SimTK::Force::MobilityConstantForce Class Reference

A constant generalized force f (a scalar) applied to a mobility. More...

#include <Force_MobilityConstantForce.h>

Inheritance diagram for SimTK::Force::MobilityConstantForce:

List of all members.

Public Member Functions
	MobilityConstantForce (GeneralForceSubsystem &forces, const MobilizedBody &mobod, MobilizerUIndex whichU, Real defaultForce)
	Add a MobilityConstantForce element to the indicated Subsystem.
	MobilityConstantForce (GeneralForceSubsystem &forces, const MobilizedBody &mobod, Real defaultForce)
	Alternate constructor signature for when the mobilizer has only a single generalized speed, in which case we'll use MobilizerUIndex(0).
	MobilityConstantForce ()
	Default constructor creates an empty handle.
MobilityConstantForce &	setDefaultForce (Real defaultForce)
	Provide a new value for the default generalied force to be applied by this force element.
Real	getDefaultForce () const
	Return the default value for the generalized force.
void	setForce (State &state, Real force) const
	Change the value of the generalized force that is stored in the given state; this may differ from the default value supplied at construction.
Real	getForce (const State &state) const
	Return the value for the generalized force that is stored in the given state.
Deprecated
Methods here are for backwards compatibility but have been replaced with better ones that you should use.
	MobilityConstantForce (GeneralForceSubsystem &forces, const MobilizedBody &mobod, int whichU, Real defaultForce)
	Deprecated: Alternate signature for backwards compatibilty -- for safety you should prefer using the other constructor signature that takes a MobilizerUIndex rather than a plain int.

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Detailed Description

A constant generalized force f (a scalar) applied to a mobility.

The mobility here selects a generalized speed (u), not a generalized coordinate (q), and the meaning depends on the definition of the generalized speed. If that speed is a translation then this is a force; if a rotation then this is a torque; if anything more general then this is in compatible force units. This force does not contribute to the potential energy, so adding it to a system will cause energy not to be conserved unless you account for the power injected or dissipated here.

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Constructor & Destructor Documentation

SimTK::Force::MobilityConstantForce::MobilityConstantForce	(	GeneralForceSubsystem &	forces,
		const MobilizedBody &	mobod,
		MobilizerUIndex	whichU,
		Real	defaultForce
	)

Add a MobilityConstantForce element to the indicated Subsystem.

Parameters:

forces	Subsystem to which this force should be added.
mobod	Mobilizer to which the force should be applied.
whichU	Index within mobod of the generalized speed u to which this force should be applied (first is zero).
defaultForce	Default value for the generalized force.

SimTK::Force::MobilityConstantForce::MobilityConstantForce	(	GeneralForceSubsystem &	forces,
		const MobilizedBody &	mobod,
		Real	defaultForce
	)		[inline]

Alternate constructor signature for when the mobilizer has only a single generalized speed, in which case we'll use MobilizerUIndex(0).

See the other signature for documentation.

SimTK::Force::MobilityConstantForce::MobilityConstantForce

(

)

[inline]

Default constructor creates an empty handle.

SimTK::Force::MobilityConstantForce::MobilityConstantForce	(	GeneralForceSubsystem &	forces,
		const MobilizedBody &	mobod,
		int	whichU,
		Real	defaultForce
	)		[inline]

Deprecated: Alternate signature for backwards compatibilty -- for safety you should prefer using the other constructor signature that takes a MobilizerUIndex rather than a plain int.

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Member Function Documentation

MobilityConstantForce& SimTK::Force::MobilityConstantForce::setDefaultForce

(

Real

defaultForce

)

Provide a new value for the default generalied force to be applied by this force element.

This is a topological change because it affects the value that the containing System's default state will have when realizeTopology() is called. This is for use during construction, not for during a simulation where you should be using setForce() to set the force in a State rather than in the System.

Parameters:

defaultForce

Default value for the generalized force.

Returns:

A writable reference to this modified force element.

See also:

setForce(), getDefaultForce()

Real SimTK::Force::MobilityConstantForce::getDefaultForce

(

)

const

Return the default value for the generalized force.

This is normally set at construction but may have been changed with setDefaultForce().

See also:

setDefaultForce(), getForce()

void SimTK::Force::MobilityConstantForce::setForce	(	State &	state,
		Real	force
	)		const

Change the value of the generalized force that is stored in the given state; this may differ from the default value supplied at construction.

Parameters:

state	The State in which the bounds are changed.
force	The value of the generalized force to be applied when the state is subsequently used.

Changing this force invalidates Stage::Dynamics and above in the state since it affects force generation.

See also:

getForce(), setDefaultForce()

Real SimTK::Force::MobilityConstantForce::getForce

(

const State &

state

)

const

Return the value for the generalized force that is stored in the given state.

Note that this is not the same thing as the default force that was supplied on construction or with setDefaultForce().

See also:

setForce(), getDefaultForce()

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

• Force_MobilityConstantForce.h