FlightGear: JSBSim::FGLGear Class Reference

Landing gear model. More...

#include <FGLGear.h>

Inherits JSBSim::FGSurface, and JSBSim::FGForce.

Classes
struct	Inputs

Public Types
enum	BrakeGroup { bgNone =0 , bgLeft , bgRight , bgCenter , bgNose , bgTail , bgNumBrakeGroups }
	Brake grouping enumerators. More...

enum	SteerType { stSteer , stFixed , stCaster }
	Steering group membership enumerators. More...

enum	ContactType { ctBOGEY , ctSTRUCTURE }
	Contact point type. More...

enum	ReportType { erNone =0 , erTakeoff , erLand }
	Report type enumerators. More...

enum	DampType { dtLinear =0 , dtSquare }
	Damping types. More...

enum	FrictionType { ftRoll =0 , ftSide , ftDynamic }
	Friction types. More...

Public Types inherited from JSBSim::FGForce
enum	TransformType { tNone , tWindBody , tLocalBody , tCustom }

Public Types inherited from JSBSim::FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...

enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...

enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...

enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...

enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...

enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...

enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...

enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...

enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...

enum	{ inNone = 0 , inDegrees , inRadians , inMeters , inFeet }
	Conversion specifiers. More...

Public Member Functions
	FGLGear (Element el, FGFDMExec Executive, int number, const struct Inputs &input)
	Constructor.

	~FGLGear ()
	Destructor.

const FGColumnVector3 &	GetBodyForces (FGSurface *surface=NULL)
	The Force vector for this gear.

FGColumnVector3	GetBodyLocation (void) const
	Gets the location of the gear in Body axes.

double	GetBodyLocation (int idx) const

const FGColumnVector3 &	GetLocalGear (void) const

double	GetLocalGear (int idx) const

const std::string &	GetName (void) const
	Gets the name of the gear.

bool	GetWOW (void) const
	Gets the Weight On Wheels flag value.

double	GetCompLen (void) const
	Gets the current compressed length of the gear in feet.

double	GetCompVel (void) const
	Gets the current gear compression velocity in ft/sec.

double	GetCompForce (void) const
	Gets the gear compression force in pounds.

void	SetWOW (bool wow)
	Sets the weight-on-wheels flag.

void	SetReport (bool flag)
	Set the console touchdown reporting feature.

bool	GetReport (void) const
	Get the console touchdown reporting feature.

double	GetSteerNorm (void) const

void	SetSteerCmd (double cmd)

double	GetstaticFCoeff (void) const

int	GetBrakeGroup (void) const

int	GetSteerType (void) const

bool	GetSteerable (void) const

bool	GetRetractable (void) const

bool	GetGearUnitUp (void) const

bool	GetGearUnitDown (void) const

double	GetWheelRollForce (void)

double	GetWheelSideForce (void)

double	GetBodyXForce (void)

double	GetBodyYForce (void)

double	GetBodyZForce (void)

double	GetWheelRollVel (void) const

double	GetWheelSideVel (void) const

double	GetWheelSlipAngle (void) const

double	GetWheelVel (int axis) const

bool	IsBogey (void) const

double	GetGearUnitPos (void) const

double	GetSteerAngleDeg (void) const

void	SetSteerAngleDeg (double angle)

void	ResetToIC (void)

void	bind (void)

Public Member Functions inherited from JSBSim::FGForce
	FGForce (FGFDMExec *FDMExec)
	Constructor.

