TwoFrameLinker is a utility class to extend a Component such that it connects two Frames. More...

Inheritance diagram for OpenSim::TwoFrameLinker< C, F >:

OpenSim Properties, Sockets, Outputs, Inputs
Properties (list)
Frames added to satisfy the sockets of this TwoFrameLinker Component
F	frames
	"Frames created/added to satisfy this component's connections." More...

Sockets
F	frame1
	"The first frame participating in this linker." More...

F	frame2
	"The second frame participating in this linker." More...

Public Member Functions
	TwoFrameLinker ()
	By default, the TwoFrameLinker is not connected to any frames. More...

	TwoFrameLinker (const std::string &name, const F &frame1, const F &frame2)
	Convenience Constructor. More...

	TwoFrameLinker (const std::string &name, const std::string &frame1Name, const std::string &frame2Name)
	Convenience Constructor. More...

	TwoFrameLinker (const std::string &name, const F &frame1, const SimTK::Transform &offsetOnFrame1, const F &frame2, const SimTK::Transform &offsetOnFrame2)
	Convenience Constructor with two Frames Construct a TwoFrameLinker where the two frames are specified by name and offset transforms on the respective frames. More...

	TwoFrameLinker (const std::string &name, const std::string &frame1Name, const SimTK::Transform &offsetOnFrame1, const std::string &frame2Name, const SimTK::Transform &offsetOnFrame2)
	Convenience Constructor Construct a TwoFrameLinker where the two frames are specified by name and offset transforms on the respective frames. More...

	TwoFrameLinker (const std::string &name, const PhysicalFrame &frame1, const SimTK::Vec3 &locationInFrame1, const SimTK::Vec3 &orientationInFrame1, const PhysicalFrame &frame2, const SimTK::Vec3 &locationInFrame2, const SimTK::Vec3 &orientationInFrame2)
	Backwards compatible Convenience Constructor TwoFrameLinker with offsets specified in terms of the location and orientation in respective PhysicalFrames. More...

	TwoFrameLinker (const std::string &name, const std::string &frame1Name, const SimTK::Vec3 &locationInFrame1, const SimTK::Vec3 &orientationInFrame1, const std::string &frame2Name, const SimTK::Vec3 &locationInFrame2, const SimTK::Vec3 &orientationInFrame2)
	Backwards compatible Convenience Constructor TwoFrameLinker with offsets specified in terms of the location and orientation in respective PhysicalFrames. More...

const F &	getFrame1 () const
	Access the first frame the TwoFrameLinker component connects. More...

const F &	getFrame2 () const
	Access the second frame the TwoFrameLinker component connects. More...

SimTK::Transform	computeRelativeOffset (const SimTK::State &s) const
	Compute the relative offset Transform between the two frames linked by this TwoFrameLinker component at a given State, expressed in frame1. More...

SimTK::SpatialVec	computeRelativeVelocity (const SimTK::State &s) const
	Compute the relative spatial velocity between the two frames linked by this TwoFrameLinker component at a given State, expressed in frame1. More...

SimTK::Vec6	computeDeflection (const SimTK::State &s) const
	Compute the deflection (spatial separation) of the two frames connected by the TwoFrameLinker. More...

SimTK::Vec6	computeDeflectionRate (const SimTK::State &s) const
	Compute the deflection rate (dqdot) of the two frames connected by this TwoFrameLinker component. More...

Property-related functions
const F &	get_frames (int i) const
	Get the value of the i-th element of the frames property. More...

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

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

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

Socket-related functions
void	connectSocket_frame1 (const Object &object)
	Connect the 'frame1' Socket to an object of type F. More...

void	connectSocket_frame2 (const Object &object)
	Connect the 'frame2' Socket to an object of type F. More...

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

static const std::string &	getClassName ()
	This returns "TwoFrameLinker_<T>_". More...

TwoFrameLinker *	clone () const override=0

const std::string &	getConcreteClassName () const override=0

Detailed Description

template<class C = Component, class F = Frame>
class OpenSim::TwoFrameLinker< C, F >

TwoFrameLinker is a utility class to extend a Component such that it connects two Frames.

For example, a WeldConstraint and BushingForces operate between two frames to restrict their motion. A TwoFrameLinker<Force, PhysicalFrame>, for example, is a Force that operates between two PhyscialFrames and it is the base class for BushingForces. (A class whose super class is a template parameter is called a mixin class.)

class BushingForce : public TwoFrameLinker<Force, PhysicalFrame>

Template Parameters

C	The base class.
F	The type of frame that the class links together.

Author: Ajay Seth

Constructor & Destructor Documentation

◆ TwoFrameLinker() [1/7]

template<class C , class F >

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker ( )

By default, the TwoFrameLinker is not connected to any frames.

◆ TwoFrameLinker() [2/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const F &	frame1,
		const F &	frame2
	)

Convenience Constructor.

Create a TwoFrameLinker Component between two Frames.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1	the name of the first Frame being linked
[in]	frame2	the name of the second Frame being linked

◆ TwoFrameLinker() [3/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const std::string &	frame1Name,
		const std::string &	frame2Name
	)

Convenience Constructor.

Create a TwoFrameLinker Component between two Frames identified by name.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1Name	the name of the first Frame being linked
[in]	frame2Name	the name of the second Frame being linked

◆ TwoFrameLinker() [4/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const F &	frame1,
		const SimTK::Transform &	offsetOnFrame1,
		const F &	frame2,
		const SimTK::Transform &	offsetOnFrame2
	)

Convenience Constructor with two Frames Construct a TwoFrameLinker where the two frames are specified by name and offset transforms on the respective frames.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1	the first Frame being linked
[in]	offsetOnFrame1	offset Transform on the first frame
[in]	frame2	the second Frame being linked
[in]	offsetOnFrame2	offset Transform on the second frame

◆ TwoFrameLinker() [5/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const std::string &	frame1Name,
		const SimTK::Transform &	offsetOnFrame1,
		const std::string &	frame2Name,
		const SimTK::Transform &	offsetOnFrame2
	)

Convenience Constructor Construct a TwoFrameLinker where the two frames are specified by name and offset transforms on the respective frames.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1Name	the name of the first Frame being linked
[in]	offsetOnFrame1	offset Transform on the first frame
[in]	frame2Name	the name of the second Frame being linked
[in]	offsetOnFrame2	offset Transform on the second frame

◆ TwoFrameLinker() [6/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const PhysicalFrame &	frame1,
		const SimTK::Vec3 &	locationInFrame1,
		const SimTK::Vec3 &	orientationInFrame1,
		const PhysicalFrame &	frame2,
		const SimTK::Vec3 &	locationInFrame2,
		const SimTK::Vec3 &	orientationInFrame2
	)

Backwards compatible Convenience Constructor TwoFrameLinker with offsets specified in terms of the location and orientation in respective PhysicalFrames.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1	the first Frame being linked
[in]	locationInFrame1	Vec3 of offset location on the first frame
[in]	orientationInFrame1	Vec3 of orientation offset expressed as XYZ body-fixed Euler angles w.r.t frame1.
[in]	frame2	the second Frame being linked
[in]	locationInFrame2	Vec3 of offset location on the second frame
[in]	orientationInFrame2	Vec3 of orientation offset expressed as XYZ body-fixed Euler angles w.r.t frame2.

◆ TwoFrameLinker() [7/7]

template<class C , class F>

OpenSim::TwoFrameLinker< C, F >::TwoFrameLinker	(	const std::string &	name,
		const std::string &	frame1Name,
		const SimTK::Vec3 &	locationInFrame1,
		const SimTK::Vec3 &	orientationInFrame1,
		const std::string &	frame2Name,
		const SimTK::Vec3 &	locationInFrame2,
		const SimTK::Vec3 &	orientationInFrame2
	)

Backwards compatible Convenience Constructor TwoFrameLinker with offsets specified in terms of the location and orientation in respective PhysicalFrames.

Parameters

[in]	name	the name of this TwoFrameLinker component
[in]	frame1Name	the name of the first Frame being linked
[in]	locationInFrame1	Vec3 of offset location on the first frame
[in]	orientationInFrame1	Vec3 of orientation offset expressed as XYZ body-fixed Euler angles w.r.t frame1.
[in]	frame2Name	the name of the second Frame being linked
[in]	locationInFrame2	Vec3 of offset location on the second frame
[in]	orientationInFrame2	Vec3 of orientation offset expressed as XYZ body-fixed Euler angles w.r.t frame2.

Member Function Documentation

◆ addInPhysicalForcesFromInternal()

template<class C , class F >

void OpenSim::TwoFrameLinker< C, F >::addInPhysicalForcesFromInternal	(	const SimTK::State &	state,
		SimTK::Vec6	f,
		SimTK::Vector_< SimTK::SpatialVec > &	spatialForces
	)		const

protected

Helper method to add in the equivalent system spatial forces given internal forces.

Internal forces are expressed in the mobility basis as parameterized by the deflection between frame1 and frame2, dq, and its time derivative, dqdot. The intended usage is within a Force::computeForce() which is tasked with populating vectors of generalized forces and/or (mobilized body) spatial forces. This method will populate (add in) the spatialForces given the internal force.

Parameters

	state	const State of current system configuration
[in]	f	Vec6 of forces in the basis of the deflection
[in,out]	spatialForces	Vector of SpatialVec's (torque, force) on each PhysicalFrame's base frame in the System. This is equivalent to each MobilizedBody.

See also: convertInternalForceToForcesOnFrames(); PhysicalFrame::findBaseFrame()

◆ append_frames()

template<class C = Component, class F = Frame>

int OpenSim::TwoFrameLinker< C, F >::append_frames ( const F & value )

inline

Append an element to the frames property.

◆ clone()

template<class C = Component, class F = Frame>

TwoFrameLinker* OpenSim::TwoFrameLinker< C, F >::clone ( ) const

overridepure virtual

Implemented in OpenSim::ExpressionBasedBushingForce, OpenSim::FunctionBasedBushingForce, OpenSim::BushingForce, and OpenSim::WeldConstraint.

◆ computeDeflection()

template<class C , class F >

SimTK::Vec6 OpenSim::TwoFrameLinker< C, F >::computeDeflection ( const SimTK::State & s ) const

Compute the deflection (spatial separation) of the two frames connected by the TwoFrameLinker.

Angular deflections expressed as XYZ body-fixed Euler angles of frame2 w.r.t frame1. NOTE: When using deflections to compute spatial forces, these forces may not be valid for large deflections, because Euler angles are unable to uniquely distinguish an X rotation angle of +/-180 degs, and subsequent rotations that are +/-90 degs. It is mainly useful for calculating errors for constraints and forces for computing restoration forces.

Returns: dq Vec6 of (3) angular and (3) translational deflections.

◆ computeDeflectionRate()

template<class C , class F >

SimTK::Vec6 OpenSim::TwoFrameLinker< C, F >::computeDeflectionRate ( const SimTK::State & s ) const

Compute the deflection rate (dqdot) of the two frames connected by this TwoFrameLinker component.

Angular velocity is expressed as Euler (XYZ body-fixed) angle derivatives. Note that the derivatives become singular as the second Euler angle approaches 90 degs.

Returns: dqdot Vec6 of (3) angular and (3) translational deflection rates.

◆ computeRelativeOffset()

template<class C , class F >

SimTK::Transform OpenSim::TwoFrameLinker< C, F >::computeRelativeOffset ( const SimTK::State & s ) const

Compute the relative offset Transform between the two frames linked by this TwoFrameLinker component at a given State, expressed in frame1.

◆ computeRelativeVelocity()

template<class C , class F >

SimTK::SpatialVec OpenSim::TwoFrameLinker< C, F >::computeRelativeVelocity ( const SimTK::State & s ) const

Compute the relative spatial velocity between the two frames linked by this TwoFrameLinker component at a given State, expressed in frame1.

◆ connectSocket_frame1()

template<class C = Component, class F = Frame>

void OpenSim::TwoFrameLinker< C, F >::connectSocket_frame1 ( const Object & object )

inline

Connect the 'frame1' Socket to an object of type F.

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_frame2()

template<class C = Component, class F = Frame>

void OpenSim::TwoFrameLinker< C, F >::connectSocket_frame2 ( const Object & object )

inline

Connect the 'frame2' Socket to an object of type F.

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.

◆ convertInternalForceToForcesOnFrames()

template<class C , class F >

void OpenSim::TwoFrameLinker< C, F >::convertInternalForceToForcesOnFrames	(	const SimTK::State &	state,
		SimTK::Vec6	f,
		SimTK::SpatialVec &	F1_G,
		SimTK::SpatialVec &	F2_G
	)		const

protected

Helper method to convert internal force expressed in the mobility basis between frame1 and frame2, dq, as individual spatial forces acting on each frame linked by this component.

The internal force, f, is directed onto frame2 from frame1. In computeDeflection(), frame2's pose in frame1 is decomposed in to 6 internal coordinates dq (similar to the q's of a free joint). Their derivatives, dqdot, form a internal coordinates "mobility" basis that can be used to express frame2's spatial velocity in frame1 or to apply internal (generalized) forces that apply equal and opposite spatial forces to the two frames.

Parameters

	state	const State of current system configuration
[in]	f	Vec6 of forces in the basis of the deflection
[in,out]	F1_G	SpatialVec Force (torque, force) applied to frame1 expressed in ground.
[in,out]	F2_G	SpatialVec Force (torque, force) applied to frame2 expressed in ground.

◆ extendConnectToModel()

template<class C , class F >

void OpenSim::TwoFrameLinker< C, F >::extendConnectToModel ( Model & model )

overrideprotected

◆ get_frames()

template<class C = Component, class F = Frame>

const F& OpenSim::TwoFrameLinker< C, F >::get_frames ( int i ) const

inline

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

◆ getClassName()

template<class C = Component, class F = Frame>

static const std::string& OpenSim::TwoFrameLinker< C, F >::getClassName ( )

inlinestatic

This returns "TwoFrameLinker_<T>_".

T is the template argument for this class. See getConcreteClassName() if you want the class name of the underlying concrete object instead.

◆ getConcreteClassName()

template<class C = Component, class F = Frame>

const std::string& OpenSim::TwoFrameLinker< C, F >::getConcreteClassName ( ) const

overridepure virtual

Implemented in OpenSim::ExpressionBasedBushingForce, OpenSim::FunctionBasedBushingForce, OpenSim::BushingForce, and OpenSim::WeldConstraint.

◆ getFrame1()

template<class C , class F >

const F & OpenSim::TwoFrameLinker< C, F >::getFrame1 ( ) const

Access the first frame the TwoFrameLinker component connects.

Note, if an offset was introduced at construction, then this will be the offset frame.

◆ getFrame2()

template<class C , class F >

const F & OpenSim::TwoFrameLinker< C, F >::getFrame2 ( ) const

Access the second frame the TwoFrameLinker component connects.

Note, if an offset was introduced at construction, then this will be the offset frame.

◆ safeDownCast()

template<class C = Component, class F = Frame>

static TwoFrameLinker* OpenSim::TwoFrameLinker< C, F >::safeDownCast ( OpenSim::Object * obj )

inlinestatic

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

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

◆ set_frames()

template<class C = Component, class F = Frame>

void OpenSim::TwoFrameLinker< C, F >::set_frames	(	int	i,
		const F &	value
	)

inline

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

◆ upd_frames()

template<class C = Component, class F = Frame>

F& OpenSim::TwoFrameLinker< C, F >::upd_frames ( int i )

inline

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

◆ updateFromXMLNode()

template<class C , class F >

void OpenSim::TwoFrameLinker< C, F >::updateFromXMLNode	(	SimTK::Xml::Element &	aNode,
		int	versionNumber
	)

overrideprotected

OpenSim Property, Socket, Output, Input Documentation

◆ frame1

template<class C = Component, class F = Frame>

F OpenSim::TwoFrameLinker< C, F >::frame1

"The first frame participating in this linker."

In an XML file, you can set this Socket's connectee path via the <socket_frame1 > element. This socket was generated with the OpenSim_DECLARE_SOCKET macro; see AbstractSocket for more information.

See also: connectSocket_frame1()

◆ frame2

template<class C = Component, class F = Frame>

F OpenSim::TwoFrameLinker< C, F >::frame2

"The second frame participating in this linker."

In an XML file, you can set this Socket's connectee path via the <socket_frame2 > element. This socket was generated with the OpenSim_DECLARE_SOCKET macro; see AbstractSocket for more information.

See also: connectSocket_frame2()

◆ frames

template<class C = Component, class F = Frame>

F OpenSim::TwoFrameLinker< C, F >::frames

"Frames created/added to satisfy this component's connections."

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()

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

OpenSim/Simulation/Model/TwoFrameLinker.h

OpenSim Properties, Sockets, Outputs, Inputs

Public Member Functions

Auto-generated functions

Detailed Description

template<class C = Component, class F = Frame> class OpenSim::TwoFrameLinker< C, F >

Constructor & Destructor Documentation

◆ TwoFrameLinker() [1/7]

◆ TwoFrameLinker() [2/7]

◆ TwoFrameLinker() [3/7]

◆ TwoFrameLinker() [4/7]

◆ TwoFrameLinker() [5/7]

◆ TwoFrameLinker() [6/7]

◆ TwoFrameLinker() [7/7]

Member Function Documentation

◆ addInPhysicalForcesFromInternal()

◆ append_frames()

◆ clone()

◆ computeDeflection()

◆ computeDeflectionRate()

◆ computeRelativeOffset()

◆ computeRelativeVelocity()

◆ connectSocket_frame1()

◆ connectSocket_frame2()

◆ convertInternalForceToForcesOnFrames()

◆ extendConnectToModel()

◆ get_frames()

◆ getClassName()

◆ getConcreteClassName()

◆ getFrame1()

◆ getFrame2()

◆ safeDownCast()

◆ set_frames()

◆ upd_frames()

◆ updateFromXMLNode()

OpenSim Property, Socket, Output, Input Documentation

◆ frame1

◆ frame2

◆ frames

template<class C = Component, class F = Frame>
class OpenSim::TwoFrameLinker< C, F >