Simbody
3.7
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Arbitrary discrete body forces and mobility (generalized) forces. Useful for applying external forces or forces that are updated at discrete times due to the occurrence of events. More...
Public Member Functions | |
DiscreteForces (GeneralForceSubsystem &forces, const SimbodyMatterSubsystem &matter) | |
Create a DiscreteForces force element. More... | |
DiscreteForces () | |
Default constructor creates an empty handle. More... | |
void | clearAllForces (State &state) const |
Set to zero all forces stored by this force element in the given state, including both generalized forces and body spatial forces. More... | |
void | clearAllMobilityForces (State &state) const |
Set to zero all generalized forces stored by this force element in the given state. More... | |
void | clearAllBodyForces (State &state) const |
Set to zero all body spatial forces (force and torques) stored by this force element in the given state. More... | |
void | setOneMobilityForce (State &state, const MobilizedBody &mobod, MobilizerUIndex whichU, Real force) const |
Change the value of a generalized force to be applied in the given state. More... | |
void | setOneBodyForce (State &state, const MobilizedBody &mobod, const SpatialVec &spatialForceInG) const |
Change the value of the discrete spatial force (force and torque) to be applied to a body in the given state. More... | |
void | addForceToBodyPoint (State &state, const MobilizedBody &mobod, const Vec3 &pointInB, const Vec3 &forceInG) const |
Convenience method to add in a force applied at a point (station) on a particular body into the forces currently set to be applied to that body in this state. More... | |
void | setAllMobilityForces (State &state, const Vector &f) const |
Set all the generalized forces at once. More... | |
void | setAllBodyForces (State &state, const Vector_< SpatialVec > &bodyForcesInG) const |
Set all the body spatial forces at once. More... | |
Real | getOneMobilityForce (const State &state, const MobilizedBody &mobod, MobilizerUIndex whichU) const |
Return the value for a generalized force that is stored in the given state. More... | |
SpatialVec | getOneBodyForce (const State &state, const MobilizedBody &mobod) const |
Return the value for the discrete spatial force (force and torque) on a particular body that is stored in the given state. More... | |
const Vector & | getAllMobilityForces (const State &state) const |
Get a reference to the internal Vector of all the generalized forces currently set to be applied by this force element. More... | |
const Vector_< SpatialVec > & | getAllBodyForces (const State &state) const |
Get a reference to the internal Vector of all the body spatial forces currently set to be applied by this force element. 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 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... | |
Arbitrary discrete body forces and mobility (generalized) forces. Useful for applying external forces or forces that are updated at discrete times due to the occurrence of events.
SimTK::Force::DiscreteForces::DiscreteForces | ( | GeneralForceSubsystem & | forces, |
const SimbodyMatterSubsystem & | matter | ||
) |
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inline |
Default constructor creates an empty handle.
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inline |
Set to zero all forces stored by this force element in the given state, including both generalized forces and body spatial forces.
void SimTK::Force::DiscreteForces::clearAllMobilityForces | ( | State & | state | ) | const |
Set to zero all generalized forces stored by this force element in the given state.
void SimTK::Force::DiscreteForces::clearAllBodyForces | ( | State & | state | ) | const |
Set to zero all body spatial forces (force and torques) stored by this force element in the given state.
void SimTK::Force::DiscreteForces::setOneMobilityForce | ( | State & | state, |
const MobilizedBody & | mobod, | ||
MobilizerUIndex | whichU, | ||
Real | force | ||
) | const |
Change the value of a generalized force to be applied in the given state.
Set this to zero if you don't want it to do anything. You can call this method any time after realizeTopology() since the force just needs to be saved in the state.
state | The state in which the generalized force is to be saved. |
mobod | The mobilizer to which the force should be applied. |
whichU | To which of the mobilizer's mobilities (degrees of freedom) should this force be applied (first is 0)? |
force | The scalar value of the generalized force. |
void SimTK::Force::DiscreteForces::setOneBodyForce | ( | State & | state, |
const MobilizedBody & | mobod, | ||
const SpatialVec & | spatialForceInG | ||
) | const |
Change the value of the discrete spatial force (force and torque) to be applied to a body in the given state.
Set this to zero if you don't want any force applied to the body. You can call this method any time after realizeTopology() since the force just needs to be saved in the state.
state | The state in which the force is to be saved. |
mobod | The mobilized body to which the force should be applied. |
spatialForceInG | The (torque,force) pair as a SpatialVec. These are expressed in the Ground frame and the force is applied to the body origin. |
void SimTK::Force::DiscreteForces::addForceToBodyPoint | ( | State & | state, |
const MobilizedBody & | mobod, | ||
const Vec3 & | pointInB, | ||
const Vec3 & | forceInG | ||
) | const |
Convenience method to add in a force applied at a point (station) on a particular body into the forces currently set to be applied to that body in this state.
The station location is given in the body frame and the force is given in the Ground frame. Note that the state must have been realized to Stage::Position because we need to know the body orientation in order to shift the applied force to the body origin.
Be sure to call setOneBodyForce() to initialize this force to zero before you start accumulating point forces using this method.
state | The state in which the force is saved. Must already have been realized to at least Stage::Position. |
mobod | The mobilized body to which the force will be applied. |
pointInB | The body station at which the force will be applied, measured and expressed in the body frame. |
forceInG | The force vector to be applied, expressed in Ground. |
Set all the generalized forces at once.
These will be applied until they are changed.
state | The state in which the generalized forces are saved. |
f | The set of n generalized forces. This Vector must be either empty (in which case it is treated as though it were all zero) or the same length as the number of generalized speeds (state.getNU()). |
void SimTK::Force::DiscreteForces::setAllBodyForces | ( | State & | state, |
const Vector_< SpatialVec > & | bodyForcesInG | ||
) | const |
Set all the body spatial forces at once.
These will be applied until they are changed.
state | The state in which the forces are saved. |
bodyForcesInG | The set of nb spatial forces (torque,force) pairs, expressed in the Ground frame, with the forces applied at each body frame origin. This Vector must be either empty (in which case it is treated as though it were all zero) or the same length as the number of mobilized bodies in the system (and don't forget that Ground is mobilized body 0). |
Real SimTK::Force::DiscreteForces::getOneMobilityForce | ( | const State & | state, |
const MobilizedBody & | mobod, | ||
MobilizerUIndex | whichU | ||
) | const |
Return the value for a generalized force that is stored in the given state.
If no calls to setGeneralizedForce() have been made on this state then zero will be returned.
SpatialVec SimTK::Force::DiscreteForces::getOneBodyForce | ( | const State & | state, |
const MobilizedBody & | mobod | ||
) | const |
Return the value for the discrete spatial force (force and torque) on a particular body that is stored in the given state.
The result is a force applied at the body origin and expressed in the Ground frame.
Get a reference to the internal Vector of all the generalized forces currently set to be applied by this force element.
This will be length zero if no forces are being applied; otherwise, its length will be the number of generalized speeds u in the given state. The returned reference is a reference into the given state object.
const Vector_<SpatialVec>& SimTK::Force::DiscreteForces::getAllBodyForces | ( | const State & | state | ) | const |
Get a reference to the internal Vector of all the body spatial forces currently set to be applied by this force element.
This will be length zero if no body forces are being applied; otherwise, its length will be the number of mobilized bodies in the containing MultibodySystem.
The returned reference is a reference into the given state object.