SimTK::MobilizedBody::Gimbal Class Reference
Three mobilities – unrestricted orientation modeled as a 1-2-3 body-fixed Euler angle sequence, though with a singularity when the middle angle is +/- 90 degrees. More...
Inheritance diagram for SimTK::MobilizedBody::Gimbal:
Public Member Functions | |
| Gimbal () | |
| Default constructor provides an empty handle that can be assigned to reference any MobilizedBody::Gimbal. More... | |
| Gimbal (MobilizedBody &parent, const Transform &X_PF, const Body &bodyInfo, const Transform &X_BM, Direction=Forward) | |
| Create a Gimbal mobilizer between an existing parent (inboard) body P and a new child (outboard) body B created by copying the given bodyInfo into a privately-owned Body within the constructed MobilizedBody object. More... | |
| Gimbal (MobilizedBody &parent, const Body &bodyInfo, Direction=Forward) | |
| Abbreviated constructor you can use if the mobilizer frames are coincident with the parent and child body frames. More... | |
| Gimbal & | setDefaultInboardFrame (const Transform &X_PF) |
| Change the default inboard ("fixed") frame F on the parent body of this mobilizer. More... | |
| Gimbal & | setDefaultOutboardFrame (const Transform &X_BM) |
| Change the default outboard ("moving") frame M on this mobilized body (that is, on this mobilizer's child body). More... | |
| Gimbal & | setDefaultRotation (const Rotation &R_FM) |
| Override the default orientation for this mobilizer. More... | |
| Rotation | getDefaultRotation () const |
| Return the default orientation for this mobilizer as a Rotation matrix. More... | |
| Gimbal & | addBodyDecoration (const Transform &X_BD, const DecorativeGeometry &g) |
| Add DecorativeGeometry to the privately-owned Body contained in this MobilizedBody, positioned relative to the body's frame. More... | |
| Gimbal & | addOutboardDecoration (const Transform &X_MD, const DecorativeGeometry &g) |
| Add DecorativeGeometry to the privately-owned Body contained in this MobilizedBody, positioned relative to the mobilizer's M frame on that body. More... | |
| Gimbal & | addInboardDecoration (const Transform &X_FD, const DecorativeGeometry &g) |
| Add DecorativeGeometry to the parent (inboard) body of this mobilizer, positioned relative to the mobilizer's F frame on the parent body. More... | |
| Gimbal & | setDefaultRadius (Real r) |
| This affects the radius of the ball that will be drawn as default visualization geometry for a Gimbal mobilizer. More... | |
| Real | getDefaultRadius () const |
| Get the current value of the default visualization ball radius. More... | |
| const Vec3 & | getDefaultQ () const |
| Obtain the default value for the generalized coordinates q that has been set for this mobilizer. More... | |
| Gimbal & | setDefaultQ (const Vec3 &q) |
| Set the default value for the generalized coordinates q for this mobilizer. More... | |
| const Vec3 & | getQ (const State &state) const |
| Obtain the current value for this mobilizer's generalized coordinates q from the given State, which must be realized through Stage::Model (these are state variables). More... | |
| const Vec3 & | getQDot (const State &state) const |
| Obtain the current value for this mobilizer's generalized coordinate time derivatives qdot from the given State, which must be realized through Stage::Velocity. More... | |
| const Vec3 & | getQDotDot (const State &state) const |
| Obtain the current value for this mobilizer's generalized coordinate second time derivatives qdotdot from the given State, which must be realized through Stage::Acceleration. More... | |
| const Vec3 & | getU (const State &state) const |
| Obtain the current value for this mobilizer's generalized speeds u from the given State, which must be realized through Stage::Model (these are state variables). More... | |
| const Vec3 & | getUDot (const State &state) const |
| Obtain the current value for this mobilizer's generalized accelerations udot (d/dt u) from the given State, which must be realized through Stage::Acceleration. More... | |
| void | setQ (State &state, const Vec3 &q) const |
| Set new values for this mobilizer's generalized coordinates q in the given state. More... | |
| void | setU (State &state, const Vec3 &u) const |
| Set new values for this mobilizer's generalized speeds u in the given state. More... | |
Advanced/Obscure | |
Most users won't use these methods. | |
| const Vec3 & | getMyPartQ (const State &state, const Vector &qlike) const |
| Given a vector in the System's generalized coordinate basis, extract the three q's belonging to this mobilizer. More... | |
| const Vec3 & | getMyPartU (const State &state, const Vector &ulike) const |
| Given a vector in the System's generalized speed basis, extract the three u's belonging to this mobilizer. More... | |
| Vec3 & | updMyPartQ (const State &state, Vector &qlike) const |
| Given a writable vector in the System's generalized coordinate basis, extract a writable reference to the three q's in that vector that belong to this mobilizer. More... | |
| Vec3 & | updMyPartU (const State &state, Vector &ulike) const |
| Given a writable vector in the System's generalized speed basis, extract a writable reference to the three u's in that vector that belong to this mobilizer. More... | |
| Public Member Functions inherited from SimTK::MobilizedBody | |
| MobilizedBody () | |
| The default constructor provides an empty MobilizedBody handle that can be assigned to reference any type of MobilizedBody. More... | |
| MobilizedBody (MobilizedBodyImpl *r) | |
| Internal use only. More... | |
| void | lock (State &state, Motion::Level level=Motion::Position) const |
Lock this mobilizer's position or velocity at its current value, or lock the acceleration to zero, depending on the level parameter. More... | |
| void | lockAt (State &state, Real value, Motion::Level level=Motion::Position) const |
Lock this mobilizer's q, u, or udot to the given scalar value, depending on level. More... | |
| void | lockAt (State &state, const Vector &value, Motion::Level level=Motion::Position) const |
Lock this mobilizer's q, u, or udot to the given Vector value, depending on level. More... | |
| template<int N> | |
| void | lockAt (State &state, const Vec< N > &value, Motion::Level level=Motion::Position) const |
Lock this mobilizer's q, u, or udot to the given Vec<N> value, depending on the level. More... | |
| void | unlock (State &state) const |
| Unlock this mobilizer, returning it to its normal behavior which may be free motion or may be controlled by a Motion object. More... | |
