// Get the time derivative from a quaternion, a speed of rotation and an axis, defined in _abs_ coords. ChQuaternion<double> Qdt_from_AngAxis(const ChQuaternion<double>& quat, double angle_dt, const ChVector<double>& axis) { ChVector<double> W; W = Vmul(axis, angle_dt); return Qdt_from_Wabs(W, quat); }
ChQuaternion<double> AngleDTDT_to_QuatDTDT(AngleSet angset, const ChVector<double>& mangles, const ChQuaternion<double>& q) { ChQuaternion<double> res; ChQuaternion<double> qa, qb; ChVector<double> ang0, angA, angB; double hsquared = CH_LOWTOL; ang0 = Quat_to_Angle(angset, q); angA = Vsub(ang0, Vmul(mangles, hsquared)); angB = Vadd(ang0, Vmul(mangles, hsquared)); qa = Angle_to_Quat(angset, angA); qb = Angle_to_Quat(angset, angB); res = Qscale(Qadd(Qadd(qa, qb), Qscale(q, -2)), 1 / hsquared); return res; }
// Get the second time derivative from a quaternion, an angular acceleration and an axis, defined in _abs_ coords. ChQuaternion<double> Qdtdt_from_AngAxis(double angle_dtdt, const ChVector<double>& axis, const ChQuaternion<double>& q, const ChQuaternion<double>& q_dt) { ChVector<double> Acc; Acc = Vmul(axis, angle_dtdt); return Qdtdt_from_Aabs(Acc, q, q_dt); }
ChQuaternion<double> AngleDT_to_QuatDT(AngleSet angset, const ChVector<double>& mangles, const ChQuaternion<double>& q) { ChQuaternion<double> res; ChQuaternion<double> q2; ChVector<double> ang1, ang2; ang1 = Quat_to_Angle(angset, q); ang2 = Vadd(ang1, Vmul(mangles, CH_LOWTOL)); q2 = Angle_to_Quat(angset, ang2); res = Qscale(Qsub(q2, q), (1 / CH_LOWTOL)); return res; }
double ChCollisionUtils::PointTriangleDistance(Vector B, Vector A1, Vector A2, Vector A3, double& mu, double& mv, int& is_into, Vector& Bprojected) { // defaults is_into = 0; mu = mv = -1; double mdistance = 10e22; Vector Dx, Dy, Dz, T1, T1p; Dx = Vsub(A2, A1); Dz = Vsub(A3, A1); Dy = Vcross(Dz, Dx); double dylen = Vlength(Dy); if (fabs(dylen) < EPS_TRIDEGEN) // degenerate triangle return mdistance; Dy = Vmul(Dy, 1.0 / dylen); ChMatrix33<> mA; ChMatrix33<> mAi; mA.Set_A_axis(Dx, Dy, Dz); // invert triangle coordinate matrix -if singular matrix, was degenerate triangle-. if (fabs(mA.FastInvert(mAi)) < 0.000001) return mdistance; T1 = mAi.Matr_x_Vect(Vsub(B, A1)); T1p = T1; T1p.y() = 0; mu = T1.x(); mv = T1.z(); mdistance = -T1.y(); if (mu >= 0 && mv >= 0 && mv <= 1.0 - mu) { is_into = 1; Bprojected = Vadd(A1, mA.Matr_x_Vect(T1p)); } return mdistance; }
void ChLinkSpring::UpdateForces(double mytime) { // Inherit force computation: // also base class can add its own forces. ChLinkMarkers::UpdateForces(mytime); spr_react = 0.0; Vector m_force; double deform = Get_SpringDeform(); spr_react = spr_f * mod_f_time->Get_y(ChTime); spr_react -= (spr_k * mod_k_d->Get_y(deform) * mod_k_speed->Get_y(dist_dt)) * (deform); spr_react -= (spr_r * mod_r_d->Get_y(deform) * mod_r_speed->Get_y(dist_dt)) * (dist_dt); m_force = Vmul(Vnorm(relM.pos), spr_react); C_force = Vadd(C_force, m_force); }
