crocoddyl  1.9.0
Contact RObot COntrol by Differential DYnamic programming Library (Crocoddyl)
ResidualModelContactCoPPositionTpl< _Scalar > Class Template Reference

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< ResidualDataAbstractcreateData (DataCollectorAbstract *const data)
 Create the contact CoP residual data. More...
 
pinocchio::FrameIndex get_id () const
 Return the reference frame id.
 
const CoPSupportget_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< StateAbstractstate_
 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]stateState of the multibody system
[in]idReference frame id
[in]crefReference support region of the CoP
[in]nuDimension 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]stateState of the multibody system
[in]idReference frame id
[in]crefReference 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]dataContact CoP data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl 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]dataResidual data
[in]xState 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]dataContact CoP data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl 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]dataResidual data
[in]xState 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]dataShared 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]osOutput stream object

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