This class serves as a serializable ForceVelocityCurve for use in muscle models. More...

Inheritance diagram for OpenSim::ForceVelocityCurve:

Public Member Functions
	ForceVelocityCurve ()
	The default constructor creates a force-velocity curve using the default property values and assigns a default name. More...

	ForceVelocityCurve (double concentricSlopeAtVmax, double concentricSlopeNearVmax, double isometricSlope, double eccentricSlopeAtVmax, double eccentricSlopeNearVmax, double maxEccentricVelocityForceMultiplier, double concentricCurviness, double eccentricCurviness)
	Constructs a force-velocity curve using the provided parameters and assigns a default name. More...

double	getConcentricSlopeAtVmax () const

double	getConcentricSlopeNearVmax () const

double	getIsometricSlope () const

double	getEccentricSlopeAtVmax () const

double	getEccentricSlopeNearVmax () const

double	getMaxEccentricVelocityForceMultiplier () const

double	getConcentricCurviness () const

double	getEccentricCurviness () const

void	setCurveShape (double aConcentricSlopeAtVmax, double aConcentricSlopeNearVmax, double aIsometricSlope, double aEccentricSlopeAtVmax, double aEccentricSlopeNearVmax, double aMaxForceMultiplier)

void	setConcentricCurviness (double aConcentricCurviness)

void	setEccentricCurviness (double aEccentricCurviness)

double	calcValue (const SimTK::Vector &x) const override
	Implement the generic OpenSim::Function interface. More...

double	calcValue (double normFiberVelocity) const
	Evaluates the force-velocity curve at a normalized fiber velocity of 'normFiberVelocity'. More...

double	calcDerivative (double normFiberVelocity, int order) const
	Calculates the derivative of the force-velocity multiplier with respect to the normalized fiber velocity. More...

SimTK::Vec2	getCurveDomain () const
	Returns a SimTK::Vec2 containing the lower (0th element) and upper (1st element) bounds on the domain of the curve. More...

void	printMuscleCurveToCSVFile (const std::string &path)
	Generates a .csv file with a name that matches the curve name (e.g., "bicepsfemoris_ForceVelocityCurve.csv"). More...

void	ensureCurveUpToDate ()

Property declarations
These are the serializable properties associated with this class.
	OpenSim_DECLARE_PROPERTY (concentric_slope_at_vmax, double,"Curve slope at the maximum normalized concentric (shortening) velocity (normalized velocity of -1)")

	OpenSim_DECLARE_PROPERTY (concentric_slope_near_vmax, double,"Curve slope just before reaching concentric_slope_at_vmax")

	OpenSim_DECLARE_PROPERTY (isometric_slope, double,"Curve slope at isometric (normalized velocity of 0)")

	OpenSim_DECLARE_PROPERTY (eccentric_slope_at_vmax, double,"Curve slope at the maximum normalized eccentric (lengthening) velocity (normalized velocity of 1)")

	OpenSim_DECLARE_PROPERTY (eccentric_slope_near_vmax, double,"Curve slope just before reaching eccentric_slope_at_vmax")

	OpenSim_DECLARE_PROPERTY (max_eccentric_velocity_force_multiplier, double,"Curve value at the maximum normalized eccentric contraction velocity")

	OpenSim_DECLARE_PROPERTY (concentric_curviness, double,"Concentric curve shape, from linear (0) to maximal curve (1)")

	OpenSim_DECLARE_PROPERTY (eccentric_curviness, double,"Eccentric curve shape, from linear (0) to maximal curve (1)")

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

	Function (const Function &aFunction)

virtual	~Function ()

virtual void	init (Function *aFunction)

Function &	operator= (const Function &aFunction)

virtual double	calcDerivative (const std::vector< int > &derivComponents, const SimTK::Vector &x) const
	Calculate a partial derivative of this function at a particular point. More...

virtual int	getArgumentSize () const
	Get the number of components expected in the input vector. More...

virtual int	getMaxDerivativeOrder () const
	Get the maximum derivative order this Function object can calculate. More...

