API  4.3
For MATLAB, Python, Java, and C++ users
OpenSim::ForceVelocityCurve Class Reference

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

+ Inheritance diagram for OpenSim::ForceVelocityCurve:

OpenSim Properties, Sockets, Outputs, Inputs

Properties (single-value)
double concentric_slope_at_vmax
 "Curve slope at the maximum normalized concentric (shortening) velocity (normalized velocity of -1)" More...
 
double concentric_slope_near_vmax
 "Curve slope just before reaching concentric_slope_at_vmax" More...
 
double isometric_slope
 "Curve slope at isometric (normalized velocity of 0)" More...
 
double eccentric_slope_at_vmax
 "Curve slope at the maximum normalized eccentric (lengthening) velocity (normalized velocity of 1)" More...
 
double eccentric_slope_near_vmax
 "Curve slope just before reaching eccentric_slope_at_vmax" More...
 
double max_eccentric_velocity_force_multiplier
 "Curve value at the maximum normalized eccentric contraction velocity" More...
 
double concentric_curviness
 "Concentric curve shape, from linear (0) to maximal curve (1)" More...
 
double eccentric_curviness
 "Eccentric curve shape, from linear (0) to maximal curve (1)" More...
 

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)
 
More...
 
void setConcentricCurviness (double aConcentricCurviness)
 
More...
 
void setEccentricCurviness (double aEccentricCurviness)
 
More...
 
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...
 
double calcDerivative (const std::vector< int > &derivComponents, const SimTK::Vector &x) const override
 If possible, use the simpler overload above. 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-related functions
const double & get_concentric_slope_at_vmax () const
 Get the value of the concentric_slope_at_vmax property. More...
 
double & upd_concentric_slope_at_vmax ()
 Get a writable reference to the concentric_slope_at_vmax property. More...
 
void set_concentric_slope_at_vmax (const double &value)
 Set the value of the concentric_slope_at_vmax property. More...
 
const double & get_concentric_slope_near_vmax () const
 Get the value of the concentric_slope_near_vmax property. More...
 
double & upd_concentric_slope_near_vmax ()
 Get a writable reference to the concentric_slope_near_vmax property. More...
 
void set_concentric_slope_near_vmax (const double &value)
 Set the value of the concentric_slope_near_vmax property. More...
 
const double & get_isometric_slope () const
 Get the value of the isometric_slope property. More...
 
double & upd_isometric_slope ()
 Get a writable reference to the isometric_slope property. More...
 
void set_isometric_slope (const double &value)
 Set the value of the isometric_slope property. More...
 
const double & get_eccentric_slope_at_vmax () const
 Get the value of the eccentric_slope_at_vmax property. More...
 
double & upd_eccentric_slope_at_vmax ()
 Get a writable reference to the eccentric_slope_at_vmax property. More...
 
void set_eccentric_slope_at_vmax (const double &value)
 Set the value of the eccentric_slope_at_vmax property. More...
 
const double & get_eccentric_slope_near_vmax () const
 Get the value of the eccentric_slope_near_vmax property. More...
 
double & upd_eccentric_slope_near_vmax ()
 Get a writable reference to the eccentric_slope_near_vmax property. More...
 
void set_eccentric_slope_near_vmax (const double &value)
 Set the value of the eccentric_slope_near_vmax property. More...
 
const double & get_max_eccentric_velocity_force_multiplier () const
 Get the value of the max_eccentric_velocity_force_multiplier property. More...
 
double & upd_max_eccentric_velocity_force_multiplier ()
 Get a writable reference to the max_eccentric_velocity_force_multiplier property. More...
 
void set_max_eccentric_velocity_force_multiplier (const double &value)
 Set the value of the max_eccentric_velocity_force_multiplier property. More...
 
const double & get_concentric_curviness () const
 Get the value of the concentric_curviness property. More...
 
double & upd_concentric_curviness ()
 Get a writable reference to the concentric_curviness property. More...
 
void set_concentric_curviness (const double &value)
 Set the value of the concentric_curviness property. More...
 
const double & get_eccentric_curviness () const
 Get the value of the eccentric_curviness property. More...
 
double & upd_eccentric_curviness ()
 Get a writable reference to the eccentric_curviness property. More...
 
void set_eccentric_curviness (const double &value)
 Set the value of the eccentric_curviness property. More...
 
