FGTransmission Class Reference

Utility class that handles power transmission in conjunction with FGRotor. More...

#include <FGTransmission.h>

Inheritance diagram for FGTransmission:

Collaboration diagram for FGTransmission:

Public Member Functions
	FGTransmission (FGFDMExec *exec, int num, double dt)
	Constructor for FGTransmission. More...
	~FGTransmission ()
	Destructor for FGTransmission.
void	Calculate (double EnginePower, double ThrusterTorque, double dt)
double	GetBrakeCtrlNorm () const
double	GetClutchCtrlNorm () const
double	GetEngineFriction () const
double	GetEngineMoment () const
double	GetEngineRPM ()
double	GetFreeWheelTransmission () const
double	GetMaxBrakePower () const
double	GetThrusterMoment () const
double	GetThrusterRPM ()
void	SetBrakeCtrlNorm (double x)
void	SetClutchCtrlNorm (double x)
void	SetEngineFriction (double x)
void	SetEngineMoment (double x)
void	SetEngineRPM (double x)
void	SetMaxBrakePower (double x)
void	SetThrusterMoment (double x)
void	SetThrusterRPM (double x)
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...
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)
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/(fttom*fttom*fttom)
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

Utility class that handles power transmission in conjunction with FGRotor.

This class provides brake, clutch and free-wheel-unit (FWU) functionality for the rotor model. Also it is responsible for the RPM calculations.

When the engine is off the brake could be used to slow/hold down a spinning rotor. The maximum brake power is defined in the rotors' config file. (Right now there is no checking if the input is in the [0..1] range.)

The clutch operation is based on a heuristic approach. In the intermediate state the transfer is proportional to the clutch position. But equal RPM values are enforced on the thruster and rotor sides when approaching the closed state.

The FWU inhibits that the rotor is driving the engine. To do so, the code just predicts the upcoming FWU state based on current torque conditions.

Some engines won't work properly when the clutch is open. To keep them controllable some load must be provided on the engine side (EngineFriction, aka gear-loss). See the notes under 'Engine issues' in FGRotor.

Property tree

The following properties are created (with x = your thruster number):

    propulsion/engine[x]/brake-ctrl-norm
    propulsion/engine[x]/free-wheel-transmission
    propulsion/engine[x]/clutch-ctrl-norm
  

Notes

• EngineFriction is assumed constant, so better orientate at low RPM values, because piston and turboprop engines don't 'like' high load at startup.
• The model doesn't support backward operation.
• And even worse, the torque calculations silently assume a minimal RPM value of approx. 1.

Definition at line 114 of file FGTransmission.h.

Constructor & Destructor Documentation

FGTransmission()

FGTransmission	(	FGFDMExec *	exec,
		int	num,
		double	dt
	)

Constructor for FGTransmission.

Parameters

exec	a pointer to the main executive object
num	the number of the thruster that uses this object
dt	simulation delta T

Definition at line 58 of file FGTransmission.cpp.

                                                                  :
  FreeWheelTransmission(1.0),
  ThrusterMoment(1.0), EngineMoment(1.0), EngineFriction(0.0),
  ClutchCtrlNorm(1.0), BrakeCtrlNorm(0.0), MaxBrakePower(0.0),
  EngineRPM(0.0), ThrusterRPM(0.0)
{
  PropertyManager = exec->GetPropertyManager();
  FreeWheelLag = Filter(200.0,dt); // avoid too abrupt changes in transmission
  BindModel(num);
}

Here is the call graph for this function:

---

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

• FGTransmission.h
• FGTransmission.cpp