chrono::ChLinkRevoluteSpherical Class Reference

Description

Composite revolute-spherical joint between two two bodies.

This joint is defined through a point and direction on the first body (the revolute side), a point on the second body (the spherical side), and a distance. Kinematically, the two points are maintained at the prescribed distance while the vector between the two points is always perpendicular to the provided direction of the revolute joint.

#include <ChLinkRevoluteSpherical.h>

Inheritance diagram for chrono::ChLinkRevoluteSpherical:
Collaboration diagram for chrono::ChLinkRevoluteSpherical:

Public Member Functions

 ChLinkRevoluteSpherical (const ChLinkRevoluteSpherical &other)
 
virtual ChLinkRevoluteSphericalClone () const override
 "Virtual" copy constructor (covariant return type).
 
virtual unsigned int GetNumConstraintsBilateral () override
 Get the number of (bilateral) constraints introduced by this joint.
 
const ChVector3dGetPoint1Rel () const
 Get the point on m_body1 (revolute side), expressed in body 1 coordinate system.
 
const ChVector3dGetDir1Rel () const
 Get the direction of the revolute joint, expressed in body 1 coordinate system.
 
const ChVector3dGetPoint2Rel () const
 Get the point on m_body2 (spherical side), expressed in body 2 coordinate system.
 
double GetImposedDistance () const
 Get the imposed distance (length of massless connector).
 
double GetCurrentDistance () const
 Get the current distance between the two points.
 
ChVector3d GetPoint1Abs () const
 Get the point on m_body1 (revolute side), expressed in absolute coordinate system.
 
ChVector3d GetDir1Abs () const
 Get the direction of the revolute joint, expressed in absolute coordinate system.
 
ChVector3d GetPoint2Abs () const
 Get the point on m_body2 (spherical side), expressed in absolute coordinate system.
 
virtual ChFrame GetFrame1Rel () const override
 Get the link frame 1, relative to body 1. More...
 
virtual ChFrame GetFrame2Rel () const override
 Get the link frame 2, relative to body 2. More...
 
virtual ChWrenchd GetReaction1 () const override
 Get the reaction force and torque on the 1st body, expressed in the link frame 1.
 
virtual ChWrenchd GetReaction2 () const override
 Get the reaction force and torque on the 2nd body, expressed in the link frame 2.
 
virtual ChVectorDynamic GetConstraintViolation () const override
 Get the joint violation (residuals of the constraint equations)
 
void Initialize (std::shared_ptr< ChBody > body1, std::shared_ptr< ChBody > body2, const ChCoordsys<> &csys, double distance)
 Initialize this joint by specifying the two bodies to be connected, a coordinate system specified in the absolute frame, and the distance of the massless connector. More...
 
void Initialize (std::shared_ptr< ChBody > body1, std::shared_ptr< ChBody > body2, bool local, const ChVector3d &pos1, const ChVector3d &dir1, const ChVector3d &pos2, bool auto_distance=true, double distance=0)
 Initialize this joint by specifying the two bodies to be connected, a point and a direction on body1 defining the revolute joint, and a point on the second body defining the spherical joint. More...
 
virtual void Update (double time, bool update_assets=true) override
 Perform the update of this joint at the specified time: compute jacobians, constraint violations, etc. More...
 
virtual void ArchiveOut (ChArchiveOut &archive_out) override
 Method to allow serialization of transient data to archives.
 
virtual void ArchiveIn (ChArchiveIn &archive_in) override
 Method to allow deserialization of transient data from archives. More...
 
- Public Member Functions inherited from chrono::ChPhysicsItem
 ChPhysicsItem (const ChPhysicsItem &other)
 
ChSystemGetSystem () const
 Get the pointer to the parent ChSystem().
 
virtual void SetSystem (ChSystem *m_system)
 Set the pointer to the parent ChSystem(). More...
 
void AddVisualModel (std::shared_ptr< ChVisualModel > model)
 Add an (optional) visualization model. More...
 
std::shared_ptr< ChVisualModelGetVisualModel () const
 Access the visualization model (if any). More...
 
void AddVisualShape (std::shared_ptr< ChVisualShape > shape, const ChFrame<> &frame=ChFrame<>())
 Add the specified visual shape to the visualization model. More...
 
std::shared_ptr< ChVisualShapeGetVisualShape (unsigned int i) const
 Access the specified visualization shape in the visualization model (if any). More...
 
void AddVisualShapeFEA (std::shared_ptr< ChVisualShapeFEA > shapeFEA)
 Add the specified FEA visualization object to the visualization model. More...
 
std::shared_ptr< ChVisualShapeFEAGetVisualShapeFEA (unsigned int i) const
 Access the specified FEA visualization object in the visualization model (if any). More...
 
virtual unsigned int GetNumVisualModelClones () const
 Return the number of clones of the visual model associated with this physics item. More...
 
void AddCamera (std::shared_ptr< ChCamera > camera)
 Attach a ChCamera to this physical item. More...
 
std::vector< std::shared_ptr< ChCamera > > GetCameras () const
 Get the set of cameras attached to this physics item.
 
virtual bool IsCollisionEnabled () const
 Tell if the object is subject to collision. More...
 
virtual void AddCollisionModelsToSystem (ChCollisionSystem *coll_sys) const
 Add to the provided collision system any collision models managed by this physics item. More...
 
virtual void RemoveCollisionModelsFromSystem (ChCollisionSystem *coll_sys) const
 Remove from the provided collision system any collision models managed by this physics item. More...
 
virtual void SyncCollisionModels ()
 Synchronize the position and bounding box of any collsion models managed by this physics item.
 
virtual ChAABB GetTotalAABB ()
 Get the entire AABB axis-aligned bounding box of the object. More...
 
virtual void GetCenter (ChVector3d &mcenter)
 Get a symbolic 'center' of the object. More...
 
virtual void Setup ()
 This might recompute the number of coordinates, DOFs, constraints, in case this might change (ex in ChAssembly), as well as state offsets of contained items (ex in ChMesh)
 
virtual void ForceToRest ()
 Set zero speed (and zero accelerations) in state, without changing the position. More...
 
virtual unsigned int GetNumCoordsPosLevel ()
 Get the number of coordinates at the position level. More...
 
virtual unsigned int GetNumCoordsVelLevel ()
 Get the number of coordinates at the velocity level. More...
 
virtual unsigned int GetNumConstraints ()
 Get the number of scalar constraints.
 
virtual unsigned int GetNumConstraintsUnilateral ()
 Get the number of unilateral scalar constraints.
 
unsigned int GetOffset_x ()
 Get offset in the state vector (position part)
 
unsigned int GetOffset_w ()
 Get offset in the state vector (speed part)
 
unsigned int GetOffset_L ()
 Get offset in the lagrangian multipliers.
 
void SetOffset_x (const unsigned int moff)
 Set offset in the state vector (position part) Note: only the ChSystem::Setup function should use this.
 
void SetOffset_w (const unsigned int moff)
 Set offset in the state vector (speed part) Note: only the ChSystem::Setup function should use this.
 
void SetOffset_L (const unsigned int moff)
 Set offset in the lagrangian multipliers Note: only the ChSystem::Setup function should use this.
 
virtual void IntStateGather (const unsigned int off_x, ChState &x, const unsigned int off_v, ChStateDelta &v, double &T)
 From item's state to global state vectors y={x,v} pasting the states at the specified offsets. More...
 
virtual void IntStateScatter (const unsigned int off_x, const ChState &x, const unsigned int off_v, const ChStateDelta &v, const double T, bool full_update)
 From global state vectors y={x,v} to item's state (and update) fetching the states at the specified offsets. More...
 
virtual void IntStateGatherAcceleration (const unsigned int off_a, ChStateDelta &a)
 From item's state acceleration to global acceleration vector. More...
 
virtual void IntStateScatterAcceleration (const unsigned int off_a, const ChStateDelta &a)
 From global acceleration vector to item's state acceleration. More...
 
virtual void IntStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv)
 Computes x_new = x + Dt , using vectors at specified offsets. More...
 
virtual void IntStateGetIncrement (const unsigned int off_x, const ChState &x_new, const ChState &x, const unsigned int off_v, ChStateDelta &Dv)
 Computes Dt = x_new - x, using vectors at specified offsets. More...
 
virtual void IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c)
 Takes the F force term, scale and adds to R at given offset: R += c*F. More...
 
virtual void IntLoadResidual_Mv (const unsigned int off, ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c)
 Takes the M*v term, multiplying mass by a vector, scale and adds to R at given offset: R += c*M*w. More...
 
virtual void IntLoadLumpedMass_Md (const unsigned int off, ChVectorDynamic<> &Md, double &err, const double c)
 Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More...
 
virtual void IntLoadConstraint_Ct (const unsigned int off, ChVectorDynamic<> &Qc, const double c)
 Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct. More...
 
virtual void InjectVariables (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChVariable objects associated with this item.
 
virtual void InjectKRMMatrices (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChKRMBlock objects associated with this item.
 
virtual void LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor)
 Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...
 
virtual void VariablesFbReset ()
 Sets the 'fb' part (the known term) of the encapsulated ChVariables to zero.
 
virtual void VariablesFbLoadForces (double factor=1)
 Adds the current forces (applied to item) into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor.
 
virtual void VariablesQbLoadSpeed ()
 Initialize the 'qb' part of the ChVariables with the current value of speeds. More...
 
virtual void VariablesFbIncrementMq ()
 Adds M*q (masses multiplied current 'qb') to Fb, ex. More...
 
virtual void VariablesQbSetSpeed (double step=0)
 Fetches the item speed (ex. More...
 
virtual void VariablesQbIncrementPosition (double step)
 Increment item positions by the 'qb' part of the ChVariables, multiplied by a 'step' factor. More...
 
virtual void ConstraintsBiLoad_Ct (double factor=1)
 Adds the current Ct (partial t-derivative, as in C_dt=0-> [Cq]*q_dt=-Ct) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_Qc (double factor=1)
 Adds the current Qc (the vector of C_dtdt=0 -> [Cq]*q_dtdt=Qc ) to the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsFbLoadForces (double factor=1)
 Adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints.
 
- Public Member Functions inherited from chrono::ChObj
 ChObj (const ChObj &other)
 
int GetIdentifier () const
 Get the unique integer identifier of this object. More...
 
void SetTag (int tag)
 Set an object integer tag (default: -1). More...
 
int GetTag () const
 Get the tag of this object.
 
void SetName (const std::string &myname)
 Set the name of this object.
 
std::string GetName () const
 Get the name of this object.
 
double GetChTime () const
 Gets the simulation time of this object.
 
void SetChTime (double m_time)
 Sets the simulation time of this object.
 
virtual std::string & ArchiveContainerName ()
 

Additional Inherited Members

- Protected Member Functions inherited from chrono::ChObj
int GenerateUniqueIdentifier ()
 
- Protected Attributes inherited from chrono::ChPhysicsItem
ChSystemsystem
 parent system
 
std::shared_ptr< ChVisualModelInstancevis_model_instance
 instantiated visualization model
 
std::vector< std::shared_ptr< ChCamera > > cameras
 set of cameras
 
unsigned int offset_x
 offset in vector of state (position part)
 
unsigned int offset_w
 offset in vector of state (speed part)
 
unsigned int offset_L
 offset in vector of lagrangian multipliers
 
- Protected Attributes inherited from chrono::ChObj
double ChTime
 object simulation time
 
std::string m_name
 object name
 
int m_identifier
 object unique identifier
 
int m_tag
 user-supplied tag
 

Member Function Documentation

◆ ArchiveIn()

void chrono::ChLinkRevoluteSpherical::ArchiveIn ( ChArchiveIn archive_in)
overridevirtual

Method to allow deserialization of transient data from archives.

Method to allow de serialization of transient data from archives.

Reimplemented from chrono::ChLink.

◆ GetFrame1Rel()

ChFrame chrono::ChLinkRevoluteSpherical::GetFrame1Rel ( ) const
overridevirtual

Get the link frame 1, relative to body 1.

This frame, defined on body 1 (the revolute side), is centered at the revolute joint location, has its X axis along the joint connector, and its Z axis aligned with the revolute axis.

Implements chrono::ChLink.

◆ GetFrame2Rel()

ChFrame chrono::ChLinkRevoluteSpherical::GetFrame2Rel ( ) const
overridevirtual

Get the link frame 2, relative to body 2.

This frame, defined on body 2 (the spherical side), is centered at the spherical joint location, has its X axis along the joint connector, and its Z axis aligned with the revolute axis.

Implements chrono::ChLink.

◆ Initialize() [1/2]

void chrono::ChLinkRevoluteSpherical::Initialize ( std::shared_ptr< ChBody body1,
std::shared_ptr< ChBody body2,
bool  local,
const ChVector3d pos1,
const ChVector3d dir1,
const ChVector3d pos2,
bool  auto_distance = true,
double  distance = 0 
)

Initialize this joint by specifying the two bodies to be connected, a point and a direction on body1 defining the revolute joint, and a point on the second body defining the spherical joint.

If local = true, it is assumed that these quantities are specified in the local body frames. Otherwise, it is assumed that they are specified in the absolute frame. The imposed distance between the two points can be either inferred from the provided configuration (auto_distance = true) or specified explicitly.

Parameters
body1first frame (revolute side)
body2second frame (spherical side)
localtrue if data given in body local frames
pos1point on first frame (center of revolute)
dir1direction of revolute on first frame
pos2point on second frame (center of spherical)
auto_distancetrue if imposed distance equal to |pos1 - po2|
distanceimposed distance (used only if auto_distance = false)

◆ Initialize() [2/2]

void chrono::ChLinkRevoluteSpherical::Initialize ( std::shared_ptr< ChBody body1,
std::shared_ptr< ChBody body2,
const ChCoordsys<> &  csys,
double  distance 
)

Initialize this joint by specifying the two bodies to be connected, a coordinate system specified in the absolute frame, and the distance of the massless connector.

The composite joint is constructed such that the direction of the revolute joint is aligned with the Z axis of the specified coordinate system and the spherical joint is at the specified distance along the X axis.

Parameters
body1first frame (revolute side)
body2second frame (spherical side)
csysjoint coordinate system (in absolute frame)
distanceimposed distance

◆ Update()

void chrono::ChLinkRevoluteSpherical::Update ( double  time,
bool  update_assets = true 
)
overridevirtual

Perform the update of this joint at the specified time: compute jacobians, constraint violations, etc.

and cache in internal structures

Reimplemented from chrono::ChLink.


The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono/physics/ChLinkRevoluteSpherical.h
  • /builds/uwsbel/chrono/src/chrono/physics/ChLinkRevoluteSpherical.cpp