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

virtual Object *	clone () const =0
	Create a new heap-allocated copy of the concrete object to which this Object refers. More...

virtual const std::string &	getConcreteClassName () const =0
	Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

virtual const VisibleObject *	getDisplayer () const
	Methods to support making the object displayable in the GUI or Visualizer Implemented only in few objects. More...

virtual VisibleObject *	updDisplayer ()
	get Non const pointer to VisibleObject 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, call this method in your constructor if needed. 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...

void	setObjectIsUpToDateWithProperties ()
	When an object is initialized using the current values of its properties, it can set a flag indicating that it is up to date. 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...

virtual void	updateXMLNode (SimTK::Xml::Element &parent)
	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...

void	setAllPropertiesUseDefault (bool aUseDefault)

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

std::string	dump (bool dumpName=false)
	dump the XML representation of this Object into an std::string and return it. More...

void	clearObjectIsUpToDateWithProperties ()
	For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag. 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

Additional Inherited Members
Static Public Member Functions inherited from OpenSim::Function
static Function *	makeFunctionOfType (Function *aFunction, const std::string &aNewTypeName)

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

static void	PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName)
	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 debug level to get verbose output. More...

static int	getDebugLevel ()
	Get 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...

Static Public Attributes inherited from OpenSim::Object
static const std::string	DEFAULT_NAME
	Name used for default objects when they are serialized. More...

Protected Member Functions inherited from OpenSim::Function
void	resetFunction ()
	This should be called whenever this object has been modified. More...

Protected Member Functions inherited from OpenSim::Object
	Object ()
	The default constructor is only for use by constructors of derived types. More...

	Object (const std::string &fileName, bool aUpdateFromXMLNode=true) SWIG_DECLARE_EXCEPTION
	Constructor from a file, to be called from other constructors that take a file as input. More...

	Object (const Object &source)
	Copy constructor is invoked automatically by derived classes with default copy constructors; otherwise it must be invoked explicitly. More...

	Object (SimTK::Xml::Element &aElement)
	Construct the base class portion of an Object from a given Xml element that describes this Object. More...

template<class T >
PropertyIndex	addProperty (const std::string &name, const std::string &comment, const T &value)
	Define a new single-value property of known type T, with the given name, associated comment, and initial value. More...

template<class T >
PropertyIndex	addOptionalProperty (const std::string &name, const std::string &comment)
	Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex	addOptionalProperty (const std::string &name, const std::string &comment, const T &value)
	Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex	addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize)
	Define a new list-valued property of known type T, with the given name, associated comment, minimum (==0) and maximum (>0) allowable list lengths, and a zero-length initial value. More...

template<class T , template< class > class Container>
PropertyIndex	addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize, const Container< T > &valueList)
	Define a new list-valued property as above, but assigning an initial value via some templatized container class that supports size() and indexing. More...

PropertyIndex	getPropertyIndex (const std::string &name) const
	Look up a property by name and return its PropertyIndex if it is found. More...

template<class T >
PropertyIndex	getPropertyIndex () const
	Look up an unnamed property by the type of object it contains, and return its PropertyIndex if it is found. More...

void	updateFromXMLDocument ()
	Use this method only if you're deserializing from a file and the object is at the top level; that is, primarily in constructors that take a file name as input. More...

void	setDocument (XMLDocument *doc)
	Unconditionally set the XMLDocument associated with this object. More...

const XMLDocument *	getDocument () const
	Get a const pointer to the document (if any) associated with this object. More...

XMLDocument *	updDocument ()
	Get a writable pointer to the document (if any) associated with this object. More...

Protected Attributes inherited from OpenSim::Function
SimTK::Function *	_function

Protected Attributes inherited from OpenSim::Object
PropertySet	_propertySet
	OBSOLETE: Property_Deprecated set for serializable member variables of this and derived classes. More...

Related Functions inherited from OpenSim::Object
#define	OpenSim_DECLARE_CONCRETE_OBJECT(ConcreteClass, SuperClass)
	Macro to be included as the first line of the class declaration for any non-templatized, concrete class that derives from OpenSim::Object. More...

#define	OpenSim_DECLARE_ABSTRACT_OBJECT(ConcreteClass, SuperClass)
	Macro to be included as the first line of the class declaration for any still-abstract class that derives from OpenSim::Object. More...

#define	OpenSim_DECLARE_CONCRETE_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, concrete class that derives from OpenSim::Object, like Set<T>. More...

#define	OpenSim_DECLARE_ABSTRACT_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, still-abstract class that derives from OpenSim::Object. More...

Detailed Description

This class serves as a serializable ForceVelocityCurve for use in muscle models.