void ChLinkGear::UpdateTime (double mytime) { // First, inherit to parent class ChLinkLock::UpdateTime(mytime); // Move markers 1 and 2 to align them as gear teeth ChMatrix33<> ma1; ChMatrix33<> ma2; ChMatrix33<> mrotma; ChMatrix33<> marot_beta; Vector mx; Vector my; Vector mz; Vector mr; Vector mmark1; Vector mmark2; Vector lastX; Vector vrota; Coordsys newmarkpos; ChFrame<double> abs_shaft1; ChFrame<double> abs_shaft2; ((ChFrame<double>*)Body1)->TrasformLocalToParent(local_shaft1, abs_shaft1); ((ChFrame<double>*)Body2)->TrasformLocalToParent(local_shaft2, abs_shaft2); Vector vbdist = Vsub(Get_shaft_pos1(), Get_shaft_pos2()); Vector Trad1 = Vnorm(Vcross(Get_shaft_dir1(), Vnorm(Vcross(Get_shaft_dir1(),vbdist)))); Vector Trad2 = Vnorm(Vcross(Vnorm(Vcross(Get_shaft_dir2(),vbdist)), Get_shaft_dir2())); double dist = Vlenght(vbdist); // compute actual rotation of the two wheels (relative to truss). Vector md1 = abs_shaft1.GetA()->MatrT_x_Vect(-vbdist); md1.z = 0; md1 = Vnorm (md1); Vector md2 = abs_shaft2.GetA()->MatrT_x_Vect(-vbdist); md2.z = 0; md2 = Vnorm (md2); double periodic_a1 = ChAtan2(md1.x, md1.y); double periodic_a2 = ChAtan2(md2.x, md2.y); double old_a1 = a1; double old_a2 = a2; double turns_a1 = floor (old_a1 / CH_C_2PI); double turns_a2 = floor (old_a2 / CH_C_2PI); double a1U = turns_a1 * CH_C_2PI + periodic_a1 + CH_C_2PI; double a1M = turns_a1 * CH_C_2PI + periodic_a1; double a1L = turns_a1 * CH_C_2PI + periodic_a1 - CH_C_2PI; a1 = a1M; if (fabs(a1U - old_a1) < fabs(a1M - old_a1)) a1 = a1U; if (fabs(a1L - a1) < fabs(a1M - a1)) a1 = a1L; double a2U = turns_a2 * CH_C_2PI + periodic_a2 + CH_C_2PI; double a2M = turns_a2 * CH_C_2PI + periodic_a2; double a2L = turns_a2 * CH_C_2PI + periodic_a2 - CH_C_2PI; a2 = a2M; if (fabs(a2U - old_a2) < fabs(a2M - old_a2)) a2 = a2U; if (fabs(a2L - a2) < fabs(a2M - a2)) a2 = a2L; // compute new markers coordsystem alignment my = Vnorm (vbdist); mz = Get_shaft_dir1(); mx = Vnorm(Vcross (my, mz)); mr = Vnorm(Vcross (mz, mx)); mz = Vnorm(Vcross (mx, my)); ChVector<> mz2, mx2, mr2, my2; my2 = my; mz2 = Get_shaft_dir2(); mx2 = Vnorm(Vcross (my2, mz2)); mr2 = Vnorm(Vcross (mz2, mx2)); ma1.Set_A_axis(mx,my,mz); // rotate csys because of beta vrota.x = 0.0; vrota.y = this->beta; vrota.z = 0.0; mrotma.Set_A_Rxyz(vrota); marot_beta.MatrMultiply(ma1, mrotma); // rotate csys because of alpha vrota.x = 0.0; vrota.y = 0.0; vrota.z = this->alpha; if (react_force.x < 0) vrota.z = this->alpha; else vrota.z = -this->alpha; mrotma.Set_A_Rxyz(vrota); ma1.MatrMultiply(marot_beta, mrotma); ma2.CopyFromMatrix(ma1); // is a bevel gear? double be = acos(Vdot(Get_shaft_dir1(), Get_shaft_dir2())); bool is_bevel= true; if (fabs( 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 = Vdot(mr, vbdist); double inv_tau = 1.0/tau; if (!this->epicyclic) { r2 = pardist - pardist / (inv_tau + 1.0); } else { r2 = pardist - (tau * pardist)/(tau-1.0); } r1 = r2*tau; } else { double gamma2; if (!this->epicyclic) { gamma2 = be/(tau + 1.0); } else { gamma2 = be/(-tau + 1.0); } double al = CH_C_PI - acos (Vdot(Get_shaft_dir2(), my)); double te = CH_C_PI - al - be; double fd = sin(te) * (dist/sin(be)); r2 = fd * tan(gamma2); r1 = r2*tau; } // compute markers positions, supposing they // stay on the ideal wheel contact point mmark1 = Vadd(Get_shaft_pos2(), Vmul(mr2, r2)); mmark2 = mmark1; contact_pt = mmark1; // correct marker 1 position if phasing is not correct if (this->checkphase) { double realtau = tau; if (this->epicyclic) realtau = -tau; double m_delta; m_delta = - (a2/realtau) - a1 - phase; if (m_delta> CH_C_PI) m_delta -= (CH_C_2PI); // range -180..+180 is better than 0...360 if (m_delta> (CH_C_PI/4.0)) m_delta = (CH_C_PI/4.0); // phase correction only in +/- 45° if (m_delta<-(CH_C_PI/4.0)) m_delta =-(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(Vsub(mmark1, Get_shaft_pos1() )); mmark1 = mrotma.Matr_x_Vect(mmark1); mmark1 = Vadd (abs_shaft1.GetA()->Matr_x_Vect(mmark1), Get_shaft_pos1() ); } // Move Shaft 1 along its direction if not aligned to wheel double offset = Vdot (this->Get_shaft_dir1(), (contact_pt - this->Get_shaft_pos1()) ); ChVector<> moff = this->Get_shaft_dir1() * offset; if (fabs (offset) > 0.0001) this->local_shaft1.SetPos( local_shaft1.GetPos() + Body1->Dir_World2Body(&moff) ); // ! Require that the BDF routine of marker won't handle speed and acc.calculus of the moved marker 2! marker2->SetMotionType(ChMarker::M_MOTION_EXTERNAL); marker1->SetMotionType(ChMarker::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 = VNULL; deltaC_dt.pos = VNULL; deltaC_dtdt.pos = VNULL; deltaC.rot = QUNIT; // no relative rotations imposed! deltaC_dt.rot = QNULL; deltaC_dtdt.rot = QNULL; }
void ChLinkBrake::UpdateForces (double mytime) { // First, inherit to parent class ChLinkLock::UpdateForces(mytime); if (this->IsDisabled()) return; // then, if not sticking, if (this->brake_torque) { if (brake_mode == BRAKE_ROTATION) { if ( ((ChLinkMaskLF*)mask)->Constr_E3().IsActive() == false) { int mdir; Vector mv_torque = Vmul(VECT_Z, this->brake_torque); mdir = 0; // clockwise torque if (Vdot(this->relWvel, mv_torque) > 0.0) { mv_torque = Vmul (mv_torque, -1.0); // keep torque always opposed to ang speed. mdir = 1; // counterclockwise torque } if (mdir != this->last_dir) this->must_stick = TRUE; this->last_dir = mdir; // +++ADD TO LINK TORQUE VECTOR C_torque = Vadd(C_torque, mv_torque); } } if (brake_mode == BRAKE_TRANSLATEX) { if ( ((ChLinkMaskLF*)mask)->Constr_X().IsActive() == false) { int mdir; Vector mv_force = Vmul(VECT_X, this->brake_torque); mdir = 0; // F--> rear motion: frontfacing break force if (this->relM_dt.pos.x > 0.0) { mv_force = Vmul (mv_force, -1.0); // break force always opposed to speed mdir = 1; // F<-- backfacing breakforce for front motion } if (mdir != this->last_dir) this->must_stick = TRUE; this->last_dir = mdir; // +++ADD TO LINK TORQUE VECTOR C_force = Vadd(C_force, mv_force); } } } // turn off sticking feature if stick ration not > 1.0 if (this->stick_ratio <= 1.0) must_stick = FALSE; }