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, TanksWithFuel, FuelNeeded;
 176   FGTank* Tank;
 177   Fshortage = TanksWithFuel = FuelNeeded = 0.0;
 178   double FuelToBurn = CalcFuelNeed();
 179   unsigned int CurrentPriority = 1;
 180   vector <int> FeedList;
 181   Starved = false;
 182
 183   while (FuelToBurn > 0.0) {
 184
 185     // Count how many fuel tanks with the current priority level have fuel.
 186     // If none, then try next lower priority.  Build the feed list.
 187     while ((TanksWithFuel == 0.0) && (CurrentPriority <= Propulsion->GetNumTanks())) {
 188       for (i=0; i<Propulsion->GetNumTanks(); i++) {
 189         Tank = Propulsion->GetTank(i);
 190         if (Tank->GetType() == FGTank::ttFUEL) {
 191           if ((Tank->GetContents() > 0.0) && ((unsigned int)Tank->GetPriority() == CurrentPriority)) {
 192              ++TanksWithFuel;
 193              FeedList.push_back(i);
 194            }
 195         } else {
 196            cerr << "No oxidizer tanks should be used for this engine type." << endl;
 197         }
 198       }
 199       if (TanksWithFuel == 0.0) CurrentPriority++;
 200     }
 201
 202     // No fuel found at any priority!
 203     if (TanksWithFuel == 0.0) {
 204       Starved = true;
 205       return;
 206     }
 207
 208     // Remove equal amount of fuel from each feed tank.
 209     FuelNeeded = FuelToBurn/TanksWithFuel;
 210     for (i=0; i<FeedList.size(); i++) {
 211       Tank = Propulsion->GetTank(FeedList[i]);
 212       Tank->Drain(FuelNeeded);
 213       FuelToBurn -= FuelNeeded;
 214     }
 215
 216     // check if we were not able to burn all the fuel we needed to at this priority level
 217     if (FuelToBurn > 0.001) {
 218       CurrentPriority++;
 219       TanksWithFuel = 0.0;
 220       FeedList.clear();
 221     }
 222
 223   }  // while
 224 }
 225
 226 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 227
 228 double FGEngine::CalcFuelNeed(void)
 229 {
 230   double dT = State->Getdt()*Propulsion->GetRate();
 231   FuelFlowRate = SLFuelFlowMax*PctPower;
 232   FuelExpended = FuelFlowRate*dT;
 233   return FuelExpended;
 234 }
 235
 236 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 237
 238 void FGEngine::SetPlacement(FGColumnVector3& location, FGColumnVector3& orientation)
 239 {
 240   X = location(eX);
 241   Y = location(eY);
 242   Z = location(eZ);
 243   EnginePitch = orientation(ePitch);
 244   EngineYaw = orientation (eYaw);
 245 }
 246
 247 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 248
 249 void FGEngine::AddFeedTank(int tkID, int priority)
 250 {
 251   SourceTanks[tkID] = priority;
 252 }
 253
 254 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 255
 256 FGColumnVector3& FGEngine::GetBodyForces(void)
 257 {
 258   return Thruster->GetBodyForces();
 259 }
 260
 261 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 262
 263 FGColumnVector3& FGEngine::GetMoments(void)
 264 {
 265   return Thruster->GetMoments();
 266 }
 267
 268 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 269
 270 bool FGEngine::LoadThruster(Element *thruster_element)
 271 {
 272   string token, fullpath, localpath;
 273   string thruster_filename, thruster_fullpathname, thrType;
 274   string enginePath = FDMExec->GetEnginePath();
 275   string aircraftPath = FDMExec->GetFullAircraftPath();
 276   ifstream thruster_file;
 277   FGColumnVector3 location, orientation;
 278   string separator = "/";
 279
 280   fullpath = enginePath + separator;
 281   localpath = aircraftPath + separator + "Engines" + separator;
 282
 283   thruster_filename = thruster_element->GetAttributeValue("file");
 284   if ( !thruster_filename.empty()) {
 285     thruster_fullpathname = fullpath + thruster_filename + ".xml";
 286     thruster_file.open(thruster_fullpathname.c_str());
 287     if ( !thruster_file.is_open()) {
 288       thruster_fullpathname = localpath + thruster_filename + ".xml";
 289       thruster_file.open(thruster_fullpathname.c_str());
 290       if ( !thruster_file.is_open()) {
 291         cerr << "Could not open thruster file: " << thruster_filename << ".xml" << endl;
 292         return false;
 293       } else {
 294         thruster_file.close();
 295       }
 296     } else {
 297       thruster_file.close();
 298     }
 299   } else {
 300     cerr << "No thruster filename given." << endl;
 301     return false;
 302   }
 303
 304   document = LoadXMLDocument(thruster_fullpathname);
 305   document->SetParent(thruster_element);
 306
 307   thrType = document->GetName();
 308
 309   if (thrType == "propeller") {
 310     Thruster = new FGPropeller(FDMExec, document, EngineNumber);
 311   } else if (thrType == "nozzle") {
 312     Thruster = new FGNozzle(FDMExec, document, EngineNumber);
 313   } else if (thrType == "direct") {
 314     Thruster = new FGThruster( FDMExec, document, EngineNumber);
 315   }
 316
 317   Thruster->SetdeltaT(State->Getdt() * Propulsion->GetRate());
 318
 319   Debug(2);
 320   return true;
 321 }
 322
 323 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 324 //    The bitmasked value choices are as follows:
 325 //    unset: In this case (the default) JSBSim would only print
 326 //       out the normally expected messages, essentially echoing
 327 //       the config files as they are read. If the environment
 328 //       variable is not set, debug_lvl is set to 1 internally
 329 //    0: This requests JSBSim not to output any messages
 330 //       whatsoever.
 331 //    1: This value explicity requests the normal JSBSim
 332 //       startup messages
 333 //    2: This value asks for a message to be printed out when
 334 //       a class is instantiated
 335 //    4: When this value is set, a message is displayed when a
 336 //       FGModel object executes its Run() method
 337 //    8: When this value is set, various runtime state variables
 338 //       are printed out periodically
 339 //    16: When set various parameters are sanity checked and
 340 //       a message is printed out when they go out of bounds
 341
 342 void FGEngine::Debug(int from)
 343 {
 344   if (debug_lvl <= 0) return;
 345
 346   if (debug_lvl & 1) { // Standard console startup message output
 347     if (from == 0) { // Constructor
 348
 349     }
 350     if (from == 2) { // After thruster loading
 351       cout << "      X = " << Thruster->GetLocationX() << endl;
 352       cout << "      Y = " << Thruster->GetLocationY() << endl;
 353       cout << "      Z = " << Thruster->GetLocationZ() << endl;
 354       cout << "      Pitch = " << radtodeg*Thruster->GetAnglesToBody(ePitch) << " degrees" << endl;
 355       cout << "      Yaw = " << radtodeg*Thruster->GetAnglesToBody(eYaw) << " degrees" << endl;
 356     }
 357   }
 358   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 359     if (from == 0) cout << "Instantiated: FGEngine" << endl;
 360     if (from == 1) cout << "Destroyed:    FGEngine" << endl;
 361   }
 362   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 363   }
 364   if (debug_lvl & 8 ) { // Runtime state variables
 365   }
 366   if (debug_lvl & 16) { // Sanity checking
 367   }
 368   if (debug_lvl & 64) {
 369     if (from == 0) { // Constructor
 370       cout << IdSrc << endl;
 371       cout << IdHdr << endl;
 372     }
 373   }
 374 }
 375 }