Define a contact force residual function. More...

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

Public Types
typedef ResidualModelAbstractTpl< Scalar >	Base

typedef ResidualDataContactForceTpl< Scalar >	Data

typedef DataCollectorAbstractTpl< Scalar >	DataCollectorAbstract

typedef pinocchio::ForceTpl< Scalar >	Force

typedef MathBaseTpl< Scalar >	MathBase

typedef MathBase::MatrixXs	MatrixXs

typedef ResidualDataAbstractTpl< Scalar >	ResidualDataAbstract

typedef StateMultibodyTpl< Scalar >	StateMultibody

typedef MathBase::VectorXs	VectorXs

Public Member Functions
	ResidualModelContactForceTpl (boost::shared_ptr< StateMultibody > state, const pinocchio::FrameIndex id, const Force &fref, const std::size_t nc)
	Initialize the contact force residual model. More...

	ResidualModelContactForceTpl (boost::shared_ptr< StateMultibody > state, const pinocchio::FrameIndex id, const Force &fref, const std::size_t nc, const std::size_t nu)
	Initialize the contact force 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 force 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 derivatives of the contact force residual. More...

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

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

const Force &	get_reference () const
	Return the reference spatial contact force in the contact coordinates.

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

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

void	set_reference (const Force &reference)
	Modify the reference spatial contact force in the contact coordinates.

Public Attributes
EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar	Scalar

Protected Attributes
std::size_t	nr_
	Residual vector dimension.

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::ResidualModelContactForceTpl< _Scalar >

Define a contact force residual function.

This residual function is defined as \(\mathbf{r}=\boldsymbol{\lambda}-\boldsymbol{\lambda}^*\), where \(\boldsymbol{\lambda}, \boldsymbol{\lambda}^*\) are the current and reference spatial forces, respectively. The current spatial forces \(\boldsymbol{\lambda}\in\mathbb{R}^{nc}\) is computed by DifferentialActionModelContactFwdDynamicsTpl or ActionModelImpulseFwdDynamicTpl, with nc as the dimension of the contact.

Both residual and residual Jacobians are computed analytically, where the force vector \(\boldsymbol{\lambda}\) and its Jacobians \(\left(\frac{\partial\boldsymbol{\lambda}}{\partial\mathbf{x}}, \frac{\partial\boldsymbol{\lambda}}{\partial\mathbf{u}}\right)\) 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, DataCollectorContactTpl, DataCollectorImpulseTpl

Definition at line 102 of file fwd.hpp.

Constructor & Destructor Documentation

◆ ResidualModelContactForceTpl() [1/2]

ResidualModelContactForceTpl	(	boost::shared_ptr< StateMultibody >	state,
		const pinocchio::FrameIndex	id,
		const Force &	fref,
		const std::size_t	nc,
		const std::size_t	nu
	)

Initialize the contact force residual model.

Parameters

[in]	state	Multibody state
[in]	id	Reference frame id
[in]	fref	Reference spatial contact force in the contact coordinates
[in]	nc	Dimension of the contact force (nc <= 6)
[in]	nu	Dimension of control vector

◆ ResidualModelContactForceTpl() [2/2]

ResidualModelContactForceTpl	(	boost::shared_ptr< StateMultibody >	state,
		const pinocchio::FrameIndex	id,
		const Force &	fref,
		const std::size_t	nc
	)

Initialize the contact force residual model.

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

Parameters

[in]	state	Multibody state
[in]	id	Reference frame id
[in]	fref	Reference spatial contact force in the contact coordinates
[in]	nc	Dimension of the contact force (nc <= 6)

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 force 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 force 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 derivatives of the contact force 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 force 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 force residual data.

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 contact-force 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-force.hpp

Public Types

Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

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

Constructor & Destructor Documentation

◆ ResidualModelContactForceTpl() [1/2]

◆ ResidualModelContactForceTpl() [2/2]

Member Function Documentation

◆ calc() [1/2]

◆ calc() [2/2]

◆ calcDiff() [1/2]

◆ calcDiff() [2/2]

◆ createData()

◆ print()

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