Description

Class for translational spring-damper-actuator (TSDA) with the force optionally specified through a functor object (default, linear TSDA).

Optionally, a ChLinkTSDA can have internal dynamics, described by a system of ODEs. The internal states are integrated simultaneous with the containing system and they can be accessed and used in the force calculation. ChLinkTSDA provides optional support for computing Jacobians of the generalized forces.

#include <ChLinkTSDA.h>

Inheritance diagram for chrono::ChLinkTSDA:

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Collaboration diagram for chrono::ChLinkTSDA:

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Classes
class	ForceFunctor
	Class to be used as a callback interface for calculating the general spring-damper force. More...

class	ODE
	Class to be used as a callback interface for specifying the ODE, y' = f(t,y); y(0) = y0. More...

Public Member Functions
	ChLinkTSDA (const ChLinkTSDA &other)

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

void	SetRestLength (double len)
	Set spring rest (free) length. More...

void	SetSpringCoefficient (double k)
	Set spring coefficient (default: 0). More...

void	SetDampingCoefficient (double r)
	Set damping coefficient (default: 0). More...

void	SetActuatorForce (double f)
	Set constant actuation force (default: 0). More...

void	IsStiff (bool val)
	Declare the forces generated by this spring as stiff (default: false). More...

const ChVectorDynamic &	GetStates () const
	Get current states.

double	GetRestLength () const
	Get the spring rest (free) length.

double	GetLength () const
	Get current length.

double	GetDeformation () const
	Get current deformation.

double	GetVelocity () const
	Get current length rate of change.

double	GetForce () const
	Get current force (in the direction of the force element).

const ChVector &	GetPoint1Rel () const
	Get the endpoint location on 1st body (expressed in body coordinate system)

const ChVector &	GetPoint1Abs () const
	Get the endpoint location on 1st body (expressed in absolute coordinate system)

const ChVector &	GetPoint2Rel () const
	Get the endpoint location on 2nd body (expressed in body coordinate system)

const ChVector &	GetPoint2Abs () const
	Get the endpoint location on 1st body (expressed in absolute coordinate system)

double	GetSpringCoefficient () const
	Get the value of the spring coefficient. More...

double	GetDampingCoefficient () const
	Get the value of the damping coefficient. More...

double	GetActuatorForce () const
	Get the constant acutation force. More...

void	RegisterForceFunctor (ForceFunctor *functor)
	Specify the functor object for calculating the force.

void	RegisterODE (ODE *functor)
	Specify the functor object for calculating the ODE right-hand side.

void	Initialize (std::shared_ptr< ChBody > body1, std::shared_ptr< ChBody > body2, bool pos_are_relative, ChVector<> loc1, ChVector<> loc2, bool auto_rest_length=true, double rest_length=0)
	Initialize the spring, specifying the two bodies to be connected, the location of the two anchor points of each body (each expressed in body or absolute coordinates), and the imposed rest length of the spring. More...

virtual void	ArchiveOUT (ChArchiveOut &marchive) override
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIN (ChArchiveIn &marchive) override
	Method to allow deserialization of transient data from archives.

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

int	GetLeftDOF ()
	Get the number of free degrees of freedom left by this link, between two bodies.

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

ChBodyFrame *	GetBody1 ()
	Get the constrained body '1', the 'slave' body.

ChBodyFrame *	GetBody2 ()
	Get the constrained body '2', the 'master' body.

virtual ChCoordsys	GetLinkRelativeCoords ()
	Get the link coordinate system, expressed relative to Body2 (the 'master' body). More...

virtual ChCoordsys	GetLinkAbsoluteCoords () override
	Get the link coordinate system in absolute reference. More...

virtual ChVector	Get_react_force () override
	Get reaction force, expressed in link coordinate system.

virtual ChVector	Get_react_torque () override
	Get reaction torque, expressed in link coordinate system.

virtual int	RestoreRedundant ()
	If some constraint is redundant, return to normal state //*OBSOLETE*.

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.

bool	IsActive ()
	An important function! Tells if the link is currently active, in general, that is tells if it must be included into the system solver or not. More...

virtual ChFrame	GetAssetsFrame (unsigned int nclone=0) override
	Get the master coordinate system for the assets, in absolute reference. 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() and also add to new collision system / remove from old coll.system.

void	AddAsset (std::shared_ptr< ChAsset > masset)
	Add an optional asset (it can be used to define visualization shapes, es ChSphereShape, or textures, or custom attached properties that the user can define by creating his class inherited from ChAsset)

std::vector< std::shared_ptr< ChAsset > > &	GetAssets ()
	Access to the list of optional assets.

std::shared_ptr< ChAsset >	GetAssetN (unsigned int num)
	Access the Nth asset in the list of optional assets.

virtual unsigned int	GetAssetsFrameNclones ()
	Optionally, a ChPhysicsItem can return multiple asset coordinate systems; this can be helpful if, for example, when a ChPhysicsItem contains 'clones' with the same assets (ex. More...

virtual bool	GetCollide () const
	Tell if the object is subject to collision. More...

virtual void	SyncCollisionModels ()
	If this physical item contains one or more collision models, synchronize their coordinates and bounding boxes to the state of the item.

virtual void	AddCollisionModelsToSystem ()
	If this physical item contains one or more collision models, add them to the system's collision engine.

virtual void	RemoveCollisionModelsFromSystem ()
	If this physical item contains one or more collision models, remove them from the system's collision engine.

virtual void	GetTotalAABB (ChVector<> &bbmin, ChVector<> &bbmax)
	Get the entire AABB axis-aligned bounding box of the object. More...

virtual void	GetCenter (ChVector<> &mcenter)
	Get a symbolic 'center' of the object. More...

virtual void	StreamINstate (ChStreamInBinary &mstream)
	Method to deserialize only the state (position, speed) Must be implemented by child classes.

virtual void	StreamOUTstate (ChStreamOutBinary &mstream)
	Method to serialize only the state (position, speed) Must be implemented by child classes.