| bool | isLocked (const State &state) const |
Check whether this mobilizer is currently locked in the given state. More... | |
| Motion::Level | getLockLevel (const State &state) const |
Returns the lock level if the mobilizer is locked in the given state, otherwise Motion::NoLevel. More... | |
| Vector | getLockValueAsVector (const State &state) const |
| Return the q, u, or udot value at which this mobilizer is locked, depending on the lock level, as a Vector of the appropriate length. More... | |
| MobilizedBody & | lockByDefault (Motion::Level level=Motion::Position) |
| Change whether this mobilizer is initially locked. More... | |
| bool | isLockedByDefault () const |
| Check whether this mobilizer is to be locked in the default state. More... | |
| Motion::Level | getLockByDefaultLevel () const |
| Returns the level at which the mobilizer is locked by default, if it is locked by default, otherwise Motion::NoLevel. More... | |
| const Transform & | getBodyTransform (const State &state) const |
| Extract from the state cache the already-calculated spatial configuration X_GB of body B's body frame, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const Rotation & | getBodyRotation (const State &state) const |
| Extract from the state cache the already-calculated spatial orientation R_GB of body B's body frame x, y, and z axes expressed in the Ground frame, as the Rotation matrix R_GB. More... | |
| const Vec3 & | getBodyOriginLocation (const State &state) const |
| Extract from the state cache the already-calculated spatial location of body B's body frame origin Bo, measured from the Ground origin Go and expressed in the Ground frame, as the position vector p_GB (== p_GoBo). More... | |
| const Transform & | getMobilizerTransform (const State &state) const |
| At stage Position or higher, return the cross-mobilizer transform X_FM, the body's inboard mobilizer frame M measured and expressed in the parent body's corresponding outboard frame F. More... | |
| const SpatialVec & | getBodyVelocity (const State &state) const |
| Extract from the state cache the already-calculated spatial velocity V_GB of this body's reference frame B, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const Vec3 & | getBodyAngularVelocity (const State &state) const |
| Extract from the state cache the already-calculated inertial angular velocity vector w_GB of this body B, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const Vec3 & | getBodyOriginVelocity (const State &state) const |
| Extract from the state cache the already-calculated inertial linear velocity vector v_GB (more explicitly, v_GBo) of this body B's origin point Bo, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const SpatialVec & | getMobilizerVelocity (const State &state) const |
| At stage Velocity or higher, return the cross-mobilizer velocity V_FM, the relative velocity of this body's "moving" mobilizer frame M in the parent body's corresponding "fixed" frame F, measured and expressed in F. More... | |
| const SpatialVec & | getBodyAcceleration (const State &state) const |
| Extract from the state cache the already-calculated spatial acceleration A_GB of this body's reference frame B, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const Vec3 & | getBodyAngularAcceleration (const State &state) const |
| Extract from the state cache the already-calculated inertial angular acceleration vector b_GB of this body B, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const Vec3 & | getBodyOriginAcceleration (const State &state) const |
| Extract from the state cache the already-calculated inertial linear acceleration vector a_GB (more explicitly, a_GBo) of this body B's origin point Bo, measured with respect to the Ground frame and expressed in the Ground frame. More... | |
| const SpatialVec & | getMobilizerAcceleration (const State &state) const |
| TODO: Not implemented yet – any volunteers? At stage Acceleration, return the cross-mobilizer acceleration A_FM, the relative acceleration of body B's "moving" mobilizer frame M in the parent body's corresponding "fixed" frame F, measured and expressed in F. More... | |
| const MassProperties & | getBodyMassProperties (const State &state) const |
| Return a reference to this body's mass properties in the State cache. More... | |
| const SpatialInertia & | getBodySpatialInertiaInGround (const State &state) const |
| Return a reference to the already-calculated SpatialInertia of this body, taken about the body's origin (not its mass center), and expressed in the Ground frame. More... | |
| Real | getBodyMass (const State &state) const |
| Return the mass of this body. More... | |
| const Vec3 & | getBodyMassCenterStation (const State &state) const |
| Return this body's center of mass station (i.e., the vector fixed in the body, going from body origin to body mass center, expressed in the body frame.) The State must have been realized to Stage::Instance or higher. More... | |
| const UnitInertia & | getBodyUnitInertiaAboutBodyOrigin (const State &state) const |
| Return a reference to this body's unit inertia matrix in the State cache, taken about the body origin and expressed in the body frame. More... | |
| const Transform & | getInboardFrame (const State &state) const |
| Return a reference to this mobilizer's frame F fixed on the parent body P, as the fixed Transform from P's body frame to the frame F fixed to P. More... | |
| const Transform & | getOutboardFrame (const State &state) const |
| Return a reference to this MobilizedBody's mobilizer frame M, as the fixed Transform from this body B's frame to the frame M fixed on B. More... | |
| void | setInboardFrame (State &state, const Transform &X_PF) const |
| TODO: not implemented yet. More... | |
| void | setOutboardFrame (State &state, const Transform &X_BM) const |
| TODO: not implemented yet. More... | |
| int | getNumQ (const State &state) const |
| Return the number of generalized coordinates q currently in use by this mobilizer. More... | |
| int | getNumU (const State &state) const |
| Return the number of generalized speeds u currently in use by this mobilizer. More... | |
| QIndex | getFirstQIndex (const State &state) const |
| Return the global QIndex of the first q for this mobilizer; all the q's range from getFirstQIndex() to QIndex(getFirstQIndex()+getNumQ()-1). More... | |
| UIndex | getFirstUIndex (const State &state) const |
| Return the global UIndex of the first u for this mobilizer; all the u's range from getFirstUIndex() to UIndex(getFirstUIndex()+getNumU()-1). More... | |
