src/FDM/JSBSim/FGAerodynamics.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGAerodynamics.cpp
   4  Author:       Jon S. Berndt
   5  Date started: 09/13/00
   6  Purpose:      Encapsulates the aerodynamic forces (gear and collision)
   7
   8  ------------- Copyright (C) 2000  Jon S. Berndt (jsb@hal-pc.org) -------------
   9
  10  This program is free software; you can redistribute it and/or modify it under
  11  the terms of the GNU General Public License as published by the Free Software
  12  Foundation; either version 2 of the License, or (at your option) any later
  13  version.
  14
  15  This program is distributed in the hope that it will be useful, but WITHOUT
  16  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  18  details.
  19
  20  You should have received a copy of the GNU General Public License along with
  21  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  22  Place - Suite 330, Boston, MA  02111-1307, USA.
  23
  24  Further information about the GNU General Public License can also be found on
  25  the world wide web at http://www.gnu.org.
  26
  27 FUNCTIONAL DESCRIPTION
  28 --------------------------------------------------------------------------------
  29
  30 HISTORY
  31 --------------------------------------------------------------------------------
  32 09/13/00   JSB   Created
  33 04/22/01   JSB   Moved code into here from FGAircraft
  34
  35 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  36 INCLUDES
  37 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  38
  39 #include "FGAerodynamics.h"
  40 #include "FGFactorGroup.h"
  41 #include "FGCoefficient.h"
  42 #include "FGPropertyManager.h"
  43
  44 namespace JSBSim {
  45
  46 static const char *IdSrc = "$Id$";
  47 static const char *IdHdr = ID_AERODYNAMICS;
  48
  49 const unsigned NAxes=6;
  50 const char* AxisNames[] = { "drag", "side-force", "lift", "rolling-moment",
  51                             "pitching-moment","yawing-moment" };
  52
  53 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  54 CLASS IMPLEMENTATION
  55 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  56
  57
  58 FGAerodynamics::FGAerodynamics(FGFDMExec* FDMExec) : FGModel(FDMExec)
  59 {
  60   Name = "FGAerodynamics";
  61
  62   AxisIdx["DRAG"]  = 0;
  63   AxisIdx["SIDE"]  = 1;
  64   AxisIdx["LIFT"]  = 2;
  65   AxisIdx["ROLL"]  = 3;
  66   AxisIdx["PITCH"] = 4;
  67   AxisIdx["YAW"]   = 5;
  68
  69   Coeff = new CoeffArray[6];
  70
  71   impending_stall = stall_hyst = 0.0;
  72   alphaclmin = alphaclmax = 0.0;
  73   alphahystmin = alphahystmax = 0.0;
  74   clsq = lod = 0.0;
  75   alphaw = 0.0;
  76   bi2vel = ci2vel = 0.0;
  77   bind();
  78
  79   Debug(0);
  80 }
  81
  82 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  83
  84 FGAerodynamics::~FGAerodynamics()
  85 {
  86   unsigned int i,j;
  87
  88   unbind();
  89
  90   for (i=0; i<6; i++) {
  91     for (j=0; j<Coeff[i].size(); j++) {
  92       delete Coeff[i][j];
  93     }
  94   }
  95   delete[] Coeff;
  96
  97   Debug(1);
  98 }
  99
 100 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 101
 102 bool FGAerodynamics::Run(void)
 103 {
 104   unsigned int axis_ctr,ctr;
 105   double alpha, twovel;
 106
 107   if (!FGModel::Run()) {
 108
 109     twovel = 2*Translation->GetVt();
 110     if (twovel > 0) {
 111       bi2vel = Aircraft->GetWingSpan() / twovel;
 112       ci2vel = Aircraft->Getcbar() / twovel;
 113     }
 114
 115     alphaw = Translation->Getalpha() + Aircraft->GetWingIncidence();
 116
 117     alpha = Translation->Getalpha();
 118
 119     if (alphaclmax != 0) {
