.81%   84.81%   -0.01%     
==========================================
  Files         127      127              
  Lines       12114    12108       -6     
  Branches     1036     1036              
==========================================
- Hits        10275    10269       -6     
  Misses       1501     1501              
  Partials      338      338              

Flag	Coverage Δ
unittests	84.81% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../include/admittance_controller/admittance_rule.hpp	100.00% <ø> (ø)
...ude/admittance_controller/admittance_rule_impl.hpp	92.62% <100.00%> (-0.20%)	⬇️

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[saikishor]

@mgeethik I've added some comments

[saikishor]

Suggested change

	current_joint_state.positions, parameters_.kinematics.base, tf);
	current_joint_state.positions, parameters_.control.frame.id, tf);

Shouldn't it be this?

ros2_controllers/admittance_controller/include/admittance_controller/admittance_rule_impl.hpp

Lines 167 to 169 in 945a360

	success &= kinematics_->calculate_link_transform(
	current_joint_state.positions, parameters_.control.frame.id,
	admittance_transforms_.base_control_);

[saikishor]

In place of tf.rotation shouldn't it use parameters_.gravity_compensation.frame.id transform?

[mgeethik]

true. I will change this.

[saikishor]

LGTM