rigidBodyDynamics: Added rotating joint
This joint allows two bodies to rotate relative to each other at a
specified speed. The relative motion is completely specified, so this
joint has zero degrees of freedom.
It could be used, for example, to attach a rotating propeller to a
moving ship:
bodies
{
hull
{
...
}
propeller
{
type rigidBody;
// Dynamic properties
mass ...;
centreOfMass ...;
inertia ...;
// The propeller is connected to the hull
parent hull;
// The position relative to the hull
transform (1 0 0 0 1 0 0 0 1) (20 0 0);
// Rotation settings
joint
{
type rotating;
omega (6 0 0);
}
}
}
This commit is contained in:
Will Bainbridge
59
applications/test/rigidBodyDynamics/doublePendulumAndRotor
Normal file
59
applications/test/rigidBodyDynamics/doublePendulumAndRotor
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@ -0,0 +1,59 @@
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solver
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{
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type symplectic;
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}
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bodies
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{
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bar1
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{
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type rigidBody;
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mass 3;
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centreOfMass (0 -0.5 0);
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inertia (0.2575 0 0 0.015 0 0.2575);
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parent root;
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transform (1 0 0 0 1 0 0 0 1) (0 0 0);
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joint
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{
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type Rz;
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}
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outline ((0 0 0) (0 -1 0));
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}
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bar2
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{
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type rigidBody;
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mass 3;
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centreOfMass (0 -0.5 0);
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inertia (0.2575 0 0 0.015 0 0.2575);
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parent bar1;
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transform (1 0 0 0 1 0 0 0 1) (0 -1 0);
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joint
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{
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type Rz;
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}
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outline ((0 0 0) (0 -1 0));
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}
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rotor
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{
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type rigidBody;
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mass 3;
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centreOfMass (0 -0.5 0);
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inertia (0.2575 0 0 0.015 0 0.2575);
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parent bar2;
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transform (1 0 0 0 1 0 0 0 1) (0 -1 0);
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joint
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{
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type rotating;
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omega (0 0 1);
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}
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outline ((0 0 0) (0 -1 0));
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}
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}
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g (0 -9.81 0);
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q (1.5707963267948966 0 0);
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deltaT 0.01;
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endTime 20;
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@ -27,6 +27,7 @@ joints/Pa/Pa.C
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joints/Pxyz/Pxyz.C
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joints/rigid/rigid.C
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joints/rotating/rotating.C
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joints/function/function.C
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joints/functionDot/functionDot.C
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106
src/rigidBodyDynamics/joints/rotating/rotating.C
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106
src/rigidBodyDynamics/joints/rotating/rotating.C
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@ -0,0 +1,106 @@
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/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration | Website: https://openfoam.org
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\\ / A nd | Copyright (C) 2018-2022 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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\*---------------------------------------------------------------------------*/
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#include "rotating.H"
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#include "rigidBodyModelState.H"
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#include "addToRunTimeSelectionTable.H"
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// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
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namespace Foam
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{
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namespace RBD
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{
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namespace joints
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{
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defineTypeNameAndDebug(rotating, 0);
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addToRunTimeSelectionTable
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(
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joint,
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rotating,
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dictionary
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);
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}
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}
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}
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// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
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Foam::RBD::joints::rotating::rotating
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(
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const rigidBodyModel& model,
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const dictionary& dict
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)
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:
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joint(model, 0),
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omega_(Function1<vector>::New("omega", dict))
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{}
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Foam::autoPtr<Foam::RBD::joint> Foam::RBD::joints::rotating::clone() const
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{
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return autoPtr<joint>(new rotating(*this));
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}
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// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
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Foam::RBD::joints::rotating::~rotating()
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{}
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// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
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void Foam::RBD::joints::rotating::jcalc
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(
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joint::XSvc& J,
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const rigidBodyModelState& state
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) const
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{
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const scalar t = state.t(), deltaT = state.deltaT();
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if (t < vSmall || deltaT < vSmall)
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{
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return;
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}
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const vector omega = omega_->value(t);
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const vector omegaDot = (omega - omega_->value(t - deltaT))/deltaT;
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const vector theta = omega_->integral(0, t);
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const scalar magTheta = mag(theta);
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const tensor R =
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magTheta > vSmall ? quaternion(theta, magTheta).R() : tensor::I;
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J.X = spatialTransform(R, Zero);
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J.S = Zero;
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J.S1 = Zero;
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J.v = spatialVector(omega, Zero);
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J.c = - spatialVector(omegaDot, Zero);
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}
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// ************************************************************************* //
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114
src/rigidBodyDynamics/joints/rotating/rotating.H
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114
src/rigidBodyDynamics/joints/rotating/rotating.H
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@ -0,0 +1,114 @@
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/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration | Website: https://openfoam.org
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\\ / A nd | Copyright (C) 2018-2022 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
|
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under the terms of the GNU General Public License as published by
|
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the Free Software Foundation, either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
|
||||
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||||
for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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Class
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Foam::RBD::joints::rotating
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Description
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Joint with a specified rotational speed
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Reference:
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\verbatim
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Featherstone, R. (2008).
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Rigid body dynamics algorithms.
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Springer.
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Chapter 4.
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\endverbatim
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SourceFiles
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rotating.C
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\*---------------------------------------------------------------------------*/
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#ifndef RBD_joints_rotating_H
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#define RBD_joints_rotating_H
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#include "joint.H"
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#include "Function1.H"
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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namespace Foam
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{
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namespace RBD
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{
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namespace joints
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{
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/*---------------------------------------------------------------------------*\
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Class rotating Declaration
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\*---------------------------------------------------------------------------*/
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class rotating
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:
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public joint
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{
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private:
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// Private data
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//- Rotation vector function
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autoPtr<Function1<vector>> omega_;
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public:
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//- Runtime type information
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TypeName("rotating");
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// Constructors
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//- Construct for given model from dictionary
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rotating(const rigidBodyModel& model, const dictionary& dict);
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//- Clone this joint
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virtual autoPtr<joint> clone() const;
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//- Destructor
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virtual ~rotating();
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// Member Functions
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//- Update the model state for this joint
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virtual void jcalc
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(
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joint::XSvc& J,
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const rigidBodyModelState& state
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) const;
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};
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace joints
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} // End namespace RBD
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} // End namespace Foam
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#endif
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// ************************************************************************* //
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Reference in New Issue
Block a user