Fix numerical precision issues in quaternion to RPY conversion#811
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roman-y-wu wants to merge 9 commits intoros2:rollingfrom
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Fix numerical precision issues in quaternion to RPY conversion#811roman-y-wu wants to merge 9 commits intoros2:rollingfrom
roman-y-wu wants to merge 9 commits intoros2:rollingfrom
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added 3 commits
July 24, 2025 21:04
Addresses numerical precision errors that occur during quaternion-to-matrix conversion, particularly near gimbal lock singularities. When matrix elements contain small numerical errors (around 1e-12), the atan2 function can return incorrect angles, such as 45° instead of 0° for roll values. Changes: - Add epsilon thresholding (1e-10) to matrix elements before RPY computation - Improve singularity detection to handle near-singular cases - Add safety checks to prevent division by near-zero cosine values - Protect atan2 calls when both arguments are very small - Apply fixes to both Matrix3x3::getEulerYPR() and tf2::impl utilities - Update .gitignore with comprehensive build and temporary file patterns This resolves issues where tf2_echo and other tf2 tools would report incorrect RPY angles due to floating-point precision limitations.
Changes the epsilon threshold from 1e-10 to 1e-8 to be more conservative and avoid interfering with legitimate small values in normal quaternion conversions. The 1e-8 threshold still effectively catches the numerical precision errors that cause incorrect RPY results while ensuring existing tests continue to pass. Analysis showed that quaternion-to-matrix conversion preserves error magnitude, so a threshold of 1e-8 provides adequate safety margin above typical floating-point precision errors without affecting normal operations.
- Reorder headers to follow cpplint convention (C++ system headers first) - Remove trailing whitespace from empty lines - Addresses cpplint and uncrustify test failures
ahcorde
requested changes
Jul 28, 2025
Signed-off-by: Roman Wu <me@romanwu.com>
mjcarroll
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Generally looks good to me, but I would like to see some tests added around this singularity case.
added 2 commits
August 11, 2025 12:10
mjcarroll
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One more change here, but I think we are good.
Signed-off-by: Roman Wu <me@romanwu.com>
ahcorde
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Aug 18, 2025
Signed-off-by: Alejandro Hernández Cordero <ahcorde@gmail.com>
Signed-off-by: Alejandro Hernandez Cordero <ahcorde@gmail.com>
ahcorde
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Aug 18, 2025
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Pulls: #811
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ahcorde
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singularityGimbalLock is failing
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Description
Fixes #796
Addresses numerical precision errors that occur during quaternion-to-matrix conversion, particularly near gimbal lock singularities. When matrix elements contain small numerical errors (around 1e-12), the atan2 function can return incorrect angles, such as 45° instead of 0° for roll values.
Changes:
This resolves issues where tf2_echo and other tf2 tools would report incorrect RPY angles due to floating-point precision limitations.
Is this user-facing behavior change?
precision issues
- Before: RPY (degree) [45.000, -90.000, 0.000] (incorrect)
- After: RPY (degree) [0.000, -90.000, 0.000] (correct)
- Near gimbal lock singularities
- When quaternions come from tf2 lookupTransform operations
- When dealing with transformations that should have zero roll/yaw but show small numerical errors
Did you use Generative AI?
No.
Additional Information