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