This is a muscle modeling utility class containing kinematic equations that describe the deformation of muscle fibers as they change length using a fixed-width-parallelogram pennation model. More...

#include <MuscleFixedWidthPennationModel.h>

Inheritance diagram for OpenSim::MuscleFixedWidthPennationModel:

Public Member Functions
	MuscleFixedWidthPennationModel ()
	The default constructor creates a fixed-width-parallelogram pennation model with the default property values. More...

	MuscleFixedWidthPennationModel (double optimalFiberLength, double optimalPennationAngle, double maximumPennationAngle)
	Creates a fixed-width-parallelogram pennation model using the provided parameters. More...

double	getParallelogramHeight () const

double	getOptimalFiberLength () const

double	getMinimumFiberLength () const

double	getMinimumFiberLengthAlongTendon () const

double	getOptimalPennationAngle () const

double	getMaximumPennationAngle () const

bool	setOptimalFiberLength (double aOptimalFiberLength)

bool	setOptimalPennationAngle (double aOptimalPennationAngle)

bool	setMaximumPennationAngle (double aMaximumPennationAngle)

double	clampFiberLength (double fiberLength) const
	Enforces a lower bound on the fiber length to avoid a numerical singularity as the fiber length approaches zero. More...

double	calcPennationAngle (double fiberLength) const
	Calculates the pennation angle (the orientation of the parallelogram) given the fiber length. More...

double	calcTendonLength (double cosPennationAngle, double fiberLength, double muscleLength) const
	Calculates the length of the tendon given the cosine of the pennation angle, the length of the fiber, and the length of the entire musculotendon actuator. More...

double	calcFiberLengthAlongTendon (double fiberLength, double cosPennationAngle) const
	Calculates the length of the fiber projected onto the axis of the tendon. More...

double	calcPennationAngularVelocity (double tanPennationAngle, double fiberLength, double fiberVelocity) const
	Calculates the angular velocity of the parallelogram (i.e., the time derivative of the pennation angle. More...

double	calcTendonVelocity (double cosPennationAngle, double sinPennationAngle, double pennationAngularVelocity, double fiberLength, double fiberVelocity, double muscleVelocity) const

double	calcFiberVelocityAlongTendon (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity) const

double	calcPennationAngularAcceleration (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity) const

double	calcFiberAccelerationAlongTendon (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double pennationAngularAcceleration) const

double	calc_DFiberLengthAlongTendon_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength) const
	Calculates the partial derivative of the fiber length along the tendon with respect to the fiber length. More...

double	calc_DPennationAngularVelocity_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength) const
	Calculates the partial derivative of the pennation angular velocity with respect to the fiber length. More...

double	calc_DFiberVelocityAlongTendon_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength, double DpennationAngularVelocity_DfiberLength) const
	Calculates the partial derivative of the fiber velocity along the tendon with respect to the fiber length. More...

double	calc_DPennationAngle_DfiberLength (double fiberLength) const
	Calculates the partial derivative of the pennation angle with respect to the fiber length. More...

double	calc_DTendonLength_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength) const
	Calculates the partial derivative of the tendon length with respect to the fiber length. More...

double	calcFiberLength (double muscleLength, double tendonLength) const

double	calcFiberVelocity (double cosPennationAngle, double muscleVelocity, double tendonVelocity) const

void	ensureModelUpToDate ()

Property declarations
These are the serializable properties associated with this class.
	OpenSim_DECLARE_PROPERTY (optimal_fiber_length, double,"Optimal length of the muscle fibers (meters)")

	OpenSim_DECLARE_PROPERTY (optimal_pennation_angle, double,"Angle between tendon and fibers at optimal fiber length (radians)")

	OpenSim_DECLARE_PROPERTY (maximum_pennation_angle, double,"Maximum pennation angle (radians)")

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::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::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::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 is a muscle modeling utility class containing kinematic equations that describe the deformation of muscle fibers as they change length using a fixed-width-parallelogram pennation model.

This pennation model makes several assumptions:

Fibers are straight, parallel, of equal length, and coplanar.
The area and height of the parallelogram remains constant.

The parallelogram maintains a constant area and height by shearing as the muscle fibers change length, as shown in the figure below. The constant-area assumption is intended to mimic the constant-volume property of incompressible biological muscle. For details, please refer to Zajac (1989) and Millard et al. (2013).

Parameters

optimalFiberLength	The optimal length of the muscle fibers (meters).
optimalPennationAngle	The angle between the tendon and fibers at optimal fiber length (radians).
maximumPennationAngle	The maximum pennation angle permitted (radians). This parameter is particularly useful for avoiding a pennation angle singularity at Pi/2 radians.

