From d4c479cb6447dbfd920bbe3e0204b70a1d5fbb03 Mon Sep 17 00:00:00 2001 From: Will Bainbridge Date: Fri, 20 Oct 2017 16:02:43 +0100 Subject: [PATCH] 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. --- .../linearAxialAngularSpring/linearAxialAngularSpring.C | 4 ++-- src/rigidBodyDynamics/restraints/linearDamper/linearDamper.C | 4 ++-- .../sphericalAngularDamper/sphericalAngularDamper.C | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/src/rigidBodyDynamics/restraints/linearAxialAngularSpring/linearAxialAngularSpring.C b/src/rigidBodyDynamics/restraints/linearAxialAngularSpring/linearAxialAngularSpring.C index 8f0b6143e5..f9525e4236 100644 --- a/src/rigidBodyDynamics/restraints/linearAxialAngularSpring/linearAxialAngularSpring.C +++ b/src/rigidBodyDynamics/restraints/linearAxialAngularSpring/linearAxialAngularSpring.C @@ -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); } diff --git a/src/rigidBodyDynamics/restraints/linearDamper/linearDamper.C b/src/rigidBodyDynamics/restraints/linearDamper/linearDamper.C index d3e4e063da..da58d2fcc5 100644 --- a/src/rigidBodyDynamics/restraints/linearDamper/linearDamper.C +++ b/src/rigidBodyDynamics/restraints/linearDamper/linearDamper.C @@ -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); } diff --git a/src/rigidBodyDynamics/restraints/sphericalAngularDamper/sphericalAngularDamper.C b/src/rigidBodyDynamics/restraints/sphericalAngularDamper/sphericalAngularDamper.C index 8ef17486b7..5cec794d04 100644 --- a/src/rigidBodyDynamics/restraints/sphericalAngularDamper/sphericalAngularDamper.C +++ b/src/rigidBodyDynamics/restraints/sphericalAngularDamper/sphericalAngularDamper.C @@ -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); }