GradientMethod is a base class for different ways of computing the gradient of an InverseKinematics module. More...

#include <InverseKinematics.hpp>

Inheritance diagram for dart::dynamics::InverseKinematics::GradientMethod:

Collaboration diagram for dart::dynamics::InverseKinematics::GradientMethod:

Classes
struct	Properties

Public Member Functions
	GradientMethod (InverseKinematics *_ik, const std::string &_methodName, const Properties &_properties)
	Constructor.

virtual	~GradientMethod ()=default
	Virtual destructor.

virtual std::unique_ptr< GradientMethod >	clone (InverseKinematics *_newIK) const =0
	Enable this GradientMethod to be cloned to a new IK module.

virtual void	computeGradient (const Eigen::Vector6d &_error, Eigen::VectorXd &_grad)=0
	Override this function with your implementation of the gradient computation. More...

void	evalGradient (const Eigen::VectorXd &_q, Eigen::Map< Eigen::VectorXd > _grad)
	This function is used to handle caching the gradient vector and interfacing with the solver. More...

const std::string &	getMethodName () const
	Get the name of this GradientMethod.

void	clampGradient (Eigen::VectorXd &_grad) const
	Clamp the gradient based on the clamp settings of this GradientMethod.

void	setComponentWiseClamp (double _clamp=DefaultIKGradientComponentClamp)
	Set the component-wise clamp for this GradientMethod. More...

double	getComponentWiseClamp () const
	Get the component-wise clamp for this GradientMethod.

void	applyWeights (Eigen::VectorXd &_grad) const
	Apply weights to the gradient based on the weight settings of this GradientMethod. More...

void	setComponentWeights (const Eigen::VectorXd &_weights)
	Set the weights that will be applied to each component of the gradient. More...

const Eigen::VectorXd &	getComponentWeights () const
	Get the weights of this GradientMethod.

void	convertJacobianMethodOutputToGradient (Eigen::VectorXd &grad, const std::vector< std::size_t > &dofs)
	Convert the gradient that gets generated by Jacobian methods into a gradient that can be used by a GradientDescentSolver. More...

Properties	getGradientMethodProperties () const
	Get the Properties of this GradientMethod.

void	clearCache ()
	Clear the cache to force the gradient to be recomputed. More...

InverseKinematics *	getIK ()
	Returns the IK module that this GradientMethod belongs to.

const InverseKinematics *	getIK () const
	Returns the IK module that this GradientMethod belongs to.

Public Member Functions inherited from dart::common::Subject
virtual	~Subject ()
	Destructor will notify all Observers that it is destructing.

Protected Attributes
common::sub_ptr< InverseKinematics >	mIK
	The IK module that this GradientMethod belongs to.

std::string	mMethodName
	The name of this method.

Eigen::VectorXd	mLastPositions
	The last positions that was passed to this GradientMethod.

Eigen::VectorXd	mLastGradient
	The last gradient that was computed by this GradientMethod.

Properties	mGradientP
	Properties for this GradientMethod.

Protected Attributes inherited from dart::common::Subject
std::set< Observer * >	mObservers
	List of current Observers.

Additional Inherited Members
Protected Member Functions inherited from dart::common::Subject
void	sendDestructionNotification () const
	Send a destruction notification to all Observers. More...

void	addObserver (Observer *_observer) const
	Add an Observer to the list of Observers.

void	removeObserver (Observer *_observer) const
	Remove an Observer from the list of Observers.

Detailed Description

GradientMethod is a base class for different ways of computing the gradient of an InverseKinematics module.

Member Function Documentation

◆ applyWeights()

void dart::dynamics::InverseKinematics::GradientMethod::applyWeights ( Eigen::VectorXd & _grad ) const

Apply weights to the gradient based on the weight settings of this GradientMethod.

◆ clearCache()

void dart::dynamics::InverseKinematics::GradientMethod::clearCache ( )

Clear the cache to force the gradient to be recomputed.

It should generally not be necessary to call this function.

◆ computeGradient()

virtual void dart::dynamics::InverseKinematics::GradientMethod::computeGradient	(	const Eigen::Vector6d &	_error,
		Eigen::VectorXd &	_grad
	)

pure virtual

Override this function with your implementation of the gradient computation.

The direction that this gradient points in should make the error worse if applied to the joint positions, because the Problem is configured as a gradient descent error minimization Problem.

The error vector that is passed in will be determined by the IK module's ErrorMethod. The expectation is that the first three components of the vector correspond to orientation error (in an angle-axis format) while the last three components correspond to translational error.

When implementing this function, you should assume that the Skeleton's current joint positions corresponds to the positions that you must use to compute the error. This function will only get called when an update is needed.

Implemented in dart::dynamics::InverseKinematics::Analytical, dart::dynamics::InverseKinematics::JacobianTranspose, and dart::dynamics::InverseKinematics::JacobianDLS.

◆ convertJacobianMethodOutputToGradient()

void dart::dynamics::InverseKinematics::GradientMethod::convertJacobianMethodOutputToGradient	(	Eigen::VectorXd &	grad,
		const std::vector< std::size_t > &	dofs
	)

Convert the gradient that gets generated by Jacobian methods into a gradient that can be used by a GradientDescentSolver.

Not all Joint types can be integrated using standard addition (e.g. FreeJoint and BallJoint), therefore Jacobian-based differential methods will tend to generate gradients that cannot be correctly used by a simple addition-based GradientDescentSolver. Running your gradient through this function before returning it will make the gradient suitable for a standard solver.

◆ evalGradient()

void dart::dynamics::InverseKinematics::GradientMethod::evalGradient	(	const Eigen::VectorXd &	_q,
		Eigen::Map< Eigen::VectorXd >	_grad
	)

This function is used to handle caching the gradient vector and interfacing with the solver.

◆ setComponentWeights()

void dart::dynamics::InverseKinematics::GradientMethod::setComponentWeights ( const Eigen::VectorXd & _weights )

Set the weights that will be applied to each component of the gradient.

If the number of components in _weights is smaller than the number of components in the gradient, then a weight of 1.0 will be applied to all components that are out of the range of _weights. Passing in an empty vector for _weights will effectively make all the gradient components unweighted.

◆ setComponentWiseClamp()

void dart::dynamics::InverseKinematics::GradientMethod::setComponentWiseClamp ( double _clamp = DefaultIKGradientComponentClamp )

Set the component-wise clamp for this GradientMethod.

Each component of the gradient will be individually clamped to this size.

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

dart/dynamics/InverseKinematics.hpp
dart/dynamics/InverseKinematics.cpp

Classes

Public Member Functions

Protected Attributes

Additional Inherited Members