fix(lane_change): skip generating path if longitudinal distance difference is less than threshold

[zulfaqar-azmi-t4]

Description

Current behavior:

The number of lane change samples increases as ego vehicle approaches terminal start, due to the greater number of longitudinal acceleration samples.

The increase in lane change samples also leads to higher computational costs, as each sample generates a candidate path and undergoes various validations.

Proposed behavior:

Each lane change sample is computed based on the corresponding longitudinal acceleration sample.

As the ego vehicle approaches the terminal start, the distance differences between each lane change sample become smaller.

In this case, if the distance difference is small and the previous path is unsafe, it's likely that the new path with a small distance difference will also be unsafe. Therefore, it is feasible to skip generating paths with small distance differences and focus on those with larger differences instead.

Following are the illustrations of the proposed behavior

Before PR

Has more number of candidate path (5 samples) and processing time is between 7~10ms.

beforePR.mp4

After PR

Has less number of candidate path (3 sample) and processing time is between 5~8ms.

afterPR.mp4

Related links

Required #8362
Required launcher: autowarefoundation/autoware_launch#1108
Parent Issue:

• Link

How was this PR tested?

Notes for reviewers

None.

Interface changes

None.

Effects on system behavior

None.

[github-actions]

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[maxime-clem]

Code looks good and a quick test in Psim did not reveal any issue.

[codecov]

Codecov Report

Attention: Patch coverage is 25.00000% with 12 lines in your changes missing coverage. Please review.

Project coverage is 23.72%. Comparing base (e9dcf99) to head (a41fe97).
Report is 14 commits behind head on main.

Files	Patch %	Lines
...are_behavior_path_lane_change_module/src/scene.cpp	0.00%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8363      +/-   ##
==========================================
- Coverage   23.72%   23.72%   -0.01%     
==========================================
  Files        1379     1380       +1     
  Lines      101392   101409      +17     
  Branches    38522    38534      +12     
==========================================
+ Hits        24058    24061       +3     
- Misses      74913    74927      +14     
  Partials     2421     2421              

Flag	Coverage Δ		*Carryforward flag
differential	15.68% <25.00%> (?)
total	23.73% <ø> (+<0.01%)	⬆️	Carriedforward from 158b6d2

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