API  4.1
For C++ developers
OpenSim::Joint Class Referenceabstract

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 PhysicalFramegetChildFrame () const
 Get the child joint frame. More...
 
const OpenSim::PhysicalFramegetParentFrame () const
 Get the parent frame to which this joint attaches. More...
 
const CoordinategetCoordinate () const
 Convenience method to get a const reference to the Coordinate associated with a single-degree-of-freedom Joint. More...
 
CoordinateupdCoordinate ()
 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 Coordinateget_coordinates (int i) const
 Get the value of the i-th element of the coordinates property. More...
 
Coordinateupd_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 PhysicalOffsetFrameget_frames (int i) const
 Get the value of the i-th element of the frames property. More...
 
PhysicalOffsetFrameupd_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 ModelgetModel () const
 Get a const reference to the Model this component is part of. More...
 
ModelupdModel ()
 Get a modifiable reference to the Model this component is part of. More...
 
bool hasModel () const
 Does this ModelComponent have a Model associated with it? More...
 
void preScale (const SimTK::State &s, const ScaleSet &scaleSet)
 Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...
 
void scale (const SimTK::State &s, const ScaleSet &scaleSet)
 Scale the ModelComponent. More...
 
void postScale (const SimTK::State &s, const ScaleSet &scaleSet)
 Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...
 
void assign (Object &aObject) override
 This allows copy assignment in the Java GUI. More...
 
- Public Member Functions inherited from OpenSim::Component
 Component ()
 Default constructor. More...
 
 Component (const std::string &aFileName, bool aUpdateFromXMLNode=true)
 Construct Component from an XML file. More...
 
 Component (SimTK::Xml::Element &aNode)
 Construct Component from a specific node in an XML document. More...
 
 Component (const Component &)=default
 Use default copy constructor and assignment operator. More...
 
Componentoperator= (const Component &)=default
 
virtual ~Component ()=default
 Destructor is virtual to allow concrete Component to cleanup. More...
 
virtual void generateDecorations (bool fixed, const ModelDisplayHints &hints, const SimTK::State &state, SimTK::Array_< SimTK::DecorativeGeometry > &appendToThis) const
 Optional method for generating arbitrary display geometry that reflects this Component at the specified state. More...
 
const SimTK::MultibodySystem & getSystem () const
 Get the underlying MultibodySystem that this component is connected to. More...
 
bool hasSystem () const
 Check if this component has an underlying MultibodySystem. More...
 
bool isComponentInOwnershipTree (const Component *component) const
 Does the provided component already exist anywhere in the ownership tree (not just subcomponents of this component)? More...
 
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 ComponentgetComponent (const std::string &pathname) const
 Similar to the templatized getComponent(), except this returns the component as the generic Component type. More...
 
template<class C = Component>
C & updComponent (const std::string &name)
 Get a writable reference to a subcomponent. More...
 
template<class C = Component>
C & updComponent (const ComponentPath &name)
 
ComponentupdComponent (const std::string &pathname)
 Similar to the templatized updComponent(), except this returns the component as the generic Component type. More...
 
unsigned printComponentsMatching (const std::string &substring) const
 Print a list to the console of all components whose absolute path name contains the given string. More...
 
int getNumStateVariables () const
 Get the number of "continuous" state variables maintained by the Component and its subcomponents. More...
 
Array< std::string > getStateVariableNames () const
 Get the names of "continuous" state variables maintained by the Component and its subcomponents. More...
 
template<class C = Component>
const C * findComponent (const ComponentPath &pathToFind) const
 Find a Component to which this Component is an ancestor—in other words, a Component that is directly owned by this Component or is owned by one of its sub-components, sub-sub-components, etc. More...
 
template<class C = Component>
const C * findComponent (const std::string &pathToFind) const
 Same as findComponent(const ComponentPath&), but accepting a string (a path or just a name) as input. More...
 
const StateVariabletraverseToStateVariable (const std::string &pathName) const
 Get a StateVariable anywhere in the Component tree, given a StateVariable path. More...
 
void finalizeFromProperties ()
 Define a Component's internal data members and structure according to its properties. More...
 
void finalizeConnections (Component &root)
 Satisfy the Component's connections specified by its Sockets and Inputs. More...
 
void clearConnections ()
 Disconnect/clear this Component from its aggregate component. More...
 
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 ObjectgetConnectee (const std::string &name) const
 Get the connectee as an Object. More...
 
const AbstractSocketgetSocket (const std::string &name) const
 Get an AbstractSocket for the given socket name. More...
 