	FGForce (const FGForce &force)

virtual	~FGForce ()
	Destructor.

virtual const FGColumnVector3 &	GetBodyForces (void)

double	GetBodyXForce (void) const

double	GetBodyYForce (void) const

double	GetBodyZForce (void) const

const FGColumnVector3 &	GetMoments (void) const

void	SetLocation (double x, double y, double z)

void	SetActingLocation (double x, double y, double z)
	Acting point of application.

void	SetLocationX (double x)

void	SetLocationY (double y)

void	SetLocationZ (double z)

double	SetActingLocationX (double x)

double	SetActingLocationY (double y)

double	SetActingLocationZ (double z)

void	SetLocation (const FGColumnVector3 &vv)

void	SetActingLocation (const FGColumnVector3 &vv)

double	GetLocationX (void) const

double	GetLocationY (void) const

double	GetLocationZ (void) const

double	GetActingLocationX (void) const

double	GetActingLocationY (void) const

double	GetActingLocationZ (void) const

const FGColumnVector3 &	GetLocation (void) const

const FGColumnVector3 &	GetActingLocation (void) const

void	SetAnglesToBody (double broll, double bpitch, double byaw)

void	SetAnglesToBody (const FGColumnVector3 &vv)

void	UpdateCustomTransformMatrix (void)

void	SetPitch (double pitch)

void	SetYaw (double yaw)

double	GetPitch (void) const

double	GetYaw (void) const

const FGColumnVector3 &	GetAnglesToBody (void) const

double	GetAnglesToBody (int axis) const

void	SetTransformType (TransformType ii)

TransformType	GetTransformType (void) const

const FGMatrix33 &	Transform (void) const

Public Member Functions inherited from JSBSim::FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.

virtual	~FGJSBBase ()
	Destructor for FGJSBBase.

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

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

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

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

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

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

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

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

void	disableHighLighting (void)
	Disables highlighting in the console output.

Public Attributes
const struct Inputs &	in

Additional Inherited Members
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.

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

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

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

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

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

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

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

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

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

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

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

static double	MachFromImpactPressure (double qc, double p)
	Compute the Mach number from the differential pressure (qc) and the static pressure.

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

static double	MachFromVcalibrated (double vcas, double p)
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.

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 double	GaussianRandomNumber (void)

Static Public Attributes inherited from JSBSim::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 Types inherited from JSBSim::FGSurface
enum	ContactType { ctBOGEY , ctSTRUCTURE , ctGROUND }

Protected Types inherited from JSBSim::FGForce
enum	TransformType { tNone , tWindBody , tLocalBody , tCustom }

Protected Types inherited from JSBSim::FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...

enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...

enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...

enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...

enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...

enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...

enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...

enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...

enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...

enum	{ inNone = 0 , inDegrees , inRadians , inMeters , inFeet }
	Conversion specifiers. More...

Protected Member Functions inherited from JSBSim::FGSurface
	FGSurface (FGFDMExec *fdmex, int number=-1)
	Constructor.

	~FGSurface ()
	Destructor.

void	bind (void)

void	resetValues (void)
	Reset all surface values to a default.

void	SetStaticFFactor (double friction)
	Sets the static friction factor of the surface area.

void	SetRollingFFactor (double friction)
	Sets the rolling friction factor of the surface area.

void	SetMaximumForce (double force)
	Sets the maximum force for the surface area.

void	SetBumpiness (double bump)
	Sets the normalized bumpiness factor associated with the surface.

void	SetSolid (bool solid)
	Sets the surface is a solid flag value.

void	SetPosition (const double pt[3])
	Set the currect position for bumpiness calulcation.

void	SetBumpHeight (float height)
	Sets the height of the bump at the provided offset.

double	GetStaticFFactor (void)
	Gets the static friction factor of the surface area.

double	GetRollingFFactor (void)
	Gets the rolling friction factor of the surface area.

double	GetMaximumForce (void)
	Gets the maximum force of the surface area.

double	GetBumpiness (void)
	Gets the normalized bumpiness factor associated with the surface.

bool	GetSolid (void)
	Gets the surface is a solid flag value.

float	GetBumpHeight ()
	Returns the height of the bump at the provided offset.

std::string	GetSurfaceStrings (std::string delimeter) const

std::string	GetSurfaceValues (std::string delimeter) const

Protected Member Functions inherited from JSBSim::FGForce
	FGForce (FGFDMExec *FDMExec)
	Constructor.

	FGForce (const FGForce &force)

virtual	~FGForce ()
	Destructor.

virtual const FGColumnVector3 &	GetBodyForces (void)

double	GetBodyXForce (void) const

double	GetBodyYForce (void) const

double	GetBodyZForce (void) const

const FGColumnVector3 &	GetMoments (void) const

void	SetLocation (double x, double y, double z)

void	SetActingLocation (double x, double y, double z)
	Acting point of application.

void	SetLocationX (double x)

void	SetLocationY (double y)

void	SetLocationZ (double z)

double	SetActingLocationX (double x)

double	SetActingLocationY (double y)

double	SetActingLocationZ (double z)

void	SetLocation (const FGColumnVector3 &vv)

void	SetActingLocation (const FGColumnVector3 &vv)

double	GetLocationX (void) const

double	GetLocationY (void) const

double	GetLocationZ (void) const

double	GetActingLocationX (void) const

double	GetActingLocationY (void) const

double	GetActingLocationZ (void) const

const FGColumnVector3 &	GetLocation (void) const

const FGColumnVector3 &	GetActingLocation (void) const

void	SetAnglesToBody (double broll, double bpitch, double byaw)

void	SetAnglesToBody (const FGColumnVector3 &vv)

void	UpdateCustomTransformMatrix (void)

void	SetPitch (double pitch)

void	SetYaw (double yaw)

double	GetPitch (void) const

double	GetYaw (void) const

const FGColumnVector3 &	GetAnglesToBody (void) const

double	GetAnglesToBody (int axis) const

void	SetTransformType (TransformType ii)

TransformType	GetTransformType (void) const

const FGMatrix33 &	Transform (void) const

Protected Member Functions inherited from JSBSim::FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.

virtual	~FGJSBBase ()
	Destructor for FGJSBBase.

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

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

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

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

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

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

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

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

void	disableHighLighting (void)
	Disables highlighting in the console output.

static std::string	CreateIndexedPropertyName (const std::string &Property, int index)

static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.

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

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

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

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

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

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

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

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

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

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

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

static double	MachFromImpactPressure (double qc, double p)
	Compute the Mach number from the differential pressure (qc) and the static pressure.

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

static double	MachFromVcalibrated (double vcas, double p)
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.

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 double	GaussianRandomNumber (void)

Protected Attributes inherited from JSBSim::FGSurface
ContactType	eSurfaceType = ctBOGEY

double	staticFFactor = 1.0

double	rollingFFactor = 1.0

double	maximumForce = DBL_MAX

double	bumpiness = 0.0

bool	isSolid = true

double	staticFCoeff = 1.0

double	dynamicFCoeff = 1.0

Protected Attributes inherited from JSBSim::FGForce
FGFDMExec *	fdmex

FGMassBalance *	MassBalance

FGColumnVector3	vFn

FGColumnVector3	vMn

FGColumnVector3	vOrient

TransformType	ttype

FGColumnVector3	vXYZn

FGColumnVector3	vActingXYZn

FGMatrix33	mT

static Message	localMsg

static std::queue< Message >	Messages

static unsigned int	messageId = 0

static constexpr double	radtodeg = 180. / 3.14159265358979323846

static constexpr double	degtorad = 3.14159265358979323846 / 180.

static constexpr double	hptoftlbssec = 550.0

static constexpr double	psftoinhg = 0.014138

static constexpr double	psftopa = 47.88

static constexpr double	ktstofps = 1.68781

static constexpr double	fpstokts = 1.0 / ktstofps

static constexpr double	inchtoft = 1.0/12.0

static constexpr double	fttom = 0.3048

static constexpr double	m3toft3 = 1.0/(fttomfttomfttom)

static constexpr double	in3tom3 = inchtoftinchtoftinchtoft/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.

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__

static int	gaussian_random_number_phase = 0

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

Detailed Description

Landing gear model.

Calculates forces and moments due to landing gear reactions. This is done in several steps, and is dependent on what kind of gear is being modeled. Here are the parameters that can be specified in the config file for modeling landing gear:

Physical Characteristics

X, Y, Z location, in inches in structural coordinate frame
Spring constant, in lbs/ft
Damping coefficient, in lbs/ft/sec
Dynamic Friction Coefficient
Static Friction Coefficient

Operational Properties

Name
Brake Group Membership {one of LEFT | CENTER | RIGHT | NOSE | TAIL | NONE}
Max Steer Angle, in degrees

Algorithm and Approach to Modeling

Find the location of the uncompressed landing gear relative to the CG of the aircraft. Remember, the structural coordinate frame that the aircraft is defined in is: X positive towards the tail, Y positive out the right side, Z positive upwards. The locations of the various parts are given in inches in the config file.
The vector giving the location of the gear (relative to the cg) is rotated 180 degrees about the Y axis to put the coordinates in body frame (X positive forwards, Y positive out the right side, Z positive downwards, with the origin at the cg). The lengths are also now given in feet.
The new gear location is now transformed to the local coordinate frame using the body-to-local matrix. (Mb2l).
Knowing the location of the center of gravity relative to the ground (height above ground level or AGL) now enables gear deflection to be calculated. The gear compression value is the local frame gear Z location value minus the height AGL. [Currently, we make the assumption that the gear is oriented - and the deflection occurs in - the Z axis only. Additionally, the vector to the landing gear is currently not modified - which would (correctly) move the point of contact to the actual compressed-gear point of contact. Eventually, articulated gear may be modeled, but initially an effort must be made to model a generic system.] As an example, say the aircraft left main gear location (in local coordinates) is Z = 3 feet (positive) and the height AGL is 2 feet. This tells us that the gear is compressed 1 foot.
If the gear is compressed, a Weight-On-Wheels (WOW) flag is set.
With the compression length calculated, the compression velocity may now be calculated. This will be used to determine the damping force in the strut. The aircraft rotational rate is multiplied by the vector to the wheel to get a wheel velocity in body frame. That velocity vector is then transformed into the local coordinate frame.
The aircraft cg velocity in the local frame is added to the just-calculated wheel velocity (due to rotation) to get a total wheel velocity in the local frame.
The compression speed is the Z-component of the vector.
With the wheel velocity vector no longer needed, it is normalized and multiplied by a -1 to reverse it. This will be used in the friction force calculation.
Since the friction force takes place solely in the runway plane, the Z coordinate of the normalized wheel velocity vector is set to zero.
The gear deflection force (the force on the aircraft acting along the local frame Z axis) is now calculated given the spring and damper coefficients, and the gear deflection speed and stroke length. Keep in mind that gear forces always act in the negative direction (in both local and body frames), and are not capable of generating a force in the positive sense (one that would attract the aircraft to the ground). So, the gear forces are always negative - they are limited to values of zero or less. The gear force is simply the negative of the sum of the spring compression length times the spring coefficient and the gear velocity times the damping coefficient.
The lateral/directional force acting on the aircraft through the landing

gear (along the local frame X and Y axes) is calculated next. First, the friction coefficient is multiplied by the recently calculated Z-force. This is the friction force. It must be given direction in addition to magnitude. We want the components in the local frame X and Y axes. From step 9, above, the conditioned wheel velocity vector is taken and the X and Y parts are multiplied by the friction force to get the X and Y components of friction.
The wheel force in local frame is next converted to body frame.
The moment due to the gear force is calculated by multiplying r x F (radius to wheel crossed into the wheel force). Both of these operands are in body frame.

Configuration File Format for <contact> Section:

<contact type="{BOGEY | STRUCTURE}" name="{string}">
    <location unit="{IN | M}">
        <x> {number} </x>
        <y> {number} </y>
        <z> {number} </z>
    </location>
    <orientation unit="{RAD | DEG}">
        <pitch> {number} </pitch>
        <roll> {number} </roll>
        <yaw> {number} </yaw>
    </orientation>
    <static_friction> {number} </static_friction>
    <dynamic_friction> {number} </dynamic_friction>
    <rolling_friction> {number} </rolling_friction>
    <spring_coeff unit="{LBS/FT | N/M}"> {number} </spring_coeff>
    <damping_coeff type="{ | SQUARE}" unit="{LBS/FT/SEC | N/M/SEC}"> {number} </damping_coeff>
    <damping_coeff_rebound type="{ | SQUARE}" unit="{LBS/FT/SEC | N/M/SEC}"> {number} </damping_coeff_rebound>
    <max_steer unit="DEG"> {number | 0 | 360} </max_steer>
    <brake_group> {NONE | LEFT | RIGHT | CENTER | NOSE | TAIL} </brake_group>
    <retractable>{0 | 1}</retractable>
    <table name="{CORNERING_COEFF}" type="internal">
        <tableData>
            {cornering parameters}
        </tableData>
    </table>
</contact>

Author: Jon S. Berndt

See also: Richard E. McFarland, "A Standard Kinematic Model for Flight Simulation at NASA-Ames", NASA CR-2497, January 1975; Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics", Wiley & Sons, 1979 ISBN 0-471-03032-5; W. A. Ragsdale, "A Generic Landing Gear Dynamics Model for LASRS++", AIAA-2000-4303

Definition at line 190 of file FGLGear.h.

Member Enumeration Documentation

◆ BrakeGroup

enum JSBSim::FGLGear::BrakeGroup

Brake grouping enumerators.

Enumerator
bgNone
bgLeft
bgRight
bgCenter
bgNose
bgTail
bgNumBrakeGroups

Definition at line 215 of file FGLGear.h.

◆ ContactType

enum JSBSim::FGLGear::ContactType

Contact point type.

Enumerator
ctBOGEY
ctSTRUCTURE

Definition at line 219 of file FGLGear.h.

◆ DampType

enum JSBSim::FGLGear::DampType

Damping types.

Enumerator
dtLinear
dtSquare

Definition at line 223 of file FGLGear.h.

◆ FrictionType

enum JSBSim::FGLGear::FrictionType

Friction types.

Enumerator
ftRoll
ftSide
ftDynamic

Definition at line 225 of file FGLGear.h.

◆ ReportType

enum JSBSim::FGLGear::ReportType

Report type enumerators.

Enumerator
erNone
erTakeoff
erLand

Definition at line 221 of file FGLGear.h.

◆ SteerType

enum JSBSim::FGLGear::SteerType

Steering group membership enumerators.

Enumerator
stSteer
stFixed
stCaster

Definition at line 217 of file FGLGear.h.

Constructor & Destructor Documentation

◆ FGLGear()

JSBSim::FGLGear::FGLGear	(	Element *	el,
		FGFDMExec *	Executive,
		int	number,
		const struct Inputs &	input )

Constructor.

Parameters

el	a pointer to the XML element that contains the CONTACT info.
Executive	a pointer to the parent executive object
number	integer identifier for this instance of FGLGear

Definition at line 71 of file FGLGear.cpp.

◆ ~FGLGear()

JSBSim::FGLGear::~FGLGear ( )

Destructor.

Definition at line 238 of file FGLGear.cpp.

Member Function Documentation

◆ bind()

void JSBSim::FGLGear::bind ( void )

Definition at line 770 of file FGLGear.cpp.

◆ GetBodyForces()

const FGColumnVector3 & JSBSim::FGLGear::GetBodyForces ( FGSurface * surface = NULL )

The Force vector for this gear.

Parameters

surface another surface to interact with, set to NULL for none.

Definition at line 279 of file FGLGear.cpp.

◆ GetBodyLocation() [1/2]

double JSBSim::FGLGear::GetBodyLocation ( int idx ) const

inline

Definition at line 244 of file FGLGear.h.

◆ GetBodyLocation() [2/2]

FGColumnVector3 JSBSim::FGLGear::GetBodyLocation ( void ) const

inline

Gets the location of the gear in Body axes.

Definition at line 241 of file FGLGear.h.

◆ GetBodyXForce()

double JSBSim::FGLGear::GetBodyXForce ( void )

inline

Definition at line 294 of file FGLGear.h.

◆ GetBodyYForce()

double JSBSim::FGLGear::GetBodyYForce ( void )

inline

Definition at line 298 of file FGLGear.h.

◆ GetBodyZForce()

double JSBSim::FGLGear::GetBodyZForce ( void )

inline

Definition at line 302 of file FGLGear.h.

◆ GetBrakeGroup()

int JSBSim::FGLGear::GetBrakeGroup ( void ) const

inline

Definition at line 278 of file FGLGear.h.

◆ GetCompForce()

double JSBSim::FGLGear::GetCompForce ( void ) const

inline

Gets the gear compression force in pounds.

Definition at line 261 of file FGLGear.h.

◆ GetCompLen()

double JSBSim::FGLGear::GetCompLen ( void ) const

inline

Gets the current compressed length of the gear in feet.

Definition at line 257 of file FGLGear.h.

◆ GetCompVel()

double JSBSim::FGLGear::GetCompVel ( void ) const

inline

Gets the current gear compression velocity in ft/sec.

Definition at line 259 of file FGLGear.h.

◆ GetGearUnitDown()

bool JSBSim::FGLGear::GetGearUnitDown ( void ) const

inline

Definition at line 284 of file FGLGear.h.

◆ GetGearUnitPos()

double JSBSim::FGLGear::GetGearUnitPos ( void ) const

Definition at line 661 of file FGLGear.cpp.

◆ GetGearUnitUp()

bool JSBSim::FGLGear::GetGearUnitUp ( void ) const

inline

Definition at line 283 of file FGLGear.h.

◆ GetLocalGear() [1/2]

double JSBSim::FGLGear::GetLocalGear ( int idx ) const

inline

Definition at line 250 of file FGLGear.h.

◆ GetLocalGear() [2/2]

const FGColumnVector3 & JSBSim::FGLGear::GetLocalGear ( void ) const

inline

Definition at line 249 of file FGLGear.h.

◆ GetName()

const std::string & JSBSim::FGLGear::GetName ( void ) const

inline

Gets the name of the gear.

Definition at line 253 of file FGLGear.h.

◆ GetReport()

bool JSBSim::FGLGear::GetReport ( void ) const

inline

Get the console touchdown reporting feature.

Returns: true if reporting is turned on

Definition at line 271 of file FGLGear.h.

◆ GetRetractable()

bool JSBSim::FGLGear::GetRetractable ( void ) const

inline

Definition at line 282 of file FGLGear.h.

◆ GetstaticFCoeff()

double JSBSim::FGLGear::GetstaticFCoeff ( void ) const

inline

Definition at line 276 of file FGLGear.h.

◆ GetSteerable()

bool JSBSim::FGLGear::GetSteerable ( void ) const

inline

Definition at line 281 of file FGLGear.h.

◆ GetSteerAngleDeg()

double JSBSim::FGLGear::GetSteerAngleDeg ( void ) const

inline

Definition at line 314 of file FGLGear.h.

◆ GetSteerNorm()

double JSBSim::FGLGear::GetSteerNorm ( void ) const

inline

Definition at line 272 of file FGLGear.h.

◆ GetSteerType()

int JSBSim::FGLGear::GetSteerType ( void ) const

inline

Definition at line 279 of file FGLGear.h.

◆ GetWheelRollForce()

double JSBSim::FGLGear::GetWheelRollForce ( void )

inline

Definition at line 286 of file FGLGear.h.

◆ GetWheelRollVel()

double JSBSim::FGLGear::GetWheelRollVel ( void ) const

inline

Definition at line 306 of file FGLGear.h.

◆ GetWheelSideForce()

double JSBSim::FGLGear::GetWheelSideForce ( void )

inline

Definition at line 290 of file FGLGear.h.

◆ GetWheelSideVel()

double JSBSim::FGLGear::GetWheelSideVel ( void ) const

inline

Definition at line 308 of file FGLGear.h.

◆ GetWheelSlipAngle()

double JSBSim::FGLGear::GetWheelSlipAngle ( void ) const

inline

Definition at line 310 of file FGLGear.h.

◆ GetWheelVel()

double JSBSim::FGLGear::GetWheelVel ( int axis ) const

inline

Definition at line 311 of file FGLGear.h.

◆ GetWOW()

bool JSBSim::FGLGear::GetWOW ( void ) const

inline

Gets the Weight On Wheels flag value.

Definition at line 255 of file FGLGear.h.

◆ IsBogey()

bool JSBSim::FGLGear::IsBogey ( void ) const

inline

Definition at line 312 of file FGLGear.h.

◆ ResetToIC()

void JSBSim::FGLGear::ResetToIC ( void )

Definition at line 247 of file FGLGear.cpp.

◆ SetReport()

void JSBSim::FGLGear::SetReport ( bool flag )

inline

Set the console touchdown reporting feature.

Parameters

flag	true turns on touchdown reporting, false turns it off

Definition at line 268 of file FGLGear.h.

◆ SetSteerAngleDeg()

void JSBSim::FGLGear::SetSteerAngleDeg ( double angle )

inline

Definition at line 315 of file FGLGear.h.

◆ SetSteerCmd()

void JSBSim::FGLGear::SetSteerCmd ( double cmd )

inline

Definition at line 275 of file FGLGear.h.

◆ SetWOW()

void JSBSim::FGLGear::SetWOW ( bool wow )

inline

Sets the weight-on-wheels flag.

Definition at line 264 of file FGLGear.h.

Member Data Documentation

◆ in

const struct Inputs& JSBSim::FGLGear::in

Definition at line 320 of file FGLGear.h.

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

Classes

Public Types

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Physical Characteristics

Operational Properties

Algorithm and Approach to Modeling

Configuration File Format for <contact> Section:

Member Enumeration Documentation

◆ BrakeGroup

◆ ContactType

◆ DampType

◆ FrictionType

◆ ReportType

◆ SteerType

Constructor & Destructor Documentation

◆ FGLGear()

◆ ~FGLGear()

Member Function Documentation

◆ bind()

◆ GetBodyForces()

◆ GetBodyLocation() [1/2]

◆ GetBodyLocation() [2/2]

◆ GetBodyXForce()

◆ GetBodyYForce()

◆ GetBodyZForce()

◆ GetBrakeGroup()

◆ GetCompForce()

◆ GetCompLen()

◆ GetCompVel()

◆ GetGearUnitDown()

◆ GetGearUnitPos()

◆ GetGearUnitUp()

◆ GetLocalGear() [1/2]

◆ GetLocalGear() [2/2]

◆ GetName()

◆ GetReport()

◆ GetRetractable()

◆ GetstaticFCoeff()

◆ GetSteerable()

◆ GetSteerAngleDeg()

◆ GetSteerNorm()

◆ GetSteerType()

◆ GetWheelRollForce()

◆ GetWheelRollVel()

◆ GetWheelSideForce()

◆ GetWheelSideVel()

◆ GetWheelSlipAngle()

◆ GetWheelVel()

◆ GetWOW()

◆ IsBogey()

◆ ResetToIC()

◆ SetReport()

◆ SetSteerAngleDeg()

◆ SetSteerCmd()

◆ SetWOW()

Member Data Documentation

◆ in