A base class for modeling a muscle-tendon actuator. More...

#include <Muscle.h>

Inheritance diagram for OpenSim::Muscle:

Classes
struct	FiberVelocityInfo
	FiberVelocityInfo contains velocity quantities related to the velocity of the muscle (fiber + tendon) complex. More...
struct	MuscleDynamicsInfo
	MuscleDynamicsInfo contains quantities that are related to the forces that the muscle generates. More...
struct	MuscleLengthInfo
	The MuscleLengthInfo struct contains information about the muscle that is strictly a function of the length of the fiber and the tendon, and the orientation of the muscle fiber. More...

Public Member Functions
double	computeActuation (const SimTK::State &s) const =0
	Actuator interface for a muscle computes the tension in the muscle and applied by the tendon to bones (i.e.
Property declarations
These are the serializable properties associated with the Muscle class. Note that concrete muscles derived from this class inherit all these properties.
	OpenSim_DECLARE_PROPERTY (max_isometric_force, double,"Maximum isometric force that the fibers can generate")
	OpenSim_DECLARE_PROPERTY (optimal_fiber_length, double,"Optimal length of the muscle fibers")
	OpenSim_DECLARE_PROPERTY (tendon_slack_length, double,"Resting length of the tendon")
	OpenSim_DECLARE_PROPERTY (pennation_angle_at_optimal, double,"Angle between tendon and fibers at optimal fiber length expressed in radians")
	OpenSim_DECLARE_PROPERTY (max_contraction_velocity, double,"Maximum contraction velocity of the fibers, in optimal fiberlengths/second")
	OpenSim_DECLARE_PROPERTY (ignore_tendon_compliance, bool,"Compute muscle dynamics ignoring tendon compliance. Tendon is assumed to be rigid.")
	OpenSim_DECLARE_PROPERTY (ignore_activation_dynamics, bool,"Compute muscle dynamics ignoring activation dynamics. Activation is equivalent to excitation.")
Constructors and Destructor
	Muscle ()
	Default constructor.
Muscle Parameters Access Methods
double	getMaxIsometricForce () const
	get/set the maximum isometric force (in N) that the fibers can generate
void	setMaxIsometricForce (double maxIsometricForce)
double	getOptimalFiberLength () const
	get/set the optimal length (in m) of the muscle fibers (lumped as a single fiber)
void	setOptimalFiberLength (double optimalFiberLength)
double	getTendonSlackLength () const
	get/set the resting (slack) length (in m) of the tendon that is in series with the muscle fiber
void	setTendonSlackLength (double tendonSlackLength)
double	getPennationAngleAtOptimalFiberLength () const
	get/set the angle (in radians) between fibers at their optimal fiber length and the tendon
void	setPennationAngleAtOptimalFiberLength (double pennationAngle)
double	getMaxContractionVelocity () const
	get/set the maximum contraction velocity of the fibers, in optimal fiber-lengths per second
void	setMaxContractionVelocity (double maxContractionVelocity)
Muscle State Dependent Access Methods
Get quantities of interest common to all muscles
bool	getIgnoreTendonCompliance (const SimTK::State &s) const
	Get/set Modeling (runtime) option to ignore tendon compliance when computing muscle dynamics.
void	setIgnoreTendonCompliance (SimTK::State &s, bool ignore) const
bool	getIgnoreActivationDynamics (const SimTK::State &s) const
	Get/set Modeling (runtime) option to ignore activation dynamics when computing muscle dynamics.
void	setIgnoreActivationDynamics (SimTK::State &s, bool ignore) const
virtual double	getActivation (const SimTK::State &s) const
	get the activation level of the muscle, which modulates the active force of the muscle and has a normalized (0 to 1) value TODO: virtual to allow override by deprecated muscles.
double	getFiberLength (const SimTK::State &s) const
	get the current working fiber length (m) for the muscle
double	getPennationAngle (const SimTK::State &s) const
	get the current pennation angle (radians) between the fiber and tendon at the current fiber length
double	getTendonLength (const SimTK::State &s) const
	get the current tendon length (m) given the current joint angles and fiber length
double	getNormalizedFiberLength (const SimTK::State &s) const
	get the current normalized fiber length (fiber_length/optimal_fiber_length)
double	getFiberLengthAlongTendon (const SimTK::State &s) const
	get the current fiber length (m) projected (*cos(pennationAngle)) onto the tendon direction
double	getTendonStrain (const SimTK::State &s) const
	get the current tendon strain (delta_l/tendon_slack_length is dimensionless)
double	getFiberPotentialEnergy (const SimTK::State &s) const
	the potential energy (J) stored in the fiber due to its parallel elastic element
double	getTendonPotentialEnergy (const SimTK::State &s) const
	the potential energy (J) stored in the tendon
double	getMusclePotentialEnergy (const SimTK::State &s) const
	the total potential energy (J) stored in the muscle
double	getPassiveForceMultiplier (const SimTK::State &s) const
	get the passive fiber (parallel elastic element) force multiplier
double	getActiveForceLengthMultiplier (const SimTK::State &s) const
	get the active fiber (contractile element) force multiplier due to current fiber length
double	getFiberVelocity (const SimTK::State &s) const
	get current fiber velocity (m/s) positive is lengthening
double	getNormalizedFiberVelocity (const SimTK::State &s) const
	get normalize fiber velocity (fiber_lengths/s / max_contraction_velocity)
double	getFiberVelocityAlongTendon (const SimTK::State &s) const
	get the current afiber velocity (m/s) projected onto the tendon direction
double	getPennationAngularVelocity (const SimTK::State &s) const
	get pennation angular velocity (radians/s)
double	getTendonVelocity (const SimTK::State &s) const
	get the tendon velocity (m/s) positive is lengthening
double	getForceVelocityMultiplier (const SimTK::State &s) const
	get the dimensionless multiplier resulting from the fiber's force-velocity curve
double	getFiberForce (const SimTK::State &s) const
	get the current fiber force (N) applied to the tendon
double	getActiveFiberForce (const SimTK::State &s) const
	get the current active fiber force (N) due to activationforce_lengthforce_velocity relationships
double	getPassiveFiberForce (const SimTK::State &s) const
	get the current passive fiber force (N) passive_force_length relationship
double	getActiveFiberForceAlongTendon (const SimTK::State &s) const
	get the current active fiber force (N) projected onto the tendon direction
double	getPassiveFiberForceAlongTendon (const SimTK::State &s) const
	get the current passive fiber force (N) projected onto the tendon direction
double	getTendonForce (const SimTK::State &s) const
	get the current tendon force (N) applied to bones
double	getFiberStiffness (const SimTK::State &s) const
	get the current fiber stiffness (N/m) defined as the partial derivative of fiber force w.r.t.
double	getTendonStiffness (const SimTK::State &s) const
	get the current tendon stiffness (N/m) defined as the partial derivative of tendon force w.r.t.
double	getMuscleStiffness (const SimTK::State &s) const