AbstractSocketupdSocket (const std::string &name)
 Get a writable reference to the AbstractSocket for the given socket name. More...
 
template<typename T >
const Socket< T > & getSocket (const std::string &name) const
 Get a const reference to the concrete Socket provided by this Component by name. More...
 
template<typename T >
Socket< T > & updSocket (const std::string &name)
 Get a writable reference to the concrete Socket provided by this Component by name. More...
 
int getModelingOption (const SimTK::State &state, const std::string &name) const
 Get a ModelingOption flag for this Component by name. More...
 
void setModelingOption (SimTK::State &state, const std::string &name, int flag) const
 Set the value of a ModelingOption flag for this Component. More...
 
template<typename T >
const T & getInputValue (const SimTK::State &state, const std::string &name) const
 Get the Input value that this component is dependent on. More...
 
template<typename T >
const T & getOutputValue (const SimTK::State &state, const std::string &name) const
 Get the Output value provided by this Component by name. More...
 
double getStateVariableValue (const SimTK::State &state, const std::string &name) const
 Get the value of a state variable allocated by this Component. More...
 
void setStateVariableValue (SimTK::State &state, const std::string &name, double value) const
 Set the value of a state variable allocated by this Component by name. More...
 
SimTK::Vector getStateVariableValues (const SimTK::State &state) const
 Get all values of the state variables allocated by this Component. More...
 
void setStateVariableValues (SimTK::State &state, const SimTK::Vector &values) const
 Set all values of the state variables allocated by this Component. More...
 
double getStateVariableDerivativeValue (const SimTK::State &state, const std::string &name) const
 Get the value of a state variable derivative computed by this Component. More...
 
double getDiscreteVariableValue (const SimTK::State &state, const std::string &name) const
 Get the value of a discrete variable allocated by this Component by name. More...
 
void setDiscreteVariableValue (SimTK::State &state, const std::string &name, double value) const
 Set the value of a discrete variable allocated by this Component by name. More...
 
template<typename T >
const T & getCacheVariableValue (const SimTK::State &state, const std::string &name) const
 Get the value of a cache variable allocated by this Component by name. More...
 
template<typename T >
T & updCacheVariableValue (const SimTK::State &state, const std::string &name) const
 Obtain a writable cache variable value allocated by this Component by name. More...
 
void markCacheVariableValid (const SimTK::State &state, const std::string &name) const
 After updating a cache variable value allocated by this Component, you can mark its value as valid, which will not change until the realization stage falls below the minimum set at the time the cache variable was created. More...
 
void markCacheVariableInvalid (const SimTK::State &state, const std::string &name) const
 Mark a cache variable value allocated by this Component as invalid. More...
 
bool isCacheVariableValid (const SimTK::State &state, const std::string &name) const
 Enables the user to monitor the validity of the cache variable value using the returned flag. More...
 
template<typename T >
void setCacheVariableValue (const SimTK::State &state, const std::string &name, const T &value) const
 Set cache variable value allocated by this Component by name. More...
 
void printSubcomponentInfo () const
 List all subcomponents by name and recurse into these components to list their subcomponents, and so on. More...
 
void printSocketInfo () const
 List all the Sockets of this component and whether or not they are connected. More...
 
void printInputInfo () const
 List all the inputs of this component and whether or not they are connected. More...
 
template<typename C >
void printSubcomponentInfo () const
 
void printOutputInfo (const bool includeDescendants=true) const
 Print outputs of this component and optionally, those of all subcomponents. More...
 
void assign (Object &aObject) override
 This allows copy assignment in the Java GUI. More...
 
int getNumInputs () const
 Access the number of Inputs that this component has. More...
 
int getNumOutputs () const
 Access the number of Outputs that this component has. More...
 
std::vector< std::string > getInputNames () const
 Collect and return the names of Inputs in this component as an std::vector. More...
 
std::vector< std::string > getOutputNames () const
 Collect and return the names of Outputs in this component as an std::vector. More...
 
const AbstractInputgetInput (const std::string &name) const
 Get an Input provided by this Component by name. More...
 
AbstractInputupdInput (const std::string &name)
 Get a writable reference to an Input provided by this Component by name. More...
 
template<typename T >
const Input< T > & getInput (const std::string &name) const
 Get a concrete Input that you can directly ask for its values. More...
 
const AbstractOutputgetOutput (const std::string &name) const
 Get the Output provided by this Component by name. More...
 
AbstractOutputupdOutput (const std::string &name)
 Get a writable reference to an Output provided by this Component by name. More...
 
