FGPropulsion Class Reference

Detailed Description

Propulsion management class.

The Propulsion class is the container for the entire propulsion system, which is comprised of engines, and tanks. Once the Propulsion class gets the config file, it reads in the <propulsion> section. Then:

1. The appropriate engine type instance is created
2. At least one tank object is created, and is linked to an engine.

At Run time each engine's Calculate() method is called.

Configuration File Format:

<propulsion>
    <engine file="{string}">
      ... see FGEngine, FGThruster, and class for engine type ...
    </engine>
    ... more engines ...
    <tank type="{FUEL | OXIDIZER}"> 
      ... see FGTank ...
    </tank>
    ... more tanks ...
    <dump-rate unit="{LBS/MIN | KG/MIN}"> {number} </dump-rate>
    <refuel-rate unit="{LBS/MIN | KG/MIN}"> {number} </refuel-rate>
</propulsion>

Author

Jon S. Berndt

See also

FGEngine FGTank

Definition at line 98 of file FGPropulsion.h.

#include <FGPropulsion.h>

Inheritance diagram for FGPropulsion:

Collaboration diagram for FGPropulsion:

Public Member Functions
	FGPropulsion (FGFDMExec *)
	Constructor.
	~FGPropulsion () override
	Destructor.
const FGMatrix33 &	CalculateTankInertias (void)
void	DoRefuel (double time_slice)
void	DumpFuel (double time_slice)
SGPath	FindFullPathName (const SGPath &path) const override
int	GetActiveEngine (void) const
int	GetCutoff (void) const
auto	GetEngine (unsigned int index) const
	Retrieves an engine object pointer from the list of engines. More...
double	GetForces (int n) const
const FGColumnVector3 &	GetForces (void) const
bool	GetFuelFreeze (void) const
double	GetMoments (int n) const
const FGColumnVector3 &	GetMoments (void) const
size_t	GetNumEngines (void) const
	Retrieves the number of engines defined for the aircraft.
size_t	GetNumTanks (void) const
	Retrieves the number of tanks defined for the aircraft.
std::string	GetPropulsionStrings (const std::string &delimiter) const
std::string	GetPropulsionTankReport ()
std::string	GetPropulsionValues (const std::string &delimiter) const
int	GetStarter (void) const
bool	GetSteadyState (void)
	Loops the engines until thrust output steady (used for trimming)
auto	GetTank (unsigned int index) const
	Retrieves a tank object pointer from the list of tanks. More...
const FGColumnVector3 &	GetTanksMoment (void)
double	GetTanksWeight (void) const
bool	InitModel (void) override
void	InitRunning (int n)
	Sets up the engines as running.
bool	Load (Element *el) override
	Loads the propulsion system (engine[s] and tank[s]). More...
bool	Run (bool Holding) override
	Executes the propulsion model. More...
void	SetActiveEngine (int engine)
void	SetCutoff (int setting=0)
void	SetFuelFreeze (bool f)
void	SetMagnetos (int setting)
void	SetStarter (int setting)
double	Transfer (int source, int target, double amount)
Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.
	~FGModel () override
	Destructor.
FGFDMExec *	GetExec (void)
const std::string &	GetName (void)
unsigned int	GetRate (void)
	Get the output rate for the model in frames.
void	SetPropertyManager (std::shared_ptr< FGPropertyManager > fgpm)
void	SetRate (unsigned int tt)
	Set the ouput rate for the model in frames.
Public Member Functions inherited from FGModelFunctions
std::string	GetFunctionStrings (const std::string &delimeter) const
	Gets the strings for the current set of functions. More...
std::string	GetFunctionValues (const std::string &delimeter) const
	Gets the function values. More...
std::shared_ptr< FGFunction >	GetPreFunction (const std::string &name)
	Get one of the "pre" function. More...
bool	Load (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	PostLoad (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	PreLoad (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	RunPostFunctions (void)
void	RunPreFunctions (void)
Public Member Functions inherited from FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.
virtual	~FGJSBBase ()
	Destructor for FGJSBBase.
void	disableHighLighting (void)
	Disables highlighting in the console output.

Public Attributes
struct FGEngine::Inputs	in

Additional Inherited Members
Public Types inherited from FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N.
enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R.
enum	{ eU = 1 , eV , eW }
	Velocities U, V, W.
enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z.
enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi.
enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift.
enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw.
enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down.
enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude.
enum	{   inNone = 0 , inDegrees , inRadians , inMeters ,   inFeet }
	Conversion specifiers.
Static Public Member Functions inherited from FGJSBBase
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim. More...
static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit. More...
static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine. More...
static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius. More...
static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine. More...
static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin. More...
static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius. More...
static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit. More...
static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin. More...
static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius. More...
static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters. More...
static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison. More...
static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison. More...
static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison. More...
static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison. More...
static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.
static constexpr double	sign (double num)
Static Public Attributes inherited from FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text
static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text
static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text
static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties
static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text
static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off
static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text
static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text
static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text
static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text
static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text
static short	debug_lvl = 1
Protected Member Functions inherited from FGModel
bool	Upload (Element *el, bool preLoad)
	Uploads this model in memory. More...
Static Protected Member Functions inherited from FGJSBBase
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)
Protected Attributes inherited from FGModel
unsigned int	exe_ctr
FGFDMExec *	FDMExec
std::string	Name
std::shared_ptr< FGPropertyManager >	PropertyManager
unsigned int	rate
Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties
std::vector< std::shared_ptr< FGFunction > >	PostFunctions
std::vector< std::shared_ptr< FGFunction > >	PreFunctions
Static Protected Attributes inherited from FGJSBBase
static constexpr double	radtodeg = 180. / M_PI
static constexpr double	degtorad = M_PI / 180.
static constexpr double	hptoftlbssec = 550.0
static constexpr double	psftoinhg = 0.014138
static constexpr double	psftopa = 47.88
static constexpr double	fttom = 0.3048
static constexpr double	ktstofps = 1852./(3600*fttom)
static constexpr double	fpstokts = 1.0 / ktstofps
static constexpr double	inchtoft = 1.0/12.0
static constexpr double	m3toft3 = 1.0/(fttom*fttom*fttom)
static constexpr double	in3tom3 = inchtoft*inchtoft*inchtoft/m3toft3
static constexpr double	inhgtopa = 3386.38
static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff. More...
static constexpr double	lbtoslug = 1.0/slugtolb
static constexpr double	kgtolb = 2.20462
static constexpr double	kgtoslug = 0.06852168
static const std::string	needed_cfg_version = "2.0"
static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__

Member Function Documentation

GetEngine()

auto GetEngine ( unsigned int  index ) const

inline

Retrieves an engine object pointer from the list of engines.

Parameters

index

the engine index within the vector container

Returns

the address of the specific engine, or zero if no such engine is available

Definition at line 132 of file FGPropulsion.h.

                                           {
    assert(index < Engines.size());
    return Engines[index];
  }

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GetTank()

auto GetTank ( unsigned int  index ) const

inline

Retrieves a tank object pointer from the list of tanks.

Parameters

index

the tank index within the vector container

Returns

the address of the specific tank, or zero if no such tank is available

Definition at line 144 of file FGPropulsion.h.

                                         {
    assert(index < Tanks.size());
    return Tanks[index];
  }

Load()

bool Load ( Element *  el )

overridevirtual

Loads the propulsion system (engine[s] and tank[s]).

Characteristics of the propulsion system are read in from the config file.

Parameters

el	pointer to an XML element that contains the engine information.

Returns

true if successfully loaded, otherwise false

Reimplemented from FGModel.

Definition at line 343 of file FGPropulsion.cpp.

{
  FGModelLoader ModelLoader(this);
 
  Debug(2);
  ReadingEngine = false;
  double FuelDensity = 6.0;
 
  Name = "Propulsion Model: " + el->GetAttributeValue("name");
 
  // Perform base class Pre-Load
  if (!FGModel::Upload(el, true))
    return false;
 
  // Process tank definitions first to establish the number of fuel tanks
 
  Element* tank_element = el->FindElement("tank");
  unsigned int numTanks = 0;
 
  while (tank_element) {
    Tanks.push_back(make_shared<FGTank>(FDMExec, tank_element, numTanks));
    const auto& tank = Tanks.back();
    if (tank->GetType() == FGTank::ttFUEL)
      FuelDensity = tank->GetDensity();
    else if (tank->GetType() != FGTank::ttOXIDIZER) {
      cerr << "Unknown tank type specified." << endl;
      return false;
    }
    numTanks++;
    tank_element = el->FindNextElement("tank");
  }
 
  ReadingEngine = true;
  Element* engine_element = el->FindElement("engine");
  unsigned int numEngines = 0;
 
  while (engine_element) {
    if (!ModelLoader.Open(engine_element)) return false;
 
    try {
      // Locate the thruster definition
      Element* thruster_element = engine_element->FindElement("thruster");
      if (!thruster_element || !ModelLoader.Open(thruster_element))
        throw("No thruster definition supplied with engine definition.");
 
      if (engine_element->FindElement("piston_engine")) {
        Element *element = engine_element->FindElement("piston_engine");
        Engines.push_back(make_shared<FGPiston>(FDMExec, element, numEngines, in));
      } else if (engine_element->FindElement("turbine_engine")) {
        Element *element = engine_element->FindElement("turbine_engine");
        Engines.push_back(make_shared<FGTurbine>(FDMExec, element, numEngines, in));
      } else if (engine_element->FindElement("turboprop_engine")) {
        Element *element = engine_element->FindElement("turboprop_engine");
        Engines.push_back(make_shared<FGTurboProp>(FDMExec, element, numEngines, in));
      } else if (engine_element->FindElement("rocket_engine")) {
        Element *element = engine_element->FindElement("rocket_engine");
        Engines.push_back(make_shared<FGRocket>(FDMExec, element, numEngines, in));
      } else if (engine_element->FindElement("electric_engine")) {
        Element *element = engine_element->FindElement("electric_engine");
        Engines.push_back(make_shared<FGElectric>(FDMExec, element, numEngines, in));
      } else if (engine_element->FindElement("brushless_dc_motor")) {
        Element *element = engine_element->FindElement("brushless_dc_motor");
        Engines.push_back(make_shared<FGBrushLessDCMotor>(FDMExec, element, numEngines, in));
      }
      else {
        cerr << engine_element->ReadFrom() << " Unknown engine type" << endl;
        return false;
      }
    } catch (std::string& str) {
      cerr << endl << fgred << str << reset << endl;
      return false;
    }
 
    numEngines++;
 
    engine_element = el->FindNextElement("engine");
  }
 
  if (numEngines) bind();
 
  CalculateTankInertias();
 
  if (el->FindElement("dump-rate"))
    DumpRate = el->FindElementValueAsNumberConvertTo("dump-rate", "LBS/MIN");
  if (el->FindElement("refuel-rate"))
    RefuelRate = el->FindElementValueAsNumberConvertTo("refuel-rate", "LBS/MIN");
 
  for (auto& engine: Engines)
    engine->SetFuelDensity(FuelDensity);
 
  PostLoad(el, FDMExec);
 
  return true;
}

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Run()

bool Run ( bool  Holding )

overridevirtual

Executes the propulsion model.

The initial plan for the FGPropulsion class calls for Run() to be executed, calculating the power available from the engine. Can pass in a value indicating if the executive is directing the simulation to Hold.

Parameters

Holding

if true, the executive has been directed to hold the sim from advancing time. Some models may ignore this flag, such as the Input model, which may need to be active to listen on a socket for the "Resume" command to be given.

Returns

false if no error

Reimplemented from FGModel.

Definition at line 116 of file FGPropulsion.cpp.

{
  if (FGModel::Run(Holding)) return true;
  if (Holding) return false;
 
  RunPreFunctions();
 
  vForces.InitMatrix();
  vMoments.InitMatrix();
 
  for (auto& engine: Engines) {
    engine->Calculate();
    ConsumeFuel(engine.get());
    vForces  += engine->GetBodyForces();  // sum body frame forces
    vMoments += engine->GetMoments();     // sum body frame moments
  }
 
  TotalFuelQuantity = 0.0;
  TotalOxidizerQuantity = 0.0;
  for (auto& tank: Tanks) {
    tank->Calculate( in.TotalDeltaT, in.TAT_c);
    switch (tank->GetType()) {
    case FGTank::ttFUEL:
      TotalFuelQuantity += tank->GetContents();
      break;
    case FGTank::ttOXIDIZER:
      TotalOxidizerQuantity += tank->GetContents();
      break;
    default:
      break;
    }
  }
 
  if (refuel) DoRefuel( in.TotalDeltaT );
  if (dump) DumpFuel( in.TotalDeltaT );
 
  RunPostFunctions();
 
  return false;
}

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The documentation for this class was generated from the following files:

• FGPropulsion.h
• FGPropulsion.cpp