Drake
Drake C++ Documentation
AngleBetweenVectorsConstraint Class Reference

## Detailed Description

Constrains that the angle between a vector a and another vector b is between [θ_lower, θ_upper].

a is fixed to a frame A, while b is fixed to a frame B. Mathematically, if we denote a_unit_A as a expressed in frame A after normalization (a_unit_A has unit length), and b_unit_B as b expressed in frame B after normalization, the constraint is cos(θ_upper) ≤ a_unit_Aᵀ * R_AB * b_unit_B ≤ cos(θ_lower)

#include <drake/multibody/inverse_kinematics/angle_between_vectors_constraint.h>

## Public Member Functions

AngleBetweenVectorsConstraint (const MultibodyPlant< double > *plant, const Frame< double > &frameA, const Eigen::Ref< const Eigen::Vector3d > &a_A, const Frame< double > &frameB, const Eigen::Ref< const Eigen::Vector3d > &b_B, double angle_lower, double angle_upper, systems::Context< double > *plant_context)
Constructs an AngleBetweenVectorsConstraint. More...

AngleBetweenVectorsConstraint (const MultibodyPlant< AutoDiffXd > *plant, const Frame< AutoDiffXd > &frameA, const Eigen::Ref< const Eigen::Vector3d > &a_A, const Frame< AutoDiffXd > &frameB, const Eigen::Ref< const Eigen::Vector3d > &b_B, double angle_lower, double angle_upper, systems::Context< AutoDiffXd > *plant_context)

~AngleBetweenVectorsConstraint () override

Does not allow copy, move, or assignment
AngleBetweenVectorsConstraint (const AngleBetweenVectorsConstraint &)=delete

AngleBetweenVectorsConstraintoperator= (const AngleBetweenVectorsConstraint &)=delete

AngleBetweenVectorsConstraint (AngleBetweenVectorsConstraint &&)=delete

AngleBetweenVectorsConstraintoperator= (AngleBetweenVectorsConstraint &&)=delete

Public Member Functions inherited from Constraint
template<typename DerivedLB , typename DerivedUB >
Constraint (int num_constraints, int num_vars, const Eigen::MatrixBase< DerivedLB > &lb, const Eigen::MatrixBase< DerivedUB > &ub, const std::string &description="")
Constructs a constraint which has num_constraints rows, with an input num_vars x 1 vector. More...

Constraint (int num_constraints, int num_vars)
Constructs a constraint which has num_constraints rows, with an input num_vars x 1 vector, with no bounds. More...

bool CheckSatisfied (const Eigen::Ref< const Eigen::VectorXd > &x, double tol=1E-6) const
Return whether this constraint is satisfied by the given value, x. More...

bool CheckSatisfied (const Eigen::Ref< const AutoDiffVecXd > &x, double tol=1E-6) const

symbolic::Formula CheckSatisfied (const Eigen::Ref< const VectorX< symbolic::Variable >> &x) const

const Eigen::VectorXd & lower_bound () const

const Eigen::VectorXd & upper_bound () const

int num_constraints () const
Number of rows in the output constraint. More...

Constraint (const Constraint &)=delete

Constraintoperator= (const Constraint &)=delete

Constraint (Constraint &&)=delete

Constraintoperator= (Constraint &&)=delete

Public Member Functions inherited from EvaluatorBase
virtual ~EvaluatorBase ()

void Eval (const Eigen::Ref< const Eigen::VectorXd > &x, Eigen::VectorXd *y) const
Evaluates the expression. More...

void Eval (const Eigen::Ref< const AutoDiffVecXd > &x, AutoDiffVecXd *y) const
Evaluates the expression. More...

void Eval (const Eigen::Ref< const VectorX< symbolic::Variable >> &x, VectorX< symbolic::Expression > *y) const
Evaluates the expression. More...

void set_description (const std::string &description)
Set a human-friendly description for the evaluator. More...

const std::string & get_description () const
Getter for a human-friendly description for the evaluator. More...

std::ostream & Display (std::ostream &os, const VectorX< symbolic::Variable > &vars) const
Formats this evaluator into the given stream using vars for the bound decision variable names. More...

std::ostream & Display (std::ostream &os) const
Formats this evaluator into the given stream, without displaying the decision variables it is bound to. More...

std::string ToLatex (const VectorX< symbolic::Variable > &vars, int precision=3) const
Returns a LaTeX string describing this evaluator. More...

int num_vars () const
Getter for the number of variables, namely the number of rows in x, as used in Eval(x, y). More...

int num_outputs () const
Getter for the number of outputs, namely the number of rows in y, as used in Eval(x, y). More...

Set the sparsity pattern of the gradient matrix ∂y/∂x (the gradient of y value in Eval, w.r.t x in Eval) . More...

const std::optional< std::vector< std::pair< int, int > > > & gradient_sparsity_pattern () const
Returns the vector of (row_index, col_index) that contains all the entries in the gradient of Eval function (∂y/∂x) whose value could be non-zero, namely if ∂yᵢ/∂xⱼ could be non-zero, then the pair (i, j) is in gradient_sparsity_pattern. More...

EvaluatorBase (const EvaluatorBase &)=delete

EvaluatorBaseoperator= (const EvaluatorBase &)=delete

EvaluatorBase (EvaluatorBase &&)=delete

EvaluatorBaseoperator= (EvaluatorBase &&)=delete

Protected Member Functions inherited from Constraint
void UpdateLowerBound (const Eigen::Ref< const Eigen::VectorXd > &new_lb)

void UpdateUpperBound (const Eigen::Ref< const Eigen::VectorXd > &new_ub)

void set_bounds (const Eigen::Ref< const Eigen::VectorXd > &new_lb, const Eigen::Ref< const Eigen::VectorXd > &new_ub)
Set the upper and lower bounds of the constraint. More...

virtual bool DoCheckSatisfied (const Eigen::Ref< const Eigen::VectorXd > &x, const double tol) const

virtual bool DoCheckSatisfied (const Eigen::Ref< const AutoDiffVecXd > &x, const double tol) const

virtual symbolic::Formula DoCheckSatisfied (const Eigen::Ref< const VectorX< symbolic::Variable >> &x) const

Protected Member Functions inherited from EvaluatorBase
EvaluatorBase (int num_outputs, int num_vars, const std::string &description="")
Constructs a evaluator. More...

virtual std::ostream & DoDisplay (std::ostream &os, const VectorX< symbolic::Variable > &vars) const
NVI implementation of Display. More...

virtual std::string DoToLatex (const VectorX< symbolic::Variable > &vars, int precision) const

void set_num_outputs (int num_outputs)

## ◆ AngleBetweenVectorsConstraint() [1/4]

 AngleBetweenVectorsConstraint ( const AngleBetweenVectorsConstraint & )
delete

## ◆ AngleBetweenVectorsConstraint() [2/4]

 AngleBetweenVectorsConstraint ( AngleBetweenVectorsConstraint && )
delete

## ◆ AngleBetweenVectorsConstraint() [3/4]

 AngleBetweenVectorsConstraint ( const MultibodyPlant< double > * plant, const Frame< double > & frameA, const Eigen::Ref< const Eigen::Vector3d > & a_A, const Frame< double > & frameB, const Eigen::Ref< const Eigen::Vector3d > & b_B, double angle_lower, double angle_upper, systems::Context< double > * plant_context )

Constructs an AngleBetweenVectorsConstraint.

Parameters
 plant The MultibodyPlant on which the constraint is imposed. plant should be alive during the lifetime of this constraint. frameA The Frame object for frame A. a_A The vector a fixed to frame A, expressed in frame A. frameB The Frame object for frame B. b_B The vector b fixed to frame B, expressed in frameB. angle_lower The lower bound on the angle between a and b. It is denoted as θ_lower in the class documentation. angle_upper The upper bound on the angle between a and b. it is denoted as θ_upper in the class documentation. plant_context The Context that has been allocated for this plant. We will update the context when evaluating the constraint. plant_context should be alive during the lifetime of this constraint.
Precondition
frameA and frameB must belong to plant.
Exceptions
 std::exception if plant is nullptr. std::exception if a_A is close to zero. std::exception if b_B is close to zero. std::exception if angle_lower is negative. std::exception if angle_upper ∉ [angle_lower, π]. std::exception if plant_context is nullptr.

## ◆ AngleBetweenVectorsConstraint() [4/4]

 AngleBetweenVectorsConstraint ( const MultibodyPlant< AutoDiffXd > * plant, const Frame< AutoDiffXd > & frameA, const Eigen::Ref< const Eigen::Vector3d > & a_A, const Frame< AutoDiffXd > & frameB, const Eigen::Ref< const Eigen::Vector3d > & b_B, double angle_lower, double angle_upper, systems::Context< AutoDiffXd > * plant_context )

## ◆ ~AngleBetweenVectorsConstraint()

 ~AngleBetweenVectorsConstraint ( )
override

## ◆ operator=() [1/2]

 AngleBetweenVectorsConstraint& operator= ( const AngleBetweenVectorsConstraint & )
delete

## ◆ operator=() [2/2]

 AngleBetweenVectorsConstraint& operator= ( AngleBetweenVectorsConstraint && )
delete

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