Simbody  3.5
SimTK::Force::MobilityConstantForce Class Reference

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

+ Inheritance diagram for SimTK::Force::MobilityConstantForce:

Public Member Functions

 MobilityConstantForce (GeneralForceSubsystem &forces, const MobilizedBody &mobod, MobilizerUIndex whichU, Real defaultForce)
 Add a MobilityConstantForce element to the indicated Subsystem. More...
 
 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). More...
 
 MobilityConstantForce ()
 Default constructor creates an empty handle. More...
 
MobilityConstantForcesetDefaultForce (Real defaultForce)
 Provide a new value for the default generalied force to be applied by this force element. More...
 
Real getDefaultForce () const
 Return the default value for the generalized force. More...
 
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. More...
 
Real getForce (const State &state) const
 Return the value for the generalized force that is stored in the given state. More...
 
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. More...
 
- 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 GeneralForceSubsystemgetForceSubsystem () 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...
 
PIMPLHandlereferenceAssign (const Force &source)
 "Copy" assignment but with shallow (pointer) semantics. More...
 
PIMPLHandlecopyAssign (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...
 
PIMPLHandleoperator= (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 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.

Constructor & Destructor Documentation

Add a MobilityConstantForce element to the indicated Subsystem.

Parameters
forcesSubsystem to which this force should be added.
mobodMobilizer to which the force should be applied.
whichUIndex within mobod of the generalized speed u to which this force should be applied (first is zero).
defaultForceDefault value for the generalized force.

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.

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.

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
defaultForceDefault 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
stateThe State in which the bounds are changed.
forceThe 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()

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