This class encapsulates a wrench cone. More...

#include <wrench-cone.hpp>

Public Types
typedef MathBaseTpl< Scalar >	MathBase

typedef MathBase::Matrix3s	Matrix3s

typedef MathBase::Matrix6s	Matrix6s

typedef MathBase::MatrixX3s	MatrixX3s

typedef MathBase::MatrixX6s	MatrixX6s

typedef MathBase::MatrixXs	MatrixXs

typedef MathBase::Quaternions	Quaternions

typedef MathBase::Vector2s	Vector2s

typedef MathBase::Vector3s	Vector3s

typedef MathBase::VectorXs	VectorXs

Public Member Functions
	WrenchConeTpl ()
	Initialize the wrench cone.

	WrenchConeTpl (const Matrix3s &R, const Scalar mu, const Vector2s &box, const std::size_t nf=4, const bool inner_appr=true, const Scalar min_nforce=Scalar(0.), const Scalar max_nforce=std::numeric_limits< Scalar >::infinity())
	Initialize the wrench cone. More...

	DEPRECATED ("Use constructor that includes inner_appr", WrenchConeTpl(const Matrix3s &R, const Scalar mu, const Vector2s &box, std::size_t nf, const Scalar min_nforce, const Scalar max_nforce=std::numeric_limits< Scalar >::infinity());) WrenchConeTpl(const WrenchConeTpl< Scalar > &cone)
	Initialize the wrench cone. More...

	DEPRECATED ("Use update().", void update(const Matrix3s &R, const Scalar mu, const Vector2s &box, const Scalar min_nforce=Scalar(0.), const Scalar max_nforce=std::numeric_limits< Scalar >::infinity()))

const MatrixX6s &	get_A () const
	Return the matrix of wrench cone.

const Vector2s &	get_box () const
	Return dimension of the foot surface dim = (length, width)

bool	get_inner_appr () const
	Return the label that describes the type of friction cone approximation (inner/outer)

const VectorXs &	get_lb () const
	Return the lower bound of inequalities.

const Scalar	get_max_nforce () const
	Return the maximum normal force.

const Scalar	get_min_nforce () const
	Return the minimum normal force.

const Scalar	get_mu () const
	Return friction coefficient.

std::size_t	get_nf () const
	Return the number of facets.

const Matrix3s &	get_R () const
	Return the rotation matrix that defines the cone orientation w.r.t. the inertial frame.

const VectorXs &	get_ub () const
	Return the upper bound of inequalities.

WrenchConeTpl< Scalar > &	operator= (const WrenchConeTpl< Scalar > &other)

void	set_box (const Vector2s &box)
	Modify dimension of the foot surface dim = (length, width) More...

void	set_inner_appr (const bool inner_appr)
	Modify the label that describes the type of friction cone approximation (inner/outer) More...

void	set_max_nforce (const Scalar max_nforce)
	Modify the maximum normal force. More...

void	set_min_nforce (const Scalar min_nforce)
	Modify the minium normal force. More...

void	set_mu (const Scalar mu)
	Modify friction coefficient. More...

void	set_R (const Matrix3s &R)
	Modify the rotation matrix that defines the cone orientation w.r.t. the inertial frame. More...

void	update ()
	Update the matrix of wrench cone inequalities in the world frame. More...

Public Attributes
EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar	Scalar

Friends
template<class Scalar >
std::ostream &	operator<< (std::ostream &os, const WrenchConeTpl< Scalar > &X)

Detailed Description

template<typename _Scalar>
class crocoddyl::WrenchConeTpl< _Scalar >

This class encapsulates a wrench cone.

A wrench cone is a 6D polyhedral convex cone that characterizes feasible contact wrench. The wrench cone is derived in the case of rectangular support areas, which is of practical importance since most humanoid robot feet can be adequately approximated by rectangles. For more details read: S. Caron et. al. Stability of surface contacts for humanoid robots: Closed-form formulae of the Contact Wrench Cone for rectangular support areas (https://hal.archives-ouvertes.fr/hal-02108449/document)

/sa FrictionConeTpl, CoPSupportTpl

Definition at line 32 of file wrench-cone.hpp.

Constructor & Destructor Documentation

◆ WrenchConeTpl()

WrenchConeTpl	(	const Matrix3s &	R,
		const Scalar	mu,
		const Vector2s &	box,
		const std::size_t	nf = `4`,
		const bool	inner_appr = `true`,
		const Scalar	min_nforce = `Scalar(0.)`,
		const Scalar	max_nforce = `std::numeric_limits< Scalar >::infinity()`
	)

Initialize the wrench cone.

Parameters

[in]	R	Rotation matrix that defines the cone orientation w.r.t. the inertial frame
[in]	mu	Friction coefficient
[in]	box	Dimension of the foot surface dim = (length, width)
[in]	nf	Number of facets (default 4)
[in]	inner_appr	Label that describes the type of friction cone approximation (inner/outer)
[in]	min_nforce	Minimum normal force (default 0.)
[in]	max_nforce	Maximum normal force (default inf number))

Member Function Documentation

◆ DEPRECATED()

DEPRECATED	(	"Use constructor that includes inner_appr"	,
		WrenchConeTpl< _Scalar >(const Matrix3s &R, const Scalar mu, const Vector2s &box, std::size_t nf, const Scalar min_nforce, const Scalar max_nforce=std::numeric_limits< Scalar >::infinity());
	)		const &

Initialize the wrench cone.

Parameters

[in] cone Wrench cone

◆ update()

void update ( )

Update the matrix of wrench cone inequalities in the world frame.

This matrix-vector pair describes the linearized Coulomb friction model as follow: \( -ub \leq A \times w \leq -lb \), where wrench, \( w \), is expressed in the inertial frame located at the center of the rectangular foot contact area (length, width) with axes parallel to those of the world frame.