 120       if (alpha > 0.85*alphaclmax) {
 121         impending_stall = 10*(alpha/alphaclmax - 0.85);
 122       } else {
 123         impending_stall = 0;
 124       }
 125     }
 126
 127     if (alphahystmax != 0.0 && alphahystmin != 0.0) {
 128       if (alpha > alphahystmax) {
 129          stall_hyst = 1;
 130       } else if (alpha < alphahystmin) {
 131          stall_hyst = 0;
 132       }
 133     }
 134
 135     vLastFs = vFs;
 136     vFs.InitMatrix();
 137
 138     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 139       for (ctr=0; ctr < Coeff[axis_ctr].size(); ctr++) {
 140         vFs(axis_ctr+1) += Coeff[axis_ctr][ctr]->TotalValue();
 141       }
 142     }
 143
 144     //correct signs of drag and lift to wind axes convention
 145     //positive forward, right, down
 146     if ( Translation->Getqbar() > 0) {
 147       clsq = vFs(eLift) / (Aircraft->GetWingArea()*Translation->Getqbar());
 148       clsq *= clsq;
 149     }
 150     if ( vFs(eDrag)  > 0) {
 151       lod = vFs(eLift) / vFs(eDrag);
 152     }
 153
 154     //correct signs of drag and lift to wind axes convention
 155     //positive forward, right, down
 156     vFs(eDrag)*=-1; vFs(eLift)*=-1;
 157
 158     vForces = State->GetTs2b()*vFs;
 159
 160     vDXYZcg(eX) = -(Aircraft->GetXYZrp(eX)
 161                       - MassBalance->GetXYZcg(eX))*inchtoft;
 162     vDXYZcg(eY) =  (Aircraft->GetXYZrp(eY)
 163                       - MassBalance->GetXYZcg(eY))*inchtoft;
 164     vDXYZcg(eZ) = -(Aircraft->GetXYZrp(eZ)
 165                       - MassBalance->GetXYZcg(eZ))*inchtoft;
 166
 167     vMoments = vDXYZcg*vForces; // M = r X F
 168
 169     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 170       for (ctr = 0; ctr < Coeff[axis_ctr+3].size(); ctr++) {
 171         vMoments(axis_ctr+1) += Coeff[axis_ctr+3][ctr]->TotalValue();
 172       }
 173     }
 174
 175     return false;
 176   } else {
 177     return true;
 178   }
 179 }
 180
 181 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 182
 183 bool FGAerodynamics::Load(FGConfigFile* AC_cfg)
 184 {
 185   string parameter, axis, scratch;
 186
 187   AC_cfg->GetNextConfigLine();
 188
 189   while ((parameter = AC_cfg->GetValue()) != string("/AERODYNAMICS")) {
 190     if (parameter == "AXIS") {
 191       CoeffArray ca;
 192       axis = AC_cfg->GetValue("NAME");
 193       AC_cfg->GetNextConfigLine();
 194       while ((parameter = AC_cfg->GetValue()) != string("/AXIS")) {
 195         if ( parameter == "COEFFICIENT" ) {
 196           ca.push_back( new FGCoefficient(FDMExec) );
 197           ca.back()->Load(AC_cfg);
 198         } else if ( parameter == "GROUP" ) {
 199           ca.push_back( new FGFactorGroup(FDMExec) );
 200           ca.back()->Load(AC_cfg);
 201         }
 202       }
 203       Coeff[AxisIdx[axis]] = ca;
 204       AC_cfg->GetNextConfigLine();
 205     } else if (parameter == "AC_ALPHALIMITS") {
 206       *AC_cfg >> scratch >> alphaclmin >> alphaclmax;
 207       if (debug_lvl > 0) cout << "    Maximum Alpha: " << alphaclmax
 208                               << "    Minimum Alpha: " << alphaclmin
 209                               << endl;
 210     } else if (parameter == "AC_HYSTLIMITS") {
 211       *AC_cfg >> scratch >> alphahystmin >> alphahystmax;
 212       if (debug_lvl > 0) cout << "    Hysteresis Start: " << alphahystmax
 213                               << "    Hysteresis End: " << alphahystmin
 214                               << endl;
 215     }
 216   }
 217
 218   bindModel();
 219
 220   return true;
 221 }
 222
