src/FDM/JSBSim/models/propulsion/FGEngine.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGEngine.cpp
   4  Author:       Jon Berndt
   5  Date started: 01/21/99
   6  Called by:    FGAircraft
   7
   8  ------------- Copyright (C) 1999  Jon S. Berndt (jon@jsbsim.org) -------------
   9
  10  This program is free software; you can redistribute it and/or modify it under
  11  the terms of the GNU Lesser 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 Lesser General Public License for more details.
  18
  19  You should have received a copy of the GNU Lesser General Public License along with
  20  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  21  Place - Suite 330, Boston, MA  02111-1307, USA.
  22
  23  Further information about the GNU Lesser General Public License can also be found on
  24  the world wide web at http://www.gnu.org.
  25
  26 FUNCTIONAL DESCRIPTION
  27 --------------------------------------------------------------------------------
  28 See header file.
  29
  30 HISTORY
  31 --------------------------------------------------------------------------------
  32 01/21/99   JSB   Created
  33 09/03/99   JSB   Changed Rocket thrust equation to correct -= Thrust instead of
  34                  += Thrust (thanks to Tony Peden)
  35
  36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  37 INCLUDES
  38 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  39
  40 #include "FGEngine.h"
  41 #include "FGTank.h"
  42 #include "FGPropeller.h"
  43 #include "FGNozzle.h"
  44 #include "input_output/FGXMLParse.h"
  45 #include "math/FGColumnVector3.h"
  46 #include <fstream>
  47
  48 namespace JSBSim {
  49
  50 static const char *IdSrc = "$Id$";
  51 static const char *IdHdr = ID_ENGINE;
  52
  53 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  54 CLASS IMPLEMENTATION
  55 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  56
  57 FGEngine::FGEngine(FGFDMExec* exec, Element* engine_element, int engine_number)
  58                       : EngineNumber(engine_number)
  59 {
  60   Element* local_element;
  61   FGColumnVector3 location, orientation;
  62
  63   Name = "";
  64   Type = etUnknown;
  65   X = Y = Z = 0.0;
  66   EnginePitch = EngineYaw = 0.0;
  67   SLFuelFlowMax = 0.0;
  68   MaxThrottle = 1.0;
  69   MinThrottle = 0.0;
  70   unsigned int i;
  71
  72   ResetToIC(); // initialize dynamic terms
  73
  74   FDMExec = exec;
  75   State = FDMExec->GetState();
  76   Atmosphere = FDMExec->GetAtmosphere();
  77   FCS = FDMExec->GetFCS();
  78   Propulsion = FDMExec->GetPropulsion();
  79   Aircraft = FDMExec->GetAircraft();
  80   Propagate = FDMExec->GetPropagate();
  81   Auxiliary = FDMExec->GetAuxiliary();
  82
  83   PropertyManager = FDMExec->GetPropertyManager();
  84
  85   Name = engine_element->GetAttributeValue("name");
  86
  87 // Find and set engine location
  88
  89   local_element = engine_element->GetParent()->FindElement("location");
  90   if (local_element)  location = local_element->FindElementTripletConvertTo("IN");
  91   else      cerr << "No engine location found for this engine." << endl;
  92
  93   local_element = engine_element->GetParent()->FindElement("orient");
  94   if (local_element)  orientation = local_element->FindElementTripletConvertTo("RAD");
  95 //  else          cerr << "No engine orientation found for this engine." << endl;
  96 // Jon: The engine orientation has a default and is not normally used.
  97
  98   SetPlacement(location, orientation);
  99
 100   // Load thruster
 101   local_element = engine_element->GetParent()->FindElement("thruster");
 102   if (local_element) {
 103     if (!LoadThruster(local_element)) exit(-1);
 104   } else {
 105     cerr << "No thruster definition supplied with engine definition." << endl;
 106   }
 107
 108   // Build and initialize the feed tank vector.
