OpenSim::TorsionalSpring Class Reference

#include <TorsionalSpring.h>

Inheritance diagram for OpenSim::TorsionalSpring:

List of all members.

Public Member Functions
	TorsionalSpring (const Body &aBody, double startTime, double endTime)
	Construct a derivative callback instance for applying external torques during an integration.
virtual	~TorsionalSpring ()
	Destructor.
void	setTargetPosition (VectorFunction *aPosFunction)
	Set the vetor function containing the nominal angular postion of the body.
VectorFunction *	getTargetPosition () const
	Get the vector function containing the nominal angular position of the body.
void	setTargetVelocity (VectorFunction *aVelFunction)
	Set the vector function containing the nominal angular velocity of the body.
VectorFunction *	getTargetVelocity () const
	Get the vector function containing the nominal angular velocity of the body.
void	setScaleFunction (Function *_scaleFunction)
	Set the function containing the scale factor as a function of time.
Function *	getScaleFunction () const
	Get the function containing the scale factor as a function of time.
void	setScaleFactor (double aScaleFactor)
	Set the scale factor that pre-multiplies the applied torque.
double	getScaleFactor ()
	Get the scale factor that pre-multiplies the applied torque.
void	setKValue (const SimTK::Vec3 &aK)
	Set the spring constant, k.
void	getKValue (SimTK::Vec3 &aK)
	Get the spring constant, k.
void	setBValue (const SimTK::Vec3 &aB)
	Set the damping constant, b.
void	getBValue (SimTK::Vec3 &aB)
	Get the damping constant, b.
void	setThreshold (double aThreshold)
	Set the magnitude theshold below which no torque is applied.
double	getThreshold () const
	Get the magnitude theshold below which no torque is applied.
void	computeTargetFunctions (SimTK::State &s, const Storage &aQStore, const Storage &aUStore)
	Compute the target orientation and angular velocity of the body.
virtual void	computeForce (const SimTK::State &s) const
	Implement the Force.
Protected Attributes
VectorFunction *	_targetPosition
	Vector function containing target orientation of the body.
VectorFunction *	_targetVelocity
	Vector function containing target angular velocity of the body.
Function *	_scaleFunction
	Function containing values for the time-dependent torque scaling factor.
double	_scaleFactor
	Scale factor that pre-multiplies the applied torque.
SimTK::Vec3	_k
	Stiffness.
SimTK::Vec3	_b
	Damping.
double	_threshold
	If the magnitude of the torque is below this threshold, no torque is applied.
const Body &	_body
bool	_on
	On, off flag.
double	_startTime
	Start time for the force.
double	_endTime
	End time for the force.

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Constructor & Destructor Documentation

TorsionalSpring::TorsionalSpring	(	const Body &	aBody,
		double	startTime,
		double	endTime
	)

Construct a derivative callback instance for applying external torques during an integration.

Parameters:

	aModel	Model for which external torques are to be applied.
	aBody	Body to which external torques are to be applied.

TorsionalSpring::~TorsionalSpring

(

)

[virtual]

Destructor.

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Member Function Documentation

void TorsionalSpring::computeForce

(

const SimTK::State &

s

)

const [virtual]

Implement the Force.

Parameters:

s

States.

Implements OpenSim::CustomForce.

void TorsionalSpring::computeTargetFunctions	(	SimTK::State &	s,
		const Storage &	aQStore,
		const Storage &	aUStore
	)

Compute the target orientation and angular velocity of the body.

A spring force is applied based on the difference between the body's actual orientation and angular velocities and corresponding target values. The target orientation and angular velocity are computed with respect to the global frame.

Parameters:

	aQStore	Storage containing the time history of generalized coordinates for the model. Note that all generalized coordinates must be specified and in radians and Euler parameters.
	aUStore	Stoarge containing the time history of generalized speeds for the model. Note that all generalized speeds must be specified and in radians.

void TorsionalSpring::getBValue

(

SimTK::Vec3 &

aB

)

Get the damping constant, b.

Returns:

aB.

void TorsionalSpring::getKValue

(

SimTK::Vec3 &

aK

)

Get the spring constant, k.

Returns:

aK.

double TorsionalSpring::getScaleFactor

(

)

Get the scale factor that pre-multiplies the applied torque.

Returns:

aScaleFactor.

Function * TorsionalSpring::getScaleFunction

(

)

const

Get the function containing the scale factor as a function of time.

Returns:

aScaleFunction.

VectorFunction * TorsionalSpring::getTargetPosition

(

)

const

Get the vector function containing the nominal angular position of the body.

Returns:

aPosFunction.

VectorFunction * TorsionalSpring::getTargetVelocity

(

)

const

Get the vector function containing the nominal angular velocity of the body.

Returns:

aVelFunction.

double TorsionalSpring::getThreshold

(

)

const

Get the magnitude theshold below which no torque is applied.

Parameters:

aThreshold

Magnitude threshold. A negative value or 0 will result in the torque always being applied.

void TorsionalSpring::setBValue

(

const SimTK::Vec3 &

aB

)

Set the damping constant, b.

Parameters:

aK

Vector of three values of b.

void TorsionalSpring::setKValue

(

const SimTK::Vec3 &

aK

)

Set the spring constant, k.

Parameters:

aK

Vector of three values of k.

void TorsionalSpring::setScaleFactor

(

double

aScaleFactor

)

Set the scale factor that pre-multiplies the applied torque.

Parameters:

aScaleFactor

void TorsionalSpring::setScaleFunction

(

Function *

aScaleFunction

)

Set the function containing the scale factor as a function of time.

Parameters:

aScaleFunction.

void TorsionalSpring::setTargetPosition

(

VectorFunction *

aPosFunction

)

Set the vetor function containing the nominal angular postion of the body.

Parameters:

aPosFunction

Vector function containing the nominal angular position of the body in the intertial reference frame.

void TorsionalSpring::setTargetVelocity

(

VectorFunction *

aVelFunction

)

Set the vector function containing the nominal angular velocity of the body.

Parameters:

aPosFunction

Vector function containing the nominal angular velocity of the body in the intertial reference frame.

void TorsionalSpring::setThreshold

(

double

aThreshold

)

Set the magnitude theshold below which no torque is applied.

Parameters:

aThreshold

Magnitude threshold. A negative value or 0 will result in the torque always being applied.

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Member Data Documentation

SimTK::Vec3 OpenSim::TorsionalSpring::_b [protected]

Damping.

const Body& OpenSim::TorsionalSpring::_body [protected]

double OpenSim::TorsionalSpring::_endTime [protected]

End time for the force.

SimTK::Vec3 OpenSim::TorsionalSpring::_k [protected]

Stiffness.

bool OpenSim::TorsionalSpring::_on [protected]

On, off flag.

double OpenSim::TorsionalSpring::_scaleFactor [protected]

Scale factor that pre-multiplies the applied torque.

Function* OpenSim::TorsionalSpring::_scaleFunction [protected]

Function containing values for the time-dependent torque scaling factor.

double OpenSim::TorsionalSpring::_startTime [protected]

Start time for the force.

VectorFunction* OpenSim::TorsionalSpring::_targetPosition [protected]

Vector function containing target orientation of the body.

VectorFunction* OpenSim::TorsionalSpring::_targetVelocity [protected]

Vector function containing target angular velocity of the body.

double OpenSim::TorsionalSpring::_threshold [protected]

If the magnitude of the torque is below this threshold, no torque is applied.

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

• OpenSim/Simulation/Model/TorsionalSpring.h
• OpenSim/Simulation/Model/TorsionalSpring.cpp