Handles the calculation of accelerations. More...

#include <FGAccelerations.h>

Inheritance diagram for FGAccelerations:

Collaboration diagram for FGAccelerations:

Classes
struct	Inputs

Public Types
enum	eGravType { gtStandard, gtWGS84 }
	These define the indices use to select the gravitation models. More...

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.

Public Member Functions
	FGAccelerations (FGFDMExec *Executive)
	Constructor. More...

	~FGAccelerations ()
	Destructor.

const FGColumnVector3 &	GetBodyAccel (void) const
	Retrieves the acceleration resulting from the applied forces. More...

double	GetBodyAccel (int idx) const
	Retrieves a component of the acceleration resulting from the applied forces. More...

double	GetForces (int idx) const
	Retrieves the total forces applied on the body. More...

FGColumnVector3	GetForces (void) const

const FGColumnVector3 &	GetGravAccel (void) const

double	GetGravAccelMagnitude (void) const

double	GetGroundForces (int idx) const
	Retrieves the ground forces applied on the body. More...

FGColumnVector3	GetGroundForces (void) const

double	GetGroundMoments (int idx) const
	Retrieves the ground moments applied on the body. More...

FGColumnVector3	GetGroundMoments (void) const

double	GetMoments (int idx) const
	Retrieves a component of the total moments applied on the body. More...

FGColumnVector3	GetMoments (void) const

const FGColumnVector3 &	GetPQRdot (void) const
	Retrieves the body axis angular acceleration vector. More...

double	GetPQRdot (int axis) const
	Retrieves a body frame angular acceleration component. More...

const FGColumnVector3 &	GetPQRidot (void) const
	Retrieves the axis angular acceleration vector in the ECI frame. More...

const FGColumnVector3 &	GetUVWdot (void) const
	Retrieves the body axis acceleration. More...

double	GetUVWdot (int idx) const
	Retrieves a body frame acceleration component. More...

const FGColumnVector3 &	GetUVWidot (void) const
	Retrieves the body axis acceleration in the ECI frame. More...

double	GetWeight (int idx) const
	Retrieves the weight applied on the body. More...

FGColumnVector3	GetWeight (void) const

void	InitializeDerivatives (void)
	Initializes the FGAccelerations class prior to a new execution. More...

bool	InitModel (void)
	Initializes the FGAccelerations class after instantiation and prior to first execution. More...

bool	Run (bool Holding)
	Runs the state propagation model; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold. More...

void	SetHoldDown (bool hd)
	Sets the property forces/hold-down. 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...

Public Attributes
struct JSBSim::FGAccelerations::Inputs	in

Public Attributes inherited from FGModel
std::string	Name

Additional Inherited Members
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 FGModel
virtual bool	Load (Element *el)
	Loads this model. More...

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

Handles the calculation of accelerations.

Calculate the angular accelerations
Calculate the translational accelerations
Calculate the angular rate
Calculate the translational velocity

This class is collecting all the forces and the moments acting on the body to calculate the corresponding accelerations according to Newton's second law. This is also where the friction forces related to the ground reactions are evaluated.

JSBSim provides several ways to calculate the influence of the gravity on the vehicle. The different options can be selected via the following properties :

simulation/gravity-model (read/write) Selects the gravity model. Two options are available : 0 (Standard gravity assuming the Earth is spherical) or 1 (WGS84 gravity taking the Earth oblateness into account). WGS84 gravity is the default.
simulation/gravitational-torque (read/write) Enables/disables the calculations of the gravitational torque on the vehicle. This is mainly relevant for spacecrafts that are orbiting at low altitudes. Gravitational torque calculations are disabled by default.

Special care is taken in the calculations to obtain maximum fidelity in JSBSim results. In FGAccelerations, this is obtained by avoiding as much as possible the transformations from one frame to another. As a consequence, the frames in which the accelerations are primarily evaluated are dictated by the frames in which FGPropagate resolves the equations of movement (the ECI frame for the translations and the body frame for the rotations).

See also: Mark Harris and Robert Lyle, "Spacecraft Gravitational Torques", NASA SP-8024, May 1969

Author: Jon S. Berndt, Mathias Froehlich, Bertrand Coconnier

Version

Id: FGAccelerations.h,v 1.20 2016/05/22 10:28:23 bcoconni Exp

Definition at line 106 of file FGAccelerations.h.

Member Enumeration Documentation

◆ eGravType

enum eGravType

These define the indices use to select the gravitation models.

Enumerator
gtStandard	Evaluate gravity using Newton's classical formula assuming the Earth is spherical.
gtWGS84	Evaluate gravity using WGS84 formulas that take the Earth oblateness into account.

