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 #ifdef HAVE_CONFIG_H
  40 #  include <config.h>
  41 #endif
  42
  43 #include "FGAerodynamics.h"
  44 #include "FGPropagate.h"
  45 #include "FGAircraft.h"
  46 #include "FGState.h"
  47 #include "FGMassBalance.h"
  48 #include "FGFactorGroup.h"
  49 #include "FGPropertyManager.h"
  50
  51 namespace JSBSim {
  52
  53 static const char *IdSrc = "$Id$";
  54 static const char *IdHdr = ID_AERODYNAMICS;
  55
  56 const unsigned NAxes=6;
  57 const char* AxisNames[] = { "drag", "side", "lift", "roll",
  58                             "pitch","yaw" };
  59 const char* AxisNamesUpper[] = { "DRAG", "SIDE", "LIFT", "ROLL",
  60                                  "PITCH","YAW" };
  61
  62 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  63 CLASS IMPLEMENTATION
  64 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  65
  66
  67 FGAerodynamics::FGAerodynamics(FGFDMExec* FDMExec) : FGModel(FDMExec)
  68 {
  69   Name = "FGAerodynamics";
  70
  71   AxisIdx["DRAG"]  = 0;
  72   AxisIdx["SIDE"]  = 1;
  73   AxisIdx["LIFT"]  = 2;
  74   AxisIdx["ROLL"]  = 3;
  75   AxisIdx["PITCH"] = 4;
  76   AxisIdx["YAW"]   = 5;
  77
  78   Coeff = new CoeffArray[6];
  79
  80   impending_stall = stall_hyst = 0.0;
  81   alphaclmin = alphaclmax = 0.0;
  82   alphahystmin = alphahystmax = 0.0;
  83   clsq = lod = 0.0;
  84   alphaw = 0.0;
  85   bi2vel = ci2vel = 0.0;
  86   bind();
  87
  88   Debug(0);
  89 }
  90
  91 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  92
  93 FGAerodynamics::~FGAerodynamics()
  94 {
  95   unsigned int i,j;
  96
  97   unbind();
  98
  99   for (i=0; i<6; i++) {
 100     for (j=0; j<Coeff[i].size(); j++) {
 101       delete Coeff[i][j];
 102     }
 103   }
 104   delete[] Coeff;
 105
 106   Debug(1);
 107 }
 108
 109 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 110
 111 bool FGAerodynamics::Run(void)
 112 {
 113   unsigned int axis_ctr,ctr;
 114   double alpha, twovel;
 115
 116   if (!FGModel::Run()) {
 117
 118     twovel = 2*Auxiliary->GetVt();
 119     if (twovel != 0) {
 120       bi2vel = Aircraft->GetWingSpan() / twovel;
 121       ci2vel = Aircraft->Getcbar() / twovel;
 122     }
 123
 124     alphaw = Auxiliary->Getalpha() + Aircraft->GetWingIncidence();
 125
 126     alpha = Auxiliary->Getalpha();
 127
 128     if (alphaclmax != 0) {
 129       if (alpha > 0.85*alphaclmax) {
 130         impending_stall = 10*(alpha/alphaclmax - 0.85);
 131       } else {
 132         impending_stall = 0;
 133       }
 134     }
 135
 136     if (alphahystmax != 0.0 && alphahystmin != 0.0) {
 137       if (alpha > alphahystmax) {
 138          stall_hyst = 1;
 139       } else if (alpha < alphahystmin) {
 140          stall_hyst = 0;
 141       }
 142     }
 143
 144     vLastFs = vFs;
 145     vFs.InitMatrix();
 146
 147     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 148       for (ctr=0; ctr < Coeff[axis_ctr].size(); ctr++) {
 149         vFs(axis_ctr+1) += Coeff[axis_ctr][ctr]->TotalValue();
 150       }
 151     }
 152
 153     //correct signs of drag and lift to wind axes convention
 154     //positive forward, right, down
 155     if ( Auxiliary->Getqbar() > 0) {
 156       clsq = vFs(eLift) / (Aircraft->GetWingArea()*Auxiliary->Getqbar());
 157       clsq *= clsq;
 158     }
 159     if ( vFs(eDrag)  > 0) {
 160       lod = vFs(eLift) / vFs(eDrag);
 161     }
 162
 163     //correct signs of drag and lift to wind axes convention
 164     //positive forward, right, down
 165     vFs(eDrag)*=-1; vFs(eLift)*=-1;
 166
 167     vForces = State->GetTs2b()*vFs;
 168
 169     vDXYZcg = MassBalance->StructuralToBody(Aircraft->GetXYZrp());
 170
 171     vMoments = vDXYZcg*vForces; // M = r X F
 172
 173     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 174       for (ctr = 0; ctr < Coeff[axis_ctr+3].size(); ctr++) {
 175         vMoments(axis_ctr+1) += Coeff[axis_ctr+3][ctr]->TotalValue();
 176       }
 177     }
 178
 179     return false;
 180   } else {
 181     return true;
 182   }
 183 }
 184
 185 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 186
 187 bool FGAerodynamics::Load(FGConfigFile* AC_cfg)
 188 {
 189   string parameter, axis, scratch;
 190
 191   AC_cfg->GetNextConfigLine();
 192
 193   while ((parameter = AC_cfg->GetValue()) != string("/AERODYNAMICS")) {
 194     if (parameter == "AXIS") {
 195       CoeffArray ca;
 196       axis = AC_cfg->GetValue("NAME");
 197       AC_cfg->GetNextConfigLine();
 198       while ((parameter = AC_cfg->GetValue()) != string("/AXIS")) {
 199         if ( parameter == "COEFFICIENT" ) {
 200           ca.push_back( new FGCoefficient(FDMExec) );
 201           ca.back()->Load(AC_cfg);
 202         } else if ( parameter == "GROUP" ) {
 203           ca.push_back( new FGFactorGroup(FDMExec) );
 204           ca.back()->Load(AC_cfg);
 205         }
 206       }
 207       Coeff[AxisIdx[axis]] = ca;
 208       AC_cfg->GetNextConfigLine();
 209     } else if (parameter == "AC_ALPHALIMITS") {
 210       *AC_cfg >> scratch >> alphaclmin >> alphaclmax;
 211       if (debug_lvl > 0) cout << "    Maximum Alpha: " << alphaclmax
 212                               << "    Minimum Alpha: " << alphaclmin
 213                               << endl;
 214     } else if (parameter == "AC_HYSTLIMITS") {
 215       *AC_cfg >> scratch >> alphahystmin >> alphahystmax;
 216       if (debug_lvl > 0) cout << "    Hysteresis Start: " << alphahystmax
 217                               << "    Hysteresis End: " << alphahystmin
 218                               << endl;
 219     }
 220   }
 221
 222   bindModel();
 223
 224   return true;
 225 }
 226
 227 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 228
 229 string FGAerodynamics::GetCoefficientStrings(string delimeter)
 230 {
 231   string CoeffStrings = "";
 232   bool firstime = true;
 233   unsigned int axis, sd;
 234
 235   for (axis = 0; axis < 6; axis++) {
 236     for (sd = 0; sd < Coeff[axis].size(); sd++) {
 237       if (firstime) {
 238         firstime = false;
 239       } else {
 240         CoeffStrings += delimeter;
 241       }
 242       CoeffStrings += Coeff[axis][sd]->GetCoefficientName();
 243     }
 244   }
 245   return CoeffStrings;
 246 }
 247
 248 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 249
 250 string FGAerodynamics::GetCoefficientValues(string delimeter)
 251 {
 252   string SDValues = "";
 253   bool firstime = true;
 254
 255   for (unsigned int axis = 0; axis < 6; axis++) {
 256     for (unsigned int sd = 0; sd < Coeff[axis].size(); sd++) {
 257       if (firstime) {
 258         firstime = false;
 259       } else {
 260         SDValues += delimeter;
 261       }
 262       SDValues += Coeff[axis][sd]->GetSDstring();
 263     }
 264   }
 265
 266   return SDValues;
 267 }
 268
 269 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 270
 271 void FGAerodynamics::bind(void)
 272 {
 273   typedef double (FGAerodynamics::*PMF)(int) const;
 274
 275   PropertyManager->Tie("forces/fbx-aero-lbs", this,1,
 276                        (PMF)&FGAerodynamics::GetForces);
 277   PropertyManager->Tie("forces/fby-aero-lbs", this,2,
 278                        (PMF)&FGAerodynamics::GetForces);
 279   PropertyManager->Tie("forces/fbz-aero-lbs", this,3,
 280                        (PMF)&FGAerodynamics::GetForces);
 281   PropertyManager->Tie("moments/l-aero-lbsft", this,1,
 282                        (PMF)&FGAerodynamics::GetMoments);
 283   PropertyManager->Tie("moments/m-aero-lbsft", this,2,
 284                        (PMF)&FGAerodynamics::GetMoments);
 285   PropertyManager->Tie("moments/n-aero-lbsft", this,3,
 286                        (PMF)&FGAerodynamics::GetMoments);
 287   PropertyManager->Tie("forces/fwx-aero-lbs", this,1,
 288                        (PMF)&FGAerodynamics::GetvFs);
 289   PropertyManager->Tie("forces/fwy-aero-lbs", this,2,
 290                        (PMF)&FGAerodynamics::GetvFs);
 291   PropertyManager->Tie("forces/fwz-aero-lbs", this,3,
 292                        (PMF)&FGAerodynamics::GetvFs);
 293   PropertyManager->Tie("forces/lod-norm", this,
 294                        &FGAerodynamics::GetLoD);
 295   PropertyManager->Tie("aero/cl-squared-norm", this,
 296                        &FGAerodynamics::GetClSquared);
 297   PropertyManager->Tie("aero/alpha-max-deg", this,
 298                        &FGAerodynamics::GetAlphaCLMax,
 299                        &FGAerodynamics::SetAlphaCLMax,
 300                        true);
 301   PropertyManager->Tie("aero/alpha-min-deg", this,
 302                        &FGAerodynamics::GetAlphaCLMin,
 303                        &FGAerodynamics::SetAlphaCLMin,
 304                        true);
 305   PropertyManager->Tie("aero/bi2vel", this,
 306                        &FGAerodynamics::GetBI2Vel);
 307   PropertyManager->Tie("aero/ci2vel", this,
 308                        &FGAerodynamics::GetCI2Vel);
 309   PropertyManager->Tie("aero/alpha-wing-rad", this,
 310                        &FGAerodynamics::GetAlphaW);
 311   PropertyManager->Tie("systems/stall-warn-norm", this,
 312                         &FGAerodynamics::GetStallWarn);
 313   PropertyManager->Tie("aero/stall-hyst-norm", this,
 314                         &FGAerodynamics::GetHysteresisParm);
 315 }
 316
 317 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 318
 319 void FGAerodynamics::bindModel(void)
 320 {
 321   unsigned i,j;
 322   FGPropertyManager* node;
 323   string axis_node_name;
 324   node = PropertyManager->GetNode("aero/buildup",true);
 325   for (i=0;i<NAxes;i++) {
 326      node = node->GetNode( string(AxisNames[i]),true );
 327      for (j=0; j < Coeff[i].size(); j++) {
 328        Coeff[i][j]->bind(node);
 329      }
 330      node = (FGPropertyManager*)node->getParent();
 331   }
 332 }
 333
 334 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 335
 336 void FGAerodynamics::unbind(void)
 337 {
 338   unsigned i,j;
 339
 340   PropertyManager->Untie("forces/fbx-aero-lbs");
 341   PropertyManager->Untie("forces/fby-aero-lbs");
 342   PropertyManager->Untie("forces/fbz-aero-lbs");
 343   PropertyManager->Untie("moments/l-aero-lbsft");
 344   PropertyManager->Untie("moments/m-aero-lbsft");
 345   PropertyManager->Untie("moments/n-aero-lbsft");
 346   PropertyManager->Untie("forces/fwx-aero-lbs");
 347   PropertyManager->Untie("forces/fwy-aero-lbs");
 348   PropertyManager->Untie("forces/fwz-aero-lbs");
 349   PropertyManager->Untie("forces/lod-norm");
 350   PropertyManager->Untie("aero/cl-squared-norm");
 351   PropertyManager->Untie("aero/alpha-max-deg");
 352   PropertyManager->Untie("aero/alpha-min-deg");
 353   PropertyManager->Untie("aero/bi2vel");
 354   PropertyManager->Untie("aero/ci2vel");
 355   PropertyManager->Untie("aero/alpha-wing-rad");
 356   PropertyManager->Untie("aero/stall-hyst-norm");
 357   PropertyManager->Untie("systems/stall-warn-norm");
 358
 359   for ( i=0; i<NAxes; i++ ) {
 360      for ( j=0; j < Coeff[i].size(); j++ ) {
 361        Coeff[i][j]->unbind();
 362
 363      }
 364   }
 365 }
 366
 367 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 368
 369 void FGAerodynamics::convert(void)
 370 {
 371
 372   for (int axis=0; axis<6; axis++) {
 373     if (Coeff[axis].size()>0) {
 374       cout << endl << "        <axis name=\"" << AxisNamesUpper[axis] << "\">" << endl;
 375       for (int c=0; c<Coeff[axis].size(); c++) {
 376         Coeff[axis][c]->convert();
 377       }
 378       cout << "        </axis>" << endl;
 379     }
 380   }
 381
 382 }
 383
 384 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 385 //    The bitmasked value choices are as follows:
 386 //    unset: In this case (the default) JSBSim would only print
 387 //       out the normally expected messages, essentially echoing
 388 //       the config files as they are read. If the environment
 389 //       variable is not set, debug_lvl is set to 1 internally
 390 //    0: This requests JSBSim not to output any messages
 391 //       whatsoever.
 392 //    1: This value explicity requests the normal JSBSim
 393 //       startup messages
 394 //    2: This value asks for a message to be printed out when
 395 //       a class is instantiated
 396 //    4: When this value is set, a message is displayed when a
 397 //       FGModel object executes its Run() method
 398 //    8: When this value is set, various runtime state variables
 399 //       are printed out periodically
 400 //    16: When set various parameters are sanity checked and
 401 //       a message is printed out when they go out of bounds
 402
 403 void FGAerodynamics::Debug(int from)
 404 {
 405   if (debug_lvl <= 0) return;
 406
 407   if (debug_lvl & 1) { // Standard console startup message output
 408     if (from == 0) { // Constructor
 409
 410     }
 411   }
 412   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 413     if (from == 0) cout << "Instantiated: FGAerodynamics" << endl;
 414     if (from == 1) cout << "Destroyed:    FGAerodynamics" << endl;
 415   }
 416   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 417   }
 418   if (debug_lvl & 8 ) { // Runtime state variables
 419   }
 420   if (debug_lvl & 16) { // Sanity checking
 421   }
 422   if (debug_lvl & 64) {
 423     if (from == 0) { // Constructor
 424       cout << IdSrc << endl;
 425       cout << IdHdr << endl;
 426     }
 427   }
 428 }
 429
 430 } // namespace JSBSim