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 "FGState.h"
  45 #include "models/FGPropulsion.h"
  46 #include "input_output/FGXMLParse.h"
  47 #include "math/FGColumnVector3.h"
  48
  49 #include <iostream>
  50 #include <fstream>
  51 #include <cstdlib>
  52
  53 using namespace std;
  54
  55 namespace JSBSim {
  56
  57 static const char *IdSrc = "$Id$";
  58 static const char *IdHdr = ID_ENGINE;
  59
  60 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  61 CLASS IMPLEMENTATION
  62 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  63
  64 FGEngine::FGEngine(FGFDMExec* exec, Element* engine_element, int engine_number)
  65                       : EngineNumber(engine_number)
  66 {
  67   Element* local_element;
  68   FGColumnVector3 location, orientation;
  69
  70   Name = "";
  71   Type = etUnknown;
  72   X = Y = Z = 0.0;
  73   EnginePitch = EngineYaw = 0.0;
  74   SLFuelFlowMax = 0.0;
  75   MaxThrottle = 1.0;
  76   MinThrottle = 0.0;
  77   unsigned int i;
  78
  79   ResetToIC(); // initialize dynamic terms
  80
  81   FDMExec = exec;
  82   State = FDMExec->GetState();
  83   Atmosphere = FDMExec->GetAtmosphere();
  84   FCS = FDMExec->GetFCS();
  85   Propulsion = FDMExec->GetPropulsion();
  86   Aircraft = FDMExec->GetAircraft();
  87   Propagate = FDMExec->GetPropagate();
  88   Auxiliary = FDMExec->GetAuxiliary();
  89
  90   PropertyManager = FDMExec->GetPropertyManager();
  91
  92   Name = engine_element->GetAttributeValue("name");
  93
  94 // Find and set engine location
  95
  96   local_element = engine_element->GetParent()->FindElement("location");
  97   if (local_element)  location = local_element->FindElementTripletConvertTo("IN");
  98   else      cerr << "No engine location found for this engine." << endl;
  99
 100   local_element = engine_element->GetParent()->FindElement("orient");
 101   if (local_element)  orientation = local_element->FindElementTripletConvertTo("RAD");
 102 //  else          cerr << "No engine orientation found for this engine." << endl;
 103 // Jon: The engine orientation has a default and is not normally used.
 104
 105   SetPlacement(location, orientation);
 106
 107   // Load thruster
 108   local_element = engine_element->GetParent()->FindElement("thruster");
 109   if (local_element) {
 110     if (!LoadThruster(local_element)) exit(-1);
 111   } else {
 112     cerr << "No thruster definition supplied with engine definition." << endl;
 113   }
 114
 115   // Build and initialize the feed tank vector.
 116   for (i=0; i<(Propulsion->GetNumTanks()); i++) {
 117     SourceTanks.push_back(0);
 118   }
 119
 120   // Load feed tank[s] references
 121   local_element = engine_element->GetParent()->FindElement("feed");
 122   if (local_element) {
 123     while (local_element) {
 124       int tankID = (int)local_element->GetDataAsNumber();
 125       AddFeedTank( tankID , Propulsion->GetTank(tankID)->GetPriority());
 126       local_element = engine_element->GetParent()->FindNextElement("feed");
 127     }
 128   } else {
 129     cerr << "No feed tank specified in engine definition." << endl;
 130   }
 131
 132   string property_name, base_property_name;
 133   base_property_name = CreateIndexedPropertyName("propulsion/engine", EngineNumber);
 134
 135   property_name = base_property_name + "/set-running";
 136   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetRunning, &FGEngine::SetRunning );
 137   property_name = base_property_name + "/thrust-lbs";
 138   PropertyManager->Tie( property_name.c_str(), Thruster, &FGThruster::GetThrust);
 139   property_name = base_property_name + "/fuel-flow-rate-pps";
 140   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetFuelFlowRate);
 141
 142   Debug(0);
 143 }
 144
 145 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 146
 147 FGEngine::~FGEngine()
 148 {
 149   delete Thruster;
 150   Debug(1);
 151 }
 152
 153 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 154
 155 void FGEngine::ResetToIC(void)
 156 {
 157   Throttle = 0.0;
 158   Mixture = 1.0;
 159   Starter = false;
 160   FuelExpended = 0.0;
 161   Starved = Running = Cranking = false;
 162   PctPower = 0.0;
 163   TrimMode = false;
 164   FuelFlow_gph = 0.0;
 165   FuelFlow_pph = 0.0;
 166   FuelFreeze = false;
 167 }
 168
 169 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 170 // This base class function should be called from within the
 171 // derived class' Calculate() function before any other calculations are done.
 172 // This base class method removes fuel from the fuel tanks as appropriate,
 173 // and sets the starved flag if necessary.
 174 // This version of the fuel consumption code should never see an oxidizer tank.
 175
 176 void FGEngine::ConsumeFuel(void)
 177 {
 178   if (FuelFreeze) return;
 179   if (TrimMode) return;
 180
 181   unsigned int i;
 182   double Fshortage, FuelNeeded;
 183   FGTank* Tank;
 184   unsigned int TanksWithFuel = 0;
 185   Fshortage = FuelNeeded = 0.0;
 186   double FuelToBurn;
 187   unsigned int CurrentPriority = 1;
 188   vector <int> FeedList;
 189   Starved = false;
 190
 191   FuelToBurn = CalcFuelNeed();
 192   if (FuelToBurn == 0.0) return;
 193
 194   // Count how many fuel tanks with the current priority level have fuel.
 195   // If none, then try next lower priority.  Build the feed list.
 196   while ((TanksWithFuel == 0) && (CurrentPriority <= Propulsion->GetNumTanks())) {
 197     for (i=0; i<Propulsion->GetNumTanks(); i++) {
 198       if (SourceTanks[i] != 0) {
 199         Tank = Propulsion->GetTank(i);
 200         if (Tank->GetType() == FGTank::ttFUEL) {
 201           if ((Tank->GetContents() > 0.0) && ((unsigned int)Tank->GetPriority() == CurrentPriority)) {
 202              ++TanksWithFuel;
 203              FeedList.push_back(i);
 204            }
 205         } else {
 206            cerr << "No oxidizer tanks should be used for this engine type." << endl;
 207         }
 208       }
 209     }
 210     if (TanksWithFuel == 0) CurrentPriority++;
 211   }
 212
 213   // No fuel found at any priority!
 214   if (TanksWithFuel == 0) {
 215     Starved = true;
 216     return;
 217   }
 218
 219   // Remove equal amount of fuel from each feed tank.
 220   FuelNeeded = FuelToBurn/TanksWithFuel;
 221   for (i=0; i<FeedList.size(); i++) {
 222     Tank = Propulsion->GetTank(FeedList[i]);
 223     Tank->Drain(FuelNeeded);
 224   }
 225
 226 }
 227
 228 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 229
 230 double FGEngine::CalcFuelNeed(void)
 231 {
 232   double dT = State->Getdt()*Propulsion->GetRate();
 233   FuelFlowRate = SLFuelFlowMax*PctPower;
 234   FuelExpended = FuelFlowRate*dT;
 235   return FuelExpended;
 236 }
 237
 238 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 239
 240 void FGEngine::SetPlacement(FGColumnVector3& location, FGColumnVector3& orientation)
 241 {
 242   X = location(eX);
 243   Y = location(eY);
 244   Z = location(eZ);
 245   EnginePitch = orientation(ePitch);
 246   EngineYaw = orientation (eYaw);
 247 }
 248
 249 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 250
 251 void FGEngine::AddFeedTank(int tkID, int priority)
 252 {
 253   SourceTanks[tkID] = priority;
 254 }
 255
 256 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 257
 258 FGColumnVector3& FGEngine::GetBodyForces(void)
 259 {
 260   return Thruster->GetBodyForces();
 261 }
 262
 263 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 264
 265 FGColumnVector3& FGEngine::GetMoments(void)
 266 {
 267   return Thruster->GetMoments();
 268 }
 269
 270 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 271
 272 bool FGEngine::LoadThruster(Element *thruster_element)
 273 {
 274   string token, fullpath, localpath;
 275   string thruster_filename, thruster_fullpathname, thrType;
 276   string enginePath = FDMExec->GetEnginePath();
 277   string aircraftPath = FDMExec->GetFullAircraftPath();
 278   ifstream thruster_file;
 279   FGColumnVector3 location, orientation;
 280   string separator = "/";
 281
 282   fullpath = enginePath + separator;
 283   localpath = aircraftPath + separator + "Engines" + separator;
 284
 285   thruster_filename = thruster_element->GetAttributeValue("file");
