dart::dynamics::Inertia Class Reference

#include <Inertia.hpp>

Public Types
enum	Param {   MASS = 0 , COM_X , COM_Y , COM_Z ,   I_XX , I_YY , I_ZZ , I_XY ,   I_XZ , I_YZ }
	Enumeration for minimal inertia parameters. More...

Public Member Functions
	Inertia (double _mass=1, const Eigen::Vector3d &_com=Eigen::Vector3d::Zero(), const Eigen::Matrix3d &_momentOfInertia=Eigen::Matrix3d::Identity())
	Inertia (const Eigen::Matrix6d &_spatialInertiaTensor)
	Inertia (double _mass, double _comX, double _comY, double _comZ, double _Ixx, double _Iyy, double _Izz, double _Ixy, double _Ixz, double _Iyz)
void	setParameter (Param _param, double _value)
	Set an inertial parameter.
double	getParameter (Param _param) const
	Get an inertial parameter.
void	setMass (double _mass)
	Set the mass.
double	getMass () const
	Get the mass.
void	setLocalCOM (const Eigen::Vector3d &_com)
	Set the center of mass with respect to the Body-fixed frame.
const Eigen::Vector3d &	getLocalCOM () const
	Get the center of mass with respect to the Body-fixed frame.
void	setMoment (const Eigen::Matrix3d &_moment)
	Set the moment of inertia (about the center of mass).
void	setMoment (double _Ixx, double _Iyy, double _Izz, double _Ixy, double _Ixz, double _Iyz)
	Set the moment of inertia (about the center of mass)
Eigen::Matrix3d	getMoment () const
	Get the moment of inertia.
void	setSpatialTensor (const Eigen::Matrix6d &_spatial)
	Set the spatial tensor.
const Eigen::Matrix6d &	getSpatialTensor () const
	Get the spatial inertia tensor.
bool	verify (bool _printWarnings=true, double _tolerance=1e-8) const
	Returns true iff this Inertia object is physically valid.
bool	operator== (const Inertia &other) const
	Check for equality.

Static Public Member Functions
static bool	verifyMoment (const Eigen::Matrix3d &_moment, bool _printWarnings=true, double _tolerance=1e-8)
	Returns true iff _moment is a physically valid moment of inertia.
static bool	verifySpatialTensor (const Eigen::Matrix6d &_spatial, bool _printWarnings=true, double _tolerance=1e-8)
	Returns true iff _spatial is a physically valid spatial inertia tensor.

Protected Member Functions
void	computeSpatialTensor ()
	Compute the spatial tensor based on the inertial parameters.
void	computeParameters ()
	Compute the inertial parameters from the spatial tensor.

Protected Attributes
double	mMass
	Overall mass.
Eigen::Vector3d	mCenterOfMass
	Center of mass in the Body frame.
std::array< double, 6 >	mMoment
	The six parameters of the moment of inertia located at the center of mass.
Eigen::Matrix6d	mSpatialTensor
	Cache for generalized spatial inertia of the Body.

Member Enumeration Documentation

Param

enum dart::dynamics::Inertia::Param

Enumeration for minimal inertia parameters.

Enumerator
MASS
COM_X
COM_Y
COM_Z
I_XX
I_YY
I_ZZ
I_XY
I_XZ
I_YZ

Constructor & Destructor Documentation

Inertia() [1/3]

dart::dynamics::Inertia::Inertia	(	double	_mass = 1,
		const Eigen::Vector3d &	_com = Eigen::Vector3d::Zero(),
		const Eigen::Matrix3d &	_momentOfInertia = Eigen::Matrix3d::Identity()
	)

Inertia() [2/3]

dart::dynamics::Inertia::Inertia

(

const Eigen::Matrix6d &

_spatialInertiaTensor

)

Inertia() [3/3]

dart::dynamics::Inertia::Inertia	(	double	_mass,
		double	_comX,
		double	_comY,
		double	_comZ,
		double	_Ixx,
		double	_Iyy,
		double	_Izz,
		double	_Ixy,
		double	_Ixz,
		double	_Iyz
	)

Member Function Documentation

computeParameters()

void dart::dynamics::Inertia::computeParameters ( )

protected

Compute the inertial parameters from the spatial tensor.

computeSpatialTensor()

void dart::dynamics::Inertia::computeSpatialTensor ( )

protected

Compute the spatial tensor based on the inertial parameters.

getLocalCOM()

const Eigen::Vector3d & dart::dynamics::Inertia::getLocalCOM

(

)

const

Get the center of mass with respect to the Body-fixed frame.

getMass()

double dart::dynamics::Inertia::getMass

(

)

const

Get the mass.

getMoment()

Eigen::Matrix3d dart::dynamics::Inertia::getMoment

(

)

const

Get the moment of inertia.

getParameter()

double dart::dynamics::Inertia::getParameter

(

Param

_param

)

const

Get an inertial parameter.

getSpatialTensor()

const Eigen::Matrix6d & dart::dynamics::Inertia::getSpatialTensor

(

)

const

Get the spatial inertia tensor.

operator==()

bool dart::dynamics::Inertia::operator==

(

const Inertia &

other

)

const

Check for equality.

setLocalCOM()

void dart::dynamics::Inertia::setLocalCOM

(

const Eigen::Vector3d &

_com

)

Set the center of mass with respect to the Body-fixed frame.

setMass()

void dart::dynamics::Inertia::setMass

(

double

_mass

)

Set the mass.

setMoment() [1/2]

void dart::dynamics::Inertia::setMoment

(

const Eigen::Matrix3d &

_moment

)

Set the moment of inertia (about the center of mass).

Note that only the top-right corner of the matrix will be used, because a well-formed inertia matrix is always symmetric.

setMoment() [2/2]

void dart::dynamics::Inertia::setMoment	(	double	_Ixx,
		double	_Iyy,
		double	_Izz,
		double	_Ixy,
		double	_Ixz,
		double	_Iyz
	)

Set the moment of inertia (about the center of mass)

setParameter()

void dart::dynamics::Inertia::setParameter	(	Param	_param,
		double	_value
	)

Set an inertial parameter.

setSpatialTensor()

void dart::dynamics::Inertia::setSpatialTensor

(

const Eigen::Matrix6d &

_spatial

)

Set the spatial tensor.

verify()

bool dart::dynamics::Inertia::verify	(	bool	_printWarnings = true,
		double	_tolerance = 1e-8
	)		const

Returns true iff this Inertia object is physically valid.

verifyMoment()

bool dart::dynamics::Inertia::verifyMoment ( const Eigen::Matrix3d &  _moment, bool  _printWarnings = true, double  _tolerance = 1e-8  )

static

Returns true iff _moment is a physically valid moment of inertia.

verifySpatialTensor()

bool dart::dynamics::Inertia::verifySpatialTensor ( const Eigen::Matrix6d &  _spatial, bool  _printWarnings = true, double  _tolerance = 1e-8  )

static

Returns true iff _spatial is a physically valid spatial inertia tensor.

Member Data Documentation

mCenterOfMass

Eigen::Vector3d dart::dynamics::Inertia::mCenterOfMass

protected

Center of mass in the Body frame.

mMass

double dart::dynamics::Inertia::mMass

protected

Overall mass.

mMoment

std::array<double, 6> dart::dynamics::Inertia::mMoment

protected

The six parameters of the moment of inertia located at the center of mass.

mSpatialTensor

Eigen::Matrix6d dart::dynamics::Inertia::mSpatialTensor

protected

Cache for generalized spatial inertia of the Body.