OpenSim::SpringGeneralizedForce Class Reference

#include <SpringGeneralizedForce.h>

Inheritance diagram for OpenSim::SpringGeneralizedForce:

Public Member Functions
	SpringGeneralizedForce (std::string aCoordinateName="")
	SpringGeneralizedForce (const SpringGeneralizedForce &aForce)
	Copy constructor.
	~SpringGeneralizedForce ()
	Destructor.
virtual Object *	copy () const
	Copy this force and return a pointer to the copy.
void	createSystem (SimTK::MultibodySystem &system) const
	setup sets the actual Coordinate reference _coord
SpringGeneralizedForce &	operator= (const SpringGeneralizedForce &aForce)
	Assignment operator.
void	setCoordinate (Coordinate *aCoordinate)
Coordinate *	getCoordinate () const
void	setStiffness (double aStiffness)
	Set the stiffness of the spring.
double	getStiffness () const
	Get the stiffness of the force.
void	setRestLength (double aRestLength)
	Set the rest length of the spring.
double	getRestLength () const
	Get the rest length of the spring.
void	setViscosity (double aViscosity)
	Set the viscosity of the spring.
double	getViscosity () const
	Get the viscosity of the spring.
virtual OpenSim::Array < std::string >	getRecordLabels () const
	Methods to query a Force for the value actually applied during simulation The names of the quantities (column labels) is returned by this first function getRecordLabels().
virtual OpenSim::Array< double >	getRecordValues (const SimTK::State &state) const
	Given SimTK::State object extract all the values necessary to report forces, application location frame, etc.
Protected Member Functions
virtual void	computeForce (const SimTK::State &state, SimTK::Vector_< SimTK::SpatialVec > &bodyForces, SimTK::Vector &mobilityForces) const
	Compute all quantities necessary for applying the spring force to the model.
virtual void	setup (Model &aModel)
	setup sets the _model pointer to proper value _coordinate is actually set inside _createSystem
	OPENSIM_DECLARE_DERIVED (SpringGeneralizedForce, Force)
Protected Attributes
PropertyStr	_propCoordinateName
	Name of coordinate to which the spring gen force is applied.
PropertyDbl	_propStiffness
	Stiffness.
PropertyDbl	_propRestLength
	Rest length.
PropertyDbl	_propViscosity
	Viscosity.
std::string &	_coordName
double &	_stiffness
double &	_restLength
double &	_viscosity
Coordinate *	_coord
	Corresponding generalized coordinate to which the coordinate actuator is applied.

Constructor & Destructor Documentation

OpenSim::SpringGeneralizedForce::SpringGeneralizedForce ( std::string aCoordinateName = "" )

SpringGeneralizedForce::SpringGeneralizedForce ( const SpringGeneralizedForce & aForce )

Copy constructor.

Parameters:

aforce

force to be copied.

SpringGeneralizedForce::~SpringGeneralizedForce ( )

Destructor.

Member Function Documentation

void SpringGeneralizedForce::computeForce	(	const SimTK::State &	s,
		SimTK::Vector_< SimTK::SpatialVec > &	bodyForces,
		SimTK::Vector &	generalizedForces
	)			const `[protected, virtual]`

Compute all quantities necessary for applying the spring force to the model.

Force applied = -stiffness * (_coordinateValue - restLength) - viscosity * _coordinateSpeed

Reimplemented from OpenSim::Force.

Object * SpringGeneralizedForce::copy ( ) const [virtual]

Copy this force and return a pointer to the copy.

The copy constructor for this class is used.

Returns:: Pointer to a copy of this force.

Implements OpenSim::Force.

void SpringGeneralizedForce::createSystem ( SimTK::MultibodySystem & system ) const [virtual]

setup sets the actual Coordinate reference _coord

Reimplemented from OpenSim::Force.

Coordinate* OpenSim::SpringGeneralizedForce::getCoordinate ( ) const

OpenSim::Array< std::string > SpringGeneralizedForce::getRecordLabels ( ) const [virtual]

Methods to query a Force for the value actually applied during simulation The names of the quantities (column labels) is returned by this first function getRecordLabels().

Reimplemented from OpenSim::Force.

OpenSim::Array< double > SpringGeneralizedForce::getRecordValues ( const SimTK::State & state ) const [virtual]

Given SimTK::State object extract all the values necessary to report forces, application location frame, etc.

used in conjunction with getRecordLabels and should return same size Array

Reimplemented from OpenSim::Force.

double SpringGeneralizedForce::getRestLength ( ) const

Get the rest length of the spring.

Returns:: Rest length of the spring.

double SpringGeneralizedForce::getStiffness ( ) const

Get the stiffness of the force.

Returns:: Stiffness of the force.

double SpringGeneralizedForce::getViscosity ( ) const

Get the viscosity of the spring.

Returns:: Stiffness of the spring.

OpenSim::SpringGeneralizedForce::OPENSIM_DECLARE_DERIVED	(	SpringGeneralizedForce	,
		Force
	)			`[protected]`

SpringGeneralizedForce & SpringGeneralizedForce::operator= ( const SpringGeneralizedForce & aForce )

Assignment operator.

Returns:: Reference to the altered object.

Reimplemented from OpenSim::Force.

void OpenSim::SpringGeneralizedForce::setCoordinate ( Coordinate * aCoordinate )

void SpringGeneralizedForce::setRestLength ( double aRestLength )

Set the rest length of the spring.

Parameters:

aRestLength

Rest length of the spring.

void SpringGeneralizedForce::setStiffness ( double aStiffness )

Set the stiffness of the spring.

Normally the stiffness is a positive quantity. Negative stiffnessess will result in an unstable system- the force will push away from the rest length instead of pulling toward it.

Parameters:

aStiffness

Stiffness of the spring force.

void SpringGeneralizedForce::setup ( Model & aModel ) [protected, virtual]

setup sets the _model pointer to proper value _coordinate is actually set inside _createSystem

Reimplemented from OpenSim::Force.

void SpringGeneralizedForce::setViscosity ( double aViscosity )

Set the viscosity of the spring.

Normally the viscosity should be a positive number. Negative viscosities will put energy into the system rather than apply a damping force.

Parameters:

aViscosity

Viscosity of the spring.