 223 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 224
 225 string FGAerodynamics::GetCoefficientStrings(void)
 226 {
 227   string CoeffStrings = "";
 228   bool firstime = true;
 229   unsigned int axis, sd;
 230
 231   for (axis = 0; axis < 6; axis++) {
 232     for (sd = 0; sd < Coeff[axis].size(); sd++) {
 233       if (firstime) {
 234         firstime = false;
 235       } else {
 236         CoeffStrings += ", ";
 237       }
 238       CoeffStrings += Coeff[axis][sd]->GetCoefficientName();
 239     }
 240   }
 241   return CoeffStrings;
 242 }
 243
 244 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 245
 246 string FGAerodynamics::GetCoefficientValues(void)
 247 {
 248   string SDValues = "";
 249   bool firstime = true;
 250
 251   for (unsigned int axis = 0; axis < 6; axis++) {
 252     for (unsigned int sd = 0; sd < Coeff[axis].size(); sd++) {
 253       if (firstime) {
 254         firstime = false;
 255       } else {
 256         SDValues += ", ";
 257       }
 258       SDValues += Coeff[axis][sd]->GetSDstring();
 259     }
 260   }
 261
 262   return SDValues;
 263 }
 264
 265 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 266
 267 void FGAerodynamics::bind(void)
 268 {
 269   typedef double (FGAerodynamics::*PMF)(int) const;
 270
 271   PropertyManager->Tie("forces/fbx-aero-lbs", this,1,
 272                        (PMF)&FGAerodynamics::GetForces);
 273   PropertyManager->Tie("forces/fby-aero-lbs", this,2,
 274                        (PMF)&FGAerodynamics::GetForces);
 275   PropertyManager->Tie("forces/fbz-aero-lbs", this,3,
 276                        (PMF)&FGAerodynamics::GetForces);
 277   PropertyManager->Tie("moments/l-aero-lbsft", this,1,
 278                        (PMF)&FGAerodynamics::GetMoments);
 279   PropertyManager->Tie("moments/m-aero-lbsft", this,2,
 280                        (PMF)&FGAerodynamics::GetMoments);
 281   PropertyManager->Tie("moments/n-aero-lbsft", this,3,
 282                        (PMF)&FGAerodynamics::GetMoments);
 283   PropertyManager->Tie("forces/fwx-aero-lbs", this,1,
 284                        (PMF)&FGAerodynamics::GetvFs);
 285   PropertyManager->Tie("forces/fwy-aero-lbs", this,2,
 286                        (PMF)&FGAerodynamics::GetvFs);
 287   PropertyManager->Tie("forces/fwz-aero-lbs", this,3,
 288                        (PMF)&FGAerodynamics::GetvFs);
 289   PropertyManager->Tie("forces/lod-norm", this,
 290                        &FGAerodynamics::GetLoD);
 291   PropertyManager->Tie("aero/cl-squared-norm", this,
 292                        &FGAerodynamics::GetClSquared);
 293   PropertyManager->Tie("aero/alpha-max-deg", this,
 294                        &FGAerodynamics::GetAlphaCLMax,
 295                        &FGAerodynamics::SetAlphaCLMax,
 296                        true);
 297   PropertyManager->Tie("aero/alpha-min-deg", this,
 298                        &FGAerodynamics::GetAlphaCLMin,
 299                        &FGAerodynamics::SetAlphaCLMin,
 300                        true);
 301   PropertyManager->Tie("aero/bi2vel", this,
 302                        &FGAerodynamics::GetBI2Vel);
 303   PropertyManager->Tie("aero/ci2vel", this,
 304                        &FGAerodynamics::GetCI2Vel);
 305   PropertyManager->Tie("aero/alpha-wing-rad", this,
 306                        &FGAerodynamics::GetAlphaW);
 307   PropertyManager->Tie("systems/stall-warn-norm", this,
 308                         &FGAerodynamics::GetStallWarn);
 309   PropertyManager->Tie("aero/stall-hyst-norm", this,
 310                         &FGAerodynamics::GetHysteresisParm);
 311 }
 312
 313 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 314
