API  4.1 For C++ developers
OpenSim::MuscleFixedWidthPennationModel Class Reference

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

Inheritance diagram for OpenSim::MuscleFixedWidthPennationModel:

## OpenSim Properties, Sockets, Outputs, Inputs

Properties (single-value)
double optimal_fiber_length
"Optimal length of the muscle fibers, in meters (overridden when this is a subcomponent of a Muscle)" More...

double pennation_angle_at_optimal
"Angle between tendon and fibers at optimal fiber length, in radians (overridden when this is a subcomponent of a Muscle)" More...

double maximum_pennation_angle
"Maximum pennation angle, in radians (overridden when this is a subcomponent of a Muscle)" More...

OpenSim Properties, Sockets, Outputs, Inputs inherited from OpenSim::Component
Component components
"List of components that this component owns and serializes." More...

## Public Member Functions

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

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

double getParallelogramHeight () const

double getMinimumFiberLength () const

double getMinimumFiberLengthAlongTendon () const

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

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

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

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

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

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

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

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

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

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

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

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

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

double calcFiberLength (double muscleLength, double tendonLength) const

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

Property-related functions
const double & get_optimal_fiber_length () const
Get the value of the optimal_fiber_length property. More...

double & upd_optimal_fiber_length ()
Get a writable reference to the optimal_fiber_length property. More...

void set_optimal_fiber_length (const double &value)
Set the value of the optimal_fiber_length property. More...

const double & get_pennation_angle_at_optimal () const
Get the value of the pennation_angle_at_optimal property. More...

double & upd_pennation_angle_at_optimal ()
Get a writable reference to the pennation_angle_at_optimal property. More...

void set_pennation_angle_at_optimal (const double &value)
Set the value of the pennation_angle_at_optimal property. More...

const double & get_maximum_pennation_angle () const
Get the value of the maximum_pennation_angle property. More...

double & upd_maximum_pennation_angle ()
Get a writable reference to the maximum_pennation_angle property. More...

void set_maximum_pennation_angle (const double &value)
Set the value of the maximum_pennation_angle property. More...

Public Member Functions inherited from OpenSim::ModelComponent
ModelComponent ()
Default constructor. More...

ModelComponent (const std::string &aFileName, bool aUpdateFromXMLNode=true)
Construct ModelComponent from an XML file. More...

ModelComponent (SimTK::Xml::Element &aNode)
Construct ModelComponent from a specific node in an XML document. More...

virtual ~ModelComponent ()
Destructor is virtual to allow concrete model component cleanup. More...

void connectToModel (Model &model)
Connect this ModelComponent to its aggregate- a Model. More...

const ModelgetModel () const
Get a const reference to the Model this component is part of. More...

ModelupdModel ()
Get a modifiable reference to the Model this component is part of. More...

bool hasModel () const
Does this ModelComponent have a Model associated with it? More...

void preScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...

void scale (const SimTK::State &s, const ScaleSet &scaleSet)
Scale the ModelComponent. More...

void postScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

Public Member Functions inherited from OpenSim::Component
Component ()
Default constructor. More...

Component (const std::string &aFileName, bool aUpdateFromXMLNode=true)
Construct Component from an XML file. More...

Component (SimTK::Xml::Element &aNode)
Construct Component from a specific node in an XML document. More...

Component (const Component &)=default
Use default copy constructor and assignment operator. More...

Componentoperator= (const Component &)=default

virtual ~Component ()=default
Destructor is virtual to allow concrete Component to cleanup. More...

virtual void generateDecorations (bool fixed, const ModelDisplayHints &hints, const SimTK::State &state, SimTK::Array_< SimTK::DecorativeGeometry > &appendToThis) const
Optional method for generating arbitrary display geometry that reflects this Component at the specified state. More...

const SimTK::MultibodySystem & getSystem () const
Get the underlying MultibodySystem that this component is connected to. More...

bool hasSystem () const
Check if this component has an underlying MultibodySystem. More...

bool isComponentInOwnershipTree (const Component *component) const
Does the provided component already exist anywhere in the ownership tree (not just subcomponents of this component)? More...

Add a Component (as a subcomponent) of this component. More...

template<typename T = Component>
ComponentList< const T > getComponentList () const
Get an iterator through the underlying subcomponents that this component is composed of. More...

template<typename T = Component>
ComponentList< T > updComponentList ()
Similar to getComponentList(), except the resulting list allows one to modify the components. More...

template<typename T = Component>
unsigned countNumComponents () const
Uses getComponentList<T>() to count the number of underlying subcomponents of the specified type. More...

std::string getAbsolutePathString () const
Get the complete (absolute) pathname for this Component to its ancestral Component, which is the root of the tree to which this Component belongs. More...

ComponentPath getAbsolutePath () const
Return a ComponentPath of the absolute path of this Component. More...

std::string getRelativePathString (const Component &wrt) const
Get the relative path of this Component with respect to another Component, as a string. More...

ComponentPath getRelativePath (const Component &wrt) const
Get the relative path of this Component with respect to another Component. More...

bool hasComponent (const std::string &pathname) const
Query if there is a component (of any type) at the specified path name. More...

template<class C = Component>
bool hasComponent (const std::string &pathname) const
Query if there is a component of a given type at the specified path name. More...

template<class C = Component>
const C & getComponent (const std::string &pathname) const
Get a unique subcomponent of this Component by its path name and type 'C'. More...

template<class C = Component>
const C & getComponent (const ComponentPath &pathname) const

const ComponentgetComponent (const std::string &pathname) const
Similar to the templatized getComponent(), except this returns the component as the generic Component type. More...

template<class C = Component>
C & updComponent (const std::string &name)
Get a writable reference to a subcomponent. More...

template<class C = Component>
C & updComponent (const ComponentPath &name)

ComponentupdComponent (const std::string &pathname)
Similar to the templatized updComponent(), except this returns the component as the generic Component type. More...

unsigned printComponentsMatching (const std::string &substring) const
Print a list to the console of all components whose absolute path name contains the given string. More...

int getNumStateVariables () const
Get the number of "continuous" state variables maintained by the Component and its subcomponents. More...

Array< std::string > getStateVariableNames () const
Get the names of "continuous" state variables maintained by the Component and its subcomponents. More...

template<class C = Component>
const C * findComponent (const ComponentPath &pathToFind) const
Find a Component to which this Component is an ancestor—in other words, a Component that is directly owned by this Component or is owned by one of its sub-components, sub-sub-components, etc. More...

template<class C = Component>
const C * findComponent (const std::string &pathToFind) const
Same as findComponent(const ComponentPath&), but accepting a string (a path or just a name) as input. More...

const StateVariabletraverseToStateVariable (const std::string &pathName) const
Get a StateVariable anywhere in the Component tree, given a StateVariable path. More...

void finalizeFromProperties ()
Define a Component's internal data members and structure according to its properties. More...

void finalizeConnections (Component &root)
Satisfy the Component's connections specified by its Sockets and Inputs. More...

void clearConnections ()
Disconnect/clear this Component from its aggregate component. More...

Have the Component add itself to the underlying computational System. More...

void initStateFromProperties (SimTK::State &state) const
Initialize Component's state variable values from its properties. More...

void setPropertiesFromState (const SimTK::State &state)
Set Component's properties given a state. More...

int getNumSockets () const
Get the number of Sockets in this Component. More...

std::vector< std::string > getSocketNames ()
Collect and return the names of the sockets in this component. More...

template<typename T >
const T & getConnectee (const std::string &name) const
Get the "connectee" object that the Component's Socket is bound to. More...

const ObjectgetConnectee (const std::string &name) const
Get the connectee as an Object. More...

const AbstractSocketgetSocket (const std::string &name) const
Get an AbstractSocket for the given socket name. More...

AbstractSocketupdSocket (const std::string &name)
Get a writable reference to the AbstractSocket for the given socket name. More...

template<typename T >
const Socket< T > & getSocket (const std::string &name) const
Get a const reference to the concrete Socket provided by this Component by name. More...

template<typename T >
Socket< T > & updSocket (const std::string &name)
Get a writable reference to the concrete Socket provided by this Component by name. More...

int getModelingOption (const SimTK::State &state, const std::string &name) const
Get a ModelingOption flag for this Component by name. More...

void setModelingOption (SimTK::State &state, const std::string &name, int flag) const
Set the value of a ModelingOption flag for this Component. More...

template<typename T >
const T & getInputValue (const SimTK::State &state, const std::string &name) const
Get the Input value that this component is dependent on. More...

template<typename T >
const T & getOutputValue (const SimTK::State &state, const std::string &name) const
Get the Output value provided by this Component by name. More...

double getStateVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a state variable allocated by this Component. More...

void setStateVariableValue (SimTK::State &state, const std::string &name, double value) const
Set the value of a state variable allocated by this Component by name. More...

SimTK::Vector getStateVariableValues (const SimTK::State &state) const
Get all values of the state variables allocated by this Component. More...

void setStateVariableValues (SimTK::State &state, const SimTK::Vector &values) const
Set all values of the state variables allocated by this Component. More...

double getStateVariableDerivativeValue (const SimTK::State &state, const std::string &name) const
Get the value of a state variable derivative computed by this Component. More...

double getDiscreteVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a discrete variable allocated by this Component by name. More...

void setDiscreteVariableValue (SimTK::State &state, const std::string &name, double value) const
Set the value of a discrete variable allocated by this Component by name. More...

template<typename T >
const T & getCacheVariableValue (const SimTK::State &state, const std::string &name) const
Get the value of a cache variable allocated by this Component by name. More...

template<typename T >
T & updCacheVariableValue (const SimTK::State &state, const std::string &name) const
Obtain a writable cache variable value allocated by this Component by name. More...

void markCacheVariableValid (const SimTK::State &state, const std::string &name) const
After updating a cache variable value allocated by this Component, you can mark its value as valid, which will not change until the realization stage falls below the minimum set at the time the cache variable was created. More...

void markCacheVariableInvalid (const SimTK::State &state, const std::string &name) const
Mark a cache variable value allocated by this Component as invalid. More...

bool isCacheVariableValid (const SimTK::State &state, const std::string &name) const
Enables the user to monitor the validity of the cache variable value using the returned flag. More...

template<typename T >
void setCacheVariableValue (const SimTK::State &state, const std::string &name, const T &value) const
Set cache variable value allocated by this Component by name. More...

void printSubcomponentInfo () const
List all subcomponents by name and recurse into these components to list their subcomponents, and so on. More...

void printSocketInfo () const
List all the Sockets of this component and whether or not they are connected. More...

void printInputInfo () const
List all the inputs of this component and whether or not they are connected. More...

template<typename C >
void printSubcomponentInfo () const

void printOutputInfo (const bool includeDescendants=true) const
Print outputs of this component and optionally, those of all subcomponents. More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

int getNumInputs () const
Access the number of Inputs that this component has. More...

int getNumOutputs () const
Access the number of Outputs that this component has. More...

std::vector< std::string > getInputNames () const
Collect and return the names of Inputs in this component as an std::vector. More...

std::vector< std::string > getOutputNames () const
Collect and return the names of Outputs in this component as an std::vector. More...

const AbstractInputgetInput (const std::string &name) const
Get an Input provided by this Component by name. More...

AbstractInputupdInput (const std::string &name)
Get a writable reference to an Input provided by this Component by name. More...

template<typename T >
const Input< T > & getInput (const std::string &name) const
Get a concrete Input that you can directly ask for its values. More...

const AbstractOutputgetOutput (const std::string &name) const
Get the Output provided by this Component by name. More...

AbstractOutputupdOutput (const std::string &name)
Get a writable reference to an Output provided by this Component by name. More...

SimTK::IteratorRange< OutputConstIteratorgetOutputs () const
Iterate through all Outputs of this component. More...

const ComponentgetOwner () const
Access the owner of this Component. More...

bool hasOwner () const
(For advanced users) Check if this Component has an owner. More...

const ComponentgetRoot () const
Obtain the root Component, which is this component if it is orphaned. 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...

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

## Public Types

typedef MuscleFixedWidthPennationModel Self
This typedef might be useful within the member functions of this class. More...

typedef ModelComponent Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::ModelComponent
typedef ModelComponent Self
This typedef might be useful within the member functions of this class. More...

typedef Component Super
Use this typedef to refer to the superclass of this class. More...

Public Types inherited from OpenSim::Component
typedef Component Self
This typedef might be useful within the member functions of this class. More...

typedef Object Super
Use this typedef to refer to the superclass of this class. More...

typedef std::map< std::string, SimTK::ClonePtr< AbstractOutput > >::const_iterator OutputConstIterator
Define OutputConstIterator for convenience. More...

## Protected Member Functions

void extendFinalizeFromProperties () override
Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component. More...

Protected Member Functions inherited from OpenSim::ModelComponent
const SimTK::Vec3 & getScaleFactors (const ScaleSet &scaleSet, const Frame &frame) const
Get the scale factors corresponding to the base OpenSim::Body of the specified Frame. More...

virtual void extendPreScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...

virtual void extendScale (const SimTK::State &s, const ScaleSet &scaleSet)
Scale the ModelComponent. More...

virtual void extendPostScale (const SimTK::State &s, const ScaleSet &scaleSet)
Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...

void updateFromXMLNode (SimTK::Xml::Element &aNode, int versionNumber) override
Handle a change in XML syntax for Sockets. More...

void extendFinalizeFromProperties () override
Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component. More...

virtual void extendConnectToModel (Model &model)
Perform any necessary initializations required to connect the component into the Model, and check for error conditions. More...

Protected Member Functions inherited from OpenSim::Component
SimTK_DEFINE_UNIQUE_INDEX_TYPE (MemberSubcomponentIndex)

template<class C = Component>
MemberSubcomponentIndex constructSubcomponent (const std::string &name)
Construct a subcomponent as a data member of this Component. More...

template<class C = Component>
const C & getMemberSubcomponent (MemberSubcomponentIndex ix) const

template<class C = Component>
C & updMemberSubcomponent (MemberSubcomponentIndex ix)

Adopt a component as a subcomponent of this Component. More...

size_t getNumImmediateSubcomponents () const
Get the number of Subcomponents immediately owned by this Component. More...

size_t getNumMemberSubcomponents () const
Get the number of Subcomponents that are data members of this Component. More...

size_t getNumPropertySubcomponents () const
Get the number of Subcomponents that are properties of this Component. More...

Get the number of Subcomponents adopted by this Component. More...

std::vector< SimTK::ReferencePtr< const Component > > getImmediateSubcomponents () const
Access this Component's immediate subcomponents (not those owned by subcomponents) More...

template<class C >
const C * traversePathToComponent (ComponentPath path) const

void setNextSubcomponentInSystem (const Component &sub) const
Helper method to enable Component makers to specify the order of their subcomponents to be added to the System during addToSystem(). More...

void resetSubcomponentOrder ()
resetSubcomponentOrder clears this Component's list of ordered subcomponents (but otherwise leaves subcomponents untouched). More...

const Componentget_components (int i) const
Get the value of the i-th element of the components property. More...

Componentupd_components (int i)
Get a writable reference to the i-th element of the components property. More...

void set_components (int i, const Component &value)
Set the value of the i-th element of components property. More...

int append_components (const Component &value)
Append an element to the components property. More...

Perform any secondary operations, e.g. More...

void initComponentTreeTraversal (const Component &root) const
Build the tree of Components from this component through its descendants. More...

virtual void extendAddToSystem (SimTK::MultibodySystem &system) const
Add appropriate Simbody elements (if needed) to the System corresponding to this component and specify needed state resources. More...

virtual void extendAddToSystemAfterSubcomponents (SimTK::MultibodySystem &system) const
Add appropriate Simbody elements (if needed) to the System after your component's subcomponents have had a chance to add themselves to the system. More...

virtual void extendInitStateFromProperties (SimTK::State &state) const
Transfer property values or other state-independent initial values into this component's state variables in the passed-in state argument. More...

virtual void extendSetPropertiesFromState (const SimTK::State &state)
Update this component's property values to match the specified State, if the component has created any state variable that is intended to correspond to a property. More...

virtual void computeStateVariableDerivatives (const SimTK::State &s) const
If a model component has allocated any continuous state variables using the addStateVariable() method, then computeStateVariableDerivatives() must be implemented to provide time derivatives for those states. More...

void setStateVariableDerivativeValue (const SimTK::State &state, const std::string &name, double deriv) const
Set the derivative of a state variable by name when computed inside of this Component's computeStateVariableDerivatives() method. More...

virtual void extendRealizeTopology (SimTK::State &state) const
Obtain state resources that are needed unconditionally, and perform computations that depend only on the system topology. More...

virtual void extendRealizeModel (SimTK::State &state) const
Obtain and name state resources (like state variables allocated by an underlying Simbody component) that may be needed, depending on modeling options. More...

virtual void extendRealizeInstance (const SimTK::State &state) const
Perform computations that depend only on instance variables, like lengths and masses. More...

virtual void extendRealizeTime (const SimTK::State &state) const
Perform computations that depend only on time and earlier stages. More...

virtual void extendRealizePosition (const SimTK::State &state) const
Perform computations that depend only on position-level state variables and computations performed in earlier stages (including time). More...

virtual void extendRealizeVelocity (const SimTK::State &state) const
Perform computations that depend only on velocity-level state variables and computations performed in earlier stages (including position, and time). More...

virtual void extendRealizeDynamics (const SimTK::State &state) const
Perform computations (typically forces) that may depend on dynamics-stage state variables, and on computations performed in earlier stages (including velocity, position, and time), but not on other forces, accelerations, constraint multipliers, or reaction forces. More...

virtual void extendRealizeAcceleration (const SimTK::State &state) const
Perform computations that may depend on applied forces. More...

virtual void extendRealizeReport (const SimTK::State &state) const
Perform computations that may depend on anything but are only used for reporting and cannot affect subsequent simulation behavior. More...

void addModelingOption (const std::string &optionName, int maxFlagValue) const
Add a modeling option (integer flag stored in the State) for use by this Component. More...

void addStateVariable (const std::string &stateVariableName, const SimTK::Stage &invalidatesStage=SimTK::Stage::Dynamics, bool isHidden=false) const
Add a continuous system state variable belonging to this Component, and assign a name by which to refer to it. More...

The above method provides a convenient interface to this method, which automatically creates an 'AddedStateVariable' and allocates resources in the SimTK::State for this variable. More...

void addDiscreteVariable (const std::string &discreteVariableName, SimTK::Stage invalidatesStage) const
Add a system discrete variable belonging to this Component, give it a name by which it can be referenced, and declare the lowest Stage that should be invalidated if this variable's value is changed. More...

template<class T >
void addCacheVariable (const std::string &cacheVariableName, const T &variablePrototype, SimTK::Stage dependsOnStage) const
Add a state cache entry belonging to this Component to hold calculated values that must be automatically invalidated when certain state values change. More...

SimTK::MultibodySystem & updSystem () const
Get writable reference to the MultibodySystem that this component is connected to. More...

const int getStateIndex (const std::string &name) const
Get the index of a Component's continuous state variable in the Subsystem for allocations. More...

SimTK::SystemYIndex getStateVariableSystemIndex (const std::string &stateVariableName) const
Get the System Index of a state variable allocated by this Component. More...

const SimTK::DiscreteVariableIndex getDiscreteVariableIndex (const std::string &name) const
Get the index of a Component's discrete variable in the Subsystem for allocations. More...

const SimTK::CacheEntryIndex getCacheVariableIndex (const std::string &name) const
Get the index of a Component's cache variable in the Subsystem for allocations. More...

template<typename T >
PropertyIndex constructSocket (const std::string &name, const std::string &propertyComment)
Construct a specialized Socket for this Component's dependence on another Component. More...

template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
Construct an output for a member function of the same component. More...

template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, const T &(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
This variant handles component member functions that return the output value by const reference (const T&). More...

template<typename T , typename CompType >
bool constructListOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &, const std::string &channel) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
Construct an output that can have multiple channels. More...

bool constructOutputForStateVariable (const std::string &name)
Construct an Output for a StateVariable. More...

template<typename T >
PropertyIndex constructInput (const std::string &name, bool isList, const std::string &propertyComment, const SimTK::Stage &requiredAtStage=SimTK::Stage::Instance)
Construct an Input (socket) for this Component's dependence on an Output signal. More...

void setOwner (const Component &owner)
Set this Component's reference to its owning Component More...

Protected Member Functions inherited from OpenSim::Object
Object ()
The default constructor is only for use by constructors of derived types. More...

Object (const std::string &fileName, bool aUpdateFromXMLNode=true)
Constructor from a file, to be called from other constructors that take a file as input. More...

Object (const Object &source)
Copy constructor is invoked automatically by derived classes with default copy constructors; otherwise it must be invoked explicitly. More...

Object (SimTK::Xml::Element &aElement)
Construct the base class portion of an Object from a given Xml element that describes this Object. More...

template<class T >
PropertyIndex addProperty (const std::string &name, const std::string &comment, const T &value)
Define a new single-value property of known type T, with the given name, associated comment, and initial value. More...

template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment)
Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment, const T &value)
Add an optional property, meaning it can contain either no value or a single value. More...

template<class T >
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize)
Define a new list-valued property of known type T, with the given name, associated comment, minimum (==0) and maximum (>0) allowable list lengths, and a zero-length initial value. More...

template<class T , template< class > class Container>
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize, const Container< T > &valueList)
Define a new list-valued property as above, but assigning an initial value via some templatized container class that supports size() and indexing. More...

PropertyIndex getPropertyIndex (const std::string &name) const
Look up a property by name and return its PropertyIndex if it is found. More...

template<class T >
PropertyIndex getPropertyIndex () const
Look up an unnamed property by the type of object it contains, and return its PropertyIndex if it is found. More...

void setObjectIsUpToDateWithProperties ()
When an object is initialized using the current values of its properties, it can set a flag indicating that it is up to date. More...

void clearObjectIsUpToDateWithProperties ()
For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag. More...

void makeObjectNamesConsistentWithProperties ()
Make sure the name of an object is consistent with its property type. More...

void updateFromXMLDocument ()
Use this method only if you're deserializing from a file and the object is at the top level; that is, primarily in constructors that take a file name as input. More...

void setDocument (XMLDocument *doc)
Unconditionally set the XMLDocument associated with this object. More...

const XMLDocumentgetDocument () const
Get a const pointer to the document (if any) associated with this object. More...

XMLDocumentupdDocument ()
Get a writable pointer to the document (if any) associated with this object. More...

## Friends

class Thelen2003Muscle

class Millard2012EquilibriumMuscle

class Millard2012AccelerationMuscle

## Auto-generated functions

static MuscleFixedWidthPennationModelsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "MuscleFixedWidthPennationModel". More...

void assign (Object &aObject) override
This allows copy assignment in the Java GUI. More...

MuscleFixedWidthPennationModelclone () 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...

Static Public Member Functions inherited from OpenSim::ModelComponent
static ModelComponentsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "ModelComponent". More...

Static Public Member Functions inherited from OpenSim::Component
static ComponentsafeDownCast (OpenSim::Object *obj)
For use in MATLAB and Python to access the concrete class. More...

static const std::string & getClassName ()
This returns "Component". 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 debug level to get verbose output. More...

static int getDebugLevel ()
Get 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...

Static Public Attributes inherited from OpenSim::Object
static const std::string DEFAULT_NAME
Name used for default objects when they are serialized. More...

Static Protected Member Functions inherited from OpenSim::Component
static void prependComponentPathToConnecteePath (Component &subcomponent)
For internal use. More...

Protected Attributes inherited from OpenSim::ModelComponent
SimTK::ReferencePtr< Model_model
The model this component belongs to. More...

Protected Attributes inherited from OpenSim::Object
PropertySet _propertySet
OBSOLETE: Property_Deprecated set for serializable member variables of this and derived classes. More...

Static Protected Attributes inherited from OpenSim::ModelComponent
static const SimTK::Vec3 InvalidScaleFactors
Returned by getScaleFactors() if the ScaleSet does not contain scale factors for the base Body associated with the specified Frame. More...

## Detailed Description

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

This pennation model makes several assumptions:

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

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

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

Conditions

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


Default Parameter Values

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


Example

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

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

References

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

## ◆ Self

This typedef might be useful within the member functions of this class.

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ Super

Use this typedef to refer to the superclass of this class.

Avoid using the explicit type name of the superclass; this would introduce bugs if the superclass is changed.

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ MuscleFixedWidthPennationModel() [1/2]

 OpenSim::MuscleFixedWidthPennationModel::MuscleFixedWidthPennationModel ( )

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

## ◆ MuscleFixedWidthPennationModel() [2/2]

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

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

## ◆ assign()

 void OpenSim::MuscleFixedWidthPennationModel::assign ( Object & aObject )
inlineoverride

This allows copy assignment in the Java GUI.

Exceptions
 Exception if the argument is not of type MuscleFixedWidthPennationModel.

## ◆ calc_DFiberLengthAlongTendon_DfiberLength()

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

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

## ◆ calc_DFiberVelocityAlongTendon_DfiberLength()

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

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

## ◆ calc_DPennationAngle_DfiberLength()

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

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

## ◆ calc_DPennationAngularVelocity_DfiberLength()

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

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

## ◆ calc_DTendonLength_DfiberLength()

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

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

## ◆ calcFiberAccelerationAlongTendon()

 double OpenSim::MuscleFixedWidthPennationModel::calcFiberAccelerationAlongTendon ( double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity, double pennationAngularAcceleration ) const
Parameters
 fiberLength The length of the fiber (m). fiberVelocity The lengthening velocity of the fiber (m/s). fiberAcceleration The lengthening acceleration of the fiber (m/s^2). sinPennationAngle The sine of the pennation angle. cosPennationAngle The cosine of the pennation angle. pennationAngularVelocity The angular velocity of the parallelogram (rad/s). pennationAngularAcceleration The angular acceleration of the parallelogram (rad/s^2).
Returns
The acceleration of the fiber projected onto the axis of the tendon (m/s^2).

## ◆ calcFiberLength()

 double OpenSim::MuscleFixedWidthPennationModel::calcFiberLength ( double muscleLength, double tendonLength ) const
Parameters
 muscleLength The length of the musculotendon actuator (m). tendonLength The length of the tendon (m).
Returns
The length of the fiber (m).

## ◆ calcFiberLengthAlongTendon()

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

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

## ◆ calcFiberVelocity()

 double OpenSim::MuscleFixedWidthPennationModel::calcFiberVelocity ( double cosPennationAngle, double muscleVelocity, double tendonVelocity ) const
Parameters
 cosPennationAngle The cosine of the pennation angle. muscleVelocity The lengthening velocity of the musculotendon actuator (m/s). tendonVelocity The lengthening velocity of the tendon (m/s).
Returns
The lengthening velocity of the fiber (m/s).

## ◆ calcFiberVelocityAlongTendon()

 double OpenSim::MuscleFixedWidthPennationModel::calcFiberVelocityAlongTendon ( double fiberLength, double fiberVelocity, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity ) const
Parameters
 fiberLength The length of the fiber (m). fiberVelocity The lengthening velocity of the fiber (m/s). sinPennationAngle The sine of the pennation angle. cosPennationAngle The cosine of the pennation angle. pennationAngularVelocity The angular velocity of the parallelogram (rad/s).
Returns
The lengthening velocity of the fiber projected onto the axis of the tendon (m/s).

## ◆ calcPennationAngle()

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

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

## ◆ calcPennationAngularAcceleration()

 double OpenSim::MuscleFixedWidthPennationModel::calcPennationAngularAcceleration ( double fiberLength, double fiberVelocity, double fiberAcceleration, double sinPennationAngle, double cosPennationAngle, double pennationAngularVelocity ) const
Parameters
 fiberLength The length of the fiber (m). fiberVelocity The lengthening velocity of the fiber (m/s). fiberAcceleration The lengthening acceleration of the fiber (m/s^2). sinPennationAngle The sine of the pennation angle. cosPennationAngle The cosine of the pennation angle. pennationAngularVelocity The angular velocity of the parallelogram (rad/s).
Returns
The angular acceleration of the parallelogram (rad/s^2).

## ◆ calcPennationAngularVelocity()

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

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

Parameters
 tanPennationAngle The tangent of the pennation angle. fiberLength The length of the fiber (m). fiberVelocity The lengthening velocity of the fiber (m/s).
Returns
The angular velocity of the parallelogram (rad/s).

## ◆ calcTendonLength()

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

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

## ◆ calcTendonVelocity()

 double OpenSim::MuscleFixedWidthPennationModel::calcTendonVelocity ( double cosPennationAngle, double sinPennationAngle, double pennationAngularVelocity, double fiberLength, double fiberVelocity, double muscleVelocity ) const
Parameters
 cosPennationAngle The cosine of the pennation angle. sinPennationAngle The sine of the pennation angle. pennationAngularVelocity The angular velocity of the parallelogram (rad/s). fiberLength The length of the fiber (m). fiberVelocity The lengthening velocity of the fiber (m/s). muscleVelocity The lengthening velocity of the muscle path (m/s).
Returns
The lengthening velocity of the tendon (m/s).

## ◆ clone()

 MuscleFixedWidthPennationModel* OpenSim::MuscleFixedWidthPennationModel::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::ModelComponent.

## ◆ extendFinalizeFromProperties()

 void OpenSim::MuscleFixedWidthPennationModel::extendFinalizeFromProperties ( )
overrideprotectedvirtual

Perform any time-invariant calculations, data structure initializations, or other configuration based on the component's properties to form a functioning (but not yet connected) component.

For example, each property should be checked to ensure that its value is within an acceptable range. When this method returns, the component will be marked as being up-to-date with its properties. Do not perform any configuration that depends on the SimTK::MultibodySystem; it is not available at this point.

If you override this method, be sure to invoke the base class method first, using code like this:

void MyComponent::extendFinalizeFromProperties() {
Super::extendFinalizeFromProperties(); // invoke parent class method
// ... your code goes here
// ... catch invalid property values
// ... initialize any internal data structures
}

Reimplemented from OpenSim::Component.

## ◆ get_maximum_pennation_angle()

 const double& OpenSim::MuscleFixedWidthPennationModel::get_maximum_pennation_angle ( ) const
inline

Get the value of the maximum_pennation_angle property.

## ◆ get_optimal_fiber_length()

 const double& OpenSim::MuscleFixedWidthPennationModel::get_optimal_fiber_length ( ) const
inline

Get the value of the optimal_fiber_length property.

## ◆ get_pennation_angle_at_optimal()

 const double& OpenSim::MuscleFixedWidthPennationModel::get_pennation_angle_at_optimal ( ) const
inline

Get the value of the pennation_angle_at_optimal property.

## ◆ getClassName()

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

This returns "MuscleFixedWidthPennationModel".

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

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

## ◆ getConcreteClassName()

 const std::string& OpenSim::MuscleFixedWidthPennationModel::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.

getClassName()

Implements OpenSim::ModelComponent.

## ◆ getMinimumFiberLength()

 double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLength ( ) const
Returns
The minimum possible fiber length.

## ◆ getMinimumFiberLengthAlongTendon()

 double OpenSim::MuscleFixedWidthPennationModel::getMinimumFiberLengthAlongTendon ( ) const
Returns
The minimum possible fiber length along the tendon.

## ◆ getParallelogramHeight()

 double OpenSim::MuscleFixedWidthPennationModel::getParallelogramHeight ( ) const
Returns
The height of the fixed-width parallelogram.

## ◆ safeDownCast()

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

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

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

## ◆ set_maximum_pennation_angle()

 void OpenSim::MuscleFixedWidthPennationModel::set_maximum_pennation_angle ( const double & value )
inline

Set the value of the maximum_pennation_angle property.

## ◆ set_optimal_fiber_length()

 void OpenSim::MuscleFixedWidthPennationModel::set_optimal_fiber_length ( const double & value )
inline

Set the value of the optimal_fiber_length property.

## ◆ set_pennation_angle_at_optimal()

 void OpenSim::MuscleFixedWidthPennationModel::set_pennation_angle_at_optimal ( const double & value )
inline

Set the value of the pennation_angle_at_optimal property.

## ◆ upd_maximum_pennation_angle()

 double& OpenSim::MuscleFixedWidthPennationModel::upd_maximum_pennation_angle ( )
inline

Get a writable reference to the maximum_pennation_angle property.

## ◆ upd_optimal_fiber_length()

 double& OpenSim::MuscleFixedWidthPennationModel::upd_optimal_fiber_length ( )
inline

Get a writable reference to the optimal_fiber_length property.

## ◆ upd_pennation_angle_at_optimal()

 double& OpenSim::MuscleFixedWidthPennationModel::upd_pennation_angle_at_optimal ( )
inline

Get a writable reference to the pennation_angle_at_optimal property.

## ◆ Millard2012AccelerationMuscle

 friend class Millard2012AccelerationMuscle
friend

## ◆ Millard2012EquilibriumMuscle

 friend class Millard2012EquilibriumMuscle
friend

## ◆ Thelen2003Muscle

 friend class Thelen2003Muscle
friend

## ◆ maximum_pennation_angle

 double OpenSim::MuscleFixedWidthPennationModel::maximum_pennation_angle

"Maximum pennation angle, in radians (overridden when this is a subcomponent of a Muscle)"

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

get_maximum_pennation_angle(), upd_maximum_pennation_angle(), set_maximum_pennation_angle()

## ◆ optimal_fiber_length

 double OpenSim::MuscleFixedWidthPennationModel::optimal_fiber_length

"Optimal length of the muscle fibers, in meters (overridden when this is a subcomponent of a Muscle)"

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

get_optimal_fiber_length(), upd_optimal_fiber_length(), set_optimal_fiber_length()

## ◆ pennation_angle_at_optimal

 double OpenSim::MuscleFixedWidthPennationModel::pennation_angle_at_optimal

"Angle between tendon and fibers at optimal fiber length, in radians (overridden when this is a subcomponent of a Muscle)"

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