Public Types | Public Member Functions | Private Attributes | List of all members
towr::ForceConstraint Class Reference

Ensures foot force that is unilateral and inside friction cone. More...

#include <force_constraint.h>

Inheritance diagram for towr::ForceConstraint:
Inheritance graph

Public Types

using EE = uint
using Vector3d = Eigen::Vector3d
- Public Types inherited from ifopt::ConstraintSet
typedef std::shared_ptr< ConstraintSetPtr
typedef Composite::Ptr VariablesPtr
- Public Types inherited from ifopt::Component
typedef Eigen::SparseMatrix< double, Eigen::RowMajor > Jacobian
typedef std::shared_ptr< ComponentPtr
typedef std::vector< BoundsVecBound
typedef Eigen::VectorXd VectorXd

Public Member Functions

void FillJacobianBlock (std::string var_set, Jacobian &) const override
 ForceConstraint (const HeightMap::Ptr &terrain, double force_limit_in_normal_direction, EE endeffector_id)
 Constructs a force contraint. More...
VecBound GetBounds () const override
VectorXd GetValues () const override
void InitVariableDependedQuantities (const VariablesPtr &x) override
virtual ~ForceConstraint ()=default
- Public Member Functions inherited from ifopt::ConstraintSet
 ConstraintSet (int n_constraints, const std::string &name)
Jacobian GetJacobian () const final
void LinkWithVariables (const VariablesPtr &x)
virtual ~ConstraintSet ()=default
- Public Member Functions inherited from ifopt::Component
 Component (int num_rows, const std::string &name)
std::string GetName () const
int GetRows () const
virtual void Print (double tolerance, int &index_start) const
void SetRows (int num_rows)
virtual ~Component ()=default

Private Attributes

EE ee_
 The endeffector force to be constrained. More...
NodesVariablesPhaseBased::Ptr ee_force_
 the current xyz foot forces. More...
NodesVariablesPhaseBased::Ptr ee_motion_
 the current xyz foot positions. More...
double fn_max_
 force limit in normal direction. More...
double mu_
 friction coeff between robot feet and terrain. More...
int n_constraints_per_node_
 number of constraint for each node. More...
std::vector< int > pure_stance_force_node_ids_
HeightMap::Ptr terrain_
 gradient information at every position (x,y). More...

Additional Inherited Members

- Static Public Attributes inherited from ifopt::Component
static const int kSpecifyLater
- Protected Member Functions inherited from ifopt::ConstraintSet
const VariablesPtr GetVariables () const

Detailed Description

Ensures foot force that is unilateral and inside friction cone.

This class is responsible for constraining the endeffector xyz-forces to only push into the terrain and additionally stay inside the friction cone according to the current slope.

In order to keep the constraint linear and simple for the solver to solve, we approximate the friction cone by a 4-sided pyramid.

Attention: Constraint is enforced only at the spline nodes. In between violations of this constraint can occur.

Definition at line 55 of file force_constraint.h.

Member Typedef Documentation

Definition at line 58 of file force_constraint.h.

using towr::ForceConstraint::Vector3d = Eigen::Vector3d

Definition at line 57 of file force_constraint.h.

Constructor & Destructor Documentation

towr::ForceConstraint::ForceConstraint ( const HeightMap::Ptr terrain,
double  force_limit_in_normal_direction,
EE  endeffector_id 

Constructs a force contraint.

terrainThe gradient information of the terrain for friction cone.
force_limit_in_normal_directionMaximum pushing force [N].
endeffector_idWhich endeffector force should be constrained.

Definition at line 37 of file

virtual towr::ForceConstraint::~ForceConstraint ( )

Member Function Documentation

void towr::ForceConstraint::FillJacobianBlock ( std::string  var_set,
Jacobian jac 
) const

Implements ifopt::ConstraintSet.

Definition at line 108 of file

ForceConstraint::VecBound towr::ForceConstraint::GetBounds ( ) const

Implements ifopt::Component.

Definition at line 92 of file

Eigen::VectorXd towr::ForceConstraint::GetValues ( ) const

Implements ifopt::Component.

Definition at line 63 of file

void towr::ForceConstraint::InitVariableDependedQuantities ( const VariablesPtr x)

Definition at line 51 of file

Member Data Documentation

EE towr::ForceConstraint::ee_

The endeffector force to be constrained.

Definition at line 85 of file force_constraint.h.

NodesVariablesPhaseBased::Ptr towr::ForceConstraint::ee_force_

the current xyz foot forces.

Definition at line 78 of file force_constraint.h.

NodesVariablesPhaseBased::Ptr towr::ForceConstraint::ee_motion_

the current xyz foot positions.

Definition at line 79 of file force_constraint.h.

double towr::ForceConstraint::fn_max_

force limit in normal direction.

Definition at line 82 of file force_constraint.h.

double towr::ForceConstraint::mu_

friction coeff between robot feet and terrain.

Definition at line 83 of file force_constraint.h.

int towr::ForceConstraint::n_constraints_per_node_

number of constraint for each node.

Definition at line 84 of file force_constraint.h.

std::vector<int> towr::ForceConstraint::pure_stance_force_node_ids_

The are those Hermite-nodes that shape the polynomial during the stance phases, while all the others are already set to zero force (swing)

Definition at line 91 of file force_constraint.h.

HeightMap::Ptr towr::ForceConstraint::terrain_

gradient information at every position (x,y).

Definition at line 81 of file force_constraint.h.

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

Author(s): Alexander W. Winkler
autogenerated on Fri Apr 2 2021 02:14:16