/*******************************************************************************
-
+
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
********************************************************************************
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
*******************************************************************************/
*******************************************************************************/
-FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex)
+FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex),
+ vUVW(3),
+ vWindUVW(3),
+ vUVWdot(3),
+ vNcg(3),
+ vPQR(3),
+ vForces(3),
+ vEuler(3)
{
Name = "FGTranslation";
- Udot = Vdot = Wdot = 0.0;
+ qbar = 0;
+ Vt = 0.0;
+ Mach = 0.0;
+ alpha = beta = 0.0;
+ rho = 0.002378;
}
+/******************************************************************************/
-FGTranslation::~FGTranslation(void)
-{
-}
+FGTranslation::~FGTranslation(void) {}
+/******************************************************************************/
+
+bool FGTranslation::Run(void) {
+ static FGColumnVector vlastUVWdot(3);
+ static FGMatrix mVel(3,3);
-bool FGTranslation::Run(void)
-{
if (!FGModel::Run()) {
GetState();
- lastUdot = Udot;
- lastVdot = Vdot;
- lastWdot = Wdot;
+ 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;
- Udot = V*R - W*Q + Fx/Mass;
- Vdot = W*P - U*R + Fy/Mass;
- Wdot = U*Q - V*P + Fz/Mass;
-
- U += 0.5*dt*rate*(lastUdot + Udot);
- V += 0.5*dt*rate*(lastVdot + Vdot);
- W += 0.5*dt*rate*(lastWdot + Wdot);
+ qbar = 0.5*rho*Vt*Vt;
- Vt = U*U+V*V+W*W > 0.0 ? sqrt(U*U + V*V + W*W) : 0.0;
+ Mach = Vt / State->Geta();
- if (W != 0.0)
- alpha = U*U > 0.0 ? atan2(W, U) : 0.0;
- if (V != 0.0)
- beta = U*U+W*W > 0.0 ? atan2(V, (fabs(U)/U)*sqrt(U*U + W*W)) : 0.0;
+ vlastUVWdot = vUVWdot;
- qbar = 0.5*rho*Vt*Vt;
+ } else {}
- PutState();
- } else {
- }
return false;
}
+/******************************************************************************/
-void FGTranslation::GetState(void)
-{
+void FGTranslation::GetState(void) {
dt = State->Getdt();
- P = Rotation->GetP();
- Q = Rotation->GetQ();
- R = Rotation->GetR();
-
- Fx = Aircraft->GetFx();
- Fy = Aircraft->GetFy();
- Fz = Aircraft->GetFz();
+ vPQR = Rotation->GetPQR();
+ vForces = Aircraft->GetForces();
Mass = Aircraft->GetMass();
- rho = Atmosphere->Getrho();
+ rho = Atmosphere->GetDensity();
- phi = Rotation->Getphi();
- tht = Rotation->Gettht();
- psi = Rotation->Getpsi();
-}
+ vEuler = Rotation->GetEuler();
-
-void FGTranslation::PutState(void)
-{
- State->SetVt(Vt);
- State->Setqbar(qbar);
+ vWindUVW = Atmosphere->GetWindUVW();
}
projects / flightgear.git / blobdiff