| Motion::Method | getQMotionMethod (const State &state) const |
| Determine how generalized coordinate q values are being determined. More... | |
| Motion::Method | getUMotionMethod (const State &state) const |
| Determine how generalized speed u values are being determined. More... | |
| Motion::Method | getUDotMotionMethod (const State &state) const |
| Determine how generalized acceleration udot values are being determined. More... | |
| Real | getOneQ (const State &state, int which) const |
| Return one of the generalized coordinates q from this mobilizer's partition of the matter subsystem's full q vector in the State. More... | |
| Real | getOneU (const State &state, int which) const |
| Return one of the generalized speeds u from this mobilizer's partition of the matter subsystem's full u vector in the State. More... | |
| Vector | getQAsVector (const State &state) const |
| Return as a Vector of length getNumQ() all the generalized coordinates q currently in use by this mobilizer, from this mobilizer's partion in the matter subsystem's full q vector in the State. More... | |
| Vector | getUAsVector (const State &state) const |
| Return as a Vector of length getNumU() all the generalized speeds u currently in use by this mobilizer, from this mobilizer's partion in the matter subsystem's full u vector in the State. More... | |
| Real | getOneQDot (const State &state, int which) const |
| Return one of the generalized coordinate derivatives qdot from this mobilizer's partition of the matter subsystem's full qdot vector in the State cache. More... | |
| Vector | getQDotAsVector (const State &state) const |
| Return as a Vector of length getNumQ() all the generalized coordinate derivatives qdot currently in use by this mobilizer, from this mobilizer's partition in the matter subsystem's full qdot vector in the State cache. More... | |
| Real | getOneUDot (const State &state, int which) const |
| Return one of the generalized accelerations udot from this mobilizer's partition of the matter subsystem's full udot vector in the State cache. More... | |
| Real | getOneQDotDot (const State &state, int which) const |
| Return one of the generalized coordinate second derivatives qdotdot from this mobilizer's partition of the matter subsystem's full qdotdot vector in the State cache. More... | |
| Vector | getUDotAsVector (const State &state) const |
| Return as a Vector of length getNumU() all the generalized accelerations udot currently in use by this mobilizer, from this mobilizer's partion in the matter subsystem's full udot vector in the State cache. More... | |
| Vector | getQDotDotAsVector (const State &state) const |
| Return as a Vector of length getNumQ() all the generalized coordinate second derivatives qdotdot currently in use by this mobilizer, from this mobilizer's partion in the matter subsystem's full qdotdot vector in the State cache. More... | |
| Vector | getTauAsVector (const State &state) const |
| Return the generalized forces tau resulting from prescribed (known) acceleration, corresponding to each of this mobilizer's mobilities, as a Vector of length nu=getNumU(). More... | |
| Real | getOneTau (const State &state, MobilizerUIndex which) const |
Return one of the tau forces resulting from prescribed (known) acceleration, corresponding to one of this mobilizer's mobilities as selected here using the which parameter, numbered from zero to getNumU()-1. More... | |
| void | setOneQ (State &state, int which, Real v) const |
Set one of the generalized coordinates q to value v, in this mobilizer's partition of the matter subsystem's full q vector in the State. More... | |
| void | setOneU (State &state, int which, Real v) const |
Set one of the generalized speeds u to value v, in this mobilizer's partition of the matter subsystem's full u vector in the State. More... | |
| void | setQFromVector (State &state, const Vector &v) const |
Set all of the generalized coordinates q to value v (a Vector of length getNumQ()), in this mobilizer's partition of the matter subsystem's full q vector in the State. More... | |
| void | setUFromVector (State &state, const Vector &v) const |
Set all of the generalized speeds u to value v (a Vector of length getNumU()), in this mobilizer's partition of the matter subsystem's full u vector in the State. More... | |
| void | setQToFitTransform (State &state, const Transform &X_FM) const |
| Adjust this mobilizer's q's to best approximate the supplied Transform which requests a particular relative orientation and translation between the F "fixed" frame and M "moving" frame connected by this mobilizer. More... | |
| void | setQToFitRotation (State &state, const Rotation &R_FM) const |
| Adjust this mobilizer's q's to best approximate the supplied Rotation matrix which requests a particular relative orientation between the "fixed" frame F and "moving" frame M connected by this mobilizer. More... | |
| void | setQToFitTranslation (State &state, const Vec3 &p_FM) const |
| Adjust this mobilizer's q's to best approximate the supplied position vector which requests a particular offset between the origins of the F "fixed" frame and M "moving" frame connected by this mobilizer, with any q's (rotational or translational) being modified if doing so helps satisfy the request. More... | |
| void | setUToFitVelocity (State &state, const SpatialVec &V_FM) const |
Adjust this mobilizer's u's (generalized speeds) to best approximate the supplied spatial velocity V_FM which requests the relative angular and linear velocity between the "fixed" and "moving" frames connected by this mobilizer. More... | |
| void | setUToFitAngularVelocity (State &state, const Vec3 &w_FM) const |
Adjust this mobilizer's u's (generalized speeds) to best approximate the supplied angular velocity w_FM which requests a particular relative angular between the "fixed" and "moving" frames connected by this mobilizer. More... | |
| void | setUToFitLinearVelocity (State &state, const Vec3 &v_FM) const |
Adjust any of this mobilizer's u's (generalized speeds) to best approximate the supplied linear velocity v_FM which requests a particular velocity for the "moving" frame M origin in the "fixed" frame F on the parent where these are the frames connected by this mobilizer. More... | |
| SpatialVec | getHCol (const State &state, MobilizerUIndex ux) const |
| Expert use only: obtain a column of the hinge matrix H corresponding to one of this mobilizer's mobilities (actually a column of H_PB_G; what Jain calls H* and Schwieters calls H^T). More... | |
