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