Linear spring connecting 2 nodes with a viscous term. More...

#include <LinearSpring.h>

Inheritance diagram for SurgSim::Physics::LinearSpring:

Public Member Functions
	LinearSpring (size_t nodeId0, size_t nodeId1)
	Constructor. More...

	LinearSpring (const std::shared_ptr< Math::OdeState > state, size_t nodeId0, size_t nodeId1, double stiffness, double damping)
	Constructor. More...

	LinearSpring (const std::shared_ptr< MassSpringModel > massSpring, size_t nodeId0, size_t nodeId1, double stiffness, double damping)
	Constructor. More...

void	initialize (const SurgSim::Math::OdeState &state) override
	Initialize the Spring once everything has been set. More...

void	setStiffness (double stiffness)
	Sets the spring stiffness parameter. More...

double	getStiffness () const
	Gets the spring stiffness parameter. More...

void	setDamping (double damping)
	Sets the spring damping parameter. More...

double	getDamping () const
	Gets the spring damping parameter. More...

void	setRestLength (double restLength)
	Sets the rest length of the spring. More...

double	getRestLength () const
	Gets the rest length of the spring. More...

void	addForce (const SurgSim::Math::OdeState &state, SurgSim::Math::Vector *F, double scale=1.0) override
	Adds the spring force (computed for a given state) to a complete system force vector F (assembly) More...

void	addDamping (const SurgSim::Math::OdeState &state, SurgSim::Math::SparseMatrix *D, double scale=1.0) override
	Adds the spring damping matrix D (= -df/dv) (computed for a given state) to a complete system damping matrix D (assembly) More...

void	addStiffness (const SurgSim::Math::OdeState &state, SurgSim::Math::SparseMatrix *K, double scale=1.0) override
	Adds the spring stiffness matrix K (= -df/dx) (computed for a given state) to a complete system stiffness matrix K (assembly) More...

void	addFDK (const SurgSim::Math::OdeState &state, SurgSim::Math::Vector F, SurgSim::Math::SparseMatrix D, SurgSim::Math::SparseMatrix *K) override
	Adds the spring force vector, mass, stiffness and damping matrices (computed for a given state) into a complete system data structure F, D, K (assembly) More...

void	addMatVec (const SurgSim::Math::OdeState &state, double alphaD, double alphaK, const SurgSim::Math::Vector &vector, SurgSim::Math::Vector *F) override
	Adds the spring matrix-vector contribution F += (alphaD.D + alphaK.K).x (computed for a given state) into a complete system data structure F (assembly) More...

bool	operator== (const Spring &spring) const
	Comparison operator (equality) More...

bool	operator!= (const Spring &spring) const
	Comparison operator (inequality) More...

Public Member Functions inherited from SurgSim::Physics::Spring
virtual	~Spring ()
	Virtual destructor.

size_t	getNumNodes () const
	Gets the number of nodes the spring is connecting. More...

size_t	getNodeId (size_t springNodeId) const
	Gets the springNodeId-th node id. More...

const std::vector< size_t > &	getNodeIds () const
	Gets the node ids for this spring. More...

Protected Member Functions
bool	computeDampingAndStiffness (const SurgSim::Math::OdeState &state, SurgSim::Math::Matrix33d De, SurgSim::Math::Matrix33d Ke)
	Compute the stiffness matrix Ke = -dF1/dx1 and damping matrix De = -dF1/dv1 of this spring for a given state, where this spring is defined by its 2 nodes positions {x1, x2}, velocities {v1, v2} and forces {F1, F2=-F1}. More...

Additional Inherited Members
Protected Attributes inherited from SurgSim::Physics::Spring
std::vector< size_t >	m_nodeIds
	Node ids connected by this spring.

Detailed Description

Linear spring connecting 2 nodes with a viscous term.

Constructor & Destructor Documentation

§ LinearSpring() [1/3]

SurgSim::Physics::LinearSpring::LinearSpring	(	size_t	nodeId0,
		size_t	nodeId1
	)

Constructor.

Parameters

nodeId0,nodeId1 The node ids on which the spring is attached

§ LinearSpring() [2/3]

SurgSim::Physics::LinearSpring::LinearSpring	(	const std::shared_ptr< Math::OdeState >	state,
		size_t	nodeId0,
		size_t	nodeId1,
		double	stiffness,
		double	damping
	)

explicit

Constructor.

Parameters

state	The state to initialize the spring with (rest length calculation)
nodeId0,nodeId1	Node ids of the 2 connected masses
stiffness,damping	The spring parameters

§ LinearSpring() [3/3]

SurgSim::Physics::LinearSpring::LinearSpring	(	const std::shared_ptr< MassSpringModel >	massSpring,
		size_t	nodeId0,
		size_t	nodeId1,
		double	stiffness,
		double	damping
	)

explicit

Constructor.

Parameters

massSpring	The MassSpringModel to initialize the spring's rest length with.
nodeId0,nodeId1	Node ids of the 2 connected masses
stiffness,damping	The spring parameters

Member Function Documentation

§ addDamping()

void SurgSim::Physics::LinearSpring::addDamping	(	const SurgSim::Math::OdeState &	state,
		SurgSim::Math::SparseMatrix *	D,
		double	scale = `1.0`
	)

overridevirtual

Adds the spring damping matrix D (= -df/dv) (computed for a given state) to a complete system damping matrix D (assembly)

Parameters

	state	The state to compute the damping matrix with
[in,out]	D	The complete system damping matrix to add the spring damping matrix into
	scale	A factor to scale the added damping matrix with

Implements SurgSim::Physics::Spring.

§ addFDK()

void SurgSim::Physics::LinearSpring::addFDK	(	const SurgSim::Math::OdeState &	state,
		SurgSim::Math::Vector *	F,
		SurgSim::Math::SparseMatrix *	D,
		SurgSim::Math::SparseMatrix *	K
	)

overridevirtual

Adds the spring force vector, mass, stiffness and damping matrices (computed for a given state) into a complete system data structure F, D, K (assembly)

Parameters

	state	The state to compute everything with
[in,out]	F	The complete system force vector to add the spring force into
[in,out]	D	The complete system damping matrix to add the spring damping matrix into
[in,out]	K	The complete system stiffness matrix to add the spring stiffness matrix into

Implements SurgSim::Physics::Spring.

§ addForce()

void SurgSim::Physics::LinearSpring::addForce	(	const SurgSim::Math::OdeState &	state,
		SurgSim::Math::Vector *	F,
		double	scale = `1.0`
	)

overridevirtual

Adds the spring force (computed for a given state) to a complete system force vector F (assembly)

Parameters

	state	The state to compute the force with
[in,out]	F	The complete system force vector to add the spring force into
	scale	A factor to scale the added force with

Implements SurgSim::Physics::Spring.

§ addMatVec()

void SurgSim::Physics::LinearSpring::addMatVec	(	const SurgSim::Math::OdeState &	state,
		double	alphaD,
		double	alphaK,
		const SurgSim::Math::Vector &	vector,
		SurgSim::Math::Vector *	F
	)

overridevirtual

Adds the spring matrix-vector contribution F += (alphaD.D + alphaK.K).x (computed for a given state) into a complete system data structure F (assembly)

Parameters

	state	The state to compute everything with
	alphaD	The scaling factor for the damping contribution
	alphaK	The scaling factor for the stiffness contribution
	vector	A complete system vector to use as the vector in the matrix-vector multiplication
[in,out]	F	The complete system force vector to add the element matrix-vector contribution into

Implements SurgSim::Physics::Spring.

§ addStiffness()

void SurgSim::Physics::LinearSpring::addStiffness	(	const SurgSim::Math::OdeState &	state,
		SurgSim::Math::SparseMatrix *	K,
		double	scale = `1.0`
	)

overridevirtual

Adds the spring stiffness matrix K (= -df/dx) (computed for a given state) to a complete system stiffness matrix K (assembly)

Parameters

	state	The state to compute the stiffness matrix with
[in,out]	K	The complete system stiffness matrix to add the spring stiffness matrix into
	scale	A factor to scale the added stiffness matrix with

Implements SurgSim::Physics::Spring.

§ computeDampingAndStiffness()

bool SurgSim::Physics::LinearSpring::computeDampingAndStiffness	(	const SurgSim::Math::OdeState &	state,
		SurgSim::Math::Matrix33d *	De,
		SurgSim::Math::Matrix33d *	Ke
	)

protected

Compute the stiffness matrix Ke = -dF1/dx1 and damping matrix De = -dF1/dv1 of this spring for a given state, where this spring is defined by its 2 nodes positions {x1, x2}, velocities {v1, v2} and forces {F1, F2=-F1}.

Parameters

	state	The state to compute the jacobians from
[out]	De,Ke	Respectively the damping and stiffness matrices De and Ke

Returns: True if the matrices could be computed, False otherwise (current length is null)

Note: This method calculates only the 3x3 parts related to the force applied on the first node,; derived w.r.t. first node. By nature, we have dF2/dx2 = dF1/dx1 = -dF1/dx2 = -dF2/dx1.

§ getDamping()

double SurgSim::Physics::LinearSpring::getDamping ( ) const

Gets the spring damping parameter.

Returns: The damping assigned to the spring (in N.s.m-1)

§ getRestLength()

double SurgSim::Physics::LinearSpring::getRestLength ( ) const

Gets the rest length of the spring.

Returns: The rest length assigned to the spring (in m)

§ getStiffness()

double SurgSim::Physics::LinearSpring::getStiffness ( ) const

Gets the spring stiffness parameter.

Returns: The stiffness assigned to the spring (in N.m-1)

§ initialize()

void SurgSim::Physics::LinearSpring::initialize ( const SurgSim::Math::OdeState & state )

overridevirtual

Initialize the Spring once everything has been set.

Parameters

state The state to initialize the Spring with

Reimplemented from SurgSim::Physics::Spring.

§ operator!=()

bool SurgSim::Physics::LinearSpring::operator!= ( const Spring & spring ) const

Comparison operator (inequality)

Parameters

spring Spring to compare it to

Returns: False if the 2 springs contains the same information, true otherwise

Note: Comparison is based on spring type, rest length, stiffness and damping coefficients ONLY

§ operator==()

bool SurgSim::Physics::LinearSpring::operator== ( const Spring & spring ) const

Comparison operator (equality)

Parameters

spring Spring to compare it to

Returns: True if the 2 springs contains the same information, false otherwise

Note: Comparison is based on spring type, rest length, stiffness and damping coefficients ONLY

§ setDamping()

void SurgSim::Physics::LinearSpring::setDamping ( double damping )

Sets the spring damping parameter.

Parameters

damping The damping to assign to the spring (in N.s.m-1)

Exceptions

SurgSim::Framework::AssertionFailure damping cannot be negative

§ setRestLength()

void SurgSim::Physics::LinearSpring::setRestLength ( double restLength )

Sets the rest length of the spring.

Parameters

restLength The rest length to assign to the spring (in m)

Exceptions

SurgSim::Framework::AssertionFailure rest length cannot be negative

§ setStiffness()

void SurgSim::Physics::LinearSpring::setStiffness ( double stiffness )

Sets the spring stiffness parameter.

Parameters

stiffness The stiffness to assign to the spring (in N.m-1)

Exceptions

SurgSim::Framework::AssertionFailure stiffness cannot be negative

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

SurgSim/Physics/LinearSpring.h
SurgSim/Physics/LinearSpring.cpp

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

§ LinearSpring() [1/3]

§ LinearSpring() [2/3]

§ LinearSpring() [3/3]

Member Function Documentation

§ addDamping()

§ addFDK()

§ addForce()

§ addMatVec()

§ addStiffness()

§ computeDampingAndStiffness()

§ getDamping()

§ getRestLength()

§ getStiffness()

§ initialize()

§ operator!=()

§ operator==()

§ setDamping()

§ setRestLength()

§ setStiffness()