146 lines
4.2 KiB
C++
146 lines
4.2 KiB
C++
/*******************************************************************************
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Module: FGTranslation.cpp
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Author: Jon Berndt
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Date started: 12/02/98
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Purpose: Integrates the translational EOM
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Called by: FDMExec
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------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program 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 FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA.
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Further information about the GNU General Public License can also be found on
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the world wide web at http://www.gnu.org.
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FUNCTIONAL DESCRIPTION
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--------------------------------------------------------------------------------
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This class integrates the translational EOM.
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HISTORY
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--------------------------------------------------------------------------------
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12/02/98 JSB Created
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********************************************************************************
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COMMENTS, REFERENCES, and NOTES
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********************************************************************************
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[1] Cooke, Zyda, Pratt, and McGhee, "NPSNET: Flight Simulation Dynamic Modeling
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Using Quaternions", Presence, Vol. 1, No. 4, pp. 404-420 Naval Postgraduate
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School, January 1994
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[2] D. M. Henderson, "Euler Angles, Quaternions, and Transformation Matrices",
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JSC 12960, July 1977
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[3] Richard E. McFarland, "A Standard Kinematic Model for Flight Simulation at
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NASA-Ames", NASA CR-2497, January 1975
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[4] Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics",
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Wiley & Sons, 1979 ISBN 0-471-03032-5
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[5] Bernard Etkin, "Dynamics of Flight, Stability and Control", Wiley & Sons,
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1982 ISBN 0-471-08936-2
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The order of rotations used in this class corresponds to a 3-2-1 sequence,
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or Y-P-R, or Z-Y-X, if you prefer.
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********************************************************************************
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INCLUDES
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*******************************************************************************/
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#include "FGTranslation.h"
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#include "FGRotation.h"
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#include "FGAtmosphere.h"
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#include "FGState.h"
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#include "FGFDMExec.h"
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#include "FGFCS.h"
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#include "FGAircraft.h"
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#include "FGPosition.h"
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#include "FGAuxiliary.h"
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#include "FGOutput.h"
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/*******************************************************************************
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************************************ CODE **************************************
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*******************************************************************************/
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FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex)
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{
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Name = "FGTranslation";
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Udot = Vdot = Wdot = 0.0;
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}
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FGTranslation::~FGTranslation(void)
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{
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}
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bool FGTranslation::Run(void)
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{
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if (!FGModel::Run()) {
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GetState();
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lastUdot = Udot;
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lastVdot = Vdot;
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lastWdot = Wdot;
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Udot = V*R - W*Q + Fx/Mass;
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Vdot = W*P - U*R + Fy/Mass;
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Wdot = U*Q - V*P + Fz/Mass;
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U += 0.5*dt*rate*(lastUdot + Udot);
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V += 0.5*dt*rate*(lastVdot + Vdot);
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W += 0.5*dt*rate*(lastWdot + Wdot);
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Vt = U*U+V*V+W*W > 0.0 ? sqrt(U*U + V*V + W*W) : 0.0;
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if (W != 0.0)
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alpha = U*U > 0.0 ? atan2(W, U) : 0.0;
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if (V != 0.0)
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beta = U*U+W*W > 0.0 ? atan2(V, (fabs(U)/U)*sqrt(U*U + W*W)) : 0.0;
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qbar = 0.5*rho*Vt*Vt;
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PutState();
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} else {
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}
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return false;
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}
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void FGTranslation::GetState(void)
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{
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dt = State->Getdt();
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P = Rotation->GetP();
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Q = Rotation->GetQ();
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R = Rotation->GetR();
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Fx = Aircraft->GetFx();
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Fy = Aircraft->GetFy();
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Fz = Aircraft->GetFz();
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Mass = Aircraft->GetMass();
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rho = Atmosphere->Getrho();
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phi = Rotation->Getphi();
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tht = Rotation->Gettht();
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psi = Rotation->Getpsi();
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}
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void FGTranslation::PutState(void)
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{
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State->SetVt(Vt);
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State->Setqbar(qbar);
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}
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