Drake
GazeTargetConstraint Class Reference

Detailed Description

Constrains a target point T to be within a cone K.

The point T ("T" stands for "target") is fixed in a frame B, with position p_BT. The cone originates from a point S ("S" stands for "source"), fixed in frame A with position p_AS, with the axis of the cone being n, also fixed in frame A. The half angle of the cone is θ. A common usage of this constraint is that a camera should gaze at some target; namely the target falls within a gaze cone, originating from the camera eye.

Mathematically the constraint is p_ST_Aᵀ * n_unit_A ≥ 0 (p_ST_Aᵀ * n_unit_A)² ≥ (cosθ)²p_ST_Aᵀ * p_ST_A where p_ST_A is the vector from S to T, expressed in frame A. n_unit_A is the unit length directional vector representing the center ray of the cone.

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

Public Member Functions

GazeTargetConstraint (const MultibodyPlant< double > *plant, const Frame< double > &frameA, const Eigen::Ref< const Eigen::Vector3d > &p_AS, const Eigen::Ref< const Eigen::Vector3d > &n_A, const Frame< double > &frameB, const Eigen::Ref< const Eigen::Vector3d > &p_BT, double cone_half_angle, systems::Context< double > *plant_context)

GazeTargetConstraint (const MultibodyPlant< AutoDiffXd > *plant, const Frame< AutoDiffXd > &frameA, const Eigen::Ref< const Eigen::Vector3d > &p_AS, const Eigen::Ref< const Eigen::Vector3d > &n_A, const Frame< AutoDiffXd > &frameB, const Eigen::Ref< const Eigen::Vector3d > &p_BT, double cone_half_angle, systems::Context< AutoDiffXd > *plant_context)

~GazeTargetConstraint () override

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

GazeTargetConstraintoperator= (const GazeTargetConstraint &)=delete

GazeTargetConstraint (GazeTargetConstraint &&)=delete

GazeTargetConstraintoperator= (GazeTargetConstraint &&)=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...

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...

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) . More...

const 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)
Updates the lower bound. More...

void UpdateUpperBound (const Eigen::Ref< const Eigen::VectorXd > &new_ub)
Updates the upper bound. More...

void set_bounds (const Eigen::Ref< const Eigen::VectorXd > &lower_bound, const Eigen::Ref< const Eigen::VectorXd > &upper_bound)
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...

void set_num_outputs (int num_outputs)

◆ GazeTargetConstraint() [1/4]

 GazeTargetConstraint ( const GazeTargetConstraint & )
delete

◆ GazeTargetConstraint() [2/4]

 GazeTargetConstraint ( GazeTargetConstraint && )
delete

◆ GazeTargetConstraint() [3/4]

 GazeTargetConstraint ( const MultibodyPlant< double > * plant, const Frame< double > & frameA, const Eigen::Ref< const Eigen::Vector3d > & p_AS, const Eigen::Ref< const Eigen::Vector3d > & n_A, const Frame< double > & frameB, const Eigen::Ref< const Eigen::Vector3d > & p_BT, double cone_half_angle, systems::Context< double > * plant_context )
Parameters
 plant The MultibodyPlant on which the constraint is imposed. plant should be alive during the lifetime of this constraint. frameA The frame to which the gaze cone is fixed. p_AS The position of the cone source point S, measured and expressed in frame A. n_A The directional vector representing the center ray of the cone, expressed in frame A. frameB The frame to which the target point T is fixed. p_BT The position of the target point T, measured and expressed in frame B. cone_half_angle The half angle of the cone. We denote it as θ in the class documentation. cone_half_angle is in radians. 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::invalid_argument if plant is nullptr. std::invalid_argument if n_A is close to zero. std::invalid_argument if cone_half_angle ∉ [0, π/2]. std::invalid_argument if plant_context is nullptr.

◆ GazeTargetConstraint() [4/4]

 GazeTargetConstraint ( const MultibodyPlant< AutoDiffXd > * plant, const Frame< AutoDiffXd > & frameA, const Eigen::Ref< const Eigen::Vector3d > & p_AS, const Eigen::Ref< const Eigen::Vector3d > & n_A, const Frame< AutoDiffXd > & frameB, const Eigen::Ref< const Eigen::Vector3d > & p_BT, double cone_half_angle, systems::Context< AutoDiffXd > * plant_context )

Construct from MultibodyPlant<AutoDiffXd> instead of MultibodyPlant<double>.

◆ ~GazeTargetConstraint()

 ~GazeTargetConstraint ( )
override

◆ operator=() [1/2]

 GazeTargetConstraint& operator= ( const GazeTargetConstraint & )
delete

◆ operator=() [2/2]

 GazeTargetConstraint& operator= ( GazeTargetConstraint && )
delete

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