| SpatialVec | getH_FMCol (const State &state, MobilizerUIndex ux) const |
| Expert use only: obtain a column of the mobilizer-local hinge matrix H_FM which maps generalized speeds u to cross-mobilizer spatial velocity V_FM via V_FM=H_FM*u. More... | |
| Transform | findBodyTransformInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return X_AB, the spatial transform giving this body B's frame in body A's frame. More... | |
| Rotation | findBodyRotationInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return R_AB, the rotation matrix giving this body B's axes in body A's frame. More... | |
| Vec3 | findBodyOriginLocationInAnotherBody (const State &state, const MobilizedBody &toBodyA) const |
| Return the station on another body A (that is, a point measured and expressed in A) that is currently coincident in space with the origin Bo of this body B. More... | |
| SpatialVec | findBodyVelocityInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the angular and linear velocity of body B's frame in body A's frame, expressed in body A, and arranged as a SpatialVec. More... | |
| Vec3 | findBodyAngularVelocityInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the angular velocity w_AB of body B's frame in body A's frame, expressed in body A. More... | |
| Vec3 | findBodyOriginVelocityInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the velocity of body B's origin point in body A's frame, expressed in body A. More... | |
| SpatialVec | findBodyAccelerationInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the angular and linear acceleration of body B's frame in body A's frame, expressed in body A, and arranged as a SpatialVec. More... | |
| Vec3 | findBodyAngularAccelerationInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the angular acceleration of body B's frame in body A's frame, expressed in body A. More... | |
| Vec3 | findBodyOriginAccelerationInAnotherBody (const State &state, const MobilizedBody &inBodyA) const |
| Return the acceleration of body B's origin point in body A's frame, expressed in body A. More... | |
| SpatialVec | findMobilizerReactionOnBodyAtMInGround (const State &state) const |
| Return the spatial reaction force (moment and force) applied by the mobilizer to body B at the location of the mobilizer frame M (fixed to body B, but not necessarily at the body frame origin), expressed in Ground. More... | |
| SpatialVec | findMobilizerReactionOnBodyAtOriginInGround (const State &state) const |
| Return the spatial reaction force (moment and force) applied by the mobilizer to body B but shifted to the B frame origin, and expressed in Ground. More... | |
| SpatialVec | findMobilizerReactionOnParentAtFInGround (const State &state) const |
| Return the spatial reaction force (moment and force) applied by the mobilizer to the parent (inboard) body P at the location of the inboard "fixed" mobilizer frame F (fixed to body P, but not necessarily at the P frame origin), expressed in Ground. More... | |
| SpatialVec | findMobilizerReactionOnParentAtOriginInGround (const State &state) const |
| Return the spatial reaction force (moment and force) applied by the mobilizer to the parent (inboard) body P at the location of the P frame origin, and expressed in Ground. More... | |
| Vec3 | findStationLocationInGround (const State &state, const Vec3 &stationOnB) const |
| Return the Cartesian (ground) location that is currently coincident with a station (point) S fixed on body B. More... | |
| Vec3 | findStationLocationInAnotherBody (const State &state, const Vec3 &stationOnB, const MobilizedBody &toBodyA) const |
| Given a station S on this body B, return the location on another body A which is at the same location in space. More... | |
| Vec3 | findStationVelocityInGround (const State &state, const Vec3 &stationOnB) const |
| Given a station fixed on body B, return its inertial (Cartesian) velocity, that is, its velocity relative to the Ground frame, expressed in the Ground frame. More... | |
| Vec3 | findStationVelocityInAnotherBody (const State &state, const Vec3 &stationOnBodyB, const MobilizedBody &inBodyA) const |
| Return the velocity of a station S fixed on body B, in body A's frame, expressed in body A. More... | |
| Vec3 | findStationAccelerationInGround (const State &state, const Vec3 &stationOnB) const |
| Given a station fixed on body B, return its inertial (Cartesian) acceleration, that is, its acceleration relative to the ground frame, expressed in the ground frame. More... | |
| Vec3 | findStationAccelerationInAnotherBody (const State &state, const Vec3 &stationOnBodyB, const MobilizedBody &inBodyA) const |
| Return the acceleration of a station S fixed on body B, in another body A's frame, expressed in body A. More... | |
| void | findStationLocationAndVelocityInGround (const State &state, const Vec3 &locationOnB, Vec3 &locationOnGround, Vec3 &velocityInGround) const |
| It is cheaper to calculate a station's ground location and velocity together than to do them separately. More... | |
| void | findStationLocationVelocityAndAccelerationInGround (const State &state, const Vec3 &locationOnB, Vec3 &locationOnGround, Vec3 &velocityInGround, Vec3 &accelerationInGround) const |
| It is cheaper to calculate a station's ground location, velocity, and acceleration together than to do them separately. More... | |
| Vec3 | findMassCenterLocationInGround (const State &state) const |
| Return the Cartesian (ground) location of this body B's mass center. More... | |
| Vec3 | findMassCenterLocationInAnotherBody (const State &state, const MobilizedBody &toBodyA) const |
| Return the point of another body A that is currently coincident in space with the mass center CB of this body B. More... | |
| Vec3 | findStationAtGroundPoint (const State &state, const Vec3 &locationInG) const |
| Return the station (point) S of this body B that is coincident with the given Ground location. More... | |
| Vec3 | findStationAtAnotherBodyStation (const State &state, const MobilizedBody &fromBodyA, const Vec3 &stationOnA) const |
| Return the station (point) on this body B that is coincident with the given station on another body A. More... | |
| Vec3 | findStationAtAnotherBodyOrigin (const State &state, const MobilizedBody &fromBodyA) const |
| Return the station S of this body that is currently coincident in space with the origin Ao of another body A. More... | |
| Vec3 | findStationAtAnotherBodyMassCenter (const State &state, const MobilizedBody &fromBodyA) const |
| Return the station S of this body that is currently coincident in space with the mass center Ac of another body A. More... | |
| Transform | findFrameTransformInGround (const State &state, const Transform &frameOnB) const |
| Return the current Ground-frame pose (position and orientation) of a frame F that is fixed to body B. More... | |
| SpatialVec | findFrameVelocityInGround (const State &state, const Transform &frameOnB) const |
| Return the current Ground-frame spatial velocity V_GF (that is, angular and linear velocity) of a frame F that is fixed to body B. More... | |
| SpatialVec | findFrameAccelerationInGround (const State &state, const Transform &frameOnB) const |
| Return the current Ground-frame spatial acceleration A_GF (that is, angular and linear acceleration) of a frame F that is fixed to body B. More... | |
| Vec3 | expressVectorInGroundFrame (const State &state, const Vec3 &vectorInB) const |
| Re-express a vector expressed in this body B's frame into the same vector in G, by applying only a rotation. More... | |
| Vec3 | expressGroundVectorInBodyFrame (const State &state, const Vec3 &vectorInG) const |
| Re-express a vector expressed in Ground into the same vector expressed in this body B, by applying only rotation. More... | |
| Vec3 | expressVectorInAnotherBodyFrame (const State &state, const Vec3 &vectorInB, const MobilizedBody &inBodyA) const |
| Re-express a vector expressed in this body B into the same vector expressed in body A, by applying only a rotation. More... | |
| MassProperties | expressMassPropertiesInGroundFrame (const State &state) const |
| Re-express this body B's mass properties in Ground by applying only a rotation, not a shift of reference point. More... | |
| MassProperties | expressMassPropertiesInAnotherBodyFrame (const State &state, const MobilizedBody &inBodyA) const |
| Re-express this body B's mass properties in another body A's frame by applying only a rotation, not a shift of reference point. More... | |
| SpatialMat | calcBodySpatialInertiaMatrixInGround (const State &state) const |
| Return the mass properties of body B, measured from and about the B origin Bo, but expressed in Ground and then returned as a Spatial Inertia Matrix. More... | |
| Inertia | calcBodyCentralInertia (const State &state, MobilizedBodyIndex objectBodyB) const |
| Return the central inertia for body B, that is, the inertia taken about body B's mass center Bc, and expressed in B. More... | |
| Inertia | calcBodyInertiaAboutAnotherBodyStation (const State &state, const MobilizedBody &inBodyA, const Vec3 &aboutLocationOnBodyA) const |
| Return the inertia of this body B, taken about an arbitrary point PA of body A, and expressed in body A. More... | |
| SpatialVec | calcBodyMomentumAboutBodyOriginInGround (const State &state) |
| Calculate body B's momentum (angular, linear) measured and expressed in Ground, but taken about the body origin Bo. More... | |
| SpatialVec | calcBodyMomentumAboutBodyMassCenterInGround (const State &state) const |
| Calculate body B's momentum (angular, linear) measured and expressed in Ground, but taken about the body mass center Bc. More... | |
| Real | calcStationToStationDistance (const State &state, const Vec3 &locationOnBodyB, const MobilizedBody &bodyA, const Vec3 &locationOnBodyA) const |
| Calculate the distance from a station PB on body B to a station PA on body A. More... | |
| Real | calcStationToStationDistanceTimeDerivative (const State &state, const Vec3 &locationOnBodyB, const MobilizedBody &bodyA, const Vec3 &locationOnBodyA) const |
| Calculate the time rate of change of distance from a fixed point PB on body B to a fixed point PA on body A. More... | |
| Real | calcStationToStationDistance2ndTimeDerivative (const State &state, const Vec3 &locationOnBodyB, const MobilizedBody &bodyA, const Vec3 &locationOnBodyA) const |
| Calculate the second time derivative of distance from a fixed point PB on body B to a fixed point PA on body A. More... | |
| Vec3 | calcBodyMovingPointVelocityInBody (const State &state, const Vec3 &locationOnBodyB, const Vec3 &velocityOnBodyB, const MobilizedBody &inBodyA) const |
| TODO: not implemented yet – any volunteers? Return the velocity of a point P moving on body B, in body A's frame, expressed in body A. More... | |
| Vec3 | calcBodyMovingPointAccelerationInBody (const State &state, const Vec3 &locationOnBodyB, const Vec3 &velocityOnBodyB, const Vec3 &accelerationOnBodyB, const MobilizedBody &inBodyA) const |
| TODO: not implemented yet – any volunteers? Return the velocity of a point P moving (and possibly accelerating) on body B, in body A's frame, expressed in body A. More... | |
| Real | calcMovingPointToPointDistanceTimeDerivative (const State &state, const Vec3 &locationOnBodyB, const Vec3 &velocityOnBodyB, const MobilizedBody &bodyA, const Vec3 &locationOnBodyA, const Vec3 &velocityOnBodyA) const |
| TODO: not implemented yet – any volunteers? Calculate the time rate of change of distance from a moving point PB on body B to a moving point PA on body A. More... | |
| Real | calcMovingPointToPointDistance2ndTimeDerivative (const State &state, const Vec3 &locationOnBodyB, const Vec3 &velocityOnBodyB, const Vec3 &accelerationOnBodyB, const MobilizedBody &bodyA, const Vec3 &locationOnBodyA, const Vec3 &velocityOnBodyA, const Vec3 &accelerationOnBodyA) const |
| TODO: not implemented yet – any volunteers? Calculate the second time derivative of distance from a moving point PB on body B to a moving point PA on body A. More... | |
| const Body & | getBody () const |
| Return a const reference to the Body contained within this MobilizedBody. More... | |
| Body & | updBody () |
| Return a writable reference to the Body contained within this MobilizedBody. More... | |
| MobilizedBody & | setBody (const Body &) |
| Replace the Body contained within this MobilizedBody with a new one. More... | |
| int | addBodyDecoration (const Transform &X_BD, const DecorativeGeometry &geometry) |
| Convenience method to add DecorativeGeometry specified relative to the new (outboard) body's reference frame B. More... | |
| int | addBodyDecoration (const DecorativeGeometry &geometry) |
Convenience method for use when the geometry is supplied in the body frame. More... | |
| int | addOutboardDecoration (const Transform &X_MD, const DecorativeGeometry &geometry) |
| Add decorative geometry specified relative to the outboard mobilizer frame M attached to body B, and associated with the mobilizer rather than the body. More... | |
| int | getNumOutboardDecorations () const |
