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:

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Collaboration diagram for chrono::ChLinkMarkers:

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Public Member Functions
virtual ChLinkMarkers *	Clone () const override
	"Virtual" copy constructor (covariant return type).

ChMarker *	GetMarker1 () const
	Return the 1st referenced marker (the secondary marker, on 1st body).

ChMarker *	GetMarker2 () 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 ChCoordsysd &	GetRelCoordsys () const
	Relative position of marker 1 respect to marker 2.

const ChCoordsysd &	GetRelCoordsysDt () const
	Relative speed of marker 1 respect to marker 2.

const ChCoordsysd &	GetRelCoordsysDt2 () const
	Relative acceleration of marker 1 respect to marker 2.

double	GetRelAngle () const
	Relative rotation angle of marker 1 respect to marker 2.

const ChVector3d &	GetRelAxis () const
	Relative finite rotation axis of marker 1 respect to marker 2.

const ChVector3d &	GetRelAngleAxis () const

const ChVector3d &	GetRelativeAngVel () const
	Relative angular speed of marker 1 respect to marker 2.

const ChVector3d &	GetRelativeAngAcc () 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 ChVector3d &	GetAccumulatedForce () const
	Get the total applied force accumulators (force, momentum) in link coords. More...

const ChVector3d &	GetAccumulatedTorque () 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= Fc 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::ChLink
	ChLink (const ChLink &other)

virtual unsigned int	GetNumAffectedCoords () override
	Get the number of scalar variables affected by constraints in this link.

ChBodyFrame *	GetBody1 () const
	Get the constrained body 1.

ChBodyFrame *	GetBody2 () const
	Get the constrained body 2.

virtual ChFramed	GetFrame1Abs () const override
	Get the link frame 1, on body 1, expressed in the absolute frame.

virtual ChFramed	GetFrame2Abs () const override
	Get the link frame 2, on body 2, expressed in the absolute frame.

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 object, expressed in the link frame 2.

virtual void	UpdateTime (double mytime)
	Given new time, current body state, update time-dependent quantities in link state, for example motion laws, moving markers, etc. More...

virtual void	Update (bool update_assets=true) override
	As above, but with current time.

virtual void	UpdatedExternalTime (double prevtime, double time)
	Called from a external package (i.e. a plugin, a CAD app.) to report that time has changed.

Public Member Functions inherited from chrono::ChLinkBase
	ChLinkBase (const ChLinkBase &other)

bool	IsValid ()
	Tells if the link data is currently valid. More...

void	SetValid (bool mon)
	Set the status of link validity.

bool	IsDisabled ()
	Tells if all constraints of this link are currently turned on or off by the user.

virtual void	SetDisabled (bool mdis)
	User can use this to enable/disable all the constraint of the link as desired.

bool	IsBroken ()
	Tells if the link is broken, for excess of pulling/pushing.

virtual void	SetBroken (bool mon)
	Set the 'broken' status vof this link.

virtual bool	IsActive () const override
	Return true if the link is currently active and thereofre included into the system solver. More...

virtual ChVectorDynamic	GetConstraintViolation () const
	Get the current constraint violations.

virtual bool	IsRequiringWaking ()
	Tells if this link requires that the connected ChBody objects must be waken if they are sleeping. More...

Public Member Functions inherited from chrono::ChPhysicsItem
	ChPhysicsItem (const ChPhysicsItem &other)

ChSystem *	GetSystem () 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< ChVisualModel >	GetVisualModel () 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< ChVisualShape >	GetVisualShape (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< ChVisualShapeFEA >	GetVisualShapeFEA (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 Mv term, multiplying mass by a vector, scale and adds to R at given offset: R += cM*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 += cCq'*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
ChMarker *	marker1
	secondary coordsys

ChMarker *	marker2
	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::ChLink
ChBodyFrame *	m_body1
	first connected body

ChBodyFrame *	m_body2
	second connected body

ChVector3d	react_force
	xyz reactions, expressed in local coordinate system of link;

ChVector3d	react_torque
	torque reactions, expressed in local coordinate system of link;

Protected Attributes inherited from chrono::ChLinkBase
bool	disabled
	all constraints of link disabled because of user needs

bool	valid
	link data is valid

bool	broken
	link is broken because of excessive pulling/pushing.

Protected Attributes inherited from chrono::ChPhysicsItem
ChSystem *	system
	parent system

std::shared_ptr< ChVisualModelInstance >	vis_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

mbody1	first body to join
mbody2	second body to join
rel_frames	marker frames are relative (true) or absolute (false)
frame1	position & alignment of 1st marker (absolute or relative to body1)
frame2	position & 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

mbody1	first body to join
mbody2	second body to join
frame	initial 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

mark1	first marker to join (secondary)
mark2	second 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

Description

Public Member Functions

Protected Member Functions

Protected Attributes

Member Function Documentation

◆ ArchiveIn()

◆ ConstraintsFbLoadForces()

◆ GetAccumulatedForce()

◆ GetFrame1Rel()

◆ GetFrame2Rel()

◆ GetVisualModelFrame()

◆ Initialize() [1/3]

◆ Initialize() [2/3]

◆ Initialize() [3/3]

◆ UpdateForces()