The force-velocity curve is dimensionless: force is normalized to maximum isometric force and velocity is normalized to the maximum muscle contraction velocity (vmax), where vmax is expressed in units of optimal_fiber_lengths per second. Negative normalized velocities correspond to concentric contraction (i.e., shortening). The force-velocity curve is constructed from 8 properties:

Parameters

concentricSlopeAtVmax	The slope of the force-velocity curve at a normalized velocity of -1, which is the minimum slope of the concentric side of the force-velocity curve. A physiologically accurate value for this paramter is 0, though values greater than 0 are necessary when the force-velocity curve must be inverted.
concentricSlopeNearVmax	The slope of the force-velocity curve near the maximum normalized concentric (shortening) contraction velocity (between approximately -0.8 and -1).
isometricSlope	The slope of the force-velocity curve at a normalized velocity of 0, which is the maximum slope of the force-velocity curve. A physiologically accurate value for this parameter is 5 (according to Leiber, page 55), which is the default value. Although this parameter can be changed, it must be positive and greater than max( (maxEccentricMultiplier-1)/1, 1). The value of this parameter also affects how much the eccentric and concentric curves can be bent by the 'eccentricCurviness' and 'concentricCurviness' parameters, as it places an upper limit on the maximum slope of the force-velocity curve.
eccentricSlopeAtVmax	The slope of the force-velocity curve at a normalized velocity of 1, which is the minimum slope of the eccentric side of the force-velocity curve.
eccentricSlopeNearVmax	The slope of the force-velocity curve near the maximum normalized eccentric (lengthening) contraction velocity (between approximately 0.8 and 1).
maxEccentricVelocityForceMultiplier	The value of the force-velocity curve (i.e., the force-velocity multiplier) at the maximum eccentric contraction velocity. Physiologically acccurate values for this parameter range between 1.1 and 1.8, and may vary between subjects.
concentricCurviness	A dimensionless parameter between 0 and 1 that describes the shape of the concentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'concentricSlopeNearVmax' and 'isometricSlope', as shown in the figure.
eccentricCurviness	A dimensionless parameter between 0 and 1 that describes the shape of the eccentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'isometricSlope' and 'eccentricSlopeNearVmax', as shown in the figure.

Conditions

 1)  0 <= concentricSlopeAtVmax < 1
2a)  1 < isometricSlope
2b)  (maxEccentricVelocityForceMultiplier-1)/1 < isometricMaxSlope
 3)  0 <= eccentricSlopeAtVmax < (maxEccentricVelocityForceMultiplier-1)/1
 4)  1 < maxEccentricVelocityForceMultiplier
 5)  0 <= concentricCurviness <= 1
 6)  0 <= eccentricCurviness <= 1

Default Parameter Values

concentricSlopeAtVmax .................. 0.0
concentricSlopeNearVmax ................ 0.25
isometricSlope ......................... 5.0
eccentricSlopeAtVmax ................... 0.0
eccentricSlopeNearVmax ................. 0.15
maxEccentricVelocityForceMultiplier .... 1.4
concentricCurviness .................... 0.6
eccentricCurviness ..................... 0.9

Example

ForceVelocityCurve fvCurve(0.0, 0.25, 5.0, 0.0, 0.15, 1.4, 0.6, 0.9);
double falVal  = fvCurve.calcValue(1.0);
double dfalVal = fvCurve.calcDerivative(1.0, 1);

References

Lieber, R.L. (2010) Skeletal Muscle Structure, Function, and Plasticity: The Physiological Basis of Rehabilitiation, 3rd ed. Baltimore: Lippincott Williams & Wilkins.

Note that this object should be updated through the set methods provided. These set methods will take care of rebuilding the curve correctly. If you modify the properties directly, the curve will not be rebuilt, and upon calling a function like calcValue, calcDerivative, or printCurveToCSVFile, an exception will be thrown because the curve is out-of-date with its properties.

Author: Matt Millard

Constructor & Destructor Documentation

OpenSim::ForceVelocityCurve::ForceVelocityCurve ( )

The default constructor creates a force-velocity curve using the default property values and assigns a default name.

OpenSim::ForceVelocityCurve::ForceVelocityCurve	(	double	concentricSlopeAtVmax,
		double	concentricSlopeNearVmax,
		double	isometricSlope,
		double	eccentricSlopeAtVmax,
		double	eccentricSlopeNearVmax,
		double	maxEccentricVelocityForceMultiplier,
		double	concentricCurviness,
		double	eccentricCurviness
	)

Constructs a force-velocity curve using the provided parameters and assigns a default name.

Member Function Documentation

double OpenSim::ForceVelocityCurve::calcDerivative	(	double	normFiberVelocity,
		int	order
	)		const

Calculates the derivative of the force-velocity multiplier with respect to the normalized fiber velocity.

Parameters

normFiberVelocity	The normalized velocity of the muscle fiber.
order	The order of the derivative. Only values of 0, 1, and 2 are acceptable.

Returns: The derivative of the force-velocity curve with respect to the normalized fiber velocity.

double OpenSim::ForceVelocityCurve::calcValue ( const SimTK::Vector & x ) const

inlineoverridevirtual

Implement the generic OpenSim::Function interface.

Reimplemented from OpenSim::Function.

References OVERRIDE_11.

double OpenSim::ForceVelocityCurve::calcValue ( double normFiberVelocity ) const

Evaluates the force-velocity curve at a normalized fiber velocity of 'normFiberVelocity'.

void OpenSim::ForceVelocityCurve::ensureCurveUpToDate ( )

double OpenSim::ForceVelocityCurve::getConcentricCurviness ( ) const

Returns: A dimensionless parameter between 0 and 1 that describes the shape of the concentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'concentricSlopeNearVmax' and 'isometricSlope', as shown in the figure in the class description.

double OpenSim::ForceVelocityCurve::getConcentricSlopeAtVmax ( ) const

Returns: The slope of the force-velocity curve at a normalized velocity of -1, which is the minimum slope of the concentric side of the force-velocity curve.

double OpenSim::ForceVelocityCurve::getConcentricSlopeNearVmax ( ) const

Returns: The slope of the force-velocity curve near the maximum normalized concentric (shortening) contraction velocity (between approximately -0.8 and -1).

SimTK::Vec2 OpenSim::ForceVelocityCurve::getCurveDomain ( ) const

Returns a SimTK::Vec2 containing the lower (0th element) and upper (1st element) bounds on the domain of the curve.

Outside this domain, the curve is approximated using linear extrapolation.

Returns: The minimum and maximum value of the domain, x, of the curve y(x). Within this range, y(x) is a curve; outside this range, the function y(x) is a C2-continuous linear extrapolation.

double OpenSim::ForceVelocityCurve::getEccentricCurviness ( ) const

Returns: A dimensionless parameter between 0 and 1 that describes the shape of the eccentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'isometricSlope' and 'eccentricSlopeNearVmax', as shown in the figure in the class description.

double OpenSim::ForceVelocityCurve::getEccentricSlopeAtVmax ( ) const

Returns: The slope of the force-velocity curve at a normalized velocity of 1, which is the minimum slope of the eccentric side of the force-velocity curve.

double OpenSim::ForceVelocityCurve::getEccentricSlopeNearVmax ( ) const

Returns: The slope of the force-velocity curve near the maximum normalized eccentric (lengthening) contraction velocity (between approximately 0.8 and 1).

double OpenSim::ForceVelocityCurve::getIsometricSlope ( ) const

Returns: The slope of the force-velocity curve at a normalized velocity of 0, which is the maximum slope of the force-velocity curve.

double OpenSim::ForceVelocityCurve::getMaxEccentricVelocityForceMultiplier ( ) const

Returns: The value of the force-velocity curve (i.e., the force-velocity multiplier) at the maximum eccentric contraction velocity.

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	concentric_slope_at_vmax	,
		double	,
		"Curve slope at the maximum normalized concentric (shortening) velocity (normalized velocity of -1)"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	concentric_slope_near_vmax	,
		double	,
		"Curve slope just before reaching concentric_slope_at_vmax"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	isometric_slope	,
		double	,
		"Curve slope at isometric (normalized velocity of 0)"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	eccentric_slope_at_vmax	,
		double	,
		"Curve slope at the maximum normalized eccentric (lengthening) velocity (normalized velocity of 1)"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	eccentric_slope_near_vmax	,
		double	,
		"Curve slope just before reaching eccentric_slope_at_vmax"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	max_eccentric_velocity_force_multiplier	,
		double	,
		"Curve value at the maximum normalized eccentric contraction velocity"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	concentric_curviness	,
		double	,
		"Concentric curve	shape,
		from linear(0) to maximal curve(1)"
	)

OpenSim::ForceVelocityCurve::OpenSim_DECLARE_PROPERTY	(	eccentric_curviness	,
		double	,
		"Eccentric curve	shape,
		from linear(0) to maximal curve(1)"
	)

void OpenSim::ForceVelocityCurve::printMuscleCurveToCSVFile ( const std::string & path )

Generates a .csv file with a name that matches the curve name (e.g., "bicepsfemoris_ForceVelocityCurve.csv").

