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 "FGMassBalance.h"
67 #include "FGAircraft.h"
68 #include "FGPosition.h"
69 #include "FGAuxiliary.h"
72 static const char *IdSrc = "$Id$";
73 static const char *IdHdr = ID_TRANSLATION;
75 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
77 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
80 FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex),
87 Name = "FGTranslation";
94 if (debug_lvl & 2) cout << "Instantiated: " << Name << endl;
97 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
99 FGTranslation::~FGTranslation()
101 if (debug_lvl & 2) cout << "Destroyed: FGTranslation" << endl;
104 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
106 bool FGTranslation::Run(void)
108 double Tc = 0.5*State->Getdt()*rate;
110 if (!FGModel::Run()) {
113 mVel(1,2) = -vUVW(eW);
114 mVel(1,3) = vUVW(eV);
115 mVel(2,1) = vUVW(eW);
117 mVel(2,3) = -vUVW(eU);
118 mVel(3,1) = -vUVW(eV);
119 mVel(3,2) = vUVW(eU);
122 vUVWdot = mVel*Rotation->GetPQR() + Aircraft->GetBodyAccel();
124 vUVW += Tc * (vlastUVWdot + vUVWdot);
125 vAero = vUVW + State->GetTl2b()*Atmosphere->GetWindNED();
127 Vt = vAero.Magnitude();
129 if (vAero(eW) != 0.0)
130 alpha = vAero(eU)*vAero(eU) > 0.0 ? atan2(vAero(eW), vAero(eU)) : 0.0;
131 if (vAero(eV) != 0.0)
132 beta = vAero(eU)*vAero(eU)+vAero(eW)*vAero(eW) > 0.0 ? atan2(vAero(eV),
133 sqrt(vAero(eU)*vAero(eU) + vAero(eW)*vAero(eW))) : 0.0;
135 // stolen, quite shamelessly, from LaRCsim
136 double mUW = (vAero(eU)*vAero(eU) + vAero(eW)*vAero(eW));
138 if (vAero(eU) != 0.0)
139 signU = vAero(eU)/fabs(vAero(eU));
141 if ( (mUW == 0.0) || (Vt == 0.0) ) {
145 adot = (vAero(eU)*vAero(eW) - vAero(eW)*vUVWdot(eU))/mUW;
146 bdot = (signU*mUW*vUVWdot(eV) - vAero(eV)*(vAero(eU)*vUVWdot(eU)
147 + vAero(eW)*vUVWdot(eW)))/(Vt*Vt*sqrt(mUW));
150 alpha = beta = adot = bdot = 0;
153 qbar = 0.5*Atmosphere->GetDensity()*Vt*Vt;
154 Mach = Vt / State->Geta();
156 vlastUVWdot = vUVWdot;
158 if (debug_lvl > 1) Debug();
166 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
168 void FGTranslation::Debug(void)
170 if (debug_lvl & 16) { // Sanity check variables
171 if (fabs(vUVW(eU)) > 1e6)
172 cout << "FGTranslation::U velocity out of bounds: " << vUVW(eU) << endl;
173 if (fabs(vUVW(eV)) > 1e6)
174 cout << "FGTranslation::V velocity out of bounds: " << vUVW(eV) << endl;
175 if (fabs(vUVW(eW)) > 1e6)
176 cout << "FGTranslation::W velocity out of bounds: " << vUVW(eW) << endl;
177 if (fabs(vUVWdot(eU)) > 1e4)
178 cout << "FGTranslation::U acceleration out of bounds: " << vUVWdot(eU) << endl;
179 if (fabs(vUVWdot(eV)) > 1e4)
180 cout << "FGTranslation::V acceleration out of bounds: " << vUVWdot(eV) << endl;
181 if (fabs(vUVWdot(eW)) > 1e4)
182 cout << "FGTranslation::W acceleration out of bounds: " << vUVWdot(eW) << endl;
183 if (Mach > 100 || Mach < 0.00)
184 cout << "FGTranslation::Mach is out of bounds: " << Mach << endl;
185 if (qbar > 1e6 || qbar < 0.00)
186 cout << "FGTranslation::qbar is out of bounds: " << qbar << endl;