Conditions

optimalFiberLength > 0
0 <= optimalPennationAngle < Pi/2
0 <= maximumPennationAngle <= Pi/2

Default Parameter Values

optimalFiberLength ....... 0.1
optimalPennationAngle .... 0.0
maximumPennationAngle .... acos(0.1) = 84.3 degrees

Example

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.001);
MuscleFixedWidthPennationModel fibKin = MuscleFixedWidthPennationModel(optFibLen, optPenAng, maxPenAng);

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

References

Zajac, F.E. (1989) Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Critical Reviews in Biomedical Engineering 17(4):359–411.
Millard, M., Uchida, T., Seth, A., Delp, S.L. (2013) Flexing computational muscle: modeling and simulation of musculotendon dynamics. ASME Journal of Biomechanical Engineering 135(2):021005. http://dx.doi.org/10.1115/1.4023390.

Author: Matt Millard

Constructor & Destructor Documentation

OpenSim::MuscleFixedWidthPennationModel::MuscleFixedWidthPennationModel ( )

The default constructor creates a fixed-width-parallelogram pennation model with the default property values.

OpenSim::MuscleFixedWidthPennationModel::MuscleFixedWidthPennationModel	(	double	optimalFiberLength,
		double	optimalPennationAngle,
		double	maximumPennationAngle
	)

Creates a fixed-width-parallelogram pennation model using the provided parameters.

Member Function Documentation

double OpenSim::MuscleFixedWidthPennationModel::calc_DFiberLengthAlongTendon_DfiberLength	(	double	fiberLength,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	DpennationAngle_DfiberLength
	)		const

Calculates the partial derivative of the fiber length along the tendon with respect to the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calc_DFiberVelocityAlongTendon_DfiberLength	(	double	fiberLength,
		double	fiberVelocity,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity,
		double	DpennationAngle_DfiberLength,
		double	DpennationAngularVelocity_DfiberLength
	)		const

Calculates the partial derivative of the fiber velocity along the tendon with respect to the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calc_DPennationAngle_DfiberLength ( double fiberLength) const

Calculates the partial derivative of the pennation angle with respect to the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calc_DPennationAngularVelocity_DfiberLength	(	double	fiberLength,
		double	fiberVelocity,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity,
		double	DpennationAngle_DfiberLength
	)		const

Calculates the partial derivative of the pennation angular velocity with respect to the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calc_DTendonLength_DfiberLength	(	double	fiberLength,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	DpennationAngle_DfiberLength
	)		const

Calculates the partial derivative of the tendon length with respect to the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calcFiberAccelerationAlongTendon	(	double	fiberLength,
		double	fiberVelocity,
		double	fiberAcceleration,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity,
		double	pennationAngularAcceleration
	)		const

Parameters

fiberLength	The length of the fiber (m).
fiberVelocity	The lengthening velocity of the fiber (m/s).
fiberAcceleration	The lengthening acceleration of the fiber (m/s^2).
sinPennationAngle	The sine of the pennation angle.
cosPennationAngle	The cosine of the pennation angle.
pennationAngularVelocity	The angular velocity of the parallelogram (rad/s).
pennationAngularAcceleration	The angular acceleration of the parallelogram (rad/s^2).

Returns: The acceleration of the fiber projected onto the axis of the tendon (m/s^2).

double OpenSim::MuscleFixedWidthPennationModel::calcFiberLength	(	double	muscleLength,
		double	tendonLength
	)		const

Parameters

muscleLength	The length of the musculotendon actuator (m).
tendonLength	The length of the tendon (m).

Returns: The length of the fiber (m).

double OpenSim::MuscleFixedWidthPennationModel::calcFiberLengthAlongTendon	(	double	fiberLength,
		double	cosPennationAngle
	)		const

Calculates the length of the fiber projected onto the axis of the tendon.

double OpenSim::MuscleFixedWidthPennationModel::calcFiberVelocity	(	double	cosPennationAngle,
		double	muscleVelocity,
		double	tendonVelocity
	)		const

Parameters

cosPennationAngle	The cosine of the pennation angle.
muscleVelocity	The lengthening velocity of the musculotendon actuator (m/s).
tendonVelocity	The lengening velocity of the tendon (m/s).