SimTK::IteratorRange< OutputConstIteratorgetOutputs () const
 Iterate through all Outputs of this component. More...
 
const ComponentgetOwner () const
 Access the owner of this Component. More...
 
bool hasOwner () const
 (For advanced users) Check if this Component has an owner. More...
 
const ComponentgetRoot () const
 Obtain the root Component, which is this component if it is orphaned. More...
 
- Public Member Functions inherited from OpenSim::Object
virtual ~Object ()
 Virtual destructor for cleanup. More...
 
bool isEqualTo (const Object &aObject) const
 Equality operator wrapper for use from languages not supporting operator overloading. More...
 
Objectoperator= (const Object &aObject)
 Copy assignment copies he base class fields, including the properties. More...
 
virtual bool operator== (const Object &aObject) const
 Determine if two objects are equal. More...
 
virtual bool operator< (const Object &aObject) const
 Provide an ordering for objects so they can be put in sorted containers. More...
 
void setName (const std::string &name)
 Set the name of the Object. More...
 
const std::string & getName () const
 Get the name of this Object. More...
 
void setDescription (const std::string &description)
 Set description, a one-liner summary. More...
 
const std::string & getDescription () const
 Get description, a one-liner summary. More...
 
const std::string & getAuthors () const
 Get Authors of this Object. More...
 
void setAuthors (const std::string &authors)
 Set Authors of this object. More...
 
const std::string & getReferences () const
 Get references or publications to cite if using this object. More...
 
void setReferences (const std::string &references)
 Set references or publications to cite if using this object. More...
 
int getNumProperties () const
 Determine how many properties are stored with this Object. More...
 
const AbstractPropertygetPropertyByIndex (int propertyIndex) const
 Get a const reference to a property by its index number, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByIndex (int propertyIndex)
 Get a writable reference to a property by its index number, returned as an AbstractProperty. More...
 
bool hasProperty (const std::string &name) const
 Return true if this Object has a property of any type with the given name, which must not be empty. More...
 
const AbstractPropertygetPropertyByName (const std::string &name) const
 Get a const reference to a property by its name, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByName (const std::string &name)
 Get a writable reference to a property by its name, returned as an AbstractProperty. More...
 
template<class T >
bool hasProperty () const
 Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...
 
template<class T >
const Property< T > & getProperty (const PropertyIndex &index) const
 Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...
 
template<class T >
Property< T > & updProperty (const PropertyIndex &index)
 Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...
 
bool isObjectUpToDateWithProperties () const
 Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...
 
void readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
 We're given an XML element from which we are to populate this Object. More...
 
void updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
 Serialize this object into the XML node that represents it. More...
 
bool getInlined () const
 Inlined means an in-memory Object that is not associated with an XMLDocument. More...
 
void setInlined (bool aInlined, const std::string &aFileName="")
 Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...
 
std::string getDocumentFileName () const
 If there is a document associated with this object then return the file name maintained by the document. More...
 
int getDocumentFileVersion () const
 If there is a document associated with this object then return its version number. More...
 
void setAllPropertiesUseDefault (bool aUseDefault)
 
bool print (const std::string &fileName) const
 Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...
 
std::string dump () const
 dump the XML representation of this Object into an std::string and return it. More...
 
virtual bool isA (const char *type) const
 The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...
 
const std::string & toString () const
 Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...
 
PropertySetgetPropertySet ()
 OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...
 
const PropertySetgetPropertySet () const
 

Public Types

typedef 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 >
createMobilizedBody (SimTK::MultibodySystem &mbs) const
 Utility method for creating the underlying MobilizedBody of the desired type of the concrete Joint. More...
 
template<typename 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 Componentget_components (int i) const
 Get the value of the i-th element of the components property. More...
 
Componentupd_components (int i)
 Get a writable reference to the i-th element of the components property. More...
 
void set_components (int i, const Component &value)
 Set the value of the i-th element of components property. More...
 
int append_components (const Component &value)
 Append an element to the components property. More...
 
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...
 
template<class T >
void addCacheVariable (const std::string &cacheVariableName, const T &variablePrototype, SimTK::Stage dependsOnStage) const
 Add a state cache entry belonging to this Component to hold calculated values that must be automatically invalidated when certain state values change. More...
 
SimTK::MultibodySystem & updSystem () const
 Get writable reference to the MultibodySystem that this component is connected to. More...
 
const int getStateIndex (const std::string &name) const
 Get the index of a Component's continuous state variable in the Subsystem for allocations. More...
 
SimTK::SystemYIndex getStateVariableSystemIndex (const std::string &stateVariableName) const
 Get the System Index of a state variable allocated by this Component. More...
 
const SimTK::DiscreteVariableIndex getDiscreteVariableIndex (const std::string &name) const
 Get the index of a Component's discrete variable in the Subsystem for allocations. More...
 
const SimTK::CacheEntryIndex getCacheVariableIndex (const std::string &name) const
 Get the index of a Component's cache variable in the Subsystem for allocations. More...
 
template<typename T >
PropertyIndex constructSocket (const std::string &name, const std::string &propertyComment)
 Construct a specialized Socket for this Component's dependence on another Component. More...
 
template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
 Construct an output for a member function of the same component. More...
 
template<typename T , typename CompType = Component>
bool constructOutput (const std::string &name, const T &(CompType::*const memFunc)(const SimTK::State &) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
 This variant handles component member functions that return the output value by const reference (const T&). More...
 
template<typename T , typename CompType >
bool constructListOutput (const std::string &name, T(CompType::*const memFunc)(const SimTK::State &, const std::string &channel) const, const SimTK::Stage &dependsOn=SimTK::Stage::Acceleration)
 Construct an output that can have multiple channels. More...
 
bool constructOutputForStateVariable (const std::string &name)
 Construct an Output for a StateVariable. More...
 
template<typename T >
PropertyIndex constructInput (const std::string &name, bool isList, const std::string &propertyComment, const SimTK::Stage &requiredAtStage=SimTK::Stage::Instance)
 Construct an Input (socket) for this Component's dependence on an Output signal. More...
 
void setOwner (const Component &owner)
 Set this Component's reference to its owning Component More...
 
- Protected Member Functions inherited from OpenSim::Object
 Object ()
 The default constructor is only for use by constructors of derived types. More...
 
 Object (const std::string &fileName, bool aUpdateFromXMLNode=true)
 Constructor from a file, to be called from other constructors that take a file as input. More...
 
 Object (const Object &source)
 Copy constructor is invoked automatically by derived classes with default copy constructors; otherwise it must be invoked explicitly. More...
 
 Object (SimTK::Xml::Element &aElement)
 Construct the base class portion of an Object from a given Xml element that describes this Object. More...
 
template<class T >
PropertyIndex addProperty (const std::string &name, const std::string &comment, const T &value)
 Define a new single-value property of known type T, with the given name, associated comment, and initial value. More...
 
template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment)
 Add an optional property, meaning it can contain either no value or a single value. More...
 
template<class T >
PropertyIndex addOptionalProperty (const std::string &name, const std::string &comment, const T &value)
 Add an optional property, meaning it can contain either no value or a single value. More...
 
template<class T >
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize)
 Define a new list-valued property of known type T, with the given name, associated comment, minimum (==0) and maximum (>0) allowable list lengths, and a zero-length initial value. More...
 
template<class T , template< class > class Container>
PropertyIndex addListProperty (const std::string &name, const std::string &comment, int minSize, int maxSize, const Container< T > &valueList)
 Define a new list-valued property as above, but assigning an initial value via some templatized container class that supports size() and indexing. More...
 
PropertyIndex getPropertyIndex (const std::string &name) const
 Look up a property by name and return its PropertyIndex if it is found. More...
 
template<class T >
PropertyIndex getPropertyIndex () const
 Look up an unnamed property by the type of object it contains, and return its PropertyIndex if it is found. More...
 
void setObjectIsUpToDateWithProperties ()
 When an object is initialized using the current values of its properties, it can set a flag indicating that it is up to date. More...
 
void clearObjectIsUpToDateWithProperties ()
 For testing or debugging purposes, manually clear the "object is up to date with respect to properties" flag. More...
 
void makeObjectNamesConsistentWithProperties ()
 Make sure the name of an object is consistent with its property type. More...
 
void updateFromXMLDocument ()
 Use this method only if you're deserializing from a file and the object is at the top level; that is, primarily in constructors that take a file name as input. More...
 
void setDocument (XMLDocument *doc)
 Unconditionally set the XMLDocument associated with this object. More...
 
const XMLDocumentgetDocument () const
 Get a const pointer to the document (if any) associated with this object. More...
 
XMLDocumentupdDocument ()
 Get a writable pointer to the document (if any) associated with this object. More...
 

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 JointsafeDownCast (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...
 
Jointclone () 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 ModelComponentsafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
static const std::string & getClassName ()
 This returns "ModelComponent". More...
 
- Static Public Member Functions inherited from OpenSim::Component
static ComponentsafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
static const std::string & getClassName ()
 This returns "Component". More...
 
- Static Public Member Functions inherited from OpenSim::Object
static void registerType (const Object &defaultObject)
 Register an instance of a class; if the class is already registered it will be replaced. More...
 
static void renameType (const std::string &oldTypeName, const std::string &newTypeName)
 Support versioning by associating the current Object type with an old name. More...
 
static const ObjectgetDefaultInstanceOfType (const std::string &concreteClassName)
 Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More...
 
template<class T >
static bool isObjectTypeDerivedFrom (const std::string &concreteClassName)
 Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More...
 
static ObjectnewInstanceOfType (const std::string &concreteClassName)
 Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...
 
static void getRegisteredTypenames (Array< std::string > &typeNames)
 Retrieve all the typenames registered so far. More...
 
template<class T >
static void getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
 Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
 Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
 Same as the other signature but the class name and property name are provided as two separate strings. More...
 
static ObjectmakeObjectFromFile (const std::string &fileName)
 Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...
 
static const std::string & getClassName ()
 Return the name of this class as a string; i.e., "Object". More...
 
static void setSerializeAllDefaults (bool shouldSerializeDefaults)
 Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...
 
static bool getSerializeAllDefaults ()
 Report the value of the "serialize all defaults" flag. More...
 
static bool isKindOf (const char *type)
 Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...
 
static void setDebugLevel (int newLevel)
 Set the debug level to get verbose output. More...
 
static int getDebugLevel ()
 Get current setting of debug level. More...
 
static ObjectSafeCopy (const Object *aObject)
 Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...
 
static void RegisterType (const Object &defaultObject)
 OBSOLETE alternate name for registerType(). More...
 
static void RenameType (const std::string &oldName, const std::string &newName)
 OBSOLETE alternate name for renameType(). More...
 
- Static Public Attributes inherited from OpenSim::Object
static const std::string DEFAULT_NAME
 Name used for default objects when they are serialized. More...
 
- Static Protected Member Functions inherited from OpenSim::Component
static void prependComponentPathToConnecteePath (Component &subcomponent)
 For internal use. More...
 
- Static Protected Attributes inherited from OpenSim::ModelComponent
static const SimTK::Vec3 InvalidScaleFactors
 Returned by getScaleFactors() if the ScaleSet does not contain scale factors for the base Body associated with the specified Frame. More...
 

Detailed Description

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

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

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

◆ Super

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

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

This is generated by the OpenSim_DECLARE_*_OBJECT macros.

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]namethe name associated with this joint (should be unique from other joints in the same model)
[in]parentthe parent PhysicalFrame to which this joint connects
[in]childthe 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]namethe name associated with this joint (should be unique from other joints in the same model)
[in]parentthe parent PhysicalFrame to which this joint connects
[in]locationInParentVec3 of the location of the joint in the parent frame.
[in]orientationInParentVec3 of the XYZ body-fixed Euler angles of the joint frame orientation in the parent frame.
[in]childthe child PhysicalFrame to which this joint connects
[in]locationInChildVec3 of the location of the joint in the child frame.
[in]orientationInChildVec3 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
Exceptionif 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
statecontaining the generalized coordinate and speed values
mobilityForcesfor 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]statecontaining 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]statecontaining 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::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]inboardan existing SimTK::MobilizedBody in the multibody tree
[in]inboardTransformthe transform locating the joint (mobilizer) frame on the inboard body
[in]outboarda SimTK::Rigid::Body to be added to the multibody tree
[in]outboardTransformthe transform locating the joint (mobilizer) frame on the outboard body
[in,out]startingCoordinateIndexthe 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
// ... 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]systemThe MultibodySystem being added to.
See also
addModelingOption(), addStateVariable(), addDiscreteVariables(), addCacheVariable()

Reimplemented from OpenSim::Component.

Reimplemented in 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]modelThe 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
stateThe 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
stateThe 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::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

◆ getMotionType()

Coordinate::MotionType OpenSim::Joint::getMotionType ( CoordinateIndex  cix) const

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

◆ getNumMobilities() [1/7]

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

◆ getNumMobilities() [2/7]

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

◆ getNumMobilities() [3/7]

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

◆ getNumMobilities() [4/7]

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

◆ getNumMobilities() [5/7]

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

◆ getNumMobilities() [6/7]

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

◆ getNumMobilities() [7/7]

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

◆ getParentFrame()

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

◆ 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: