Public Member Functions |
| | ActiveForceLengthCurve () |
| | The default constructor creates an active-force-length curve using the default property values and assigns a default name.
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| | ActiveForceLengthCurve (double minActiveNormFiberLength, double transitionNormFiberLength, double maxActiveNormFiberLength, double shallowAscendingSlope, double minimumValue) |
| | Constructs an active-force-length curve using the provided parameters and assigns a default name.
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| double | getMinActiveFiberLength () const |
| double | getTransitionFiberLength () const |
| double | getMaxActiveFiberLength () const |
| double | getShallowAscendingSlope () const |
| double | getMinValue () const |
| void | setActiveFiberLengths (double minActiveNormFiberLength, double transitionNormFiberLength, double maxActiveNormFiberLength, double shallowAscendingSlope) |
| void | setMinValue (double minimumValue) |
| double | calcValue (const SimTK::Vector &x) const override |
| | Implement the generic OpenSim::Function interface.
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| double | calcValue (double normFiberLength) const |
| | Evaluates the active-force-length curve at a normalized fiber length of 'normFiberLength'.
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| double | calcDerivative (double normFiberLength, int order) const |
| | Calculates the derivative of the active-force-length multiplier with respect to the normalized fiber length.
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| SimTK::Vec2 | getCurveDomain () const |
| | Returns a SimTK::Vec2 containing the lower (0th element) and upper (1st element) bounds on the domain of the curve.
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| void | printMuscleCurveToCSVFile (const std::string &path) |
| | Generates a .csv file with a name that matches the curve name (e.g., "bicepsfemoris_ActiveForceLengthCurve.csv").
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| void | ensureCurveUpToDate () |
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These are the serializable properties associated with this class.
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| | OpenSim_DECLARE_PROPERTY (min_norm_active_fiber_length, double,"Normalized fiber length where the steep ascending limb starts") |
| | OpenSim_DECLARE_PROPERTY (transition_norm_fiber_length, double,"Normalized fiber length where the steep ascending limb transitions to the shallow ascending limb") |
| | OpenSim_DECLARE_PROPERTY (max_norm_active_fiber_length, double,"Normalized fiber length where the descending limb ends") |
| | OpenSim_DECLARE_PROPERTY (shallow_ascending_slope, double,"Slope of the shallow ascending limb") |
| | OpenSim_DECLARE_PROPERTY (minimum_value, double,"Minimum value of the active-force-length curve") |
| | Function () |
| | Function (const Function &aFunction) |
| virtual | ~Function () |
| virtual void | init (Function *aFunction) |
| Function & | operator= (const Function &aFunction) |
| virtual double | calcDerivative (const std::vector< int > &derivComponents, const SimTK::Vector &x) const |
| | Calculate a partial derivative of this function at a particular point.
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| virtual int | getArgumentSize () const |
| | Get the number of components expected in the input vector.
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| virtual int | getMaxDerivativeOrder () const |
| | Get the maximum derivative order this Function object can calculate.
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| virtual SimTK::Function * | createSimTKFunction () const =0 |
| virtual | ~Object () |
| | Virtual destructor for cleanup.
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| virtual Object * | clone () const =0 |
| | Create a new heap-allocated copy of the concrete object to which this Object refers.
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| 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.
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| virtual const VisibleObject * | getDisplayer () const |
| | Methods to support making the object displayable in the GUI or Visualizer Implemented only in few objects.
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| virtual VisibleObject * | updDisplayer () |
| | get Non const pointer to VisibleObject
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| bool | isEqualTo (const Object &aObject) const |
| | Equality operator wrapper for use from languages not supporting operator overloading.
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| Object & | operator= (const Object &aObject) |
| | Copy assignment copies he base class fields, including the properties.
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| virtual bool | operator== (const Object &aObject) const |
| | Determine if two objects are equal.
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| virtual bool | operator< (const Object &aObject) const |
| | Provide an ordering for objects so they can be put in sorted containers.
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| void | setName (const std::string &name) |
| | Set the name of the Object.
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| const std::string & | getName () const |
| | Get the name of this Object.
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| void | setDescription (const std::string &description) |
| | Set description, a one-liner summary.
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| const std::string & | getDescription () const |
| | Get description, a one-liner summary.
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| const std::string & | getAuthors () const |
| | Get Authors of this Object.
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| void | setAuthors (const std::string &authors) |
| | Set Authors of this object, call this method in your constructor if needed.
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| const std::string & | getReferences () const |
| | Get references or publications to cite if using this object.
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| void | setReferences (const std::string &references) |
| | Set references or publications to cite if using this object.
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| int | getNumProperties () const |
| | Determine how many properties are stored with this Object.
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| const AbstractProperty & | getPropertyByIndex (int propertyIndex) const |
| | Get a const reference to a property by its index number, returned as an AbstractProperty.
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| AbstractProperty & | updPropertyByIndex (int propertyIndex) |
| | Get a writable reference to a property by its index number, returned as an AbstractProperty.
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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.
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| const AbstractProperty & | getPropertyByName (const std::string &name) const |
| | Get a const reference to a property by its name, returned as an AbstractProperty.
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| AbstractProperty & | updPropertyByName (const std::string &name) |
| | Get a writable reference to a property by its name, returned as an AbstractProperty.
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| 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.
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| 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.
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| 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.
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| 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.
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| bool | isObjectUpToDateWithProperties () const |
| | Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called.
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| void | readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber) |
| | We're given an XML element from which we are to populate this Object.
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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.
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| virtual void | updateXMLNode (SimTK::Xml::Element &parent) |
| | Serialize this object into the XML node that represents it.
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| bool | getInlined () const |
| | Inlined means an in-memory Object that is not associated with an XMLDocument.
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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.
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| std::string | getDocumentFileName () const |
| | If there is a document associated with this object then return the file name maintained by the document.
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| 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".
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| std::string | dump (bool dumpName=false) |
| | dump the XML representation of this Object into an std::string and return it.
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| void | clearObjectIsUpToDateWithProperties () |
| | For testing or debugging purposes, manually clear the "object is up to
date with respect to properties" flag.
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| 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.
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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.
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| PropertySet & | getPropertySet () |
| | OBSOLETE: Get a reference to the PropertySet maintained by the Object.
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| const PropertySet & | getPropertySet () const |
This class serves as a serializable ActiveForceLengthCurve, commonly used to model the active element in muscle models.
The active-force-length curve is dimensionless: force is normalized to maximum isometric force and length is normalized to resting fiber length. Five properties are used to construct a curve:
- Parameters
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| minActiveNormFiberLength | The normalized fiber length where the steep ascending limb of the active-force-length curve transitions to the minimum value and has first and second derivatives of 0. |
| transitionNormFiberLength | The normalized fiber length where the steep ascending limb transitions to the shallow ascending limb. |
| maxActiveNormFiberLength | The normalized fiber length where the descending limb transitions to the minimum value and has first and second derivatives of 0. |
| shallowAscendingSlope | The slope of the shallow ascending limb. |
| minimumValue | The minimum value of the active-force-length curve. If you are using an equilibrium model, this value must be greater than 0, as a value of 0 will cause a singularity in the muscle dynamic equations. |
Conditions
0 < minActiveNormFiberLength < transitionNormFiberLength < 1 < maxActiveNormFiberLength
0 <= shallowAscendingSlope < 1/(1-transitionNormFiberLength)
0 <= minimumValue
Default Parameter Values The default parameters have been chosen so that the resulting curve closely matches the active-force-length curve for human sarcomeres, as documented by Nigg and Herzog (1994). The descending limb has been adjusted to match the in-vitro human fiber data reported by Gollapudi and Lin (2009). The default shoulder value is set to 0.1. This relatively large value is used to ensure that muscle model dynamic equations with an active-force-length singularity do not take an unreasonable amount of time to simulate (simulation time grows as the value of the active-force-length curve approaches 0). Muscle model formulations that do not have this singularity (e.g., the Millard2012AccelerationMuscle model) can use a minimumValue of 0.
minActiveNormFiberLength ..... 0.4441
transitionNormFiberLength .... 0.73
maxActiveNormFiberLength ..... 1.8123
shallowAscendingSlope ........ 0.8616
minimumValue ................. 0.1
Example
double falVal = falCurve1.calcValue(1.0);
double dfalVal = falCurve1.calcDerivative(1.0, 1);
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.
References
- Gollapudi, S.K., Lin, D.C. (2009) Experimental determination of sarcomere force-length relationship in type-I human skeletal muscle fibers. Journal of Biomechanics 42(13), 2011–2016.
- Nigg, B.M., Herzog, W. Biomechanics of the Musculo-skeletal System. Wiley, 1994.
- Author
- Matt Millard
Public Member Functions inherited from OpenSim::Function
1.8.1.2