An OpenSim Joint is an OpenSim::ModelComponent which connects two PhysicalFrames together and specifies their relative permissible motion as described in internal coordinates. More...

Inheritance diagram for OpenSim::Joint:

OpenSim Properties, Sockets, Outputs, Inputs
Properties (list)
Coordinate	coordinates
	"List containing the generalized coordinates (q's) that parameterize " "this joint." More...

PhysicalOffsetFrame	frames
	"Physical offset frames owned by the Joint that are typically used to " "satisfy the owning Joint's parent and child frame connections " "(sockets). PhysicalOffsetFrames are often used to describe the fixed " "transformation from a Body's origin to another location of interest " "on the Body (e.g., the joint center). When the joint is deleted, so " "are the PhysicalOffsetFrame components in this list." More...

Sockets
PhysicalFrame	parent_frame
	"The parent frame for the joint." More...

PhysicalFrame	child_frame
	"The child frame for the joint." More...

Outputs
double	power
	Provides the value of calcPower() and is available at stage SimTK::Stage::Acceleration . More...

SimTK::SpatialVec	reaction_on_parent
	Provides the value of calcReactionOnParentExpressedInGround() and is available at stage SimTK::Stage::Acceleration . More...

SimTK::SpatialVec	reaction_on_child
	Provides the value of calcReactionOnChildExpressedInGround() and is available at stage SimTK::Stage::Acceleration . 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
	Joint ()
	Default constructor. More...

	Joint (const std::string &name, const PhysicalFrame &parent, const PhysicalFrame &child)
	Convenience constructor. More...

	Joint (const std::string &name, const PhysicalFrame &parent, const SimTK::Vec3 &locationInParent, const SimTK::Vec3 &orientationInParent, const PhysicalFrame &child, const SimTK::Vec3 &locationInChild, const SimTK::Vec3 &orientationInChild)
	Backwards-compatible convenience constructor. More...

virtual	~Joint ()

const PhysicalFrame &	getChildFrame () const
	Get the child joint frame. More...

const OpenSim::PhysicalFrame &	getParentFrame () const
	Get the parent frame to which this joint attaches. More...

const Coordinate &	getCoordinate () const
	Convenience method to get a const reference to the Coordinate associated with a single-degree-of-freedom Joint. More...

Coordinate &	updCoordinate ()
	Convenience method to get a writable reference to the Coordinate associated with a single-degree-of-freedom Joint. More...

int	numCoordinates () const

bool	isCoordinateUsed (const Coordinate &aCoordinate) const

void	addFrame (PhysicalOffsetFrame *frame)
	Add a frame to the frames property in this Joint. More...

SimTK::SpatialVec	calcEquivalentSpatialForce (const SimTK::State &state, const SimTK::Vector &mobilityForces) const
	Given some system mobility (generalized) forces, calculate the equivalent spatial body force for this Joint. More...

SimTK::SpatialVec	calcReactionOnParentExpressedInGround (const SimTK::State &state) const
	Joint Reaction forces. More...

SimTK::SpatialVec	calcReactionOnChildExpressedInGround (const SimTK::State &state) const
	Calculate the joint reaction force and moment acting on the child frame and expressed in Ground. More...

virtual double	calcPower (const SimTK::State &s) const
	Joints in general do not contribute power since the reaction space forces are orthogonal to the mobility space. More...

	SimTK_DEFINE_UNIQUE_INDEX_TYPE (CoordinateIndex)

Coordinate::MotionType	getMotionType (CoordinateIndex cix) const
	Get the MotionType for a Coordinate that this Joint has enabled by its CoordinateIndex (in the Joints list of Coordinates). More...

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Pin &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Slider &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Weld &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Universal &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Ball &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Ellipsoid &mobod) const

template<>
int	getNumMobilities (const SimTK::MobilizedBody::Free &mobod) const

Property-related functions
const Coordinate &	get_coordinates (int i) const
	Get the value of the i-th element of the coordinates property. More...

Coordinate &	upd_coordinates (int i)
	Get a writable reference to the i-th element of the coordinates property. More...

void	set_coordinates (int i, const Coordinate &value)
	Set the value of the i-th element of coordinates property. More...

int	append_coordinates (const Coordinate &value)
	Append an element to the coordinates property. More...

const PhysicalOffsetFrame &	get_frames (int i) const
	Get the value of the i-th element of the frames property. More...

PhysicalOffsetFrame &	upd_frames (int i)
	Get a writable reference to the i-th element of the frames property. More...

void	set_frames (int i, const PhysicalOffsetFrame &value)
	Set the value of the i-th element of frames property. More...

int	append_frames (const PhysicalOffsetFrame &value)
	Append an element to the frames property. More...

Socket-related functions
void	connectSocket_parent_frame (const Object &object)
	Connect the 'parent_frame' Socket to an object of type PhysicalFrame. More...

void	connectSocket_child_frame (const Object &object)
	Connect the 'child_frame' Socket to an object of type PhysicalFrame. 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 Model &	getModel () const
	Get a const reference to the Model this component is part of. More...

Model &	updModel ()
	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...

Component &	operator= (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...

void	addComponent (Component *subcomponent)
	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 Component &	getComponent (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)

Component &	updComponent (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 StateVariable *	traverseToStateVariable (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...

void	addToSystem (SimTK::MultibodySystem &system) const
	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 Object &	getConnectee (const std::string &name) const
	Get the connectee as an Object. More...

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

AbstractSocket &	updSocket (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...

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

AbstractInput &	updInput (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 AbstractOutput &	getOutput (const std::string &name) const
	Get the Output provided by this Component by name. More...

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

SimTK::IteratorRange< OutputConstIterator >	getOutputs () const
	Iterate through all Outputs of this component. 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<class T >
SimTK::CacheEntryIndex	getCacheVariableIndex (const CacheVariable< T > &cv) const
	Get the index of a Component's cache variable in the Subsystem for allocations. More...

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

template<class 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<class T >
const T &	getCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv) const
	Get the value of a cache variable allocated by this Component. More...

template<typename T >
void	setCacheVariableValue (const SimTK::State &state, const std::string &k, T value) const
	Set the value of a cache variable, identified by `name`, to a new value and mark the cache variable as valid. More...

template<typename T >
void	setCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv, T value) const
	Set the value of a cache variable to a new value and mark the cache variable as valid. More...

template<typename T >
T &	updCacheVariableValue (const SimTK::State &state, const std::string &name) const
	Returns a mutable reference to the value of a cache variable identified by `name`. More...

template<typename T >
T &	updCacheVariableValue (const SimTK::State &state, const CacheVariable< T > &cv) const
	Returns a mutable reference to the value of a cache variable. More...

bool	isCacheVariableValid (const SimTK::State &state, const std::string &name) const
	Returns true if the cache variable, identified by `name`, is valid. More...

template<class T >
bool	isCacheVariableValid (const SimTK::State &state, const CacheVariable< T > &cv) const
	Returns true if the cache variable is valid. More...

void	markCacheVariableValid (const SimTK::State &state, const std::string &name) const
	Marks the value of a cache variable, identified by `name`, as valid. More...

template<typename T >
void	markCacheVariableValid (const SimTK::State &state, const CacheVariable< T > &cv) const
	Marks the value of a cache variable as valid. More...

void	markCacheVariableInvalid (const SimTK::State &state, const std::string &name) const
	Marks the value of a cache variable, identified by `name`, as invalid. More...

template<class T >
void	markCacheVariableInvalid (const SimTK::State &state, const CacheVariable< T > &cv) const
	Marks the value of a cache variable as invalid. More...

const Component &	getOwner () const
	Access the owner of this Component. More...

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

const Component &	getRoot () 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...

Object &	operator= (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 AbstractProperty &	getPropertyByIndex (int propertyIndex) const
	Get a const reference to a property by its index number, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByIndex (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 AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByName (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...

PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...

const PropertySet &	getPropertySet () const

Public Types
typedef Joint	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
CoordinateIndex	constructCoordinate (Coordinate::MotionType mt, unsigned idx)
	A CoordinateIndex member is created by constructCoordinate(). More...

void	setMotionType (CoordinateIndex cix, Coordinate::MotionType mt)

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...

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

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

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

void	extendSetPropertiesFromState (const SimTK::State &state) override
	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...

const SimTK::MobilizedBodyIndex	getMobilizedBodyIndex (const Body &body) const

void	setChildMobilizedBodyIndex (SimTK::MobilizedBodyIndex index) const

void	setCoordinateMobilizedBodyIndex (Coordinate *aCoord, SimTK::MobilizedBodyIndex index) const

void	setCoordinateMobilizerQIndex (Coordinate *aCoord, int index) const

void	setCoordinateModel (Coordinate aCoord, Model aModel) const

void	updateFromXMLNode (SimTK::Xml::Element &aNode, int versionNumber) override
	Updating XML formating to latest revision. More...

SimTK::SpatialVec	calcEquivalentSpatialForceForMobilizedBody (const SimTK::State &s, const SimTK::MobilizedBodyIndex mbx, const SimTK::Vector &mobilityForces) const
	Calculate the equivalent spatial force, FB_G, acting on a mobilized body specified by index acting at its mobilizer frame B, expressed in ground. More...

const SimTK::Body &	getParentInternalRigidBody () const
	Return the equivalent (internal) SimTK::Rigid::Body for the parent/child OpenSim::Body. More...

const SimTK::Body &	getChildInternalRigidBody () const

template<typename T >
T	createMobilizedBody (SimTK::MultibodySystem &mbs) const
	Utility method for creating the underlying MobilizedBody of the desired type of the concrete Joint. More...

template<typename T >
T	createMobilizedBody (SimTK::MobilizedBody &inboard, const SimTK::Transform &inboardTransform, const SimTK::Body &outboard, const SimTK::Transform &outboardTransform, int &startingCoordinateIndex, const PhysicalFrame *physicalFrame=nullptr) const
	Utility method for creating an underlying MobilizedBody of the desired type. More...

int	assignSystemIndicesToBodyAndCoordinates (const SimTK::MobilizedBody &mobod, const OpenSim::PhysicalFrame *mobilized, const int &numMobilities, const int &startingCoordinateIndex) const
	Utility method to assign body and coordinate indices from the underlying MultibodySystem from a newly created MobilizedBody. 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...

