-/*******************************************************************************
-
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
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
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 "FGAuxiliary.h"
#include "FGOutput.h"
-/*******************************************************************************
-************************************ CODE **************************************
-*******************************************************************************/
-
+static const char *IdSrc = "$Header$";
+static const char *IdHdr = ID_TRANSLATION;
-FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex),
- vUVW(3),
- vWindUVW(3),
- vUVWdot(3),
- vPQR(3),
- vForces(3),
- vEuler(3)
-{
- Name = "FGTranslation";
- qbar = 0;
- Vt = 0.0;
- Mach = 0.0;
- alpha = beta = gamma = 0.0;
- rho = 0.002378;
-}
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS IMPLEMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-/******************************************************************************/
-FGTranslation::~FGTranslation(void)
+FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex),
+ vUVW(3),
+ vWindUVW(3),
+ vUVWdot(3),
+ vNcg(3),
+ vPQR(3),
+ vForces(3),
+ vEuler(3)
{
+ Name = "FGTranslation";
+ qbar = 0;
+ Vt = 0.0;
+ Mach = 0.0;
+ alpha = beta = 0.0;
+ adot = bdot = 0.0;
+ rho = 0.002378;
}
-/******************************************************************************/
-
-bool FGTranslation::Run(void)
-{
- static FGColumnVector vlastUVWdot(3);
- static FGMatrix mVel(3,3);
-
- 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;
-
- vUVW += 0.5*dt*rate*(vlastUVWdot + vUVWdot) + vWindUVW;
-
- 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), (fabs(vUVW(eU))/vUVW(eU))*sqrt(vUVW(eU)*vUVW(eU) + vUVW(eW)*vUVW(eW))) : 0.0;
-
- qbar = 0.5*rho*Vt*Vt;
-
- Mach = Vt / State->Geta();
-
- vlastUVWdot = vUVWdot;
-
- } else {
- }
- return false;
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+FGTranslation::~FGTranslation(void) {}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+bool FGTranslation::Run(void) {
+ static FGColumnVector vlastUVWdot(3);
+ static FGMatrix mVel(3,3);
+
+ 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) + vWindUVW;
+
+ 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;
+
+ } else {}
+
+ return false;
}
-/******************************************************************************/
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-void FGTranslation::GetState(void)
-{
+void FGTranslation::GetState(void) {
dt = State->Getdt();
vPQR = Rotation->GetPQR();
vEuler = Rotation->GetEuler();
-// vWindUVW = Atmosphere->GetWindUVW();
+ vWindUVW = Atmosphere->GetWindUVW();
}
projects / flightgear.git / blobdiff