Constrain a single mobilizer coordinate q to have a particular value. More...
Inheritance diagram for SimTK::Constraint::ConstantCoordinate:
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 acceleration-only 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 constraint-space vector that belongs to this constraint. More... | |
| void | getMyPartFromConstraintSpaceVector (const State &state, const Vector &constraintSpace, Vector &myPart) const |
| Get the part of a complete constraint-space 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 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 (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... | |
Detailed Description
Constrain a single mobilizer coordinate q to have a particular value.
Generates one position-level (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 run-time constraint: q must be set to position p.
Constructor & Destructor Documentation
◆ ConstantCoordinate() [1/3]
| 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().
◆ ConstantCoordinate() [2/3]
| 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().
◆ ConstantCoordinate() [3/3]
Default constructor creates an empty handle you can use to reference any existing ConstantCoordinate Constraint.
Member Function Documentation
◆ getMobilizedBodyIndex()
| 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.
◆ getWhichQ()
| MobilizerQIndex SimTK::Constraint::ConstantCoordinate::getWhichQ | ( | ) | const |
Return the particular coordinate whose position is controlled by this ConstantCoordinate constraint.
This is set on construction.
◆ getDefaultPosition()
| 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().
◆ setDefaultPosition()
| 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().
◆ 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.
◆ getPosition()
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().
◆ getPositionError()
Return the amount by which the given State fails to satisfy this ConstantCoordinate constraint.
This is a signed value, q-p 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.
◆ getVelocityError()
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.
◆ getAccelerationError()
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.
◆ getMultiplier()
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.
The documentation for this class was generated from the following file:
