Description

Class for links which connect two 'markers'.

The markers are two ChMarker objects each belonging to the two linked ChBody parts. Many specialized classes are based on this ChLinkMarkers class, for example the family of ChLinkLock classes. ChLinkMarkers class allows an optional force vector and torque vector to be set between the two connected markers.

#include <ChLinkMarkers.h>

Inheritance diagram for chrono::ChLinkMarkers:
Collaboration diagram for chrono::ChLinkMarkers:

Public Member Functions

virtual ChLinkMarkersClone () const override
 "Virtual" copy constructor (covariant return type).
 
ChMarkerGetMarker1 () const
 Return the 1st referenced marker (the secondary marker, on 1st body).
 
ChMarkerGetMarker2 () const
 Return the 2nd referenced marker (the main marker, on 2nd body).
 
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...
 
const ChCoordsysdGetRelCoordsys () const
 Relative position of marker 1 respect to marker 2.
 
const ChCoordsysdGetRelCoordsysDt () const
 Relative speed of marker 1 respect to marker 2.
 
const ChCoordsysdGetRelCoordsysDt2 () const
 Relative acceleration of marker 1 respect to marker 2.
 
double GetRelAngle () const
 Relative rotation angle of marker 1 respect to marker 2.
 
const ChVector3dGetRelAxis () const
 Relative finite rotation axis of marker 1 respect to marker 2.
 
const ChVector3dGetRelAngleAxis () const
 
const ChVector3dGetRelativeAngVel () const
 Relative angular speed of marker 1 respect to marker 2.
 
const ChVector3dGetRelativeAngAcc () const
 Relative angular acceleration of marker 1 respect to marker 2.
 
double GetDistance () const
 Relative 'polar' distance of marker 1 respect to marker 2.
 
double GetDistanceDt () const
 Relative speed of marker 1 respect to marker 2, along the polar distance vector.
 
const ChVector3dGetAccumulatedForce () const
 Get the total applied force accumulators (force, momentum) in link coords. More...
 
const ChVector3dGetAccumulatedTorque () const
 
virtual void SetupMarkers (ChMarker *mark1, ChMarker *mark2)
 Set the two markers associated with this link.
 
virtual void Initialize (std::shared_ptr< ChMarker > mark1, std::shared_ptr< ChMarker > mark2)
 Initialize the link to join two markers. More...
 
virtual void Initialize (std::shared_ptr< ChBody > mbody1, std::shared_ptr< ChBody > mbody2, const ChFrame<> &frame)
 Initialize the link to join two rigid bodies. More...
 
virtual void Initialize (std::shared_ptr< ChBody > mbody1, std::shared_ptr< ChBody > mbody2, bool rel_frames, const ChFrame<> &frame1, const ChFrame<> &frame2)
 Initialize the link to join two rigid bodies. More...
 
virtual ChFrame GetVisualModelFrame (unsigned int nclone=0) const override
 Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More...
 
virtual void UpdateRelMarkerCoords ()
 Updates auxiliary quantities for all relative degrees of freedom of the two markers.
 
virtual void UpdateForces (double mytime)
 Updates auxiliary forces caused by springs/dampers/etc. More...
 
virtual void Update (double mytime, bool update_assets=true) override
 Complete link update: UpdateTime -> UpdateRelMarkerCoords -> UpdateForces.
 
virtual void IntLoadResidual_F (const unsigned int off, ChVectorDynamic<> &R, const double c) override
 Adds force to residual R, as R*= F*c NOTE: here the off offset in R is NOT used because add F at the TWO offsets of the two connected bodies, so it is assumed that offsets for Body1 and Body2 variables have been already set properly!
 
virtual void ConstraintsFbLoadForces (double factor=1) override
 Overrides the empty behaviour of the parent ChLink implementation, which does not consider any user-imposed force between the two bodies. 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 GetNumConstraintsBilateral ()
 Get the number of bilateral 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 IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L)
 From item's reaction forces to global reaction vector. More...
 
virtual void IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L)
 From global reaction vector to item's reaction forces. 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_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 IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c)
 Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L. More...
 
virtual void IntLoadConstraint_C (const unsigned int off, ChVectorDynamic<> &Qc, const double c, bool do_clamp, double recovery_clamp)
 Takes the term C, scale and adds to Qc at given offset: Qc += c*C. 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 IntToDescriptor (const unsigned int off_v, const ChStateDelta &v, const ChVectorDynamic<> &R, const unsigned int off_L, const ChVectorDynamic<> &L, const ChVectorDynamic<> &Qc)
 Prepare variables and constraints to accommodate a solution: More...
 
virtual void IntFromDescriptor (const unsigned int off_v, ChStateDelta &v, const unsigned int off_L, ChVectorDynamic<> &L)
 After a solver solution, fetch values from variables and constraints into vectors: More...
 
virtual void InjectVariables (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChVariable objects associated with this item.
 
virtual void InjectConstraints (ChSystemDescriptor &descriptor)
 Register with the given system descriptor any ChConstraint objects associated with this item.
 
virtual void LoadConstraintJacobians ()
 Compute and load current Jacobians in encapsulated ChConstraint objects.
 
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 ConstraintsBiReset ()
 Sets to zero the known term (b_i) of encapsulated ChConstraints.
 
virtual void ConstraintsBiLoad_C (double factor=1, double recovery_clamp=0.1, bool do_clamp=false)
 Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.
 
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 ConstraintsFetch_react (double factor=1)
 Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...
 
- 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.
 
const 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 ()
 

Protected Member Functions

 ChLinkMarkers (const ChLinkMarkers &other)
 
- Protected Member Functions inherited from chrono::ChObj
int GenerateUniqueIdentifier ()
 

Protected Attributes

ChMarkermarker1
 secondary coordsys
 
ChMarkermarker2
 main coordsys
 
ChCoordsysd relM
 relative marker position 2-1
 
ChCoordsysd relM_dt
 relative marker speed
 
ChCoordsysd relM_dtdt
 relative marker acceleration
 
double relAngle
 relative angle of rotation
 
ChVector3d relAxis
 relative axis of rotation
 
ChVector3d relRotaxis
 relative rotaion vector =angle*axis
 
ChVector3d relWvel
 relative angular speed
 
ChVector3d relWacc
 relative angular acceleration
 
double dist
 the distance between the two origins of markers,
 
double dist_dt
 the speed between the two origins of markers
 
ChVector3d C_force
 internal force applied by springs/dampers/actuators
 
ChVector3d C_torque
 internal torque applied by springs/dampers/actuators
 
ChVector3d PQw
 
ChVector3d PQw_dt
 
ChVector3d PQw_dtdt
 
ChQuaternion q_AD
 
ChQuaternion q_BC
 
ChQuaternion q_8
 
ChVector3d q_4
 
- 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::ChLinkMarkers::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.

Reimplemented in chrono::ChLinkLockLock, chrono::ChLinkLock, chrono::ChLinkLockGear, chrono::ChLinkLockPulley, chrono::ChLinkLockTrajectory, chrono::ChLinkLockClearance, chrono::ChLinkLockBrake, chrono::ChLinkBushing, chrono::ChLinkLockLinActuator, chrono::ChLinkLockPointSpline, and chrono::ChLinkLockScrew.

◆ ConstraintsFbLoadForces()

void chrono::ChLinkMarkers::ConstraintsFbLoadForces ( double  factor = 1)
overridevirtual

Overrides the empty behaviour of the parent ChLink implementation, which does not consider any user-imposed force between the two bodies.

It adds the current link-forces, if any, (caused by springs, etc.) to the 'fb' vectors of the ChVariables referenced by encapsulated ChConstraints. In details, it adds the effect caused by C_force and C_torque. Both C_force and C_torque these forces are considered expressed in the reference coordsystem of marker2 (the MAIN marker), and their application point is the origin of marker1 (the SLAVE marker).

Reimplemented from chrono::ChPhysicsItem.

◆ GetAccumulatedForce()

const ChVector3d& chrono::ChLinkMarkers::GetAccumulatedForce ( ) const
inline

Get the total applied force accumulators (force, momentum) in link coords.

These forces might be affected by additional springs, dampers, etc. but they do not include the reaction forces.

◆ GetFrame1Rel()

virtual ChFrame chrono::ChLinkMarkers::GetFrame1Rel ( ) const
inlineoverridevirtual

Get the link frame 1, relative to body 1.

For this class link frame 1 is actually marker 1.

Implements chrono::ChLink.

◆ GetFrame2Rel()

virtual ChFrame chrono::ChLinkMarkers::GetFrame2Rel ( ) const
inlineoverridevirtual

Get the link frame 2, relative to body 2.

For this class link frame 2 is actually marker 2.

Implements chrono::ChLink.

◆ GetVisualModelFrame()

virtual ChFrame chrono::ChLinkMarkers::GetVisualModelFrame ( unsigned int  nclone = 0) const
inlineoverridevirtual

Get the reference frame (expressed in and relative to the absolute frame) of the visual model.

For a ChLinkMarkers, this returns the absolute coordinate system of the main marker2.

Reimplemented from chrono::ChLinkBase.

◆ Initialize() [1/3]

void chrono::ChLinkMarkers::Initialize ( std::shared_ptr< ChBody mbody1,
std::shared_ptr< ChBody mbody2,
bool  rel_frames,
const ChFrame<> &  frame1,
const ChFrame<> &  frame2 
)
virtual

Initialize the link to join two rigid bodies.

This version uses the local positions and alignments on the two bodies. Both rigid bodies must belong to the same system. Two markers will be created and added to the rigid bodies.

Parameters
mbody1first body to join
mbody2second body to join
rel_framesmarker frames are relative (true) or absolute (false)
frame1position & alignment of 1st marker (absolute or relative to body1)
frame2position & alignment of 2nd marker (absolute or relative to body2)

◆ Initialize() [2/3]

void chrono::ChLinkMarkers::Initialize ( std::shared_ptr< ChBody mbody1,
std::shared_ptr< ChBody mbody2,
const ChFrame<> &  frame 
)
virtual

Initialize the link to join two rigid bodies.

Both rigid bodies must belong to the same system. This version creates the link at the specified absolute position and alignment. Two markers will be created and added to the rigid bodies.

Parameters
mbody1first body to join
mbody2second body to join
frameinitial absolute position & alignment

◆ Initialize() [3/3]

void chrono::ChLinkMarkers::Initialize ( std::shared_ptr< ChMarker mark1,
std::shared_ptr< ChMarker mark2 
)
virtual

Initialize the link to join two markers.

Each marker must belong to a rigid body, and both rigid bodies must belong to the same system. The position of mark2 is used as link's position and main reference.

Parameters
mark1first marker to join (secondary)
mark2second marker to join (main)

◆ UpdateForces()

void chrono::ChLinkMarkers::UpdateForces ( double  mytime)
virtual

Updates auxiliary forces caused by springs/dampers/etc.

which may be connected between the two link bodies. These forces are considered in the reference coordsystem of marker2 (the main marker), and their application point is the origin of marker1 (the secondary marker).

Reimplemented in chrono::ChLinkLock, chrono::ChLinkLockClearance, and chrono::ChLinkLockBrake.


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