Detailed Description

Constrain that the distance between a point P1 on frame B1 and another point P2 on frame B2 is within a range [distance_lower, distance_upper].

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

Public Member Functions
	PointToPointDistanceConstraint (const MultibodyPlant< double > plant, const Frame< double > &frame1, const Eigen::Ref< const Eigen::Vector3d > &p_B1P1, const Frame< double > &frame2, const Eigen::Ref< const Eigen::Vector3d > &p_B2P2, double distance_lower, double distance_upper, systems::Context< double > plant_context)
	Constrain that the distance between a point P1 attached to frame B1 and another point P2 attached to frame B2 is within the range [distance_lower, distance_upper].
	PointToPointDistanceConstraint (const MultibodyPlant< AutoDiffXd > plant, const Frame< AutoDiffXd > &frame1, const Eigen::Ref< const Eigen::Vector3d > &p_B1P1, const Frame< AutoDiffXd > &frame2, const Eigen::Ref< const Eigen::Vector3d > &p_B2P2, double distance_lower, double distance_upper, systems::Context< AutoDiffXd > plant_context)
	Overloaded constructor.
	~PointToPointDistanceConstraint () override
Does not allow copy, move, or assignment
	PointToPointDistanceConstraint (const PointToPointDistanceConstraint &)=delete
PointToPointDistanceConstraint &	operator= (const PointToPointDistanceConstraint &)=delete
	PointToPointDistanceConstraint (PointToPointDistanceConstraint &&)=delete
PointToPointDistanceConstraint &	operator= (PointToPointDistanceConstraint &&)=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.
	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.
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.
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.
	Constraint (const Constraint &)=delete
Constraint &	operator= (const Constraint &)=delete
	Constraint (Constraint &&)=delete
Constraint &	operator= (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.
void	Eval (const Eigen::Ref< const AutoDiffVecXd > &x, AutoDiffVecXd *y) const
	Evaluates the expression.
void	Eval (const Eigen::Ref< const VectorX< symbolic::Variable > > &x, VectorX< symbolic::Expression > *y) const
	Evaluates the expression.
void	set_description (const std::string &description)
	Set a human-friendly description for the evaluator.
const std::string &	get_description () const
	Getter for a human-friendly description for the evaluator.
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.
std::ostream &	Display (std::ostream &os) const
	Formats this evaluator into the given stream, without displaying the decision variables it is bound to.
std::string	ToLatex (const VectorX< symbolic::Variable > &vars, int precision=3) const
	Returns a LaTeX string describing this evaluator.
int	num_vars () const
	Getter for the number of variables, namely the number of rows in x, as used in Eval(x, y).
int	num_outputs () const
	Getter for the number of outputs, namely the number of rows in y, as used in Eval(x, y).
void	SetGradientSparsityPattern (const std::vector< std::pair< int, int > > &gradient_sparsity_pattern)
	Set the sparsity pattern of the gradient matrix ∂y/∂x (the gradient of y value in Eval, w.r.t x in Eval) .
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.
bool	is_thread_safe () const
	Returns whether it is safe to call Eval in parallel.
	EvaluatorBase (const EvaluatorBase &)=delete
EvaluatorBase &	operator= (const EvaluatorBase &)=delete
	EvaluatorBase (EvaluatorBase &&)=delete
EvaluatorBase &	operator= (EvaluatorBase &&)=delete

Additional Inherited Members
Protected Member Functions inherited from Constraint
void	UpdateLowerBound (const Eigen::Ref< const Eigen::VectorXd > &new_lb)
	Updates the lower bound.
void	UpdateUpperBound (const Eigen::Ref< const Eigen::VectorXd > &new_ub)
	Updates the upper bound.
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.
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.
virtual std::ostream &	DoDisplay (std::ostream &os, const VectorX< symbolic::Variable > &vars) const
	NVI implementation of Display.
virtual std::string	DoToLatex (const VectorX< symbolic::Variable > &vars, int precision) const
void	set_num_outputs (int num_outputs)
void	set_is_thread_safe (bool is_thread_safe)

Constructor & Destructor Documentation

◆ PointToPointDistanceConstraint() [1/4]

PointToPointDistanceConstraint ( const PointToPointDistanceConstraint & )

delete

◆ PointToPointDistanceConstraint() [2/4]

PointToPointDistanceConstraint ( PointToPointDistanceConstraint && )

delete

◆ PointToPointDistanceConstraint() [3/4]

PointToPointDistanceConstraint	(	const MultibodyPlant< double > *	plant,
		const Frame< double > &	frame1,
		const Eigen::Ref< const Eigen::Vector3d > &	p_B1P1,
		const Frame< double > &	frame2,
		const Eigen::Ref< const Eigen::Vector3d > &	p_B2P2,
		double	distance_lower,
		double	distance_upper,
		systems::Context< double > *	plant_context )

Constrain that the distance between a point P1 attached to frame B1 and another point P2 attached to frame B2 is within the range [distance_lower, distance_upper].

Mathematically, we impose the constraint distance_lower² <= distance(P1, P2)² <= distance_upper². We impose the constraint on the distance square instead of distance directly, because the gradient of distance is not well defined at distance=0, the gradient of the distance square is well defined everywhere.

Parameters

plant	The MultibodyPlant on which the constraint is imposed. plant should be alive during the lifetime of this constraint.
frame1	The frame in which P1 is attached to.
p_B1P1	The position of P1 measured and expressed in B1.
frame2	The frame in which P2 is attached to.
p_B2P2	The position of P2 measured and expressed in B2.
distance_lower	The lower bound on the distance, must be non-negative.
distance_upper	The upper bound on the distance, must be non-negative.
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.

◆ PointToPointDistanceConstraint() [4/4]

PointToPointDistanceConstraint	(	const MultibodyPlant< AutoDiffXd > *	plant,
		const Frame< AutoDiffXd > &	frame1,
		const Eigen::Ref< const Eigen::Vector3d > &	p_B1P1,
		const Frame< AutoDiffXd > &	frame2,
		const Eigen::Ref< const Eigen::Vector3d > &	p_B2P2,
		double	distance_lower,
		double	distance_upper,
		systems::Context< AutoDiffXd > *	plant_context )

Overloaded constructor.

Same as the constructor with the double version (using MultibodyPlant<double> and Context<double>), except the gradient of the constraint is computed from autodiff.

◆ ~PointToPointDistanceConstraint()

~PointToPointDistanceConstraint ( )

override

Member Function Documentation

◆ operator=() [1/2]

PointToPointDistanceConstraint & operator= ( const PointToPointDistanceConstraint & )

delete

◆ operator=() [2/2]

PointToPointDistanceConstraint & operator= ( PointToPointDistanceConstraint && )

delete

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

drake/multibody/inverse_kinematics/point_to_point_distance_constraint.h

Detailed Description

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ PointToPointDistanceConstraint() [1/4]

◆ PointToPointDistanceConstraint() [2/4]

◆ PointToPointDistanceConstraint() [3/4]

◆ PointToPointDistanceConstraint() [4/4]

◆ ~PointToPointDistanceConstraint()

Member Function Documentation

◆ operator=() [1/2]

◆ operator=() [2/2]