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Perturbed rotation matrix is not perturbed in linearization when small angle is used #1172

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ebranlard opened this issue Jul 7, 2022 · 2 comments
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Perturbed rotation matrix is not perturbed in linearization when small angle is used #1172

ebranlard opened this issue Jul 7, 2022 · 2 comments
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@ebranlard
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Feature: Linearization Module: HydroDyn Type: Bug

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@ebranlard
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ebranlard commented Jul 7, 2022 •
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Bug description
The Orientation matrix is not perturbed when calling the function PerturbOrientationMatrix, when useSmlAngle is used.

The code hits the following line:

call SmllRotTrans( 'linearization perturbation', angles(1), angles(2), angles(3), OrientationTmp, ErrStat=ErrStat2, ErrMsg=ErrMsg2 )

OrientationTmp should actually be returned

Expected behavior
Return the Orientation matrix directly:

call SmllRotTrans( 'linearization perturbation', angles(1), angles(2), angles(3), Orientation, ErrStat=ErrStat2, ErrMsg=ErrMsg2 )

Impacted areas
The bug was introduced in 8364b53 as part of #1050.
It's mostly affecting dev right now, and only HydroDyn linearization is affected because other modules do not use SmallAngle.
@ebranlard ebranlard self-assigned this Jul 7, 2022
ebranlard added a commit to ebranlard/openfast that referenced this issue Jul 7, 2022
@ebranlard
Bug Fix: rotation matrix perturbation with small angles was wrong (Op…
ed6f6e7 
…enFAST#1172)
@ebranlard ebranlard mentioned this issue Jul 7, 2022
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@ebranlard ebranlard changed the title Perturbed rotation matrix is not perturbed in linearization when one angle is provided and small angle is used Perturbed rotation matrix is not perturbed in linearization when small angle is used Jul 7, 2022
@rafmudaf
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@ebranlard could you confirm that #1173 fixes this issue?

@ebranlard
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Yes, it fixes the issue!

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Feature: Linearization Module: HydroDyn Type: Bug
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@ebranlard @rafmudaf