BUG: RBD: restraints: Corrected restraint force transformations

The restraints generate either joint-local (tau) or global (fx) forces.
At the moment they all generate the latter. This change corrects three
of the four restraints so that the forces are in the gobal coordinate
system and not the local coordinate system of the body.

The problem with this is that the forward dynamics code then transforms
most of the forces back to the body local coordinate system. A better
solution would be to associate restraints which are more sensibly
defined in a local frame with the joints instead of the bodies, and
return the forces as part of the tau variable.
This commit is contained in:
Will Bainbridge
2017-10-20 16:02:43 +01:00
committed by Andrew Heather
parent 79ad0f0613
commit 4dd8b3f247
3 changed files with 6 additions and 6 deletions

View File

@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2016-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -133,7 +133,7 @@ void Foam::RBD::restraints::linearAxialAngularSpring::restrain
}
// Accumulate the force for the restrained body
fx[bodyIndex_] += spatialVector(moment, Zero);
fx[bodyIndex_] += model_.X0(bodyID_).T() & spatialVector(moment, Zero);
}

View File

@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2016-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -85,7 +85,7 @@ void Foam::RBD::restraints::linearDamper::restrain
}
// Accumulate the force for the restrained body
fx[bodyIndex_] += spatialVector(Zero, force);
fx[bodyIndex_] += model_.X0(bodyID_).T() & spatialVector(Zero, force);
}

View File

@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2016-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -85,7 +85,7 @@ void Foam::RBD::restraints::sphericalAngularDamper::restrain
}
// Accumulate the force for the restrained body
fx[bodyIndex_] += spatialVector(moment, Zero);
fx[bodyIndex_] += model_.X0(bodyID_).T() & spatialVector(moment, Zero);
}