Template Class ContactModelMultipleTpl

Class Documentation

template<typename _Scalar>
class ContactModelMultipleTpl

Define a stack of contact models.

The contact models can be defined with active and inactive status. The idea behind this design choice is to be able to create a mechanism that allocates the entire data needed for the computations. Then, there are designed routines that update the only active contacts.

Public Types

typedef MathBaseTpl<Scalar> MathBase
typedef StateMultibodyTpl<Scalar> StateMultibody
typedef ContactDataAbstractTpl<Scalar> ContactDataAbstract
typedef ContactDataMultipleTpl<Scalar> ContactDataMultiple
typedef ContactModelAbstractTpl<Scalar> ContactModelAbstract
typedef ContactItemTpl<Scalar> ContactItem
typedef MathBase::Vector2s Vector2s
typedef MathBase::Vector3s Vector3s
typedef MathBase::VectorXs VectorXs
typedef MathBase::MatrixXs MatrixXs
typedef std::map<std::string, std::shared_ptr<ContactItem>> ContactModelContainer
typedef std::map<std::string, std::shared_ptr<ContactDataAbstract>> ContactDataContainer
typedef pinocchio::container::aligned_vector<pinocchio::ForceTpl<Scalar>>::iterator ForceIterator

Public Functions

ContactModelMultipleTpl(std::shared_ptr<StateMultibody> state, const std::size_t nu)

Initialize the multi-contact model.

Parameters:

  • state – [in] Multibody state

  • nu – [in] Dimension of control vector

ContactModelMultipleTpl(std::shared_ptr<StateMultibody> state)

Initialize the multi-contact model.

Parameters:

state – [in] Multibody state

~ContactModelMultipleTpl()
void addContact(const std::string &name, std::shared_ptr<ContactModelAbstract> contact, const bool active = true)

Add contact item.

Note that the memory is allocated for inactive contacts as well.

Parameters:

  • name – [in] Contact name

  • contact – [in] Contact model

  • active – [in] Contact status (active by default)

void removeContact(const std::string &name)

Remove contact item.

Parameters:

name – [in] Contact name

void changeContactStatus(const std::string &name, const bool active)

Change the contact status.

Parameters:

  • name – [in] Contact name

  • active – [in] Contact status (True for active)

void calc(const std::shared_ptr<ContactDataMultiple> &data, const Eigen::Ref<const VectorXs> &x)

Compute the contact Jacobian and contact acceleration.

Parameters:

  • data – [in] Multi-contact data

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

void calcDiff(const std::shared_ptr<ContactDataMultiple> &data, const Eigen::Ref<const VectorXs> &x)

Compute the derivatives of the contact holonomic constraint.

Parameters:

  • data – [in] Multi-contact data

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

void updateAcceleration(const std::shared_ptr<ContactDataMultiple> &data, const VectorXs &dv) const

Update the constrained system acceleration.

Parameters:

  • data – [in] Multi-contact data

  • dv – [in] Constrained system acceleration \(\dot{\mathbf{v}}\in\mathbb{R}^{nv}\)

void updateForce(const std::shared_ptr<ContactDataMultiple> &data, const VectorXs &force)

Update the spatial force defined in frame coordinate.

Parameters:

  • data – [in] Multi-contact data

  • force – [in] Spatial force defined in frame coordinate \({}^o\underline{\boldsymbol{\lambda}}_c\in\mathbb{R}^{nc}\)

void updateAccelerationDiff(const std::shared_ptr<ContactDataMultiple> &data, const MatrixXs &ddv_dx) const

Update the Jacobian of the constrained system acceleration.

Parameters:

  • data – [in] Multi-contact data

  • ddv_dx – [in] Jacobian of the system acceleration in generalized coordinates \(\frac{\partial\dot{\mathbf{v}}}{\partial\mathbf{x}}\in\mathbb{R}^{nv\times ndx}\)

void updateForceDiff(const std::shared_ptr<ContactDataMultiple> &data, const MatrixXs &df_dx, const MatrixXs &df_du) const

Update the Jacobian of the spatial force defined in frame coordinate.

Parameters:

  • data – [in] Multi-contact data

  • df_dx – [in] Jacobian of the spatial impulse defined in frame coordinate \(\frac{\partial{}^o\underline{\boldsymbol{\lambda}}_c}{\partial\mathbf{x}}\in\mathbb{R}^{nc\times{ndx}}\)

  • df_du – [in] Jacobian of the spatial impulse defined in frame coordinate \(\frac{\partial{}^o\underline{\boldsymbol{\lambda}}_c}{\partial\mathbf{u}}\in\mathbb{R}^{nc\times{nu}}\)

void updateRneaDiff(const std::shared_ptr<ContactDataMultiple> &data, pinocchio::DataTpl<Scalar> &pinocchio) const

Update the RNEA derivatives dtau_dq by adding the skew term (necessary for contacts expressed in LOCAL_WORLD_ALIGNED / WORLD)

To learn more about the computation of the contact derivatives in different frames see https://hal.science/hal-03758989/document.

Parameters:

  • data – [in] Multi-contact data

  • pinocchio – [in] Pinocchio data

std::shared_ptr<ContactDataMultiple> createData(pinocchio::DataTpl<Scalar> *const data)

Create the multi-contact data.

Parameters:

data – [in] Pinocchio data

Returns:

the multi-contact data.

template<typename NewScalar>
ContactModelMultipleTpl<NewScalar> cast() const

Cast the multi-contact model 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:

ContactModelMultipleTpl<NewScalar> A multi-contact model with the new scalar type.

const std::shared_ptr<StateMultibody> &get_state() const

Return the multibody state.

const ContactModelContainer &get_contacts() const

Return the contact models.

std::size_t get_nc() const

Return the dimension of active contacts.

std::size_t get_nc_total() const

Return the dimension of all contacts.

std::size_t get_nu() const

Return the dimension of control vector.

const std::set<std::string> &get_active_set() const

Return the names of the set of active contacts.

const std::set<std::string> &get_inactive_set() const

Return the names of the set of inactive contacts.

bool getContactStatus(const std::string &name) const

Return the status of a given contact name.

bool getComputeAllContacts() const

Return the type of contact computation.

True for all contacts, otherwise false for active contacts

void setComputeAllContacts(const bool status)

Set the tyoe of contact computation: all or active contacts.

Parameters:

status – Type of contact computation (true for all contacts and false for active contacts)

Public Members

EIGEN_MAKE_ALIGNED_OPERATOR_NEW typedef _Scalar Scalar

Friends

template<class Scalar>
friend std::ostream &operator<<(std::ostream &os, const ContactModelMultipleTpl<Scalar> &model)

Print information on the contact models.