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flightgear/src/FDM/JSBSim/FGTranslation.cpp
curt 71a562b695 Sync with latest JSBSim changes.
2001-11-30 17:49:37 +00:00

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex),
vUVW(3),
vUVWdot(3),
vlastUVWdot(3),
mVel(3,3),
vAeroUVW(3)
{
Name = "FGTranslation";
qbar = 0;
Vt = 0.0;
Mach = 0.0;
alpha = beta = 0.0;
adot = bdot = 0.0;
if (debug_lvl & 2) cout << "Instantiated: " << Name << endl;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGTranslation::~FGTranslation()
{
if (debug_lvl & 2) cout << "Destroyed: FGTranslation" << endl;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGTranslation::Run(void)
{
double Tc = 0.5*State->Getdt()*rate;
if (!FGModel::Run()) {
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*Rotation->GetPQR() + Aircraft->GetBodyAccel();
vUVW += Tc * (vlastUVWdot + vUVWdot);
vAeroUVW = vUVW + State->GetTl2b()*Atmosphere->GetWindNED();
Vt = vAeroUVW.Magnitude();
if ( Vt > 1) {
if (vAeroUVW(eW) != 0.0)
alpha = vAeroUVW(eU)*vAeroUVW(eU) > 0.0 ? atan2(vAeroUVW(eW), vAeroUVW(eU)) : 0.0;
if (vAeroUVW(eV) != 0.0)
beta = vAeroUVW(eU)*vAeroUVW(eU)+vAeroUVW(eW)*vAeroUVW(eW) > 0.0 ? atan2(vAeroUVW(eV),
sqrt(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW))) : 0.0;
// stolen, quite shamelessly, from LaRCsim
double mUW = (vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW));
double signU=1;
if (vAeroUVW(eU) != 0.0)
signU = vAeroUVW(eU)/fabs(vAeroUVW(eU));
if ( (mUW == 0.0) || (Vt == 0.0) ) {
adot = 0.0;
bdot = 0.0;
} else {
adot = (vAeroUVW(eU)*vAeroUVW(eW) - vAeroUVW(eW)*vUVWdot(eU))/mUW;
bdot = (signU*mUW*vUVWdot(eV) - vAeroUVW(eV)*(vAeroUVW(eU)*vUVWdot(eU)
+ vAeroUVW(eW)*vUVWdot(eW)))/(Vt*Vt*sqrt(mUW));
}
} else {
alpha = beta = adot = bdot = 0;
}
qbar = 0.5*Atmosphere->GetDensity()*Vt*Vt;
Mach = Vt / State->Geta();
vlastUVWdot = vUVWdot;
if (debug_lvl > 1) Debug();
return false;
} else {
return true;
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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;
}
}
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