Detailed Description

Contains parameters for differential inverse kinematics.

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

Public Member Functions
	DifferentialInverseKinematicsParameters (int num_positions, std::optional< int > num_velocities=std::nullopt)
	Constructor. More...

void	AddLinearVelocityConstraint (const std::shared_ptr< solvers::LinearConstraint > constraint)
	Adds a linear velocity constraint. More...

void	ClearLinearVelocityConstraints ()
	Clears all linear velocity constraints. More...

Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	DifferentialInverseKinematicsParameters (const DifferentialInverseKinematicsParameters &)=default

DifferentialInverseKinematicsParameters &	operator= (const DifferentialInverseKinematicsParameters &)=default

	DifferentialInverseKinematicsParameters (DifferentialInverseKinematicsParameters &&)=default

DifferentialInverseKinematicsParameters &	operator= (DifferentialInverseKinematicsParameters &&)=default

Getters.
double	get_time_step () const

int	get_num_positions () const

int	get_num_velocities () const

const VectorX< double > &	get_nominal_joint_position () const

const MatrixX< double > &	get_joint_centering_gain () const

const Vector6< bool > &	get_end_effector_velocity_flag () const

const std::optional< std::pair< VectorX< double >, VectorX< double > > > &	get_joint_position_limits () const

const std::optional< std::pair< VectorX< double >, VectorX< double > > > &	get_joint_velocity_limits () const

const std::optional< std::pair< VectorX< double >, VectorX< double > > > &	get_joint_acceleration_limits () const

double	get_maximum_scaling_to_report_stuck () const

double	get_end_effector_angular_speed_limit () const

const std::optional< std::pair< Eigen::Vector3d, Eigen::Vector3d > > &	get_end_effector_translational_velocity_limits () const

const std::vector< std::shared_ptr< solvers::LinearConstraint > > &	get_linear_velocity_constraints () const

Setters.
void	set_time_step (double dt)
	Sets time step to `dt`. More...

void	set_nominal_joint_position (const Eigen::Ref< const VectorX< double >> &nominal_joint_position)
	Sets the nominal joint position. More...

void	set_end_effector_velocity_flag (const Vector6< bool > &flag_E)
	Sets the end effector flags in the body frame. More...

void	set_joint_centering_gain (const MatrixX< double > &K)
	Sets the joint centering gain, K, so that the joint centering command is attempting to achieve v_next = N⁺(q) * K * (q_nominal - q_current). More...

void	set_joint_position_limits (const std::pair< VectorX< double >, VectorX< double >> &q_bounds)
	Sets the joint position limits. More...

void	set_joint_velocity_limits (const std::pair< VectorX< double >, VectorX< double >> &v_bounds)
	Sets the joint velocity limits. More...

void	set_joint_acceleration_limits (const std::pair< VectorX< double >, VectorX< double >> &vd_bounds)
	Sets the joint acceleration limits. More...

void	set_maximum_scaling_to_report_stuck (double scaling)
	Sets the threshold for α below which the status returned is DifferentialInverseKinematicsStatus::kStuck. More...

void	set_end_effector_angular_speed_limit (double speed)
	When calling DoDifferentialInverseKinematics with a desired end-effector pose, this limits the magnitude of the angular velocity vector. More...

void	set_end_effector_translational_velocity_limits (const Eigen::Ref< const Eigen::Vector3d > &lower, const Eigen::Ref< const Eigen::Vector3d > &upper)
	When calling DoDifferentialInverseKinematics with a desired end-effector pose, this sets limits on the translational velocity. More...

Constructor & Destructor Documentation

◆ DifferentialInverseKinematicsParameters() [1/3]

DifferentialInverseKinematicsParameters ( const DifferentialInverseKinematicsParameters & )

default

◆ DifferentialInverseKinematicsParameters() [2/3]

DifferentialInverseKinematicsParameters ( DifferentialInverseKinematicsParameters && )

default

◆ DifferentialInverseKinematicsParameters() [3/3]

DifferentialInverseKinematicsParameters	(	int	num_positions,
		std::optional< int >	num_velocities = `std::nullopt`
	)

Constructor.

Initializes the nominal joint position to zeros of size num_positions. The time step is initialized to 1. The end effector flags are initialized to True. The joint centering gains are initialized to zero. All constraints are initialized to nullopt.

Parameters

num_positions	Number of generalized positions.
num_velocities	Number of generalized velocities (by default it will be set to num_positions).

Member Function Documentation

◆ AddLinearVelocityConstraint()

void AddLinearVelocityConstraint ( const std::shared_ptr< solvers::LinearConstraint > constraint )

Adds a linear velocity constraint.

Parameters

linear_velocity_constraint A linear constraint on joint velocities.

Exceptions

std::exception if constraint->num_vars != this->get_num_velocities().

◆ ClearLinearVelocityConstraints()

void ClearLinearVelocityConstraints ( )

Clears all linear velocity constraints.

◆ get_end_effector_angular_speed_limit()

double get_end_effector_angular_speed_limit ( ) const

◆ get_end_effector_translational_velocity_limits()

const std::optional<std::pair<Eigen::Vector3d, Eigen::Vector3d> >& get_end_effector_translational_velocity_limits ( ) const

◆ get_end_effector_velocity_flag()

const Vector6<bool>& get_end_effector_velocity_flag ( ) const

◆ get_joint_acceleration_limits()

const std::optional<std::pair<VectorX<double>, VectorX<double> > >& get_joint_acceleration_limits ( ) const

◆ get_joint_centering_gain()

const MatrixX<double>& get_joint_centering_gain ( ) const

◆ get_joint_position_limits()

const std::optional<std::pair<VectorX<double>, VectorX<double> > >& get_joint_position_limits ( ) const

◆ get_joint_velocity_limits()

const std::optional<std::pair<VectorX<double>, VectorX<double> > >& get_joint_velocity_limits ( ) const

◆ get_linear_velocity_constraints()

const std::vector<std::shared_ptr<solvers::LinearConstraint> >& get_linear_velocity_constraints ( ) const

◆ get_maximum_scaling_to_report_stuck()

double get_maximum_scaling_to_report_stuck ( ) const

◆ get_nominal_joint_position()

const VectorX<double>& get_nominal_joint_position ( ) const

◆ get_num_positions()

int get_num_positions ( ) const

◆ get_num_velocities()

int get_num_velocities ( ) const

◆ get_time_step()

double get_time_step ( ) const

◆ operator=() [1/2]

DifferentialInverseKinematicsParameters& operator= ( DifferentialInverseKinematicsParameters && )

default

◆ operator=() [2/2]

DifferentialInverseKinematicsParameters& operator= ( const DifferentialInverseKinematicsParameters & )

default

◆ set_end_effector_angular_speed_limit()

void set_end_effector_angular_speed_limit ( double speed )

When calling DoDifferentialInverseKinematics with a desired end-effector pose, this limits the magnitude of the angular velocity vector.

◆ set_end_effector_translational_velocity_limits()

void set_end_effector_translational_velocity_limits	(	const Eigen::Ref< const Eigen::Vector3d > &	lower,
		const Eigen::Ref< const Eigen::Vector3d > &	upper
	)

When calling DoDifferentialInverseKinematics with a desired end-effector pose, this sets limits on the translational velocity.

◆ set_end_effector_velocity_flag()

void set_end_effector_velocity_flag ( const Vector6< bool > & flag_E )

Sets the end effector flags in the body frame.

If a spatial velocity flag is set to false, it will not be included in the differential IK formulation.

◆ set_joint_acceleration_limits()

void set_joint_acceleration_limits ( const std::pair< VectorX< double >, VectorX< double >> & vd_bounds )

Sets the joint acceleration limits.

Parameters

q_bounds The first element is the lower bound, and the second is the upper bound.

Exceptions

std::exception if the first or second element of q_bounds has the wrong dimension or any element of the second element is smaller than its corresponding part in the first element.

◆ set_joint_centering_gain()

void set_joint_centering_gain ( const MatrixX< double > & K )

Sets the joint centering gain, K, so that the joint centering command is attempting to achieve v_next = N⁺(q) * K * (q_nominal - q_current).

Precondition: K must be num_positions x num_positions.

◆ set_joint_position_limits()

void set_joint_position_limits ( const std::pair< VectorX< double >, VectorX< double >> & q_bounds )

Sets the joint position limits.

Parameters

q_bounds The first element is the lower bound, and the second is the upper bound.

Exceptions

std::exception if the first or second element of q_bounds has the wrong dimension or any element of the second element is smaller than its corresponding part in the first element.

◆ set_joint_velocity_limits()

void set_joint_velocity_limits ( const std::pair< VectorX< double >, VectorX< double >> & v_bounds )

Sets the joint velocity limits.

Parameters

q_bounds The first element is the lower bound, and the second is the upper bound.

Exceptions

std::exception if the first or second element of q_bounds has the wrong dimension or any element of the second element is smaller than its corresponding part in the first element.

◆ set_maximum_scaling_to_report_stuck()

void set_maximum_scaling_to_report_stuck ( double scaling )

Sets the threshold for α below which the status returned is DifferentialInverseKinematicsStatus::kStuck.

α is the scaling of the commanded spatial velocity, so when α is small, it means that the actual spatial velocity magnitude will be small proportional to the commanded.
Default: 0.01.

◆ set_nominal_joint_position()

void set_nominal_joint_position ( const Eigen::Ref< const VectorX< double >> & nominal_joint_position )

Sets the nominal joint position.

Exceptions

std::exception if nominal_joint_position's dimension differs.

◆ set_time_step()

void set_time_step ( double dt )

Sets time step to dt.

Exceptions

std::exception if dt <= 0.

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

drake/multibody/inverse_kinematics/differential_inverse_kinematics.h

Detailed Description

Public Member Functions

Constructor & Destructor Documentation

◆ DifferentialInverseKinematicsParameters() [1/3]

◆ DifferentialInverseKinematicsParameters() [2/3]

◆ DifferentialInverseKinematicsParameters() [3/3]

Member Function Documentation

◆ AddLinearVelocityConstraint()

◆ ClearLinearVelocityConstraints()

◆ get_end_effector_angular_speed_limit()

◆ get_end_effector_translational_velocity_limits()

◆ get_end_effector_velocity_flag()

◆ get_joint_acceleration_limits()

◆ get_joint_centering_gain()

◆ get_joint_position_limits()

◆ get_joint_velocity_limits()

◆ get_linear_velocity_constraints()

◆ get_maximum_scaling_to_report_stuck()

◆ get_nominal_joint_position()

◆ get_num_positions()

◆ get_num_velocities()

◆ get_time_step()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ set_end_effector_angular_speed_limit()

◆ set_end_effector_translational_velocity_limits()

◆ set_end_effector_velocity_flag()

◆ set_joint_acceleration_limits()

◆ set_joint_centering_gain()

◆ set_joint_position_limits()

◆ set_joint_velocity_limits()

◆ set_maximum_scaling_to_report_stuck()

◆ set_nominal_joint_position()

◆ set_time_step()