Fix/path smoothing robot radius

[ShiboWork]

Reference issue

• fix Bug: path_smoothing() Ignores robot_radius, Causing Smoothed Paths to Violate Obstacle Clearance #1230
  Fixes path smoothing safety issue discussed in Bug: path_smoothing() Ignores robot_radius, Causing Smoothed Paths to Violate Obstacle Clearance #1230

What does this implement/fix?

This PR fixes an issue in the path_smoothing() function, where the collision checking via line_collision_check() did not take robot_radius into account correctly. This caused the smoothed path to pass dangerously close to obstacles.

• Modified line_collision_check() to check collision along finite-length line segments and incorporate robot_radius.
• Updated path_smoothing() logic to use this corrected check.
• Added a new unit test to verify that smoothed paths maintain clearance from obstacles based on robot radius.

Additional information

• Confirmed original vs smoothed paths via animation and test assertions.

CheckList

• Did you add an unittest for your new example or defect fix?
• Did you add documents for your new example? N/A (not a new algorithm)
• All CIs are green? (You can check it after submitting)

[Copilot]

Pull Request Overview

This PR ensures the path smoothing routine respects the robot’s radius by updating collision checks and adding a safety-focused unit test.

• Expanded line_collision_check to sample finite-length segments and inflate obstacles by robot_radius.
• Updated path_smoothing to pass robot_radius into collision checks.
• Added a new test verifying no smoothed path point encroaches on obstacles.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
tests/test_rrt_with_pathsmoothing_radius.py	New test ensuring smoothed path maintains clearance.
PathPlanning/RRT/rrt_with_pathsmoothing.py	Modified collision logic and updated function calls.

Comments suppressed due to low confidence (2)

tests/test_rrt_with_pathsmoothing_radius.py:43

• [nitpick] Using a strict '>' may fail when a point lies exactly at the clearance boundary. Consider using '>=' if touching the safety radius is acceptable or adjust the test to account for floating-point tolerances.

assert d > min_safe_dist, \

PathPlanning/RRT/rrt_with_pathsmoothing.py:76

• [nitpick] The variable 'size' represents an obstacle radius. Rename it to 'obs_radius' or 'radius' for clearer semantics.

for (ox, oy, size) in obstacle_list:

[AtsushiSakai]

Thank you for great PR!!. I have some small comments. PTAL.