Minimize the error between a model's step time asymmetry and a specified target asymmetry value over a gait cycle. More...

Inheritance diagram for OpenSim::MocoStepLengthAsymmetryGoal:

OpenSim Properties, Sockets, Outputs, Inputs
Properties (single-value)
std::string	left_foot_frame
	"The model frame associated with the left foot." More...

std::string	right_foot_frame
	"The model frame associated with the right foot." More...

double	target_asymmetry
	"The target asymmetry value, between -1.0 and 1.0. Positive " "asymmetry is associated with the right leg, and negative asymmetry " "for the left. Default: 0" More...

double	asymmetry_smoothing
	"The value that determines the smoothing of the asymmetry " "computation. Larger values mean that larger step length errors are " "required for a step to be counted towards the asymmetry error. " "Default: 5." More...

double	stride_length
	"The known stride length of the simulation, in meters." "Default is -1; the user must provide a positive value." More...

std::string	walking_direction
	"The walking direction of the model in the ground frame, which " "is used to determine the leading foot during double support. " "Acceptable direction values include 'positive-x', 'positive-y', " "'positive-z', 'negative-x', 'negative-y', and 'negative-z'. " "Default: 'positive-x'." More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::MocoGoal
bool	enabled
	"This bool indicates whether this goal is enabled." More...

double	weight
	"In cost mode, the goal is multiplied by this weight (default: " "1)." More...

std::string	mode
	"'cost' to enforce as a penalty, 'endpoint_constraint' to enforce " "as a constraint." More...

MocoConstraintInfo	MocoConstraintInfo
	"The bounds and labels for this MocoGoal, if applied as an " "endpoint constraint." More...

MocoScaleFactor	scale_factors
	"Scale factors added by derived MocoGoal classes that are optimized " "via a MocoParameter. A copy of each MocoScaleFactor component is " "added to the model internal to MocoProblem, which makes the scale " "factors values available when computing the cost function for each " "MocoGoal." More...

Public Member Functions
	MocoStepLengthAsymmetryGoal ()

	MocoStepLengthAsymmetryGoal (std::string name)

	MocoStepLengthAsymmetryGoal (std::string name, double weight)

void	setLeftFootFrame (const std::string &frame)
	Set the body frame associated with the left foot. More...

std::string	getLeftFootFrame ()

void	setRightFootFrame (const std::string &frame)
	Set the body frame associated with the right foot. More...

std::string	getRightFootFrame ()

void	setTargetAsymmetry (double asymmetry)
	Set the asymmetry value targeted by this goal. More...

double	getTargetAsymmetry ()

void	setStrideLength (double length)
	Set the known stride length of your walking simulation. More...

double	getStrideLength ()

void	setWalkingDirection (const std::string &direction)
	Set the walking direction of the model in the ground frame, which is used to compute step lengths. More...

std::string	getWalkingDirection ()

void	setAsymmetrySmoothing (double smoothing)
	Set the values that determines the smoothing of the asymmetry computation. More...

double	getAsymmetrySmoothing ()

Public Member Functions inherited from OpenSim::MocoGoal
	MocoGoal ()

	MocoGoal (std::string name)

	MocoGoal (std::string name, double weight)

void	setEnabled (bool enabled)
	Set whether this goal is used in the problem. More...

bool	getEnabled () const

void	setWeight (double weight)
	In cost mode, the goal is multiplied by this weight. More...

double	getWeight () const

void	setMode (std::string mode)
	Set the mode property to either 'cost' or 'endpoint_constraint'. More...

std::string	getModeAsString () const
	This returns the default mode of the goal, unless the user overrode the default using setMode(). More...

Mode	getMode () const

bool	getModeIsCost () const

bool	getModeIsEndpointConstraint () const

Mode	getDefaultMode () const
	Types of goals have a class-level default for whether they are enforced as a cost or endpoint constraint. More...

bool	getSupportsEndpointConstraint () const
	Can this goal be used in endpoint constraint mode? More...

const MocoConstraintInfo &	getConstraintInfo () const
	Get bounds for the constraints that are enforced when using this goal in endpoint constraint mode. More...

MocoConstraintInfo &	updConstraintInfo ()

int	getNumOutputs () const
	Get the length of the return value of calcGoal(). More...

int	getNumIntegrals () const
	Get the number of integrals required by this cost. More...

SimTK::Stage	getStageDependency () const
	Obtain the stage that this goal depends on. More...

