fix(tricycle_controller): check non-strict inequality for M_PI_2 steering boundary

[joseph-ros2-dev]

This PR addresses the edge case in the steering error attenuation mechanism of the tricycle controller.

Description

When the steering angle error (alpha_delta) is exactly M_PI_2 (e.g. at the start of a zero-radius spin maneuver from a straight-line driving state), the strict inequality check alpha_delta > M_PI_2 evaluates to false. The control logic then falls through to the else branch, calculating scale = cos(M_PI_2).

Due to double-precision floating-point limits, cos(M_PI_2) yields ~6.12e-17 instead of the expected 0.01 (1% speed limit), virtually halting the wheel command entirely on the first control cycle.

Solution

Changing the strict inequality > to >= in the boundary check allows the controller to correctly apply the intended 0.01 speed limit when the error is exactly at the M_PI_2 boundary.

Fixes #2391

[saikishor]

Hello,

Can you add a test case for this change?

[joseph-ros2-dev]

Hello @saikishor,

I have added the unit test velocity_attenuation_at_pi_2_boundary to test_tricycle_controller.cpp to verify this boundary behavior. The local test successfully passed (100% passed).

Please let me know if you have any further feedback. Thanks!

[saikishor]

Hello @saikishor,

I have added the unit test velocity_attenuation_at_pi_2_boundary to test_tricycle_controller.cpp to verify this boundary behavior. The local test successfully passed (100% passed).

Please let me know if you have any further feedback. Thanks!

Good testing. Thanks for adding it

[christophfroehlich]

I'm not entirely sure if this state makes sense. This logic just reduces wheel speed until the steering angle is reached. why should it not stop if the delta_angle is Pi/2?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.65%. Comparing base (2850cc4) to head (5bcc2e1).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2392      +/-   ##
==========================================
+ Coverage   85.60%   85.65%   +0.04%     
==========================================
  Files         148      148              
  Lines       15829    15842      +13     
  Branches     1339     1339              
==========================================
+ Hits        13551    13569      +18     
+ Misses       1792     1788       -4     
+ Partials      486      485       -1     

Flag	Coverage Δ
unittests	85.65% <100.00%> (+0.04%)	⬆️

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

Files with missing lines	Coverage Δ
tricycle_controller/src/tricycle_controller.cpp	67.34% <100.00%> (+1.89%)	⬆️
...cycle_controller/test/test_tricycle_controller.cpp	92.45% <100.00%> (+0.72%)	⬆️

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