 315 void FGAerodynamics::bindModel(void)
 316 {
 317   unsigned i,j;
 318   FGPropertyManager* node;
 319   string axis_node_name;
 320   node = PropertyManager->GetNode("aero/buildup",true);
 321   for (i=0;i<NAxes;i++) {
 322      node = node->GetNode( string(AxisNames[i]),true );
 323      for (j=0; j < Coeff[i].size(); j++) {
 324        Coeff[i][j]->bind(node);
 325      }
 326      node = (FGPropertyManager*)node->getParent();
 327   }
 328 }
 329
 330 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 331
 332 void FGAerodynamics::unbind(void)
 333 {
 334   unsigned i,j;
 335
 336   PropertyManager->Untie("forces/fbx-aero-lbs");
 337   PropertyManager->Untie("forces/fby-aero-lbs");
 338   PropertyManager->Untie("forces/fbz-aero-lbs");
 339   PropertyManager->Untie("moments/l-aero-lbsft");
 340   PropertyManager->Untie("moments/m-aero-lbsft");
 341   PropertyManager->Untie("moments/n-aero-lbsft");
 342   PropertyManager->Untie("forces/fwx-aero-lbs");
 343   PropertyManager->Untie("forces/fwy-aero-lbs");
 344   PropertyManager->Untie("forces/fwz-aero-lbs");
 345   PropertyManager->Untie("forces/lod-norm");
 346   PropertyManager->Untie("aero/cl-squared-norm");
 347   PropertyManager->Untie("aero/alpha-max-deg");
 348   PropertyManager->Untie("aero/alpha-min-deg");
 349   PropertyManager->Untie("aero/bi2vel");
 350   PropertyManager->Untie("aero/ci2vel");
 351   PropertyManager->Untie("aero/alpha-wing-rad");
 352   PropertyManager->Untie("aero/stall-hyst-norm");
 353   PropertyManager->Untie("systems/stall-warn-norm");
 354
 355   for ( i=0; i<NAxes; i++ ) {
 356      for ( j=0; j < Coeff[i].size(); j++ ) {
 357        Coeff[i][j]->unbind();
 358
 359      }
 360   }
 361 }
 362
 363 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 364 //    The bitmasked value choices are as follows:
 365 //    unset: In this case (the default) JSBSim would only print
 366 //       out the normally expected messages, essentially echoing
 367 //       the config files as they are read. If the environment
 368 //       variable is not set, debug_lvl is set to 1 internally
 369 //    0: This requests JSBSim not to output any messages
 370 //       whatsoever.
 371 //    1: This value explicity requests the normal JSBSim
 372 //       startup messages
 373 //    2: This value asks for a message to be printed out when
 374 //       a class is instantiated
 375 //    4: When this value is set, a message is displayed when a
 376 //       FGModel object executes its Run() method
 377 //    8: When this value is set, various runtime state variables
 378 //       are printed out periodically
 379 //    16: When set various parameters are sanity checked and
 380 //       a message is printed out when they go out of bounds
 381
 382 void FGAerodynamics::Debug(int from)
 383 {
 384   if (debug_lvl <= 0) return;
 385
 386   if (debug_lvl & 1) { // Standard console startup message output
 387     if (from == 0) { // Constructor
 388
 389     }
 390   }
 391   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 392     if (from == 0) cout << "Instantiated: FGAerodynamics" << endl;
 393     if (from == 1) cout << "Destroyed:    FGAerodynamics" << endl;
 394   }
 395   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 396   }
 397   if (debug_lvl & 8 ) { // Runtime state variables
 398   }
 399   if (debug_lvl & 16) { // Sanity checking
 400   }
 401   if (debug_lvl & 64) {
 402     if (from == 0) { // Constructor
 403       cout << IdSrc << endl;
 404       cout << IdHdr << endl;
 405     }
 406   }
 407 }
 408
 409 } // namespace JSBSim