- Public Member Functions inherited from OpenSim::Function
 Function ()
 
 Function (const Function &aFunction)
 
virtual ~Function ()
 
virtual void init (Function *aFunction)
 
Functionoperator= (const Function &aFunction)
 
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...
 
bool isEqualTo (const Object &aObject) const
 Equality operator wrapper for use from languages not supporting operator overloading. More...
 
Objectoperator= (const Object &aObject)
 Copy assignment copies he base class fields, including the properties. More...
 
virtual bool operator== (const Object &aObject) const
 Determine if two objects are equal. More...
 
virtual bool operator< (const Object &aObject) const
 Provide an ordering for objects so they can be put in sorted containers. More...
 
void setName (const std::string &name)
 Set the name of the Object. More...
 
const std::string & getName () const
 Get the name of this Object. More...
 
void setDescription (const std::string &description)
 Set description, a one-liner summary. More...
 
const std::string & getDescription () const
 Get description, a one-liner summary. More...
 
const std::string & getAuthors () const
 Get Authors of this Object. More...
 
void setAuthors (const std::string &authors)
 Set Authors of this object. More...
 
const std::string & getReferences () const
 Get references or publications to cite if using this object. More...
 
void setReferences (const std::string &references)
 Set references or publications to cite if using this object. More...
 
int getNumProperties () const
 Determine how many properties are stored with this Object. More...
 
const AbstractPropertygetPropertyByIndex (int propertyIndex) const
 Get a const reference to a property by its index number, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByIndex (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 AbstractPropertygetPropertyByName (const std::string &name) const
 Get a const reference to a property by its name, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByName (const std::string &name)
 Get a writable reference to a property by its name, returned as an AbstractProperty. More...
 
template<class T >
bool hasProperty () const
 Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...
 
template<class T >
const Property< T > & getProperty (const PropertyIndex &index) const
 Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...
 
template<class T >
Property< T > & updProperty (const PropertyIndex &index)
 Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...
 
bool isObjectUpToDateWithProperties () const
 Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...
 
void readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
 We're given an XML element from which we are to populate this Object. More...
 
virtual void updateFromXMLNode (SimTK::Xml::Element &objectElement, int versionNumber)
 Use this method to deserialize an object from a SimTK::Xml::Element. More...
 
void updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
 Serialize this object into the XML node that represents it. More...
 
bool getInlined () const
 Inlined means an in-memory Object that is not associated with an XMLDocument. More...
 
void setInlined (bool aInlined, const std::string &aFileName="")
 Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...
 
std::string getDocumentFileName () const
 If there is a document associated with this object then return the file name maintained by the document. More...
 
int getDocumentFileVersion () const
 If there is a document associated with this object then return its version number. More...
 
void setAllPropertiesUseDefault (bool aUseDefault)
 
bool print (const std::string &fileName) const
 Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...
 
std::string dump () const
 dump the XML representation of this Object into an std::string and return it. More...
 
virtual bool isA (const char *type) const
 The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...
 
const std::string & toString () const
 Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...
 
PropertySetgetPropertySet ()
 OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...
 
const PropertySetgetPropertySet () const
 

Auto-generated functions

static ForceVelocityCurvesafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
static const std::string & getClassName ()
 This returns "ForceVelocityCurve". More...
 
ForceVelocityCurveclone () const override
 Create a new heap-allocated copy of the concrete object to which this Object refers. More...
 
const std::string & getConcreteClassName () const override
 Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from OpenSim::Function
static FunctionmakeFunctionOfType (Function *aFunction, const std::string &aNewTypeName)
 
static FunctionsafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
static const std::string & getClassName ()
 This returns "Function". More...
 
- Static Public Member Functions inherited from OpenSim::Object
static void registerType (const Object &defaultObject)
 Register an instance of a class; if the class is already registered it will be replaced. More...
 
static void renameType (const std::string &oldTypeName, const std::string &newTypeName)
 Support versioning by associating the current Object type with an old name. More...
 
static const ObjectgetDefaultInstanceOfType (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 ObjectnewInstanceOfType (const std::string &concreteClassName)
 Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...
 
static void getRegisteredTypenames (Array< std::string > &typeNames)
 Retrieve all the typenames registered so far. More...
 
template<class T >
static void getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
 Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
 Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
 Same as the other signature but the class name and property name are provided as two separate strings. More...
 
static ObjectmakeObjectFromFile (const std::string &fileName)
 Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...
 
static const std::string & getClassName ()
 Return the name of this class as a string; i.e., "Object". More...
 
static void setSerializeAllDefaults (bool shouldSerializeDefaults)
 Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...
 
static bool getSerializeAllDefaults ()
 Report the value of the "serialize all defaults" flag. More...
 
static bool isKindOf (const char *type)
 Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...
 
static void setDebugLevel (int newLevel)
 Set the amount of logging output. More...
 
static int getDebugLevel ()
 Get the current setting of debug level. More...
 
static ObjectSafeCopy (const Object *aObject)
 Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...
 
static void RegisterType (const Object &defaultObject)
 OBSOLETE alternate name for registerType(). More...
 
static void RenameType (const std::string &oldName, const std::string &newName)
 OBSOLETE alternate name for renameType(). More...
 

Detailed Description

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
concentricSlopeAtVmaxThe 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 parameter is 0, though values greater than 0 are necessary when the force-velocity curve must be inverted.
concentricSlopeNearVmaxThe slope of the force-velocity curve near the maximum normalized concentric (shortening) contraction velocity (between approximately -0.8 and -1).
isometricSlopeThe 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 Lieber, 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.
eccentricSlopeAtVmaxThe 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.
eccentricSlopeNearVmaxThe slope of the force-velocity curve near the maximum normalized eccentric (lengthening) contraction velocity (between approximately 0.8 and 1).
maxEccentricVelocityForceMultiplierThe value of the force-velocity curve (i.e., the force-velocity multiplier) at the maximum eccentric contraction velocity. Physiologically accurate values for this parameter range between 1.1 and 1.8, and may vary between subjects.
concentricCurvinessA 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.
eccentricCurvinessA 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.
fig_ForceVelocityCurve.png

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 Rehabilitation, 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

◆ ForceVelocityCurve() [1/2]

OpenSim::ForceVelocityCurve::ForceVelocityCurve ( )

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

◆ ForceVelocityCurve() [2/2]

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

◆ calcDerivative() [1/2]

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
normFiberVelocityThe normalized velocity of the muscle fiber.
orderThe 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.

◆ calcDerivative() [2/2]

double OpenSim::ForceVelocityCurve::calcDerivative ( const std::vector< int > &  derivComponents,
const SimTK::Vector &  x 
) const
overridevirtual

If possible, use the simpler overload above.

Reimplemented from OpenSim::Function.

◆ calcValue() [1/2]

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

Implement the generic OpenSim::Function interface.

Reimplemented from OpenSim::Function.

◆ calcValue() [2/2]

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

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

◆ clone()

ForceVelocityCurve* OpenSim::ForceVelocityCurve::clone ( ) const
inlineoverridevirtual

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

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

Implements OpenSim::Function.

◆ ensureCurveUpToDate()

void OpenSim::ForceVelocityCurve::ensureCurveUpToDate ( )

◆ get_concentric_curviness()

const double& OpenSim::ForceVelocityCurve::get_concentric_curviness ( ) const
inline

Get the value of the concentric_curviness property.

◆ get_concentric_slope_at_vmax()

const double& OpenSim::ForceVelocityCurve::get_concentric_slope_at_vmax ( ) const
inline

Get the value of the concentric_slope_at_vmax property.

◆ get_concentric_slope_near_vmax()

const double& OpenSim::ForceVelocityCurve::get_concentric_slope_near_vmax ( ) const
inline

Get the value of the concentric_slope_near_vmax property.

◆ get_eccentric_curviness()

const double& OpenSim::ForceVelocityCurve::get_eccentric_curviness ( ) const
inline

Get the value of the eccentric_curviness property.

◆ get_eccentric_slope_at_vmax()

const double& OpenSim::ForceVelocityCurve::get_eccentric_slope_at_vmax ( ) const
inline

Get the value of the eccentric_slope_at_vmax property.

◆ get_eccentric_slope_near_vmax()

const double& OpenSim::ForceVelocityCurve::get_eccentric_slope_near_vmax ( ) const
inline

Get the value of the eccentric_slope_near_vmax property.

◆ get_isometric_slope()

const double& OpenSim::ForceVelocityCurve::get_isometric_slope ( ) const
inline

Get the value of the isometric_slope property.

◆ get_max_eccentric_velocity_force_multiplier()

const double& OpenSim::ForceVelocityCurve::get_max_eccentric_velocity_force_multiplier ( ) const
inline

Get the value of the max_eccentric_velocity_force_multiplier property.

◆ getClassName()

static const std::string& OpenSim::ForceVelocityCurve::getClassName ( )
inlinestatic

This returns "ForceVelocityCurve".

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

◆ getConcentricCurviness()

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.

◆ getConcentricSlopeAtVmax()

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.

◆ getConcentricSlopeNearVmax()

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).

◆ getConcreteClassName()

const std::string& OpenSim::ForceVelocityCurve::getConcreteClassName ( ) const
inlineoverridevirtual

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

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

See also
getClassName()

Implements OpenSim::Function.

◆ getCurveDomain()

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.

◆ getEccentricCurviness()

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.

◆ getEccentricSlopeAtVmax()

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.

◆ getEccentricSlopeNearVmax()

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).

◆ getIsometricSlope()

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.

◆ getMaxEccentricVelocityForceMultiplier()

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.

◆ printMuscleCurveToCSVFile()

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
pathThe 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);

◆ safeDownCast()

static ForceVelocityCurve* OpenSim::ForceVelocityCurve::safeDownCast ( OpenSim::Object obj)
inlinestatic

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

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

◆ set_concentric_curviness()

void OpenSim::ForceVelocityCurve::set_concentric_curviness ( const double &  value)
inline

Set the value of the concentric_curviness property.

◆ set_concentric_slope_at_vmax()

void OpenSim::ForceVelocityCurve::set_concentric_slope_at_vmax ( const double &  value)
inline

Set the value of the concentric_slope_at_vmax property.

◆ set_concentric_slope_near_vmax()

void OpenSim::ForceVelocityCurve::set_concentric_slope_near_vmax ( const double &  value)
inline

Set the value of the concentric_slope_near_vmax property.

◆ set_eccentric_curviness()

void OpenSim::ForceVelocityCurve::set_eccentric_curviness ( const double &  value)
inline

Set the value of the eccentric_curviness property.

◆ set_eccentric_slope_at_vmax()

void OpenSim::ForceVelocityCurve::set_eccentric_slope_at_vmax ( const double &  value)
inline

Set the value of the eccentric_slope_at_vmax property.

◆ set_eccentric_slope_near_vmax()

void OpenSim::ForceVelocityCurve::set_eccentric_slope_near_vmax ( const double &  value)
inline

Set the value of the eccentric_slope_near_vmax property.

◆ set_isometric_slope()

void OpenSim::ForceVelocityCurve::set_isometric_slope ( const double &  value)
inline

Set the value of the isometric_slope property.

◆ set_max_eccentric_velocity_force_multiplier()

void OpenSim::ForceVelocityCurve::set_max_eccentric_velocity_force_multiplier ( const double &  value)
inline

Set the value of the max_eccentric_velocity_force_multiplier property.

◆ setConcentricCurviness()

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


Parameters
aConcentricCurvinessA 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

◆ setCurveShape()

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


Parameters
aConcentricSlopeAtVmaxThe 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.
aConcentricSlopeNearVmaxThe slope of the force-velocity curve near the maximum normalized concentric (shortening) contraction velocity (between approximately -0.8 and -1).
aIsometricSlopeThe slope of the force-velocity curve at a normalized velocity of 0, which is the maximum slope of the force-velocity curve.
aEccentricSlopeAtVmaxThe 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.
aEccentricSlopeNearVmaxThe slope of the force-velocity curve near the maximum normalized eccentric (lengthening) contraction velocity (between approximately 0.8 and 1).
aMaxForceMultiplierThe 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

◆ setEccentricCurviness()

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


Parameters
aEccentricCurvinessA 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

◆ upd_concentric_curviness()

double& OpenSim::ForceVelocityCurve::upd_concentric_curviness ( )
inline

Get a writable reference to the concentric_curviness property.

◆ upd_concentric_slope_at_vmax()

double& OpenSim::ForceVelocityCurve::upd_concentric_slope_at_vmax ( )
inline

Get a writable reference to the concentric_slope_at_vmax property.

◆ upd_concentric_slope_near_vmax()

double& OpenSim::ForceVelocityCurve::upd_concentric_slope_near_vmax ( )
inline

Get a writable reference to the concentric_slope_near_vmax property.

◆ upd_eccentric_curviness()

double& OpenSim::ForceVelocityCurve::upd_eccentric_curviness ( )
inline

Get a writable reference to the eccentric_curviness property.

◆ upd_eccentric_slope_at_vmax()

double& OpenSim::ForceVelocityCurve::upd_eccentric_slope_at_vmax ( )
inline

Get a writable reference to the eccentric_slope_at_vmax property.

◆ upd_eccentric_slope_near_vmax()

double& OpenSim::ForceVelocityCurve::upd_eccentric_slope_near_vmax ( )
inline

Get a writable reference to the eccentric_slope_near_vmax property.

◆ upd_isometric_slope()

double& OpenSim::ForceVelocityCurve::upd_isometric_slope ( )
inline

Get a writable reference to the isometric_slope property.

◆ upd_max_eccentric_velocity_force_multiplier()

double& OpenSim::ForceVelocityCurve::upd_max_eccentric_velocity_force_multiplier ( )
inline

Get a writable reference to the max_eccentric_velocity_force_multiplier property.

OpenSim Property, Socket, Output, Input Documentation

◆ concentric_curviness

double OpenSim::ForceVelocityCurve::concentric_curviness

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

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

See also
get_concentric_curviness(), upd_concentric_curviness(), set_concentric_curviness()

◆ concentric_slope_at_vmax

double OpenSim::ForceVelocityCurve::concentric_slope_at_vmax

"Curve slope at the maximum normalized concentric (shortening) velocity (normalized velocity of -1)"

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

See also
get_concentric_slope_at_vmax(), upd_concentric_slope_at_vmax(), set_concentric_slope_at_vmax()

◆ concentric_slope_near_vmax

double OpenSim::ForceVelocityCurve::concentric_slope_near_vmax

"Curve slope just before reaching concentric_slope_at_vmax"

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

See also
get_concentric_slope_near_vmax(), upd_concentric_slope_near_vmax(), set_concentric_slope_near_vmax()

◆ eccentric_curviness

double OpenSim::ForceVelocityCurve::eccentric_curviness

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

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

See also
get_eccentric_curviness(), upd_eccentric_curviness(), set_eccentric_curviness()

◆ eccentric_slope_at_vmax

double OpenSim::ForceVelocityCurve::eccentric_slope_at_vmax

"Curve slope at the maximum normalized eccentric (lengthening) velocity (normalized velocity of 1)"

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

See also
get_eccentric_slope_at_vmax(), upd_eccentric_slope_at_vmax(), set_eccentric_slope_at_vmax()

◆ eccentric_slope_near_vmax

double OpenSim::ForceVelocityCurve::eccentric_slope_near_vmax

"Curve slope just before reaching eccentric_slope_at_vmax"

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

See also
get_eccentric_slope_near_vmax(), upd_eccentric_slope_near_vmax(), set_eccentric_slope_near_vmax()

◆ isometric_slope

double OpenSim::ForceVelocityCurve::isometric_slope

"Curve slope at isometric (normalized velocity of 0)"

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

See also
get_isometric_slope(), upd_isometric_slope(), set_isometric_slope()

◆ max_eccentric_velocity_force_multiplier

double OpenSim::ForceVelocityCurve::max_eccentric_velocity_force_multiplier

"Curve value at the maximum normalized eccentric contraction velocity"

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

See also
get_max_eccentric_velocity_force_multiplier(), upd_max_eccentric_velocity_force_multiplier(), set_max_eccentric_velocity_force_multiplier()

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