SimTK::Real	calcIntegrand (const IntegrandInput &input) const
	Calculate the integrand that should be integrated and passed to calcCost(). More...

void	calcGoal (const GoalInput &input, SimTK::Vector &goal) const
	In cost mode, the returned cost includes the weight, and the elements of the returned vector should be summed by the caller to obtain the total cost. More...

void	initializeOnModel (const Model &model) const
	Perform error checks on user input for this goal, and cache quantities needed when computing the goal value. More...

std::vector< MocoScaleFactor >	getScaleFactors () const
	Get a vector of the MocoScaleFactors added to this MocoGoal. More...

void	printDescription () const
	Print the name type and mode of this goal. More...

Public Member Functions inherited from OpenSim::Object
virtual	~Object ()
	Virtual destructor for cleanup. More...

bool	isEqualTo (const Object &aObject) const
	Equality operator wrapper for use from languages not supporting operator overloading. More...

Object &	operator= (const Object &aObject)
	Copy assignment copies he base class fields, including the properties. More...

virtual bool	operator== (const Object &aObject) const
	Determine if two objects are equal. More...

virtual bool	operator< (const Object &aObject) const
	Provide an ordering for objects so they can be put in sorted containers. More...

void	setName (const std::string &name)
	Set the name of the Object. More...

const std::string &	getName () const
	Get the name of this Object. More...

void	setDescription (const std::string &description)
	Set description, a one-liner summary. More...

const std::string &	getDescription () const
	Get description, a one-liner summary. More...

const std::string &	getAuthors () const
	Get Authors of this Object. More...

void	setAuthors (const std::string &authors)
	Set Authors of this object. More...

const std::string &	getReferences () const
	Get references or publications to cite if using this object. More...

void	setReferences (const std::string &references)
	Set references or publications to cite if using this object. More...

int	getNumProperties () const
	Determine how many properties are stored with this Object. More...

const AbstractProperty &	getPropertyByIndex (int propertyIndex) const
	Get a const reference to a property by its index number, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByIndex (int propertyIndex)
	Get a writable reference to a property by its index number, returned as an AbstractProperty. More...

bool	hasProperty (const std::string &name) const
	Return true if this Object has a property of any type with the given name, which must not be empty. More...

const AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByName (const std::string &name)
	Get a writable reference to a property by its name, returned as an AbstractProperty. More...

template<class T >
bool	hasProperty () const
	Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...

template<class T >
const Property< T > &	getProperty (const PropertyIndex &index) const
	Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...

template<class T >
Property< T > &	updProperty (const PropertyIndex &index)
	Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...

bool	isObjectUpToDateWithProperties () const
	Returns `true` if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...

void	readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
	We're given an XML element from which we are to populate this Object. More...

virtual void	updateFromXMLNode (SimTK::Xml::Element &objectElement, int versionNumber)
	Use this method to deserialize an object from a SimTK::Xml::Element. More...

void	updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
	Serialize this object into the XML node that represents it. More...

bool	getInlined () const
	Inlined means an in-memory Object that is not associated with an XMLDocument. More...

void	setInlined (bool aInlined, const std::string &aFileName="")
	Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...

std::string	getDocumentFileName () const
	If there is a document associated with this object then return the file name maintained by the document. More...

int	getDocumentFileVersion () const
	If there is a document associated with this object then return its version number. More...

void	setAllPropertiesUseDefault (bool aUseDefault)

bool	print (const std::string &fileName) const
	Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...

std::string	dump () const
	dump the XML representation of this Object into an std::string and return it. More...

virtual bool	isA (const char *type) const
	The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...

const std::string &	toString () const
	Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...

PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...

const PropertySet &	getPropertySet () const

Auto-generated functions
static MocoStepLengthAsymmetryGoal *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

static const std::string &	getClassName ()
	This returns "MocoStepLengthAsymmetryGoal". More...

MocoStepLengthAsymmetryGoal *	clone () const override
	Create a new heap-allocated copy of the concrete object to which this Object refers. More...

const std::string &	getConcreteClassName () const override
	Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

Additional Inherited Members
Static Public Member Functions inherited from OpenSim::MocoGoal
static MocoGoal *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

static const std::string &	getClassName ()
	This returns "MocoGoal". More...

