/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Module: FGTranslation.cpp Author: Jon Berndt Date started: 12/02/98 Purpose: Integrates the translational EOM Called by: FDMExec ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) ------------- This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Further information about the GNU General Public License can also be found on the world wide web at http://www.gnu.org. FUNCTIONAL DESCRIPTION -------------------------------------------------------------------------------- This class integrates the translational EOM. HISTORY -------------------------------------------------------------------------------- 12/02/98 JSB Created 7/23/99 TP Added data member and modified Run and PutState to calcuate Mach number %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% COMMENTS, REFERENCES, and NOTES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [1] Cooke, Zyda, Pratt, and McGhee, "NPSNET: Flight Simulation Dynamic Modeling Using Quaternions", Presence, Vol. 1, No. 4, pp. 404-420 Naval Postgraduate School, January 1994 [2] D. M. Henderson, "Euler Angles, Quaternions, and Transformation Matrices", JSC 12960, July 1977 [3] Richard E. McFarland, "A Standard Kinematic Model for Flight Simulation at NASA-Ames", NASA CR-2497, January 1975 [4] Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics", Wiley & Sons, 1979 ISBN 0-471-03032-5 [5] Bernard Etkin, "Dynamics of Flight, Stability and Control", Wiley & Sons, 1982 ISBN 0-471-08936-2 The order of rotations used in this class corresponds to a 3-2-1 sequence, or Y-P-R, or Z-Y-X, if you prefer. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% INCLUDES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/ #include "FGTranslation.h" #include "FGRotation.h" #include "FGAtmosphere.h" #include "FGState.h" #include "FGFDMExec.h" #include "FGFCS.h" #include "FGMassBalance.h" #include "FGAircraft.h" #include "FGPosition.h" #include "FGAuxiliary.h" #include "FGOutput.h" static const char *IdSrc = "$Id$"; static const char *IdHdr = ID_TRANSLATION; extern short debug_lvl; /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% CLASS IMPLEMENTATION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/ FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex), vUVW(3), vUVWdot(3), vNcg(3), vPQR(3), vForces(3), vEuler(3), vlastUVWdot(3), mVel(3,3) { Name = "FGTranslation"; qbar = 0; Vt = 0.0; Mach = 0.0; alpha = beta = 0.0; adot = bdot = 0.0; rho = 0.002378; if (debug_lvl & 2) cout << "Instantiated: " << Name << endl; } //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% FGTranslation::~FGTranslation() { if (debug_lvl & 2) cout << "Destroyed: FGTranslation" << endl; } //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% bool FGTranslation::Run(void) { if (!FGModel::Run()) { GetState(); mVel(1,1) = 0.0; mVel(1,2) = -vUVW(eW); mVel(1,3) = vUVW(eV); mVel(2,1) = vUVW(eW); mVel(2,2) = 0.0; mVel(2,3) = -vUVW(eU); mVel(3,1) = -vUVW(eV); mVel(3,2) = vUVW(eU); mVel(3,3) = 0.0; vUVWdot = mVel*vPQR + vForces/Mass; vNcg = vUVWdot*INVGRAVITY; vUVW += 0.5*dt*rate*(vlastUVWdot + vUVWdot); Vt = vUVW.Magnitude(); if (vUVW(eW) != 0.0) alpha = vUVW(eU)*vUVW(eU) > 0.0 ? atan2(vUVW(eW), vUVW(eU)) : 0.0; if (vUVW(eV) != 0.0) beta = vUVW(eU)*vUVW(eU)+vUVW(eW)*vUVW(eW) > 0.0 ? atan2(vUVW(eV), sqrt(vUVW(eU)*vUVW(eU) + vUVW(eW)*vUVW(eW))) : 0.0; // stolen, quite shamelessly, from LaRCsim float mUW = (vUVW(eU)*vUVW(eU) + vUVW(eW)*vUVW(eW)); float signU=1; if (vUVW(eU) != 0.0) signU = vUVW(eU)/fabs(vUVW(eU)); if ( (mUW == 0.0) || (Vt == 0.0) ) { adot = 0.0; bdot = 0.0; } else { adot = (vUVW(eU)*vUVWdot(eW) - vUVW(eW)*vUVWdot(eU))/mUW; bdot = (signU*mUW*vUVWdot(eV) - vUVW(eV)*(vUVW(eU)*vUVWdot(eU) + vUVW(eW)*vUVWdot(eW)))/(Vt*Vt*sqrt(mUW)); } qbar = 0.5*rho*Vt*Vt; Mach = Vt / State->Geta(); vlastUVWdot = vUVWdot; if (debug_lvl > 1) Debug(); return false; } else { return true; } } //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% void FGTranslation::GetState(void) { dt = State->Getdt(); vPQR = Rotation->GetPQR(); vForces = Aircraft->GetForces(); Mass = MassBalance->GetMass(); rho = Atmosphere->GetDensity(); vEuler = Rotation->GetEuler(); } //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% void FGTranslation::Debug(void) { if (debug_lvl & 16) { // Sanity check variables if (fabs(vUVW(eU)) > 1e6) cout << "FGTranslation::U velocity out of bounds: " << vUVW(eU) << endl; if (fabs(vUVW(eV)) > 1e6) cout << "FGTranslation::V velocity out of bounds: " << vUVW(eV) << endl; if (fabs(vUVW(eW)) > 1e6) cout << "FGTranslation::W velocity out of bounds: " << vUVW(eW) << endl; if (fabs(vUVWdot(eU)) > 1e4) cout << "FGTranslation::U acceleration out of bounds: " << vUVWdot(eU) << endl; if (fabs(vUVWdot(eV)) > 1e4) cout << "FGTranslation::V acceleration out of bounds: " << vUVWdot(eV) << endl; if (fabs(vUVWdot(eW)) > 1e4) cout << "FGTranslation::W acceleration out of bounds: " << vUVWdot(eW) << endl; if (Mach > 100 || Mach < 0.00) cout << "FGTranslation::Mach is out of bounds: " << Mach << endl; if (qbar > 1e6 || qbar < 0.00) cout << "FGTranslation::qbar is out of bounds: " << qbar << endl; } }