The InverseKinematics class provides a convenient way of setting up an IK optimization problem. More...

#include <InverseKinematics.hpp>

Inheritance diagram for dart::dynamics::InverseKinematics:

Classes
class	Analytical
	Analytical is a base class that should be inherited by methods that are made to solve the IK analytically instead of iteratively. More...

class	Constraint
	The InverseKinematics::Constraint Function is simply meant to be used to merge the ErrorMethod and GradientMethod that are being held by an InverseKinematics module. More...

class	ErrorMethod
	ErrorMethod is a base class for different ways of computing the error of an InverseKinematics module. More...

class	Function
	This class should be inherited by optimizer::Function classes that have a dependency on the InverseKinematics module that they belong to. More...

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

class	JacobianDLS
	JacobianDLS refers to the Damped Least Squares Jacobian Pseudoinverse (specifically, Moore-Penrose Pseudoinverse). More...

class	JacobianTranspose
	JacobianTranspose will simply apply the transpose of the Jacobian to the error vector in order to compute the gradient. More...

class	Objective
	The InverseKinematics::Objective Function is simply used to merge the objective and null space objective functions that are being held by an InverseKinematics module. More...

class	TaskSpaceRegion
	The TaskSpaceRegion is a nicely generalized method for computing the error of an IK Problem. More...

Public Member Functions
	InverseKinematics (const InverseKinematics &)=delete
	Copying is not allowed. More...

InverseKinematics &	operator= (const InverseKinematics &)=delete
	Assignment is not allowed. More...

virtual	~InverseKinematics ()
	Virtual destructor. More...

bool	solve (bool applySolution=true)
	Solve the IK Problem. More...

bool	solve (Eigen::VectorXd &positions, bool applySolution=true)
	Same as solve(bool), but the positions vector will be filled with the solved positions. More...

bool	findSolution (Eigen::VectorXd &positions)
	Finds a solution of the IK problem without applying the solution. More...

bool	solveAndApply (bool allowIncompleteResult=true)
	Identical to findSolution(), but this function applies the solution when the solver successfully found a solution or `allowIncompleteResult` is set to true. More...

bool	solveAndApply (Eigen::VectorXd &positions, bool allowIncompleteResult=true)
	Identical to solveAndApply(bool), but `position` will be filled with the solved positions. More...

InverseKinematicsPtr	clone (JacobianNode *_newNode) const
	Clone this IK module, but targeted at a new Node. More...

void	setActive (bool _active=true)
	If this IK module is set to active, then it will be utilized by any HierarchicalIK that has it in its list. More...

void	setInactive ()
	Equivalent to setActive(false) More...

bool	isActive () const
	Returns true if this IK module is allowed to be active in a HierarchicalIK. More...

void	setHierarchyLevel (std::size_t _level)
	Set the hierarchy level of this module. More...

std::size_t	getHierarchyLevel () const
	Get the hierarchy level of this modle. More...

void	useChain ()
	When solving the IK for this module's Node, use the longest available dynamics::Chain that goes from this module's Node towards the root of the Skeleton. More...

void	useWholeBody ()
	Use all relevant joints on the Skeleton to solve the IK. More...

template<class DegreeOfFreedomT >
void	setDofs (const std::vector< DegreeOfFreedomT * > &_dofs)
	Explicitly set which degrees of freedom should be used to solve the IK for this module. More...

void	setDofs (const std::vector< std::size_t > &_dofs)
	Explicitly set which degrees of freedom should be used to solve the IK for this module. More...

const std::vector< std::size_t > &	getDofs () const
	Get the indices of the DOFs that this IK module will use when solving. More...

const std::vector< int > &	getDofMap () const
	When a Jacobian is computed for a JacobianNode, it will include a column for every DegreeOfFreedom that the node depends on. More...

void	setObjective (const std::shared_ptr< optimizer::Function > &_objective)
	Set an objective function that should be minimized while satisfying the inverse kinematics constraint. More...

const std::shared_ptr< optimizer::Function > &	getObjective ()
	Get the objective function for this IK module. More...

std::shared_ptr< const optimizer::Function >	getObjective () const
	Get the objective function for this IK module. More...

void	setNullSpaceObjective (const std::shared_ptr< optimizer::Function > &_nsObjective)
	Set an objective function that should be minimized within the null space of the inverse kinematics constraint. More...

const std::shared_ptr< optimizer::Function > &	getNullSpaceObjective ()
	Get the null space objective for this IK module. More...

std::shared_ptr< const optimizer::Function >	getNullSpaceObjective () const
	Get the null space objective for this IK module. More...

bool	hasNullSpaceObjective () const
	Returns false if the null space objective does nothing. More...

template<class IKErrorMethod , typename... Args>
IKErrorMethod &	setErrorMethod (Args &&... args)
	Set the ErrorMethod for this IK module. More...

ErrorMethod &	getErrorMethod ()
	Get the ErrorMethod for this IK module. More...

const ErrorMethod &	getErrorMethod () const
	Get the ErrorMethod for this IK module. More...

template<class IKGradientMethod , typename... Args>
IKGradientMethod &	setGradientMethod (Args &&... args)
	Set the GradientMethod for this IK module. More...

GradientMethod &	getGradientMethod ()
	Get the GradientMethod for this IK module. More...

const GradientMethod &	getGradientMethod () const
	Get the GradientMethod for this IK module. More...

Analytical *	getAnalytical ()
	Get the Analytical IK method for this module, if one is available. More...

const Analytical *	getAnalytical () const
	Get the Analytical IK method for this module, if one is available. More...

const std::shared_ptr< optimizer::Problem > &	getProblem ()
	Get the Problem that is being maintained by this IK module. More...

std::shared_ptr< const optimizer::Problem >	getProblem () const
	Get the Problem that is being maintained by this IK module. More...

void	resetProblem (bool _clearSeeds=false)
	Reset the Problem that is being maintained by this IK module. More...

void	setSolver (const std::shared_ptr< optimizer::Solver > &_newSolver)
	Set the Solver that should be used by this IK module, and set it up with the Problem that is configured by this IK module. More...

const std::shared_ptr< optimizer::Solver > &	getSolver ()
	Get the Solver that is being used by this IK module. More...

std::shared_ptr< const optimizer::Solver >	getSolver () const
	Get the Solver that is being used by this IK module. More...

void	setOffset (const Eigen::Vector3d &_offset=Eigen::Vector3d::Zero())
	Inverse kinematics can be performed on any point within the body frame. More...

const Eigen::Vector3d &	getOffset () const
	Get the offset from the origin of the body frame that will be used when performing inverse kinematics. More...

bool	hasOffset () const
	This returns false if the offset for the inverse kinematics is a zero vector. More...

void	setTarget (std::shared_ptr< SimpleFrame > _newTarget)
	Set the target for this IK module. More...

std::shared_ptr< SimpleFrame >	getTarget ()
	Get the target that is being used by this IK module. More...

std::shared_ptr< const SimpleFrame >	getTarget () const
	Get the target that is being used by this IK module. More...

JacobianNode *	getNode ()
	Get the JacobianNode that this IK module operates on. More...

const JacobianNode *	getNode () const
	Get the JacobianNode that this IK module operates on. More...

JacobianNode *	getAffiliation ()
	This is the same as getNode(). More...

const JacobianNode *	getAffiliation () const
	This is the same as getNode(). More...

const math::Jacobian &	computeJacobian () const
	Compute the Jacobian for this IK module's node, using the Skeleton's current joint positions and the DOFs that have been assigned to the module. More...

Eigen::VectorXd	getPositions () const
	Get the current joint positions of the Skeleton. More...

void	setPositions (const Eigen::VectorXd &_q)
	Set the current joint positions of the Skeleton. More...

void	clearCaches ()
	Clear the caches of this IK module. More...

Static Public Member Functions
static InverseKinematicsPtr	create (JacobianNode *_node)
	Create an InverseKinematics module for a specified node. More...

Protected Member Functions
	InverseKinematics (JacobianNode *_node)
	Constructor that accepts a JacobianNode. More...

void	initialize ()
	Gets called during construction. More...

void	resetTargetConnection ()
	Reset the signal connection for this IK module's target. More...

void	resetNodeConnection ()
	Reset the signal connection for this IK module's Node. More...

void	sendDestructionNotification () const
	Send a destruction notification to all Observers. More...

