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
  41 static const char *IdSrc = "$Id$";
  42 static const char *IdHdr = ID_AERODYNAMICS;
  43
  44 extern short debug_lvl;
  45
  46 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  47 CLASS IMPLEMENTATION
  48 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  49
  50
  51 FGAerodynamics::FGAerodynamics(FGFDMExec* FDMExec) : FGModel(FDMExec),
  52     vMoments(3),
  53     vForces(3),
  54     vFs(3),
  55     vLastFs(3),
  56     vDXYZcg(3)
  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   if (debug_lvl & 2) cout << "Instantiated: FGAerodynamics" << endl;
  70 }
  71
  72 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  73
  74 FGAerodynamics::~FGAerodynamics()
  75 {
  76   unsigned int i,j;
  77   for (i=0; i<6; i++) {
  78     for (j=0; j<Coeff[i].size(); j++) {
  79       delete Coeff[i][j];
  80     }
  81   }
  82   delete[] Coeff;
  83
  84   if (debug_lvl & 2) cout << "Destroyed:    FGAerodynamics" << endl;
  85 }
  86
  87 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  88
  89 bool FGAerodynamics::Run(void)
  90 {
  91   float alpha, beta;
  92   unsigned int axis_ctr,ctr;
  93
  94   if (!FGModel::Run()) {
  95
  96     alpha = Translation->Getalpha();
  97     beta = Translation->Getbeta();
  98
  99     vLastFs = vFs;
 100     vFs.InitMatrix();
 101
 102     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 103       for (ctr=0; ctr < Coeff[axis_ctr].size(); ctr++) {
 104         vFs(axis_ctr+1) += Coeff[axis_ctr][ctr]->TotalValue();
 105       }
 106     }
 107
 108     vForces = State->GetTs2b(alpha, beta)*vFs;
 109
 110     // see http://home.earthlink.net/~apeden/jsbsim_moments_due_to_forces.txt
 111     // for details on this
 112
 113     vDXYZcg(eX) = -(Aircraft->GetXYZrp(eX) - MassBalance->GetXYZcg(eX))/12.0;
 114     vDXYZcg(eY) =  (Aircraft->GetXYZrp(eY) - MassBalance->GetXYZcg(eY))/12.0;
 115     vDXYZcg(eZ) = -(Aircraft->GetXYZrp(eZ) - MassBalance->GetXYZcg(eZ))/12.0;
 116
 117     vMoments(eL) = vForces(eZ)*vDXYZcg(eY) - vForces(eY)*vDXYZcg(eZ);
 118     vMoments(eM) = vForces(eX)*vDXYZcg(eZ) - vForces(eZ)*vDXYZcg(eX);
 119     vMoments(eN) = vForces(eY)*vDXYZcg(eX) - vForces(eX)*vDXYZcg(eY);
 120
 121     for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
 122       for (ctr = 0; ctr < Coeff[axis_ctr+3].size(); ctr++) {
 123         vMoments(axis_ctr+1) += Coeff[axis_ctr+3][ctr]->TotalValue();
 124       }
 125     }
 126     return false;
 127   } else {
 128     return true;
 129   }
 130 }
 131
 132 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 133
 134 bool FGAerodynamics::Load(FGConfigFile* AC_cfg)
 135 {
 136   string token, axis;
 137
 138   AC_cfg->GetNextConfigLine();
 139
 140   while ((token = AC_cfg->GetValue()) != "/AERODYNAMICS") {
 141     if (token == "AXIS") {
 142       CoeffArray ca;
 143       axis = AC_cfg->GetValue("NAME");
 144       AC_cfg->GetNextConfigLine();
 145       while ((token = AC_cfg->GetValue()) != "/AXIS") {
 146         ca.push_back(new FGCoefficient(FDMExec, AC_cfg));
 147         if (debug_lvl > 0) DisplayCoeffFactors(ca.back()->Getmultipliers());
 148       }
 149       Coeff[AxisIdx[axis]] = ca;
 150       AC_cfg->GetNextConfigLine();
 151     }
 152   }
 153
 154   return true;
 155 }
 156
 157 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 158
 159 void FGAerodynamics::DisplayCoeffFactors(vector <eParam> multipliers)
 160 {
 161   unsigned int i;
 162
 163   cout << "   Non-Dimensionalized by: ";
 164
 165   for (i=0; i<multipliers.size();i++) cout << State->paramdef[multipliers[i]];
 166
 167   cout << endl;
 168 }
 169
 170 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 171
 172 string FGAerodynamics::GetCoefficientStrings(void)
 173 {
 174   string CoeffStrings = "";
 175   bool firstime = true;
 176   unsigned int axis, sd;
 177
 178   for (axis = 0; axis < 6; axis++) {
 179     for (sd = 0; sd < Coeff[axis].size(); sd++) {
 180       if (firstime) {
 181         firstime = false;
 182       } else {
 183         CoeffStrings += ", ";
 184       }
 185       CoeffStrings += Coeff[axis][sd]->Getname();
 186     }
 187   }
 188   return CoeffStrings;
 189 }
 190
 191 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 192
 193 string FGAerodynamics::GetCoefficientValues(void)
 194 {
 195   string SDValues = "";
 196   char buffer[10];
 197   bool firstime = true;
 198
 199   for (unsigned int axis = 0; axis < 6; axis++) {
 200     for (unsigned int sd = 0; sd < Coeff[axis].size(); sd++) {
 201       if (firstime) {
 202         firstime = false;
 203       } else {
 204         SDValues += ", ";
 205       }
 206       sprintf(buffer, "%9.6f", Coeff[axis][sd]->GetSD());
 207       SDValues += string(buffer);
 208     }
 209   }
 210
 211   return SDValues;
 212 }
 213
 214 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 215
 216 float FGAerodynamics::GetNlf(void)
 217 {
 218   if (fabs(Position->GetGamma()) < 1.57) {
 219     return (vFs(eZ)/(MassBalance->GetWeight()*cos(Position->GetGamma())));
 220   } else {
 221     return 0.0;
 222   }
 223 }
 224
 225 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 226
 227 float FGAerodynamics::GetLoD(void)
 228 {
 229   float LoD;
 230
 231   if (vFs(1) != 0.00) return vFs(3)/vFs(1);
 232   else                return 0.00;
 233 }
 234
 235 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 236
 237 void FGAerodynamics::Debug(void)
 238 {
 239     //TODO: Add your source code here
 240 }
 241