Center of pressure residual function. More...

#include <crocoddyl/multibody/residuals/contact-cop-position.hpp>

Public Types
typedef ResidualModelAbstractTpl< Scalar >	Base

typedef CoPSupportTpl< Scalar >	CoPSupport

typedef ResidualDataContactCoPPositionTpl< Scalar >	Data

typedef DataCollectorAbstractTpl< Scalar >	DataCollectorAbstract

typedef MathBaseTpl< Scalar >	MathBase

typedef MathBase::Matrix46s	Matrix46

typedef MathBase::MatrixXs	MatrixXs

typedef ResidualDataAbstractTpl< Scalar >	ResidualDataAbstract

typedef StateMultibodyTpl< Scalar >	StateMultibody

typedef MathBase::VectorXs	VectorXs

Public Member Functions
	ResidualModelContactCoPPositionTpl (boost::shared_ptr< StateMultibody > state, const pinocchio::FrameIndex id, const CoPSupport &cref)
	Initialize the contact CoP residual model. More...

	ResidualModelContactCoPPositionTpl (boost::shared_ptr< StateMultibody > state, const pinocchio::FrameIndex id, const CoPSupport &cref, const std::size_t nu)
	Initialize the contact CoP residual model. More...

virtual void	calc (const boost::shared_ptr< ResidualDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
	Compute the residual vector for nodes that depends only on the state. More...

virtual void	calc (const boost::shared_ptr< ResidualDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
	Compute the contact CoP residual. More...

virtual void	calcDiff (const boost::shared_ptr< ResidualDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
	Compute the Jacobian of the residual functions with respect to the state only. More...

virtual void	calcDiff (const boost::shared_ptr< ResidualDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
	Compute the Jacobians of the contact CoP residual. More...

virtual boost::shared_ptr< ResidualDataAbstract >	createData (DataCollectorAbstract *const data)
	Create the contact CoP residual data. More...

pinocchio::FrameIndex	get_id () const
	Return the reference frame id.

const CoPSupport &	get_reference () const
	Return the reference support region of CoP.

virtual void	print (std::ostream &os) const
	Print relevant information of the cop-position residual. More...

void	set_id (pinocchio::FrameIndex id)
	Modify the reference frame id.

void	set_reference (const CoPSupport &reference)
	Modify the reference support region of CoP.

Public Attributes
EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar	Scalar

Protected Attributes
std::size_t	nu_
	Control dimension.

boost::shared_ptr< StateAbstract >	state_
	State description.

VectorXs	unone_
	No control vector.

Detailed Description

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

Center of pressure residual function.

It builds a residual function that bounds the center of pressure (CoP) for one contact surface to lie inside a certain geometric area defined around the reference contact frame. The residual residual vector is described as \(\mathbf{r}=\mathbf{A}\boldsymbol{\lambda}\geq\mathbf{0}\), where

\[ \mathbf{A}= \begin{bmatrix} 0 & 0 & X/2 & 0 & -1 & 0 \\ 0 & 0 & X/2 & 0 & 1 & 0 \\ 0 & 0 & Y/2 & 1 & 0 & 0 \\ 0 & 0 & Y/2 & -1 & 0 & 0 \end{bmatrix} \]

is the inequality matrix and \(\boldsymbol{\lambda}\) is the reference spatial contact force in the frame coordinate. The CoP lies inside the convex hull of the foot, see eq.(18-19) of https://hal.archives-ouvertes.fr/hal-02108449/document is we have:

\[ \begin{align}\begin{split}\tau^x &\leq Yf^z \\-\tau^x &\leq Yf^z \\\tau^y &\leq Yf^z \\-\tau^y &\leq Yf^z \end{split}\end{align} \]

with \(\boldsymbol{\lambda}= \begin{bmatrix}f^x & f^y & f^z & \tau^x & \tau^y & \tau^z \end{bmatrix}^T\).

The residual is computed, from the residual vector \(\mathbf{r}\), through an user defined activation model. Additionally, the contact frame id, the desired support region for the CoP and the inequality matrix are handled within CoPSupportTpl. The force vector \(\boldsymbol{\lambda}\) and its derivatives are computed by DifferentialActionModelContactFwdDynamicsTpl or ActionModelImpulseFwdDynamicTpl. These values are stored in a shared data (i.e., DataCollectorContactTpl or DataCollectorImpulseTpl). Note that this residual function cannot be used with other action models.

See also: ResidualModelAbstractTpl, calc(), calcDiff(), createData(), DifferentialActionModelContactFwdDynamicsTpl, ActionModelImpulseFwdDynamicTpl, DataCollectorForceTpl

Definition at line 112 of file fwd.hpp.

Constructor & Destructor Documentation

◆ ResidualModelContactCoPPositionTpl() [1/2]

ResidualModelContactCoPPositionTpl	(	boost::shared_ptr< StateMultibody >	state,
		const pinocchio::FrameIndex	id,
		const CoPSupport &	cref,
		const std::size_t	nu
	)

Initialize the contact CoP residual model.

Parameters

[in]	state	State of the multibody system
[in]	id	Reference frame id
[in]	cref	Reference support region of the CoP
[in]	nu	Dimension of control vector

◆ ResidualModelContactCoPPositionTpl() [2/2]

ResidualModelContactCoPPositionTpl	(	boost::shared_ptr< StateMultibody >	state,
		const pinocchio::FrameIndex	id,
		const CoPSupport &	cref
	)

Initialize the contact CoP residual model.

The default nu value is obtained from StateAbstractTpl::get_nv().

Parameters

[in]	state	State of the multibody system
[in]	id	Reference frame id
[in]	cref	Reference support region of the CoP

Member Function Documentation

◆ calc() [1/2]

virtual void calc	(	const boost::shared_ptr< ResidualDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x,
		const Eigen::Ref< const VectorXs > &	u
	)

virtual

Compute the contact CoP residual.

The CoP residual is computed based on the \(\mathbf{A}\) matrix, the force vector is computed by DifferentialActionModelContactFwdDynamicsTpl or ActionModelImpulseFwdDynamicTpl which is stored in DataCollectorContactTpl or DataCollectorImpulseTpl.

Parameters

[in]	data	Contact CoP data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]	u	Control input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calc() [2/2]

virtual void calc	(	const boost::shared_ptr< ResidualDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x
	)

virtual

Compute the residual vector for nodes that depends only on the state.

It updates the residual vector based on the state only (i.e., it ignores the contact forces). This function is used in the terminal nodes of an optimal control problem.

Parameters

[in]	data	Residual data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)

◆ calcDiff() [1/2]

virtual void calcDiff	(	const boost::shared_ptr< ResidualDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x,
		const Eigen::Ref< const VectorXs > &	u
	)

virtual

Compute the Jacobians of the contact CoP residual.

The CoP residual is computed based on the \(\mathbf{A}\) matrix, the force vector is computed by DifferentialActionModelContactFwdDynamicsTpl or ActionModelImpulseFwdDynamicTpl which is stored in DataCollectorContactTpl or DataCollectorImpulseTpl.

Parameters

[in]	data	Contact CoP data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]	u	Control input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calcDiff() [2/2]

virtual void calcDiff	(	const boost::shared_ptr< ResidualDataAbstract > &	data,
		const Eigen::Ref< const VectorXs > &	x
	)

virtual

Compute the Jacobian of the residual functions with respect to the state only.

It updates the Jacobian of the residual function based on the state only (i.e., it ignores the contact forces). This function is used in the terminal nodes of an optimal control problem.

Parameters

[in]	data	Residual data
[in]	x	State point \(\mathbf{x}\in\mathbb{R}^{ndx}\)

◆ createData()

virtual boost::shared_ptr<ResidualDataAbstract> createData ( DataCollectorAbstract *const data )

virtual

Create the contact CoP residual data.

Each residual model has its own data that needs to be allocated. This function returns the allocated data for a predefined residual.

Parameters

[in] data Shared data (it should be of type DataCollectorContactTpl)

Returns: the residual data.

◆ print()

virtual void print ( std::ostream & os ) const

virtual

Print relevant information of the cop-position residual.

Parameters

[out] os Output stream object

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

include/crocoddyl/multibody/fwd.hpp
include/crocoddyl/multibody/residuals/contact-cop-position.hpp

Public Types

Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

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

Constructor & Destructor Documentation

◆ ResidualModelContactCoPPositionTpl() [1/2]

◆ ResidualModelContactCoPPositionTpl() [2/2]

Member Function Documentation

◆ calc() [1/2]

◆ calc() [2/2]

◆ calcDiff() [1/2]

◆ calcDiff() [2/2]

◆ createData()

◆ print()

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