| Return the count of decorations added with addOutboardDecoration(). More... | |
| const DecorativeGeometry & | getOutboardDecoration (int i) const |
| Return a const reference to the i'th outboard decoration. More... | |
| DecorativeGeometry & | updOutboardDecoration (int i) |
| Return a writable reference to the i'th outboard decoration. More... | |
| int | addInboardDecoration (const Transform &X_FD, const DecorativeGeometry &geometry) |
| Add decorative geometry specified relative to the inboard mobilizer frame F attached to the parent body P, and associated with the mobilizer rather than the body. More... | |
| int | getNumInboardDecorations () const |
| Return the count of decorations added with addInboardDecoration(). More... | |
| const DecorativeGeometry & | getInboardDecoration (int i) const |
| Return a const reference to the i'th inboard decoration. More... | |
| DecorativeGeometry & | updInboardDecoration (int i) |
| Return a writable reference to the i'th inboard decoration. More... | |
| MobilizedBody & | setDefaultMassProperties (const MassProperties &m) |
If the contained Body can have its mass properties set to the supplied value m its mass properties are changed, otherwise the method fails. More... | |
| const MassProperties & | getDefaultMassProperties () const |
| Return the mass properties of the Body stored within this MobilizedBody. More... | |
| void | adoptMotion (Motion &ownerHandle) |
| Provide a unique Motion object for this MobilizedBody. More... | |
| void | clearMotion () |
| If there is a Motion object associated with this MobilizedBody it is removed; otherwise, nothing happens. More... | |
| bool | hasMotion () const |
| Check whether this MobilizedBody has an associated Motion object. More... | |
| const Motion & | getMotion () const |
| If there is a Motion object associated with this MobilizedBody, this returns a const reference to it. More... | |
| MobilizedBody & | setDefaultInboardFrame (const Transform &X_PF) |
| Change this mobilizer's frame F on the parent body P. More... | |
| MobilizedBody & | setDefaultOutboardFrame (const Transform &X_BM) |
| Change this mobilizer's frame M fixed on this (the outboard) body B. More... | |
| const Transform & | getDefaultInboardFrame () const |
| Return a reference to this mobilizer's default for the frame F fixed on the parent (inboard) body P, as the fixed Transform from P's body frame to the frame F fixed to P. More... | |
| const Transform & | getDefaultOutboardFrame () const |
| Return a reference to this MobilizedBody's default for mobilizer frame M, as the fixed Transform from this body B's frame to the frame M fixed on B. More... | |
| operator MobilizedBodyIndex () const | |
| This is an implicit conversion from MobilizedBody to MobilizedBodyIndex when needed. More... | |
| MobilizedBodyIndex | getMobilizedBodyIndex () const |
| Return the MobilizedBodyIndex of this MobilizedBody within the owning SimbodyMatterSubsystem. More... | |
| const MobilizedBody & | getParentMobilizedBody () const |
| Return a reference to the MobilizedBody serving as the parent body of the current MobilizedBody. More... | |
| const MobilizedBody & | getBaseMobilizedBody () const |
| Return a reference to this MobilizedBody's oldest ancestor other than Ground, or return Ground if this MobilizedBody is Ground. More... | |
| const SimbodyMatterSubsystem & | getMatterSubsystem () const |
| Obtain a reference to the SimbodyMatterSubsystem which contains this MobilizedBody. More... | |
| SimbodyMatterSubsystem & | updMatterSubsystem () |
| Obtain a writable reference to the SimbodyMatterSubsystem which contains this MobilizedBody. More... | |
| bool | isInSubsystem () const |
| Determine whether the current MobilizedBody object is owned by a matter subsystem. More... | |
| bool | isInSameSubsystem (const MobilizedBody &mobod) const |
Determine whether a given MobilizedBody mobod is in the same matter subsystem as the current body. More... | |
| bool | isSameMobilizedBody (const MobilizedBody &mobod) const |
Determine whether a given MobilizedBody mobod is the same MobilizedBody as this one. More... | |
| bool | isGround () const |
| Determine whether this MobilizedBody is Ground, meaning that it is actually body 0 of some matter subsytem, not just that its body type is Ground. More... | |
| int | getLevelInMultibodyTree () const |
| Return this mobilized body's level in the tree of bodies, starting with Ground at 0, mobilized bodies directly connected to Ground at 1, mobilized bodies directly connected to those at 2, etc. More... | |
| MobilizedBody & | cloneForNewParent (MobilizedBody &parent) const |
| Create a new MobilizedBody which is identical to this one, except that it has a different parent (and consequently might belong to a different MultibodySystem). More... | |
| Real | getOneFromQPartition (const State &state, int which, const Vector &qlike) const |
| This utility selects one of the q's (generalized coordinates) associated with this mobilizer from a supplied "q-like" Vector, meaning a Vector which is the same length as the Vector of q's for the containing matter subsystem. More... | |
| Real & | updOneFromQPartition (const State &state, int which, Vector &qlike) const |
| This utility returns a writable reference to one of the q's (generalized coordinates) associated with this mobilizer from a supplied "q-like" Vector, meaning a Vector which is the same length as the Vector of q's for the containing matter subsystem. More... | |
| Real | getOneFromUPartition (const State &state, int which, const Vector &ulike) const |
| This utility selects one of the u's (generalized speeds) associated with this mobilizer from a supplied "u-like" Vector, meaning a Vector which is the same length as the Vector of u's for the containing matter subsystem. More... | |
| Real & | updOneFromUPartition (const State &state, int which, Vector &ulike) const |
| This utility returns a writable reference to one of the u's (generalized speeds) associated with this mobilizer from a supplied "u-like" Vector, meaning a Vector which is the same length as the Vector of u's for the containing matter subsystem. More... | |
| void | applyOneMobilityForce (const State &state, int which, Real f, Vector &mobilityForces) const |
This utility adds in the supplied generalized force f (a scalar) to the appropriate slot of the supplied mobilityForces Vector, which is a "u-like" Vector. More... | |
| void | convertQForceToUForce (const State &state, const Array_< Real, MobilizerQIndex > &fq, Array_< Real, MobilizerUIndex > &fu) const |