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

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

Protected Attributes
common::Connection	mTargetConnection
	Connection to the target update. More...

common::Connection	mNodeConnection
	Connection to the node update. More...

bool	mActive
	True if this IK module should be active in its IK hierarcy. More...

std::size_t	mHierarchyLevel
	Hierarchy level for this IK module. More...

std::vector< std::size_t >	mDofs
	A list of the DegreeOfFreedom Skeleton indices that will be used by this IK module. More...

std::vector< int >	mDofMap
	Map for the DOFs that are to be used by this IK module. More...

std::shared_ptr< optimizer::Function >	mObjective
	Objective for the IK module. More...

std::shared_ptr< optimizer::Function >	mNullSpaceObjective
	Null space objective for the IK module. More...

std::unique_ptr< ErrorMethod >	mErrorMethod
	The method that this IK module will use to compute errors. More...

std::unique_ptr< GradientMethod >	mGradientMethod
	The method that this IK module will use to compute gradients. More...

Analytical *	mAnalytical
	If mGradientMethod is an Analytical extension, then this will have the same value is mGradientMethod. More...

std::shared_ptr< optimizer::Problem >	mProblem
	The Problem that will be maintained by this IK module. More...

std::shared_ptr< optimizer::Solver >	mSolver
	The solver that this IK module will use for iterative methods. More...

Eigen::Vector3d	mOffset
	The offset that this IK module should use when computing IK. More...

bool	mHasOffset
	True if the offset is non-zero. More...

std::shared_ptr< SimpleFrame >	mTarget
	Target that this IK module should use. More...

sub_ptr< JacobianNode >	mNode
	JacobianNode that this IK module is associated with. More...

math::Jacobian	mJacobian
	Jacobian cache for the IK module. More...

std::set< Observer * >	mObservers
	List of current Observers. More...

Friends
class	Objective

class	Constraint

Detailed Description

The InverseKinematics class provides a convenient way of setting up an IK optimization problem.

It generates constraint functions based on the specified InverseKinematics::ErrorMethod and InverseKinematics::GradientMethod. The optimization problem is then solved by any classes derived from optimizer::Solver class. The default solver is optimizer::GradientDescentSolver.

It also provides a convenient way of specifying a configuration space objective and a null space objective. It is also possible to fully customize the optimizer::Problem that the module creates, and the IK module can be safely cloned over to another JacobianNode, as long as every optimizer::Function that depends on the JacobianNode inherits the InverseKinematics::Function class and correctly overloads the clone function

Constructor & Destructor Documentation

◆ InverseKinematics() [1/2]

dart::dynamics::InverseKinematics::InverseKinematics ( const InverseKinematics & )

delete

Copying is not allowed.

◆ ~InverseKinematics()

dart::dynamics::InverseKinematics::~InverseKinematics ( )

virtual

Virtual destructor.

◆ InverseKinematics() [2/2]

dart::dynamics::InverseKinematics::InverseKinematics ( JacobianNode * _node )

protected

Constructor that accepts a JacobianNode.

Member Function Documentation

◆ addObserver()

void dart::common::Subject::addObserver ( Observer * _observer ) const

protectedinherited

Add an Observer to the list of Observers.

◆ clearCaches()

void dart::dynamics::InverseKinematics::clearCaches ( )

Clear the caches of this IK module.

It should generally not be necessary to call this function. However, if you have some non-standard external dependency for your error and/or gradient method computations, then you will need to tie this function to something that tracks changes in that dependency.

◆ clone()

InverseKinematicsPtr dart::dynamics::InverseKinematics::clone ( JacobianNode * _newNode ) const

Clone this IK module, but targeted at a new Node.

Any Functions in the Problem that inherit InverseKinematics::Function will be adapted to the new IK module. Any generic optimizer::Function will just be copied over by pointer instead of being cloned.

◆ computeJacobian()

const math::Jacobian & dart::dynamics::InverseKinematics::computeJacobian ( ) const

Compute the Jacobian for this IK module's node, using the Skeleton's current joint positions and the DOFs that have been assigned to the module.

◆ create()

InverseKinematicsPtr dart::dynamics::InverseKinematics::create ( JacobianNode * _node )

static

Create an InverseKinematics module for a specified node.

◆ findSolution()

bool dart::dynamics::InverseKinematics::findSolution ( Eigen::VectorXd & positions )

Finds a solution of the IK problem without applying the solution.

The initial guess for the IK optimization problem is the current joint positions of the target system. If the iterative solver fails to find a successive solution, it attempts more to solve the problem with other seed configurations or random configurations if enough seed is not provided.

Here is the pseudocode as described above:

attempts <- 0
initial_guess <- current_joint_positions
while attempts <= max_attempts:
  result <- solve(initial_guess)
  if result = success:
    return
  else:
    attempts <- attempts + 1
    if attempts <= num_seed:
      initial_guess <- seed[attempts - 1]
    else:
      initial_guess <- random_configuration  // within the bounds

By default, the max_attempts is 1, but this can be changed by calling InverseKinematics::getSolver() and casting the SolverPtr to an optimizer::GradientDescentSolver (unless you have changed the Solver type) and then calling GradientDescentSolver::setMaxAttempts(std::size_t).

By default, the list of seeds is empty, but they can be added by calling InverseKinematics::getProblem() and then using Problem::addSeed(Eigen::VectorXd).

Calling this function will automatically call Position::setLowerBounds(~) and Position::setUpperBounds(~) with the lower/upper position bounds of the corresponding Degrees Of Freedom. Problem::setDimension(~) will be taken care of automatically, and Problem::setInitialGuess(~) will be called with the current positions of the Degrees Of Freedom.

Parameters

[out] positions The solution of the IK problem. If the solver failed to find a solution then it will still set the position with the best guess. For example, iterative solvers will fill positions with the last result of the iterations.

Returns: True if a solution is successfully found.

See also: solveAndApply()

◆ getAffiliation() [1/2]

JacobianNode * dart::dynamics::InverseKinematics::getAffiliation ( )

This is the same as getNode().

It is used by the InverseKinematicsPtr to provide a common interface for the various IK smart pointer types.

◆ getAffiliation() [2/2]

const JacobianNode * dart::dynamics::InverseKinematics::getAffiliation ( ) const

This is the same as getNode().

It is used by the InverseKinematicsPtr to provide a common interface for the various IK smart pointer types.

◆ getAnalytical() [1/2]

InverseKinematics::Analytical * dart::dynamics::InverseKinematics::getAnalytical ( )

Get the Analytical IK method for this module, if one is available.

Analytical methods are not provided by default. If this IK module does not have an analytical method, then this will return a nullptr.

◆ getAnalytical() [2/2]

const InverseKinematics::Analytical * dart::dynamics::InverseKinematics::getAnalytical ( ) const

Get the Analytical IK method for this module, if one is available.

Analytical methods are not provided by default. If this IK module does not have an analytical method, then this will return a nullptr.

◆ getDofMap()

const std::vector< int > & dart::dynamics::InverseKinematics::getDofMap ( ) const

When a Jacobian is computed for a JacobianNode, it will include a column for every DegreeOfFreedom that the node depends on.

Given the column index of one of those dependent coordinates, this map will return its location in the mDofs vector. A value of -1 means that it is not present in the mDofs vector and therefore should not be used when performing inverse kinematics.

◆ getDofs()

const std::vector< std::size_t > & dart::dynamics::InverseKinematics::getDofs ( ) const

Get the indices of the DOFs that this IK module will use when solving.

◆ getErrorMethod() [1/2]

InverseKinematics::ErrorMethod & dart::dynamics::InverseKinematics::getErrorMethod ( )

Get the ErrorMethod for this IK module.

Every IK module always has an ErrorMethod available, so this is passed by reference.

◆ getErrorMethod() [2/2]

const InverseKinematics::ErrorMethod & dart::dynamics::InverseKinematics::getErrorMethod ( ) const

Get the ErrorMethod for this IK module.

Every IK module always has an ErrorMethod available, so this is passed by reference.

◆ getGradientMethod() [1/2]

InverseKinematics::GradientMethod & dart::dynamics::InverseKinematics::getGradientMethod ( )

Get the GradientMethod for this IK module.

Every IK module always has a GradientMethod available, so this is passed by reference.

◆ getGradientMethod() [2/2]

const InverseKinematics::GradientMethod & dart::dynamics::InverseKinematics::getGradientMethod ( ) const

Get the GradientMethod for this IK module.

Every IK module always has a GradientMethod available, so this is passed by reference.

◆ getHierarchyLevel()

std::size_t dart::dynamics::InverseKinematics::getHierarchyLevel ( ) const

Get the hierarchy level of this modle.

◆ getNode() [1/2]

JacobianNode * dart::dynamics::InverseKinematics::getNode ( )

Get the JacobianNode that this IK module operates on.

◆ getNode() [2/2]

const JacobianNode * dart::dynamics::InverseKinematics::getNode ( ) const

Get the JacobianNode that this IK module operates on.

◆ getNullSpaceObjective() [1/2]

const std::shared_ptr< optimizer::Function > & dart::dynamics::InverseKinematics::getNullSpaceObjective ( )

Get the null space objective for this IK module.

◆ getNullSpaceObjective() [2/2]

std::shared_ptr< const optimizer::Function > dart::dynamics::InverseKinematics::getNullSpaceObjective ( ) const

Get the null space objective for this IK module.

◆ getObjective() [1/2]

const std::shared_ptr< optimizer::Function > & dart::dynamics::InverseKinematics::getObjective ( )

Get the objective function for this IK module.

◆ getObjective() [2/2]

std::shared_ptr< const optimizer::Function > dart::dynamics::InverseKinematics::getObjective ( ) const

Get the objective function for this IK module.

◆ getOffset()

const Eigen::Vector3d & dart::dynamics::InverseKinematics::getOffset ( ) const

Get the offset from the origin of the body frame that will be used when performing inverse kinematics.

The offset will be expressed in the coordinates of the body frame.

◆ getPositions()

Eigen::VectorXd dart::dynamics::InverseKinematics::getPositions ( ) const

Get the current joint positions of the Skeleton.

This will only include the DOFs that have been assigned to this IK module, and the components of the vector will correspond to the components of getDofs().

◆ getProblem() [1/2]

const std::shared_ptr< optimizer::Problem > & dart::dynamics::InverseKinematics::getProblem ( )

Get the Problem that is being maintained by this IK module.

◆ getProblem() [2/2]

std::shared_ptr< const optimizer::Problem > dart::dynamics::InverseKinematics::getProblem ( ) const

Get the Problem that is being maintained by this IK module.

◆ getSolver() [1/2]

const std::shared_ptr< optimizer::Solver > & dart::dynamics::InverseKinematics::getSolver ( )

Get the Solver that is being used by this IK module.

◆ getSolver() [2/2]

std::shared_ptr< const optimizer::Solver > dart::dynamics::InverseKinematics::getSolver ( ) const

Get the Solver that is being used by this IK module.

◆ getTarget() [1/2]

std::shared_ptr< SimpleFrame > dart::dynamics::InverseKinematics::getTarget ( )

Get the target that is being used by this IK module.

You never have to check whether this is a nullptr, because it cannot ever be set to nullptr.

◆ getTarget() [2/2]

std::shared_ptr< const SimpleFrame > dart::dynamics::InverseKinematics::getTarget ( ) const

Get the target that is being used by this IK module.

You never have to check whether this is a nullptr, because it cannot ever be set to nullptr.

◆ hasNullSpaceObjective()

bool dart::dynamics::InverseKinematics::hasNullSpaceObjective ( ) const

Returns false if the null space objective does nothing.

◆ hasOffset()

bool dart::dynamics::InverseKinematics::hasOffset ( ) const

This returns false if the offset for the inverse kinematics is a zero vector.

Otherwise, it returns true. Use setOffset() to set the offset and getOffset() to get the offset.

◆ initialize()

void dart::dynamics::InverseKinematics::initialize ( )

protected

Gets called during construction.

◆ isActive()

bool dart::dynamics::InverseKinematics::isActive ( ) const

Returns true if this IK module is allowed to be active in a HierarchicalIK.

◆ operator=()

InverseKinematics& dart::dynamics::InverseKinematics::operator= ( const InverseKinematics & )

delete

Assignment is not allowed.

◆ removeObserver()

void dart::common::Subject::removeObserver ( Observer * _observer ) const

protectedinherited

Remove an Observer from the list of Observers.

◆ resetNodeConnection()

void dart::dynamics::InverseKinematics::resetNodeConnection ( )

protected

Reset the signal connection for this IK module's Node.

◆ resetProblem()

void dart::dynamics::InverseKinematics::resetProblem ( bool _clearSeeds = false )

Reset the Problem that is being maintained by this IK module.

This will clear out all Functions from the Problem and then configure the Problem to use this IK module's Objective and Constraint functions.

Setting _clearSeeds to true will clear out any seeds that have been loaded into the Problem.

◆ resetTargetConnection()

void dart::dynamics::InverseKinematics::resetTargetConnection ( )

protected

Reset the signal connection for this IK module's target.

◆ sendDestructionNotification()

void dart::common::Subject::sendDestructionNotification ( ) const

protectedinherited

Send a destruction notification to all Observers.

This will cause all Observers to behave as if this Subject has been permanently deleted, so it should only be called when that behavior is desired.

◆ setActive()

void dart::dynamics::InverseKinematics::setActive ( bool _active = true )

If this IK module is set to active, then it will be utilized by any HierarchicalIK that has it in its list.

If it is set to inactive, then it will be ignored by any HierarchicalIK holding onto it, but you can still use the solve() function with this.

◆ setDofs() [1/2]

template<class DegreeOfFreedomT >

void dart::dynamics::InverseKinematics::setDofs ( const std::vector< DegreeOfFreedomT * > & _dofs )

Explicitly set which degrees of freedom should be used to solve the IK for this module.

◆ setDofs() [2/2]

void dart::dynamics::InverseKinematics::setDofs ( const std::vector< std::size_t > & _dofs )

Explicitly set which degrees of freedom should be used to solve the IK for this module.

The values in the vector should correspond to the Skeleton indices of each DOF.

◆ setErrorMethod()

template<class IKErrorMethod , typename... Args>

IKErrorMethod & dart::dynamics::InverseKinematics::setErrorMethod ( Args &&... args )

Set the ErrorMethod for this IK module.

You can pass in arguments for the constructor, but you should ignore the constructor's first argument. The first argument of the ErrorMethod's constructor must be a pointer to this IK module, which will be automatically passed by this function.

◆ setGradientMethod()

template<class IKGradientMethod , typename... Args>

IKGradientMethod & dart::dynamics::InverseKinematics::setGradientMethod ( Args &&... args )

Set the GradientMethod for this IK module.

You can pass in arguments for the constructor, but you should ignore the constructor's first argument. The first argument of the GradientMethod's constructor must be a pointer to this IK module, which will be automatically passed by this function.

◆ setHierarchyLevel()

void dart::dynamics::InverseKinematics::setHierarchyLevel ( std::size_t _level )

Set the hierarchy level of this module.

Modules with a larger hierarchy value will be projected through the null spaces of all modules with a smaller hierarchy value. In other words, IK modules with a hierarchy level closer to 0 are given higher priority.

◆ setInactive()

void dart::dynamics::InverseKinematics::setInactive ( )

Equivalent to setActive(false)

◆ setNullSpaceObjective()

void dart::dynamics::InverseKinematics::setNullSpaceObjective ( const std::shared_ptr< optimizer::Function > & _nsObjective )

Set an objective function that should be minimized within the null space of the inverse kinematics constraint.

The gradient of this function will always be projected through the null space of this IK module's Jacobian. Pass in a nullptr to remove the null space objective.

Note: The objectives given to setObjective() and setNullSpaceObjective() will always be superimposed (added together) via the evalObjective() function.

◆ setObjective()

void dart::dynamics::InverseKinematics::setObjective ( const std::shared_ptr< optimizer::Function > & _objective )

Set an objective function that should be minimized while satisfying the inverse kinematics constraint.

Pass in a nullptr to remove the objective and make it a constant-zero function.

◆ setOffset()

void dart::dynamics::InverseKinematics::setOffset ( const Eigen::Vector3d & _offset = Eigen::Vector3d::Zero() )

Inverse kinematics can be performed on any point within the body frame.

The default point is the origin of the body frame. Use this function to change the point that will be used. _offset must represent the offset of the desired point from the body origin, expressed in coordinates of the body frame.

◆ setPositions()

void dart::dynamics::InverseKinematics::setPositions ( const Eigen::VectorXd & _q )

Set the current joint positions of the Skeleton.

This must only include the DOFs that have been assigned to this IK module, and the components of the vector must correspond to the components of getDofs().

◆ setSolver()

void dart::dynamics::InverseKinematics::setSolver ( const std::shared_ptr< optimizer::Solver > & _newSolver )

Set the Solver that should be used by this IK module, and set it up with the Problem that is configured by this IK module.

◆ setTarget()

void dart::dynamics::InverseKinematics::setTarget ( std::shared_ptr< SimpleFrame > _newTarget )

Set the target for this IK module.

Note that a target will automatically be created for the IK module upon instantiation, so you typically do not need to use this function. If you want to attach the target to an arbitrary (non-SimpleFrame) reference frame, you can do getTarget()->setParentFrame(arbitraryFrame)

◆ solve() [1/2]

bool dart::dynamics::InverseKinematics::solve ( bool applySolution = true )

Solve the IK Problem.

The initial guess for the IK optimization problem is the current joint positions of the target system. If the iterative solver fails to find a successive solution, it attempts more to solve the problem with other seed configurations or random configurations if enough seed is not provided.

Here is the pseudocode as described above:

attempts <- 0
initial_guess <- current_joint_positions
while attempts <= max_attempts:
  result <- solve(initial_guess)
  if result = success:
    return
  else:
    attempts <- attempts + 1
    if attempts <= num_seed:
      initial_guess <- seed[attempts - 1]
    else:
      initial_guess <- random_configuration  // within the bounds

By default, the max_attempts is 1, but this can be changed by calling InverseKinematics::getSolver() and casting the SolverPtr to an optimizer::GradientDescentSolver (unless you have changed the Solver type) and then calling GradientDescentSolver::setMaxAttempts(std::size_t).

By default, the list of seeds is empty, but they can be added by calling InverseKinematics::getProblem() and then using Problem::addSeed(Eigen::VectorXd).

By default, the Skeleton itself will retain the solved joint positions. If you pass in false for _applySolution, then the joint positions will be returned to their original positions after the problem is solved.

Calling this function will automatically call Position::setLowerBounds(~) and Position::setUpperBounds(~) with the lower/upper position bounds of the corresponding Degrees Of Freedom. Problem::setDimension(~) will be taken care of automatically, and Problem::setInitialGuess(~) will be called with the current positions of the Degrees Of Freedom.

Deprecated:: Deprecated in DART 6.8. Please use solveAndApply() instead.

◆ solve() [2/2]

bool dart::dynamics::InverseKinematics::solve	(	Eigen::VectorXd &	positions,
		bool	applySolution = `true`
	)

Same as solve(bool), but the positions vector will be filled with the solved positions.

Deprecated:: Deprecated in DART 6.8. Please use solveAndApply() or findSolution() instead.

◆ solveAndApply() [1/2]

bool dart::dynamics::InverseKinematics::solveAndApply ( bool allowIncompleteResult = true )

Identical to findSolution(), but this function applies the solution when the solver successfully found a solution or allowIncompleteResult is set to true.

Parameters

[in] allowIncompleteResult Allow to apply the solution even when the solver failed to find solution. This option would be useful when an iterative solver is used because they will often do a decent job of getting a result close to a solution even if it failed to find the solution.

Returns: True if a solution is successfully found

◆ solveAndApply() [2/2]

bool dart::dynamics::InverseKinematics::solveAndApply	(	Eigen::VectorXd &	positions,
		bool	allowIncompleteResult = `true`
	)

Identical to solveAndApply(bool), but position will be filled with the solved positions.

Parameters

[out]	positions	The solution of the IK problem. If the solver failed to find a solution then it will still set the position with the best guess. For example, iterative solvers will fill `positions` with the last result of the iterations.
[in]	allowIncompleteResult	Allow to apply the solution even when the solver failed to find solution. This option would be useful when an iterative solver is used because they will often do a decent job of getting a result close to a solution even if it failed to find the solution.

Returns: True if a solution is successfully found

◆ useChain()

void dart::dynamics::InverseKinematics::useChain ( )

When solving the IK for this module's Node, use the longest available dynamics::Chain that goes from this module's Node towards the root of the Skeleton.

Using this will prevent any other branches in the Skeleton from being affected by this IK module.

◆ useWholeBody()

void dart::dynamics::InverseKinematics::useWholeBody ( )

Use all relevant joints on the Skeleton to solve the IK.

Friends And Related Function Documentation

◆ Constraint

friend class Constraint

friend

◆ Objective

friend class Objective

friend

Member Data Documentation

◆ mActive

bool dart::dynamics::InverseKinematics::mActive

protected

True if this IK module should be active in its IK hierarcy.

◆ mAnalytical

Analytical* dart::dynamics::InverseKinematics::mAnalytical

protected

If mGradientMethod is an Analytical extension, then this will have the same value is mGradientMethod.

Otherwise, this will be a nullptr.

Note that this pointer's memory does not need to be managed, because it is always either nullptr or a reference to mGradientMethod.

◆ mDofMap

std::vector<int> dart::dynamics::InverseKinematics::mDofMap

protected

Map for the DOFs that are to be used by this IK module.

◆ mDofs

std::vector<std::size_t> dart::dynamics::InverseKinematics::mDofs

protected

A list of the DegreeOfFreedom Skeleton indices that will be used by this IK module.

◆ mErrorMethod

std::unique_ptr<ErrorMethod> dart::dynamics::InverseKinematics::mErrorMethod

protected

The method that this IK module will use to compute errors.

◆ mGradientMethod

std::unique_ptr<GradientMethod> dart::dynamics::InverseKinematics::mGradientMethod

protected

The method that this IK module will use to compute gradients.

◆ mHasOffset

bool dart::dynamics::InverseKinematics::mHasOffset

protected

True if the offset is non-zero.

◆ mHierarchyLevel

std::size_t dart::dynamics::InverseKinematics::mHierarchyLevel

protected

Hierarchy level for this IK module.

◆ mJacobian

math::Jacobian dart::dynamics::InverseKinematics::mJacobian

mutableprotected

Jacobian cache for the IK module.

◆ mNode

sub_ptr<JacobianNode> dart::dynamics::InverseKinematics::mNode

protected

JacobianNode that this IK module is associated with.

◆ mNodeConnection

common::Connection dart::dynamics::InverseKinematics::mNodeConnection

protected

Connection to the node update.

◆ mNullSpaceObjective

std::shared_ptr<optimizer::Function> dart::dynamics::InverseKinematics::mNullSpaceObjective

protected

Null space objective for the IK module.

◆ mObjective

std::shared_ptr<optimizer::Function> dart::dynamics::InverseKinematics::mObjective

protected

Objective for the IK module.

◆ mObservers

std::set<Observer*> dart::common::Subject::mObservers

mutableprotectedinherited

List of current Observers.

◆ mOffset

Eigen::Vector3d dart::dynamics::InverseKinematics::mOffset

protected

The offset that this IK module should use when computing IK.

◆ mProblem

std::shared_ptr<optimizer::Problem> dart::dynamics::InverseKinematics::mProblem

protected

The Problem that will be maintained by this IK module.

◆ mSolver

std::shared_ptr<optimizer::Solver> dart::dynamics::InverseKinematics::mSolver

protected

The solver that this IK module will use for iterative methods.

◆ mTarget

std::shared_ptr<SimpleFrame> dart::dynamics::InverseKinematics::mTarget

protected

Target that this IK module should use.

◆ mTargetConnection

common::Connection dart::dynamics::InverseKinematics::mTargetConnection

protected

Connection to the target update.

Classes

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ InverseKinematics() [1/2]

◆ ~InverseKinematics()

◆ InverseKinematics() [2/2]

Member Function Documentation

◆ addObserver()

◆ clearCaches()

◆ clone()

◆ computeJacobian()

◆ create()

◆ findSolution()

◆ getAffiliation() [1/2]

◆ getAffiliation() [2/2]

◆ getAnalytical() [1/2]

◆ getAnalytical() [2/2]

◆ getDofMap()

◆ getDofs()

◆ getErrorMethod() [1/2]

◆ getErrorMethod() [2/2]

◆ getGradientMethod() [1/2]

◆ getGradientMethod() [2/2]

◆ getHierarchyLevel()

◆ getNode() [1/2]

◆ getNode() [2/2]

◆ getNullSpaceObjective() [1/2]

◆ getNullSpaceObjective() [2/2]

◆ getObjective() [1/2]

◆ getObjective() [2/2]

◆ getOffset()

◆ getPositions()

◆ getProblem() [1/2]

◆ getProblem() [2/2]

◆ getSolver() [1/2]

◆ getSolver() [2/2]

◆ getTarget() [1/2]

◆ getTarget() [2/2]

◆ hasNullSpaceObjective()

◆ hasOffset()

◆ initialize()

◆ isActive()

◆ operator=()

◆ removeObserver()

◆ resetNodeConnection()

◆ resetProblem()

◆ resetTargetConnection()

◆ sendDestructionNotification()

◆ setActive()

◆ setDofs() [1/2]

◆ setDofs() [2/2]

◆ setErrorMethod()

◆ setGradientMethod()

◆ setHierarchyLevel()

◆ setInactive()

◆ setNullSpaceObjective()

◆ setObjective()

◆ setOffset()

◆ setPositions()

◆ setSolver()

◆ setTarget()

◆ solve() [1/2]

◆ solve() [2/2]

◆ solveAndApply() [1/2]

◆ solveAndApply() [2/2]

◆ useChain()

◆ useWholeBody()

Friends And Related Function Documentation

◆ Constraint

◆ Objective

Member Data Documentation

◆ mActive

◆ mAnalytical

◆ mDofMap

◆ mDofs