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)

void	adoptSubcomponent (Component *subcomponent)
	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...

size_t	getNumAdoptedSubcomponents () const
	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 Component &	get_components (int i) const
	Get the value of the i-th element of the components property. More...

Component &	upd_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...

virtual void	extendAddComponent (Component *subcomponent)
	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	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	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...

void	addStateVariable (Component::StateVariable *stateVariable) const
	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...

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

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...

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...

template<class T >
CacheVariable< T >	addCacheVariable (std::string name, 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...

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...

template<class T >
void	checkPropertyValueIsPositive (const Property< T > &p) const
	Throw an exception if any of the property's values are not positive. More...

template<class T >
void	checkPropertyValueIsInSet (const Property< T > &p, const std::set< T > &set) const
	Throw an exception if any of the property's values are not in the provided set. More...

template<class T >
void	checkPropertyValueIsInRangeOrSet (const Property< T > &p, const T &lower, const T &upper, const std::set< T > &set) const
	Throw an exception if any of the property's values are neither in the provided range nor in the provided set. 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 XMLDocument *	getDocument () const
	Get a const pointer to the document (if any) associated with this object. More...

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

Protected Attributes
bool	isReversed = false

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...

Auto-generated functions
static Joint *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

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

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

Joint *	clone () const override=0
	Create a new heap-allocated copy of the concrete object to which this Object refers. More...

const std::string &	getConcreteClassName () const override=0
	Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

Additional Inherited Members
Static Public Member Functions inherited from OpenSim::ModelComponent
static ModelComponent *	safeDownCast (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 Component *	safeDownCast (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 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. 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 Object *	newInstanceOfType (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 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. More...

static const std::string &	getClassName ()
	Return the name of this class as a string; i.e., "Object". More...

static void	setSerializeAllDefaults (bool shouldSerializeDefaults)
	Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...

static bool	getSerializeAllDefaults ()
	Report the value of the "serialize all defaults" flag. More...

static bool	isKindOf (const char *type)
	Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...

static void	setDebugLevel (int newLevel)
	Set the amount of logging output. More...

static int	getDebugLevel ()
	Get the current setting of debug level. More...

static 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. 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...

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...

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. More...

#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. More...

#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>. More...

#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. More...

Detailed Description

An OpenSim Joint is an OpenSim::ModelComponent which connects two PhysicalFrames together and specifies their relative permissible motion as described in internal coordinates.

The base Joint specifies two frames (e.g. one per body), which the joint spans. The relative motion (including the # of coordinates) are defined by concrete Joints, which specify the permissible kinematics of a child joint frame (on a child body) with respect to a parent joint frame (on a parent body). The designation of parent and child are used only to identify the directionality of the joint and in which frame the joint coordinates are expressed.

For example, A PinJoint between a parent frame, P, and a child frame, B, has a coordinate value of zero when the two frames are aligned and positive coordinate values are the angle between the frames' X-axes given a positive Z-rotation of the child frame about the coincident Z-axis in the parent frame.

Note: the parent and child frames must be added to the model by the time you call initSystem() on the model.

Concrete Joints can specify relative translations and even coupled rotations and translations (see EllipsoidJoint and CustomJoint). For more details on how the underlying formulation supports coupled curvilinear joints, see "Minimal formulation of joint motion for biomechanisms", 2010 A Seth, M Sherman, P Eastman, S Delp; Nonlinear dynamics 62 (1), 291-303

C++ example

// Define a pin joint that attaches pendulum (an OpenSim::Body) to ground.
PinJoint* myPin = new PinJoint("pendulumToGround", myModel.getGround(),
                               pendulum);

Python example

# Define a ball joint between blockA and blockB.

abJoint = osim.BallJoint('JointName', blockA, blockB)

If you want to connect to an existing PhysicalFrame (e.g., a Body or Ground) but not to its origin, you can create and connect to a PhysicalOffsetFrame; the following convenience constructor does this for you:

C++ example

// Define a pin joint that attaches the end of pendulum to the ground origin.
PinJoint* myPin = new PinJoint("pendulumToGround",
                               myModel.getGround(),   //parent PhysicalFrame
                               Vec3(0),               //location in parent
                               Vec3(0),               //orientation in parent
                               pendulum,              //child PhysicalFrame
                               Vec3(0,-length/2.,0),  //location in child
                               Vec3(0));              //orientation in child

Author: Ajay Seth

Member Typedef Documentation

◆ Self

typedef Joint OpenSim::Joint::Self

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

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

◆ Super

typedef ModelComponent OpenSim::Joint::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.

Constructor & Destructor Documentation

◆ Joint() [1/3]

OpenSim::Joint::Joint ( )

Default constructor.

Create an unnamed Joint with parent and child frame sockets that are unsatisfied.

◆ Joint() [2/3]

OpenSim::Joint::Joint	(	const std::string &	name,
		const PhysicalFrame &	parent,
		const PhysicalFrame &	child
	)

Convenience constructor.

