Description

Base class for joints implemented using the "lock" formulation.

This implementation of joints allow the constrained frame (ChMarker) to move with respect to the constrained body. Moreover, a ChLinkLock joint can:

limit the range of motion of those unconstrained degrees of freedom by means of ChLinkLimit objects.
impose a relative force or a torque on the constrained marker by means of ChLinkForce objects.

#include <ChLinkLock.h>

Inheritance diagram for chrono::ChLinkLock:

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Collaboration diagram for chrono::ChLinkLock:

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Public Types
using	ChConstraintVectorX = Eigen::Matrix< double, Eigen::Dynamic, 1, Eigen::ColMajor, 7, 1 >

using	ChConstraintMatrixX6 = Eigen::Matrix< double, Eigen::Dynamic, BODY_DOF, Eigen::RowMajor, 7, BODY_DOF >

using	ChConstraintMatrixX7 = Eigen::Matrix< double, Eigen::Dynamic, BODY_QDOF, Eigen::RowMajor, 7, BODY_QDOF >

Public Member Functions
	ChLinkLock ()
	Default constructor. Builds a ChLinkLockSpherical.

	ChLinkLock (const ChLinkLock &other)
	Copy constructor.

virtual ChLinkLock *	Clone () const override
	"Virtual" copy constructor (covariant return type).

virtual void	SetDisabled (bool mdis) override
	Enable/disable all constraints of the link.

virtual void	SetBroken (bool mon) override
	For example, a 3rd party software can set the 'broken' status via this method.

ChLinkMask &	GetMask ()
	Get the link mask (a container for the ChConstraint items).

virtual void	SetupMarkers (ChMarker mark1, ChMarker mark2) override
	Set the two markers associated with this link.

ChLinkForce &	ForceX ()
	Accessors for internal forces on free degrees of freedom. More...

ChLinkForce &	ForceY ()

ChLinkForce &	ForceZ ()

ChLinkForce &	ForceRx ()

ChLinkForce &	ForceRy ()

ChLinkForce &	ForceRz ()

ChLinkForce &	ForceD ()

ChLinkForce &	ForceRp ()

ChLinkLimit &	LimitX ()
	Accessors for limits on free degrees of freedom. More...

ChLinkLimit &	LimitY ()

ChLinkLimit &	LimitZ ()

ChLinkLimit &	LimitRx ()

ChLinkLimit &	LimitRy ()

ChLinkLimit &	LimitRz ()

ChLinkLimit &	LimitD ()

ChLinkLimit &	LimitRp ()

virtual unsigned int	GetNumConstraints () override
	Get the number of scalar constraints for this link.

virtual unsigned int	GetNumConstraintsBilateral () override
	Get the number of bilateral constraints for this link.

virtual unsigned int	GetNumConstraintsUnilateral () override
	Get the number of unilateral constraints for this link.

virtual ChVectorDynamic	GetConstraintViolation () const override
	Link violation (residuals of the link constraint equations).

const ChConstraintVectorX &	GetConstraintViolationDt () const
	Time derivatives of link violation.

const ChConstraintVectorX &	GetConstraintViolationDt2 () const
	Second time derivatives of link violation.

const ChConstraintMatrixX7 &	GetCq1 () const
	The jacobian (body n.1 part, i.e. columns= 7 , rows= m_num_constr)

const ChConstraintMatrixX7 &	GetCq2 () const
	The jacobian (body n.2 part, i.e. columns= 7 , rows= m_num_constr)

const ChConstraintMatrixX6 &	GetCqw1 () const
	The jacobian for Wl (col 6, rows= m_num_constr), as [Cqw1_rot]=[Cq_rot]*[Gl_1]'.

const ChConstraintMatrixX6 &	GetCqw2 () const
	The jacobian for Wl (col 6, rows= m_num_constr) as [Cqw2_rot]=[Cq_rot]*[Gl_2]'.

const ChConstraintVectorX &	GetQc () const
	The gamma vector used in dynamics, [Cq]x''=Qc.

const ChConstraintVectorX &	GetCt () const
	The Ct vector used in kinematics, [Cq]x'=Ct.

const ChConstraintVectorX &	GetReact () const
	Access the reaction vector, after dynamics computations.

virtual void	UpdateState ()
	Given current time and body state, computes the constraint differentiation to get the the state matrices Cq1, Cq2, Qc, Ct , and also C, C_dt, C_dtd.

virtual void	UpdateForces (double mytime) override
	Updates the local F, M forces adding penalties from ChLinkLimit objects, if any.

void	UpdateCqw ()
	Updates Cqw1 and Cqw2 given updated Cq1 and Cq2, i.e. More...

virtual void	Update (double mytime, bool update_assets=true) override
	Full update. 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.

Public Member Functions inherited from chrono::ChLinkMarkers
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	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	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...

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.

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

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

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 () const
	Get the axis-aligned bounding box (AABB) of this object. More...

virtual ChVector3d	GetCenter () const
	Get a symbolic 'center' of the object. More...

virtual void	Setup ()
	Perform setup operations. More...

void	UpdateVisualModel ()
	Utility function to update only the associated visual assets (if any).

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...

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_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	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...

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 Types
enum	Type { LOCK, SPHERICAL, POINTPLANE, POINTLINE, CYLINDRICAL, PRISMATIC, PLANEPLANE, OLDHAM, REVOLUTE, FREE, ALIGN, PARALLEL, PERPEND, TRAJECTORY, CLEARANCE, REVOLUTEPRISMATIC }
	Type of link-lock.

Protected Member Functions
void	BuildLink ()
	Resize matrices and initializes all mask-dependent quantities. More...

void	BuildLinkType (Type link_type)
	Set the mask and then resize matrices.

void	BuildLink (bool x, bool y, bool z, bool e0, bool e1, bool e2, bool e3)

void	ChangeType (Type new_link_type)

virtual void	IntStateScatterReactions (const unsigned int off_L, const ChVectorDynamic<> &L) override
	From global reaction vector to item's reaction forces. More...

virtual void	IntStateGatherReactions (const unsigned int off_L, ChVectorDynamic<> &L) override
	From item's reaction forces to global reaction vector. More...

virtual void	IntLoadResidual_CqL (const unsigned int off_L, ChVectorDynamic<> &R, const ChVectorDynamic<> &L, const double c) override
	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) override
	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) override
	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) override
	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) override
	After a solver solution, fetch values from variables and constraints into vectors: More...

virtual void	InjectConstraints (ChSystemDescriptor &descriptor) override
	Register with the given system descriptor any ChConstraint objects associated with this item.

virtual void	ConstraintsBiReset () override
	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) override
	Adds the current C (constraint violation) to the known term (b_i) of encapsulated ChConstraints.

virtual void	ConstraintsBiLoad_Ct (double factor=1) override
	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) override
	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	LoadConstraintJacobians () override
	Compute and load current Jacobians in encapsulated ChConstraint objects.

virtual void	ConstraintsFetch_react (double factor=1) override
	Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints. More...

Protected Member Functions inherited from chrono::ChLinkMarkers
	ChLinkMarkers (const ChLinkMarkers &other)

Protected Member Functions inherited from chrono::ChObj
int	GenerateUniqueIdentifier ()

Protected Attributes
Type	type
	type of link_lock joint

ChLinkMaskLF	mask
	scalar constraints

int	m_num_constr
	number of degrees of constraint

int	m_num_constr_bil
	number of degrees of constraint (bilateral constraintss)

int	m_num_constr_uni
	number of degrees of constraint (unilateral constraints, excluding joint limits)

std::unique_ptr< ChLinkForce >	force_D
	the force acting on the straight line m1-m2 (distance)

