A linear spring between two points, specified as a station on each of two bodies. More...

Inheritance diagram for SimTK::Force::TwoPointLinearSpring:

Public Member Functions
	TwoPointLinearSpring (GeneralForceSubsystem &forces, const MobilizedBody &body1, const Vec3 &station1, const MobilizedBody &body2, const Vec3 &station2, Real k, Real x0)
	Create a TwoPointLinearSpring. More...

	TwoPointLinearSpring ()
	Default constructor creates an empty handle. More...

	SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS (TwoPointLinearSpring, TwoPointLinearSpringImpl, Force)

Public Member Functions inherited from SimTK::Force
void	disable (State &) const
	Disable this force element, effectively removing it from the System for computational purposes (it is still using its ForceIndex, however). More...

void	enable (State &) const
	Enable this force element if it was previously disabled. More...

bool	isDisabled (const State &) const
	Test whether this force element is currently disabled in the supplied State. More...

void	setDisabledByDefault (bool shouldBeDisabled)
	Normally force elements are enabled when defined and can be disabled later. More...

bool	isDisabledByDefault () const
	Test whether this force element is disabled by default in which case it must be explicitly enabled before it will take effect. More...

void	calcForceContribution (const State &state, Vector_< SpatialVec > &bodyForces, Vector_< Vec3 > &particleForces, Vector &mobilityForces) const
	Calculate the force that would be applied by this force element if the given state were realized to Dynamics stage. More...

Real	calcPotentialEnergyContribution (const State &state) const
	Calculate the potential energy contribution that is made by this force element at the given state. More...

	Force ()
	Default constructor for Force handle base class does nothing. More...

	operator ForceIndex () const
	Implicit conversion to ForceIndex when needed. More...

const GeneralForceSubsystem &	getForceSubsystem () const
	Get the GeneralForceSubsystem of which this Force is an element. More...

ForceIndex	getForceIndex () const
	Get the index of this force element within its parent force subsystem. More...

Public Member Functions inherited from SimTK::PIMPLHandle< Force, ForceImpl, true >
bool	isEmptyHandle () const
	Returns true if this handle is empty, that is, does not refer to any implementation object. More...

bool	isOwnerHandle () const
	Returns true if this handle is the owner of the implementation object to which it refers. More...

bool	isSameHandle (const Force &other) const
	Determine whether the supplied handle is the same object as "this" PIMPLHandle. More...

void	disown (Force &newOwner)
	Give up ownership of the implementation to an empty handle. More...

PIMPLHandle &	referenceAssign (const Force &source)
	"Copy" assignment but with shallow (pointer) semantics. More...

PIMPLHandle &	copyAssign (const Force &source)
	This is real copy assignment, with ordinary C++ object ("value") semantics. More...

void	clearHandle ()
	Make this an empty handle, deleting the implementation object if this handle is the owner of it. More...

const ForceImpl &	getImpl () const
	Get a const reference to the implementation associated with this Handle. More...

ForceImpl &	updImpl ()
	Get a writable reference to the implementation associated with this Handle. More...

int	getImplHandleCount () const
	Return the number of handles the implementation believes are referencing it. More...

Additional Inherited Members
Public Types inherited from SimTK::PIMPLHandle< Force, ForceImpl, true >
typedef PIMPLHandle< Force, ForceImpl, PTR >	HandleBase

typedef HandleBase	ParentHandle

Protected Member Functions inherited from SimTK::Force
	Force (ForceImpl *r)
	Use this in a derived Force handle class constructor to supply the concrete implementation object to be stored in the handle base. More...

Protected Member Functions inherited from SimTK::PIMPLHandle< Force, ForceImpl, true >
	PIMPLHandle ()
	The default constructor makes this an empty handle. More...

	PIMPLHandle (ForceImpl *p)
	This provides consruction of a handle referencing an existing implementation object. More...

	PIMPLHandle (const PIMPLHandle &source)
	The copy constructor makes either a deep (value) or shallow (reference) copy of the supplied source PIMPL object, based on whether this is a "pointer semantics" (PTR=true) or "object (value) semantics" (PTR=false, default) class. More...

	~PIMPLHandle ()
	Note that the destructor is non-virtual. More...

PIMPLHandle &	operator= (const PIMPLHandle &source)
	Copy assignment makes the current handle either a deep (value) or shallow (reference) copy of the supplied source PIMPL object, based on whether this is a "pointer sematics" (PTR=true) or "object (value) semantics" (PTR=false, default) class. More...

void	setImpl (ForceImpl *p)
	Set the implementation for this empty handle. More...

bool	hasSameImplementation (const Force &other) const
	Determine whether the supplied handle is a reference to the same implementation object as is referenced by "this" PIMPLHandle. More...

Detailed Description

A linear spring between two points, specified as a station on each of two bodies.

The stiffness k and unstretched length x0 are provided. Then if d is the unit vector from point1 to point2, and x the current separation, we have f = k(x-x0) and we apply a force f*d to point1 and -f*d to point2. This contributes to potential energy: pe = 1/2 k (x-x0)^2. It is an error if the two points become coincident, since we are unable to determine a direction for the force in that case.

Constructor & Destructor Documentation

◆ TwoPointLinearSpring() [1/2]

SimTK::Force::TwoPointLinearSpring::TwoPointLinearSpring	(	GeneralForceSubsystem &	forces,
		const MobilizedBody &	body1,
		const Vec3 &	station1,
		const MobilizedBody &	body2,
		const Vec3 &	station2,
		Real	k,
		Real	x0
	)

Create a TwoPointLinearSpring.

Parameters

forces	the subsystem to which this force should be added
body1	the first body to which the force should be applied
station1	the location on the first body at which the force should be applied
body2	the second body to which the force should be applied
station2	the location on the second body at which the force should be applied
k	the spring constant
x0	the distance at which the force is 0

◆ TwoPointLinearSpring() [2/2]

SimTK::Force::TwoPointLinearSpring::TwoPointLinearSpring ( )

inline

Default constructor creates an empty handle.

Member Function Documentation

◆ SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS()

SimTK::Force::TwoPointLinearSpring::SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS	(	TwoPointLinearSpring	,
		TwoPointLinearSpringImpl	,
		Force
	)

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

Force.h