Static Public Member Functions inherited from OpenSim::Object
static void	registerType (const Object &defaultObject)
	Register an instance of a class; if the class is already registered it will be replaced. More...

static void	renameType (const std::string &oldTypeName, const std::string &newTypeName)
	Support versioning by associating the current Object type with an old name. More...

static const Object *	getDefaultInstanceOfType (const std::string &concreteClassName)
	Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More...

template<class T >
static bool	isObjectTypeDerivedFrom (const std::string &concreteClassName)
	Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More...

static Object *	newInstanceOfType (const std::string &concreteClassName)
	Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...

static void	getRegisteredTypenames (Array< std::string > &typeNames)
	Retrieve all the typenames registered so far. More...

template<class T >
static void	getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
	Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...

static bool	PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
	Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...

static bool	PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
	Same as the other signature but the class name and property name are provided as two separate strings. More...

static Object *	makeObjectFromFile (const std::string &fileName)
	Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...

static const std::string &	getClassName ()
	Return the name of this class as a string; i.e., "Object". More...

static void	setSerializeAllDefaults (bool shouldSerializeDefaults)
	Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...

static bool	getSerializeAllDefaults ()
	Report the value of the "serialize all defaults" flag. More...

static bool	isKindOf (const char *type)
	Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...

static void	setDebugLevel (int newLevel)
	Set the amount of logging output. More...

static int	getDebugLevel ()
	Get the current setting of debug level. More...

static Object *	SafeCopy (const Object *aObject)
	Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...

static void	RegisterType (const Object &defaultObject)
	OBSOLETE alternate name for registerType(). More...

static void	RenameType (const std::string &oldName, const std::string &newName)
	OBSOLETE alternate name for renameType(). More...

Detailed Description

Minimize the error between a model's step time asymmetry and a specified target asymmetry value over a gait cycle.

Step Length Asymmetry (SLA) is a ratio and is calculated as follows: The Right Step Length (RSL) is the distance between feet at right foot strike The Left Step Length (LSL) is the distance between feet at left foot strike Step Length Asymmetry = (RSL - LSL) / (RSL + LSL)

In this goal, the distance between feet, or "foot frames", is limited throughout the gait cycle. The goal calculates the distance between the left foot and right foot, then limits the distance between feet to not pass beyond minimum (negative) or maximum (positive) bounds. There are two limits used: one that limits the distance between feet when the right foot is in front, and one that limits the distance between feet when the left foot is in front.

Users must provide the target asymmetry value via 'setTargetAsymmetry()'. Asymmetry values ranges from -1.0 to 1.0. For example, 0.20 is 20% positive step length asymmetry with greater right step length than left step length. A symmetric step length solution can be achieved by setting this property to zero. This goal can be used only in 'cost' mode. To make this goal suitable for gradient-based optimization, step length values are assigned via a smoothing function which can be controlled via 'setAsymmetrySmoothing()'.

Users must also prescribe the stride length via 'setStrideLength()'. The goal then calculates the minimum and maximum bounds on the distance between right and left foot. Users must ensure that this stride length is met via problem bounds or other goals; the value provided to MocoStepLengthAsymmetryGoal is only used to compute the model's asymmetry in the cost function.

Note: This goal is designed for simulations of bipedal gait.; Since this goal approximates step length asymmetry, users should calculate the true asymmetry value after running an optimization.

Constructor & Destructor Documentation

◆ MocoStepLengthAsymmetryGoal() [1/3]

OpenSim::MocoStepLengthAsymmetryGoal::MocoStepLengthAsymmetryGoal ( )

inline

◆ MocoStepLengthAsymmetryGoal() [2/3]

OpenSim::MocoStepLengthAsymmetryGoal::MocoStepLengthAsymmetryGoal ( std::string name )

inline

◆ MocoStepLengthAsymmetryGoal() [3/3]

OpenSim::MocoStepLengthAsymmetryGoal::MocoStepLengthAsymmetryGoal	(	std::string	name,
		double	weight
	)

inline

Member Function Documentation

◆ calcGoalImpl()

void OpenSim::MocoStepLengthAsymmetryGoal::calcGoalImpl	(	const GoalInput &	input,
		SimTK::Vector &	goal
	)		const

overrideprotectedvirtual

You may need to realize the state to the stage required for your calculations.

Do NOT realize to a stage higher than the goal's stage dependency; doing so will cause an exception to be thrown. The Lagrange multipliers for kinematic constraints are not available.

Implements OpenSim::MocoGoal.

◆ calcIntegrandImpl()

void OpenSim::MocoStepLengthAsymmetryGoal::calcIntegrandImpl	(	const IntegrandInput &	input,
		double &	integrand
	)		const

overrideprotected

◆ clone()

MocoStepLengthAsymmetryGoal* OpenSim::MocoStepLengthAsymmetryGoal::clone ( ) const

inlineoverridevirtual

Create a new heap-allocated copy of the concrete object to which this Object refers.

It is up to the caller to delete the returned object when no longer needed. Every concrete object deriving from Object implements this pure virtual method automatically, via the declaration macro it invokes (e.g., OpenSim_DECLARE_CONCRETE_OBJECT()). Note that the concrete class overrides modify the return type to be a pointer to the concrete object; that still overrides the base class method because the return type is covariant with (that is, derives from) Object.

Implements OpenSim::MocoGoal.

◆ getAsymmetrySmoothing()

double OpenSim::MocoStepLengthAsymmetryGoal::getAsymmetrySmoothing ( )

inline

◆ getClassName()

static const std::string& OpenSim::MocoStepLengthAsymmetryGoal::getClassName ( )

inlinestatic

This returns "MocoStepLengthAsymmetryGoal".

See getConcreteClassName() if you want the class name of the underlying concrete object instead.

◆ getConcreteClassName()

const std::string& OpenSim::MocoStepLengthAsymmetryGoal::getConcreteClassName ( ) const

inlineoverridevirtual

Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string.

This is the string that is used as the tag for this concrete object in an XML file. Every concrete class derived from Object automatically overrides this method via the declaration macro it uses. See getClassName() to get the class name of the referencing (possibly abstract) class rather than the concrete object.

See also: getClassName()

Implements OpenSim::MocoGoal.

◆ getLeftFootFrame()

std::string OpenSim::MocoStepLengthAsymmetryGoal::getLeftFootFrame ( )

inline

◆ getRightFootFrame()

std::string OpenSim::MocoStepLengthAsymmetryGoal::getRightFootFrame ( )

inline

◆ getStrideLength()

double OpenSim::MocoStepLengthAsymmetryGoal::getStrideLength ( )

inline

◆ getTargetAsymmetry()

double OpenSim::MocoStepLengthAsymmetryGoal::getTargetAsymmetry ( )

inline

◆ getWalkingDirection()

std::string OpenSim::MocoStepLengthAsymmetryGoal::getWalkingDirection ( )

inline

◆ initializeOnModelImpl()

void OpenSim::MocoStepLengthAsymmetryGoal::initializeOnModelImpl ( const Model & ) const

overrideprotectedvirtual

Perform any caching before the problem is solved.

You must override this function and invoke setRequirements().

Precondition(s):: The model is initialized (initSystem()) and getModel() is available. The passed-in model is equivalent to getModel(). Use this opportunity to check for errors in user input.

Implements OpenSim::MocoGoal.

◆ printDescriptionImpl()

void OpenSim::MocoStepLengthAsymmetryGoal::printDescriptionImpl ( ) const

overrideprotectedvirtual

Print a more detailed description unique to each goal.

Reimplemented from OpenSim::MocoGoal.

◆ safeDownCast()

static MocoStepLengthAsymmetryGoal* OpenSim::MocoStepLengthAsymmetryGoal::safeDownCast ( OpenSim::Object * obj )

inlinestatic

For use in MATLAB and Python to access the concrete class.

Example: cObj = MocoStepLengthAsymmetryGoal.safeDownCast(obj). This is equivalent to dynamic_cast<MocoStepLengthAsymmetryGoal*>(obj) in C++.

◆ setAsymmetrySmoothing()

void OpenSim::MocoStepLengthAsymmetryGoal::setAsymmetrySmoothing ( double smoothing )

inline

Set the values that determines the smoothing of the asymmetry computation.

This term is necessary since this computation is non-smooth. Larger smoothing values mean that larger step length errors are required for a given step to be counted towards the total asymmetry error minimized in the cost.

◆ setLeftFootFrame()

void OpenSim::MocoStepLengthAsymmetryGoal::setLeftFootFrame ( const std::string & frame )

inline

Set the body frame associated with the left foot.

◆ setRightFootFrame()

void OpenSim::MocoStepLengthAsymmetryGoal::setRightFootFrame ( const std::string & frame )

inline

Set the body frame associated with the right foot.

◆ setStrideLength()

void OpenSim::MocoStepLengthAsymmetryGoal::setStrideLength ( double length )

inline

Set the known stride length of your walking simulation.

This value is necessary to compute step length asymmetry.

◆ setTargetAsymmetry()

void OpenSim::MocoStepLengthAsymmetryGoal::setTargetAsymmetry ( double asymmetry )

inline

Set the asymmetry value targeted by this goal.

The error between the target asymmetry and the model asymmetry is squared in the integrand.

◆ setWalkingDirection()

void OpenSim::MocoStepLengthAsymmetryGoal::setWalkingDirection ( const std::string & direction )

inline

Set the walking direction of the model in the ground frame, which is used to compute step lengths.

Acceptable direction values include "positive-x", "positive-y", "positive-z", "negative-x", "negative-y", and "negative-z". Default: "positive-x".

OpenSim Property, Socket, Output, Input Documentation

◆ asymmetry_smoothing

double OpenSim::MocoStepLengthAsymmetryGoal::asymmetry_smoothing

"The value that determines the smoothing of the asymmetry " "computation. Larger values mean that larger step length errors are " "required for a step to be counted towards the asymmetry error. " "Default: 5."

This property appears in XML files under the tag <asymmetry_smoothing>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_asymmetry_smoothing(), upd_asymmetry_smoothing(), set_asymmetry_smoothing()

◆ left_foot_frame

std::string OpenSim::MocoStepLengthAsymmetryGoal::left_foot_frame

"The model frame associated with the left foot."

This property appears in XML files under the tag <left_foot_frame>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_left_foot_frame(), upd_left_foot_frame(), set_left_foot_frame()

◆ right_foot_frame

std::string OpenSim::MocoStepLengthAsymmetryGoal::right_foot_frame

"The model frame associated with the right foot."

This property appears in XML files under the tag <right_foot_frame>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_right_foot_frame(), upd_right_foot_frame(), set_right_foot_frame()

◆ stride_length

double OpenSim::MocoStepLengthAsymmetryGoal::stride_length

"The known stride length of the simulation, in meters." "Default is -1; the user must provide a positive value."

This property appears in XML files under the tag <stride_length>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_stride_length(), upd_stride_length(), set_stride_length()

◆ target_asymmetry

double OpenSim::MocoStepLengthAsymmetryGoal::target_asymmetry

"The target asymmetry value, between -1.0 and 1.0. Positive " "asymmetry is associated with the right leg, and negative asymmetry " "for the left. Default: 0"

This property appears in XML files under the tag <target_asymmetry>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_target_asymmetry(), upd_target_asymmetry(), set_target_asymmetry()

◆ walking_direction

std::string OpenSim::MocoStepLengthAsymmetryGoal::walking_direction

"The walking direction of the model in the ground frame, which " "is used to determine the leading foot during double support. " "Acceptable direction values include 'positive-x', 'positive-y', " "'positive-z', 'negative-x', 'negative-y', and 'negative-z'. " "Default: 'positive-x'."

This property appears in XML files under the tag <walking_direction>. This property was generated with the OpenSim_DECLARE_PROPERTY macro; see Property to learn about the property system.

See also: get_walking_direction(), upd_walking_direction(), set_walking_direction()

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

OpenSim/Moco/MocoGoal/MocoStepLengthAsymmetryGoal.h

OpenSim Properties, Sockets, Outputs, Inputs

Public Member Functions

Auto-generated functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MocoStepLengthAsymmetryGoal() [1/3]

◆ MocoStepLengthAsymmetryGoal() [2/3]

◆ MocoStepLengthAsymmetryGoal() [3/3]

Member Function Documentation

◆ calcGoalImpl()

◆ calcIntegrandImpl()

◆ clone()

◆ getAsymmetrySmoothing()

◆ getClassName()

◆ getConcreteClassName()

◆ getLeftFootFrame()

◆ getRightFootFrame()

◆ getStrideLength()

◆ getTargetAsymmetry()

◆ getWalkingDirection()

◆ initializeOnModelImpl()

◆ printDescriptionImpl()

◆ safeDownCast()

◆ setAsymmetrySmoothing()

◆ setLeftFootFrame()

◆ setRightFootFrame()

◆ setStrideLength()

◆ setTargetAsymmetry()

◆ setWalkingDirection()

OpenSim Property, Socket, Output, Input Documentation

◆ asymmetry_smoothing

◆ left_foot_frame

◆ right_foot_frame

◆ stride_length

◆ target_asymmetry

◆ walking_direction