Definition at line 116 of file FGAccelerations.h.

                  {
     gtStandard,
     gtWGS84
   };

Constructor & Destructor Documentation

◆ FGAccelerations()

FGAccelerations ( FGFDMExec * Executive )

Constructor.

Parameters

Executive a pointer to the parent executive object

Definition at line 70 of file FGAccelerations.cpp.

   : FGModel(fdmex)
 {
   Debug(0);
   Name = "FGAccelerations";
   gravType = gtWGS84;
   gravTorque = false;
 
   vPQRidot.InitMatrix();
   vUVWidot.InitMatrix();
   vUVWdot.InitMatrix();
   vGravAccel.InitMatrix();
   vBodyAccel.InitMatrix();
 
   bind();
   Debug(0);
 }

Member Function Documentation

◆ GetBodyAccel() [1/2]

const FGColumnVector3& GetBodyAccel ( void ) const

inline

Retrieves the acceleration resulting from the applied forces.

Retrieves the ratio of the sum of all forces applied on the craft to its mass. This does include the friction forces but not the gravity. The vector returned is represented by an FGColumnVector3 reference. The vector for the acceleration in Body frame is organized (Ax, Ay, Az). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vBodyAccel(1) is Ax. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eX=1, eY=2, eZ=3. units ft/sec^2

Returns: The acceleration resulting from the applied forces.

Definition at line 222 of file FGAccelerations.h.

222 { return vBodyAccel; }

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◆ GetBodyAccel() [2/2]

double GetBodyAccel ( int idx ) const

inline

Retrieves a component of the acceleration resulting from the applied forces.

Retrieves a component of the ratio between the sum of all forces applied on the craft to its mass. The value returned is extracted from the vBodyAccel vector (an FGColumnVector3). The vector for the acceleration in Body frame is organized (Ax, Ay, Az). The vector is 1-based. In other words, GetBodyAccel(1) returns Ax. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eX=1, eY=2, eZ=3. units ft/sec^2

Parameters

idx	the index of the acceleration component desired (1-based).

Returns: The component of the acceleration resulting from the applied forces.

Definition at line 240 of file FGAccelerations.h.

240 { return vBodyAccel(idx); }

◆ GetForces()

double GetForces ( int idx ) const

inline

Retrieves the total forces applied on the body.

Retrieves the total forces applied on the body. This does include the friction forces but not the gravity. The vector for the total forces in the body frame is organized (Fx, Fy , Fz). The vector is 1-based. In other words, GetForces(1) returns Fx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the forces returned by this call are, eX=1, eY=2, eZ=3. units lbs

Parameters

idx	the index of the forces component desired (1-based).

Returns: The total forces applied on the body.

Definition at line 282 of file FGAccelerations.h.

282 { return in.Force(idx) + vFrictionForces(idx); }

JSBSim::FGAccelerations::Inputs::Force

FGColumnVector3 Force

Total forces applied to the body except friction and gravity (expressed in the body frame) ...

Definition: FGAccelerations.h:357

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◆ GetGroundForces()

double GetGroundForces ( int idx ) const

inline

Retrieves the ground forces applied on the body.

Retrieves the ground forces applied on the body. This does include the ground normal reaction and friction forces. The vector for the ground forces in the body frame is organized (Fx, Fy , Fz). The vector is 1-based. In other words, GetGroundForces(1) returns Fx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the forces returned by this call are, eX=1, eY=2, eZ=3. units lbs.

Parameters

idx	the index of the forces component desired (1-based).

Returns: The ground forces applied on the body.

Definition at line 310 of file FGAccelerations.h.

310 { return in.GroundForce(idx) + vFrictionForces(idx); }

JSBSim::FGAccelerations::Inputs::GroundForce

FGColumnVector3 GroundForce

Forces generated by the ground normal reactions expressed in the body frame. Does not account for fri...

Definition: FGAccelerations.h:359

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◆ GetGroundMoments()

double GetGroundMoments ( int idx ) const

inline

Retrieves the ground moments applied on the body.

Retrieves the ground moments applied on the body. This does include the ground normal reaction and friction moments. The vector for the ground moments in the body frame is organized (Mx, My , Mz). The vector is 1-based. In other words, GetGroundMoments(1) returns Mx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the moments returned by this call are, eX=1, eY=2, eZ=3. units lbs*ft

Parameters

idx	the index of the moments component desired (1-based).

Returns: The ground moments applied on the body.

Definition at line 296 of file FGAccelerations.h.

296 { return in.GroundMoment(idx) + vFrictionMoments(idx); }

JSBSim::FGAccelerations::Inputs::GroundMoment

FGColumnVector3 GroundMoment

Moments generated by the ground normal reactions expressed in the body frame. Does not account for fr...

Definition: FGAccelerations.h:355

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◆ GetMoments()

double GetMoments ( int idx ) const

inline

Retrieves a component of the total moments applied on the body.

Retrieves a component of the total moments applied on the body. This does include the moments generated by friction forces and the gravitational torque (if the property simulation/gravitational-torque is set to true). The vector for the total moments in the body frame is organized (Mx, My , Mz). The vector is 1-based. In other words, GetMoments(1) returns Mx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the moments returned by this call are, eX=1, eY=2, eZ=3. units lbs*ft

Parameters

idx	the index of the moments component desired (1-based).

Returns: The total moments applied on the body.

Definition at line 268 of file FGAccelerations.h.

268 { return in.Moment(idx) + vFrictionMoments(idx); }

JSBSim::FGAccelerations::Inputs::Moment

FGColumnVector3 Moment

Total moments applied to the body except friction and gravity (expressed in the body frame) ...

Definition: FGAccelerations.h:353

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◆ GetPQRdot() [1/2]

const FGColumnVector3& GetPQRdot ( void ) const

inline

Retrieves the body axis angular acceleration vector.

Retrieves the body axis angular acceleration vector in rad/sec^2. The angular acceleration vector is determined from the applied moments and accounts for a rotating frame. The vector returned is represented by an FGColumnVector3 reference. The vector for the angular acceleration in Body frame is organized (Pdot, Qdot, Rdot). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vPQRdot(1) is Pdot. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eP=1, eQ=2, eR=3. units rad/sec^2

Returns: The angular acceleration vector.

Definition at line 180 of file FGAccelerations.h.

180 {return vPQRdot;}

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◆ GetPQRdot() [2/2]

double GetPQRdot ( int axis ) const

inline

Retrieves a body frame angular acceleration component.

Retrieves a body frame angular acceleration component. The angular acceleration returned is extracted from the vPQRdot vector (an FGColumnVector3). The vector for the angular acceleration in Body frame is organized (Pdot, Qdot, Rdot). The vector is 1-based. In other words, GetPQRdot(1) returns Pdot (roll acceleration). Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the angular acceleration returned by this call are, eP=1, eQ=2, eR=3. units rad/sec^2

Parameters

axis	the index of the angular acceleration component desired (1-based).

Returns: The body frame angular acceleration component.

Definition at line 254 of file FGAccelerations.h.

254 {return vPQRdot(axis);}

◆ GetPQRidot()

const FGColumnVector3& GetPQRidot ( void ) const

inline

Retrieves the axis angular acceleration vector in the ECI frame.

Retrieves the body axis angular acceleration vector measured in the ECI frame and expressed in the body frame. The angular acceleration vector is determined from the applied moments. The vector returned is represented by an FGColumnVector3 reference. The vector for the angular acceleration in Body frame is organized (Pidot, Qidot, Ridot). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vPQRidot(1) is Pidot. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eP=1, eQ=2, eR=3. units rad/sec^2

Returns: The angular acceleration vector.

Definition at line 195 of file FGAccelerations.h.

195 {return vPQRidot;}

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◆ GetUVWdot() [1/2]

const FGColumnVector3& GetUVWdot ( void ) const

inline

Retrieves the body axis acceleration.

Retrieves the computed body axis accelerations based on the applied forces and accounting for a rotating body frame. The vector returned is represented by an FGColumnVector3 reference. The vector for the acceleration in Body frame is organized (Ax, Ay, Az). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vUVWdot(1) is Ax. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eX=1, eY=2, eZ=3. units ft/sec^2

Returns: Body axis translational acceleration in ft/sec^2.

Definition at line 149 of file FGAccelerations.h.

149 { return vUVWdot; }

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◆ GetUVWdot() [2/2]

double GetUVWdot ( int idx ) const

inline

Retrieves a body frame acceleration component.

Retrieves a body frame acceleration component. The acceleration returned is extracted from the vUVWdot vector (an FGColumnVector3). The vector for the acceleration in Body frame is organized (Ax, Ay, Az). The vector is 1-based. In other words, GetUVWdot(1) returns Ax. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the acceleration returned by this call are, eX=1, eY=2, eZ=3. units ft/sec^2

Parameters

idx	the index of the acceleration component desired (1-based).

Returns: The body frame acceleration component.

Definition at line 208 of file FGAccelerations.h.

208 { return vUVWdot(idx); }

◆ GetUVWidot()

const FGColumnVector3& GetUVWidot ( void ) const

inline

Retrieves the body axis acceleration in the ECI frame.

Retrieves the computed body axis accelerations based on the applied forces. The ECI frame being an inertial frame this vector does not contain the Coriolis and centripetal accelerations. The vector is expressed in the Body frame. The vector returned is represented by an FGColumnVector3 reference. The vector for the acceleration in Body frame is organized (Aix, Aiy, Aiz). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vUVWidot(1) is Aix. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eX=1, eY=2, eZ=3. units ft/sec^2

Returns: Body axis translational acceleration in ft/sec^2.

Definition at line 165 of file FGAccelerations.h.

165 { return vUVWidot; }

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◆ GetWeight()

double GetWeight ( int idx ) const

inline

Retrieves the weight applied on the body.

Retrieves the weight applied on the body i.e. the force that results from the gravity applied to the body mass. The vector for the weight forces in the body frame is organized (Fx, Fy , Fz). The vector is 1-based. In other words, GetWeight(1) returns Fx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the forces returned by this call are, eX=1, eY=2, eZ=3. units lbs.

Parameters

idx	the index of the forces component desired (1-based).

Returns: The ground forces applied on the body.

Definition at line 324 of file FGAccelerations.h.

324 { return in.Mass * (in.Ti2b * vGravAccel)(idx); }

JSBSim::FGAccelerations::Inputs::Ti2b

FGMatrix33 Ti2b

Transformation matrix from the ECI to the Body frame.

Definition: FGAccelerations.h:345

JSBSim::FGAccelerations::Inputs::Mass

double Mass

Body mass.

Definition: FGAccelerations.h:379

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◆ InitializeDerivatives()

void InitializeDerivatives ( void )

Initializes the FGAccelerations class prior to a new execution.

Initializes the class prior to a new execution when the input data stored in the Inputs structure have been set to their initial values.

Definition at line 345 of file FGAccelerations.cpp.

 {
   // Make an initial run and set past values
   CalculatePQRdot();           // Angular rate derivative
   CalculateUVWdot();           // Translational rate derivative
   ResolveFrictionForces(0.);   // Update rate derivatives with friction forces
 }

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◆ InitModel()

bool InitModel ( void )

virtual

Initializes the FGAccelerations class after instantiation and prior to first execution.

The base class FGModel::InitModel is called first, initializing pointers to the other FGModel objects (and others).

Reimplemented from FGModel.

Definition at line 97 of file FGAccelerations.cpp.

 {
   if (!FGModel::InitModel()) return false;
 
   vPQRidot.InitMatrix();
   vUVWidot.InitMatrix();
   vUVWdot.InitMatrix();
   vGravAccel.InitMatrix();
   vBodyAccel.InitMatrix();
 
   return true;
 }

◆ Run()

bool Run ( bool Holding )

virtual

Runs the state propagation model; called by the Executive 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 115 of file FGAccelerations.cpp.

 {
   if (FGModel::Run(Holding)) return true;  // Fast return if we have nothing to do ...
   if (Holding) return false;
 
   CalculatePQRdot();   // Angular rate derivative
   CalculateUVWdot();   // Translational rate derivative
 
   if (!FDMExec->GetHoldDown())
     ResolveFrictionForces(in.DeltaT * rate);  // Update rate derivatives with friction forces
 
   Debug(2);
   return false;
 }

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◆ SetHoldDown()

void SetHoldDown ( bool hd )

Sets the property forces/hold-down.

This allows to do hard 'hold-down' such as for rockets on a launch pad with engines ignited.

Parameters

hd	enables the 'hold-down' function if non-zero

Definition at line 228 of file FGAccelerations.cpp.

 {
   if (hd) {
     vUVWidot = in.vOmegaPlanet * (in.vOmegaPlanet * in.vInertialPosition);
     vUVWdot.InitMatrix();
     vPQRidot = in.vPQRi * (in.Ti2b * in.vOmegaPlanet);
     vPQRdot.InitMatrix();
   }
 }

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

Classes

Public Types

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ eGravType

Constructor & Destructor Documentation

◆ FGAccelerations()

Member Function Documentation

◆ GetBodyAccel() [1/2]

◆ GetBodyAccel() [2/2]

◆ GetForces()

◆ GetGroundForces()

◆ GetGroundMoments()

◆ GetMoments()

◆ GetPQRdot() [1/2]

◆ GetPQRdot() [2/2]

◆ GetPQRidot()

◆ GetUVWdot() [1/2]

◆ GetUVWdot() [2/2]

◆ GetUVWidot()

◆ GetWeight()

◆ InitializeDerivatives()

◆ InitModel()

◆ Run()

◆ SetHoldDown()