 109   for (i=0; i<(Propulsion->GetNumTanks()); i++) {
 110     SourceTanks.push_back(0);
 111   }
 112
 113   // Load feed tank[s] references
 114   local_element = engine_element->GetParent()->FindElement("feed");
 115   if (local_element) {
 116     while (local_element) {
 117       int tankID = (int)local_element->GetDataAsNumber();
 118       AddFeedTank( tankID , Propulsion->GetTank(tankID)->GetPriority());
 119       local_element = engine_element->GetParent()->FindNextElement("feed");
 120     }
 121   } else {
 122     cerr << "No feed tank specified in engine definition." << endl;
 123   }
 124
 125   string property_name, base_property_name;
 126   base_property_name = CreateIndexedPropertyName("propulsion/engine", EngineNumber);
 127
 128   property_name = base_property_name + "/set-running";
 129   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetRunning, &FGEngine::SetRunning );
 130   property_name = base_property_name + "/thrust-lbs";
 131   PropertyManager->Tie( property_name.c_str(), Thruster, &FGThruster::GetThrust);
 132   property_name = base_property_name + "/fuel-flow-rate-pps";
 133   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetFuelFlowRate);
 134
 135   Debug(0);
 136 }
 137
 138 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 139
 140 FGEngine::~FGEngine()
 141 {
 142   delete Thruster;
 143   Debug(1);
 144 }
 145
 146 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 147
 148 void FGEngine::ResetToIC(void)
 149 {
 150   Throttle = 0.0;
 151   Mixture = 1.0;
 152   Starter = false;
 153   FuelExpended = 0.0;
 154   Starved = Running = Cranking = false;
 155   PctPower = 0.0;
 156   TrimMode = false;
 157   FuelFlow_gph = 0.0;
 158   FuelFlow_pph = 0.0;
 159   FuelFreeze = false;
 160 }
 161
 162 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 163 // This base class function should be called from within the
 164 // derived class' Calculate() function before any other calculations are done.
 165 // This base class method removes fuel from the fuel tanks as appropriate,
 166 // and sets the starved flag if necessary.
 167 // This version of the fuel consumption code should never see an oxidizer tank.
 168
 169 void FGEngine::ConsumeFuel(void)
 170 {
 171   if (FuelFreeze) return;
 172   if (TrimMode) return;
 173
 174   unsigned int i;
 175   double Fshortage, FuelNeeded;
 176   FGTank* Tank;
 177   unsigned int TanksWithFuel = 0;
 178   Fshortage = FuelNeeded = 0.0;
 179   double FuelToBurn;
 180   unsigned int CurrentPriority = 1;
 181   vector <int> FeedList;
 182   Starved = false;
 183
 184   FuelToBurn = CalcFuelNeed();
 185   if (FuelToBurn == 0.0) return;
 186
 187   while (FuelToBurn > 0.0) {
 188
 189     // Count how many fuel tanks with the current priority level have fuel.
 190     // If none, then try next lower priority.  Build the feed list.
 191     while ((TanksWithFuel == 0) && (CurrentPriority <= Propulsion->GetNumTanks())) {
 192       for (i=0; i<Propulsion->GetNumTanks(); i++) {
 193         if (SourceTanks[i] != 0) {
 194           Tank = Propulsion->GetTank(i);
 195           if (Tank->GetType() == FGTank::ttFUEL) {
 196             if ((Tank->GetContents() > 0.0) && ((unsigned int)Tank->GetPriority() == CurrentPriority)) {
 197                ++TanksWithFuel;
 198                FeedList.push_back(i);
 199              }
 200           } else {
 201              cerr << "No oxidizer tanks should be used for this engine type." << endl;
 202           }
 203         }
 204       }
 205       if (TanksWithFuel == 0) CurrentPriority++;
 206     }
 207
 208     // No fuel found at any priority!
 209     if (TanksWithFuel == 0) {
 210       Starved = true;
 211       return;
 212     }
 213
 214     // Remove equal amount of fuel from each feed tank.