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	SetNoSpeedNoAcceleration ()
	Set zero speed (and zero accelerations) in state, without changing the position. More...

virtual int	GetDOF_w ()
	Get the number of scalar coordinates of variables derivatives (usually = DOF, but might be different than DOF, ex. More...

virtual int	GetDOC ()
	Get the number of scalar constraints, if any, in this item.

virtual int	GetDOC_c ()
	Get the number of scalar constraints, if any, in this item (only bilateral constr.) Children classes might override this.

virtual int	GetDOC_d ()
	Get the number of scalar constraints, if any, in this item (only unilateral constr.) Children classes might override this.

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	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	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	InjectConstraints (ChSystemDescriptor &mdescriptor)
	Tell to a system descriptor that there are constraints of type ChConstraint in this object (for further passing it to a solver) Basically does nothing, but maybe that inherited classes may specialize this.

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	ConstraintsLoadJacobians ()
	Adds the current jacobians in 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
	Gets the numerical identifier of the object.

void	SetIdentifier (int id)
	Sets the numerical identifier of the object.

double	GetChTime () const
	Gets the simulation time of this object.

void	SetChTime (double m_time)
	Sets the simulation time of this object.

const char *	GetName () const
	Gets the name of the object as C Ascii null-terminated string -for reading only!

void	SetName (const char myname[])
	Sets the name of this object, as ascii string.

std::string	GetNameString () const
	Gets the name of the object as C Ascii null-terminated string.

void	SetNameString (const std::string &myname)
	Sets the name of this object, as std::string.

void	MFlagsSetAllOFF (int &mflag)

void	MFlagsSetAllON (int &mflag)

void	MFlagSetON (int &mflag, int mask)

void	MFlagSetOFF (int &mflag, int mask)

int	MFlagGet (int &mflag, int mask)

virtual std::string &	ArchiveContainerName ()

Friends
class	ChSystemParallel

Additional Inherited Members
Protected Attributes inherited from chrono::ChLink
ChBodyFrame *	Body1
	first connected body

ChBodyFrame *	Body2
	second connected body

ChVector	react_force
	store the xyz reactions, expressed in local coordinate system of link;

ChVector	react_torque
	store the 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::vector< std::shared_ptr< ChAsset > >	assets
	set of assets

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
	the time of simulation for the object

Member Function Documentation

◆ GetActuatorForce()

double chrono::ChLinkTSDA::GetActuatorForce ( ) const

inline

Get the constant acutation force.

Meaningful only if no force functor is provided.

◆ GetDampingCoefficient()

double chrono::ChLinkTSDA::GetDampingCoefficient ( ) const

inline

Get the value of the damping coefficient.

Meaningful only if no force functor is provided.

◆ GetSpringCoefficient()

double chrono::ChLinkTSDA::GetSpringCoefficient ( ) const

inline

Get the value of the spring coefficient.

Meaningful only if no force functor is provided.

◆ Initialize()

void chrono::ChLinkTSDA::Initialize	(	std::shared_ptr< ChBody >	body1,
		std::shared_ptr< ChBody >	body2,
		bool	pos_are_relative,
		ChVector<>	loc1,
		ChVector<>	loc2,
		bool	auto_rest_length = `true`,
		double	rest_length = `0`
	)

Initialize the spring, specifying the two bodies to be connected, the location of the two anchor points of each body (each expressed in body or absolute coordinates), and the imposed rest length of the spring.

Parameters

body1	first body to link
body2	second body to link
pos_are_relative	if true, point locations are relative to bodies
loc1	point on 1st body (rel. or abs., see flag above)
loc2	point on 2nd body (rel. or abs., see flag above)
auto_rest_length	if true, initializes the rest length as the distance between loc1 and loc2
rest_length	rest length (no need to define if auto_rest_length=true.)

◆ IsStiff()

void chrono::ChLinkTSDA::IsStiff ( bool val )

inline

Declare the forces generated by this spring as stiff (default: false).

If stiff, Jacobian information will be generated.

◆ SetActuatorForce()

void chrono::ChLinkTSDA::SetActuatorForce ( double f )

inline

Set constant actuation force (default: 0).

Used only if no force functor is provided.

◆ SetDampingCoefficient()

void chrono::ChLinkTSDA::SetDampingCoefficient ( double r )

inline

Set damping coefficient (default: 0).

Used only if no force functor is provided.

◆ SetRestLength()

void chrono::ChLinkTSDA::SetRestLength ( double len )

inline

Set spring rest (free) length.

Optionally, the free length can be calculated from the initial configuration (see Initialize).

◆ SetSpringCoefficient()

void chrono::ChLinkTSDA::SetSpringCoefficient ( double k )

inline

Set spring coefficient (default: 0).

Used only if no force functor is provided.

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

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

Description

Classes

Public Member Functions

Friends

Additional Inherited Members

Member Function Documentation

◆ GetActuatorForce()

◆ GetDampingCoefficient()

◆ GetSpringCoefficient()

◆ Initialize()

◆ IsStiff()

◆ SetActuatorForce()

◆ SetDampingCoefficient()

◆ SetRestLength()

◆ SetSpringCoefficient()