Create a Joint by specifying the parent and child frames.

Parameters

[in]	name	the name associated with this joint (should be unique from other joints in the same model)
[in]	parent	the parent PhysicalFrame to which this joint connects
[in]	child	the child PhysicalFrame to which this joint connects

◆ Joint() [3/3]

OpenSim::Joint::Joint	(	const std::string &	name,
		const PhysicalFrame &	parent,
		const SimTK::Vec3 &	locationInParent,
		const SimTK::Vec3 &	orientationInParent,
		const PhysicalFrame &	child,
		const SimTK::Vec3 &	locationInChild,
		const SimTK::Vec3 &	orientationInChild
	)

Backwards-compatible convenience constructor.

Construct a Joint where the parent and child frames are specified as well as the location and orientation of the parent and child frames in their respective physical frames.

Parameters

[in]	name	the name associated with this joint (should be unique from other joints in the same model)
[in]	parent	the parent PhysicalFrame to which this joint connects
[in]	locationInParent	Vec3 of the location of the joint in the parent frame.
[in]	orientationInParent	Vec3 of the XYZ body-fixed Euler angles of the joint frame orientation in the parent frame.
[in]	child	the child PhysicalFrame to which this joint connects
[in]	locationInChild	Vec3 of the location of the joint in the child frame.
[in]	orientationInChild	Vec3 of the XYZ body-fixed Euler angles of the joint frame orientation in the child frame.

◆ ~Joint()

virtual OpenSim::Joint::~Joint ( )

virtual

Member Function Documentation

◆ addFrame()

void OpenSim::Joint::addFrame ( PhysicalOffsetFrame * frame )

Add a frame to the frames property in this Joint.

The frame is adopted, and should have been dynamically allocated. Use this function instead of append_frames().

◆ append_coordinates()

int OpenSim::Joint::append_coordinates ( const Coordinate & value )

inline

Append an element to the coordinates property.

◆ append_frames()

int OpenSim::Joint::append_frames ( const PhysicalOffsetFrame & value )

inline

Append an element to the frames property.

◆ assign()

void OpenSim::Joint::assign ( Object & aObject )

inlineoverride

This allows copy assignment in the Java GUI.

Exceptions

Exception if the argument is not of type Joint.

◆ assignSystemIndicesToBodyAndCoordinates()

int OpenSim::Joint::assignSystemIndicesToBodyAndCoordinates	(	const SimTK::MobilizedBody &	mobod,
		const OpenSim::PhysicalFrame *	mobilized,
		const int &	numMobilities,
		const int &	startingCoordinateIndex
	)		const

protected

Utility method to assign body and coordinate indices from the underlying MultibodySystem from a newly created MobilizedBody.

Assign its mobilities to OpenSim::Coordinates that belong to this Joint and the body index to the Body being mobilized by this Joint. If the Body is NULL then we assume that we are constructing intermediate MobilizedBodies and indices are assigned to corresponding coordinates, but not to a Body. If a Body is provided we assume that Joint creator has provided the correct child (or parent, if reversed) body that has been mobilized. This method throws an exception if the mobilized Body is neither the Joint's parent or child.

◆ calcEquivalentSpatialForce()

SimTK::SpatialVec OpenSim::Joint::calcEquivalentSpatialForce	(	const SimTK::State &	state,
		const SimTK::Vector &	mobilityForces
	)		const

Given some system mobility (generalized) forces, calculate the equivalent spatial body force for this Joint.

Keep in mind that there are typically nm < 6 mobilities per joint with an infinite set of solutions that can map nm gen forces to 6 spatial force components (3 for torque + 3 for force). The solution returned provides the "most" effective force and torque in the joint frame. This means the smallest magnitude force and/or torque that will result in the same generalized force. If a generalized force is defined along/about a joint axis, then this should be evident in the reported results as a force or torque on the same axis. NOTE: Joints comprised of multiple mobilizers and/or constraints, should override this method and account for multiple internal components.

Parameters

state	containing the generalized coordinate and speed values
mobilityForces	for the system as computed by inverse dynamics, for example

Returns: spatial force, FB_G, acting on the body connected by this joint at its location B, expressed in ground.

◆ calcEquivalentSpatialForceForMobilizedBody()

SimTK::SpatialVec OpenSim::Joint::calcEquivalentSpatialForceForMobilizedBody	(	const SimTK::State &	s,
		const SimTK::MobilizedBodyIndex	mbx,
		const SimTK::Vector &	mobilityForces
	)		const

protected

Calculate the equivalent spatial force, FB_G, acting on a mobilized body specified by index acting at its mobilizer frame B, expressed in ground.

◆ calcPower()

virtual double OpenSim::Joint::calcPower ( const SimTK::State & s ) const

virtual

Joints in general do not contribute power since the reaction space forces are orthogonal to the mobility space.

However, when joint motion is prescribed, the internal forces that move the joint will do work. In that case, the power is non-zero and the supplied SimTK::State must already have been realized to Acceleration stage so that constraint forces are available.

◆ calcReactionOnChildExpressedInGround()

SimTK::SpatialVec OpenSim::Joint::calcReactionOnChildExpressedInGround ( const SimTK::State & state ) const

inline

Calculate the joint reaction force and moment acting on the child frame and expressed in Ground.

Parameters

[in] state containing the generalized coordinate and speed values

Returns: SpatialVec of reaction force, RP_G, acting on child frame, C, and expressed in ground, G.

References OpenSim::SimTK_DEFINE_UNIQUE_INDEX_TYPE().

◆ calcReactionOnParentExpressedInGround()

SimTK::SpatialVec OpenSim::Joint::calcReactionOnParentExpressedInGround ( const SimTK::State & state ) const

inline

Joint Reaction forces.

Calculate the joint reaction force and moment acting on the parent frame and expressed in Ground.

Parameters

[in] state containing the generalized coordinate and speed values

Returns: SpatialVec of reaction force, RP_G, acting on parent frame, P, and expressed in ground, G.

◆ clone()

Joint* OpenSim::Joint::clone ( ) const

overridepure virtual

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.

Implemented in OpenSim::ScapulothoracicJoint, OpenSim::CustomJoint, OpenSim::BallJoint, OpenSim::FreeJoint, OpenSim::EllipsoidJoint, OpenSim::PinJoint, OpenSim::UniversalJoint, OpenSim::GimbalJoint, OpenSim::PlanarJoint, OpenSim::SliderJoint, and OpenSim::WeldJoint.

◆ connectSocket_child_frame()

void OpenSim::Joint::connectSocket_child_frame ( const Object & object )

inline

Connect the 'child_frame' Socket to an object of type PhysicalFrame.

Call finalizeConnections() afterwards to update the socket's connectee path property. The reference to the connectee set here takes precedence over the connectee path property.

◆ connectSocket_parent_frame()

void OpenSim::Joint::connectSocket_parent_frame ( const Object & object )

inline

Connect the 'parent_frame' Socket to an object of type PhysicalFrame.

Call finalizeConnections() afterwards to update the socket's connectee path property. The reference to the connectee set here takes precedence over the connectee path property.

◆ constructCoordinate()

CoordinateIndex OpenSim::Joint::constructCoordinate	(	Coordinate::MotionType	mt,
		unsigned	idx
	)

protected

A CoordinateIndex member is created by constructCoordinate().

E.g.:

class My2DofJoint : public Joint {
public:
    enum class Coord: unsigned {
        RotationX,
        TranslationX
    };
private:
    CoordinateIndex rx{ constructCoordinate(Coordinate::MotionType::Rotational,
                        static_cast<unsigned>(Coord::RotationX)) };
    CoordinateIndex tx{ constructCoordinate(Coordinate::MotionType::Translational,
                        static_cast<unsigned>(Coord::TranslationX)) };
    ...
};

Utility for a derived Joint to add the Coordinates that correspond to the motion it permits. Derived Joints must construct as many Coordinates as are reflected by the underlying Mobilizer Qs. The index of the corresponding enumeration (enum) is required at construction to ensure the Joint's internal list of Coordinates is consistent with its interface; an exception is thrown if the Coordinates are not constructed in the same order as the enums have been defined.

◆ createMobilizedBody() [1/2]

template<typename T >

T OpenSim::Joint::createMobilizedBody ( SimTK::MultibodySystem & mbs ) const

inlineprotected

Utility method for creating the underlying MobilizedBody of the desired type of the concrete Joint.

It is templatized by the MobilizedBody type. Concrete class cannot override this method but can customize extendAddToSystem() instead of using this service. It assumes that the MobilizedBody is associated with the child body, unless the Joint is specified as reversed in which case the parent is the Body that is "mobilized". For more granularity as to which bodies are being interconnected internally, and to specify their joint (mobilizer) transforms use:

See also: createMobilizedBody(MobilizedBody& inboard, const SimTK::Transform& inboardTransform, ...). following this method.

References OpenSim::PhysicalFrame::getMobilizedBody().

◆ createMobilizedBody() [2/2]

template<typename T >

T OpenSim::Joint::createMobilizedBody	(	SimTK::MobilizedBody &	inboard,
		const SimTK::Transform &	inboardTransform,
		const SimTK::Body &	outboard,
		const SimTK::Transform &	outboardTransform,
		int &	startingCoordinateIndex,
		const PhysicalFrame *	physicalFrame = `nullptr`
	)		const

inlineprotected

Utility method for creating an underlying MobilizedBody of the desired type.

Method is templatized by the MobilizedBody. Unlike the previous method, the inboard and outboard of the mobilized body are not assumed to be parent and child of the joint. This enables Joint component makers to introduce intermediate MobilizedBodies for the purpose of creating more complex Joints. If more than one MobilizedBody is being created, it is up to the caller to supply the corresponding coordinateIndex for the purpose of automatically assigning indices necessary for the Coordinates of this Joint to access the coordinates and speed values from the state of the MultibodySystem. As a convenience the startingCoorinateIndex is updated so that sequential calls will increment correctly based on the number of mobilities the concrete MobilizedBody enables.

Parameters

[in]	inboard	an existing SimTK::MobilizedBody in the multibody tree
[in]	inboardTransform	the transform locating the joint (mobilizer) frame on the inboard body
[in]	outboard	a SimTK::Rigid::Body to be added to the multibody tree
[in]	outboardTransform	the transform locating the joint (mobilizer) frame on the outboard body
[in,out]	startingCoordinateIndex	the starting index of mobilities enabled by the created MobilizedBody and used to assign mobility indices to the Joint's coordinates. It is incremented by the number of mobilities of the MobilizedBody created
[in]	physicalFrame	(optional) the PhysicalFrame associated with the MobilizeBody. The MobilizedBody index is assigned to the associated Body.

◆ extendAddToSystem()

void OpenSim::Joint::extendAddToSystem ( SimTK::MultibodySystem & system ) const

overrideprotectedvirtual

Add appropriate Simbody elements (if needed) to the System corresponding to this component and specify needed state resources.

extendAddToSystem() is called when the Simbody System is being created to represent a completed system (model) for computation. That is, connect() will already have been invoked on all components before any addToSystem() call is made. Helper methods for adding modeling options, state variables and their derivatives, discrete variables, and cache entries are available and can be called within extendAddToSystem() only.

Note that this method is const; you may not modify your model component or the containing model during this call. Any modifications you need should instead be performed in finalizeFromProperties() or at the latest connect(), which are non-const. The only exception is that you may need to record access information for resources you create in the system, such as an index number. For most Components, OpenSim base classes either provide convenience methods or handle indices automatically. Otherwise, you must declare indices as mutable data members so that you can set them here.

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

void MyComponent::extendAddToSystem(SimTK::MultibodySystem& system) const {
    // Perform any additions to the system required by your Super
    Super::extendAddToSystem(system);
    // ... your code goes here
}

This method assumes that this Component's addToSystem will be invoked before its subcomponents. If you need your subcomponents to be added to the system, first (e.g. require of a Force to be anchored to a SimTK::MobilizedBody specified by subcomponents) then you must implement: extendAddToSystemAfterSubcomponents(). It is possible to implement both method to add system elements before and then after your subcomponents have added themselves. Caution is required that Simbody elements are not added twice especially when order is unimportant.

Parameters

[in,out] system The MultibodySystem being added to.

See also: addModelingOption(), addStateVariable(), addDiscreteVariables(), addCacheVariable()

Reimplemented from OpenSim::Component.

Reimplemented in OpenSim::ScapulothoracicJoint, OpenSim::PlanarJoint, OpenSim::UniversalJoint, OpenSim::PinJoint, OpenSim::SliderJoint, and OpenSim::WeldJoint.

◆ extendConnectToModel()

void OpenSim::Joint::extendConnectToModel ( Model & model )

overrideprotectedvirtual

Perform any necessary initializations required to connect the component into the Model, and check for error conditions.

extendConnectToModel() is invoked on all components to complete construction of a Model, prior to creating a Simbody System to represent it computationally. It may also be invoked at times just for its error-checking side effects.

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

void MyComponent::extendConnectToModel(Model& model) {
    Super::extendConnectToModel(model); // invoke parent class method
    // ... your code goes here
}

Note that this method is expected to check for modeling errors and should throw an OpenSim::Exception if there is something wrong. For example, if your model component references another object by name, you should verify that it exists in the supplied Model, which is not guaranteed since components may be independently instantiated or constructed from XML files.

Parameters

[in,out] model The Model currently being constructed to which this ModelComponent should be connected.

Reimplemented from OpenSim::ModelComponent.

◆ extendFinalizeFromProperties()

void OpenSim::Joint::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::ModelComponent.

◆ extendInitStateFromProperties()

void OpenSim::Joint::extendInitStateFromProperties ( SimTK::State & state ) const

overrideprotectedvirtual

Transfer property values or other state-independent initial values into this component's state variables in the passed-in state argument.

This is called after a SimTK::System and State have been created for the Model (that is, after extendAddToSystem() has been called on all components). You should override this method if your component has properties (serializable values) that can affect initial values for your state variables. You can also perform any other state-independent calculations here that result in state initial conditions.

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

void MyComponent::extendInitStateFromProperties(SimTK::State& state) const {
    Super::extendInitStateFromProperties(state); // invoke parent class method
    // ... your code goes here
}

Parameters

state The state that will receive the new initial conditions.

See also: extendSetPropertiesFromState()

Reimplemented from OpenSim::Component.

◆ extendSetPropertiesFromState()

void OpenSim::Joint::extendSetPropertiesFromState ( const SimTK::State & state )

overrideprotectedvirtual

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.

Thus, state variable values can persist as part of the model component and be serialized as a property.

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

void MyComponent::extendSetPropertiesFromState(const SimTK::State& state) {
    Super::extendSetPropertiesFromState(state); // invoke parent class method
    // ... your code goes here
}

Parameters

state The State from which values may be extracted to set persistent property values.

See also: extendInitStateFromProperties()

Reimplemented from OpenSim::Component.

◆ get_coordinates()

const Coordinate& OpenSim::Joint::get_coordinates ( int i ) const

inline

Get the value of the i-th element of the coordinates property.

◆ get_frames()

const PhysicalOffsetFrame& OpenSim::Joint::get_frames ( int i ) const

inline

Get the value of the i-th element of the frames property.

◆ getChildFrame()

const PhysicalFrame& OpenSim::Joint::getChildFrame ( ) const

Get the child joint frame.

Returns: const PhysicalFrame reference.

◆ getChildInternalRigidBody()

const SimTK::Body& OpenSim::Joint::getChildInternalRigidBody ( ) const

protected

◆ getClassName()

static const std::string& OpenSim::Joint::getClassName ( )

inlinestatic

This returns "Joint".

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::Joint::getConcreteClassName ( ) const

overridepure virtual

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

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

See also: getClassName()

Implements OpenSim::ModelComponent.

Implemented in OpenSim::ScapulothoracicJoint, OpenSim::CustomJoint, OpenSim::BallJoint, OpenSim::FreeJoint, OpenSim::EllipsoidJoint, OpenSim::PinJoint, OpenSim::UniversalJoint, OpenSim::GimbalJoint, OpenSim::PlanarJoint, OpenSim::SliderJoint, and OpenSim::WeldJoint.

◆ getCoordinate()

const Coordinate& OpenSim::Joint::getCoordinate ( ) const

Convenience method to get a const reference to the Coordinate associated with a single-degree-of-freedom Joint.

If the Joint has more than one Coordinate, you must use get_coordinates() or provide the appropriate argument to the getCoordinate() method defined in the derived class.

Referenced by OpenSim::CustomJoint::updSpatialTransform().

◆ getMobilizedBodyIndex()

const SimTK::MobilizedBodyIndex OpenSim::Joint::getMobilizedBodyIndex ( const Body & body ) const

protected

const OpenSim::PhysicalFrame& OpenSim::Joint::getParentFrame ( ) const

Get the parent frame to which this joint attaches.

Returns: const ref to parent PhysicalFrame.

◆ getParentInternalRigidBody()

const SimTK::Body& OpenSim::Joint::getParentInternalRigidBody ( ) const

protected

Return the equivalent (internal) SimTK::Rigid::Body for the parent/child OpenSim::Body.

Not valid until after extendAddToSystem on the Body has been called.

◆ isCoordinateUsed()

bool OpenSim::Joint::isCoordinateUsed ( const Coordinate & aCoordinate ) const

◆ numCoordinates()

int OpenSim::Joint::numCoordinates ( ) const

inline

◆ safeDownCast()

static Joint* OpenSim::Joint::safeDownCast ( OpenSim::Object * obj )

inlinestatic

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

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

◆ set_coordinates()

void OpenSim::Joint::set_coordinates	(	int	i,
		const Coordinate &	value
	)

inline

Set the value of the i-th element of coordinates property.

◆ set_frames()

void OpenSim::Joint::set_frames	(	int	i,
		const PhysicalOffsetFrame &	value
	)

inline

Set the value of the i-th element of frames property.

◆ setChildMobilizedBodyIndex()

void OpenSim::Joint::setChildMobilizedBodyIndex ( SimTK::MobilizedBodyIndex index ) const

protected

◆ setCoordinateMobilizedBodyIndex()

void OpenSim::Joint::setCoordinateMobilizedBodyIndex	(	Coordinate *	aCoord,
		SimTK::MobilizedBodyIndex	index
	)		const

inlineprotected

◆ setCoordinateMobilizerQIndex()

void OpenSim::Joint::setCoordinateMobilizerQIndex	(	Coordinate *	aCoord,
		int	index
	)		const

inlineprotected

◆ setCoordinateModel()

void OpenSim::Joint::setCoordinateModel	(	Coordinate *	aCoord,
		Model *	aModel
	)		const

inlineprotected

References OpenSim::ModelComponent::_model.

◆ setMotionType()

void OpenSim::Joint::setMotionType	(	CoordinateIndex	cix,
		Coordinate::MotionType	mt
	)

protected

◆ SimTK_DEFINE_UNIQUE_INDEX_TYPE()

OpenSim::Joint::SimTK_DEFINE_UNIQUE_INDEX_TYPE ( CoordinateIndex )

◆ upd_coordinates()

Coordinate& OpenSim::Joint::upd_coordinates ( int i )

inline

Get a writable reference to the i-th element of the coordinates property.

◆ upd_frames()

PhysicalOffsetFrame& OpenSim::Joint::upd_frames ( int i )

inline

Get a writable reference to the i-th element of the frames property.

◆ updateFromXMLNode()

void OpenSim::Joint::updateFromXMLNode	(	SimTK::Xml::Element &	aNode,
		int	versionNumber
	)

overrideprotectedvirtual

Updating XML formating to latest revision.

Reimplemented from OpenSim::ModelComponent.

◆ updCoordinate()

Coordinate& OpenSim::Joint::updCoordinate ( )

Convenience method to get a writable reference to the Coordinate associated with a single-degree-of-freedom Joint.

If the Joint has more than one Coordinate, you must use upd_coordinates() or provide the appropriate argument to the updCoordinate() method defined in the derived class.

Referenced by OpenSim::CustomJoint::updSpatialTransform().

Member Data Documentation

◆ isReversed

bool OpenSim::Joint::isReversed = false

protected

OpenSim Property, Socket, Output, Input Documentation

◆ child_frame

PhysicalFrame OpenSim::Joint::child_frame

"The child frame for the joint."

In an XML file, you can set this Socket's connectee path via the <socket_child_frame > element. This socket was generated with the OpenSim_DECLARE_SOCKET macro; see AbstractSocket for more information.

See also: connectSocket_child_frame()

◆ coordinates

Coordinate OpenSim::Joint::coordinates

"List containing the generalized coordinates (q's) that parameterize " "this joint."

This property appears in XML files under the tag <coordinates>. This property holds a list of objects, and was generated with the OpenSim_DECLARE_LIST_PROPERTY macro; see Property to learn about the property system.

See also: get_coordinates(), upd_coordinates(), set_coordinates(), append_coordinates()

◆ frames

PhysicalOffsetFrame OpenSim::Joint::frames

"Physical offset frames owned by the Joint that are typically used to " "satisfy the owning Joint's parent and child frame connections " "(sockets). PhysicalOffsetFrames are often used to describe the fixed " "transformation from a Body's origin to another location of interest " "on the Body (e.g., the joint center). When the joint is deleted, so " "are the PhysicalOffsetFrame components in this list."

This property appears in XML files under the tag <frames>. This property holds a list of objects, and was generated with the OpenSim_DECLARE_LIST_PROPERTY macro; see Property to learn about the property system.

See also: get_frames(), upd_frames(), set_frames(), append_frames()

◆ parent_frame

PhysicalFrame OpenSim::Joint::parent_frame

"The parent frame for the joint."

In an XML file, you can set this Socket's connectee path via the <socket_parent_frame > element. This socket was generated with the OpenSim_DECLARE_SOCKET macro; see AbstractSocket for more information.

See also: connectSocket_parent_frame()

◆ power

double OpenSim::Joint::power

Provides the value of calcPower() and is available at stage SimTK::Stage::Acceleration .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

◆ reaction_on_child

SimTK::SpatialVec OpenSim::Joint::reaction_on_child

Provides the value of calcReactionOnChildExpressedInGround() and is available at stage SimTK::Stage::Acceleration .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

◆ reaction_on_parent

SimTK::SpatialVec OpenSim::Joint::reaction_on_parent

Provides the value of calcReactionOnParentExpressedInGround() and is available at stage SimTK::Stage::Acceleration .

This output was generated with the OpenSim_DECLARE_OUTPUT macro.

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

OpenSim/Simulation/SimbodyEngine/Joint.h

OpenSim Properties, Sockets, Outputs, Inputs

Public Member Functions

Public Types

Protected Member Functions

Protected Attributes

Auto-generated functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Self

◆ Super

Constructor & Destructor Documentation

◆ Joint() [1/3]

◆ Joint() [2/3]

◆ Joint() [3/3]

◆ ~Joint()

Member Function Documentation

◆ addFrame()

◆ append_coordinates()

◆ append_frames()

◆ assign()

◆ assignSystemIndicesToBodyAndCoordinates()

◆ calcEquivalentSpatialForce()

◆ calcEquivalentSpatialForceForMobilizedBody()

◆ calcPower()

◆ calcReactionOnChildExpressedInGround()

◆ calcReactionOnParentExpressedInGround()

◆ clone()

◆ connectSocket_child_frame()

◆ connectSocket_parent_frame()

◆ constructCoordinate()

◆ createMobilizedBody() [1/2]

◆ createMobilizedBody() [2/2]

◆ extendAddToSystem()

◆ extendConnectToModel()

◆ extendFinalizeFromProperties()

◆ extendInitStateFromProperties()

◆ extendSetPropertiesFromState()

◆ get_coordinates()

◆ get_frames()

◆ getChildFrame()

◆ getChildInternalRigidBody()

◆ getClassName()

◆ getConcreteClassName()

◆ getCoordinate()

◆ getMobilizedBodyIndex()

◆ getMotionType()

◆ getNumMobilities() [1/7]

◆ getNumMobilities() [2/7]

◆ getNumMobilities() [3/7]

◆ getNumMobilities() [4/7]

◆ getNumMobilities() [5/7]

◆ getNumMobilities() [6/7]

◆ getNumMobilities() [7/7]

◆ getParentFrame()

◆ getParentInternalRigidBody()

◆ isCoordinateUsed()

◆ numCoordinates()

◆ safeDownCast()

◆ set_coordinates()

◆ set_frames()

◆ setChildMobilizedBodyIndex()

◆ setCoordinateMobilizedBodyIndex()

◆ setCoordinateMobilizerQIndex()

◆ setCoordinateModel()

◆ setMotionType()

◆ SimTK_DEFINE_UNIQUE_INDEX_TYPE()

◆ upd_coordinates()

◆ upd_frames()

◆ updateFromXMLNode()

◆ updCoordinate()

Member Data Documentation

◆ isReversed

OpenSim Property, Socket, Output, Input Documentation

◆ child_frame

◆ coordinates

◆ frames

◆ parent_frame

◆ power

◆ reaction_on_child