This is a muscle modeling utility class containing kinematic equations that describe the deformation of muscle fibers as they change length using a fixed-width-parallelogram pennation model.
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Public Member Functions |
| | MuscleFixedWidthPennationModel () |
| | The default constructor creates a fixed-width-parallelogram pennation model with the default property values.
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| | MuscleFixedWidthPennationModel (double optimalFiberLength, double optimalPennationAngle, double maximumPennationAngle) |
| | Creates a fixed-width-parallelogram pennation model using the provided parameters.
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| double | getParallelogramHeight () const |
| double | getOptimalFiberLength () const |
| double | getMinimumFiberLength () const |
| double | getMinimumFiberLengthAlongTendon () const |
| double | getOptimalPennationAngle () const |
| double | getMaximumPennationAngle () const |
| bool | setOptimalFiberLength (double aOptimalFiberLength) |
| bool | setOptimalPennationAngle (double aOptimalPennationAngle) |
| bool | setMaximumPennationAngle (double aMaximumPennationAngle) |
| double | clampFiberLength (double fiberLength) const |
| | Enforces a lower bound on the fiber length to avoid a numerical singularity as the fiber length approaches zero.
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| double | calcPennationAngle (double fiberLength) const |
| | Calculates the pennation angle (the orientation of the parallelogram) given the fiber length.
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| double | calcTendonLength (double cosPennationAngle, double fiberLength, double muscleLength) const |
| | Calculates the length of the tendon given the cosine of the pennation angle, the length of the fiber, and the length of the entire musculotendon actuator.
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| double | calcFiberLengthAlongTendon (double fiberLength, double cosPennationAngle) const |
| | Calculates the length of the fiber projected onto the axis of the tendon.
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| double | calcPennationAngularVelocity (double tanPennationAngle, double fiberLength, double fiberVelocity) const |
| | Calculates the angular velocity of the parallelogram (i.e., the time derivative of the pennation angle.
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| double | calcTendonVelocity (double cosPennationAngle, double sinPennationAngle, double pennationAngularVelocity, double fiberLength, double fiberVelocity, double muscleVelocity) const |
| double | calcFiberVelocityAlongTendon (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity) const |
| double | calcPennationAngularAcceleration (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity) const |
| double | calcFiberAccelerationAlongTendon (double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double pennationAngularAcceleration) const |
| double | calc_DFiberLengthAlongTendon_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength) const |
| | Calculates the partial derivative of the fiber length along the tendon with respect to the fiber length.
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| double | calc_DPennationAngularVelocity_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength) const |
| | Calculates the partial derivative of the pennation angular velocity with respect to the fiber length.
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| double | calc_DFiberVelocityAlongTendon_DfiberLength (double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double DpennationAngle_DfiberLength, double DpennationAngularVelocity_DfiberLength) const |
| | Calculates the partial derivative of the fiber velocity along the tendon with respect to the fiber length.
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| double | calc_DPennationAngle_DfiberLength (double fiberLength) const |
| | Calculates the partial derivative of the pennation angle with respect to the fiber length.
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| double | calc_DTendonLength_DfiberLength (double fiberLength, double sinPennationAngle, double cosPennationAngle, double DpennationAngle_DfiberLength) const |
| | Calculates the partial derivative of the tendon length with respect to the fiber length.
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| double | calcFiberLength (double muscleLength, double tendonLength) const |
| double | calcFiberVelocity (double cosPennationAngle, double muscleVelocity, double tendonVelocity) const |
| void | ensureModelUpToDate () |
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These are the serializable properties associated with this class.
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| | OpenSim_DECLARE_PROPERTY (optimal_fiber_length, double,"Optimal length of the muscle fibers (meters)") |
| | OpenSim_DECLARE_PROPERTY (optimal_pennation_angle, double,"Angle between tendon and fibers at optimal fiber length (radians)") |
| | OpenSim_DECLARE_PROPERTY (maximum_pennation_angle, double,"Maximum pennation angle (radians)") |
| 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 |
Additional Inherited Members |
| static void | registerType (const Object &defaultObject) |
| | Register an instance of a class; if the class is already registered it will be replaced.
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| static void | renameType (const std::string &oldTypeName, const std::string &newTypeName) |
| | Support versioning by associating the current Object type with an old name.
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| 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.
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| 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*.
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| static Object * | newInstanceOfType (const std::string &concreteClassName) |
| | Create a new instance of the concrete Object type whose class name is given as concreteClassName.
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| static void | getRegisteredTypenames (Array< std::string > &typeNames) |
| | Retrieve all the typenames registered so far.
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| 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.
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| 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.
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| 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.
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| 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.
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| static const std::string & | getClassName () |
| | Return the name of this class as a string; i.e., "Object".
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| 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.
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| static bool | getSerializeAllDefaults () |
| | Report the value of the "serialize all defaults" flag.
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| 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.
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| static void | setDebugLevel (int newLevel) |
| | Set the debug level to get verbose output.
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| static int | getDebugLevel () |
| | Get current setting of debug level.
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| 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.
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| static void | RegisterType (const Object &defaultObject) |
| | OBSOLETE alternate name for registerType().
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| static void | RenameType (const std::string &oldName, const std::string &newName) |
| | OBSOLETE alternate name for renameType().
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| static const std::string | DEFAULT_NAME |
| | Name used for default objects when they are serialized.
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| | Object () |
| | The default constructor is only for use by constructors of derived types.
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| | Object (const std::string &fileName, bool aUpdateFromXMLNode=true) SWIG_DECLARE_EXCEPTION |
| | Constructor from a file, to be called from other constructors that take a file as input.
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| | Object (const Object &source) |
| | Copy constructor is invoked automatically by derived classes with default copy constructors; otherwise it must be invoked explicitly.
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| | Object (SimTK::Xml::Element &aElement) |
| | Construct the base class portion of an Object from a given Xml element that describes this Object.
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| template<class T > |
| PropertyIndex | addProperty (const std::string &name, const std::string &comment, const T &value) |
| | Define a new single-value property of known type T, with the given name, associated comment, and initial value.
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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.
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| template<class T > |
| PropertyIndex | addOptionalProperty (const std::string &name, const std::string &comment, const T &value) |
| | Add an optional property, meaning it can contain either no value or a single value.
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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.
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| template<class T , template< class > class Container> |
| PropertyIndex | addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize, const Container< T > &valueList) |
| | Define a new list-valued property as above, but assigning an initial value via some templatized container class that supports size() and indexing.
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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.
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| 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.
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| 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.
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| void | setDocument (XMLDocument *doc) |
| | Unconditionally set the XMLDocument associated with this object.
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| const XMLDocument * | getDocument () const |
| | Get a const pointer to the document (if any) associated with this object.
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| XMLDocument * | updDocument () |
| | Get a writable pointer to the document (if any) associated with this object.
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| PropertySet | _propertySet |
| | OBSOLETE: Property_Deprecated set for serializable member variables of this and derived classes.
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| #define | OpenSim_DECLARE_CONCRETE_OBJECT(ConcreteClass, SuperClass) |
| | Macro to be included as the first line of the class declaration for any non-templatized, concrete class that derives from OpenSim::Object.
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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.
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| #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>.
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| #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.
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This is a muscle modeling utility class containing kinematic equations that describe the deformation of muscle fibers as they change length using a fixed-width-parallelogram pennation model.
This pennation model makes several assumptions:
- Fibers are straight, parallel, of equal length, and coplanar.
- The area and height of the parallelogram remains constant.
The parallelogram maintains a constant area and height by shearing as the muscle fibers change length, as shown in the figure below. The constant-area assumption is intended to mimic the constant-volume property of incompressible biological muscle. For details, please refer to Zajac (1989) and Millard et al. (2013).
- Parameters
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| optimalFiberLength | The optimal length of the muscle fibers (meters). |
| optimalPennationAngle | The angle between the tendon and fibers at optimal fiber length (radians). |
| maximumPennationAngle | The maximum pennation angle permitted (radians). This parameter is particularly useful for avoiding a pennation angle singularity at Pi/2 radians. |
Conditions
optimalFiberLength > 0
0 <= optimalPennationAngle < Pi/2
0 <= maximumPennationAngle <= Pi/2
Default Parameter Values
optimalFiberLength ....... 0.1
optimalPennationAngle .... 0.0
maximumPennationAngle .... acos(0.1) = 84.3 degrees
Example
double optFibLen = 0.1;
double optPenAng = SimTK::Pi/4.0;
double maxPenAng = acos(0.001);
Note that this object should be updated through the set methods provided. These set methods will take care of rebuilding the object correctly. If you modify the properties directly, the object will not be rebuilt, and upon calling any function, an exception will be thrown because the object is out-of-date with its properties.
References
- Zajac, F.E. (1989) Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Critical Reviews in Biomedical Engineering 17(4):359–411.
- Millard, M., Uchida, T., Seth, A., Delp, S.L. (2013) Flexing computational muscle: modeling and simulation of musculotendon dynamics. ASME Journal of Biomechanical Engineering 135(2):021005. http://dx.doi.org/10.1115/1.4023390.
- Author
- Matt Millard
Public Member Functions inherited from OpenSim::Object
1.8.1.2 
