/// Initialization based on passing two vectors (point + dir) on the
/// two bodies, they will represent the X axes of the two frames (Y and Z will
/// be built from the X vector via Gram Schmidt orthonormalization).
/// Use the other ChLinkMateGeneric::Initialize() if you want to set the two frames directly.
public virtual void Initialize(ChBodyFrame mbody1, //< first body to link
ChBodyFrame mbody2, //< second body to link
bool pos_are_relative, //< true: following pos. are relative to bodies.
ChVector mpt1, //< origin of slave frame 1, for 1st body (rel. or abs., see flag above)
ChVector mpt2, //< origin of master frame 2, for 2nd body (rel. or abs., see flag above)
ChVector mnorm1, //< X axis of slave plane, for 1st body (rel. or abs., see flag above)
ChVector mnorm2 //< X axis of master plane, for 2nd body (rel. or abs., see flag above)
)
{
Debug.Assert(mbody1 != mbody2);
this.Body1 = mbody1;
this.Body2 = mbody2;
// this.SetSystem(mbody1.GetSystem());
this.mask.SetTwoBodiesVariables(Body1.Variables(), Body2.Variables());
ChVector mx = new ChVector(0, 0, 0);
ChVector my = new ChVector(0, 0, 0);
ChVector mz = new ChVector(0, 0, 0);
ChVector mN = new ChVector(0, 0, 0);
ChMatrix33 <double> mrot = new ChMatrix33 <double>();
ChFrame <double> mfr1 = new ChFrame <double>();
ChFrame <double> mfr2 = new ChFrame <double>();
if (pos_are_relative)
{
mN = mnorm1;
mN.DirToDxDyDz(ref mx, ref my, ref mz, new ChVector(0, 1, 0));
mrot.Set_A_axis(mx, my, mz);
mfr1.SetRot(mrot);
mfr1.SetPos(mpt1);
mN = mnorm2;
mN.DirToDxDyDz(ref mx, ref my, ref mz, new ChVector(0, 1, 0));
mrot.Set_A_axis(mx, my, mz);
mfr2.SetRot(mrot);
mfr2.SetPos(mpt2);
}
else
{
ChVector temp = ChVector.VECT_Z;
// from abs to body-rel
mN = this.Body1.TransformDirectionParentToLocal(mnorm1);
mN.DirToDxDyDz(ref mx, ref my, ref mz, temp);
mrot.Set_A_axis(mx, my, mz);
mfr1.SetRot(mrot);
mfr1.SetPos(this.Body1.TransformPointParentToLocal(mpt1));
mN = this.Body2.TransformDirectionParentToLocal(mnorm2);
mN.DirToDxDyDz(ref mx, ref my, ref mz, temp);
mrot.Set_A_axis(mx, my, mz);
mfr2.SetRot(mrot);
mfr2.SetPos(this.Body2.TransformPointParentToLocal(mpt2));
}
this.frame1 = mfr1;
this.frame2 = mfr2;
}
// Updates motion laws, marker positions, etc.
public override void UpdateTime(double mytime)
{
// First, inherit to parent class
base.UpdateTime(mytime);
// Move markers 1 and 2 to align them as gear teeth
ChMatrix33 <double> ma1 = new ChMatrix33 <double>(0);
ChMatrix33 <double> ma2 = new ChMatrix33 <double>(0);
ChMatrix33 <double> mrotma = new ChMatrix33 <double>(0);
ChMatrix33 <double> marot_beta = new ChMatrix33 <double>(0);
ChVector mx;
ChVector my;
ChVector mz;
ChVector mr;
ChVector mmark1;
ChVector mmark2;
ChVector lastX;
ChVector vrota;
ChCoordsys newmarkpos = new ChCoordsys(new ChVector(0, 0, 0), new ChQuaternion(1, 0, 0, 0));
ChFrame <double> abs_shaft1 = ChFrame <double> .FNULL; // new ChFrame<double>();
ChFrame <double> abs_shaft2 = ChFrame <double> .FNULL; //new ChFrame<double>();
((ChFrame <double>)Body1).TransformLocalToParent(local_shaft1, abs_shaft1);
((ChFrame <double>)Body2).TransformLocalToParent(local_shaft2, abs_shaft2);
ChVector vbdist = ChVector.Vsub(Get_shaft_pos1(), Get_shaft_pos2());
// ChVector Trad1 = ChVector.Vnorm(ChVector.Vcross(Get_shaft_dir1(), ChVector.Vnorm(ChVector.Vcross(Get_shaft_dir1(), vbdist))));
// ChVector Trad2 = ChVector.Vnorm(ChVector.Vcross(ChVector.Vnorm(ChVector.Vcross(Get_shaft_dir2(), vbdist)), Get_shaft_dir2()));
double dist = ChVector.Vlength(vbdist);
// compute actual rotation of the two wheels (relative to truss).
