This is a class that acts as a utility class that contains all of the necessary kinematic equations required to use a fixed width parallelogram pennation model to compute the way the muscle fibers deform as the muscle contracts. More...

#include <MuscleFixedWidthPennationModel.h>

Inheritance diagram for OpenSim::MuscleFixedWidthPennationModel:

Public Member Functions
	MuscleFixedWidthPennationModel (double optimalFiberLength, double optimalPennationAngle, double maximumPennationAngle, std::string &caller)
	MuscleFixedWidthPennationModel ()
	Default constructor.
bool	setOptimalPennationAngle (double aOptimalPennationAngle)
bool	setOptimalFiberLength (double aOptimalFiberLength)
bool	setMaximumPennationAngle (double aMaximumPennationAngle)
double	getMaximumPennationAngle () const
double	getMinimumFiberLength () const
double	getMinimumFiberLengthAlongTendon () const
double	clampFiberLength (double fiberLength) const
	This function will clamp fiberLength within 0.001*optimalFiberLengths of the minimum fiber length at which singularities occur.
double	getParallelogramHeight () const
double	getOptimalFiberLength () const
double	getOptimalPennationAngle () const
double	calcFiberLengthAlongTendon (double fiberLength, double cosPennationAngle) const
double	calc_DFiberLengthAlongTendon_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength) const
double	calcFiberVelocityAlongTendon (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity) const
double	calc_DFiberVelocityAlongTendon_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength, double DpennationAngularVelocity_DfiberLength) const
double	calc_DPennationAngularVelocity_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength, std::string &caller) const
double	calcPennationAngle (double fiberLength) const
	This function calculates the pennation angle of the fiber given its current length.
double	calcPennationAngularVelocity (double tanPennationAngle, double fiberLength, double fiberVelocity, std::string &caller) const
	This function computes the angular velocity of the fiber.
double	calcPennationAngularAcceleration (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, std::string &caller) const
double	calcFiberAccelerationAlongTendon (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double pennationAngularAcceleration) const
double	calcTendonLength (double cosPennationAngle, double fiberLength, double muscleLength) const
	This function computes the length of the tendon given the length of the muscle, the length of the fiber, and the current pennation angle.
double	calcTendonVelocity (double cosPennationAngle, double sinPennationAngle, double pennationAngularVelocity, double fiberLength, double fiberVelocity, double muscleVelocity) const
	This function computes the lengthening velocity (or stretch velocity) of the tendon.
double	calc_DPennationAngle_DfiberLength (double fiberLength, std::string &caller) const
	The partial derivative of the pennation angle with respect to fiber length.
double	calc_DTendonLength_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength, std::string &caller) const
	The partial derivative of tendon length with respect to fiber length.
double	calcFiberLength (double muscleLength, double tendonLength) const
double	calcFiberVelocity (double fiberLength, double sinPennationAngle, double cosPennationAngle, double muscleLength, double tendonLength, double muscleVelocity, double tendonVelocity, std::string &caller) const
Property declarations
These are the serializable properties associated with this class.
	OpenSim_DECLARE_PROPERTY (optimal_fiber_length, double,"optimal or resting fiber length in units of meters")
	OpenSim_DECLARE_PROPERTY (optimal_pennation_angle, double,"pennation angle in radians of a fiber at its optimal length")
	OpenSim_DECLARE_PROPERTY (maximum_pennation_angle, double,"maximum pennation angle in radians")
Public Member Functions inherited from OpenSim::Object
virtual	~Object ()
	Virtual destructor for cleanup.
virtual Object *	clone () const =0
	Create a new heap-allocated copy of the concrete object to which this Object refers.
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.
virtual const VisibleObject *	getDisplayer () const
	Methods to support making the object displayable in the GUI or Visualizer Implemented only in few objects.
virtual VisibleObject *	updDisplayer ()
	get Non const pointer to VisibleObject
bool	isEqualTo (const Object &aObject) const
	Equality operator wrapper for use from languages not supporting operator overloading.
Object &	operator= (const Object &aObject)
	Copy assignment copies he base class fields, including the properties.
virtual bool	operator== (const Object &aObject) const
	Determine if two objects are equal.
virtual bool	operator< (const Object &aObject) const
	Provide an ordering for objects so they can be put in sorted containers.
void	setName (const std::string &name)
	Set the name of the Object.
const std::string &	getName () const
	Get the name of this Object.
void	setDescription (const std::string &description)
	Set description, a one-liner summary.
const std::string &	getDescription () const
	Get description, a one-liner summary.
const std::string &	getAuthors () const
	Get Authors of this Object.
void	setAuthors (const std::string &authors)
	Set Authors of this object, call this method in your constructor if needed.
const std::string &	getReferences () const
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void	setReferences (const std::string &references)
	Set references or publications to cite if using this object.
int	getNumProperties () const
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const AbstractProperty &	getPropertyByIndex (int propertyIndex) const
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AbstractProperty &	updPropertyByIndex (int propertyIndex)
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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.
const AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty.
AbstractProperty &	updPropertyByName (const std::string &name)
	Get a writable reference to a property by its name, returned as an AbstractProperty.
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.
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.
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.
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.
bool	isObjectUpToDateWithProperties () const
	Returns \c true if any property's value has changed since the last time setObjectIsUpToDateWithProperties() was called.
void	readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
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virtual void	updateFromXMLNode (SimTK::Xml::Element &objectElement, int versionNumber)
	Use this method to deserialize an object from a SimTK::Xml::Element.
virtual void	updateXMLNode (SimTK::Xml::Element &parent)
	Serialize this object into the XML node that represents it.
bool	getInlined () const
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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.
std::string	getDocumentFileName () const
	If there is a document associated with this object then return the file name maintained by the document.
void	setAllPropertiesUseDefault (bool aUseDefault)
bool	print (const std::string &fileName)
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std::string	dump (bool dumpName=false)
	dump the XML representation of this Object into an std::string and return it.
void	clearObjectIsUpToDateWithProperties ()
	For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag.
virtual bool	isA (const char *type) const
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const std::string &	toString () const
	Wrapper to be used on Java side to display objects in tree; this returns just the object's name.
PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object.
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.
static void	renameType (const std::string &oldTypeName, const std::string &newTypeName)
	Support versioning by associating the current %Object type with an old name.
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.
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*.
static Object *	newInstanceOfType (const std::string &concreteClassName)
	Create a new instance of the concrete %Object type whose class name is given as concreteClassName.
static void	getRegisteredTypenames (Array< std::string > &typeNames)
	Retrieve all the typenames registered so far.
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.
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.
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.
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.
static const std::string &	getClassName ()
	Return the name of this class as a string; i.e., "Object".
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.
static bool	getSerializeAllDefaults ()
	Report the value of the "serialize all defaults" flag.
static bool	isKindOf (const char *type)
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static void	setDebugLevel (int newLevel)
	Set the debug level to get verbose output.
static int	getDebugLevel ()
	Get current setting of debug level.
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.
static void	RegisterType (const Object &defaultObject)
	OBSOLETE alternate name for registerType().
static void	RenameType (const std::string &oldName, const std::string &newName)
	OBSOLETE alternate name for renameType().
Static Public Attributes inherited from OpenSim::Object
static const std::string	DEFAULT_NAME
	Name used for default objects when they are serialized.
Protected Member Functions inherited from OpenSim::Object
	Object ()
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	Object (const std::string &fileName, bool aUpdateFromXMLNode=true) SWIG_DECLARE_EXCEPTION
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	Object (const Object &source)
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	Object (SimTK::Xml::Element &aElement)
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template<class T >
PropertyIndex	addProperty (const std::string &name, const std::string &comment, const T &value)
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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.
template<class T >
PropertyIndex	addOptionalProperty (const std::string &name, const std::string &comment, const T &value)
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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.
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)
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PropertyIndex	getPropertyIndex (const std::string &name) const
	Look up a property by name and return its PropertyIndex if it is found.
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.
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.
void	setDocument (XMLDocument *doc)
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const XMLDocument *	getDocument () const
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XMLDocument *	updDocument ()
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Protected Attributes inherited from OpenSim::Object
PropertySet	_propertySet
	OBSOLETE: Property_Deprecated set for serializable member variables of this and derived classes.
Related Functions inherited from OpenSim::Object
#define	OpenSim_DECLARE_CONCRETE_OBJECT(ConcreteClass, SuperClass)
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#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.
#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>.
#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.

Detailed Description

This is a class that acts as a utility class that contains all of the necessary kinematic equations required to use a fixed width parallelogram pennation model to compute the way the muscle fibers deform as the muscle contracts.

A fixed width parallelogram pennation model makes a number of assumptions:

The width of the parallelogram stays constant
The area of the parallelogram stays constant.
Fibers are all parallel, and of the same length

The parallelogram pennation model achieves a constant area by permitting the parallelogram to shear while maintaining a constant height. The constant area property is intended to mimic the constant volume property of muscle, which arises because muscle is incompressible for all practial purposes.

This class has been coded to eliminate duplicate calculations. Thus if a function depends on pennationAngle, or cos(pennationAngle), it will request this quantity rather than re-compute this value itself.

ASSUMPTIONS

1) This pennation model is compatible with muscle models that assume that the effect of the pennation of the fiber on the transmission of force from the fiber to the tendon is multiplicative. That is

fiberForceAlongTendon = fiberForce * f()

Where 'f()' is the function that relates the pennation of the fibers to how much force is transmitted from the fiber to the tendon.

2) This pennation model assumes that fiber length, and whole muscle length are known.

Author: Matt Millard

Version: 0.0

Constructor & Destructor Documentation

OpenSim::MuscleFixedWidthPennationModel::MuscleFixedWidthPennationModel	(	double	optimalFiberLength,
		double	optimalPennationAngle,
		double	maximumPennationAngle,
		std::string &	caller
	)

Parameters

optimalFiberLength	The length of the fiber (meters) at its optimal length
optimalPennationAngle	The angle of the fiber (radians) when it is at its optimal angle
maximumPennationAngle	The maximum pennation angle permitted. This is particularly useful to set for muscle models that have a pennation singularity. For those muscles that do not, this parameter must be greater than SimTK::Pi/2, as a pennation angle of Pi/2 will cause a singularity in several of the internal functions of this class.
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Constructs a ParallelogramPennationModel object, which dictates how the movement of the fiber affects its orientation, and how force is transferred from the fiber to the tendon.

Conditions:

    0 <  optimalFiberLength
    0 <= optimalPennationAngle < SimTK::Pi/2
    0 <= maximumPennationAngle < SimTK::Pi/2

Example:

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

Computational Costs

_______________________________________________________________________
                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                    1        2               1

OpenSim::MuscleFixedWidthPennationModel::MuscleFixedWidthPennationModel ( )

Default constructor.

Populates member data with NaN's and other obviously wrong values

Member Function Documentation

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

Parameters

fiberLength	The length of the fiber (meters)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
DpennationAngle_DfiberLength	The partial derivative of the pennation angle with respect to fiber length

Returns: the partial derivative of the fiber length along the tendon with respect to small changes in 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

Parameters

fiberLength	The length of the fiber (meters)
fiberVelocity	The stretch velocity of the fiber (meters/s)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
pennationAngularVelocity	The angular velocity of the pennation angle.
DpennationAngle_DfiberLength	The partial derivative of the pennation angle with respect to fiber length
DpennationAngularVelocity_DfiberLength	The partial derivative of the pennation angular velocity w.r.t. fiber length

Returns: the partial derivative of the fiber velocity along the tendon with respect to a change in fiber length

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.1);
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, maxPenAng, caller);
double fibLen = optFibLen*2;
double penAng = fibKin.calcPennationAngle(fibLen);
double fibVel = 0.2;
double penAngVel = fibKin.calcPennationAngularVelocity(
                        tan(penAng), fibLen,fibVel,caller);
double Dphi_Dlce = fibKin.calc_DPennationAngle_DfiberLength(fibLen,
                                                            caller);
double DdlceAT_Dlce=
    fibKin.calc_DFiberVelocityAlongTendon_DfiberLength(fibLen,
                                                       fibVel,
                                                       sin(penAng),
                                                       cos(penAng),
                                                       penAngVel,
                                                       Dphi_Dlce,
                                                       caller);

Computational Costs

_______________________________________________________________________
                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                     0       2       3       14      6         10

double OpenSim::MuscleFixedWidthPennationModel::calc_DPennationAngle_DfiberLength	(	double	fiberLength,
		std::string &	caller
	)		const

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

Parameters

fiberLength	The length of the fiber (meters)
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Returns: the partial derivative of fiber angle w.r.t. fiber length (rad/m)

Conditions:

    parallelogramHeight < fiberLength

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.1);
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, maxPenAng, caller);
    
double fibLen = optFibLen*2;
double DphiDlce = fibKin.calc_DPennationAngle_DfiberLength(fibLen, 
                                                            caller);

Computational Costs

_______________________________________________________________________
                    Sqrt     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                    1        2       2       5       1       5

double OpenSim::MuscleFixedWidthPennationModel::calc_DPennationAngularVelocity_DfiberLength	(	double	fiberLength,
		double	fiberVelocity,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity,
		double	DpennationAngle_DfiberLength,
		std::string &	caller
	)		const

Parameters

fiberLength	The length of the fiber (meters)
fiberVelocity	The stretch velocity of the fiber (meters/s)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
pennationAngularVelocity	The angular velocity of the pennation angle.
DpennationAngle_DfiberLength	The partial derivative of the pennation angle with respect to fiber length
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Returns: the partial derivative of the pennation angular velocity with respect to changes in fiber length

Conditions:

    0 <  fiberLength 
    pennationAngle < 90 degrees

double OpenSim::MuscleFixedWidthPennationModel::calc_DTendonLength_DfiberLength	(	double	fiberLength,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	DpennationAngle_DfiberLength,
		std::string &	caller
	)		const

The partial derivative of tendon length with respect to fiber length.

Parameters

fiberLength	The length of the fiber (meters)
sinPennationAngle	The sin(pennationAngle)
cosPennationAngle	The cos(pennationAngle)
DpennationAngle_DfiberLength	The partial derivative of pennation angle w.r.t. fiber length (rad/m)
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Returns: the partial derivative of tendon length w.r.t. fiber length in (m/m).

Conditions:

    0 <  fiberLength
    parallelogramHeight < fiberLength

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.1);
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, maxPenAng, caller);
double fibLen = optFibLen*2;
double penAng = fibKin.calcPennationAngle(fibLen);
double DphiDlce = fibKin.calc_DPennationAngle_DfiberLength(fibLen, 
                                                            caller);
double DtdnDlce = fibKin.calc_DTendonLength_DfiberLength(fibLen,
                            sin(penAng), cos(penAng),DphiDlce,caller);

Computational Costs

_______________________________________________________________________
                            Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                            2               2       1       1

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 (meters)
fiberVelocity	The stretch velocity of the fiber (meters/s)
fiberAcceleration	The stretch acceleration of the fiber (meters/s^2)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
pennationAngularVelocity	The angular velocity of the pennation angle.
pennationAngularAcceleration	the angular acceleration of the pennation angle (rad/s^2)

Returns: the acceleration of the fiber in the direction of the tendon

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

Parameters

muscleLength	the length of the musculo tendon (meters)
tendonLength	the length of the tendon (meters

Returns: the fiber length (meters)

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

Parameters

fiberLength	The length of the fiber (meters)
cosPennationAngle	The cosine of the pennation angle (unitless)

Returns: The projected length of the fiber along the tendon axis

double OpenSim::MuscleFixedWidthPennationModel::calcFiberVelocity	(	double	fiberLength,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	muscleLength,
		double	tendonLength,
		double	muscleVelocity,
		double	tendonVelocity,
		std::string &	caller
	)		const

Parameters

fiberLength	The length of the fiber (meters)
sinPennationAngle	The sin(pennationAngle)
cosPennationAngle	The cos(pennationAngle)
muscleLength	The length of the muscle (meters)
tendonLength	The length of the tendon (meters)
muscleVelocity	The lengthening velocity of the muscle (meters/s)
tendonVelocity	The lengening velocity of the tendon (meters/s)
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Returns: the lengthening velocity of the fiber (meters/s)

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

Parameters

fiberLength	The length of the fiber (meters)
fiberVelocity	The stretch velocity of the fiber (meters/s)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
pennationAngularVelocity	The angular velocity of the pennation angle.

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

This function calculates the pennation angle of the fiber given its current length.

The pennation angle is saturated at SimTK::Pi/2 for fiber lengths that are less than, or equal to, the minimum physical fiber length for this pennation model.

Parameters

fiberLength the length of the fiber (meters)

Returns: the current pennation angle (radians)

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng);
double fibLen = optFibLen*2;
double penAng = fibKin.calcPennationAngle(fibLen,caller);

Computational Costs

_______________________________________________________________________
                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                    1        2       1       1               2

double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngularAcceleration	(	double	fiberLength,
		double	fiberVelocity,
		double	fiberAcceleration,
		double	sinPennationAngle,
		double	cosPennationAngle,
		double	pennationAngularVelocity,
		std::string &	caller
	)		const

Parameters

fiberLength	The length of the fiber (meters)
fiberVelocity	The stretch velocity of the fiber (meters/s)
fiberAcceleration	The stretch acceleration of the fiber (meters/s^2)
sinPennationAngle	The sine of the pennation angle (unitless)
cosPennationAngle	The cosine of the pennation angle (unitless)
pennationAngularVelocity	The angular velocity of the pennation angle.
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

Returns: the angular acceleration of the pennation angle (rad/s^2)

double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngularVelocity	(	double	tanPennationAngle,
		double	fiberLength,
		double	fiberVelocity,
		std::string &	caller
	)		const

This function computes the angular velocity of the fiber.

Parameters

tanPennationAngle	The result of tan(pennationAngle)
fiberLength	The length of the fiber (meters)
fiberVelocity	The lengthening/shortening velocity of the fiber in (meters/sec)
caller	The name of the function calling this one. This string is used to help the user debug their model when an assertion fails.

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

Conditions:

    0 <  fiberLength

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, caller);
double fibLen = optFibLen*2;           
double penAng = fibKin.calcPennationAngle(fibLen);
double fibVel = optFibLen*3/1.0; //3 fiber lengths / second
//See constructor example to create fibKin
double penAngVel = fibKin.calcPennationAngularVelocity(
                                tan(penAng),fibLen,fibVel,caller);

Computational Costs

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                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                                1      1       1               1

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

This function computes the length of the tendon given the length of the muscle, the length of the fiber, and the current pennation angle.

Parameters

cosPennationAngle	The cosine of the current pennation angle
fiberLength	The length of the fiber (meters)
muscleLength	The length of the whole muscle (meters)

Returns: length of the tendon (meters)

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, caller);
double fibLen = optFibLen*2;
double penAng = fibKin.calcPennationAngle(fibLen);
double mclLen = optFibLen*3;
double tdnLen = fibKin.calcTendonLength(cos(penAng),fibLen, mclLen);

Computational Costs

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                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                                                1       1        1

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

This function computes the lengthening velocity (or stretch velocity) of the tendon.

Parameters

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

Returns: the rate of tendon stretching (m/s)

Example:

double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.1);
string caller = "yourFunctionNameHere";
MuscleFixedWidthPennationModel fibKin = 
                    MuscleFixedWidthPennationModel(
                        optFibLen, optPenAng, maxPenAng, caller);
double fibLen = optFibLen*2;            
double penAng = fibKin.calcPennationAngle(fibLen);
double fibVel = optFibLen*3/1.0; //3 fiber lengths / second
double penAngVel = fibKin.calcPennationAngularVelocity(
                        tan(penAng),fibLen,caller);
double mclLen = optFibLen*3;
double mclVel = optFibLen*4/1.0; //4 fiber lengths/sec
    
double tdnVel = fibKin.calcTendonVelocity(cos(penAng),sin(penAng),
                                    penAngVel,fibLen,fibVel,mclVel);

Computational Costs

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                    Trig     Comp.   Div.    Mult.   Add.    Assign.
_______________________________________________________________________
                                                3       2        1

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

This function will clamp fiberLength within 0.001*optimalFiberLengths of the minimum fiber length at which singularities occur.

Parameters

fiberLength is the length of the fiber in meters

double OpenSim::MuscleFixedWidthPennationModel::getMaximumPennationAngle ( ) const

Returns: the maximum pennation angle allowed

double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLength ( ) const

Returns: the minimum fiber length. For this pennation model the minimum numerically stable fiber length is parallelogram_height plus 0.001*optimalFiberLength

double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLengthAlongTendon ( ) const

Returns: the minimum fiber length along the tendon. For this pennation model the minimum numerically stable fiber length is parallelogram_height plus 0.001*optimalFiberLength

double OpenSim::MuscleFixedWidthPennationModel::getOptimalFiberLength ( ) const

Returns: optimal fiber length (m)

double OpenSim::MuscleFixedWidthPennationModel::getOptimalPennationAngle ( ) const

Returns: the optimal pennation angle (radians)

double OpenSim::MuscleFixedWidthPennationModel::getParallelogramHeight ( ) const

Returns: height of the paralleogram (m)

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	optimal_fiber_length	,
		double	,
		"optimal or resting fiber length in units of meters"
	)

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	optimal_pennation_angle	,
		double	,
		"pennation angle in radians of a fiber at its optimal length"
	)

OpenSim::MuscleFixedWidthPennationModel::OpenSim_DECLARE_PROPERTY	(	maximum_pennation_angle	,
		double	,
		"maximum pennation angle in 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:

E:/Projects/OpenSim30Br/OpenSim30/OpenSim/Actuators/MuscleFixedWidthPennationModel.h

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