| Given a generalized force in the q-space of this mobilizer, convert it to the equivalent generalized mobility force (u-space force). More... | |
| void | applyBodyForce (const State &state, const SpatialVec &spatialForceInG, Vector_< SpatialVec > &bodyForcesInG) const |
This utility adds in the supplied spatial force spatialForceInG (consisting of a torque vector, and a force vector to be applied at the current body's origin) to the appropriate slot of the supplied bodyForcesInG Vector. More... | |
| void | applyBodyTorque (const State &state, const Vec3 &torqueInG, Vector_< SpatialVec > &bodyForcesInG) const |
This utility adds in the supplied pure torque torqueInG to the appropriate slot of the supplied bodyForcesInG Vector. More... | |
| void | applyForceToBodyPoint (const State &state, const Vec3 &pointInB, const Vec3 &forceInG, Vector_< SpatialVec > &bodyForcesInG) const |
This utility adds in the supplied force forceInG applied at a point pointInB to the appropriate slot of the supplied bodyForcesInG Vector. More... | |
| Public Member Functions inherited from SimTK::PIMPLHandle< MobilizedBody, MobilizedBodyImpl, 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 MobilizedBody &other) const |
| Determine whether the supplied handle is the same object as "this" PIMPLHandle. More... | |
| void | disown (MobilizedBody &newOwner) |
| Give up ownership of the implementation to an empty handle. More... | |
| PIMPLHandle & | referenceAssign (const MobilizedBody &source) |
| "Copy" assignment but with shallow (pointer) semantics. More... | |
| PIMPLHandle & | copyAssign (const MobilizedBody &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 MobilizedBodyImpl & | getImpl () const |
| Get a const reference to the implementation associated with this Handle. More... | |
| MobilizedBodyImpl & | 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::MobilizedBody | |
| enum | Direction { Forward = 0, Reverse = 1 } |
| Constructors can take an argument of this type to indicate that the mobilizer is being defined in the reverse direction, meaning from the outboard (child) body to the inboard (parent) body. More... | |
| typedef Pin | Torsion |
| Synonym for Pin mobilizer. More... | |
| typedef Pin | Revolute |
| Synonym for Pin mobilizer. More... | |
| typedef Slider | Prismatic |
| Synonym for Slider mobilizer. More... | |
| typedef Translation | Cartesian |
| Synonym for Translation mobilizer. More... | |
| typedef Translation | CartesianCoords |
| Synonym for Translation mobilizer. More... | |
| typedef BendStretch | PolarCoords |
| Synonym for BendStretch mobilizer. More... | |
| typedef Ball | Orientation |
| Synonym for Ball mobilizer. More... | |
| typedef Ball | Spherical |
| Synonym for Ball mobilizer. More... | |
| Public Types inherited from SimTK::PIMPLHandle< MobilizedBody, MobilizedBodyImpl, true > | |
| typedef PIMPLHandle< MobilizedBody, MobilizedBodyImpl, PTR > | HandleBase |
| typedef HandleBase | ParentHandle |
| Protected Member Functions inherited from SimTK::PIMPLHandle< MobilizedBody, MobilizedBodyImpl, true > | |
| PIMPLHandle () | |
| The default constructor makes this an empty handle. More... | |
| PIMPLHandle (MobilizedBodyImpl *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 (MobilizedBodyImpl *p) |
| Set the implementation for this empty handle. More... | |
| bool | hasSameImplementation (const MobilizedBody &other) const |
| Determine whether the supplied handle is a reference to the same implementation object as is referenced by "this" PIMPLHandle. More... | |
| Related Functions inherited from SimTK::MobilizedBody | |
| typedef MobilizedBody | Mobod |
| Mobod is the approved abbreviation for MobilizedBody. Feel free to use it if you get tired of typing or seeing the full name. More... | |
Detailed Description
Three mobilities – unrestricted orientation modeled as a 1-2-3 body-fixed Euler angle sequence, though with a singularity when the middle angle is +/- 90 degrees.
Use MobilizedBody::Ball for a similar joint that is free of singularities.
This mobilizer does not provide any translation, so the parent's F frame and child's M frame origins will always be coincident. (MobilizedBody::Bushing is defined like Gimbal but adds translation.) When q0=q1=q2=0, the F and M frames are aligned. Then the generalized coordinates q should be interpreted as a series of rotation angles in radians: q0 is a rotation about the x axis, then q1 is a rotation about the now-rotated y axis, and then q2 is a rotation about the now twice-rotated z axis. The generalized speeds u for the Gimbal mobilizer are the time derivatives of the generalized coordinates, that is, u=qdot. Note that this is different than the choice of generalized speeds used for MobilizedBody::Ball, where the angular velocity vector is used as the three generalized speeds. (Euler angle derivatives are not the same as angular velocity, except when q=0.)
While this mobilizer provides arbitrary orientation, the Euler angle derivatives are singular when q1 (the middle rotation) is near +/- Pi/2. That means you should not attempt to do any dynamics in that configuration; if you can't be sure the motion will remain away from that region, you should use a MobilizedBody::Ball instead, which uses quaternions to ensure singularity-free rotation.
Here is another way to describe the meaning of a Gimbal mobilizer: A Gimbal between frames F and M is exactly equivalent to a series of three pin joints using two massless intermediate bodies B1 and B2. The first pin joint rotates about the common Fx and B1x axes. The second rotates about the common B1y and B2y axes. The last one rotates about the common B2z and Mz axes. Other than performance (which is somewhat better if you use the Gimbal), the pins-and-intermediate bodies system generates exactly the same generalized coordinates and generalized speeds as the Gimbal.
- See also
- MobilizedBody::Ball, MobilizedBody::Gimbal
Constructor & Destructor Documentation
◆ Gimbal() [1/3]
|
inline |
Default constructor provides an empty handle that can be assigned to reference any MobilizedBody::Gimbal.
◆ Gimbal() [2/3]
| SimTK::MobilizedBody::Gimbal::Gimbal | ( | MobilizedBody & | parent, |
| const Transform & | X_PF, | ||
| const Body & | bodyInfo, | ||
| const Transform & | X_BM, | ||
| Direction | = Forward |
||
| ) |
Create a Gimbal mobilizer between an existing parent (inboard) body P and a new child (outboard) body B created by copying the given bodyInfo into a privately-owned Body within the constructed MobilizedBody object.