This function is not const to permit the curve to be rebuilt if it is out-of-date with its properties.

Parameters

path	The full destination path. Note that forward slashes ('/') must be used and there should not be a slash after the last folder.

The file will contain the following data:

column: 1 | 2 |     3 |       4
  data: x | y | dy/dx | d2y/dx2

Samples will be taken from the concentric linear extrapolation region (the region with normalized fiber velocities < -1), through the curve, out to the eccentric linear extrapolation region (the region with normalized fiber velocities > 1). The width of each linear extrapolation region is 10% of the curve domain, or 0.1*(x1-x0). The curve is sampled quite densely: the force-velocity .csv file will have 200+20 rows.

Example To read the .csv file into Matlab, you need to set csvread to ignore the header row. Since csvread is 0-indexed, the following example will begin reading the .csv file from the first column of the second row:

data = csvread('bicepsfemoris_ForceVelocityCurve.csv', 1, 0);

void OpenSim::ForceVelocityCurve::setConcentricCurviness ( double aConcentricCurviness )

Parameters

aConcentricCurviness A dimensionless parameter between 0 and 1 that describes the shape of the concentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'concentricSlopeNearVmax' and 'isometricSlope', as shown in the figure in the class description.

Conditions

0 <= concentricCurviness <= 1

void OpenSim::ForceVelocityCurve::setCurveShape	(	double	aConcentricSlopeAtVmax,
		double	aConcentricSlopeNearVmax,
		double	aIsometricSlope,
		double	aEccentricSlopeAtVmax,
		double	aEccentricSlopeNearVmax,
		double	aMaxForceMultiplier
	)

Parameters

aConcentricSlopeAtVmax	The slope of the force-velocity curve at a normalized velocity of -1, which is the minimum slope of the concentric side of the force-velocity curve.
aConcentricSlopeNearVmax	The slope of the force-velocity curve near the maximum normalized concentric (shortening) contraction velocity (between approximately -0.8 and -1).
aIsometricSlope	The slope of the force-velocity curve at a normalized velocity of 0, which is the maximum slope of the force-velocity curve.
aEccentricSlopeAtVmax	The slope of the force-velocity curve at a normalized velocity of 1, which is the minimum slope of the eccentric side of the force-velocity curve.
aEccentricSlopeNearVmax	The slope of the force-velocity curve near the maximum normalized eccentric (lengthening) contraction velocity (between approximately 0.8 and 1).
aMaxForceMultiplier	The value of the force-velocity curve (i.e., the force-velocity multiplier) at the maximum eccentric contraction velocity.

Conditions

1a)  0 <= concentricSlopeAtVmax < 1
1b)  concentricSlopeAtVmax < concentricSlopeNearVmax < 1
2a)  1 < isometricSlope
2b)  (maxEccentricVelocityForceMultiplier-1)/1 < isometricMaxSlope
3a)  0 <= eccentricSlopeAtVmax < (maxEccentricVelocityForceMultiplier-1)/1
3b)  eccentricSlopeAtVmax < eccentricSlopeNearVmax < (maxEccentricVelocityForceMultiplier-1)/1
 4)  1 < maxEccentricVelocityForceMultiplier

void OpenSim::ForceVelocityCurve::setEccentricCurviness ( double aEccentricCurviness )

Parameters

aEccentricCurviness A dimensionless parameter between 0 and 1 that describes the shape of the eccentric curve: a value of 0 indicates that the curve is very close to a straight line segment and a value of 1 indicates a curve that smoothly fills the corner formed by the linear extrapolation of 'isometricSlope' and 'eccentricSlopeNearVmax', as shown in the figure in the class description.

Conditions

0 <= eccentricCurviness <= 1

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

OpenSim/Actuators/ForceVelocityCurve.h

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation