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   FuelDensity = 6.0;
  78   unsigned int i;
  79
  80   ResetToIC(); // initialize dynamic terms
  81
  82   FDMExec = exec;
  83   State = FDMExec->GetState();
  84   Atmosphere = FDMExec->GetAtmosphere();
  85   FCS = FDMExec->GetFCS();
  86   Propulsion = FDMExec->GetPropulsion();
  87   Aircraft = FDMExec->GetAircraft();
  88   Propagate = FDMExec->GetPropagate();
  89   Auxiliary = FDMExec->GetAuxiliary();
  90
  91   PropertyManager = FDMExec->GetPropertyManager();
  92
  93   Name = engine_element->GetAttributeValue("name");
  94
  95 // Find and set engine location
  96
  97   local_element = engine_element->GetParent()->FindElement("location");
  98   if (local_element)  location = local_element->FindElementTripletConvertTo("IN");
  99   else      cerr << "No engine location found for this engine." << endl;
 100
 101   local_element = engine_element->GetParent()->FindElement("orient");
 102   if (local_element)  orientation = local_element->FindElementTripletConvertTo("RAD");
 103 //  else          cerr << "No engine orientation found for this engine." << endl;
 104 // Jon: The engine orientation has a default and is not normally used.
 105
 106   SetPlacement(location, orientation);
 107
 108   // Load thruster
 109   local_element = engine_element->GetParent()->FindElement("thruster");
 110   if (local_element) {
 111     if (!LoadThruster(local_element)) exit(-1);
 112   } else {
 113     cerr << "No thruster definition supplied with engine definition." << endl;
 114   }
 115
 116   // Build and initialize the feed tank vector.
 117   for (i=0; i<(Propulsion->GetNumTanks()); i++) {
 118     SourceTanks.push_back(0);
 119   }
 120
 121   // Load feed tank[s] references
 122   local_element = engine_element->GetParent()->FindElement("feed");
 123   if (local_element) {
 124     while (local_element) {
 125       int tankID = (int)local_element->GetDataAsNumber();
 126       FGTank* tank = Propulsion->GetTank(tankID);
 127       AddFeedTank( tankID , tank->GetPriority());
 128       FuelDensity = tank->GetDensity();
 129       local_element = engine_element->GetParent()->FindNextElement("feed");
 130     }
 131   } else {
 132     cerr << "No feed tank specified in engine definition." << endl;
 133   }
 134
 135   string property_name, base_property_name;
 136   base_property_name = CreateIndexedPropertyName("propulsion/engine", EngineNumber);
 137
 138   property_name = base_property_name + "/set-running";
 139   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetRunning, &FGEngine::SetRunning );
 140   property_name = base_property_name + "/thrust-lbs";
 141   PropertyManager->Tie( property_name.c_str(), Thruster, &FGThruster::GetThrust);
 142   property_name = base_property_name + "/fuel-flow-rate-pps";
 143   PropertyManager->Tie( property_name.c_str(), this, &FGEngine::GetFuelFlowRate);
 144
 145   //cout << "Engine[" << EngineNumber << "] using fuel density: " << FuelDensity << endl;
 146
 147   Debug(0);
 148 }
 149
 150 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 151
 152 FGEngine::~FGEngine()
 153 {
 154   delete Thruster;
 155   Debug(1);
 156 }
 157
 158 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 159
 160 void FGEngine::ResetToIC(void)
 161 {
 162   Throttle = 0.0;
 163   Mixture = 1.0;
 164   Starter = false;
 165   FuelExpended = 0.0;
 166   Starved = Running = Cranking = false;
 167   PctPower = 0.0;
 168   TrimMode = false;
 169   FuelFlow_gph = 0.0;
 170   FuelFlow_pph = 0.0;
 171   FuelFreeze = false;
 172 }
 173
 174 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 175 // This base class function should be called from within the
 176 // derived class' Calculate() function before any other calculations are done.
 177 // This base class method removes fuel from the fuel tanks as appropriate,
 178 // and sets the starved flag if necessary.
 179 // This version of the fuel consumption code should never see an oxidizer tank.
 180
 181 void FGEngine::ConsumeFuel(void)
 182 {
 183   if (FuelFreeze) return;
 184   if (TrimMode) return;
 185
 186   unsigned int i;
 187   double Fshortage, FuelNeeded;
 188   FGTank* Tank;
 189   unsigned int TanksWithFuel = 0;
 190   Fshortage = FuelNeeded = 0.0;
 191   double FuelToBurn;
 192   unsigned int CurrentPriority = 1;
 193   vector <int> FeedList;
 194   Starved = false;
 195
 196   FuelToBurn = CalcFuelNeed();
 197   if (FuelToBurn == 0.0) return;
 198
 199   // Count how many fuel tanks with the current priority level have fuel.
 200   // If none, then try next lower priority.  Build the feed list.
 201   while ((TanksWithFuel == 0) && (CurrentPriority <= Propulsion->GetNumTanks())) {
 202     for (i=0; i<Propulsion->GetNumTanks(); i++) {
 203       if (SourceTanks[i] != 0) {
 204         Tank = Propulsion->GetTank(i);
 205         if (Tank->GetType() == FGTank::ttFUEL) {
 206           if ((Tank->GetContents() > 0.0) && ((unsigned int)Tank->GetPriority() == CurrentPriority)) {
 207              ++TanksWithFuel;
 208              FeedList.push_back(i);
 209            }
 210         } else {
 211            cerr << "No oxidizer tanks should be used for this engine type." << endl;
 212         }
 213       }
 214     }
 215     if (TanksWithFuel == 0) CurrentPriority++;
 216   }
 217
 218   // No fuel found at any priority!
 219   if (TanksWithFuel == 0) {
 220     Starved = true;
 221     return;
 222   }
 223
 224   // Remove equal amount of fuel from each feed tank.
 225   FuelNeeded = FuelToBurn/TanksWithFuel;
 226   for (i=0; i<FeedList.size(); i++) {
 227     Tank = Propulsion->GetTank(FeedList[i]);
 228     Tank->Drain(FuelNeeded);
 229   }
 230
 231 }
 232
 233 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 234
 235 double FGEngine::CalcFuelNeed(void)
 236 {
 237   double dT = State->Getdt()*Propulsion->GetRate();
 238   FuelFlowRate = SLFuelFlowMax*PctPower;
 239   FuelExpended = FuelFlowRate*dT;
 240   return FuelExpended;
 241 }
 242
 243 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 244
 245 void FGEngine::SetPlacement(FGColumnVector3& location, FGColumnVector3& orientation)
 246 {
 247   X = location(eX);
 248   Y = location(eY);
 249   Z = location(eZ);
 250   EnginePitch = orientation(ePitch);
 251   EngineYaw = orientation (eYaw);
 252 }
 253
 254 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 255
 256 void FGEngine::AddFeedTank(int tkID, int priority)
 257 {
 258   SourceTanks[tkID] = priority;
 259 }
 260
 261 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 262
 263 FGColumnVector3& FGEngine::GetBodyForces(void)
 264 {
 265   return Thruster->GetBodyForces();
 266 }
 267
 268 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 269
 270 FGColumnVector3& FGEngine::GetMoments(void)
 271 {
 272   return Thruster->GetMoments();
 273 }
 274
 275 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 276
 277 bool FGEngine::LoadThruster(Element *thruster_element)
 278 {
 279   string token, fullpath, localpath;
 280   string thruster_filename, thruster_fullpathname, thrType;
 281   string enginePath = FDMExec->GetEnginePath();
 282   string aircraftPath = FDMExec->GetFullAircraftPath();
 283   ifstream thruster_file;
 284   FGColumnVector3 location, orientation;
 285   string separator = "/";
 286
 287   fullpath = enginePath + separator;
 288   localpath = aircraftPath + separator + "Engines" + separator;
 289
 290   thruster_filename = thruster_element->GetAttributeValue("file");
 291   if ( !thruster_filename.empty()) {
 292     thruster_fullpathname = fullpath + thruster_filename + ".xml";
 293     thruster_file.open(thruster_fullpathname.c_str());
 294     if ( !thruster_file.is_open()) {
 295       thruster_fullpathname = localpath + thruster_filename + ".xml";
 296       thruster_file.open(thruster_fullpathname.c_str());
 297       if ( !thruster_file.is_open()) {
 298         cerr << "Could not open thruster file: " << thruster_filename << ".xml" << endl;
 299         return false;
 300       } else {
 301         thruster_file.close();
 302       }
 303     } else {
 304       thruster_file.close();
 305     }
 306   } else {
 307     cerr << "No thruster filename given." << endl;
 308     return false;
 309   }
 310
 311   document = LoadXMLDocument(thruster_fullpathname);
 312   document->SetParent(thruster_element);
 313
 314   thrType = document->GetName();
 315
 316   if (thrType == "propeller") {
 317     Thruster = new FGPropeller(FDMExec, document, EngineNumber);
 318   } else if (thrType == "nozzle") {
 319     Thruster = new FGNozzle(FDMExec, document, EngineNumber);
 320   } else if (thrType == "direct") {
 321     Thruster = new FGThruster( FDMExec, document, EngineNumber);
 322   }
 323
 324   Thruster->SetdeltaT(State->Getdt() * Propulsion->GetRate());
 325
 326   Debug(2);
 327   return true;
 328 }
 329
 330 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 331 //    The bitmasked value choices are as follows:
 332 //    unset: In this case (the default) JSBSim would only print
 333 //       out the normally expected messages, essentially echoing
 334 //       the config files as they are read. If the environment
 335 //       variable is not set, debug_lvl is set to 1 internally
 336 //    0: This requests JSBSim not to output any messages
 337 //       whatsoever.
 338 //    1: This value explicity requests the normal JSBSim
 339 //       startup messages
 340 //    2: This value asks for a message to be printed out when
 341 //       a class is instantiated
 342 //    4: When this value is set, a message is displayed when a
 343 //       FGModel object executes its Run() method
 344 //    8: When this value is set, various runtime state variables
 345 //       are printed out periodically
 346 //    16: When set various parameters are sanity checked and
 347 //       a message is printed out when they go out of bounds
 348
 349 void FGEngine::Debug(int from)
 350 {
 351   if (debug_lvl <= 0) return;
 352
 353   if (debug_lvl & 1) { // Standard console startup message output
 354     if (from == 0) { // Constructor
 355
 356     }
 357     if (from == 2) { // After thruster loading
 358       cout << "      X = " << Thruster->GetLocationX() << endl;
 359       cout << "      Y = " << Thruster->GetLocationY() << endl;
 360       cout << "      Z = " << Thruster->GetLocationZ() << endl;
 361       cout << "      Pitch = " << radtodeg*Thruster->GetAnglesToBody(ePitch) << " degrees" << endl;
 362       cout << "      Yaw = " << radtodeg*Thruster->GetAnglesToBody(eYaw) << " degrees" << endl;
 363     }
 364   }
 365   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 366     if (from == 0) cout << "Instantiated: FGEngine" << endl;
 367     if (from == 1) cout << "Destroyed:    FGEngine" << endl;
 368   }
 369   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 370   }
 371   if (debug_lvl & 8 ) { // Runtime state variables
 372   }
 373   if (debug_lvl & 16) { // Sanity checking
 374   }
 375   if (debug_lvl & 64) {
 376     if (from == 0) { // Constructor
 377       cout << IdSrc << endl;
 378       cout << IdHdr << endl;
 379     }
 380   }
 381 }
 382 }