Specify the mobilizer frames F fixed to parent P and M fixed to child B.
◆ Gimbal() [3/3]
| SimTK::MobilizedBody::Gimbal::Gimbal | ( | MobilizedBody & | parent, |
| const Body & | bodyInfo, | ||
| Direction | = Forward |
||
| ) |
Abbreviated constructor you can use if the mobilizer frames are coincident with the parent and child body frames.
Member Function Documentation
◆ setDefaultInboardFrame()
Change the default inboard ("fixed") frame F on the parent body of this mobilizer.
The supplied frame is given as a Transform from the parent body's frame P and replaces the F frame specified in the constructor. This is a topological change, meaning that you must call realizeTopology() again if you call this method.
◆ setDefaultOutboardFrame()
Change the default outboard ("moving") frame M on this mobilized body (that is, on this mobilizer's child body).
The supplied frame is given as a Transform from the child body's frame B and replaces the M frame specified in the constructor. This is a topological change, meaning that you must call realizeTopology() again if you use this method.
◆ setDefaultRotation()
Override the default orientation for this mobilizer.
Normally the default is q=0. Here you can provide a Rotation giving the default orientation of the mobilizer's M frame in the parent body's F frame. That orientation will be converted to a body fixed 1-2-3 Euler sequence and used to set the default values for the generalized coordinates q that will appear in a State that has just been created by a realizeTopology() call. This is a topological change, meaning that you must call realizeTopology() again if you use this method.
◆ getDefaultRotation()
|
inline |
Return the default orientation for this mobilizer as a Rotation matrix.
This is the initial orientation of the mobilizer's M frame in the parent body's F frame that you will see in a State that has just been created via a realizeTopology() call. This is a topological change, meaning that you must call realizeTopology() again if you use this method.
◆ addBodyDecoration()
|
inline |
Add DecorativeGeometry to the privately-owned Body contained in this MobilizedBody, positioned relative to the body's frame.
◆ addOutboardDecoration()
|
inline |
Add DecorativeGeometry to the privately-owned Body contained in this MobilizedBody, positioned relative to the mobilizer's M frame on that body.
◆ addInboardDecoration()
|
inline |
Add DecorativeGeometry to the parent (inboard) body of this mobilizer, positioned relative to the mobilizer's F frame on the parent body.
◆ setDefaultRadius()
This affects the radius of the ball that will be drawn as default visualization geometry for a Gimbal mobilizer.
It has no effect whatsoever on simulation or other computations.
◆ getDefaultRadius()
| Real SimTK::MobilizedBody::Gimbal::getDefaultRadius | ( | ) | const |
Get the current value of the default visualization ball radius.
◆ getDefaultQ()
| const Vec3& SimTK::MobilizedBody::Gimbal::getDefaultQ | ( | ) | const |
Obtain the default value for the generalized coordinates q that has been set for this mobilizer.
The value is returned as a 3-vector but note that the returned quantity is not a vector; it is a body fixed 1-2-3 Euler angle sequence in radians. The default is q=0 unless overridden.
- See also
- getDefaultRotation()
◆ setDefaultQ()
Set the default value for the generalized coordinates q for this mobilizer.
The value is given as a 3-vector but note that the supplied quantity is not a vector; it is a body fixed 1-2-3 Euler angle sequence in radians. The default is q=0 unless overridden.
- See also
- getDefaultRotation()
◆ getQ()
Obtain the current value for this mobilizer's generalized coordinates q from the given State, which must be realized through Stage::Model (these are state variables).
◆ getQDot()
Obtain the current value for this mobilizer's generalized coordinate time derivatives qdot from the given State, which must be realized through Stage::Velocity.
These are Euler angle time derivatives and, for the Gimbal mobilizer, have the same numerical values as the generalized speeds u.
◆ getQDotDot()
Obtain the current value for this mobilizer's generalized coordinate second time derivatives qdotdot from the given State, which must be realized through Stage::Acceleration.
These are Euler angle second time derivatives and, for the Gimbal mobilizer, have the same numerical value as the generalized accelerations udot.
◆ getU()
Obtain the current value for this mobilizer's generalized speeds u from the given State, which must be realized through Stage::Model (these are state variables).
For the Gimbal joint, these are the time derivatives of q, that is, qdot=u.
◆ getUDot()
Obtain the current value for this mobilizer's generalized accelerations udot (d/dt u) from the given State, which must be realized through Stage::Acceleration.
For the Gimbal joint, these are the time derivatives of qdot, that is, qdotdot=udot.
◆ setQ()
Set new values for this mobilizer's generalized coordinates q in the given state.
This invalidates Stage::Position and above. The new value is given as a 3-vector, but is interpreted as a body fixed 1-2-3 Euler angle sequence in radians.
◆ setU()
Set new values for this mobilizer's generalized speeds u in the given state.
This invalidates Stage::Velocity and above. The new value is given as a 3-vector, but is interpreted as the time derivatives of a body fixed 1-2-3 Euler angle sequence in radians/time.
◆ getMyPartQ()
| const Vec3& SimTK::MobilizedBody::Gimbal::getMyPartQ | ( | const State & | state, |
| const Vector & | qlike | ||
| ) | const |
Given a vector in the System's generalized coordinate basis, extract the three q's belonging to this mobilizer.
◆ getMyPartU()
| const Vec3& SimTK::MobilizedBody::Gimbal::getMyPartU | ( | const State & | state, |
| const Vector & | ulike | ||
| ) | const |
Given a vector in the System's generalized speed basis, extract the three u's belonging to this mobilizer.
◆ updMyPartQ()
Given a writable vector in the System's generalized coordinate basis, extract a writable reference to the three q's in that vector that belong to this mobilizer.
◆ updMyPartU()
Given a writable vector in the System's generalized speed basis, extract a writable reference to the three u's in that vector that belong to this mobilizer.
The documentation for this class was generated from the following file:
