Template Class WrenchConeTpl

Defined in File wrench-cone.hpp

Class Documentation

template<typename _Scalar> class WrenchConeTpl

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

Public Types

typedef MathBaseTpl<Scalar> MathBase

typedef MathBase::Vector2s Vector2s

typedef MathBase::Vector3s Vector3s

typedef MathBase::Matrix3s Matrix3s

typedef MathBase::Matrix6s Matrix6s

typedef MathBase::VectorXs VectorXs

typedef MathBase::MatrixXs MatrixXs

typedef MathBase::MatrixX3s MatrixX3s

typedef MathBase::MatrixX6s MatrixX6s

typedef MathBase::Quaternions Quaternions

Public Functions

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:

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

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.

Parameters:: cone – [in] Wrench cone

explicit WrenchConeTpl(): Initialize the wrench cone.

~WrenchConeTpl()

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.

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()))

template<typename NewScalar> WrenchConeTpl<NewScalar> cast() const

Cast the wrench cone to a different scalar type.

It is useful for operations requiring different precision or scalar types.

Template Parameters:: NewScalar – The new scalar type to cast to.
Returns:: WrenchConeTpl<NewScalar> A wrench cone with the new scalar type.

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

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

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

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

const Scalar get_mu() const: Return friction coefficient.

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

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

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

void set_R(const Matrix3s &R)

Modify the rotation matrix that defines the cone orientation w.r.t. the inertial frame.