 215     FuelNeeded = FuelToBurn/TanksWithFuel;
 216     for (i=0; i<FeedList.size(); i++) {
 217       Tank = Propulsion->GetTank(FeedList[i]);
 218       Tank->Drain(FuelNeeded);
 219       FuelToBurn -= FuelNeeded;
 220     }
 221
 222   }  // while
 223 }
 224
 225 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 226
 227 double FGEngine::CalcFuelNeed(void)
 228 {
 229   double dT = State->Getdt()*Propulsion->GetRate();
 230   FuelFlowRate = SLFuelFlowMax*PctPower;
 231   FuelExpended = FuelFlowRate*dT;
 232   return FuelExpended;
 233 }
 234
 235 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 236
 237 void FGEngine::SetPlacement(FGColumnVector3& location, FGColumnVector3& orientation)
 238 {
 239   X = location(eX);
 240   Y = location(eY);
 241   Z = location(eZ);
 242   EnginePitch = orientation(ePitch);
 243   EngineYaw = orientation (eYaw);
 244 }
 245
 246 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 247
 248 void FGEngine::AddFeedTank(int tkID, int priority)
 249 {
 250   SourceTanks[tkID] = priority;
 251 }
 252
 253 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 254
 255 FGColumnVector3& FGEngine::GetBodyForces(void)
 256 {
 257   return Thruster->GetBodyForces();
 258 }
 259
 260 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 261
 262 FGColumnVector3& FGEngine::GetMoments(void)
 263 {
 264   return Thruster->GetMoments();
 265 }
 266
 267 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 268
 269 bool FGEngine::LoadThruster(Element *thruster_element)
 270 {
 271   string token, fullpath, localpath;
 272   string thruster_filename, thruster_fullpathname, thrType;
 273   string enginePath = FDMExec->GetEnginePath();
 274   string aircraftPath = FDMExec->GetFullAircraftPath();
 275   ifstream thruster_file;
 276   FGColumnVector3 location, orientation;
 277   string separator = "/";
 278
 279   fullpath = enginePath + separator;
 280   localpath = aircraftPath + separator + "Engines" + separator;
 281
 282   thruster_filename = thruster_element->GetAttributeValue("file");
 283   if ( !thruster_filename.empty()) {
 284     thruster_fullpathname = fullpath + thruster_filename + ".xml";
 285     thruster_file.open(thruster_fullpathname.c_str());
 286     if ( !thruster_file.is_open()) {
 287       thruster_fullpathname = localpath + thruster_filename + ".xml";
 288       thruster_file.open(thruster_fullpathname.c_str());
 289       if ( !thruster_file.is_open()) {
 290         cerr << "Could not open thruster file: " << thruster_filename << ".xml" << endl;
 291         return false;
 292       } else {
 293         thruster_file.close();
 294       }
 295     } else {
 296       thruster_file.close();
 297     }
 298   } else {
 299     cerr << "No thruster filename given." << endl;
 300     return false;
 301   }
 302
 303   document = LoadXMLDocument(thruster_fullpathname);
 304   document->SetParent(thruster_element);
 305
 306   thrType = document->GetName();
 307
 308   if (thrType == "propeller") {
 309     Thruster = new FGPropeller(FDMExec, document, EngineNumber);
 310   } else if (thrType == "nozzle") {
 311     Thruster = new FGNozzle(FDMExec, document, EngineNumber);
 312   } else if (thrType == "direct") {
 313     Thruster = new FGThruster( FDMExec, document, EngineNumber);
 314   }
 315
 316   Thruster->SetdeltaT(State->Getdt() * Propulsion->GetRate());
 317
 318   Debug(2);
 319   return true;
 320 }
 321
 322 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 323 //    The bitmasked value choices are as follows:
 324 //    unset: In this case (the default) JSBSim would only print
 325 //       out the normally expected messages, essentially echoing
 326 //       the config files as they are read. If the environment
 327 //       variable is not set, debug_lvl is set to 1 internally
 328 //    0: This requests JSBSim not to output any messages
 329 //       whatsoever.
 330 //    1: This value explicity requests the normal JSBSim
 331 //       startup messages
 332 //    2: This value asks for a message to be printed out when
 333 //       a class is instantiated
 334 //    4: When this value is set, a message is displayed when a
 335 //       FGModel object executes its Run() method
 336 //    8: When this value is set, various runtime state variables
 337 //       are printed out periodically
 338 //    16: When set various parameters are sanity checked and
 339 //       a message is printed out when they go out of bounds
 340
 341 void FGEngine::Debug(int from)
 342 {
 343   if (debug_lvl <= 0) return;
 344
 345   if (debug_lvl & 1) { // Standard console startup message output
 346     if (from == 0) { // Constructor
 347
 348     }
 349     if (from == 2) { // After thruster loading
 350       cout << "      X = " << Thruster->GetLocationX() << endl;
 351       cout << "      Y = " << Thruster->GetLocationY() << endl;
 352       cout << "      Z = " << Thruster->GetLocationZ() << endl;
 353       cout << "      Pitch = " << radtodeg*Thruster->GetAnglesToBody(ePitch) << " degrees" << endl;
 354       cout << "      Yaw = " << radtodeg*Thruster->GetAnglesToBody(eYaw) << " degrees" << endl;
 355     }
 356   }
 357   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 358     if (from == 0) cout << "Instantiated: FGEngine" << endl;
 359     if (from == 1) cout << "Destroyed:    FGEngine" << endl;
 360   }
 361   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 362   }
 363   if (debug_lvl & 8 ) { // Runtime state variables
 364   }
 365   if (debug_lvl & 16) { // Sanity checking
 366   }
 367   if (debug_lvl & 64) {
 368     if (from == 0) { // Constructor
 369       cout << IdSrc << endl;
 370       cout << IdHdr << endl;
 371     }
 372   }
 373 }
 374 }