ChVector md1 = abs_shaft1.GetA().MatrT_x_Vect(-vbdist);
md1.z = 0;
md1 = ChVector.Vnorm(md1);
ChVector md2 = abs_shaft2.GetA().MatrT_x_Vect(-vbdist);
md2.z = 0;
md2 = ChVector.Vnorm(md2);
double periodic_a1 = ChMaths.ChAtan2(md1.x, md1.y);
double periodic_a2 = ChMaths.ChAtan2(md2.x, md2.y);
double old_a1 = a1;
double old_a2 = a2;
double turns_a1 = Math.Floor(old_a1 / ChMaths.CH_C_2PI);
double turns_a2 = Math.Floor(old_a2 / ChMaths.CH_C_2PI);
double a1U = turns_a1 * ChMaths.CH_C_2PI + periodic_a1 + ChMaths.CH_C_2PI;
double a1M = turns_a1 * ChMaths.CH_C_2PI + periodic_a1;
double a1L = turns_a1 * ChMaths.CH_C_2PI + periodic_a1 - ChMaths.CH_C_2PI;
a1 = a1M;
if (Math.Abs(a1U - old_a1) < Math.Abs(a1M - old_a1))
{
a1 = a1U;
}
if (Math.Abs(a1L - a1) < Math.Abs(a1M - a1))
{
a1 = a1L;
}
double a2U = turns_a2 * ChMaths.CH_C_2PI + periodic_a2 + ChMaths.CH_C_2PI;
double a2M = turns_a2 * ChMaths.CH_C_2PI + periodic_a2;
double a2L = turns_a2 * ChMaths.CH_C_2PI + periodic_a2 - ChMaths.CH_C_2PI;
a2 = a2M;
if (Math.Abs(a2U - old_a2) < Math.Abs(a2M - old_a2))
{
a2 = a2U;
}
if (Math.Abs(a2L - a2) < Math.Abs(a2M - a2))
{
a2 = a2L;
}
// compute new markers coordsystem alignment
my = ChVector.Vnorm(vbdist);
mz = Get_shaft_dir1();
mx = ChVector.Vnorm(ChVector.Vcross(my, mz));
mr = ChVector.Vnorm(ChVector.Vcross(mz, mx));
mz = ChVector.Vnorm(ChVector.Vcross(mx, my));
ChVector mz2, mx2, mr2, my2;
my2 = my;
mz2 = Get_shaft_dir2();
mx2 = ChVector.Vnorm(ChVector.Vcross(my2, mz2));
mr2 = ChVector.Vnorm(ChVector.Vcross(mz2, mx2));
ma1.Set_A_axis(mx, my, mz);
// rotate csys because of beta
vrota.x = 0.0;
vrota.y = beta;
vrota.z = 0.0;
mrotma.Set_A_Rxyz(vrota);
marot_beta.nm.matrix.MatrMultiply(ma1.nm.matrix, mrotma.nm.matrix);
// rotate csys because of alpha
vrota.x = 0.0;
vrota.y = 0.0;
vrota.z = alpha;
if (react_force.x < 0)
{
vrota.z = alpha;
}
else
{
vrota.z = -alpha;
}
mrotma.Set_A_Rxyz(vrota);
ma1.nm.matrix.MatrMultiply(marot_beta.nm.matrix, mrotma.nm.matrix);
ma2.nm.matrix.CopyFromMatrix(ma1.nm.matrix);
// is a bevel gear?