	get the current muscle stiffness (N/m) defined as the partial derivative of muscle force w.r.t.
double	getFiberActivePower (const SimTK::State &s) const
	get the current active fiber power (W)
double	getFiberPassivePower (const SimTK::State &s) const
	get the current passive fiber power (W)
double	getTendonPower (const SimTK::State &s) const
	get the current tendon power (W)
double	getMusclePower (const SimTK::State &s) const
	get the current muscle power (W)
double	getStress (const SimTK::State &s) const
	get the stress in the muscle (part of the Actuator interface as well)
void	setExcitation (SimTK::State &s, double excitation) const
	set the excitation (control) for this muscle.
double	getExcitation (const SimTK::State &s) const
virtual void	setActivation (SimTK::State &s, double activation) const =0
	DEPRECATED: only for backward compatibility.
Muscle initialization
void	equilibrate (SimTK::State &s) const
	Find and set the equilibrium state of the muscle (if any)
Public Member Functions inherited from OpenSim::PathActuator
	PathActuator ()
GeometryPath &	updGeometryPath ()
const GeometryPath &	getGeometryPath () const
virtual bool	hasGeometryPath () const
	Return a flag indicating whether the Force is applied along a Path.
void	setOptimalForce (double aOptimalForce)
double	getOptimalForce () const
virtual double	getLength (const SimTK::State &s) const
virtual double	getLengtheningSpeed (const SimTK::State &s) const
virtual double	getPower (const SimTK::State &s) const
void	addNewPathPoint (const std::string &proposedName, OpenSim::Body &aBody, const SimTK::Vec3 &aPositionOnBody)
	Note that this function does not maintain the State and so should be used only before a valid State is created.
virtual double	computeMomentArm (SimTK::State &s, Coordinate &aCoord) const
virtual void	updateFromXMLNode (SimTK::Xml::Element &aNode, int versionNumber=-1)
	Use this method to deserialize an object from a SimTK::Xml::Element.
virtual void	preScale (const SimTK::State &s, const ScaleSet &aScaleSet)
virtual void	scale (const SimTK::State &s, const ScaleSet &aScaleSet)
virtual void	postScale (const SimTK::State &s, const ScaleSet &aScaleSet)
virtual VisibleObject *	getDisplayer () const
	Methods to support making the object displayable in the GUI or Visualizer Implemented only in few objects.
virtual void	updateDisplayer (const SimTK::State &s)
	In case the ModelComponent has a visual representation (VisualObject), override this method to update it.
	OpenSim_DECLARE_UNNAMED_PROPERTY (GeometryPath,"The set of points defining the path of the muscle.")
	OpenSim_DECLARE_PROPERTY (optimal_force, double,"The maximum force this actuator can produce.")
Public Member Functions inherited from OpenSim::Actuator
	Actuator ()
virtual double	getControl (const SimTK::State &s) const
	Convenience method to set controls given scalar (double) valued control.
virtual int	numControls () const
virtual void	setForce (const SimTK::State &s, double aForce) const
virtual double	getForce (const SimTK::State &s) const
virtual void	setSpeed (const SimTK::State &s, double aspeed) const
virtual double	getSpeed (const SimTK::State &s) const
void	setMinControl (const double &aMinControl)
double	getMinControl () const
void	setMaxControl (const double &aMaxControl)
double	getMaxControl () const
void	overrideForce (SimTK::State &s, bool flag) const
	Overriding forces The force normally produced by an Actuator can be overriden and When the Actuator's force is overriden, the Actuator will by defualt produce a constant force which can be set with setOverrideForce().
bool	isForceOverriden (const SimTK::State &s) const
	return Actuator's override status
void	setOverrideForce (SimTK::State &s, double value) const
	set the force value used when the override is true
double	getOverrideForce (const SimTK::State &s) const
	return override force
	OpenSim_DECLARE_PROPERTY (min_control, double,"Minimum allowed value for control signal. Used primarily when solving ""for control values.")
	Default is -Infinity (no limit).
	OpenSim_DECLARE_PROPERTY (max_control, double,"Maximum allowed value for control signal. Used primarily when solving ""for control values.")
	Default is Infinity (no limit).
Public Member Functions inherited from OpenSim::Actuator_
	Actuator_ ()
virtual const SimTK::Vector	getDefaultControls ()
	Actuator default controls are zero.
virtual const SimTK::VectorView_< double >	getControls (const SimTK::State &s) const
virtual void	getControls (const SimTK::Vector &modelControls, SimTK::Vector &actuatorControls) const
	Convenience methods for getting, setting and adding to actuator controls from/into the model controls.
virtual void	setControls (const SimTK::Vector &actuatorControls, SimTK::Vector &modelControls) const
	set actuator controls subvector into the right slot in the system-wide model controls
virtual void	addInControls (const SimTK::Vector &actuatorControls, SimTK::Vector &modelControls) const
	add actuator controls to the values already occupying the slot in the system-wide model controls
virtual void	computeEquilibrium (SimTK::State &s) const
Public Member Functions inherited from OpenSim::Force
	Force (const Force &aForce)
	Implements a copy constructor just so it can invalidate the SimTK::Force index after copying.
Force &	operator= (const Force &aForce)
	Implements a copy assignment operator just so it can invalidate the SimTK::Force index after the assignment.
bool	isDisabled (const SimTK::State &s) const
	Return if the Force is disabled or not.
void	setDisabled (SimTK::State &s, bool disabled)
	Set the Force as disabled (true) or not (false).
	OpenSim_DECLARE_PROPERTY (isDisabled, bool,"Flag indicating whether the force is disabled or not. Disabled means"" that the force is not active in subsequent dynamics realizations.")
	A Force element is active (enabled) by default.
Public Member Functions inherited from OpenSim::ModelComponent
	ModelComponent ()
	Default constructor.
	ModelComponent (const std::string &aFileName, bool aUpdateFromXMLNode=true) SWIG_DECLARE_EXCEPTION
	Construct ModelComponent from an XML file.
	ModelComponent (SimTK::Xml::Element &aNode)
	Construct ModelComponent from a specific node in an XML document.
	ModelComponent (const ModelComponent &source)
	Construct ModelComponent with its contents copied from another ModelComponent; this is a deep copy so nothing is shared with the source after the copy.
virtual	~ModelComponent ()
	Destructor is virtual to allow concrete model component cleanup.
ModelComponent &	operator= (const ModelComponent &aModelComponent)
	Assignment operator to copy contents of an existing component.
const Model &	getModel () const
	Get a const reference to the Model this component is part of.
Model &	updModel ()
	Get a modifiable reference to the Model this component is part of.
virtual int	getNumStateVariables () const
	Get the number of "Continuous" state variables maintained by the ModelComponent and its specified subcomponents.
virtual Array< std::string >	getStateVariableNames () const
