src/FDM/JSBSim/FGTranslation.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGTranslation.cpp
   4  Author:       Jon Berndt
   5  Date started: 12/02/98
   6  Purpose:      Integrates the translational EOM
   7  Called by:    FDMExec
   8
   9  ------------- Copyright (C) 1999  Jon S. Berndt (jsb@hal-pc.org) -------------
  10
  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
  14  version.
  15
  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
  19  details.
  20
  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.
  24
  25  Further information about the GNU General Public License can also be found on
  26  the world wide web at http://www.gnu.org.
  27
  28 FUNCTIONAL DESCRIPTION
  29 --------------------------------------------------------------------------------
  30 This class integrates the translational EOM.
  31
  32 HISTORY
  33 --------------------------------------------------------------------------------
  34 12/02/98   JSB   Created
  35  7/23/99   TP    Added data member and modified Run and PutState to calcuate
  36                  Mach number
  37
  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
  43     School, January 1994
  44 [2] D. M. Henderson, "Euler Angles, Quaternions, and Transformation Matrices",
  45     JSC 12960, July 1977
  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
  52
  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.
  55
  56 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  57 INCLUDES
  58 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  59
  60 #include "FGTranslation.h"
  61 #include "FGRotation.h"
  62 #include "FGAtmosphere.h"
  63 #include "FGState.h"
  64 #include "FGFDMExec.h"
  65 #include "FGFCS.h"
  66 #include "FGMassBalance.h"
  67 #include "FGAircraft.h"
  68 #include "FGPosition.h"
  69 #include "FGAuxiliary.h"
  70 #include "FGOutput.h"
  71 #include "FGPropertyManager.h"
  72
  73 static const char *IdSrc = "$Id$";
  74 static const char *IdHdr = ID_TRANSLATION;
  75
  76 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  77 CLASS IMPLEMENTATION
  78 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  79
  80
  81 FGTranslation::FGTranslation(FGFDMExec* fdmex) : FGModel(fdmex)
  82 {
  83   Name = "FGTranslation";
  84   qbar = 0;
  85   qbarUW = 0.0;
  86   qbarUV = 0.0;
  87   Vt = 0.0;
  88   Mach = 0.0;
  89   alpha = beta = 0.0;
  90   adot = bdot = 0.0;
  91
  92   vUVWdot.InitMatrix();
  93   vUVWdot_prev[0].InitMatrix();
  94   vUVWdot_prev[1].InitMatrix();
  95   vUVWdot_prev[2].InitMatrix();
  96
  97   bind();
  98   Debug(0);
  99 }
 100
 101 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 102
 103 FGTranslation::~FGTranslation(void)
 104 {
 105   unbind();
 106   Debug(1);
 107 }
 108
 109 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 110
 111 bool FGTranslation::Run(void)
 112 {
 113   if (!FGModel::Run()) {
 114
 115     mVel(1,1) =  0.0;
 116     mVel(1,2) = -vUVW(eW);
 117     mVel(1,3) =  vUVW(eV);
 118     mVel(2,1) =  vUVW(eW);
 119     mVel(2,2) =  0.0;
 120     mVel(2,3) = -vUVW(eU);
 121     mVel(3,1) = -vUVW(eV);
 122     mVel(3,2) =  vUVW(eU);
 123     mVel(3,3) =  0.0;
 124
 125     vUVWdot = mVel*Rotation->GetPQR() + Aircraft->GetBodyAccel();
 126
 127     vUVW += State->Integrate(FGState::TRAPZ, State->Getdt()*rate, vUVWdot, vUVWdot_prev);
 128
 129     vAeroUVW = vUVW + State->GetTl2b()*Atmosphere->GetWindNED();
 130
 131     Vt = vAeroUVW.Magnitude();
 132     if ( Vt > 1) {
 133       if (vAeroUVW(eW) != 0.0)
 134         alpha = vAeroUVW(eU)*vAeroUVW(eU) > 0.0 ? atan2(vAeroUVW(eW), vAeroUVW(eU)) : 0.0;
 135       if (vAeroUVW(eV) != 0.0)
 136         beta = vAeroUVW(eU)*vAeroUVW(eU)+vAeroUVW(eW)*vAeroUVW(eW) > 0.0 ? atan2(vAeroUVW(eV),
 137                sqrt(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW))) : 0.0;
 138
 139       // stolen, quite shamelessly, from LaRCsim
 140       double mUW = (vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW));
 141       double signU=1;
 142       if (vAeroUVW(eU) != 0.0)
 143         signU = vAeroUVW(eU)/fabs(vAeroUVW(eU));
 144
 145       if ( (mUW == 0.0) || (Vt == 0.0) ) {
 146         adot = 0.0;
 147         bdot = 0.0;
 148       } else {
 149         adot = (vAeroUVW(eU)*vAeroUVW(eW) - vAeroUVW(eW)*vUVWdot(eU))/mUW;
 150         bdot = (signU*mUW*vUVWdot(eV) - vAeroUVW(eV)*(vAeroUVW(eU)*vUVWdot(eU)
 151                 + vAeroUVW(eW)*vUVWdot(eW)))/(Vt*Vt*sqrt(mUW));
 152       }
 153     } else {
 154       alpha = beta = adot = bdot = 0;
 155     }
 156
 157     qbar = 0.5*Atmosphere->GetDensity()*Vt*Vt;
 158     qbarUW = 0.5*Atmosphere->GetDensity()*(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW));
 159     qbarUV = 0.5*Atmosphere->GetDensity()*(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eV)*vAeroUVW(eV));
 160     Mach = Vt / State->Geta();
 161
 162     if (debug_lvl > 1) Debug(1);
 163
 164     return false;
 165   } else {
 166     return true;
 167   }
 168 }
 169
 170 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 171
 172 void FGTranslation::bind(void)
 173 {
 174   typedef double (FGTranslation::*PMF)(int) const;
 175   PropertyManager->Tie("velocities/u-fps", this,1,
 176                        (PMF)&FGTranslation::GetUVW /*,
 177                        &FGTranslation::SetUVW,
 178                        true */);
 179   PropertyManager->Tie("velocities/v-fps", this,2,
 180                        (PMF)&FGTranslation::GetUVW /*,
 181                        &FGTranslation::SetUVW,
 182                        true*/);
 183   PropertyManager->Tie("velocities/w-fps", this,3,
 184                        (PMF)&FGTranslation::GetUVW /*,
 185                        &FGTranslation::SetUVW,
 186                        true*/);
 187   PropertyManager->Tie("accelerations/udot-fps", this,1,
 188                        (PMF)&FGTranslation::GetUVWdot);
 189   PropertyManager->Tie("accelerations/vdot-fps", this,2,
 190                        (PMF)&FGTranslation::GetUVWdot);
 191   PropertyManager->Tie("accelerations/wdot-fps", this,3,
 192                        (PMF)&FGTranslation::GetUVWdot);
 193   PropertyManager->Tie("velocities/u-aero-fps", this,1,
 194                        (PMF)&FGTranslation::GetAeroUVW);
 195   PropertyManager->Tie("velocities/v-aero-fps", this,2,
 196                        (PMF)&FGTranslation::GetAeroUVW);
 197   PropertyManager->Tie("velocities/w-aero-fps", this,3,
 198                        (PMF)&FGTranslation::GetAeroUVW);
 199   PropertyManager->Tie("aero/alpha-rad", this,
 200                        &FGTranslation::Getalpha,
 201                        &FGTranslation::Setalpha,
 202                        true);
 203   PropertyManager->Tie("aero/beta-rad", this,
 204                        &FGTranslation::Getbeta,
 205                        &FGTranslation::Setbeta,
 206                        true);
 207   PropertyManager->Tie("aero/mag-beta-rad", this,
 208                        &FGTranslation::GetMagBeta);
 209   PropertyManager->Tie("aero/qbar-psf", this,
 210                        &FGTranslation::Getqbar,
 211                        &FGTranslation::Setqbar,
 212                        true);
 213   PropertyManager->Tie("aero/qbarUW-psf", this,
 214                        &FGTranslation::GetqbarUW,
 215                        &FGTranslation::SetqbarUW,
 216                        true);
 217   PropertyManager->Tie("aero/qbarUV-psf", this,
 218                        &FGTranslation::GetqbarUV,
 219                        &FGTranslation::SetqbarUV,
 220                        true);
 221   PropertyManager->Tie("velocities/vt-fps", this,
 222                        &FGTranslation::GetVt,
 223                        &FGTranslation::SetVt,
 224                        true);
 225   PropertyManager->Tie("velocities/mach-norm", this,
 226                        &FGTranslation::GetMach,
 227                        &FGTranslation::SetMach,
 228                        true);
 229   PropertyManager->Tie("aero/alphadot-rad_sec", this,
 230                        &FGTranslation::Getadot,
 231                        &FGTranslation::Setadot,
 232                        true);
 233   PropertyManager->Tie("aero/betadot-rad_sec", this,
 234                        &FGTranslation::Getbdot,
 235                        &FGTranslation::Setbdot,
 236                        true);
 237 }
 238
 239 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 240
 241 void FGTranslation::unbind(void)
 242 {
 243   PropertyManager->Untie("velocities/u-fps");
 244   PropertyManager->Untie("velocities/v-fps");
 245   PropertyManager->Untie("velocities/w-fps");
 246   PropertyManager->Untie("accelerations/udot-fps");
 247   PropertyManager->Untie("accelerations/vdot-fps");
 248   PropertyManager->Untie("accelerations/wdot-fps");
 249   PropertyManager->Untie("velocities/u-aero-fps");
 250   PropertyManager->Untie("velocities/v-aero-fps");
 251   PropertyManager->Untie("velocities/w-aero-fps");
 252   PropertyManager->Untie("aero/alpha-rad");
 253   PropertyManager->Untie("aero/beta-rad");
 254   PropertyManager->Untie("aero/qbar-psf");
 255   PropertyManager->Untie("aero/qbarUW-psf");
 256   PropertyManager->Untie("aero/qbarUV-psf");
 257   PropertyManager->Untie("velocities/vt-fps");
 258   PropertyManager->Untie("velocities/mach-norm");
 259   PropertyManager->Untie("aero/alphadot-rad_sec");
 260   PropertyManager->Untie("aero/betadot-rad_sec");
 261 }
 262
 263 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 264 //    The bitmasked value choices are as follows:
 265 //    unset: In this case (the default) JSBSim would only print
 266 //       out the normally expected messages, essentially echoing
 267 //       the config files as they are read. If the environment
 268 //       variable is not set, debug_lvl is set to 1 internally
 269 //    0: This requests JSBSim not to output any messages
 270 //       whatsoever.
 271 //    1: This value explicity requests the normal JSBSim
 272 //       startup messages
 273 //    2: This value asks for a message to be printed out when
 274 //       a class is instantiated
 275 //    4: When this value is set, a message is displayed when a
 276 //       FGModel object executes its Run() method
 277 //    8: When this value is set, various runtime state variables
 278 //       are printed out periodically
 279 //    16: When set various parameters are sanity checked and
 280 //       a message is printed out when they go out of bounds
 281
 282 void FGTranslation::Debug(int from)
 283 {
 284   if (debug_lvl <= 0) return;
 285
 286   if (debug_lvl & 1) { // Standard console startup message output
 287     if (from == 0) { // Constructor
 288
 289     }
 290   }
 291   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 292     if (from == 0) cout << "Instantiated: FGTranslation" << endl;
 293     if (from == 1) cout << "Destroyed:    FGTranslation" << endl;
 294   }
 295   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 296   }
 297   if (debug_lvl & 8 ) { // Runtime state variables
 298   }
 299   if (debug_lvl & 16) { // Sanity checking
 300     if (fabs(vUVW(eU)) > 1e6)
 301       cout << "FGTranslation::U velocity out of bounds: " << vUVW(eU) << endl;
 302     if (fabs(vUVW(eV)) > 1e6)
 303       cout << "FGTranslation::V velocity out of bounds: " << vUVW(eV) << endl;
 304     if (fabs(vUVW(eW)) > 1e6)
 305       cout << "FGTranslation::W velocity out of bounds: " << vUVW(eW) << endl;
 306     if (fabs(vUVWdot(eU)) > 1e4)
 307       cout << "FGTranslation::U acceleration out of bounds: " << vUVWdot(eU) << endl;
 308     if (fabs(vUVWdot(eV)) > 1e4)
 309       cout << "FGTranslation::V acceleration out of bounds: " << vUVWdot(eV) << endl;
 310     if (fabs(vUVWdot(eW)) > 1e4)
 311       cout << "FGTranslation::W acceleration out of bounds: " << vUVWdot(eW) << endl;
 312     if (Mach > 100 || Mach < 0.00)
 313       cout << "FGTranslation::Mach is out of bounds: " << Mach << endl;
 314     if (qbar > 1e6 || qbar < 0.00)
 315       cout << "FGTranslation::qbar is out of bounds: " << qbar << endl;
 316   }
 317   if (debug_lvl & 64) {
 318     if (from == 0) { // Constructor
 319       cout << IdSrc << endl;
 320       cout << IdHdr << endl;
 321     }
 322   }
 323 }
 324