double be = Math.Acos(ChVector.Vdot(Get_shaft_dir1(), Get_shaft_dir2()));
bool is_bevel = true;
if (Math.Abs(ChVector.Vdot(Get_shaft_dir1(), Get_shaft_dir2())) > 0.96)
{
is_bevel = false;
}
// compute wheel radii so that:
// w2 = - tau * w1
if (!is_bevel)
{
double pardist = ChVector.Vdot(mr, vbdist);
double inv_tau = 1.0 / tau;
if (!epicyclic)
{
r2 = pardist - pardist / (inv_tau + 1.0);
}
else
{
r2 = pardist - (tau * pardist) / (tau - 1.0);
}
r1 = r2 * tau;
}
else
{
double gamma2;
if (!epicyclic)
{
gamma2 = be / (tau + 1.0);
}
else
{
gamma2 = be / (-tau + 1.0);
}
double al = ChMaths.CH_C_PI - Math.Acos(ChVector.Vdot(Get_shaft_dir2(), my));
double te = ChMaths.CH_C_PI - al - be;
double fd = Math.Sin(te) * (dist / Math.Sin(be));
r2 = fd * Math.Tan(gamma2);
r1 = r2 * tau;
}
// compute markers positions, supposing they
// stay on the ideal wheel contact point
mmark1 = ChVector.Vadd(Get_shaft_pos2(), ChVector.Vmul(mr2, r2));
mmark2 = mmark1;
contact_pt = mmark1;
// correct marker 1 position if phasing is not correct
if (checkphase)
{
double realtau = tau;
if (epicyclic)
{
realtau = -tau;
}
double m_delta;
m_delta = -(a2 / realtau) - a1 - phase;
if (m_delta > ChMaths.CH_C_PI)
{
m_delta -= (ChMaths.CH_C_2PI); // range -180..+180 is better than 0...360
}
if (m_delta > (ChMaths.CH_C_PI / 4.0))
{
m_delta = (ChMaths.CH_C_PI / 4.0); // phase correction only in +/- 45°
}
if (m_delta < -(ChMaths.CH_C_PI / 4.0))
{
m_delta = -(ChMaths.CH_C_PI / 4.0);
}
vrota.x = vrota.y = 0.0;
vrota.z = -m_delta;
mrotma.Set_A_Rxyz(vrota); // rotate about Z of shaft to correct
mmark1 = abs_shaft1.GetA().MatrT_x_Vect(ChVector.Vsub(mmark1, Get_shaft_pos1()));
mmark1 = mrotma.Matr_x_Vect(mmark1);
mmark1 = ChVector.Vadd(abs_shaft1.GetA().Matr_x_Vect(mmark1), Get_shaft_pos1());
}
// Move Shaft 1 along its direction if not aligned to wheel
double offset = ChVector.Vdot(Get_shaft_dir1(), (contact_pt - Get_shaft_pos1()));
ChVector moff = Get_shaft_dir1() * offset;
if (Math.Abs(offset) > 0.0001)
{
local_shaft1.SetPos(local_shaft1.GetPos() + Body1.TransformDirectionParentToLocal(moff));
}
// ! Require that the BDF routine of marker won't handle speed and acc.calculus of the moved marker 2!
marker2.SetMotionType(ChMarker.eChMarkerMotion.M_MOTION_EXTERNAL);
marker1.SetMotionType(ChMarker.eChMarkerMotion.M_MOTION_EXTERNAL);
// move marker1 in proper positions
newmarkpos.pos = mmark1;
newmarkpos.rot = ma1.Get_A_quaternion();
marker1.Impose_Abs_Coord(newmarkpos); // move marker1 into teeth position
// move marker2 in proper positions
newmarkpos.pos = mmark2;
newmarkpos.rot = ma2.Get_A_quaternion();
marker2.Impose_Abs_Coord(newmarkpos); // move marker2 into teeth position
// imposed relative positions/speeds
deltaC.pos = ChVector.VNULL;
deltaC_dt.pos = ChVector.VNULL;
deltaC_dtdt.pos = ChVector.VNULL;
deltaC.rot = ChQuaternion.QUNIT; // no relative rotations imposed!
deltaC_dt.rot = ChQuaternion.QNULL;
deltaC_dtdt.rot = ChQuaternion.QNULL;
}