	Get the names of "continuous" state variables maintained by the ModelComponent and its subcomponents.
virtual SimTK::SystemYIndex	getStateVariableSystemIndex (const std::string &stateVariableName) const
	Get the System Index of a state variable allocated by this ModelComponent.
int	getModelingOption (const SimTK::State &state, const std::string &name) const
	Get a ModelingOption flag for this ModelComponent by name.
void	setModelingOption (SimTK::State &state, const std::string &name, int flag) const
	Set the value of a ModelingOption flag for this ModelComponent.
double	getStateVariable (const SimTK::State &state, const std::string &name) const
	Get the value of a state variable allocated by this ModelComponent.
void	setStateVariable (SimTK::State &state, const std::string &name, double value) const
	Set the value of a state variable allocated by this ModelComponent by name.
double	getDiscreteVariable (const SimTK::State &state, const std::string &name) const
	Get the value of a discrete variable allocated by this ModelComponent by name.
void	setDiscreteVariable (SimTK::State &state, const std::string &name, double value) const
	Set the value of a discrete variable allocated by this ModelComponent by name.
template<typename T >
const T &	getCacheVariable (const SimTK::State &state, const std::string &name) const
	Get the value of a cache variable allocated by this ModelComponent by name.
template<typename T >
T &	updCacheVariable (const SimTK::State &state, const std::string &name) const
	Obtain a writable cache variable value allocated by this ModelComponent by name.
void	markCacheVariableValid (const SimTK::State &state, const std::string &name) const
	After updating a cache variable value allocated by this ModelComponent, 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.
void	markCacheVariableInvalid (const SimTK::State &state, const std::string &name) const
	Mark a cache variable value allocated by this ModelComponent as invalid.
bool	isCacheVariableValid (const SimTK::State &state, const std::string &name) const
	Enables the to monitor the validity of the cache variable value using the returned flag.
template<typename T >
void	setCacheVariable (const SimTK::State &state, const std::string &name, T &value) const
	Set cache variable value allocated by this ModelComponent by name.
Public Member Functions inherited from OpenSim::Object
virtual	~Object ()
	Virtual destructor for cleanup.
virtual Object *	clone () const =0
	Create a new heap-allocated copy of the concrete object to which this Object refers.
virtual const std::string &	getConcreteClassName () const =0
	Returns the class name of the concrete %Object-derived class of the actual object referenced by this Object, as a string.
virtual VisibleObject *	updDisplayer ()
	get Non const pointer to VisibleObject
bool	isEqualTo (const Object &aObject) const
	Equality operator wrapper for use from languages not supporting operator overloading.
Object &	operator= (const Object &aObject)
	Copy assignment copies he base class fields, including the properties.
virtual bool	operator== (const Object &aObject) const
	Determine if two objects are equal.
virtual bool	operator< (const Object &aObject) const
	Provide an ordering for objects so they can be put in sorted containers.
void	setName (const std::string &name)
	Set the name of the Object.
const std::string &	getName () const
	Get the name of this Object.
void	setDescription (const std::string &description)
	Set description, a one-liner summary.
const std::string &	getDescription () const
	Get description, a one-liner summary.
const std::string &	getAuthors () const
	Get Authors of this Object.
void	setAuthors (const std::string &authors)
	Set Authors of this object, call this method in your constructor if needed.
const std::string &	getReferences () const
	Get references or publications to cite if using this object.
void	setReferences (const std::string &references)
	Set references or publications to cite if using this object.
int	getNumProperties () const
	Determine how many properties are stored with this Object.
const AbstractProperty &	getPropertyByIndex (int propertyIndex) const
	Get a const reference to a property by its index number, returned as an AbstractProperty.
AbstractProperty &	updPropertyByIndex (int propertyIndex)
	Get a writable reference to a property by its index number, returned as an AbstractProperty.
bool	hasProperty (const std::string &name) const
	Return true if this %Object has a property of any type with the given name, which must not be empty.
const AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty.
AbstractProperty &	updPropertyByName (const std::string &name)
	Get a writable reference to a property by its name, returned as an AbstractProperty.
template<class T >
bool	hasProperty () const
	Return true if this %Object contains an unnamed, one-object property that contains objects of the given template type T.
template<class T >
const Property< T > &	getProperty (const PropertyIndex &index) const
	Get property of known type Property\<T> as a const reference; the property must be present and have the right type.
template<class T >
Property< T > &	updProperty (const PropertyIndex &index)
	Get property of known type Property\<T> as a writable reference; the property must be present and have the right type.
void	setObjectIsUpToDateWithProperties ()
	When an object is initialized using the current values of its properties, it can set a flag indicating that it is up to date.
bool	isObjectUpToDateWithProperties () const
	Returns \c true if any property's value has changed since the last time setObjectIsUpToDateWithProperties() was called.
void	readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
	We're given an XML element from which we are to populate this Object.
virtual void	updateXMLNode (SimTK::Xml::Element &parent)
	Serialize this object into the XML node that represents it.
bool	getInlined () const
	Inlined means an in-memory Object that is not associated with an XMLDocument.
void	setInlined (bool aInlined, const std::string &aFileName="")
	Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case.
std::string	getDocumentFileName () const
	If there is a document associated with this object then return the file name maintained by the document.
void	setAllPropertiesUseDefault (bool aUseDefault)
bool	print (const std::string &fileName)
	Write this %Object into an XML file of the given name; conventionally the suffix to use is ".osim".
std::string	dump (bool dumpName=false)
	dump the XML representation of this Object into an std::string and return it.
void	clearObjectIsUpToDateWithProperties ()
	For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag.
virtual bool	isA (const char *type) const
	The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name.
const std::string &	toString () const
	Wrapper to be used on Java side to display objects in tree; this returns just the object's name.
PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object.
const PropertySet &	getPropertySet () const

