Manages the external and/or arbitrary forces. More...

#include <FGExternalReactions.h>

Inheritance diagram for FGExternalReactions:

Collaboration diagram for FGExternalReactions:

Public Member Functions
	FGExternalReactions (FGFDMExec *fdmex)
	Constructor. More...

	~FGExternalReactions (void)
	Destructor. More...

const FGColumnVector3 &	GetForces (void) const
	Retrieves the total forces defined in the external reactions. More...

double	GetForces (int idx) const

const FGColumnVector3 &	GetMoments (void) const
	Retrieves the total moment resulting from the forces defined in the external reactions. More...

double	GetMoments (int idx) const

bool	InitModel (void)

bool	Load (Element *el)
	Loads the external forces from the XML configuration file. More...

bool	Run (bool Holding)
	Sum all the constituent forces for this cycle. More...

Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.

virtual	~FGModel ()
	Destructor.

virtual SGPath	FindFullPathName (const SGPath &path) const

FGFDMExec *	GetExec (void)

unsigned int	GetRate (void)
	Get the output rate for the model in frames.

void	SetPropertyManager (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...

FGFunction *	GetPreFunction (const std::string &name)
	Get one of the "pre" function. More...

bool	Load (Element el, FGPropertyManager PropertyManager, std::string prefix="")

void	PostLoad (Element el, FGPropertyManager PropertyManager, std::string prefix="")

void	PreLoad (Element el, FGPropertyManager PropertyManager, 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.

std::string	GetVersion (void)
	Returns the version number of JSBSim. More...

void	PutMessage (const Message &msg)
	Places a Message structure on the Message queue. More...

void	PutMessage (const std::string &text)
	Creates a message with the given text and places it on the queue. More...

void	PutMessage (const std::string &text, bool bVal)
	Creates a message with the given text and boolean value and places it on the queue. More...

void	PutMessage (const std::string &text, int iVal)
	Creates a message with the given text and integer value and places it on the queue. More...

void	PutMessage (const std::string &text, double dVal)
	Creates a message with the given text and double value and places it on the queue. More...

int	SomeMessages (void)
	Reads the message on the queue (but does not delete it). More...

void	ProcessMessage (void)
	Reads the message on the queue and removes it from the queue. More...

Message *	ProcessNextMessage (void)
	Reads the next message on the queue and removes it from the queue. More...

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 double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit. More...

static double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin. More...

static double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine. More...

static double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.

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 double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius. More...

static double	FeetToMeters (double measure)
	Converts from feet to meters. More...

static double	GaussianRandomNumber (void)

static double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius. More...

static double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit. More...

static double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine. More...

static double	MachFromVcalibrated (double vcas, double p, double psl, double rhosl)
	Calculate the Mach number from the calibrated airspeed. More...

static double	PitotTotalPressure (double mach, double p)
	Compute the total pressure in front of the Pitot tube. More...

static double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius. More...

static double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin. More...

static double	sign (double num)

static double	VcalibratedFromMach (double mach, double p, double psl, double rhosl)
	Calculate the calibrated airspeed from the Mach number. More...

Public Attributes inherited from FGModel
std::string	Name

Static Public Attributes inherited from FGJSBBase
static short	debug_lvl = 1

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

Protected Member Functions inherited from FGJSBBase
void	Debug (int)

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

FGPropertyManager *	PropertyManager

unsigned int	rate

Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties

std::vector< FGFunction * >	PostFunctions

std::vector< FGFunction * >	PreFunctions

Static Protected Attributes inherited from FGJSBBase
static const double	degtorad = 0.017453292519943295769236907684886

static const double	fpstokts = 1.0/ktstofps

static const double	fttom = 0.3048

static int	gaussian_random_number_phase = 0

static const double	hptoftlbssec = 550.0

static const double	in3tom3 = 1.638706E-5

static const double	inchtoft = 0.08333333

static const double	inhgtopa = 3386.38

static const std::string	JSBSim_version = "1.0 " __DATE__ " " __TIME__

static const double	kgtolb = 2.20462

static const double	kgtoslug = 0.06852168

static const double	ktstofps = 1.68781

static const double	lbtoslug = 1.0/slugtolb

static Message	localMsg

static const double	m3toft3 = 1.0/(fttomfttomfttom)

static double	Mair = 28.9645

static unsigned int	messageId = 0

static std::queue< Message >	Messages

static const std::string	needed_cfg_version = "2.0"

static const double	psftoinhg = 0.014138

static const double	psftopa = 47.88

static const double	radtodeg = 57.295779513082320876798154814105

static double	Reng = 1716.56

static double	Rstar = 1545.348

static const double	SHRatio = 1.40

static const double	slugtolb = 32.174049

Detailed Description

Manages the external and/or arbitrary forces.

The external reactions capability in JSBSim really should be named "arbitrary forces", because this feature can be used to model a wide variety of forces that act on a vehicle. Some examples include: parachutes, catapult, arresting hook, and tow line.

This class acts similarly to the other "manager classes" (FGPropulsion, FGFCS, FGGroundReactions, FGAerodynamics) because it manages collections of constituent forces. The individual forces are implemented with the FGExternalForce class.

The format of the optional external reactions section in the config file is as follows:

<external_reactions>
  <!-- Interface properties, a.k.a. property declarations -->
  <property> ... </property>
    
  <force name="name" frame="BODY | LOCAL | WIND" unit="unit">
    ...
  </force>
  <!-- Additional force definitions may follow -->
  <force name="name" frame="BODY | LOCAL | WIND" unit="unit">
    ...
  </force>
</external_reactions>

See the FGExternalForce class for more information on the format of the force specification itself.

When force elements are encountered in the configuration file, a new instance of the FGExternalForce class is created and a pointer to the class is pushed onto the Forces vector.

This class is one of a few of the manager classes that allows properties to be "declared". In code, these are represented by the interface_properties vector. Properties that have not yet been created in an already parsed section of the configuration file and that are used in the definition of an external force should be declared in the external_reactions section because they will not be created automatically, and so would cause an error, since the property cannot be found to exist.

See the FGExternalForce documentation for details on how forces are actually calculated.

Definition at line 118 of file FGExternalReactions.h.

Constructor & Destructor Documentation

◆ FGExternalReactions()

FGExternalReactions ( FGFDMExec * fdmex )

Constructor.

Parameters

fdmex pointer to the main executive class.

Definition at line 64 of file FGExternalReactions.cpp.

                                                          : FGModel(fdmex)
 {
   NoneDefined = true;
 
   Debug(0);
 }

◆ ~FGExternalReactions()

~FGExternalReactions ( void )

Destructor.

Within the destructor the Forces and interface_properties vectors are cleared out and the items pointed to are deleted.

Definition at line 101 of file FGExternalReactions.cpp.

 {
   for (unsigned int i=0; i<Forces.size(); i++) delete Forces[i];
   Forces.clear();
 
   Debug(1);
 }

Member Function Documentation

◆ GetForces()

const FGColumnVector3& GetForces ( void ) const

inline

Retrieves the total forces defined in the external reactions.

Returns: the total force in pounds.

Definition at line 154 of file FGExternalReactions.h.

154 {return vTotalForces;}

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◆ GetMoments()

const FGColumnVector3& GetMoments ( void ) const

inline

Retrieves the total moment resulting from the forces defined in the external reactions.

Returns: the total moment in foot-pounds.

Definition at line 160 of file FGExternalReactions.h.

160 {return vTotalMoments;}

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◆ Load()

bool Load ( Element * el )

virtual

Loads the external forces from the XML configuration file.

If the external_reactions section is encountered in the vehicle configuration file, this Load() method is called. All external forces will be parsed, and a FGExternalForce object will be instantiated for each force definition.

Parameters

el	a pointer to the XML element holding the external reactions definition.

Reimplemented from FGModel.

Definition at line 73 of file FGExternalReactions.cpp.

 {
   // Call the base class Load() function to load interface properties.
   if (!FGModel::Load(el))
     return false;
 
   Debug(2);
 
   // Parse force elements
 
   int index=0;
   Element* force_element = el->FindElement("force");
   while (force_element) {
     Forces.push_back( new FGExternalForce(FDMExec, force_element, index) );
     NoneDefined = false;
     index++; 
     force_element = el->FindNextElement("force");
   }
 
   PostLoad(el, PropertyManager);
 
   if (!NoneDefined) bind();
 
   return true;
 }

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◆ Run()

bool Run ( bool Holding )

virtual

Sum all the constituent forces for this cycle.

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: true always.

Reimplemented from FGModel.

Definition at line 123 of file FGExternalReactions.cpp.

 {
   if (FGModel::Run(Holding)) return true;
   if (Holding) return false; // if paused don't execute
   if (NoneDefined) return true;
 
   RunPreFunctions();
 
   vTotalForces.InitMatrix();
   vTotalMoments.InitMatrix();
 
   for (unsigned int i=0; i<Forces.size(); i++) {
     vTotalForces  += Forces[i]->GetBodyForces();
     vTotalMoments += Forces[i]->GetMoments();
   }
 
   RunPostFunctions();
 
   return false;
 }

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

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ FGExternalReactions()

◆ ~FGExternalReactions()

Member Function Documentation

◆ GetForces()

◆ GetMoments()

◆ Load()

◆ Run()