Returns: The lengthening velocity of the fiber (m/s).

double OpenSim::MuscleFixedWidthPennationModel::calcFiberVelocityAlongTendon	(	double	fiberLength,
		double	fiberVelocity,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity
	)		const

Parameters

fiberLength	The length of the fiber (m).
fiberVelocity	The lengthening velocity of the fiber (m/s).
sinPennationAngle	The sine of the pennation angle.
cosPennationAngle	The cosine of the pennation angle.
pennationAngularVelocity	The angular velocity of the parallelogram (rad/s).

Returns: The lengthening velocity of the fiber projected onto the axis of the tendon (m/s).

double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngle ( double fiberLength) const

Calculates the pennation angle (the orientation of the parallelogram) given the fiber length.

double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngularAcceleration	(	double	fiberLength,
		double	fiberVelocity,
		double	fiberAcceleration,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity
	)		const

Parameters

fiberLength	The length of the fiber (m).
fiberVelocity	The lengthening velocity of the fiber (m/s).
fiberAcceleration	The lengthening acceleration of the fiber (m/s^2).
sinPennationAngle	The sine of the pennation angle.
cosPennationAngle	The cosine of the pennation angle.
pennationAngularVelocity	The angular velocity of the parallelogram (rad/s).

Returns: The angular acceleration of the parallelogram (rad/s^2).

double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngularVelocity	(	double	tanPennationAngle,
		double	fiberLength,
		double	fiberVelocity
	)		const

Calculates the angular velocity of the parallelogram (i.e., the time derivative of the pennation angle.

Parameters

tanPennationAngle	The tangent of the pennation angle.
fiberLength	The length of the fiber (m).
fiberVelocity	The lengthening velocity of the fiber (m/s).

Returns: The angular velocity of the parallelogram (rad/s).

double OpenSim::MuscleFixedWidthPennationModel::calcTendonLength	(	double	cosPennationAngle,
		double	fiberLength,
		double	muscleLength
	)		const

Calculates the length of the tendon given the cosine of the pennation angle, the length of the fiber, and the length of the entire musculotendon actuator.

double OpenSim::MuscleFixedWidthPennationModel::calcTendonVelocity	(	double	cosPennationAngle,
		double	sinPennationAngle,
		double	pennationAngularVelocity,
		double	fiberLength,
		double	fiberVelocity,
		double	muscleVelocity
	)		const

Parameters

cosPennationAngle	The cosine of the pennation angle.
sinPennationAngle	The sine of the pennation angle.
pennationAngularVelocity	The angular velocity of the parallelogram (rad/s).
fiberLength	The length of the fiber (m).
fiberVelocity	The lengthening velocity of the fiber (m/s).
muscleVelocity	The lengthening velocity of the muscle path (m/s).

Returns: The lengthening velocity of the tendon (m/s).

double OpenSim::MuscleFixedWidthPennationModel::clampFiberLength ( double fiberLength) const

Enforces a lower bound on the fiber length to avoid a numerical singularity as the fiber length approaches zero.

void OpenSim::MuscleFixedWidthPennationModel::ensureModelUpToDate ( )

double OpenSim::MuscleFixedWidthPennationModel::getMaximumPennationAngle ( ) const

Returns: The maximum permissible pennation angle.

double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLength ( ) const

Returns: The minimum possible fiber length.

double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLengthAlongTendon ( ) const

Returns: The minimum possible fiber length along the tendon.

double OpenSim::MuscleFixedWidthPennationModel::getOptimalFiberLength ( ) const

Returns: The optimal fiber length.

double OpenSim::MuscleFixedWidthPennationModel::getOptimalPennationAngle ( ) const

Returns: The optimal pennation angle (radians).

double OpenSim::MuscleFixedWidthPennationModel::getParallelogramHeight ( ) const

Returns: The height of the fixed-width paralleogram.

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	optimal_fiber_length	,
		double	,
		"Optimal length of the muscle fibers (meters)"
	)

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	optimal_pennation_angle	,
		double	,
		"Angle between tendon and fibers at optimal fiber length (radians)"
	)

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	maximum_pennation_angle	,
		double	,
		"Maximum pennation angle (radians)"
	)

bool OpenSim::MuscleFixedWidthPennationModel::setMaximumPennationAngle ( double aMaximumPennationAngle)

bool OpenSim::MuscleFixedWidthPennationModel::setOptimalFiberLength ( double aOptimalFiberLength)

bool OpenSim::MuscleFixedWidthPennationModel::setOptimalPennationAngle ( double aOptimalPennationAngle)

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

/home/fitze/repos/opensim/Branches/OpenSim32ForDoxygen/OpenSim/Actuators/MuscleFixedWidthPennationModel.h

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