Protected Member Functions
const MuscleLengthInfo &	getMuscleLengthInfo (const SimTK::State &s) const
	Developer Access to intermediate values calculate by the muscle model.
MuscleLengthInfo &	updMuscleLengthInfo (const SimTK::State &s) const
const FiberVelocityInfo &	getFiberVelocityInfo (const SimTK::State &s) const
FiberVelocityInfo &	updFiberVelocityInfo (const SimTK::State &s) const
const MuscleDynamicsInfo &	getMuscleDynamicsInfo (const SimTK::State &s) const
MuscleDynamicsInfo &	updMuscleDynamicsInfo (const SimTK::State &s) const
Muscle State Dependent Calculations
Developers must override these methods to implement the desired behavior of their muscle models. Unless you are augmenting the behavior of an existing muscle class or writing a new derived class, you do not have access to these methods.
virtual void	calcMuscleLengthInfo (const SimTK::State &s, MuscleLengthInfo &mli) const
	calculate muscle's position related values such fiber and tendon lengths, normalized lengths, pennation angle, etc...
virtual void	calcFiberVelocityInfo (const SimTK::State &s, FiberVelocityInfo &fvi) const
	calculate muscle's fiber velocity and pennation angular velocity, etc...
virtual void	calcMuscleDynamicsInfo (const SimTK::State &s, MuscleDynamicsInfo &mdi) const
	calculate muscle's active and passive force-length, force-velocity, tendon force, relationships and their related values
virtual void	computeInitialFiberEquilibrium (SimTK::State &s) const =0
	compute initial fiber length (velocity) such that muscle fiber and tendon are in static equilibrium and update the state
Interfaces imposed by parent classes
virtual void	computeForce (const SimTK::State &state, SimTK::Vector_< SimTK::SpatialVec > &bodyForces, SimTK::Vector &generalizedForce) const
	Force interface applies tension to bodies, and Muscle also checks that applied muscle tension is not negative.
virtual double	computePotentialEnergy (const SimTK::State &state) const
	Potential energy stored by the muscle.
void	connectToModel (Model &aModel) override
	Model Component creation interface.
void	addToSystem (SimTK::MultibodySystem &system) const override
	Default is to create a ForceAdapter which is a SimTK::Force::Custom as the underlying computational component.
void	setPropertiesFromState (const SimTK::State &s) override
	Subclass should override; be sure to invoke Force::setPropertiesFromState() at the beginning of the overriding method.
void	initStateFromProperties (SimTK::State &state) const override
	Subclass should override; be sure to invoke Force::initStateFromProperties() at the beginning of the overriding method.
virtual void	updateGeometry (const SimTK::State &s)

Protected Attributes
double	_muscleWidth
	The assumed fixed muscle-width from which the fiber pennation angle is calculated.
double	_maxIsometricForce
	to support deprecated muscles
double	_optimalFiberLength
double	_pennationAngleAtOptimal
double	_tendonSlackLength

Additional Inherited Members
Static Public Member Functions inherited from OpenSim::Object
static void	registerType (const Object &defaultObject)
	Register an instance of a class; if the class is already registered it will be replaced.
static void	renameType (const std::string &oldTypeName, const std::string &newTypeName)
	Support versioning by associating the current %Object type with an old name.
static const Object *	getDefaultInstanceOfType (const std::string &concreteClassName)
	Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered.
template<class T >
static bool	isObjectTypeDerivedFrom (const std::string &concreteClassName)
	Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*.
static Object *	newInstanceOfType (const std::string &concreteClassName)
	Create a new instance of the concrete %Object type whose class name is given as concreteClassName.
static void	getRegisteredTypenames (Array< std::string > &typeNames)
	Retrieve all the typenames registered so far.
template<class T >
static void	getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
	Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete.
static void	PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName)
	Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects.
static void	PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName)
	Same as the other signature but the class name and property name are provided as two separate strings.
static Object *	makeObjectFromFile (const std::string &fileName)
	Create an %OpenSim object whose type is based on the tag at the root node of the XML file passed in.
static const std::string &	getClassName ()
	Return the name of this class as a string; i.e., "Object".
static void	setSerializeAllDefaults (bool shouldSerializeDefaults)
	Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically.
static bool	getSerializeAllDefaults ()
	Report the value of the "serialize all defaults" flag.
static bool	isKindOf (const char *type)
	Returns true if the passed-in string is "Object"; each %Object-derived class defines a method of this name for its own class name.
static void	setDebugLevel (int newLevel)
	Set the debug level to get verbose output.
static int	getDebugLevel ()
	Get current setting of debug level.
static Object *	SafeCopy (const Object *aObject)
	Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned.
static void	RegisterType (const Object &defaultObject)
	OBSOLETE alternate name for registerType().
static void	RenameType (const std::string &oldName, const std::string &newName)
	OBSOLETE alternate name for renameType().
Static Public Attributes inherited from OpenSim::Object
static const std::string	DEFAULT_NAME
	Name used for default objects when they are serialized.
Related Functions inherited from OpenSim::Object
#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.
#define	OpenSim_DECLARE_ABSTRACT_OBJECT(ConcreteClass, SuperClass)
	Macro to be included as the first line of the class declaration for any still-abstract class that derives from OpenSim::Object.
#define	OpenSim_DECLARE_CONCRETE_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, concrete class that derives from OpenSim::Object, like Set<T>.
#define	OpenSim_DECLARE_ABSTRACT_OBJECT_T(ConcreteClass, TArg, SuperClass)
	Macro to be included as the first line of the class declaration for any templatized, still-abstract class that derives from OpenSim::Object.

Detailed Description

A base class for modeling a muscle-tendon actuator.

It defines muscle parameters and methods to PathActuator, but does not implement all of the necessary methods, and remains an abstract class. The path information for a muscle is contained in PathActuator, and the force-generating behavior should be defined in the derived classes.

This class defines a subset of muscle models that include an active fiber (contractile element) in series with a tendon. This class defines common data members and handles the geometry of a unipennate fiber in connection with a tendon. No states are assumed, but concrete classes are free to add whatever states are necessary to describe the specific behavior of a muscle.

Author: Ajay Seth, Matt Millard

(Based on earlier work by Peter Loan and Frank C. Anderson.)

Constructor & Destructor Documentation

OpenSim::Muscle::Muscle ( )

Default constructor.

Member Function Documentation

void OpenSim::Muscle::addToSystem ( SimTK::MultibodySystem & system ) const

overrideprotectedvirtual

Default is to create a ForceAdapter which is a SimTK::Force::Custom

as the underlying computational component.

Subclasses override to employ other SimTK::Forces; be sure to invoke Force::addToSystem() at the beginning of the overriding method.

Reimplemented from OpenSim::Actuator.

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ContDerivMuscle_Deprecated, OpenSim::Delp1990Muscle_Deprecated, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle.

virtual void OpenSim::Muscle::calcFiberVelocityInfo	(	const SimTK::State &	s,
		FiberVelocityInfo &	fvi
	)		const

protectedvirtual

calculate muscle's fiber velocity and pennation angular velocity, etc...

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::RigidTendonMuscle.

virtual void OpenSim::Muscle::calcMuscleDynamicsInfo	(	const SimTK::State &	s,
		MuscleDynamicsInfo &	mdi
	)		const

protectedvirtual

calculate muscle's active and passive force-length, force-velocity, tendon force, relationships and their related values

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::RigidTendonMuscle.

virtual void OpenSim::Muscle::calcMuscleLengthInfo	(	const SimTK::State &	s,
		MuscleLengthInfo &	mli
	)		const

protectedvirtual

calculate muscle's position related values such fiber and tendon lengths, normalized lengths, pennation angle, etc...

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::RigidTendonMuscle.

double OpenSim::Muscle::computeActuation ( const SimTK::State & s ) const

pure virtual

Actuator interface for a muscle computes the tension in the muscle and applied by the tendon to bones (i.e.

not the fiber force)

Reimplemented from OpenSim::PathActuator.

Implemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ContDerivMuscle_Deprecated, OpenSim::Thelen2003Muscle_Deprecated, OpenSim::Delp1990Muscle_Deprecated, OpenSim::ActivationFiberLengthMuscle_Deprecated, OpenSim::RigidTendonMuscle, and OpenSim::Schutte1993Muscle_Deprecated.

virtual void OpenSim::Muscle::computeForce	(	const SimTK::State &	state,
		SimTK::Vector_< SimTK::SpatialVec > &	bodyForces,
		SimTK::Vector &	generalizedForce
	)		const

protectedvirtual

Force interface applies tension to bodies, and Muscle also checks that applied muscle tension is not negative.

Reimplemented from OpenSim::PathActuator.

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle.

virtual void OpenSim::Muscle::computeInitialFiberEquilibrium ( SimTK::State & s ) const

protectedpure virtual

compute initial fiber length (velocity) such that muscle fiber and tendon are in static equilibrium and update the state

Implemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::Thelen2003Muscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::RigidTendonMuscle.

virtual double OpenSim::Muscle::computePotentialEnergy ( const SimTK::State & state ) const

protectedvirtual

Potential energy stored by the muscle.

Reimplemented from OpenSim::Force.

void OpenSim::Muscle::connectToModel ( Model & aModel )

overrideprotectedvirtual

Model Component creation interface.

Reimplemented from OpenSim::PathActuator.

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::ContDerivMuscle_Deprecated, OpenSim::Delp1990Muscle_Deprecated, and OpenSim::Schutte1993Muscle_Deprecated.

void OpenSim::Muscle::equilibrate ( SimTK::State & s ) const

inline

Find and set the equilibrium state of the muscle (if any)

Reimplemented in OpenSim::RigidTendonMuscle, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

virtual double OpenSim::Muscle::getActivation ( const SimTK::State & s ) const

virtual

get the activation level of the muscle, which modulates the active force of the muscle and has a normalized (0 to 1) value TODO: virtual to allow override by deprecated muscles.

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getActiveFiberForce ( const SimTK::State & s ) const

get the current active fiber force (N) due to activation*force_length*force_velocity relationships

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getActiveFiberForceAlongTendon ( const SimTK::State & s ) const

get the current active fiber force (N) projected onto the tendon direction

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getActiveForceLengthMultiplier ( const SimTK::State & s ) const

get the active fiber (contractile element) force multiplier due to current fiber length

double OpenSim::Muscle::getExcitation ( const SimTK::State & s ) const

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getFiberActivePower ( const SimTK::State & s ) const

get the current active fiber power (W)

double OpenSim::Muscle::getFiberForce ( const SimTK::State & s ) const

get the current fiber force (N) applied to the tendon

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getFiberLength ( const SimTK::State & s ) const

get the current working fiber length (m) for the muscle

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getFiberLengthAlongTendon ( const SimTK::State & s ) const

get the current fiber length (m) projected (*cos(pennationAngle)) onto the tendon direction

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getFiberPassivePower ( const SimTK::State & s ) const

get the current passive fiber power (W)

double OpenSim::Muscle::getFiberPotentialEnergy ( const SimTK::State & s ) const

the potential energy (J) stored in the fiber due to its parallel elastic element

double OpenSim::Muscle::getFiberStiffness ( const SimTK::State & s ) const

get the current fiber stiffness (N/m) defined as the partial derivative of fiber force w.r.t.

fiber length

double OpenSim::Muscle::getFiberVelocity ( const SimTK::State & s ) const

get current fiber velocity (m/s) positive is lengthening

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, and OpenSim::Delp1990Muscle_Deprecated.

double OpenSim::Muscle::getFiberVelocityAlongTendon ( const SimTK::State & s ) const

get the current afiber velocity (m/s) projected onto the tendon direction

const FiberVelocityInfo& OpenSim::Muscle::getFiberVelocityInfo ( const SimTK::State & s ) const

protected

double OpenSim::Muscle::getForceVelocityMultiplier ( const SimTK::State & s ) const

get the dimensionless multiplier resulting from the fiber's force-velocity curve

bool OpenSim::Muscle::getIgnoreActivationDynamics ( const SimTK::State & s ) const

Get/set Modeling (runtime) option to ignore activation dynamics when

computing muscle dynamics.

This does not directly modify the persistent property value.

bool OpenSim::Muscle::getIgnoreTendonCompliance ( const SimTK::State & s ) const

Get/set Modeling (runtime) option to ignore tendon compliance when

computing muscle dynamics.

This does not directly modify the persistent property value.

double OpenSim::Muscle::getMaxContractionVelocity ( ) const

get/set the maximum contraction velocity of the fibers, in optimal fiber-lengths per second

double OpenSim::Muscle::getMaxIsometricForce ( ) const

get/set the maximum isometric force (in N) that the fibers can generate

const MuscleDynamicsInfo& OpenSim::Muscle::getMuscleDynamicsInfo ( const SimTK::State & s ) const

protected

const MuscleLengthInfo& OpenSim::Muscle::getMuscleLengthInfo ( const SimTK::State & s ) const

protected

Developer Access to intermediate values calculate by the muscle model.

double OpenSim::Muscle::getMusclePotentialEnergy ( const SimTK::State & s ) const

the total potential energy (J) stored in the muscle

double OpenSim::Muscle::getMusclePower ( const SimTK::State & s ) const

get the current muscle power (W)

double OpenSim::Muscle::getMuscleStiffness ( const SimTK::State & s ) const

get the current muscle stiffness (N/m) defined as the partial derivative of muscle force w.r.t.

muscle length

double OpenSim::Muscle::getNormalizedFiberLength ( const SimTK::State & s ) const

get the current normalized fiber length (fiber_length/optimal_fiber_length)

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getNormalizedFiberVelocity ( const SimTK::State & s ) const

get normalize fiber velocity (fiber_lengths/s / max_contraction_velocity)

double OpenSim::Muscle::getOptimalFiberLength ( ) const

get/set the optimal length (in m) of the muscle fibers (lumped as a single fiber)

double OpenSim::Muscle::getPassiveFiberForce ( const SimTK::State & s ) const

get the current passive fiber force (N) passive_force_length relationship

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getPassiveFiberForceAlongTendon ( const SimTK::State & s ) const

get the current passive fiber force (N) projected onto the tendon direction

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getPassiveForceMultiplier ( const SimTK::State & s ) const

get the passive fiber (parallel elastic element) force multiplier

double OpenSim::Muscle::getPennationAngle ( const SimTK::State & s ) const

get the current pennation angle (radians) between the fiber and tendon at the current fiber length

double OpenSim::Muscle::getPennationAngleAtOptimalFiberLength ( ) const

get/set the angle (in radians) between fibers at their optimal fiber length and the tendon

double OpenSim::Muscle::getPennationAngularVelocity ( const SimTK::State & s ) const

get pennation angular velocity (radians/s)

double OpenSim::Muscle::getStress ( const SimTK::State & s ) const

virtual

get the stress in the muscle (part of the Actuator interface as well)

Reimplemented from OpenSim::PathActuator.

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getTendonForce ( const SimTK::State & s ) const

get the current tendon force (N) applied to bones

Reimplemented in OpenSim::ContDerivMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getTendonLength ( const SimTK::State & s ) const

get the current tendon length (m) given the current joint angles and fiber length

Reimplemented in OpenSim::ActivationFiberLengthMuscle_Deprecated.

double OpenSim::Muscle::getTendonPotentialEnergy ( const SimTK::State & s ) const

the potential energy (J) stored in the tendon

double OpenSim::Muscle::getTendonPower ( const SimTK::State & s ) const

get the current tendon power (W)

double OpenSim::Muscle::getTendonSlackLength ( ) const

get/set the resting (slack) length (in m) of the tendon that is in series with the muscle fiber

double OpenSim::Muscle::getTendonStiffness ( const SimTK::State & s ) const

get the current tendon stiffness (N/m) defined as the partial derivative of tendon force w.r.t.

tendon length

double OpenSim::Muscle::getTendonStrain ( const SimTK::State & s ) const

get the current tendon strain (delta_l/tendon_slack_length is dimensionless)

double OpenSim::Muscle::getTendonVelocity ( const SimTK::State & s ) const

get the tendon velocity (m/s) positive is lengthening

void OpenSim::Muscle::initStateFromProperties ( SimTK::State & state ) const

overrideprotectedvirtual

Subclass should override; be sure to invoke Force::initStateFromProperties() at the

beginning of the overriding method.

Reimplemented from OpenSim::Force.

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle.

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	max_isometric_force	,
		double	,
		"Maximum isometric force that the fibers can generate"
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	optimal_fiber_length	,
		double	,
		"Optimal length of the muscle fibers"
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	tendon_slack_length	,
		double	,
		"Resting length of the tendon"
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	pennation_angle_at_optimal	,
		double	,
		"Angle between tendon and fibers at optimal fiber length expressed in radians"
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	max_contraction_velocity	,
		double	,
		"Maximum contraction velocity of the	fibers,
		in optimal fiberlengths/second"
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	ignore_tendon_compliance	,
		bool	,
		"Compute muscle dynamics ignoring tendon compliance. Tendon is assumed to be rigid."
	)

OpenSim::Muscle::OpenSim_DECLARE_PROPERTY	(	ignore_activation_dynamics	,
		bool	,
		"Compute muscle dynamics ignoring activation dynamics. Activation is equivalent to excitation."
	)

virtual void OpenSim::Muscle::setActivation	(	SimTK::State &	s,
		double	activation
	)		const

pure virtual

DEPRECATED: only for backward compatibility.

Implemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::ContDerivMuscle_Deprecated, OpenSim::ActivationFiberLengthMuscle_Deprecated, OpenSim::ActivationFiberLengthMuscle, and OpenSim::RigidTendonMuscle.

void OpenSim::Muscle::setExcitation	(	SimTK::State &	s,
		double	excitation
	)		const

set the excitation (control) for this muscle.

NOTE if controllers are connected to the muscle and are adding in their controls, and setExcitation is called after the model's computeControls(), then setExcitation will override the controller values. If called before computeControls, then controller value(s) are added to the excitation set here.

void OpenSim::Muscle::setIgnoreActivationDynamics	(	SimTK::State &	s,
		bool	ignore
	)		const

void OpenSim::Muscle::setIgnoreTendonCompliance	(	SimTK::State &	s,
		bool	ignore
	)		const

void OpenSim::Muscle::setMaxContractionVelocity ( double maxContractionVelocity )

void OpenSim::Muscle::setMaxIsometricForce ( double maxIsometricForce )

void OpenSim::Muscle::setOptimalFiberLength ( double optimalFiberLength )

void OpenSim::Muscle::setPennationAngleAtOptimalFiberLength ( double pennationAngle )

void OpenSim::Muscle::setPropertiesFromState ( const SimTK::State & state )

overrideprotectedvirtual

Subclass should override; be sure to invoke

Force::setPropertiesFromState() at the beginning of the overriding method.

Reimplemented from OpenSim::Force.

Reimplemented in OpenSim::Millard2012AccelerationMuscle, OpenSim::Millard2012EquilibriumMuscle, OpenSim::ActivationFiberLengthMuscle_Deprecated, and OpenSim::ActivationFiberLengthMuscle.

void OpenSim::Muscle::setTendonSlackLength ( double tendonSlackLength )

virtual void OpenSim::Muscle::updateGeometry ( const SimTK::State & s )

protectedvirtual

FiberVelocityInfo& OpenSim::Muscle::updFiberVelocityInfo ( const SimTK::State & s ) const

protected

MuscleDynamicsInfo& OpenSim::Muscle::updMuscleDynamicsInfo ( const SimTK::State & s ) const

protected

MuscleLengthInfo& OpenSim::Muscle::updMuscleLengthInfo ( const SimTK::State & s ) const

protected

Member Data Documentation

double OpenSim::Muscle::_maxIsometricForce

protected

to support deprecated muscles

double OpenSim::Muscle::_muscleWidth

protected

The assumed fixed muscle-width from which the fiber pennation angle is calculated.

double OpenSim::Muscle::_optimalFiberLength

protected

double OpenSim::Muscle::_pennationAngleAtOptimal

protected

double OpenSim::Muscle::_tendonSlackLength

protected

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

E:/Projects/OpenSim30Br/OpenSim30/OpenSim/Simulation/Model/Muscle.h

Classes

Public Member Functions

Overriding forces

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation