SimTK::Constraint::Weld Class Reference
Six constraint equations. More...
Inheritance diagram for SimTK::Constraint::Weld:
Public Member Functions | |
| Weld (MobilizedBody &body1, MobilizedBody &body2) | |
| Make the body frame of one body coincident with the body frame of the other body. More... | |
| Weld (MobilizedBody &body1, const Transform &frame1, MobilizedBody &body2, const Transform &frame2) | |
| Make a particular frame attached to one body coincident with a particular frame attached to the other body. More... | |
| Weld () | |
| Default constructor creates an empty handle. More... | |
| Weld & | setAxisDisplayLength (Real r) |
| This is used only for visualization. More... | |
| Real | getAxisDisplayLength () const |
| Report the length being used for display of the frames being connected by this Weld. More... | |
| Weld & | setDefaultFrameOnBody1 (const Transform &) |
| Explicitly set the default value for the frame on body1 which is to be made coincident with a frame on body2. More... | |
| const Transform & | getDefaultFrameOnBody1 () const |
| Retrieve the default transform for the frame on body 1. More... | |
| Weld & | setDefaultFrameOnBody2 (const Transform &) |
| Explicitly set the default value for the frame on body2 which is to be made coincident with a frame on body1. More... | |
| const Transform & | getDefaultFrameOnBody2 () const |
| Retrieve the default transform for the frame on body 2. More... | |
| MobilizedBodyIndex | getBody1MobilizedBodyIndex () const |
| Report the MobilizedBodyIndex of body 1 for this Weld constraint. More... | |
| MobilizedBodyIndex | getBody2MobilizedBodyIndex () const |
| Report the MobilizedBodyIndex of body 2 for this Weld constraint. More... | |
| const Transform & | getFrameOnBody1 (const State &) const |
| const Transform & | getFrameOnBody2 (const State &) const |
| Vec6 | getPositionErrors (const State &) const |
| Vec6 | getVelocityErrors (const State &) const |
| Vec6 | getAccelerationErrors (const State &) const |
| Vec6 | getMultipliers (const State &) const |
| const SpatialVec & | getWeldReactionOnBody1 (const State &) const |
| const SpatialVec & | getWeldReactionOnBody2 (const State &) const |
| 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
Six constraint equations.
This constraint enforces coincidence between a frame on one body and a frame on another body. This is a combination of a ConstantOrientation constraint and a Ball constraint. The first three equations correspond to the perpendicularity constraints associated with the orientation constraint, the last three equations are the coincident point conditions.
The constraint is enforced by an internal (non-working) force applied at the spatial location of the frame origin on body 2, on material points of each body that are coincident with that spatial location. Note that this is somewhat asymmetric when the Weld is not properly assembled – it acts as though the contact occurs at the origin of the frame on body 2, not at the origin of the frame on body 1. The orientation constraints on the other hand are symmetric, they are three "constant angle" constraints enforcing perpendicularity between body2's x,y,z axes with body1's y,z,x axes respectively, via an internal (non-working) torque vector applied equal and opposite on each body.
TODO: Although the frame origins can be brought together by the Ball constraint, the perpendicularity conditions can be satisfied with antiparallel axes in addition to the parallel ones we want. Therefore the assembly conditions must include additional (redundant) constraints requiring parallel axes.
Constructor & Destructor Documentation
◆ Weld() [1/3]
| SimTK::Constraint::Weld::Weld | ( | MobilizedBody & | body1, |
| MobilizedBody & | body2 | ||
| ) |
Make the body frame of one body coincident with the body frame of the other body.
◆ Weld() [2/3]
| SimTK::Constraint::Weld::Weld | ( | MobilizedBody & | body1, |
| const Transform & | frame1, | ||
| MobilizedBody & | body2, | ||
| const Transform & | frame2 | ||
| ) |
Make a particular frame attached to one body coincident with a particular frame attached to the other body.
The frames are specified by giving the transform X_BF which expresses the position and orientation of frame F relative to the body frame B.
◆ Weld() [3/3]
|
inline |
Default constructor creates an empty handle.
Member Function Documentation
◆ setAxisDisplayLength()
This is used only for visualization.
Set r <= 0 to disable default frame drawing. Default axis length is r=1. This is a topology-stage variable, not changeable later.
◆ getAxisDisplayLength()
| Real SimTK::Constraint::Weld::getAxisDisplayLength | ( | ) | const |
Report the length being used for display of the frames being connected by this Weld.
If this returns 0 then no geometry is being generated for the frames.
◆ setDefaultFrameOnBody1()
Explicitly set the default value for the frame on body1 which is to be made coincident with a frame on body2.
Note that this is topology-stage value so requires non-const access to the Constraint.
◆ getDefaultFrameOnBody1()
| const Transform& SimTK::Constraint::Weld::getDefaultFrameOnBody1 | ( | ) | const |
Retrieve the default transform for the frame on body 1.
◆ setDefaultFrameOnBody2()
Explicitly set the default value for the frame on body2 which is to be made coincident with a frame on body1.
Note that this is topology-stage value so requires non-const access to the Constraint.
◆ getDefaultFrameOnBody2()
| const Transform& SimTK::Constraint::Weld::getDefaultFrameOnBody2 | ( | ) | const |
Retrieve the default transform for the frame on body 2.
◆ getBody1MobilizedBodyIndex()
| MobilizedBodyIndex SimTK::Constraint::Weld::getBody1MobilizedBodyIndex | ( | ) | const |
Report the MobilizedBodyIndex of body 1 for this Weld constraint.
◆ getBody2MobilizedBodyIndex()
| MobilizedBodyIndex SimTK::Constraint::Weld::getBody2MobilizedBodyIndex | ( | ) | const |
Report the MobilizedBodyIndex of body 2 for this Weld constraint.
◆ getFrameOnBody1()
◆ getFrameOnBody2()
◆ getPositionErrors()
◆ getVelocityErrors()
◆ getAccelerationErrors()
◆ getMultipliers()
◆ getWeldReactionOnBody1()
| const SpatialVec& SimTK::Constraint::Weld::getWeldReactionOnBody1 | ( | const State & | ) | const |
◆ getWeldReactionOnBody2()
| const SpatialVec& SimTK::Constraint::Weld::getWeldReactionOnBody2 | ( | const State & | ) | const |
The documentation for this class was generated from the following file:
