Simbody
3.6

Constrain a single mobilizer coordinate q to have a particular value. More...
Public Member Functions  
ConstantCoordinate (MobilizedBody &mobilizer, MobilizerQIndex whichQ, Real defaultPosition)  
Construct a constant coordinate constraint on a particular generalized coordinate q of the given mobilizer. More...  
ConstantCoordinate (MobilizedBody &mobilizer, Real defaultPosition)  
Construct a constant coordinate constraint on the generalized coordinate q of the given mobilizer, assuming there is only one coordinate. More...  
ConstantCoordinate ()  
Default constructor creates an empty handle you can use to reference any existing ConstantCoordinate Constraint. More...  
MobilizedBodyIndex  getMobilizedBodyIndex () const 
Return the index of the mobilized body to which this constant coordinate constraint is being applied (to one of its coordinates). More...  
MobilizerQIndex  getWhichQ () const 
Return the particular coordinate whose position is controlled by this ConstantCoordinate constraint. More...  
Real  getDefaultPosition () const 
Return the default value for the position to be enforced. More...  
ConstantCoordinate &  setDefaultPosition (Real position) 
Change the default value for the position to be enforced by this constraint. More...  
void  setPosition (State &state, Real position) const 
Override the default position with this one whose value is stored in the given State. More...  
Real  getPosition (const State &state) const 
Get the current value of the position set point from the indicated State. More...  
Real  getPositionError (const State &state) const 
Return the amount by which the given State fails to satisfy this ConstantCoordinate constraint. More...  
Real  getVelocityError (const State &state) const 
Return the amount by which the given State fails to satisfy the time derivative of this ConstantCoordinate constraint, which should be zero. More...  
Real  getAccelerationError (const State &state) const 
Return the amount by which the accelerations in the given State fail to satify the second time derivative of this constraint, which should be zero. More...  
Real  getMultiplier (const State &state) const 
Get the value of the Lagrange multiplier generated to satisfy this constraint. More...  
Public Member Functions inherited from SimTK::Constraint  
Constraint ()  
Default constructor creates an empty Constraint handle that can be used to reference any Constraint. More...  
Constraint (ConstraintImpl *r)  
For internal use: construct a new Constraint handle referencing a particular implementation object. More...  
void  disable (State &) const 
Disable this Constraint, effectively removing it from the system. More...  
void  enable (State &) const 
Enable this Constraint, without necessarily satisfying it. More...  
bool  isDisabled (const State &) const 
Test whether this constraint is currently disabled in the supplied State. More...  
bool  isDisabledByDefault () const 
Test whether this Constraint is disabled by default in which case it must be explicitly enabled before it will take effect. More...  
void  setDisabledByDefault (bool shouldBeDisabled) 
Normally Constraints are enabled when defined and can be disabled later. More...  
operator ConstraintIndex () const  
This is an implicit conversion from Constraint to ConstraintIndex when needed. More...  
const SimbodyMatterSubsystem &  getMatterSubsystem () const 
Get a const reference to the matter subsystem that contains this Constraint. More...  
SimbodyMatterSubsystem &  updMatterSubsystem () 
Assuming you have writable access to this Constraint, get a writable reference to the containing matter subsystem. More...  
ConstraintIndex  getConstraintIndex () const 
Get the ConstraintIndex that was assigned to this Constraint when it was added to the matter subsystem. More...  
bool  isInSubsystem () const 
Test whether this Constraint is contained within a matter subsystem. More...  
bool  isInSameSubsystem (const MobilizedBody &mobod) const 
Test whether the supplied MobilizedBody is in the same matter subsystem as this Constraint. More...  
int  getNumConstrainedBodies () const 
Return the number of unique bodies directly restricted by this constraint. More...  
const MobilizedBody &  getMobilizedBodyFromConstrainedBody (ConstrainedBodyIndex consBodyIx) const 
Return a const reference to the actual MobilizedBody corresponding to one of the Constrained Bodies included in the count returned by getNumConstrainedBodies(). More...  
const MobilizedBody &  getAncestorMobilizedBody () const 
Return a const reference to the actual MobilizedBody which is serving as the Ancestor body for the constrained bodies in this Constraint. More...  
int  getNumConstrainedMobilizers () const 
Return the number of unique mobilizers directly restricted by this Constraint. More...  
const MobilizedBody &  getMobilizedBodyFromConstrainedMobilizer (ConstrainedMobilizerIndex consMobilizerIx) const 
Return a const reference to the actual MobilizedBody corresponding to one of the Constrained Mobilizers included in the count returned by getNumConstrainedMobilizers(). More...  
const SimbodyMatterSubtree &  getSubtree () const 
Return a subtree object indicating which parts of the multibody tree are potentially affected by this Constraint. More...  
int  getNumConstrainedQ (const State &, ConstrainedMobilizerIndex) const 
Return the number of constrainable generalized coordinates q associated with a particular constrained mobilizer. More...  
int  getNumConstrainedU (const State &, ConstrainedMobilizerIndex) const 
Return the number of constrainable mobilities u associated with a particular constrained mobilizer. More...  
ConstrainedUIndex  getConstrainedUIndex (const State &, ConstrainedMobilizerIndex, MobilizerUIndex which) const 
Return the index into the constrained mobilities u array corresponding to a particular mobility of the indicated ConstrainedMobilizer. More...  
ConstrainedQIndex  getConstrainedQIndex (const State &, ConstrainedMobilizerIndex, MobilizerQIndex which) const 
Return the index into the constrained coordinates q array corresponding to a particular coordinate of the indicated ConstrainedMobilizer. More...  
int  getNumConstrainedQ (const State &) const 
Return the sum of the number of coordinates q associated with each of the constrained mobilizers. More...  
int  getNumConstrainedU (const State &) const 
Return the sum of the number of mobilities u associated with each of the constrained mobilizers. More...  
QIndex  getQIndexOfConstrainedQ (const State &state, ConstrainedQIndex consQIndex) const 
Map one of this Constraint's constrained q's to the corresponding index within the matter subsystem's whole q vector. More...  
UIndex  getUIndexOfConstrainedU (const State &state, ConstrainedUIndex consUIndex) const 
Map one of this Constraint's constrained U's (or mobilities) to the corresponding index within the matter subsystem's whole u vector. More...  
void  getNumConstraintEquationsInUse (const State &state, int &mp, int &mv, int &ma) const 
Find out how many holonomic (position), nonholonomic (velocity), and accelerationonly constraint equations are currently being generated by this Constraint. More...  
void  getIndexOfMultipliersInUse (const State &state, MultiplierIndex &px0, MultiplierIndex &vx0, MultiplierIndex &ax0) const 
Return the start of the blocks of multipliers (or acceleration errors) assigned to this Constraint. More...  
void  setMyPartInConstraintSpaceVector (const State &state, const Vector &myPart, Vector &constraintSpace) const 
Set the part of a complete constraintspace vector that belongs to this constraint. More...  
void  getMyPartFromConstraintSpaceVector (const State &state, const Vector &constraintSpace, Vector &myPart) const 
Get the part of a complete constraintspace vector that belongs to this constraint. More...  
Vector  getPositionErrorsAsVector (const State &) const 
Get a Vector containing the position errors. More...  
Vector  calcPositionErrorFromQ (const State &, const Vector &q) const 
Matrix  calcPositionConstraintMatrixP (const State &) const 
Matrix  calcPositionConstraintMatrixPt (const State &) const 
Matrix  calcPositionConstraintMatrixPNInv (const State &) const 
void  calcConstraintForcesFromMultipliers (const State &, const Vector &lambda, Vector_< SpatialVec > &bodyForcesInA, Vector &mobilityForces) const 
This operator calculates this constraint's body and mobility forces given the complete set of multipliers lambda for this Constraint. More...  
Vector  getVelocityErrorsAsVector (const State &) const 
Get a Vector containing the velocity errors. More...  
Vector  calcVelocityErrorFromU (const State &, const Vector &u) const 
Matrix  calcVelocityConstraintMatrixV (const State &) const 
Matrix  calcVelocityConstraintMatrixVt (const State &) const 
Vector  getAccelerationErrorsAsVector (const State &) const 
Get a Vector containing the acceleration errors. More...  
Vector  calcAccelerationErrorFromUDot (const State &, const Vector &udot) const 
Vector  getMultipliersAsVector (const State &) const 
Get a Vector containing the Lagrange multipliers. More...  
void  getConstraintForcesAsVectors (const State &state, Vector_< SpatialVec > &bodyForcesInG, Vector &mobilityForces) const 
Given a State realized through Acceleration stage, return the forces that were applied to the system by this Constraint, with body forces expressed in Ground. More...  
Vector_< SpatialVec >  getConstrainedBodyForcesAsVector (const State &state) const 
For convenience, returns constrained body forces as the function return. More...  
Vector  getConstrainedMobilityForcesAsVector (const State &state) const 
For convenience, returns constrained mobility forces as the function return. More...  
Real  calcPower (const State &state) const 
Calculate the power being applied by this Constraint to the system. More...  
Matrix  calcAccelerationConstraintMatrixA (const State &) const 
Matrix  calcAccelerationConstraintMatrixAt (const State &) const 
void  setIsConditional (bool isConditional) 
(Advanced) Mark this constraint as one that is only conditionally active. More...  
bool  isConditional () const 
(Advanced) Get the value of the isConditional flag. More...  
Public Member Functions inherited from SimTK::PIMPLHandle< Constraint, ConstraintImpl, 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 Constraint &other) const 
Determine whether the supplied handle is the same object as "this" PIMPLHandle. More...  
void  disown (Constraint &newOwner) 
Give up ownership of the implementation to an empty handle. More...  
PIMPLHandle &  referenceAssign (const Constraint &source) 
"Copy" assignment but with shallow (pointer) semantics. More...  
PIMPLHandle &  copyAssign (const Constraint &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 ConstraintImpl &  getImpl () const 
Get a const reference to the implementation associated with this Handle. More...  
ConstraintImpl &  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::Constraint  
typedef Rod  ConstantDistance 
Synonym for Rod constraint. More...  
typedef Ball  CoincidentPoints 
Synonym for Ball constraint. More...  
typedef Ball  Spherical 
Synonym for Ball constraint. More...  
typedef Weld  CoincidentFrames 
Public Types inherited from SimTK::PIMPLHandle< Constraint, ConstraintImpl, true >  
typedef PIMPLHandle< Constraint, ConstraintImpl, PTR >  HandleBase 
typedef HandleBase  ParentHandle 
Protected Member Functions inherited from SimTK::PIMPLHandle< Constraint, ConstraintImpl, true >  
PIMPLHandle ()  
The default constructor makes this an empty handle. More...  
PIMPLHandle (ConstraintImpl *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 nonvirtual. 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 (ConstraintImpl *p) 
Set the implementation for this empty handle. More...  
bool  hasSameImplementation (const Constraint &other) const 
Determine whether the supplied handle is a reference to the same implementation object as is referenced by "this" PIMPLHandle. More...  
Constrain a single mobilizer coordinate q to have a particular value.
Generates one positionlevel (holonomic) constraint equation. Some generalized coordinate q is required to remain at a particular position value p. This may be an angle, a length, or some other unit depending on how the mobilizer is defined.
Consider using the lock() or lockAt() feature of mobilizers (see MobilizedBody description) instead of this constraint; if applicable, locking is more efficient since it does not require adding a constraint equation to the system.
The assembly condition is the same as the runtime constraint: q must be set to position p.
SimTK::Constraint::ConstantCoordinate::ConstantCoordinate  (  MobilizedBody &  mobilizer, 
MobilizerQIndex  whichQ,  
Real  defaultPosition  
) 
Construct a constant coordinate constraint on a particular generalized coordinate q of the given mobilizer.
Provide a default position value to which the q should be locked; you can change it later via setPosition().
SimTK::Constraint::ConstantCoordinate::ConstantCoordinate  (  MobilizedBody &  mobilizer, 
Real  defaultPosition  
) 
Construct a constant coordinate constraint on the generalized coordinate q of the given mobilizer, assuming there is only one coordinate.
(Constrains the first coordinate if there are several.) Provide a default position value to which the q should be locked; you can change it later via setPosition().
Default constructor creates an empty handle you can use to reference any existing ConstantCoordinate Constraint.
MobilizedBodyIndex SimTK::Constraint::ConstantCoordinate::getMobilizedBodyIndex  (  )  const 
Return the index of the mobilized body to which this constant coordinate constraint is being applied (to one of its coordinates).
This is set on construction of the ConstantCoordinate constraint.
MobilizerQIndex SimTK::Constraint::ConstantCoordinate::getWhichQ  (  )  const 
Return the particular coordinate whose position is controlled by this ConstantCoordinate constraint.
This is set on construction.
Real SimTK::Constraint::ConstantCoordinate::getDefaultPosition  (  )  const 
Return the default value for the position to be enforced.
This is set on construction or via setDefaultPosition(). This is used to initialize the position when a default State is created, but it can be overriden by changing the value in the State using setPosition().
ConstantCoordinate& SimTK::Constraint::ConstantCoordinate::setDefaultPosition  (  Real  position  ) 
Change the default value for the position to be enforced by this constraint.
This is a topological change, meaning you'll have to call realizeTopology() on the containing System and obtain a new State before you can use it. If you just want to make a runtime change in the State, see setPosition().
Override the default position with this one whose value is stored in the given State.
This invalidates the Position stage in the state. Don't confuse this with setDefaultPosition() – the value set here overrides that one.
Get the current value of the position set point from the indicated State.
This is the value currently in effect, either from the default or from a previous call to setPosition().
Return the amount by which the given State fails to satisfy this ConstantCoordinate constraint.
This is a signed value, qp where p is the currently effective desired position as returned by getPosition() on this same state. The state must already be realized through Stage::Position.
Return the amount by which the given State fails to satisfy the time derivative of this ConstantCoordinate constraint, which should be zero.
This is a signed value equal to the current value of qdot (=d/dt q). The state must already be realized through Stage::Velocity.
Return the amount by which the accelerations in the given State fail to satify the second time derivative of this constraint, which should be zero.
This is a signed value equal to the current value of qdotdot (=d^2/dt^2 q). The state must already be realized through Stage::Acceleration.
Get the value of the Lagrange multiplier generated to satisfy this constraint.
For a ConstantCoordinate constraint, the multiplier has the same magnitude as the generalized force although by convention constraint multipliers have the opposite sign from applied forces. The state must already be realized through Stage::Acceleration.