This class gives the abstract definition of a feature. More...

#include <sot/core/feature-abstract.hh>

Inheritance diagram for dynamicgraph::sot::FeatureAbstract:

[legend]

Public Member Functions
virtual const std::string &	getClassName (void) const
	Returns the name class. More...

void	featureRegistration (void)
	Register the feature in the stack of tasks. More...

void	initCommands (void)

	FeatureAbstract (const std::string &name)
	Default constructor: the name of the class should be given. More...

virtual	~FeatureAbstract (void)
	Default destructor. More...

Methods returning the dimension of the feature.
virtual unsigned int &	getDimension (unsigned int &res, int time)=0
	Verbose method. More...

unsigned int	getDimension (int time)
	Short method. More...

unsigned int	getDimension (void) const
	Shortest method. More...

Methods to control internal computation.
The main idea is that some feature may have a lower frequency than the internal control loop. In this case, the methods for computation are called only when needed.
virtual dynamicgraph::Vector &	computeError (dynamicgraph::Vector &res, int time)=0
	Compute the error between the desired feature and the current value of the feature measured or deduced from the robot state. More...

virtual dynamicgraph::Matrix &	computeJacobian (dynamicgraph::Matrix &res, int time)=0
	Compute the Jacobian of the error according the robot state. More...

virtual dynamicgraph::Vector &	computeErrorDot (dynamicgraph::Vector &res, int time)

Reference
virtual void	setReference (FeatureAbstract *sdes)=0

virtual void	unsetReference (void)

virtual const FeatureAbstract *	getReferenceAbstract (void) const =0

virtual FeatureAbstract *	getReferenceAbstract (void)=0

virtual bool	isReferenceSet (void) const

virtual void	addDependenciesFromReference (void)=0

virtual void	removeDependenciesFromReference (void)=0

void	setReferenceByName (const std::string &name)

std::string	getReferenceByName (void) const

Public Attributes
Input signals:
SignalPtr< Flags, int >	selectionSIN
	This vector specifies which dimension are used to perform the computation. For instance let us assume that the feature is a 3D point. If only the Y-axis should be used for computing error, activation and Jacobian, then the vector to specify is \( [ 0 1 0] \). More...

SignalPtr< dynamicgraph::Vector, int >	errordotSIN
	Derivative of the reference value. More...

Static Public Attributes
static const std::string	CLASS_NAME
	Store the name of the class. More...

Output signals:
SignalTimeDependent< dynamicgraph::Vector, int >	errorSOUT
	This signal returns the error between the desired value and the current value : \( E(t) = {\bf s}(t) - {\bf s}^*(t)\). More...

SignalTimeDependent< dynamicgraph::Vector, int >	errordotSOUT
	Derivative of the error with respect to time: \( \frac{\partial e}{\partial t} = - \frac{d{\bf s}^*}{dt} \). More...

SignalTimeDependent< dynamicgraph::Matrix, int >	jacobianSOUT
	Jacobian of the error wrt the robot state: \( J = \frac{\partial {\bf s}}{\partial {\bf q}}\). More...

SignalTimeDependent< unsigned int, int >	dimensionSOUT
	Returns the dimension of the feature as an output signal. More...

virtual std::ostream &	writeGraph (std::ostream &os) const
	This method write a graph description on the file named FileName. More...

virtual SignalTimeDependent< dynamicgraph::Vector, int > &	getErrorDot ()

Detailed Description

This class gives the abstract definition of a feature.

par_features_definition Definition: In short, a feature is a data evolving according to time. It is defined by a vector \({\bf s}({\bf q}) \in \mathbb{R}^n \) where \( {\bf q} \) is a robot configuration, which depends on the time \( t \). By default a feature has a desired \({\bf s}^*(t) \). \({\bf s}^*\) is provided by another feature of the same type called reference. The feature is in charge of collecting its own current state. A feature is supposed to compute an error between its current state and the desired one: \( E(t) = e({\bf q}(t), t) = {\bf s}({\bf q}(t)) \ominus {\bf s}^*(t) \). Here, \( \ominus \) is the difference operator of Lie group in which \( {\bf s} \) and \( {\bf s}^* \) are. The documentation below assumes the Lie group is a vector space and \(\ominus\) is the usual difference operator.

A feature computes:

the Jacobian according to the robot state vector \( J = \frac{\partial e}{\partial {\bf q}} = \frac{\partial{\bf s}}{\partial {\bf q}}\).
the partial derivative of the error \( e \): \( \frac{\partial e}{\partial t} = - \frac{d{\bf s}^*}{dt}\).

The task is in general computed from the value of the feature at the current instant \(E(t) = e({\bf q},t)\). The derivative of \( E \) is:

\[ \frac{dE}{dt} = J({\bf q}) \dot{q} + \frac{\partial e}{\partial t} \]

Feature diagram: Feature types derive from

FeatureAbstract. Each feature has a reference of the same type and compute an error by comparing errorSIN signals from itself and from the reference."

Constructor & Destructor Documentation

◆ FeatureAbstract()

dynamicgraph::sot::FeatureAbstract::FeatureAbstract ( const std::string & name )

Default constructor: the name of the class should be given.

◆ ~FeatureAbstract()

virtual dynamicgraph::sot::FeatureAbstract::~FeatureAbstract ( void )

inlinevirtual

Default destructor.

Member Function Documentation

◆ addDependenciesFromReference()

virtual void dynamicgraph::sot::FeatureAbstract::addDependenciesFromReference ( void )

pure virtual

◆ computeError()

virtual dynamicgraph::Vector& dynamicgraph::sot::FeatureAbstract::computeError	(	dynamicgraph::Vector &	res,
		int	time
	)

pure virtual

Compute the error between the desired feature and the current value of the feature measured or deduced from the robot state.

[out] res: The error will be set into res.

[in] time: The time at which the error is computed.

Returns: The vector res with the appropriate value.

Implemented in dynamicgraph::sot::FeaturePosture, dynamicgraph::sot::FeatureVisualPoint, dynamicgraph::sot::FeatureVector3, dynamicgraph::sot::FeaturePose< representation >, dynamicgraph::sot::FeaturePoint6d, dynamicgraph::sot::FeaturePoint6dRelative, dynamicgraph::sot::FeatureLineDistance, dynamicgraph::sot::FeatureJointLimits, dynamicgraph::sot::FeatureGeneric, and dynamicgraph::sot::Feature1D.

◆ computeErrorDot()

virtual dynamicgraph::Vector& dynamicgraph::sot::FeatureAbstract::computeErrorDot	(	dynamicgraph::Vector &	res,
		int	time
	)

virtual

Callback for signal errordotSOUT

Copy components of the input signal errordotSIN defined by selection flag selectionSIN.

Reimplemented in dynamicgraph::sot::FeaturePosture, dynamicgraph::sot::FeaturePose< representation >, and dynamicgraph::sot::FeaturePoint6dRelative.

◆ computeJacobian()

virtual dynamicgraph::Matrix& dynamicgraph::sot::FeatureAbstract::computeJacobian	(	dynamicgraph::Matrix &	res,
		int	time
	)

pure virtual

Compute the Jacobian of the error according the robot state.

[out] res: The matrix in which the error will be written.

Returns: The matrix res with the appropriate values.

Implemented in dynamicgraph::sot::FeaturePosture, dynamicgraph::sot::FeatureVisualPoint, dynamicgraph::sot::FeatureVector3, dynamicgraph::sot::FeaturePose< representation >, dynamicgraph::sot::FeaturePoint6d, dynamicgraph::sot::FeaturePoint6dRelative, dynamicgraph::sot::FeatureLineDistance, dynamicgraph::sot::FeatureJointLimits, dynamicgraph::sot::FeatureGeneric, and dynamicgraph::sot::Feature1D.

◆ featureRegistration()

void dynamicgraph::sot::FeatureAbstract::featureRegistration ( void )

Register the feature in the stack of tasks.

◆ getClassName()

virtual const std::string& dynamicgraph::sot::FeatureAbstract::getClassName ( void ) const

inlinevirtual

Returns the name class.

Reimplemented in dynamicgraph::sot::FeatureVisualPoint, dynamicgraph::sot::FeatureVector3, dynamicgraph::sot::FeatureTask, dynamicgraph::sot::FeaturePose< representation >, dynamicgraph::sot::FeaturePoint6d, dynamicgraph::sot::FeaturePoint6dRelative, dynamicgraph::sot::FeatureLineDistance, dynamicgraph::sot::FeatureJointLimits, dynamicgraph::sot::FeatureGeneric, and dynamicgraph::sot::Feature1D.

◆ getDimension() [1/3]

unsigned int dynamicgraph::sot::FeatureAbstract::getDimension ( int time )

inline

Short method.

time: The time at which the feature should be considered.

Returns: Dimension of the feature.

Note: Be careful with features changing their dimension according to time.

◆ getDimension() [2/3]

virtual unsigned int& dynamicgraph::sot::FeatureAbstract::getDimension	(	unsigned int &	res,
		int	time
	)

pure virtual

Verbose method.

res: The integer in which the dimension will be return.

time: The time at which the feature should be considered.

Returns: Dimension of the feature.

Note: Be careful with features changing their dimension according to time.

Implemented in dynamicgraph::sot::FeaturePosture, dynamicgraph::sot::FeatureVisualPoint, dynamicgraph::sot::FeatureVector3, dynamicgraph::sot::FeaturePose< representation >, dynamicgraph::sot::FeaturePoint6d, dynamicgraph::sot::FeatureLineDistance, dynamicgraph::sot::FeatureJointLimits, dynamicgraph::sot::FeatureGeneric, and dynamicgraph::sot::Feature1D.

◆ getDimension() [3/3]

unsigned int dynamicgraph::sot::FeatureAbstract::getDimension ( void ) const

inline

Shortest method.

Returns: Dimension of the feature.

Note: The feature is not changing its dimension according to time.

◆ getErrorDot()

virtual SignalTimeDependent<dynamicgraph::Vector, int>& dynamicgraph::sot::FeatureAbstract::getErrorDot ( )

inlinevirtual

◆ getReferenceAbstract() [1/2]

virtual const FeatureAbstract* dynamicgraph::sot::FeatureAbstract::getReferenceAbstract ( void ) const

pure virtual

◆ getReferenceAbstract() [2/2]

virtual FeatureAbstract* dynamicgraph::sot::FeatureAbstract::getReferenceAbstract ( void )

pure virtual

◆ getReferenceByName()

std::string dynamicgraph::sot::FeatureAbstract::getReferenceByName ( void ) const

◆ initCommands()

void dynamicgraph::sot::FeatureAbstract::initCommands ( void )

◆ isReferenceSet()

virtual bool dynamicgraph::sot::FeatureAbstract::isReferenceSet ( void ) const

inlinevirtual

◆ removeDependenciesFromReference()

virtual void dynamicgraph::sot::FeatureAbstract::removeDependenciesFromReference ( void )

pure virtual

◆ setReference()

virtual void dynamicgraph::sot::FeatureAbstract::setReference ( FeatureAbstract * sdes )

pure virtual

◆ setReferenceByName()

void dynamicgraph::sot::FeatureAbstract::setReferenceByName ( const std::string & name )

◆ unsetReference()

virtual void dynamicgraph::sot::FeatureAbstract::unsetReference ( void )

inlinevirtual

◆ writeGraph()

virtual std::ostream& dynamicgraph::sot::FeatureAbstract::writeGraph ( std::ostream & os ) const

virtual

This method write a graph description on the file named FileName.

Member Data Documentation

◆ CLASS_NAME

const std::string dynamicgraph::sot::FeatureAbstract::CLASS_NAME

static

Store the name of the class.

◆ dimensionSOUT

SignalTimeDependent<unsigned int, int> dynamicgraph::sot::FeatureAbstract::dimensionSOUT

Returns the dimension of the feature as an output signal.

◆ errordotSIN

SignalPtr<dynamicgraph::Vector, int> dynamicgraph::sot::FeatureAbstract::errordotSIN

Derivative of the reference value.

◆ errordotSOUT

SignalTimeDependent<dynamicgraph::Vector, int> dynamicgraph::sot::FeatureAbstract::errordotSOUT

Derivative of the error with respect to time: \( \frac{\partial e}{\partial t} = - \frac{d{\bf s}^*}{dt} \).

◆ errorSOUT

SignalTimeDependent<dynamicgraph::Vector, int> dynamicgraph::sot::FeatureAbstract::errorSOUT

This signal returns the error between the desired value and the current value : \( E(t) = {\bf s}(t) - {\bf s}^*(t)\).

◆ jacobianSOUT

SignalTimeDependent<dynamicgraph::Matrix, int> dynamicgraph::sot::FeatureAbstract::jacobianSOUT

Jacobian of the error wrt the robot state: \( J = \frac{\partial {\bf s}}{\partial {\bf q}}\).

◆ selectionSIN

SignalPtr<Flags, int> dynamicgraph::sot::FeatureAbstract::selectionSIN

This vector specifies which dimension are used to perform the computation. For instance let us assume that the feature is a 3D point. If only the Y-axis should be used for computing error, activation and Jacobian, then the vector to specify is \( [ 0 1 0] \).

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

include/sot/core/feature-abstract.hh

Public Member Functions

Public Attributes

Static Public Attributes

Output signals:

Detailed Description

Constructor & Destructor Documentation

◆ FeatureAbstract()

◆ ~FeatureAbstract()

Member Function Documentation

◆ addDependenciesFromReference()

◆ computeError()

◆ computeErrorDot()

◆ computeJacobian()

◆ featureRegistration()

◆ getClassName()

◆ getDimension() [1/3]

◆ getDimension() [2/3]

◆ getDimension() [3/3]

◆ getErrorDot()

◆ getReferenceAbstract() [1/2]

◆ getReferenceAbstract() [2/2]

◆ getReferenceByName()

◆ initCommands()

◆ isReferenceSet()

◆ removeDependenciesFromReference()

◆ setReference()

◆ setReferenceByName()

◆ unsetReference()

◆ writeGraph()

Member Data Documentation

◆ CLASS_NAME

◆ dimensionSOUT

◆ errordotSIN

◆ errordotSOUT

◆ errorSOUT

◆ jacobianSOUT

◆ selectionSIN