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 = MassBalance->StructuralToBody(Aircraft->GetXYZrp());
 161
 162     vMoments = vDXYZcg*vForces; // M = r X F
 163
 164     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 165       for (ctr = 0; ctr < Coeff[axis_ctr+3].size(); ctr++) {
 166         vMoments(axis_ctr+1) += Coeff[axis_ctr+3][ctr]->TotalValue();
 167       }
 168     }
 169
 170     return false;
 171   } else {
 172     return true;
 173   }
 174 }
 175
 176 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 177
 178 bool FGAerodynamics::Load(FGConfigFile* AC_cfg)
 179 {
 180   string parameter, axis, scratch;
 181
 182   AC_cfg->GetNextConfigLine();
 183
 184   while ((parameter = AC_cfg->GetValue()) != string("/AERODYNAMICS")) {
 185     if (parameter == "AXIS") {
 186       CoeffArray ca;
 187       axis = AC_cfg->GetValue("NAME");
 188       AC_cfg->GetNextConfigLine();
 189       while ((parameter = AC_cfg->GetValue()) != string("/AXIS")) {
 190         if ( parameter == "COEFFICIENT" ) {
 191           ca.push_back( new FGCoefficient(FDMExec) );
 192           ca.back()->Load(AC_cfg);
 193         } else if ( parameter == "GROUP" ) {
 194           ca.push_back( new FGFactorGroup(FDMExec) );
 195           ca.back()->Load(AC_cfg);
 196         }
 197       }
 198       Coeff[AxisIdx[axis]] = ca;
 199       AC_cfg->GetNextConfigLine();
 200     } else if (parameter == "AC_ALPHALIMITS") {
 201       *AC_cfg >> scratch >> alphaclmin >> alphaclmax;
 202       if (debug_lvl > 0) cout << "    Maximum Alpha: " << alphaclmax
 203                               << "    Minimum Alpha: " << alphaclmin
 204                               << endl;
 205     } else if (parameter == "AC_HYSTLIMITS") {
 206       *AC_cfg >> scratch >> alphahystmin >> alphahystmax;
 207       if (debug_lvl > 0) cout << "    Hysteresis Start: " << alphahystmax
 208                               << "    Hysteresis End: " << alphahystmin
 209                               << endl;
 210     }
 211   }
 212
 213   bindModel();
 214
 215   return true;
 216 }
 217
 218 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 219
 220 string FGAerodynamics::GetCoefficientStrings(void)
 221 {
 222   string CoeffStrings = "";
 223   bool firstime = true;
 224   unsigned int axis, sd;
 225
 226   for (axis = 0; axis < 6; axis++) {
 227     for (sd = 0; sd < Coeff[axis].size(); sd++) {
 228       if (firstime) {
 229         firstime = false;
 230       } else {
 231         CoeffStrings += ", ";
 232       }
 233       CoeffStrings += Coeff[axis][sd]->GetCoefficientName();
 234     }
 235   }
 236   return CoeffStrings;
 237 }
 238
 239 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 240
 241 string FGAerodynamics::GetCoefficientValues(void)
 242 {
 243   string SDValues = "";
 244   bool firstime = true;
 245
 246   for (unsigned int axis = 0; axis < 6; axis++) {
 247     for (unsigned int sd = 0; sd < Coeff[axis].size(); sd++) {
 248       if (firstime) {
 249         firstime = false;
 250       } else {
 251         SDValues += ", ";
 252       }
 253       SDValues += Coeff[axis][sd]->GetSDstring();
 254     }
 255   }
 256
 257   return SDValues;
 258 }
 259
 260 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 261
 262 void FGAerodynamics::bind(void)
 263 {
 264   typedef double (FGAerodynamics::*PMF)(int) const;
 265
 266   PropertyManager->Tie("forces/fbx-aero-lbs", this,1,
 267                        (PMF)&FGAerodynamics::GetForces);
 268   PropertyManager->Tie("forces/fby-aero-lbs", this,2,
 269                        (PMF)&FGAerodynamics::GetForces);
 270   PropertyManager->Tie("forces/fbz-aero-lbs", this,3,
 271                        (PMF)&FGAerodynamics::GetForces);
 272   PropertyManager->Tie("moments/l-aero-lbsft", this,1,
 273                        (PMF)&FGAerodynamics::GetMoments);
 274   PropertyManager->Tie("moments/m-aero-lbsft", this,2,
 275                        (PMF)&FGAerodynamics::GetMoments);
 276   PropertyManager->Tie("moments/n-aero-lbsft", this,3,
 277                        (PMF)&FGAerodynamics::GetMoments);
 278   PropertyManager->Tie("forces/fwx-aero-lbs", this,1,
 279                        (PMF)&FGAerodynamics::GetvFs);
 280   PropertyManager->Tie("forces/fwy-aero-lbs", this,2,
 281                        (PMF)&FGAerodynamics::GetvFs);
 282   PropertyManager->Tie("forces/fwz-aero-lbs", this,3,
 283                        (PMF)&FGAerodynamics::GetvFs);
 284   PropertyManager->Tie("forces/lod-norm", this,
 285                        &FGAerodynamics::GetLoD);
 286   PropertyManager->Tie("aero/cl-squared-norm", this,
 287                        &FGAerodynamics::GetClSquared);
 288   PropertyManager->Tie("aero/alpha-max-deg", this,
 289                        &FGAerodynamics::GetAlphaCLMax,
 290                        &FGAerodynamics::SetAlphaCLMax,
 291                        true);
 292   PropertyManager->Tie("aero/alpha-min-deg", this,
 293                        &FGAerodynamics::GetAlphaCLMin,
 294                        &FGAerodynamics::SetAlphaCLMin,
 295                        true);
 296   PropertyManager->Tie("aero/bi2vel", this,
 297                        &FGAerodynamics::GetBI2Vel);
 298   PropertyManager->Tie("aero/ci2vel", this,
 299                        &FGAerodynamics::GetCI2Vel);
 300   PropertyManager->Tie("aero/alpha-wing-rad", this,
 301                        &FGAerodynamics::GetAlphaW);
 302   PropertyManager->Tie("systems/stall-warn-norm", this,
 303                         &FGAerodynamics::GetStallWarn);
 304   PropertyManager->Tie("aero/stall-hyst-norm", this,
 305                         &FGAerodynamics::GetHysteresisParm);
 306 }
 307
 308 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 309
 310 void FGAerodynamics::bindModel(void)
 311 {
 312   unsigned i,j;
 313   FGPropertyManager* node;
 314   string axis_node_name;
 315   node = PropertyManager->GetNode("aero/buildup",true);
 316   for (i=0;i<NAxes;i++) {
 317      node = node->GetNode( string(AxisNames[i]),true );
 318      for (j=0; j < Coeff[i].size(); j++) {
 319        Coeff[i][j]->bind(node);
 320      }
 321      node = (FGPropertyManager*)node->getParent();
 322   }
 323 }
 324
 325 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 326
 327 void FGAerodynamics::unbind(void)
 328 {
 329   unsigned i,j;
 330
 331   PropertyManager->Untie("forces/fbx-aero-lbs");
 332   PropertyManager->Untie("forces/fby-aero-lbs");
 333   PropertyManager->Untie("forces/fbz-aero-lbs");
 334   PropertyManager->Untie("moments/l-aero-lbsft");
 335   PropertyManager->Untie("moments/m-aero-lbsft");
 336   PropertyManager->Untie("moments/n-aero-lbsft");
 337   PropertyManager->Untie("forces/fwx-aero-lbs");
 338   PropertyManager->Untie("forces/fwy-aero-lbs");
 339   PropertyManager->Untie("forces/fwz-aero-lbs");
 340   PropertyManager->Untie("forces/lod-norm");
 341   PropertyManager->Untie("aero/cl-squared-norm");
 342   PropertyManager->Untie("aero/alpha-max-deg");
 343   PropertyManager->Untie("aero/alpha-min-deg");
 344   PropertyManager->Untie("aero/bi2vel");
 345   PropertyManager->Untie("aero/ci2vel");
 346   PropertyManager->Untie("aero/alpha-wing-rad");
 347   PropertyManager->Untie("aero/stall-hyst-norm");
 348   PropertyManager->Untie("systems/stall-warn-norm");
 349
 350   for ( i=0; i<NAxes; i++ ) {
 351      for ( j=0; j < Coeff[i].size(); j++ ) {
 352        Coeff[i][j]->unbind();
 353
 354      }
 355   }
 356 }
 357
 358 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 359 //    The bitmasked value choices are as follows:
 360 //    unset: In this case (the default) JSBSim would only print
 361 //       out the normally expected messages, essentially echoing
 362 //       the config files as they are read. If the environment
 363 //       variable is not set, debug_lvl is set to 1 internally
 364 //    0: This requests JSBSim not to output any messages
 365 //       whatsoever.
 366 //    1: This value explicity requests the normal JSBSim
 367 //       startup messages
 368 //    2: This value asks for a message to be printed out when
 369 //       a class is instantiated
 370 //    4: When this value is set, a message is displayed when a
 371 //       FGModel object executes its Run() method
 372 //    8: When this value is set, various runtime state variables
 373 //       are printed out periodically
 374 //    16: When set various parameters are sanity checked and
 375 //       a message is printed out when they go out of bounds
 376
 377 void FGAerodynamics::Debug(int from)
 378 {
 379   if (debug_lvl <= 0) return;
 380
 381   if (debug_lvl & 1) { // Standard console startup message output
 382     if (from == 0) { // Constructor
 383
 384     }
 385   }
 386   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 387     if (from == 0) cout << "Instantiated: FGAerodynamics" << endl;
 388     if (from == 1) cout << "Destroyed:    FGAerodynamics" << endl;
 389   }
 390   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 391   }
 392   if (debug_lvl & 8 ) { // Runtime state variables
 393   }
 394   if (debug_lvl & 16) { // Sanity checking
 395   }
 396   if (debug_lvl & 64) {
 397     if (from == 0) { // Constructor
 398       cout << IdSrc << endl;
 399       cout << IdHdr << endl;
 400     }
 401   }
 402 }
 403
 404 } // namespace JSBSim