 286   if ( !thruster_filename.empty()) {
 287     thruster_fullpathname = fullpath + thruster_filename + ".xml";
 288     thruster_file.open(thruster_fullpathname.c_str());
 289     if ( !thruster_file.is_open()) {
 290       thruster_fullpathname = localpath + thruster_filename + ".xml";
 291       thruster_file.open(thruster_fullpathname.c_str());
 292       if ( !thruster_file.is_open()) {
 293         cerr << "Could not open thruster file: " << thruster_filename << ".xml" << endl;
 294         return false;
 295       } else {
 296         thruster_file.close();
 297       }
 298     } else {
 299       thruster_file.close();
 300     }
 301   } else {
 302     cerr << "No thruster filename given." << endl;
 303     return false;
 304   }
 305
 306   document = LoadXMLDocument(thruster_fullpathname);
 307   document->SetParent(thruster_element);
 308
 309   thrType = document->GetName();
 310
 311   if (thrType == "propeller") {
 312     Thruster = new FGPropeller(FDMExec, document, EngineNumber);
 313   } else if (thrType == "nozzle") {
 314     Thruster = new FGNozzle(FDMExec, document, EngineNumber);
 315   } else if (thrType == "direct") {
 316     Thruster = new FGThruster( FDMExec, document, EngineNumber);
 317   }
 318
 319   Thruster->SetdeltaT(State->Getdt() * Propulsion->GetRate());
 320
 321   Debug(2);
 322   return true;
 323 }
 324
 325 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 326 //    The bitmasked value choices are as follows:
 327 //    unset: In this case (the default) JSBSim would only print
 328 //       out the normally expected messages, essentially echoing
 329 //       the config files as they are read. If the environment
 330 //       variable is not set, debug_lvl is set to 1 internally
 331 //    0: This requests JSBSim not to output any messages
 332 //       whatsoever.
 333 //    1: This value explicity requests the normal JSBSim
 334 //       startup messages
 335 //    2: This value asks for a message to be printed out when
 336 //       a class is instantiated
 337 //    4: When this value is set, a message is displayed when a
 338 //       FGModel object executes its Run() method
 339 //    8: When this value is set, various runtime state variables
 340 //       are printed out periodically
 341 //    16: When set various parameters are sanity checked and
 342 //       a message is printed out when they go out of bounds
 343
 344 void FGEngine::Debug(int from)
 345 {
 346   if (debug_lvl <= 0) return;
 347
 348   if (debug_lvl & 1) { // Standard console startup message output
 349     if (from == 0) { // Constructor
 350
 351     }
 352     if (from == 2) { // After thruster loading
 353       cout << "      X = " << Thruster->GetLocationX() << endl;
 354       cout << "      Y = " << Thruster->GetLocationY() << endl;
 355       cout << "      Z = " << Thruster->GetLocationZ() << endl;
 356       cout << "      Pitch = " << radtodeg*Thruster->GetAnglesToBody(ePitch) << " degrees" << endl;
 357       cout << "      Yaw = " << radtodeg*Thruster->GetAnglesToBody(eYaw) << " degrees" << endl;
 358     }
 359   }
 360   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 361     if (from == 0) cout << "Instantiated: FGEngine" << endl;
 362     if (from == 1) cout << "Destroyed:    FGEngine" << endl;
 363   }
 364   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 365   }
 366   if (debug_lvl & 8 ) { // Runtime state variables
 367   }
 368   if (debug_lvl & 16) { // Sanity checking
 369   }
 370   if (debug_lvl & 64) {
 371     if (from == 0) { // Constructor
 372       cout << IdSrc << endl;
 373       cout << IdHdr << endl;
 374     }
 375   }
 376 }
 377 }