crocoddyl  1.7.0
Contact RObot COntrol by Differential DYnamic programming Library (Crocoddyl)
CostModelImpulseCoPPositionTpl< _Scalar > Class Template Reference

Define a center of pressure cost function. More...

#include <crocoddyl/multibody/costs/impulse-cop-position.hpp>

Inheritance diagram for CostModelImpulseCoPPositionTpl< _Scalar >:
Collaboration diagram for CostModelImpulseCoPPositionTpl< _Scalar >:

Public Types

typedef ActivationBoundsTpl< Scalar > ActivationBounds
 
typedef ActivationModelAbstractTpl< Scalar > ActivationModelAbstract
 
typedef ActivationModelQuadraticBarrierTpl< Scalar > ActivationModelQuadraticBarrier
 
typedef CostModelAbstractTpl< Scalar > Base
 
typedef CostDataAbstractTpl< Scalar > CostDataAbstract
 
typedef CostDataImpulseCoPPositionTpl< Scalar > Data
 
typedef DataCollectorAbstractTpl< Scalar > DataCollectorAbstract
 
typedef FrameCoPSupportTpl< Scalar > FrameCoPSupport
 
typedef MathBaseTpl< Scalar > MathBase
 
typedef Eigen::Matrix< Scalar, 4, 6 > Matrix46
 
typedef MathBase::MatrixXs MatrixXs
 
typedef StateMultibodyTpl< Scalar > StateMultibody
 
typedef MathBase::VectorXs VectorXs
 
- Public Types inherited from CostModelAbstractTpl< _Scalar >
typedef ActivationModelAbstractTpl< Scalar > ActivationModelAbstract
 
typedef ActivationModelQuadTpl< Scalar > ActivationModelQuad
 
typedef CostDataAbstractTpl< Scalar > CostDataAbstract
 
typedef DataCollectorAbstractTpl< Scalar > DataCollectorAbstract
 
typedef MathBaseTpl< Scalar > MathBase
 
typedef MathBase::MatrixXs MatrixXs
 
typedef StateAbstractTpl< Scalar > StateAbstract
 
typedef MathBase::VectorXs VectorXs
 

Public Member Functions

 CostModelImpulseCoPPositionTpl (boost::shared_ptr< StateMultibody > state, boost::shared_ptr< ActivationModelAbstract > activation, const FrameCoPSupport &cop_support)
 Initialize the impulse CoP cost model. More...
 
 CostModelImpulseCoPPositionTpl (boost::shared_ptr< StateMultibody > state, const FrameCoPSupport &cop_support)
 Initialize the impulse CoP cost model. More...
 
virtual void calc (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
 Compute the impulse CoP cost. More...
 
virtual void calcDiff (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)
 Compute the derivatives of the impulse CoP cost. More...
 
virtual boost::shared_ptr< CostDataAbstractcreateData (DataCollectorAbstract *const data)
 Create the impulse CoP cost data. More...
 
- Public Member Functions inherited from CostModelAbstractTpl< _Scalar >
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, boost::shared_ptr< ActivationModelAbstract > activation, const std::size_t nu)
 Initialize the cost model. More...
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, boost::shared_ptr< ActivationModelAbstract > activation)
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, const std::size_t nr, const std::size_t nu)
 
 CostModelAbstractTpl (boost::shared_ptr< StateAbstract > state, const std::size_t nr)
 
virtual void calc (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)=0
 Compute the cost value and its residual vector. More...
 
void calc (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
 
virtual void calcDiff (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x, const Eigen::Ref< const VectorXs > &u)=0
 Compute the Jacobian and Hessian of cost and its residual vector. More...
 
void calcDiff (const boost::shared_ptr< CostDataAbstract > &data, const Eigen::Ref< const VectorXs > &x)
 
const boost::shared_ptr< ActivationModelAbstract > & get_activation () const
 Return the activation model.
 
std::size_t get_nu () const
 Return the dimension of the control input.
 
template<class ReferenceType >
ReferenceType get_reference () const
 Return the cost reference.
 
const boost::shared_ptr< StateAbstract > & get_state () const
 Return the state.
 
template<class ReferenceType >
void set_reference (ReferenceType ref)
 Modify the cost reference.
 

Public Attributes

EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar Scalar
 
- Public Attributes inherited from CostModelAbstractTpl< _Scalar >
EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar Scalar
 

Protected Member Functions

virtual void get_referenceImpl (const std::type_info &ti, void *pv) const
 Modify the frame CoP support.
 
virtual void set_referenceImpl (const std::type_info &ti, const void *pv)
 Return the frame CoP support.
 

Additional Inherited Members

- Protected Attributes inherited from CostModelAbstractTpl< _Scalar >
boost::shared_ptr< ActivationModelAbstractactivation_
 Activation model.
 
std::size_t nu_
 Control dimension.
 
boost::shared_ptr< StateAbstractstate_
 State description.
 
VectorXs unone_
 No control vector.
 

Detailed Description

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

Define a center of pressure cost function.

It builds a cost 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 cost 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 cost 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 FrameCoPSupportTpl. The force vector \(\boldsymbol{\lambda}\) and its derivatives are computed by ActionModelImpulseFwdDynamicsTpl. These values are stored in a shared data (i.e. DataCollectorImpulseTpl). Note that this cost function cannot be used with other action models.

See also
ActionModelImpulseFwdDynamicsTpl, DataCollectorImpulseTpl, ActivationModelAbstractTpl, calc(), calcDiff(), createData()

Definition at line 58 of file impulse-cop-position.hpp.

Constructor & Destructor Documentation

◆ CostModelImpulseCoPPositionTpl() [1/2]

CostModelImpulseCoPPositionTpl ( boost::shared_ptr< StateMultibody state,
boost::shared_ptr< ActivationModelAbstract activation,
const FrameCoPSupport cop_support 
)

Initialize the impulse CoP cost model.

Parameters
[in]stateState of the multibody system
[in]activationActivation model
[in]cop_supportId of contact frame and support region of the CoP

◆ CostModelImpulseCoPPositionTpl() [2/2]

CostModelImpulseCoPPositionTpl ( boost::shared_ptr< StateMultibody state,
const FrameCoPSupport cop_support 
)

Initialize the impulse CoP cost model.

We use as default activation model a quadratic barrier ActivationModelQuadraticBarrierTpl, with 0 and inf as lower and upper bounds, respectively.

Parameters
[in]stateState of the multibody system
[in]cop_supportId of contact frame and support region of the cop

Member Function Documentation

◆ calc()

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

Compute the impulse CoP cost.

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

Parameters
[in]dataImpulse CoP data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ calcDiff()

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

Compute the derivatives of the impulse CoP cost.

The CoP derivatives are based on the force derivatives computed by ActionModelImpulseFwdDynamicsTpl which are stored in DataCollectorImpulseTpl.

Parameters
[in]dataImpulse CoP data
[in]xState point \(\mathbf{x}\in\mathbb{R}^{ndx}\)
[in]uControl input \(\mathbf{u}\in\mathbb{R}^{nu}\)

◆ createData()

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

Create the impulse CoP cost data.

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

Parameters
[in]dataShared data (it should be of type DataCollectorImpulseTpl)
Returns
the cost data.

Reimplemented from CostModelAbstractTpl< _Scalar >.


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