1 /*******************************************************************************
3 Module: FGTranslation.cpp
6 Purpose: Integrates the translational EOM
9 ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
11 This program is free software; you can redistribute it and/or modify it under
12 the terms of the GNU General Public License as published by the Free Software
13 Foundation; either version 2 of the License, or (at your option) any later
16 This program is distributed in the hope that it will be useful, but WITHOUT
17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
21 You should have received a copy of the GNU General Public License along with
22 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
23 Place - Suite 330, Boston, MA 02111-1307, USA.
25 Further information about the GNU General Public License can also be found on
26 the world wide web at http://www.gnu.org.
28 FUNCTIONAL DESCRIPTION
29 --------------------------------------------------------------------------------
30 This class integrates the translational EOM.
33 --------------------------------------------------------------------------------
35 7/23/99 TP Added data member and modified Run and PutState to calcuate
38 ********************************************************************************
39 COMMENTS, REFERENCES, and NOTES
40 ********************************************************************************
41 [1] Cooke, Zyda, Pratt, and McGhee, "NPSNET: Flight Simulation Dynamic Modeling
42 Using Quaternions", Presence, Vol. 1, No. 4, pp. 404-420 Naval Postgraduate
44 [2] D. M. Henderson, "Euler Angles, Quaternions, and Transformation Matrices",
46 [3] Richard E. McFarland, "A Standard Kinematic Model for Flight Simulation at
47 NASA-Ames", NASA CR-2497, January 1975
48 [4] Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics",
49 Wiley & Sons, 1979 ISBN 0-471-03032-5
50 [5] Bernard Etkin, "Dynamics of Flight, Stability and Control", Wiley & Sons,
51 1982 ISBN 0-471-08936-2
53 The order of rotations used in this class corresponds to a 3-2-1 sequence,
54 or Y-P-R, or Z-Y-X, if you prefer.
56 ********************************************************************************
58 *******************************************************************************/
60 #include "FGTranslation.h"
61 #include "FGRotation.h"
62 #include "FGAtmosphere.h"
64 #include "FGFDMExec.h"
66 #include "FGAircraft.h"
67 #include "FGPosition.h"
68 #include "FGAuxiliary.h"
71 /*******************************************************************************
72 ************************************ CODE **************************************
73 *******************************************************************************/
76 FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex)
78 Name = "FGTranslation";
79 Udot = Vdot = Wdot = 0.0;
83 FGTranslation::~FGTranslation(void)
88 bool FGTranslation::Run(void)
90 if (!FGModel::Run()) {
98 Udot = V*R - W*Q + Fx/Mass;
99 Vdot = W*P - U*R + Fy/Mass;
100 Wdot = U*Q - V*P + Fz/Mass;
102 U += 0.5*dt*rate*(lastUdot + Udot);
103 V += 0.5*dt*rate*(lastVdot + Vdot);
104 W += 0.5*dt*rate*(lastWdot + Wdot);
106 Vt = U*U+V*V+W*W > 0.0 ? sqrt(U*U + V*V + W*W) : 0.0;
109 alpha = U*U > 0.0 ? atan2(W, U) : 0.0;
111 beta = U*U+W*W > 0.0 ? atan2(V, (fabs(U)/U)*sqrt(U*U + W*W)) : 0.0;
113 qbar = 0.5*rho*Vt*Vt;
115 mach = Vt / State->Geta();
124 void FGTranslation::GetState(void)
128 P = Rotation->GetP();
129 Q = Rotation->GetQ();
130 R = Rotation->GetR();
132 Fx = Aircraft->GetFx();
133 Fy = Aircraft->GetFy();
134 Fz = Aircraft->GetFz();
136 Mass = Aircraft->GetMass();
137 rho = Atmosphere->GetDensity();
139 phi = Rotation->Getphi();
140 tht = Rotation->Gettht();
141 psi = Rotation->Getpsi();
145 void FGTranslation::PutState(void)
148 State->Setqbar(qbar);
149 State->SetMach(mach);