std::unique_ptr< ChLinkForce >	force_R
	the torque acting about rotation axis

std::unique_ptr< ChLinkForce >	force_X
	the force acting along X dof

std::unique_ptr< ChLinkForce >	force_Y
	the force acting along Y dof

std::unique_ptr< ChLinkForce >	force_Z
	the force acting along Z dof

std::unique_ptr< ChLinkForce >	force_Rx
	the torque acting about Rx dof

std::unique_ptr< ChLinkForce >	force_Ry
	the torque acting about Ry dof

std::unique_ptr< ChLinkForce >	force_Rz
	the torque acting about Rz dof

double	d_restlength
	the rest length of the "d_spring" spring

std::unique_ptr< ChLinkLimit >	limit_X
	the upper/lower limits for X dof

std::unique_ptr< ChLinkLimit >	limit_Y
	the upper/lower limits for Y dof

std::unique_ptr< ChLinkLimit >	limit_Z
	the upper/lower limits for Z dof

std::unique_ptr< ChLinkLimit >	limit_Rx
	the upper/lower limits for Rx dof

std::unique_ptr< ChLinkLimit >	limit_Ry
	the upper/lower limits for Ry dof

std::unique_ptr< ChLinkLimit >	limit_Rz
	the upper/lower limits for Rz dof

std::unique_ptr< ChLinkLimit >	limit_Rp
	the polar (conical) limit for "shoulder"rotation

std::unique_ptr< ChLinkLimit >	limit_D
	the polar (conical) limit for "shoulder"rotation

ChConstraintVectorX	C
	C(q,q_dt,t), the constraint violations.

ChConstraintVectorX	C_dt
	Speed constraint violations.

ChConstraintVectorX	C_dtdt
	Acceleration constraint violations.

ChConstraintMatrixX7	Cq1
	[Cq1], the jacobian of the constraint, for coords1, [m_num_constr,7]

ChConstraintMatrixX7	Cq2
	[Cq2], the jacobian of the constraint, for coords2. [m_num_constr,7]

ChConstraintMatrixX6	Cqw1
	Jacobian [m_num_constr,6] for 3 Wl rot.coordinates instead of quaternions.

ChConstraintMatrixX6	Cqw2
	Jacobian [m_num_constr,6] for 3 Wl rot.coordinates instead of quaternions.

ChConstraintVectorX	Qc
	{Qc}, the known part, {Qc}=-{C_dtdt}-([Cq]{q_dt})q-2[Cq_dt]{q_dt}

ChConstraintVectorX	Ct
	partial derivative of the link kin. equation wrt to time

ChConstraintVectorX	react
	{l}, the lagrangians forces in the constraints

ChMatrixNM< double, 7, BODY_QDOF >	Cq1_temp

ChMatrixNM< double, 7, BODY_QDOF >	Cq2_temp

ChVectorN< double, 7 >	Qc_temp

ChCoordsysd	Ct_temp

Protected Attributes inherited from chrono::ChLinkMarkers
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

Friends
class	ChConveyor

Member Function Documentation

◆ BuildLink()

void chrono::ChLinkLock::BuildLink ( )

protected

Resize matrices and initializes all mask-dependent quantities.

Sets number of constraints based on current mask information.

◆ ConstraintsFetch_react()

void chrono::ChLinkLock::ConstraintsFetch_react ( double factor = 1 )

overrideprotectedvirtual

Fetches the reactions from the lagrangian multiplier (l_i) of encapsulated ChConstraints.

Mostly used after the solver provided the solution in ChConstraints. Also, should convert the reactions obtained from dynamical simulation, from link space to intuitive react_force and react_torque.

Reimplemented from chrono::ChPhysicsItem.

◆ ForceX()

ChLinkForce & chrono::ChLinkLock::ForceX ( )

Accessors for internal forces on free degrees of freedom.

These functions provide access to initialize and set parameters for link forces acting on different degrees of freedom of the joint. Note that they use "lazy initialization"; an internal link force object is created on the first invocation of the corresponding accessor function.

◆ IntFromDescriptor()

void chrono::ChLinkLock::IntFromDescriptor	(	const unsigned int	off_v,
		ChStateDelta &	v,
		const unsigned int	off_L,
		ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

After a solver solution, fetch values from variables and constraints into vectors:

Parameters

off_v	offset for v
v	vector to where the q 'unknowns' term of the variables will be copied
off_L	offset for L
L	vector to where L 'lagrangian ' term of the constraints will be copied

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_C()

void chrono::ChLinkLock::IntLoadConstraint_C	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c,
		bool	do_clamp,
		double	recovery_clamp
	)

overrideprotectedvirtual

Takes the term C, scale and adds to Qc at given offset: Qc += c*C.

Parameters

off	offset in Qc residual
Qc	result: the Qc residual, Qc += c*C
c	a scaling factor
do_clamp	apply clamping to c*C?
recovery_clamp	value for min/max clamping of c*C

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadConstraint_Ct()

void chrono::ChLinkLock::IntLoadConstraint_Ct	(	const unsigned int	off,
		ChVectorDynamic<> &	Qc,
		const double	c
	)

overrideprotectedvirtual

Takes the term Ct, scale and adds to Qc at given offset: Qc += c*Ct.

Parameters

off	offset in Qc residual
Qc	result: the Qc residual, Qc += c*Ct
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntLoadResidual_CqL()

void chrono::ChLinkLock::IntLoadResidual_CqL	(	const unsigned int	off_L,
		ChVectorDynamic<> &	R,
		const ChVectorDynamic<> &	L,
		const double	c
	)

overrideprotectedvirtual

Takes the term Cq'*L, scale and adds to R at given offset: R += c*Cq'*L.

Parameters

off_L	offset in L multipliers
R	result: the R residual, R += cCq'L
L	the L vector
c	a scaling factor

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateGatherReactions()

void chrono::ChLinkLock::IntStateGatherReactions	(	const unsigned int	off_L,
		ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

From item's reaction forces to global reaction vector.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntStateScatterReactions()

void chrono::ChLinkLock::IntStateScatterReactions	(	const unsigned int	off_L,
		const ChVectorDynamic<> &	L
	)

overrideprotectedvirtual

From global reaction vector to item's reaction forces.

Parameters

off_L	offset in L vector
L	L vector of reaction forces

Reimplemented from chrono::ChPhysicsItem.

◆ IntToDescriptor()

void chrono::ChLinkLock::IntToDescriptor	(	const unsigned int	off_v,
		const ChStateDelta &	v,
		const ChVectorDynamic<> &	R,
		const unsigned int	off_L,
		const ChVectorDynamic<> &	L,
		const ChVectorDynamic<> &	Qc
	)

overrideprotectedvirtual

Prepare variables and constraints to accommodate a solution:

Parameters

off_v	offset for v and R
v	vector copied into the q 'unknowns' term of the variables
R	vector copied into the F 'force' term of the variables
off_L	offset for L and Qc
L	vector copied into the L 'lagrangian ' term of the constraints
Qc	vector copied into the Qb 'constraint' term of the constraints

Reimplemented from chrono::ChPhysicsItem.

◆ LimitX()

ChLinkLimit & chrono::ChLinkLock::LimitX ( )

Accessors for limits on free degrees of freedom.

These functions provide access to initialize and set parameters for link limits on different free degrees of freedom of the joint. Note that they use "lazy initialization"; an internal link limit object is created on the first invocation of the corresponding accessor function.

◆ Update()

void chrono::ChLinkLock::Update	(	double	mytime,
		bool	update_assets = `true`
	)

overridevirtual

Full update.

Fills-in all the matrices of the link, and does all required calculations by calling specific Update functions in sequence:

    UpdateTime;
    UpdateRelMarkerCoords;
    UpdateState;
    UpdateCqw
    UpdateForces;

Reimplemented from chrono::ChLinkMarkers.

◆ UpdateCqw()

void chrono::ChLinkLock::UpdateCqw ( )

Updates Cqw1 and Cqw2 given updated Cq1 and Cq2, i.e.

computes the jacobians with 'Wl' rotational coordinates knowing the jacobians for body rotations in quaternion coordinates.

The documentation for this class was generated from the following files:

/builds/uwsbel/chrono/src/chrono/physics/ChLinkLock.h
/builds/uwsbel/chrono/src/chrono/physics/ChLinkLock.cpp

Description

Public Types

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Friends

Member Function Documentation

◆ BuildLink()

◆ ConstraintsFetch_react()

◆ ForceX()

◆ IntFromDescriptor()

◆ IntLoadConstraint_C()

◆ IntLoadConstraint_Ct()

◆ IntLoadResidual_CqL()

◆ IntStateGatherReactions()

◆ IntStateScatterReactions()

◆ IntToDescriptor()

◆ LimitX()

◆ Update()

◆ UpdateCqw()